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ED 203 130 CE 029 243 AUTHOR Bynum, Michael H.: Taylor, Edward A. TITLE Machinery Repairman 3 6 2. Rate TrainingManual and Nonresident Career Course. Revised. INSTITUTION Naval Education and Training Command,Washington, D.C. REPORT NO NAVEDTRA-10530-E PUB DATE 81 NOTE 671p.: Photographs andsome diagrams will not reproduce well.

EDRS PRICE MF03/PC27 Plus Postage. DESCRIPTORS Behavioral Objectives; CorrespondenceStudy; *Equipment Maintenance: Rand ;Independent Study: Instructional Materials: LearningActivities: Machine Repairers: *Machine Tools;*Mechanics (Process): Military Training: Postsecondary Education: *Repair: Textbooks: *Tradeand Industrial Education IDENTIFIERS Navy ABSTRACT This Rate Training Manual (textbook)and Nonresident Career Course form a correspondence self-studypackage to teach the theoretical knowledge and mental skillsneeded by the Machinery Repairman Third Class and Second Class. The15 chapters in the textbook are (1)Scope of the Machinery Repairman Rating:(2) Toolrooms and Tools:(3) Layout and Benchwork: (4) Metals and Plastics:(51 Power and Machines:(6) Offhand Grinding of Tools:(7) and Attachments:(8) Basic Engine Operations:(9) Advanced Engine Lathe Operations: (10)Turret Lathes and Operations:(11) Machines and Milling Operations:(121 , Planers, and Engravers: (13)Precision Grinding Machines: (14 Metal Buildup:and (15) The (Shipboard) Repair Department and Repair Work. Appendixesinclude Tabular Tnformation of Benefit to Machinery Repairman(23 tables), Formulas. for Spur Gearing, Formulas for DiametralPitch System, and Glossary. The Nonresident Career Course follows theindex. It contains T1 assignments, which are organized into thefollowing format: textbook assignment and learning objectives withrelated sets of teaching items to be answered. (YLB)

*********************************************************************** Peproductions supplied by EDRSare the best that can be made from the original document. *********************************************************************** A A I I

8

'V U S DEPARTMENT OF HEALTH. EDUCATION &WELFARE NATIONAL INSTITUTE OP EDUCATION THIS DOCUMENT HAS SEEN REPRO- DUCED EXACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION ORIGIN. ATING IT POINTS OF VIEW OR OPINIONS et STATED 00 NOT NECESSARILY REPRE- SENT OFFICIAL NATIONAL INSTITUTE OF ti EDUCATION POSITION OR POLICY Although the words "he," "his," "him" appear in this manual for economy in communication, they are not intended to indicate gender nor to affront nor todisCriminateagainst anyone readingMachineryRepairman3 &2, NAVEDTRA 10530-E. MACHINERYREPAIRMAN 382

NAVEDTRA 10530-E

1981 Edition Prepared by MRCM Michael H. Bynumand MRC Edward A. Taylor PREFACE

This Rate Training Manual and Nonresident Career Course (RTM/NRCC) form a self-study package to teach the theoretical knowledgeand mental skills needed by the Machinery Repairman Third Class andMachinery Repairman Second Class. To most effectively train MachineryRepairmen, this package may be combined with on-the-job trainingto provide the necessary elements of practical experience and observation of techniques demonstrated by more senior Machinery Repairmen. Completion of the NRCC provides the usualway of satisfying the requirements for completing the RTM. The set of assignments in the NRCC includes learning objectives and supporting questions designedto help the student learn the materials in the RTM.

Revised 1981

Stock Ordering No. 0602.12-052.6510

Published by NAVAL EDUCATION AND TRAINING PROGRAM DEVELOPMENT CENTER

UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON, D.C. 1981

! THE UNITED STATES NAVY

GUARDIAN OF OUR COUNTRY The United States Navy is responsible for maintaining control of the sea and is a ready force on watch at home and overseas, capable of strong action to preserve the peace or of instant offensive action to win in war.

It is upon the maintenance of this control that our country's glorious future depends; the United States Navy exists to make it so.

WE SERVE WITH HONOR Tradition, valor, and victory are the Navy's heritage from the past. To these may be added dedication, discipline, and vigilance as the watchwords of the present and the future.

At home or on distant stations we serve with pride, confident in the respect of our country, our shipmates, and our families.

Our responsibilities sober us; our adversities strengthen us.

Service to God and Country is our special privilege. Weserve with honor.

THE FUTURE OF THE NAVY The Navy will always employ new weapons, new techniques, and greater power to protect and defend the United States on the sea, under the sea, and in the air.

Now and in the future, control of the sea gives the United States her greatest advantage for the maintenance of peace and for victory in war.

Mobility, surprise, dispersal, and offensive power are the keynotes of the new Navy. The roots of the Navy lie in a strong belief in the future, in continued dedication to our tasks, and in reflectionon our heritage from the past.

Never have our opportunities and our responsibilities been greater.

ii CONTENTS

CHAPTER Page

1. Scope of the Machinery Repairman Rating 1-1

2. Toolrooms and Tools 2-1

3. Layout and Benchwork 3-1

4. Metals and Plastics 4-1

5. Power Saws and Drilling Machines 5-1

6. Offhand Grinding of Tools 6-1

7. Lathes and Attachments 7-1

8. Basic Engine Lathe Operations 8-1

9. Advanced Engine Lathe Operations 9-1

10. Turret Lathes and Turret Lathe Operations 10-1

11. Milling Machines and Milling Operations 11-1

12. Shapers, Planers, and Engravers 12-1

13. Precision Grinding Machines 13-1

14. Metal Buildup 14-1

15. The Repair Department and Repair Work 15-1 APPENDIX I. Tabular Information of Benefit to Machinery Repairman (23 tables) Al-1

II. Formulas for Spur Gearing All -1

III. Formulas for Diametral Pitch System AIII-1

IV. Glossary AIV-1

INDEX I-1 Nonresident Career Course follows Index

iii "! I CREDITS

The illustrationsindicated below are included in this editionof Machinery Repairman 3 & 2, through thecourtesy of the designated companies, publishers, and associations. Permissionto use these illustrations is gratefully acknowledged. Permission toreproduce these illustrations and other materials in this publication should be obtainedfrom the source.

Source Figures

American Technical Society 5-30, 5-31

Armstrong-Blum Manufacturing 5-1, 5-2 Company

Armstrong Brothers Company 7-24

Brown & Sharpe Manufacturing 2-7, 2-11, 2-12, 2-14, 2-17, 2-20, Company 2-21, 2-23, 9-12, 11-5, 11-7, 11-8, 11-9, 11-10, 11-16, 11-17, 11-20, 13-27, 13-29

Bullard Co. 10-42, 10-43

Cincinnati-Bickfort Tool Company 5-25, 5-27

Cincinnati Milacron 11-1,11-2,11-4,11-11,11-12, 11-13, 11-15, 11-18, 11-19, 11-79, 11-82, 13-11, 13-15, 13-20, 13-21, 13-22, 13-23, 13-25, 13-27, 13-28

Cincinnati Company 12-1, 12-3

Clausing Corporation 11-3

Cleveland Twist Company 5-28, 5-37

DoAll Company 5-3, 5-5, 5-6, 5-7, 5-8, 5-9, 5-10, 5-11, 5-12, 5-13, 5-14, 5-15, 5-16, 5-17, 5-18, 5-19, 5-20, 5-21, 5-22, 5-23, 5-24, and table'4-1

iv Source Figures

Delta Manufacturing Company 5-26

Giddings & Lewis Co., 11-86 Division of Giddings & Lewis, Inc.

Groton Machine Company, Division of12-19, 12-20, 12-21, 12-22, 12-23, Kearney & Trecker Corporation 12-24, 12-25, 12-26, 12-27, 12-28, 12-29, 12-30, 12-31, 12-32

Grinding Wheel Institute 13-4

Herbert D. Hall Foundation 5-33, 12-2

Kearney & Trecker Corporation 11-10

Lucas Machine Division, The New 11-87, 11-88, 11-89, 11-90 Britian Machine Company

MacMillan Company* .4-2, 4-3

Monarch Machine Tool Company 7-1

Norton Company 13-13, 13-17, 13-18, 13-19

Precision Tool Co., Inc. 11-77

Reed-Prentice Corporation 7-3, 7-4

R.K. Le Blond I" iachine Tool Company7-41

Rockford Machine Tool Company 12-13

SIFCO Metachemical Ltd. 14-11, 14-12, 14-13, 14-14, 14-15, 14-16, 14-17,14-18, 14-19, and tables 14-1, 14-2, 14-3, 14-4, 14-5, 14-6,14-7,14-8,14-9,14-10, 14-11, 14-12

South Bend Lathe Works 5-32, 5-35, 7-2, 7-5, 7-9, 7-10, 7-11, 7-12, 7-13, 7-14, 7-15, 7-16, 7-17, 7-21, 7-27, 7-29, 7-32, 7-33, 7-34, 7-35, 7-36, 7-37, 7-38, 7-39, 7-40, 8-1, 8-4, 8-6, 8-9, 8-10, 8-11, 8-16, 8-18, 8-19, 8-20, 8-21, 8-22, 8-23, 8-24, 8-25, 8-26, 8-27, 8-28, 8-29, 9-2, 9-3, 9-4, 9-5, 9-6, 9-7, 9-8, 9-10, 9-11, 9-13, 9-19, 9-20, 9-21, 9-22, 9-23, 9-24, 9-25, 9-30

*From R. H. Drake: Aircraft Sheet MetalsCopyright 1947

u Source Figures

L.S. Starrett Company 2-4, 2-5, 2-10, 2-13

Warner & Swasey Co. 10-3, 10-4, 10-5, 10-6, 10-8, 10-9, 10-10, 10-11, 10-12, 10-13, 10-14, 10-15, 10-16, 10-17, 10-18, 10-19, 10-21, 10-24, 10-25, 10-26, 10-27, 10-30, 10-31, 10-34, 10-35, 10-36, 10-37, 10-38, 10-39, 10-40, 10-41

Wilson Mechanical Instrument 4-4, 4-5 Company

vi CHAPTER 1

SCOPE OF THE MACHINERYREPAIRMAN RATING

The official description of thescope of the your limiting factor and if you keep your eyes, Machinery Repairman rating is to "perform ears, and mind open, you will discover that there organizational and intermediate maintenanceon are many things going on around you that can assigned equipment and in support of other broaden your base of knowledge. You will finda ships, requiring the skillful use of lathes, milling certain pleasure and a source of pride in machines,boringmills,grinders,power developing new and more efficientways to do , drill presses, and other machine tools; something that has becOme so routine that portable m achinery;andhandtoolsand everyoneelse simply accepts the procedure measuring instruments found ina machine currently being used as the onlyone that will shop." That is a very general statement,not work. meant to define completely the types of skills and supporting knowledgethat an MR is TheskillacquiredbyaMachinery expected to have in the different paygrades. The Repairman in the Navy is easily translated into OccupationalStandardsforMachinery several skills found in the machine shops of Repairman contain the requirements whichare private industry. As a matter of fact,you would essential for all aspiring Machinery Repairmento be surprised at the depth and range' ofyour read and use as a guide in planningfor knowledge and skill compared toyour civilian advancement. counterpart when based on a somewhat equal length of experience. The trade in Tiejob of restoring machinery to good private industry tends to break up the -job working order, ranging asit does fro the descriptions into many different titles and skill fabrication of a simple pinor bushing tthe levels. The beginning skill level andone in which complete rebuilding of an intricategear sy tem, you will surely become qualified is "Machine. requires skill of the highest order at eachtask Tool Operator," a job often done by semiskilled level. Often, in the absence of dime'onal workers. The primary requirement of the jobis drawingsorotherdesigninformation,a to observe the operation, disengage the machine MachineryRepairmanmustdepend upon incaseof problems and possibly maintain ingenuityandknow-howtosuccessfully manual control over certain functions. Workers fabricate a rep. r part. who do these jobs usually have the abilityto operate a limited number of different types of One of the important productsyou will machines. Another job description found in realize from becoming a well trained and skilled privateindustryis"LayoutMan." The Machinery Repairman is versatility. Asyou gain requirement of this job is to layout work that is knowledge and skill in the operation of the tobemachinedbysomeoneelse.An many different types of machines found in Navy understanding of the operation and capabilities machine shops, you will realize thateven though of the different machines would be requiredas a particular machine is used mostly for certain well as the ability to read blueprints. Asyou types of jobs, it may be capable of accepting progress in your training in the Machinery many others. Your imagination will probably be rRepairman rating you will become proficient in MACHINERY REPAIRMAN 3 & 2

interpreting blueprints and planning thema- as a tender or repair ship. You will find that chining operations required. You will find that although a ship's workspace is relatively small laying out intricate parts is notso difficult with the will have more equipment this knowledge. A third job descriptionis than you might imagine. A lathe, drill press and "Set-up Man," a job which requires considerable grinder can almost be assured, but in manycases knowledge and skill, all within whatYou can a milling machine and a second lathe are also expect to gain as a Machinery Repairman. A available. A tender or repair ship is similar toa set-up man isresponsiblefor placing each factoryinthe types of equipment that are machine accessory and in theexact installed. You will find the capabilities of sucha position required to permit accurate production ship to be very extensive in all areas required to of work by a machine tool operator. An"All maintain the complex ships of today's Navy. A Around Machinist" in private industry isthe job Machinery Repairman is not destined to spend for which the average Machinery Repairman an entire career on sea duty. There are many would qualify as far as knowledge and skillis shoreestablishmentswhereyou maybe concerned. This person would be able to operate assigned.The Navyhasshore-basedrepair allmachines inthe shop and manufacture activities located at various places throughout partsfromblueprints.SomeMachinery the United States and overseas. Most of these Repairmen will advance their knowledgeand have wide-ranging capabilities for performing the skills throughout their Navy career to the point required maintenance. There are general billets that they could move intoa job as a "Tool and or assignments ashore that will not necessarily Maker" with little trouble. They also acquire be associated with the Machinery Repairman athorough knowledgeof engineering data rating, but which add to an individual's overall relative to design limitations, shop math and experience in other ways. . There are many other related fields where an experienced Machinery Repairman It would be difficult to attempt togo into could performinstrument maker, research and detail on the duties that you may perform at developmentmachinist,toolroomoperator, each of your assignments. You will find thaton quality assurance inspector, and ofcourse the small ships you may be the only Machinery supervisoryjobssuchas foremanor Repairman aboard. This requires that you be superintendent. self-motivating toward learning all you can to increase your ability as a Machinery Repairman The obvious key to holding downa pcsian and that you seek advice from sources offyour of higher skill, responsibility, andpc. *!if ship when you have an opportunity. You will be same both in the Navy and in Private . surprised at how good you really are whenyou You must work hard, take advantage- the makean honesteffortto do your best. skills and knowledge of those aroundyou, and Regardless of your assignment, you will havean take pride in what you do regardless ofhow opportunity to work with personnel from other unimportant it may seem to You. You havea 'ratings. This can be an experience in itself. There great opportunity ahead of you as a Machinery are many interesting skills to be found in the Repairman in the Navy; a chance to makeyour Navy. None of them are easy, but many will future more secure than it might have been. offer you some amount of knowledge that will increaseyoureffectivenessasa Machinery Repairman or a home do-it-your-selfer. TYPICAL ASSIGNMENTS AND DUTIES

As a Machinery Repairmanyou can be TRAINING assigned to a tour of duty aboard almostany type of surface ship, from a small fleet tug, Training is the method by which everyone which has a small 10- or 12-inch lathe,a drill becomes knowledgeable of and skilled inany press and a grinder, to a large aircraft carrier that activity, whether it's a job, a sport or something is almost as well equipped in the machine shop as routine as eating the proper foods. Training

1-2 Chapter 1SCOPE OF THE MACHINERYREPAIRMAN RATING

can take many forms and can be a conscientious Vou should consultwith your leading petty orunconscientiouseffortonyourpart. officer or career counselor to obtain the most However, you will make the mostprogress when current information regarding school availability you recognize the need to increase your level of and your eligibility to request attendance. knowledge, take the required action to obtain the training and fully apply allyour efforts and resources to realize the maximum benefit from the training. In the following paragraphs,we will RATE TRAINING MANUALS AND present a brief description of each of thetypes NONRESIDENT CAREER COURSES of training available toa Machinery Repairman. Keep in mind that the information listed peculiar to your rating and that the Navyhas Navy rate training manuals and nonresident many programs available which will allow you to careercoursesaredesignedasa self-study increase your general education. You can obtain method to provide instruction to personnel' ina information concerning theseprograms from .variety of subjects. You can chooseyour own your career counselor or education officer. pace in working the courses, And. you are allowed to refer to the book when tryingto FORMAL SCHOOLS decide on the best or correct answer. If youare to learn anything, you must work thecourse The Navy has available several schools which yourself and not take the answer fromsomeone, will provide an excellent backgroundin the else. Some rate training manuals and nonresident Machinery Repairman rating. Youmay have an careercoursesaremandatoryfor youto opportunity to attend one ormore of 'them complete to meet advancement requirements. during your career in the Navy. These courses are listedin the Manual For Advancement, BUPERINST 1430.16 (series) The fundamentals of machine shoppractice and in the current (revised annually) issue of the are taught in Machinery Repairman "A" school. BibliographyFor .AdvancementStudy, Classroom instructions provide the theory of NAVEDTRA 10052 (series), where they basic operating procedures, safety are precautions indicated by asterisks (*). Remember thatas and certain project procedures, while timespent youadvance youareresponsibleforthe in the ship provides a hands-onexperience, information in the rate training manualsfor the supervised by a trained and skilled instructor. paygrades below you, in addition to thecourses Some of the equipment thatyou can expect to work with in this for the next higher paygrade. Acourse offers an course are lathes, milling excellent opportunity to become familiar witha machines, drill presses, band saws, cutoffsaws, subject when you cannot be personally involved pedestal grinders and machines.The with the equipment. There are many small but length of the course and specific content may important points that will be covered in acourse vary from time to time to accommodate the that you otherwise may not learn. needs of the fleet. You will haveno difficulty at all in performing the work ina Navy machine shop if you apply yourself in MR "A" school. ON-THE-JOB TRAINING Advanced machine shop practice and the heat treatment of metals are taught in Navy schools also. These courses are usually attended On-the-job training is probably the most by personnel in their second and subsequent valuable of all the training methods available to enlistmentsat "C" school. Course content you. Thisiswhere you put the textbook generally covers the information and associated theories and general procedures into specific job equipment required for advancement to MR I practice in personal contact with the problem at and MRC, although the schools are not required hand. All those unfamiliar terms thatyou read to establish eligibility for advancement. about in a course now begin to fit intoa plan MACHINERY REPAIRMAN 3 & 2

that makes sensetoyou.The one very 3.ToolsandTheirUses,NAVPERS important thing for you to remember is that 10085 -B,providesspecificandpractical when you are unsure about something, ask information in the use of almost any handtool questions. An unusual job experience is of little you are likely to use. value to you if you have to wing your way through it tooth and nail, guessing at each new It is important that you keep abreast of step. The people that you work with and for nad required training manuals. To ensure that the to learn what they know by asking questlens, so most current manual is available, you should they won't think you anylesseffis or check Bibliography For Advancement Study, valuablewhenyouask.Therewill be NAVEDTRA 10052(series),andListof opportunities to tackle jobs which are difficult Training Manuals and Correspondence Courses, and seldom done, jobs which offer a great deal NAVEDTRA '10061(series).Both of these -of experience and knowledge. These are the jobs references are revised annually, so be sure you that you should be really aggressive in pursuing have the latest one. and eager to accept. Regardless of the profession or the employer, the person who gets ahead is Inaddition,therearethree sources of usually the one who is highly motivated toward technicalinformationthatareordinarily increasing personal capacity, thereby, becoming available on-board your ship: (1) NAVSHIPS' more valuable to his employer. The Navy is no Technical Manual, which contains the official different than any other employer in this sense. word on all shipboard machinery, (2) technical manuals provided by the manufacturers of machinery and equipment used by the Navy, and (3) machinist's handbooks. Most of these OTHER TRAINING. MANUALS books should be readily available. However, if they are not, your leading petty officer or division officer can request them through proper Some of the publications you will use are channels. subject to change or revision from time to timesome at regular intervals, others as the need arises. When using any publication that is SAFETY subject to change or revision, be sure that you havethelatestedition.When usingany publication that is kept current by means of As a Machinery Repairman, you will be change-s, be sure you have a copy in which all exposed to many different health and safety officialchanges have been made. Studying hazards every day. A great many of these are canceled or obsolete information will not help common to all personnel who work and live you to do your work or to advance; it is likely aboard a Navy ship or station, and some are to be a waste of time, and may even be seriously peculiar only to personnel who are involved with misleading. jobswithinmachineryspaces.Information concerning these can be found in both the The training manuals you must use in Fireman and the Basic Military Requirements conjunction withthisonetoattain your ratetraining manuals as well as instructions required professional qualifications are: prepared by your command. In this section we shall look at some of the more common safety hazards that you will find in a machine shop and 1.Mathematics, Vol1,NAVEDTRA some of the'precautions that you can take to 10069-D and Mathematics, Vol 2, NAVPERS prevent an injury to either yourself or someone 10071-B. These two volumes provide a review of else.You willfindthat safetyisstressed the mathematics you will nced in shop work. throughoutthismanualaswellasthe 2. BlueprintReadingandSketching, importance of an individual's responsibility to NAVEDTRA 10077-E, provides informationon not only be familiar with and observe all safe blueprint reading and layout work. workingstandardspersonally,butalsoto

1-4 Chapter1 SCOPE OF THE MACHINERY REPAIRMAN RATING encourage others to do so. Safety is a subject way to lift any heavy object is to get as close to where the "learn by doing" method does not the object as you can, spread your feet about a provide the greatest advantage. foot apart and squat down by bending your Your eyes are one of your most riceless knees. You should keep your back straight possessions. When you think about this fact and during the lift. When you grasp the object, lift try to imagine how you would get along without by using the muscles in your legs and hold the them,youwillagreethattheslight object close to your body. Walk slowly to your inconvenience caused by wearing safety glasses, destination and lower the part exactly as you goggles or a face shield is a small price to pay for lifted it. If you have to lift something higher eye protection. Safety glasses or goggles should than your waist, you should seek assistance. Of be worn any time you are around machinery in course, there is a limit to how much weight operation, includinghandiools,whether anyone can safely pick up and this should not be powered or nonpowered. Safety glasses that exceeded. have side guards are the most effective for 'keeping out small metal chips or particles from Good housekeeping practices may demand a grinding wheels. You should wear a face shield little more of your time than you are willing to and safety glasses at all times whenever you are give on some occasions, butthis is just as around any grinding operation. important to a safe shop as any other measure Another item or protection is safety-toe that you can take. Small chips made during a shoes. Granted, the additional weight of the operation can become very slippery steel reinforced toe does not make them the when allowed to collect on a steel deck. Long, most comfortable shoes that you can wear, but unbroken chips can trip or cut someone walking they do offer outstanding foot protection and past them. Lubricating oil that has seeped from they are much more comfortable than a cast. a machine or a cutting oil thrown out by the Look around your shop at the dents left in the machine can be an extreme hazard on a steel deck from objects being dropped. Do you think deck. All liquid spillage should be cleaned up your unprotected foot would fare any better? right away. If your job is causing a hazard to other personnel by throwing chips or coolant Some of the objects you will be handling in into a passageway, speak with your supervisor the shop will have sharp or ragged.edges on them about isolating the immediate area by stretching that can cut easily. You should remove as many tape across the area. Unused metal stock, small of these "burrs" as possible with a . In spite and large parts of equipment being worked on, of your filing efforts, heavy objects will still cut toolboxes and countless other objects should easily where there is a corner. A pair of leather not be left laying around the shop where traffic or heavy cotton work gloves will protect your can be expected to go or where a machine hands in these cases. You should NOT wear operator may have to be positioned. Most well gloves when operating machinery. The chances organized shops have a place for storing all of their being caught are too great. movable objects and this is the place for them. It Loose fitting clothing worn around moving will save you time when daily cleanup dr field machinery will test your strength if caught up in day comes along, and it may save a serious the rotating equipment. You would be amazed injury. at the strength a shirt has when being wound up on a machine. Rings, bracelets and other jewelry To protectyourself frominjurywhile can snag on projections of a rotating part and operating ship machinery, thereare several take a finger or other part of your body off things you can do. The first thing is to make before you know you have a problem. sure that you know how the machine operates, what each control lever does, the capability of How many times have you seen people themachine and especially where the stop bend over and pick up a heavy object by using button or clutch lever is in case an emergency their back? Chances are this same person will stopis required. All guards that cover gears, eventually injure himself or herself. The correct drive belts, pulleys or deflect chips should be in MACHINERY REPAIRMAN, 3 & 2

place at all times. Use the correct tool for the Notify the electric shop _when you feel job you are doing. This means more than usinga even a slight tingle while operating electrical scraper to remove instead of a 6-inch . equipment. Every machine or handtool hasa safe working limit that was determined by considering the Follow the safety precautions exactlyas stresses subjected to it under its intended use. prescribed by your maintenance requirement Excessive pressures could cause failure inuse cards when performing maintenance onyour with an injury following. equipment and be alert to other personnel who Whenever you are operating a machine, give have taken similar precautions. it your total concentration. Daydreaming should be saved until a more relaxed time. Ifyou must Always remember that electricitystrikes talk with someone, shut your machine off. without warning and, unfortunately, we cannot Electricalsafetyisnottheprivate always sit around and discuss 'what went wrong responsibility of the electricians. They can keep after an accident has happened. It is to your the equipment operating safelyif they are advantage to ask when you are notsure of notified when a problem exists. They cannot something. NEVER take unnecessary chances by make everyone observe safety precautions when hurrying or being inattentive. ALWAYS THINK working around electrically powered equipment. about what you are going to do beforeyou do This is a responsibility that each individual must it. accept and carry out. The electrical systems used on-board ships are not like those found in your home, so PURPOSES, BENEFITS, AND however efficient you may feelyou are as a LIMITATIONS OF THE handyman, do not attempt to makeany repairs PLANNED MAINTENANCE SYSTEM oradjustmentsonanyfaultyequipment on-board ship. Notify the electric shop and let The following material containsa brief the job be done by the trained electricians. discussiononthepurposes,benefits,and There are some basic safety precautions you limitations of the Planned Maintenance System. can observe while using electrical equipment: Use only authorized portable electric PURPOSES equipment which has been tested by the electric shop within the prescribed time period and is The Planned Maintenance System (PMS)was properly tagged to indicate such a test. established for several purposes:

Report all jury-rigged portable electrical 1.To reducecomplex maintenance to equipment to the electric shop. simplified procedures that are easily identified and managed at all levels. When a plastic cased or double-insulated 2. Tode finetheminimumplanned electrically powered tool is available,use it in maintenance required to schedule and control preference to an older metal cased tool. PMS performance. Ensure that all metal cased electrically 3. To describe the methods and tools to be powered tools have a three-conductor cable,a used. three-prong grounded plug and that theyare 4. Toprovideforthedetectionand plugged into the proper type receptacle. prevention of impending casuP lies. 5.To forecast and plan manpower and Wear rubber gloves when settingup and material requirements. using the metal cased tools or when working 6. To plan and schedule maintenance tasks. under particularly hazardous conditions and in 7. Toestimateandevaluatematerial environments such as wet decks. readiness.

1-6

1't U Chapter 1SCOPE OF THE MACHINERY REPAIRMAN RATING

8. To detect areas that require additional or information you need to perform the duties of improved personnel training and/or improved your rating. You should learn where to look for maintenance techniques or attention. accurate, authorh. ive, up-to-date information 9. To provide increased readiness of the on all subjects related to the naval requirements ship. for advancement and the occupational standards of your rating. BENEFITS

PMS is a tool of command. By using PMS, NAVSEA PUBLICATIONS the commanding officer can readily determine .whether his ship is being properly maintained. The publications issued by the Naval Sea `ft e liabilityisintensified.Preventive Systems Command are of particular importance maintenancereducestheneedformajor to engineering department personnel. Although corrective maintenance, increases economy, and you do not need to know everything in these saves the cost of repairs. publications, you should have a general idea of PMS assures better records, containing more where to find the information contained therein. datathat can beusefultothe shipboard maintenance manager. The flexibility of the Naval Ships' Technical Manual system allows for pmgramming of inevitable changesinemploymentschedules,thereby The Naval Ships' Technical Manual is the helping to better plan preventive maintenance. basic engineering doctrine publication of the Naval Sea Systems Command. The manual is Better leadership and management can be kept up-to-date by means of quarterly changes. realized by reducing frustrating breakdowns and As new chapters are issued they are being irregular hours of work. PMS offers a means of designated by a new chapter numbering system. improving morale and thus enhances the effec- tiveness of both enlisted personnel and officers. NAVSEA Deckplate LIMITATIONS OF PMS The NAVSEA Deckplateisa bimonthly The Planned Maintenance System is not technical periodical published by the Naval Sea self-starting; it will not automatically produce Systems Command for theinformation of good results. Considerable professional guid:nce personnel in the naval establishment on the isrequired.Continuousdirectionateach design,construction,conversion,operation, echelon oust be maintained, and one individual maintenance, and repair of naval vessels and must be assigned' both the authority and the theirequipment,andonothertechnical responsibilityateach level of the system's equipmentandonprogramsunderthe operation. cognizance of the command. This magazine is Training in the maintenance steps as well as particularlyusufulbecauseitpresents in the system will be necessary. No system is a informationthatsupplements andclarifies substitutefortheactualtechnicalability informationcontainedinthe Naval Ships' required of the officers and enlisted personnel Technical Manual.Itis also of considerable who direct and perform the upkeep of the interest because it presents information on new equipment. developmentsinnavalengineering.The NAVSEA Deckplatc was formerly known as the NAVSEA Journal. SOURCES OF INFORMATION MANUFACTURERS' TECHNICAL MANUALS One of the most useful things you can learn about a subject is how to find out more about it. Themanufacturers'technicalmanuals No single publication can give you allthe furnished with most machinery units and many 1.7

L 1 1 MACHINERY REPAIRMAN 3 & 2 items of equipment are valuable sources of S-group numbering system. The newer system, informationonconstruction,operation, used on all NAVSHIPS drawings since 1 January maintenance, and repair. The manufacturers' 1967, is a consolidated index numbering system. technical manuals that are furnished with most A cross-reference list of S -group numbers and shipboardengineering equipmentaregiven consolidated index numbers is given in Ship NAVSHIPS numbers. Work Breakdown Structure.

DRAWINGS ENGINEERING hANDBOOKS

SomeofyourworkasaMachinery For certain types of information, youmay Repairman re -jukes -n ability, to read and work need to consult various kinds of engineering frommechanicaldrawings.Youwillfind handbooksmechanical engineering handbooks, information on how to read and interpret marineengineeringhandbooks,piping drawings in Blueprint Pes,ling and Sketching, handbooks, machinery handbooks, and other NAVEDTRA 10077 (series). handbooks that providedetailed,specialized Inadditiontoknowing how toread technicaldata. Most engineering handbooks drawings,you must know how tolocate contain a great deal of technical information, applicable drawings. For somepurposes, the much of it arranged in charts or tables. To make drawingsincludedinthemanufacturers' the best use of engineering handbooks,use the technicalmanualsforthemachineryor table of contents and the index to locate the equipment may give you the informationyou information you need. need. In many cases, however, you will find it necessary to consult the on-board drawings. The on-boarddrawings,whicharesometimes ADDENDUM referred to as ship's plans or ship's blueprints, are listed in an index called the ship drawing In addition to a comprehensi' c index that is index.(SDI). printed in the back of this manui:i, you will find The SDI lists all working drawings that have the following: a NAVSHIPSdrawingnumber,all manufacturers'drawingsdesignatedas 1.Appendix I contains 23 tables, such as certificationdata sheets, equipment drawing decimal equivalents of fractions; division of the lists,and assembly drawings thatlistdetail circumference of a circle: formulasforlength, drawings. The on-board drawings are identified area, and volume; tapers, etc. You wili find this in the SDI by an asterisk(*). informationhelpfulinyour everyday shop work. Drawing are listed in numerical order in the 2.Appendix II is formulas for spur gearing. SDI. On-board drawings are filed accordingto 3.Appendix III shows the derivation of numerical sequence. There are two types of formulas for the diametral pitch system. numbering systems in use for drawings that have 4.Appendix IV isa glossary of terms NAVSHIPS numbers. The older system isan peculiar to the Machinery Repairman rating. CHAPTER 2

TOOLROOMS AND TOOLS

Your proficiency as a Machinery Repairman the space set aside for this purpose must be used is greatly influenced by your knowledge of tools as efficiently as possible. Since the number of and your skill in using them. The information toolsrequiredaboardshipisextensive, that you will need to become familiar with the toolrooms usuallytend to be overcrowded. correct use and care of the many powered and Certain peculiarities in shipboard toolrooms also nonpowered handtools, measuring instruments, require consideration. For example: The motion and gages is available from various sources to of the ship at sea requires that tools be made which you will have access. secureto prevent ,movement. The moisture Thisratetrainingmanualwillprovide content of the air requires-that the tools be information which applies to the tools and protected from corrosion. instruments usedprimarily by a Machinery Repairman.Additional information on tools Permanent bins, shelves, and drawers cannot that are commonly used by the many different easily be changed in the toolroom. However, naval ratings can be found in Tools and Their existing storage spaces can be reorganized by Uses, NAVPERS 10085-B. dividinglargerbins and relocating tools to provide better utilization of space.

TOOL ISSUE ROOM , , and other tools that do not have cutting edges may normally be stored One of your responsibilities as a Machinery in bins. They also may be segregated by size or Repairman is the operation of the tool crib or other designation. Tools with cutting edges tool issuing room. You shOuld ensure that the require More space to prevent damage to the necessarytoolsareavailableand ingood cutting .edges. Usually these tools are stored on condition andthatan adequate supply of shelves lined with , on pegboards, or on consumable items (oil, wiping rags, bolts, nuts, hangingracks.Pegboardsareespecially and screws) are available. adaptable for tools such as milling cutters. Some provision must be made to keep these tools from Operating and maintaining a toolroom is falling off the boards when the ship is rolling. simple if the correct procedures and methods are Storeprecisiontools(,dial used to set up a system. Some of the basic indicators and 'so forth) in felt-lined wooden considerations in operating a toolroom are (1) boxes in a cabinet to reduce the effects of the issue and custody of tools; (2) replacement vibration. This arrangement allows a quick daily of broken, worn, or lost tools; and (3) proper inventory. It also prevents the instruments from storage and maintenance of tools. being damaged by contact with other tools. Rotating bins can be used to store large supplies ORGANIZATION OF THE TOOLROOM of small parts, such as nuts and bolts. Rotating bins provide rapid selection from a wide range of Shipboard toolrooms are limited in size by sizes. Figures 2-1, 2-2, and 2-3 show some of the the design .characteristics of the ship. Therefore, common methods of tool storage.

2-1 MACHINERY REPAIRMAN 3 & 2

28.333.1 Figure 2 -1. Method of tool storage.

Frequently used tools should be locatednear locatingtools. theissuing door so Thesemarkingsshouldbe thattheyarereadily permanent; either stenciled with paintor on available. Seldom used tools shouldbe placed in stamped metal tags. out of the way areas such as on top of bins or in You will be responsible for the condition of spaces that cannot be used efficiently because of all the tools and equipment 1n the size and shape. Heavy tools should be placed toolroom. in You should inspect all tools aItheyare returned spaces or areas where a minimum of lifting is to determine if they need repairs required. Portable power tools should or adjustment. be stored Set aside a space for damaged toolsto prevent in racks. Provisions should be madefor electrical issueof thesetoolsuntilthey have bein extension cords and the cords of electricpower repaired. tools. You should wipe clean all returned toolsand give a light coat of oil to themetal surfaces. All storage areas such as bins, drawers,and Precision tools should be checked lockers should be clearly marked upon issue for ease in and return to determine if theyare accurate.

2-2 Chapter 2TOOLROOMS AND TOOLS

28.334 Figure 2-2.Method of tool storage.

28.335 Figure 2.3.Method of tool storage.

2-3 MACHINERY REPAIRMAN 3 & 2

Keep all spaces clean and free of dustto prevent whether you need to procuremore tools and foreign matter from getting into the working equipment for use. parts of tools. Plan to spend a portion of each day in Someselecteditems,calledcontrolled reconditioning damaged tools. This is important equipage,will require an increased level of in keeping the tools available for issue andwill management and control due to their highcost, prevent an accumulation of damaged tools. vulnerability to pilferage, or their importanceto the ship's mission. The number of tools and, CONTROL OF TOOLS instruments in this category under the controlof aMachineryRepairmanisgenerallysmall. You will issue and receive tools and maintain However, it is important thatyou be aware of control of custody of the tools. A method of controlled equipage items. Youcan get detailed identifying a borrower with the tool mustbe information about the designation of controlled established, and provisions must be madefor equipage from the supply department ofyour periodic inventory of available tools. activity. When these tools are received from the There are two common methods of tool supply department, your department headwill issue control: the tool check system andthe be required to sign a custody card, indicatinga mimeographed form or tool chit system. Some definite responsibility for managementof the toolrooms may use a combination of bothof item. The department head will then require these systems. For example: Tool checksmay be signed custody cards from personnel assignedto usedformachineshoppersonnel,and the division or shop where the item willbe mimeographed forms may be used for personnel stored and used. As a toolroom keeper,you may outside the shop. be responsible for controlling the issue ofthese tools and ensuring their good condition. If these Tool checks are either metal or plastic:disks special tools are lost or broken beyond repair, stampedwithnumbersthatidentifythe replacement cannot be made until the correct borrower. In this system the borrower presentsa survey procedures have been completed. Formal check for each tool, and the disk is placedoli a inventoriesoftheseitemsareconducted peg near the space from which the toolwas periodically as directed byyour division officer taken. The advantage of this system is thatvery or department head. little time is spent in completing theprocess. If the tools are loaned to all departmentsin As a toolroom keeper,you may have the ship, mimeographed forms generallyare additional duties as a supply representativefor used. The form has a space for listing thetools, your department or division. Informationon theborrower'sname,thedivisionor procurement of tools and supplies can be found department, and the date. This system hasthe inMilitary Requirements for PettyOfficer advantage of allowing anyone in the ship'screw 3 & 2,NAVEDTRA 10056-D. to borrow tools and of keeping the toolroom keeper informed as to who has the tools,and SAFETY IN THE TOOLROOM how long they have been out. AND THE SHOP You must know the location of toolsand The toolroom, because of its relatively small equipment out on loan, how long tools have size and the ,large quantity of different tools been out, and the amount of equipment and whicharestoredinit,can become very consumable supplies you haveon hand. To dangerous if all items are not kept stored in their know this, you will have to make periodic proper places. A ship at sea can be hazardous inventories. The inventory consists ofa count of especially in a crowded toolroom if the all tools, by types, in the toolroom and proper those precautions are not followed for securingall out on loan. In addition to control of custody, drawers,bins,pegboards, and other storage inventories will help you decide whethermore facilities. Fire hazards are sometimes overlooked strictcontrol of equipment is required and inthetoolroom. When you consider the

2-4

I) he I 14,, Chapter 2TOOLROOMS AND TOOLS flammable liquids and wiping rags stored or is no significant difference between gages and issued from the toolroom, there is a real danger measuring instruments. They are both used to present. compare the size or shape of an object against a scale or fixed dimension. However, there is a As a toolroom keeper, you will play a very distinction between measuring and gaging which important part in ensuring that your shipmates is easily explained by an example. Suppose that are workinginassafean environment as you are work in a lathe and want to possible.Severalof your jobsaredirectly know thediameter of the work. Take a connected to the good working order and safe , or perhaps an outside caliper, adjust use of tools in the shop. If you were to issue an itsopening to the exactdiameter of the improperly ground twist drill to someone who ,anddeterminethatdimension did not have the experience to recognize the numerically. On the other hand, if you want to defect, the chances of the person being injured turn a piece of work down to a certain size by thedrill"diggingin" or throwing the without frequently taking time to measure it, set workpiece out of the drill press would be very the caliper at a reading slightly greater than the real. A which has been sprung or worn final dimension desired; then, at intervals during oversize can become a real "knucklebuster" to turningoperations,gage,or"size,"the any unsuspecting user. An outside micrometer workpiece with the locked instrument. After the out of calibration can cause trouble if someone workpiece dimension has been reduced to the is trying to press fit two parts together using a dimension set on the instrument, you will, of hydraulic press. An electric-powered handtool course, need to measure the work while finishing that was properly inspected and tagged last week it to the exact dimension desired. but has had the plug crushed since then can kill the user. The list of potential disasters that you ADJUSTABLE GAGES asanindividualhavesomeinfluencein preventing is endless. The important thing to You can adjust adjustable gages by moving remember is that you as a toolroom keeper the scale or moving the gaging surface to the contribute more to the mission of the Navy than dimensions of the object being measured or first meets the eye. gaged. For example, on the dial indicator, you can adjust the face to align the indicating hand with the zero point on the dial. On verniers, SHOP MEASURING GAGES however, you would move the measuring surface to the dimensions of the object being measured. Practically all shop jobs require measuring or gaging. You will most likely measure or gage flat Dial Indicators orround,stock; the outside diameters of rods, shafts,orbolts;slots,grooves,and other Dialindicatorsareused'byMachinery openings; thread pitch and angle; spaces between Repairmen in setting up work in machines and surfaces; or angles and circles. incheckingthealignmentofmachinery. For some of these operations, you will have Proficiency in the use of the dial indicator will a choice of which instrument to use, but in require a lot of practice, and you should use the otherinstancesyouwillneedaspecific indicator as often as possible to aid you in doing Instrument. For example, when precision is not more accurate work. important, a simple rule or tape will be suitable, Dial indicator sets (fig.2-4) usually have but in other instances, when precision is of several components that permit a wide variation prime importance, you will need a micrometer of uses. The contactpointsallowuse on to obtain measurement of desired accuracy. different, types of surfaces, the universal sleeve permitsflexibility of setup, the and The term "gage," as used in this chapter, holding rods permit setting the indicator to the identifies any device which can be used to work, the hole attachment indicates variation or determine the size or shape of an object. There run out of inside surfaces of holes, and the tool

2-5 MACHINERY REPAIRMAN 3 & 2

INDICATORNDICATOR HOLDING NOD

CLAMP AND CLAMP HOLDING ROD

HOLE ATTACHMENT

--- UNIVIRSALSLEEVE

RASE HOLDING ROD

TOOL POST HOLDER CONTACT POINTS 28.2X Figure 2.4. Universal dial indicator.

post holder can be used in lathesetups. Figure 2-5 shows some practicalapplications of dial indicators. When youarepreparingto use a dial indicator,there are several things thatyou should check. Dial indicatorscome in different degrees of accuracy. Some willgive readings to one ten thousandths (0.0001) inch, while others will indicate to only fivethousandths (0.005) inch. Dial indicators also differ inthe total range or amount that they will indicate. Ifa dial indicator has a total ofone hundred thousandths (0.100) inch in graduationson its face and has a 28.3X Figure 2-5.Applications ofa dial indicator. total range of two hundred thousandths(0.200) inch, the needle will only maketwo revolutions FRAME before it begins to exceed its limit andjams up. The degree of accuracy andrange of a dial indicator is usually shown on its face. Before . you use a dial indicator, carefully depress the contact point and release it slowly;rotate the movable dial face so that the dial needleis on zero. Depress and release the contact point again MAIN SCALE and check to ensure that the dialpointer returns to zero; if it does not, have the dialindicator checked for accuracy. SLIDING JAW Vernier Caliper FIXED JAW

A vernier caliper (fig. 2-6)can be used to measure both inside and outside dimensions. 28.4B Figure 2.8.Vernier caliper.

2-6 ) Chapter 2 TOOLROOMS AND TOOLS

Position the appropriate sides of the jaws on the covered in Tools and Their Uses, NAVEDTRA surface to be measured and read the calipei from 10085-B. the side marked inside or outside as required. There is a difference in 'the zero marks on the Vernier Height Gage two sides that is equal to the thickness of the tips of the two jaws, so be sure to read the A vernier height gage (fig. 2-7) is used to lay correct side. Vernier are available in out work for machining operations or to check sizes ranging from 6 inches to 6 feet and are the dimensions on surfaces which have been graduated in increments of thousandths (0.001) machined. Attachments for the gage include the of an inch. The scales on vernier calipers made offset shown attached to the gage in by different manufacturers may vary slightly in figure 2-7. The offset scriber lets you measure length or number of divisions; however, they are fromthe withreadingstaken allread basically the same way.Siniplified directly from the scale without having to make instructions for interpreting the readings are any calculations. As you can see in figure 2-7, if

VERNIER WORK PIECE HEIGHT GAGE

28.41213DIX Figure W.Vernier height gags.

2-7 MACHINERY REPAIRMAN 3 &2 you were using a straight scriber, you would preset the gage. A dial boregage has two have to calculate the actual heightby taking into stationary spring-loaded points and account the distance between the surface an adjustable plate point to permit a variation inrange. These three and the zero mark.) Some models havea slot in pointsareevenly spaced to allow accurate the base for the scriber tomove down t,the centering of the tool in the bore. A fourth surface' and a scale that permits point, direct reading. the tip of the dial indicator, islocated between Another attachment is a rod that permitsdepth the two stationary points. By simply rocking readings. Small dial indicators that the connect to tool in the bore, youcan observe the amount of the scriber permit extremelyclose work in variation on thedial. Accuracy to one ten checking or laying out work. Avernier height thousandth (0.0001) ofan inch is possible with gage is read the same way as a vernier caliper. some models of the dial bore gage. Dial Vernier Caliper Internal Gage A dial vernier caliper looks muchlike a standard vernier caliper andis also graduated in one thousandths (0.001) of an inch. The main The internal groovegage is very useful for difference is that instead ofa double scale, as on measuring the depth of an 0-ringgroove or the vernier caliper, the dial vernierhas the inches other recesses inside a bore. Thistool lets you marked only along the main I.'," measure a deeper recess and one located farther of the caliper back in the bore than if andadialwithtwohands +o indicate you were to use an hundredths (0.100) and tho.15,..n.2, (0.001)of inside caliper. As with the dial boregage, this an inch. The range of the dial vernier caliper is tool must be set withgage blocks, a vernier usually 6 caliper, or an outside micrometer.The reading taken from the dial indicatoron the groove gage t)ial Bore Gage represents the difference between the desired recess or groove depth and the measured depth. Oneofthemostaccuratetoolsfor measuring a cylindrical boreor for checking a bore for out-of-roundnessor taper is the dial Universal Vernier Protractor bore gage. The dial boregage (rig, 2-8) does not give a direct measurement; itgives you the The universal vernier bevelprotractor (fig. amount of deviation froma preset size or the 2-9) is the toolyou will use to lay out or amount of deviation fromone part of the bore measure angles on work to very close tolerances. toanother. A masterringgage,outside The vernier scale on the tool permitsmeasuring micrometer, or vernier calipercan be used to an angle to within 1/12° (5 minutes) andcan be used completely through 360°.Interpreting the reading on the protractor issimilar to the method used on the vernier caliper. MEASURING PLUNGER

...--SPRING LOADED Universal Bevel SHOE The universal bevel (fig. 2-10),because of EXTENSION ROD the offset in the blade, isvery useful for bevel WITH gear work and for checking angles TYPE CONTACT on lathe POINTS which cannot be reachedwith an ordinary bevel. The universal bevelmust be set and checked withaprotractor, or another 28.338 suitable angle-measuring device,to obtain the Figure 2-8.Dial bore gage. desired angle.

2-8

U Chapter 2TOOLROOMS AND TOOLS

Gear Tooth Vernier

A gear tooth vernier (fig. 2-11) is used to measure the thickness of a gear tooth on the pitch circle and the distance from the top of the tooth to the pitch chord, at the same time. The vernier scale on this tool is read in the same way as other verniers, except that graduations on the main scale are 0.020 inch apart instead of 0.025 inch.

Cutter Clearance Gage

The cutter clearance gage (fig. 2-12) is one of the simplest to use, yet it is suitable for gaging clearance on all styles of plain milling cutters which have more than 8 teeth and a diameter range from 1/2 inch to 8 inches. To gage a tooth with this instrument, bring the surfaces of the "V" into contact with the cutter and lower the gage blade upon the tooth to be gaged. Rotate the cutter sufficiently to bring the tooth face into contact with the,gage blade: If

28.337 Figure 2-9.Universal vbrnier bevel protractor.

28.5X 28.4k Figure 2- 10. Universal bevel. Figure 2-11.Gear tooth vernier.

2-9

Ow 6 MACHINERY REPAIRMAN 3 & 2

the angle of clearance on the toothis correct, it will correspond with the angle of thegage blade. Cutter clearance gages that havean adjustable gage blade for checking clearance angles of 0°-30° on mostcommon cutter styles are also available.

Adjustable Parallel

The adjustable parallel in figure 2-13consists of two wedges connectedon their inclined surfaces by a sliding dovetail. Anadjustable parallel can be locked atany height between its maximum and minimum limits. Thisinstrument, 4 constructed to about thesame accuracy of dimensions as parallel blocks, isvery useful in levelingand positioning setups ina milling machineorinashapervise. An outside micrometer is usually used to set theadjustable parallel for height.

Surface Gage

28.7X A surface gage (fig. 2-14) is usefulin gaging Figure 2-12.Cutter clearance gage. or measuring operations. It is used primarilyin

14..""'""44...a. E "VW

. r

r

28.8X Figure 2-13.Adjustable parallel. Chapter 2TOOLROOMS AND TOOLS

28.9X Figure 2-14.Setting a dimension on a surface gage. layout and Alignment work. The surface gage is Graduated Gages commonly used witha scribertotransfer dimensions and layout lines. In some cases a dial Graduated gages are direct reading gages in indicator is used with the surface gage to check that they have scales inscribed on them enabling trueness or alignment. you to take a reading while using the gage. The gages in this group are rules, scales, thread gages, FIXED GAGES and feeler gages. Fixed gages cannot be adjusted. They can RULES.The steel rule with holder set (fig. generallybedividedintotwocategories, 2-15A) is convenient for measuring recesses. It graduated and nongraduated. The accuracy of has a long tubular handle with a split for your work, when using fixed gages, will depend holding the ruled blade. The chuck can, be on your ability to determine the difference adjusted by a knurled nut at the top of the between the work and the gage. For example, a holder, allowing the rule to be set at various skilledmachinistcantake'adimension angles. The set has rules ranging from 1/4 to 1 accurately to within 0.005 of an inch or less inch in length. when using a common rule. Practical experience The angle rule (fig.2-15B) is useful in in the use of these gages will increase your measuring small work mounted between centers ability to take accurate measurements. or.alathe.The longsideof therule

2-11 0j MACHINERY REPAIRMAN 3 & 2

111111- 88

1"

1111101111 32

TRW ORDINARY 82 0 RULE

"*--- SCRIBER

RULE WITH HOLDER CENTER LINE OF WORK

KEYSEAT CLAMPS

28.10 Figure 2-15.Special rules for shopuse.

(ungraduated) is placedeven with one shoulder not allow them to become battered,covered of the work. The graduatedangle side of the rule with rust, or otherwise damaged can then be positioned easily over the work. in such a way that the markings cannot be readeasily. Do not Another useful device is thekeyseat rule (fig. 2-15C). It has use them for scrapers, for once rules losetheir a and a 6-inch sharp edges andsquare corners their general machinist's-type rule arranged to forma right usefulness is decreased. anglesquare.Thisruleandstraightedge combination, when applied to thesurface of a SCALES. A scale is similar in cylindrical workpiece, makes appearance to an excellent guide a rule, since its surface is graduated intoregular for drawing or scribing layoutlines parallel to spaces. The graduations on a scale, however, the axis of the work. You willfind this device differ from those very convenient when making keyseat on a rule because they are layouts either larger or smaller thanthe measurements on shafts. indicated. For example, You must take a half-size scale is care of your rules if you graduated sothat 1 expect them to give accurate inch on thescaleis measurements. Do equivalent to an actual measurementof 2 inches;

2 12 Chapter 2TOOLROOMS AND TOOLS a 12-inch long scale of this type is equivalent to 24 inches. A scale, therefore, gives proportional measurementsinsteadoftheactual measurements obtained with a rule. Like rules, scales are made of wood, plastic, or metal, and , they generally range from 6 to 24 inches.

.. 4,10)14 I ACME THREAD TOOL GAGE.This gage (fig. 2-16) is used to both grind the tool used to 5.16.2X machine Acme threads and to set the tool up in Figure 2.17. Center gage. the lathe. The sides of the Acme thread have an included angle of 29° (14 1/2° to each side), and this is the angle made into the gage. The width notch and the point of the gage has an included of theflat on the point of the tool varies angle of 60°. The gage is used primarily to check according to the number of threads per inch. and to set the angle of the V-sharp and other The gage provides different slots for you to use 60° standard threading tools. The centergage is as a guide when grinding the tool. Setting the also used to check lathe centers. The edges are tool up in the lathe is simple. First, ensure that graduated into 1/4, 1/24, 1/32, and 1/64 inch the tool is centered to the work as far as height for ease in determining the pitch of threadson is concerned. Then, with the gage edge laid screws. parallel to the centerline of the work, adjust the side of your tool until it fits the angle on the gage very closely. FEELER GAGE.A feeler (thickness) gage, like the one shown in figure 2-18, is used to CENTER GAGE.The center gage(fig. determine distances between two closely mating 2-17) is used like the Acme thread gage. Each surfaces. This gage is made like a jackknife with blades of various thicknesses. When you use a combination of blades to get a desired, gage thickness,trytoplacethethinner blades between the heavier ones to protect the thinner blades and to prevent their kinking. Do not force blades into openings which are too small; the blades may bend and kink. A good way to

5.16.1X 4.19 Figure 2-16.Acme thread gager Figure 2-18.Feeler (thicknest) NIL

2-13 MACHINERY REPAIRMAN 3 & 2

get the "feel" of using a feelergage correctly is graduated. Tilzy are used primarily for checking to practice with the gage on openings of known surfaces for straightness; however, they dimensions. can also be used as guides for drawingor scribing straight lines. Two types of straightedgesare shown in RADIUS GAGE.The radiusgage (fig. 2-19) figure 2-20. Part A shows is often underrated a straightedge made of inits usefulness to the steel which is hardened on the edges toprevent machininst. Whenever possible, the designof wear; it is the one you will probably use most most parts includes a radius located at the often. The straightedge shown in Part Bhas a shoulder formed when a changeismade in the knife edge and is usedfor work requiring diameter. This gives the partan added margin of extreme accuracy. strength at that particular place. Whena shoulder is machined in a place wherea radius Always keep a straightedge in a box when it should have been, the possibility that thepart is not in use. Some straightedgesare marked will fail by bending or cracking is increased.The with two arrows, onenear each end, which blades of most radiusgages have both concave indicate balance points. Whena box is not (inside curve) and convex (outside curve)radii in provided, place resting pads on the common sizes. a flat surface in a storageareawherenodamagetothe straightedge will occur from other tools.Then, place the straightedge so that thetwo balance Nongraduated Gages points set on the resting pads.

Nongraduated gages are used primarilyas MACHINIST'S SQUARE.The most standards, or to determine theaccuracy of form common typeof machinist'ssquareisa or shape. hardened steel blade securely attachedto a beam. The steel blade in NOT graduated.(See .Straightedgeslook fig.2-21.) This instrument isvery useful in very much like rules, except that theyare not checking right angles and in settingup work on shapers, milling machines, and drillingmachines. The size of machinist'ssquares ranges from 1 1/2 to 36 inches in blade length.The same care should be taken in storage, and use ofas is taken with a micrometer.

SINE BAR.A (fig. 0 2-22) is a precision tool used to establish angleswhich required extremely closeaccuracy. When used in

28.338 28.11X Figure 2-19.Fillet or radius gages. Figure 2-20.Straightedges.

2-14

4.) a.1ti Chapter 2TOOLROOMS AND TOOLS

PARALLEL BLOCKS.Parallel blocks (fig. 2-23) are hardened, ground steel bars that are used in laying out work or setting up work for machining. The surfaces of the parallel block are all.eitherparallelorperpendicular,as appropriate, and can be used to position work in a variety of setups with accuracy. They generally come in matched pairs and standard fractional dimensions. Care should be used in storing and handling to prevent damage. If it becomes necessary to regrind the parallel blocks, be sure to change the size stamped on the ends of the blocks.

28.12X GAGE BLOCKS.Gage blocks are used as Figure 2-21.Machinist's square. master gages to set and check other gages and instruments. Their accuracy is from eight millionths(0.000008)of an inchto two conjunction withasurfaceplateand gage millionths (0.000002) of an inch, depending on blocks, angles are accurate to 1 minute (1/60°). the grade of the set. To visualize this minute The sine bar may be used to measure angleson amount, consider that the thickness of a human work and to lay out an angle on work to be hair divided 1,500 times equals 0.000002 inch. machined, or work may be mounted directly to This degree of accuracy applies to the thickness the sine bar for machining. The cylindrical rolls of the gage block, the parallelism of the sides, and the parallel bar, which make up the sine bar, and the flatness of the surfaces. To attain this are allprecisiongroundandaccurately accuracy, a fine grade of hardenable alloy steel is positioned to permit such close measurements. groTind and then lapped until the gage blocksare Any scratches, nicks, or other damage should be so smooth and flat that when they are "wrung" repaired before the sine bar is used, andcare or placed one atop the other in the proper must be exercised in using and storing the sine manner, you cannot separate them by pulling bar.Instructions on using the sine bar are straight out. A set of gage blocks has enough included in chapter 3. different size blocks so that youcan establish

28.339 28.13X Figure 2-22.Sine bars. Figure 2-23.Parallel blocks.

2-15 MACHINERY REPAIRMAN 3 & 2

any measurement within the accuracy andrange of the set. As you mightexpect, anything so accurate requires exceptionalcare to prevent damage and to ensure continuedaccuracy. A NO-GO dust-free temperature-controlled atmosphere is !MEMIlissm-4G° preferred. After use, wipe each block clean ofall A. PLAIN CYLINDRICAL PLUG GAGE marks and fingerprints and coat it witha thin layer of white petrolatum to preventrust. MICROMETER STANDARDS.Micrometer standards are either disk or tubular shapedgages that are used to check outsidemicrometers for GAGE LINE. accuracy. Standards are made in sizes so that any size micrometer can be checked. They B. TAPERPLUG GAGE should be used on a micrometeron a regular basis to ensure continuedaccuracy. Additional information for the use of the standardsare given later in this chapter.

RING AND PLUG GAGES.A ringgage C. PLAIN CYLINDRICAL RING GAGE (fig. 2-24) is a cylindrical-shaped diskthat has a precisely ground bore. Ringgages are used to check machined diameters by slidingthe gage over the surface. Straight, tapered, and threaded GAGE LINE diameters canbecheckedbyusingthe D. TAPER RING GAGE appropriate gage. The ring gage is also usedto set other measuring instruments to thebasic dimensionrequiredfortheir 28.340 operation. Figure 2-24.Ring gage and pluggage. Normally, ring gages are available witha "GO" and a "NOT GO" size thatrepresents the tolerance allowed for the particular size or job. using the wire method for measuringis covered in chapter 9. A plug gage (fig. 2-24) is used forthe same types of jobs as a ringgage except that it is a solidshaft-shapedbarthathas a precisely MICROMETERS ground diameter for checking insidediameters or bores. Micrometers are probably the most often used precisionmeasuring instruments ina THREAD MEASURING WIRES.Themost machine shop. There are accurate method of measuring the fit many different types, or pitch eachhavingbeendesignedtopermit diameter of threads, without goinginto the measurement of surfaces for various applications expensiveand sophisticatedopticaland and configurations of workpieces.The degree comparator equipment, .isthread measuring of accuracy obtainable froma micrometer also wires.Thesewires areaccuratelysized, varies, with the mostcommon graduations being depending on the number of threadsper inch, so from one thousandth (0.001) inchto one ten that when they are laidover the threads in a thousandths (0.0001) inch. Information position that allows on the an outside micrometer to correct procedure for interpreting the readingon measure the distance between them, the pitch micrometers can be found in Toolsand Their diameter of the threadscan be determined. Sets Uses,NAVEDTRA 10085-B. A brief are available that contain all the description more common of the more common typesof micrometers is sizes. Detailed informationon computing and provided in the following paragraphs. Chapter 2TOOLROOMS AND TOOLS

RATCHET STOP

OUTSIDE MICROMETER MICROMETER

0

DEPTH MICROMETER INSIDE MICROMETER AND EXTENSION RODS AND EXTENSION RODS

4.20.1B Figure 2-25.Common types of micrometers.

Outside Micrometer interchangeableextensionrodsthatare assembled to the micrometer head vary in size An outside micrometer (fig. 2-25 and 2-26) by 1inch. A small sleeve or bushing, which is often called a micrometer caliper, or mike, is 0.500 inch long, is used with these rods in most used to measure the thickness or the outside inside micrometer sets to provide the complete diameter of parts. They are available in sizes range of sizes. Using the inside micrometer is ranging from 1 inch to about 96 inches in steps slightly more difficult than using the outside of 1 inch. The larger sizes normallycome as a set with interchangeable which providea range of several inches. The anvils have an adjusting nut and a locking nut to permit setting the micrometer with a micrometer standard. Regardless of the degree of accuracy designed into the micrometer, the skill applied by each individual is the primary factor in determining accuracyandreliabilityinmeasurements. Training and practice will result in a proficiency in using this tool that will benefit you greatly.

Inside Micrometer A. Frame D. Sleeve B. E. Thimble C. F. Ratchet stop An insie° micrometer (fig. 2-25) is used to diameters or between parallel 4.20.1A are available in sizes ranging from Figure 2-26.Nomenclature of an outside micrometer ;..; to about 107 inches. The individual caliper.

2 -17 MACHINERY REPAIRMAN 3 & 2

micrometer, primarily because thereis more pitch diameters up to 2 inches. Each micrometer chance of your not getting thesame "feel" or has a given range of number of threadsper inch measurement each time you check thesame thatcan be measured correctly. Additional surface. information on using this micrometercan be found in chapter 9. The correct way to measurean inside dia- meter is to hold the micrometer in place with one hand as you "feel" for the maximum Miscellaneous Micrometers possible setting of the micrometer by rocking the extension rod from left to right and in and out of the hole. Adjust the micrometer toa The machine tool industry has beenvery slightly larger measurement after each series of responsive to the needs of the machinist by rocking movements until no rocking from leftto designingandmanufacturingmeasuring right is possible and a very slight drag is felton instrumentsforpracticallyevery imaginable the in and out rocking movement. Thereare no application. If you find thatyou are devising specific guidelines on the number of positions measuring techniques for a particularly odd within a hole that should be measured. Ifyou application with the resulting measurements are checking for taper, then you should take being of questionable value and thatyou do it measurements as far apart as possible within the on a routine basis, maybe a special micrometer hole. If you are checking for roundnessor will make your work easier andmore reliable. concentricity of a hole, then you should take Some of the special micrometers thatyou may severalmeasurementsatdifferentangular have a need for are described in later discussions. positions in the same area of the hole. Youmay takethereadingdirectlyfrom theinside BALL MICROMETER.Thistype micrometer head, or you may usean outside micrometer has a rounded anvil anda flat micrometer to measure the inside micrometer. spindle.It can be used to check the wall thickness of cylinders, sleeves, rings, andother Depth Micrometer parts that have a hole bored in a piece of material. The rounded anvil is placed inside the hole and the spindle is brought intocontact with A depth micrometer (fig. 2-25) is usedto the outside diameter. Ball attachments thatfit measure the depth of holes, slots, , over the anvil of regular outside micrometers are recesses, and the distance from a surface tosome also available. When using the attachments, recessed part. This type of micrometer is read you must compensate for the diameter of the ballas exactly opposite from the method usedto read you read the micrometer. an outside micrometer. The zerois located toward the closed end of the thimble.The BLADE MICROMETER.A blade measurement is read in reverse and increases in micrometer has an anvil and a spindle thatare amount (depth) as the thimble moves toward thin and flat. The spindle does notrotate. This the base of the instrument. The extension rods micrometer is especially useful in measuring the come either round or flat (blade-like) to permit depth of narrow grooves suchas an 0-ring seat measuring a narrow, deep recessor groove. on outside diameters.

Thread Micrometer GROOVE MICROMETERS.Agroove micrometer looks like an inside micrometer with two flat disks. The distance between the disks The thread micrometer (fig. 2-25) is usedto increases as you turn the micrometer. It isused measure the depth of threads that have an to measure the width ofgrooves or recesses on includedangleof60°. The measurement either the outside or the inside diameter.The obtained represents the pitch diameter ofthe width of an internal 0-ringgroove is an excellent thread. They are available in sizes thatmeasure example.

2-18 Chapter 2TOOLROOMS AND TOOLS

CARE AND MAINTENANCE OF GAGES to spring, forcing the measuring surfaces out of line. The propercareandmaintenanceof 4. When a micrometer is not in actualuse, precision instruments is very important toa place it where it is not likely to be dropped. conscientious Machinery Repairman. To help Dropping a micrometer can cause the frameto you maintain your instruments in the most spring; if dropped, the instrument should be accurate and reliable condition possible, the checkedforaccuracybeforeanyfurther Navy has established a calibrationprogram that readings are taken. provides calibration technicians, the required 5.Before a micrometerisreturned to standards and procedures, and a schedule of how stowage, back the spindle away from the anvil, often an instrument must be calibrated to be wipe all exterior surfaces witha clean, soft reliable. When an instrument is calibrated,a cloth, and coat the surfaces witha light oil. Do is affixed to the instrument showing the not reset the measuring surfaces to close contact date the n was done and the date the because the protecting film of oilin these next calibration is .Whenever possible, you surfaces will be squeezed out. should use the Navy ibration program to verify the accuracy of yo rnstruments. Some MAINTENANCE OF MICROMETERS.A repair jobs, due to their sensitive nature, demand micrometer caliper should be checked forzero the reliability provided by theprogram. Infor- setting (and adjusted when necessary)as a mation concerning the procedures that youcan matter of routine to ensure that reliable readings use in the shop to check the accuracy of an are being obtained. To do this, proceed as instrumentiscontained' inthe upcoming follows: paragraphs. 1.Wipe the measuring faces, makingsure Micrometers that they are perfectly clean, and then bring the spindle into contact with the anvil. Use thesame The micrometer is one of the most used, and moderate force that you ordinarilyuse when oftenone of the most abused,precision taking a measurement. The reading should be measuring instruments inthe shop. Careful zero; if it is not, the micrometer needs further observation of the do's and don'ts listed below checking. will enable you to takeproper care of the micrometer you use. 2.If the reading is more thanzero, examine the edges of the measuring faces for burrs. 1.Always stop the work before takinga Should burrs 1)6 present,remove them with a measurement. Do NOT measure moving parts smallslipof oilstone;clean the measuring because the micrometer may get caught in the surfaces again, and then recheck the micrometer rotating work and be severely damaged. for zero setting. 2. Always open a micrometer by holding 3.If the reading is lets thanzero, or if a the frame with one hand and turning the zero reading is not obtained after making the knurled sleeve with the other hand. Neveropen correction described above,you will need to a micrometer by twirling the frame, because adjust the spindle-thimble relation. The method such practice will put unnecessary strainon the for setting zero differs considerablybetween instrument and cause excessivewear of the makes of micrometers. Some makes havea threads. thimble cap which locks the thimbleto the spindle; some have a special rotatable sleeveon 3.Apply only moderateforcetothe the barrel that can be unlocked; andsome have knurled thimble when taking a measurement. an adjustable anvil. Always use the friction slip ratchet if there is 3ne on the instrument. Too' much pressureon Methods For Setting Zero.To adjust the knurled sleeve will not only result in the an THIMBLE -CAP TYPE, back the spindleaway naccurate reading, but may also cause the frame from the anvil, release the thimblecap with the

2-19 MACHINERY REPAIRMAN 3 & 2

small spanner wrench provided for thatpurpose, from time to time for unevenwear of measuring and bring the spindle into contact with the anvil. threads and for concave wear of the measuring Hold the spindle firmly with one hand and faces because these defects are not detectableby rotate the thimble to zero with the other; after zero-setting checks. The test for uneven internal zero relation has been established, rotate the wear can be made by measuring a flat-surfaced spindlecounterclockwisetoopenthe standard; the test for concavity of measuring micrometer, and then tighten the thimblecap. faces, by measuring a cylindrical disk-Shaped After tightening the cap, check thezero setting standard. again to be sure that the thimble-spindle relation was not disturbed while the cap was being The procedure for making these tests and tightened. correcting the defects whichare found is as follows: First, check the micrometer forzero Toadjustthe ROTATABLE SLEEVE setting and adjust TYPE, unlock the barrel sleeve with the asnecessary. Then take small measurements of severaldifferentsize gage spanner wrench provided for that purpose, bring blocks or other accurate standards. the spindle into contact with the anvil,and If the micrometer readings do not agree with thegage rotate the sleeve into alignment with thezero mark on the thimble. After alignment, back the dimensions, wear in the internal parts of the spindle away from the anvil, and retighten the micrometer is indicated, and the micrometer barrel sleeve locking nut. Recheck for must be adjusted. Adjustment is made with the zero thread wear compensating nut: located inside setting, to be sure that you did not disturb the the thimble assembly. After the thimble-sleeve relation while tightening the lock gage block test nut. has been completed, measure several cylindrical standardsofdifferentsizes.Discrepancies To set zero on the ADJUSTABLE ANVIL between micrometer readings and the marked TYPE, bring the thimble tozero reading, lock (actual) sizes of the standards indicatethat the the spindle if a spindle lock is provided, and measuring surfaces are concave. This condition loosen the anvil lock screw. After the lockscrew can be corrected by the measuring faces has been loosened, bring the anvil intocontact on a true flat surface. After lapping the faces of with the spindle, making sure that the thimbleis the micrometer, reset the instrument forzero still set on zero. Tighten the anvilsetscrew lock reading and measure the cylindrical standards nut slightly, unlock the spindle, and back the again. spindle away from the anvil; then lock the anvil setscrewfirmly. After locking the setscrew, Inside Micrometers.These instrumentscan check the micrometer forzero setting to make be checked for zero setting adjustedin about the sure that the anvil was not moved out of same way as a micrometer caliper; the main position while the setscrewwas being tightened. difference in the method of testing isthat an The zero check and methods of adjustment accurate micrometer caliperisrequired for of course apply directly to micrometersthat transferring readings to and from the standard will measure to zero; the PROCEDURE FOR when an inside micrometer is being checked. LARGER MICROMETERS is essentially the Micrometersofalltypesshouldbe same except that a standard must be place,' disassembledperiodicallyforcleaning between the anvil and the spindle in order and to get lubrication of internal parts. When this isdone, a zero measuring reference. For example,a each part should be cleaned in 2-inch micrometer is furnished with noncorrosive, a 1-inch solvent, completely dried, and then givena standard. To check for zero setting, place the lubricating coat of watchmaker's oilor a similar standard between the spindle and the anviland light oil. 'measure the standard. If zero is not indicated, the micrometer needs adjusting. Vernier Gages

Testing For And Correcting Errors By Use Vernier gages also require careful handling Of Standards.A micrometer must betested and proper maintenance if theyare to remain

2-20 Chapter TOOLROOMS AND TOOLS

accurate. The following instructions applyto by misuse and lack of proper maintenance. The vernier gages in general: following instructions apply to dials in general:

1.Always loosen the binding screws before 1.As previously mentioned, be sure that attempting to move sliding arms, the dial you have selected to use has therange capibility required. When a dial is extended 2. Never forceagageintoposition. beyond its design limit, some lever, smallgear or Forcing, besides c ...ming an inaccurate heading,is rack must give to the pressure. The dial will be likely to force the arms out of alignment. rendered useless if this happens. 2. Never leave a dial in contact withany 3. When taking a measurement,use only surface that is being subjected toa shock (such gentle pressure on the fine adjustmentscrew. as hammering a part when dialing it in) or an Heavy pressure will force the two scalesout of erratic and uncontrolled movement that could parallel. cause the dial to be overtraveled. 3.Protect the dial when it is not being 4.Prior to putting a vernier gageaway, used. Provide a storage area where the dial will wipe it clean and give it a light coating of oil. not receive accidental blows and where dust, oil, (Perspirationfromhandswillcausethe and chips will not convect it. instrument to corrode rapidly.) 4. When a dial becomes stickyor sluggish in operating, it may be either damagedor dirty. Dials You may find that the pointer is rubbingthe dial crystal or that it is bent and rubbing thedial face. A sluggish dial shouldnever be oiled. Oil Dial indicators and other instruments that will compound the problems. A suitablecleaning have a mechanically operated dialas part of solvent should be used toremove all dirt and their measurement featuresare easily damaged residue. CHAPTER 3

LAYOUT AND BENCHWORK

As an MR 3 or MR 2 you will repair or assist machinery. These blueprints are usually stowed in repairing a great many types of equipment in an indexed file in the logmom, dainage usedonships.Inadditiontomaking,/control office, technical library, of other central replacement parts, you will disassemble an` location, where they will be readily availah'e for assemble equipment, make layouts of parts to bye reference. machined, and do precision work in fit mating parts of equipment. This is _known The following paragraphs cover brieflysome benchwork and includes practically ?i1 a important points in connection with working work other than actual machining from sketches and blueprints. They do not contair definitions of all drafting terms,or This chapter contains infoation that ycu informationregardingthemechanicsof should know to enable you to effective blueprint reading, both of which are covered in repairs to equipment. A brief discus on detail in the Rate Training Manual, Blueprint blueprints and mechanical drawings is include. 4. Reading and Sketching, NAVPERS 10077-E. because in many repair jobs you must reV heavily on information acquired from these Of the many types of blueprints you willuse sources. Other sources on information that you aboard ship, the simplest is the PLAN VIEW. should study for details on specific equipment This blueprint shows the position, location, and includethe NA VSHIPS' Technical Manual, use of the various parts of the ship. You will use manufacturers' technical manuals and Rate plan views to fiyd your duty and battle stations, the sickbay, barber shop, and other parts of Training Manuals that have information related the ship. to the equipment on which you are working. In addition to plan views, you will find aboard ship other blueprintq called assembly prints, unit or subassembly prints, and detail MECHANICAL DRAWINGS prints. These prints show various kinds of AND BLUEPRINTS machinery and mechanical equipment. ASSEMBLY PRINTS show the various parts A mechanical drawing, made with special of the mechanism and how the partsfit instrumentsandtools,givesatrue together. Individual mechanisms, suchas motors representationofanobjectto be made, and pumps, will be shown on SUBASSEMBLY includingitsshape,size,description, PRINTS. These show location, shape, size, and specifications as to material to be used, and relationships of the parts of the subassembly method of manufacture. A blueprint isan exact unit. Assembly and subassbmbly printsare used Jcate of a mechanical drawing. Forference to learn operation and maintenance of machines purposes, every shipisfurnishe eprint and equipment. copies of all important mechani wings Machinery Repairmen are most interested in used inthe:construction of itshull and DETAIL PRINTS; thesewillgive you the

3-1 4 0 MACHINERY REPAIRMAN 3 & '2

information required to make a new part-They heat generated by the cutting operations. This is show size, shape, kind of material, and method especially importantin checking dimensions of finishing. You will find them indispensable in during finishing operationa, if work is being your work. machined to close tolerance.

WORKING FROM DRAWINGS COMMON BLUEPRINT SYMBOLS In learning to read machine drawings you Detailprintsusuallyshowonlythe must first become familiar with the .common individual part that you must produce. They terms,symbolsandconventions(general show two or more orthographic views of the practice)thatarenormallyused.The object,, and in special cases they may showan information in figures 3-2, 3-3, and 3-4 will isometric projection without dimension lines. provide the basic data that you will need to An isometric projection shows how the part will interpret blueprints. As you study each of the look, when made. various lines and symbols refer back to figure 3-1 to see how each is used in blueprints. Each drawing or blueprint has a number in the title box in the lower right-hand corner of Surface Texture the print. The title box also shows the part name, the scale used, the pattern number, the Control over the finished dimensions of a material required, the assembly or subassembly part is no longer the only factor you must print number to which the part belongs, and the consider when deciding how you will do a job. names or initials of the persons who drew, The degree of smoothness, or surface roughness, checked, anclalwroved the drawings. (See fig. has become very important in the, efficiency, and 3-1.) life of a machine part. A finishedsurface may appear to be Accurate and satisfactory fabrication of a perfectly flat; however, upon close examination part described on a drawing depends upon how with surface finish measuring instruments, the well the MR does the following: surface is found to be formed of irregular waves. On top of the waves are other smaller waves Correctly reads the drawing and closely which we shall refer to as peaks and valleys. observes all data thereon. These peaks and valleys are used to determine the surface roughness measurements of height Selects the correct material. and width. The larger waves are measured to give tree waviness height and widthmeasurements. Selects the correct tools and instruments Figure 3.5 illustrates the general location of the for laying out the job. various areas for surface finish measurements and the relation of the symbols to the surface Usesthebaselineorreferenceline characteristics. method bf locating the dimensional points Surface roughness is the measurement of the duringlayout,therebyavoiding cumulative finely spaced surface irregularities, the height, errors (described later in this chapter). width, direction, and shape of which establishes thepredominantsurfacepattern.These Strictlyobservestolerancesand irregularitiesarecaused by thecutting or glower as. abrading action of the machine tools that have been used to obtain the surface. One method of Accuratelygauges and measuresthe measuring the irregularities is by using special work throughout the fabricating process. measuring instruments equipped with a tracer arm. The tracer arm has either a diamond or a Givesdueconsideration,when sapphiredontactpoint witha 0.0005-inch .uuring, for expansion of the workpiece by radius. The tracer arm travels across the surface

3-2 NOTES: I. NILEJS OTHERWISE SPECIFIED: V ALL OVER BREAK SHARP EDGES .013A MAX INSIDE CORNERS .010R MAX FILLETS

2. PAINT AS INDICATED IN ACCORDANCE WITH MAYOR° OSTO 112, SYSTEM NO. 22

3. INTERPRET DIMENSIONS, SYMBOLS, ETC, IN ACCORDANCE WITH LISTED DOCUMENTS, ASFOLLOWS. .312 +:44: DIA S HOW DIMENSIONS AND TOLERANCES MIL- STO-S8 EQUALLY SPACED SCREW now cesstaroa wt.-STD-SA B .004 OIAI THREAD ONIENSIONS AND TOLERANCES MSS HANDBOOK H211 SURFACE ROUGHNESS SYMBOLS MIL-STD-10X ABBREVIATIONS MIL-STD-12S

1.730 DIA :gas

.426

1.000 1- .01:4 .12R

I GIS0

Yaw11.1841 I 111M1110111 Me w ol 1011.106111, MCI* I144111 I II nat. HINOKII / mu ffiliga-13ANF00-S-1133, F: NHL 'CATION ALT! SAE 1011 2

Nun M.Detail drawing of be UNE STANDARDS

NAME CONVENTION DESCRIPTION AND APPLICATION EXAMPLE .. HEAVY UNBROKEN LINES VISIBLE L INES USED TO INDICATE VISIBLE EDGES OF AN OBJECT 0

MEDIUM LINES WITH SHORT I I EVENLYSPACED DASHES HIDDEN LINES USED TO INDICATE CONCEAL ED EDGES Iu J

THIN LINES MADE UP OF LONG AND SHORT DASHES ALTERNATELY oirta SPACED AND CONSISTENT IN , NE 1 LENGTH __-* USED TO INDICATE SYMMETRY ABOUT AN AXIS AND LOCATION OF CENTERS

THIN L INES TERMINATED WITH ARROW HEADS AT EACH END DIMENSION LINES USED TO INDICATE DISTANCE MEASURED

THIN UNBROK EN L INES 14---- EXTENSION LINES USED TD INDICATE EXTENT OF DIMENSIONS

'4, XTO THD, THIN LINE TERMINATED WITH ARROW. HEAD DR DOT AT ONE END L FADER USED TD INDICATE A PART, DIMENSION OR OTHER REFERENCE

MEDIUM SERIES OF ONE LONG DASH AND TWO SHORT DASHES EVENLY SPACED . PH AN TOM ENDING WITH LONE DASH OR DATUM L INE USED TO INDICATE ALTERNATE POSITION I OF PARTS, REPEATED DETAIL OR TO INDICATE A DATUM

THIN SOL ID RUL ED L INES WITH I FREEHAND ZIGZAGS I BREAK 4.-"'"".1\/ (LONG) --'/Vit- URPODUITROEDRETD C;FEI.SIINZEEATOPE DDRABJEWCINTCAND REDUCE DETAIL r."

THICK SOL ID FREE HAND LINES BREAK ISIORTI USED TO INDICATE A SHORT BREAK

CUTTING DR VIEWING r1 THICKSOLIDL INES WITH ARROWHEAD PLANE TO INDICATE DIRECTICH IN WHICH SECTION OR PLANE IS VIEWED DR VIEWING TAKEN PLANE OPTIONAL /// I //// I //

CUTTING THICK SHORT DASHES PL ANE FOR ift,.. 0 COAPIL E X OR USED TO SNOW OFFSET WITH ARROW. /, OFFSET ow HEADS TO SHOW DIRECTION VIEWED //// VIEWS AP.)

Figure 3-2.Lin characteristics and conventions for MIL-STD drawings. 142.46

1 3-4 Chapter 3LAYOUT AND BFNCHWORK

e FLATNESS & STRAIGHTNESS

ANGULARITY .002 TM I J_ PERPENDICULARITY DATUM PARALLELISM II SYMBOL REFERENCE TOLERANCE REFERENCE (THIS FEATURE (TO DATUM (WITHIN.001 TO 0 CONCENTRICITY SHALL BE A) REGAROLESS OF DATUMSTVI PERPENDICULAR) FEATURE SIZE) TRUE POSITION

O ROUNDNESS

SYMMETF1 -L A.001 wag tumuli, mum. 8 C31 CONDITION

(RFS) REGARDLESS OF 0 FEATURE SIZE 86.8213 Figure 3-4.Feature control symbol incorporating datum CO3 DATUM IDENTIFYING SYMBOL reference.

65.82A Figure 3-3.Geometric characteristic sybmols.

ROUGHNESS HEIGHT TYPICAL FLAW (SCRATCH) 11111P-4/ i aWdrill011111/ 4- SURFACE ROUGHNESS WAVINESS LAY (DIRECTION OF WIDTH HEIGHT DOMINANT PATTERN) (INCHES) ROUGHNESS-WIDTH CUTOFF (INCHES) WAVINESS WIDTH (INCHES)

WAVINESS WAVINESS WIDTH (INCHES) HEIGHT (INCHES

ROUGHNESS ROUGHNESS-WIDTH CUTOFF HEIGHT RATING (INCHES)

63 LAY

.005 -q SURFACE ROUGHNESS WIDTH (INCHES)

128.43 Figure 3-5.Relatlon of symbols to surface characteristics.

3-5 , MACHINERY REPAIRMAN .3 & 2

and the contact point movesup and down the 002 002-i peaks and valleys. The movement of the contact pointis 63 amplifiedelectrically and recorded' 63 32 63 63 graphically on a graduated tape. From thistape the various measurementsare determined. A The basic roughness symbol is a check mark. This symbol is supplemented witha horizontal 75° extension line above it when requirements such as waviness height, waviness width, or contact 63 63 63 area must be specified in the symbol. A drawing _L 005 that shows only the basic symbol indicates that the surface finish requirements are detailed in the Notes block. The roughness height ratingis placed at the top of the short leg of the check 126.44 (part A, fig. 3-6). If onlyone number is shown Figure 3.6. Symbols used to indicate surfaceroughness, for roughnessheight,itisthe maximum waviness, and lay. permissible roughness height rating; iftwo are

LAY SYMBOL DESIGNATION EXAMPLE

LAY PARALLEL TO THE BOUNDARY LINE REPRESENT- ...... m ING THE SURFACE TO WHICH THE SYMBOL APPLIES. DIRECTION OF TOOL MARKS

LAY PERPENDICULAR THE BOUNDARY LINE REPRE- nnr1111111 DIRECTION SENT ING THEIC FATO TO WHICH THE SYMBOL 1"11111 OF TOOL APPLIES. MARKS

LAY ANGULAR IN BOTH DIRECTIONS TO BOUNDARY ;*X,44***". DIRECTION LINE REPRESENTING THE SURFACE TO WHICH SYMBOL '+,t4W444. OF TOOL APPLIES. x MARKS

1

LAY MULTIDIRECTIONAL h..1104 lit'qI, -,,. -.vo . )[11 6..%. 10. W..v.

LAY APPROXIMATELY CIRCULAR RELATIVE TO THE CENTER OF THE SURFACE TO WHICH THE SYMBOL APPLIES. Al LAY APPROXIMATELY RADIAL RELATIVE TO THE ACM, CENTER OF THE SURFACE TO WHICH THE SYMBOL it.NO,U44 APPLIES. 441...... 411 R PA'` Ile .446P.

128.45 Figure 3.7. Symbols Indicating the direction of lay.

3-6 ttA Chapter 3LAYOUT AND BENCHWORK shown, the top number is the maximum (part B, slightly above the point of the surface roughness fig. 3-6). A point to remember is that the smaller symbol as shown in part F of figure 3-6. (Figure the number in the roughness height rating, the 3-7 shows the six symbols that indicate the smoother the surface. direction of lay.) Waviness height values are shown directly The roughness width value is shown just to above the extension line at the top of the long the right and parallel to the lay symbol. The leg of the basic check (part C, fig. 3-6). Waviness roughness width cutoff is placed immediately width values are placed just to the right of the below the extension line and to the right of the waviness height values (part D, fig. 3-6). Where long leg of the basic check mark. These symbols minimum requirements for contact or bearing for roughness width are shown in parts G and H surfaces must be shown, the percentage is placed of figure 3-6. at the top of the long leg of the basic check In the past, an alpha-numeric symbol was :part E, fig.3-6). Any further surface finish used toindicate the degree of smoothness requirements that would have been shown in required on a part. This system was not very that location, such as waviness width or height, effective because no specific or measurable value will be shown in the Notes block of the drawing. was assigned to each classification of finish. A fine tool finish can mean different things to Lay is the direction of the predominant different people. Some of themore common airface pattern produced by the tool marks. The symbols that may be found on older blueprints rymbol indicating lay is placed to the right and are shown in table 3-1.

Table 3-1.Former Finish Designations

Preferred Symbols Meaning Alternate Symbols

F1 Rough Tool Finish V1 Fr. FIN. TF.

F2 , Fine Tool Finish V2 F. Fs. SF.

F3 Grind Finish V3 Fg. Gr.

F4 Polish V4 Bf. Buff

Fs Drill Vs Dr.

F6 Ream V6 Rm.

F7 File Finish V7 ff. Ff.

F8 Scrape Vs scr.

F9 Spot Face V9

Finish All F.A.O. f.a.o. Over

88.187

3-7 4 MACHINERY REPAIRMAN 3 & 2

Your shop may not have the delicate and strive for the greatest amount of accuracy. You expensive instruments usedto measure the can work many hours on a project and if it is irregularities of a surface although some of the not accurate, you will oftentimes have to start larger and more fully equipped repair facilities over. With this thought in mind, study carefully will have them. There are roughness comparison thefollowinginformationabout both the specimens available today that will serve all but English and the metric systems of measurement. the most critical applications. Thesecan be small plastic or metal samples, representing various English System roughness heights in several lay patterns. Figure 3-8 gives a sampling of some roughness height The inch is the basic (or smallest whole) unit values that can be obtained by the different of measurement in the English system. Parts of machine operations that you will encounter. Use the inch must be expressed as either common it as an estimating tool only, as it has thesame fractions or decimal fractions. Examplcis of shortcomings as the "F" values in table 3-1. common fractions are 1/2, 1/4, 1/8, 1/16, 1/32, and 1/64. Decimal fractions can be expressed UNITS OF MEASUREMENT witha numerator and denominator (1/10, 1/100, 1/1000, etc.), but in most machine shop Accuracy is the trademark of the Machinery work and on blueprints or drawings theyare Repairman, and it is to your advantage to always expressed in decimal form such as 0.1, 0.01, and

MACHINE ' ROUGHNESS HEIGHT (MICROINCHES) OPERATION 2000 1000 500 250 125 63 32 16 8 FLAME CUTTING

SAWING

PLANING

DRILLING MILLING

BROACH I. REAMING , TUFNING

ROLLEP JRNISHING ''r

HONING

POLISHING LAPPING

SAND CASTING

28.322 Figure 3-8.Roughness height values for machine operations.

3.8 4J Chapter 3LAYOUT AND BENCHWORK

0.001. Decimal fractionsare expressed in the example: 1.375 inches converted following manner: to centimeters is 1.375 inch X 2.540= 3.4925 cm. Further, 0.0008 inch converted to millimeters One-tenth inch is 0.0008 = 0.1 in. inch X 25.40 2: 0.0203mm. One-hundredth inch = 0.01 in. To convert from the metricsystem to the English system, One-thousandth inch divide the metric units of 0.001 in. measure by either 2.54 (for centimeters)or 25.4 (for millimeters). Asan example: 0.215 mm One ten-thousandth inch = 0.0001 in. converted to inches is 0.215mm + 25.4 = 0.0084 inch. You will occasionally need toconvert a common fraction to a decimal. This is easily .done by dividing the denominatorof the LIMITS OF ACCURACY fraction into the numerator. Asan example, the decimal equivalent of the fraction 1/16 inch is: You must work within the limitsof accuracy 1 ÷ 16 = 0.625 inch. Achart giving the decimal equivalents of the most specified on the drawing. A clearunderstanding common fractions is of TOLERANCE d ALLOWANCE will help shown in Appendix I. you to avoid m g small, but potentally dangerous errors. Metric System se terms may seem closely related but each ha very precise meaning and application. In following paragraphs we will The metric system is used bymany countries point out the m anings of these including the United States, and terms and the as a Machinery importanceo observingthedistinctions Repairman you should havean understanding of between them this system of measurement. Thebasic unit of linear measurement for the metricsystem is the Tolerance meter. In tht metric system themeter can be W,. g to the absolute or exact basic subdivide into the following parts: dimensio isimpractical and unnecessary in mostinances;therefore,thedesigner 10 decimeters (dm) calculates, or addition to the basic dimensions, an allowable variation. The amount of variation, 100 centimeters (cm) or limit of error permissible is indicatedon the or drawing as plus or minus (±) 1000 millimeters (mm) a given amount, such as ±0.005; ±1/64. The differencebetween theallowable minimum and the Therefore, 1 decimeter is 1/10 of allowance a meter, 1 maximum dimension is tolerance. Forexample, centimeter is 1/100 meter, and 1 millimeteris in figure 3-9: 1/1000 meter. The metric unit ofmeasurement most often used in the machinist trade isthe Basic dimension millimeter (mm). =4 Long limit = 4 1/64 If you understand the relationshipof the two systems, you can convert easilyfrom one Short limit = 3 63/64 system to the other. For example, 1meter is equal to 39.37 inches; 1 inch is equal to 2.54 Tolerance 1/32 centimeters (or 25.4 millimeters).To convert from the English system to the metric system, When tolerances are not actuallyspecified multiply the number of inchesby 2.54 (for on a drawing, fairly concrete assumptions centimeters) or 25.40 (for millimeters). can be As an made concerning theaccuracy expected, by

3.9 MACHINERY REPAIRMAN 3 & 2 .MIMIMINI=MM controlled so that the parts will have the proper allowance when assembled. For example, if a hole 0.250 inch in diameter with a tolerance of 0.005 inch (±0.0025) is prescribed for a job, and 4 ± a shaft to be fitted in the hole is to have a clearance allowance of 0.001 inch, the hole must firstbefinished within the limits and the 28.14 required size of the shaft determined exactly, Figure 3-9.Basic dimension and tolerance. before the shaft can be made. If the hole is finishedtotheupperlimitof thebasic dimension (0.2525 inch), the shaft would be using the following principles. For dimensions machined to 0.2515 inch or 0.001 inch smaller that end in a fraction of an inch, such as 1/8, than the hole. If the dimension of the shaft was 1/16,1/32,1/64,considertheexpected given with the same tolerance as the hole, there, accuracy to be to the nearest 1/64 inch. When would be no control over the allowance between the' dimension is given in decimal form, the the parts. As much as 0.005-inch allowance following applies: (either clearance or interference) could result.

If a dimension is given as 3.000 inches, the To providea method of retaining the accuracy expected is ±0.0005 inch; or if the requiredallowancewhilepermittingsome dimension is given as 3.00 inches, theaccuracy tolerance in the dimensions of the mating parts, expected is ±0.005 inch. The ±0.0005 is called, the tolerance is limited to one direction on each inshopterms,"plusorminusfive part. This single direction (unilateral) tolerance ten-thousandths of an inch." The ±0.005 is stems from the basic hole system. If a clearance called "plus or minus five thousandths ofan allowance is required between mating parts, the inch." hole may be larger but not smaller than the basic dimension; the part that fits into the opening Allowance may be smaller, but not larger than the basic dimension. Thus, shafts and other parts that fit Allowance is an intentional difference in into a mating opening have a minus tolerance dimensions of mating parts to provide the only, while the openings have a plus tolerance desiredfit.A CLEARANCE ALLOWANCE only. If an interference allowance between the permits, movement between mating parts when matingpartsisrequired,thesituationis assembled. For example, when a hole witha reversed; the opening can be smaller but not 0.250-inch diameter is fitted with a shaft that larger than thbasic dimension, while the shaft hasa0.245-inchdiameter,theclearance eau be larger. 'out not smaller than the basic allowance is 0.005 inch. An INTERFERENCE dimension. Tt refore you can expect tosee a ALLOWANCE is the opposite of a clearance tolerance such +.005, -0, or +0, -.005, but allowance. The difference in dimensions in this with the requi:ed value not necessarily .005. case provides a tight fit. Force is required when One way to gea better understanding of a assemblingpartsthathaveaninterference clearancecal° wanee.rnininterference allowance. If a shaft with a 0.251-inch diameter allowance, istg) note:, a rough sketch of the is fitted into the hole identified in the preceding piece and ace to the sketch where example, the difference between the dimensions they apply,. will give an interference allowance of 0.001 inch. As the shaft is larger than the hole, force is necessary to assemble the parts. LAW.'

What is the relationship between tolerance Laycutistheterm''.atdescribes the and allowance? In the manufacture of mating markIng surfaces tr provide an outline parts,thetolerance of each part must be for ;machining. A layout isItomparable to a

3 -10 1 Chapter 3LAYOUT AND BENCHWORK single view (end, top, or side) of a part which is Volume I, NAVPERS 10069-C; Mathematics, sketcheddirectlyontheworkpiece. Any Volume II, NAVPERS 10071-B; Tools and Their difficulty in making layouts depends on the Uses,NAVPERS10085-B,andBlueprint intricacies of the part to be laid out and the Reading and Sketching, NAVEDTRA 10077-E, number of operations require ake the part. for additional information. A flange layout, for examp,is relate imple as the entire layout can made on one surface MATERIALS AND EQUIPMENT of theblankflangeHowever, anintricate casting may require 1 yout lines on more than A scribed line on the surface of metal is one surface. This requires careful study and usually hard to see; therefore, a layout liquid is concentration to ensure that the layout will have usedtoprovideacontrasting background. the same relationships as those shown on the Commercially prepared layout dyes or inksare drawing (or sample) that you are using. available through the Navy supply system. Chalk When a part must be laid out on two or can be used, but it does not stick to a finished more surfaces, you may need to lay out one or surface as well as layout dye. The layout dyes, two surfaces and machine them to size before commonly used, color the metal surface witha using further layout lines. This prevents removal blue or copper tint. A line scribed on this of layout lints on one surface while youare colored surface reveals the color of he metal machining another. In other words, it would be through the background. useless to lay out the top surface of a part and The tools generally used for making layout machine off the layout lines while cutting the lines are the set, machinist's part to the layout lines of an end surface. square, surface gage, scribe, straightedge, rule, Through theprocess of computing and divider, and caliper. Tools and equipment used transferringdimensions,youwillbecome in setting up the part to be laid outare surface familiar with the relationship of the surfaces. plates, parallel blocks, angle plates, V-blocks, Understandingthisrelationshipwillbe of and sine bar. Surface plates have very accurately benefit in planning the sequence of machining scraped flat surfaces. They provide a mounting operations. table for the work to be laid out so that all lines in the layout can be made to one reference You should be able to hold the dimensions surface. Angle plates are used to mount the of a layout to within a tolerance of 1/64 inch. work at an angle to the surface plate. Angle Sometimes you must work to a tolerance of plates are commonly used when the lines in the even less than that. layout are at an angle to the reference surface. A layout of a partis made when the These plates may be fixed or adjustable; fixed directional movement or location of the part is angle plates are more accurate becauseone controlled by hand or aligned visually without surface is machined to a specific angle in relation the use of precision instruments (such as when tothebase.Adjustableangleplatesare work is done on or drill presses). In convenient to use because the angular mounting cuttingirregular shapes on sharers,planers, surfacecanbeadjustedtomeetthe lathes, or milling machines, layout lines are requirements of the job. V-blocks are used for made, and the tool or work is guided by hand. mounting round stock on the , surface plate. In making a part with hand cutting tools, layout Parallel blocks are placed under the work to is essential. locate the work at a convenient height. Mechanical drawing and layout are closely The sine bar is a precision tool used for related subjects; knowledge of one will help you determiningangleswhichrequireaccuracy to understand the other. A knowledge of general within 5 minutes of arc. The sine barmay be mathematics, trigonometry, and geometry, as used to check angles or establish angles for well as the selection and use of the required layout and inspection work. The sine bar must tools is necessary in doing jobs related to layout be used in conjunction with a surface plate and and mechanical drawing. Study Mathematics, gage blocks if accuracy is to be maintained. Use

3-11 MACHINERYREPAIR4k1-3---862_ of the sine bar willbe covered later in this chapter. point to the precedikgone can cause you to compound any error, thus\aninaccuratei layout. Toolmaker'sbuttons(figure3-10)are hardened and ground cylindrical pieces of steel, Making a layouton stock that one or used to locate the centers ofholes with extreme more machine finished surfaces usuall accuracy. You may use as r is easy. many buttons as Laying out a casting, however,presen 'ecial necessary on the same layout by spacingthem problems because the surfacesare too rou:and the proper distance fromeach other withgage not true enough to permit blocks. the use of squ s, surface plates, or othermounting methods*th Many other special tools,which may be any degree of accuracy. A castingusually m made by you, will be usefulin obtaining layouts be machined on all surfaces.Sufficient material that are accurate and easilydone. Transfer must be left outside thelayout line for truingup screws and punches for laying out froma sample the surface by machining.For example, a casting are two that you can useon many jobs and save might have only 1/8-inchmachining allowance time in doing the job. on each surface (or a total of 1 /4-inchoversize). It is obvious in thisexample that takingmore LAYOUT METHODS than 1/8 inch offany surface would mean the loss of the casting. Thelayout procedure is To ensure completeaccuracy when making especially important whenthere are, irregular layouts, establish a referencepoint or line on the surfaces or cored holes in thecasting. The layout lines work. This line, called thebaseline, is locatedso then must bewithinthe machining that you can use itas a base from which to allowance on all surfaces.Do NOT attempt to measure dimensions, angles, and linesof the make the layoutso that a maximum amount of layout. You canusea machined edge or material is removed fromone surface and a centerline as a reference line.Circular layouts, minimum amount fromanother surface. such as flanges,are usually laid out froma center point and a diameter line. Making Layout Lines You can hold inaccuracy in layouts toa Thefollowing minimum byusingthereference method informationappliesto because errors practically all layouts. Layoutlines are formed can be made only between the by using a reference reference line andone specific line or point. edge or point on the stock Making a layout by referencing or by using the surface plateas a base. Study each line or carefully the sectionon geometric construction as this will aid you in makinglayouts when a POINTS OF reference edge of thestock orasurface plate MEASUREMENTS mounting of the stockcannot be used.

BUTTON

WORK

28.323 Figure 3-10.Toolmaker's buttonsand their application. 28.16 Figure 3-11.Usinga scribe. 3.12 Chapter 3LAYOUT ANDBENCHWORK LINES SQUARE ORPRALLEL TO EDGES.When scribing layoulines on sheet metal, hold the scratch awl,or cribe, as shown in figure 3-11, leaning it towardthe direction in which it will be movedand laway from the straightedge. This will help scribea smooth line which will follow the edgeofe straightedge, template, or pattern at itspoin of contact with the surface of the metal. Tosquarealineonstockwitha combination square, placethe quaring headon the edge of the stock,as sho n in figure 3-12. Draw the line along eitheredge of the blade. The line will be square withthe egge of the stock against which the squaringhe ti is held; that is, the angle between the lineanthe edge will be 90°. To draw lines parallelto, an edge using a combination square, extende blade from the 28.17 squaring head the required Figure 3-13.Laying out parallellines with a combina- ance, such as the tion square. 2-inch setting shown in figu3-13. Secure the blade at this position.Scribea line parallel to the edge of the stock byhol g the scratch awl, or scribe, at the end of the maintains contact with the edgewhile the other lade as you move leg scribes the line. Holdthe caliper in such the square along the edge. lines so scribed, a with different blade settings way that the line will be scribedat the desired will be parallel to distance from the edge of thestock. the edge of the stock andpall el to each other. o scribe a line parallel to ANGULARLINES.To lay out an edge with a a 45° angle on stock, usinga combination hermaphroditecaliper, thecaliper,as shown in figure 3-14,so t at the curved leg

28.18 28.18 Figure 3-14.LayIng outa parallel line with a herma- Figure 3-12.Using the combinationsquare. phrodite caliper.

3-13 Tv MACHINERY REPAIRMAN 3 & 2

adjusting screw 4nd rotate the bladeso that the desired angle lines up with the index markon the body of the protractor head. The setting shown in figure 3-16 is 60°. Tighten thescrew to hold the setting. Hold the body of the protractor head in contact with a true edge of the work with the blade resting on the surface. Scribe thelines along the edge of the blade on the surface of the work. The angle set on the scale determines the angle laid out on the work. All lines drawn with the same setting; and from thesame true edge of the work, will be parallel lines. 28.19 Figure 115.Laying out a 46° angle. LAYING OUT CIRCLES AND IRREGULAR LINES.Circles or segments of circles are laid out froma center point. To square, place the squaring head on the edge of ensure accuracy, prick- the center joint to the stock, as shown in figure 3-15, and drawthe keep the point of the dividers from slipping°tit line along either edge of the blade. The line will of position. Use the center head and ruleas forin a 45° angle with the edge ofthe stock illustrated 'in figure 3-17; to locate the center of against which the squaring head is held. round stock. To find the center of square.and rectangular shapes, scribe straight lines from To draw angular lines with theprotractor oppositecornersoftheworkpiece.The head of a combinationsquare,loosen the intersection of the lines locates the center. To lay out a circle with a divider, take the setting of the desired radius from the rule,as shown in figure 3-18. Note that the 34noh setting is being taken AWAY from the endof the rule. This reduces the chance oferror as each point of the dividers can be seton a graduation. Place one leg of the divider at the center ofthe

28.20 29.21 Figure 3-16.Laying out angular lines. Figure 317.Locating the center of round stock.

3-14 Chapter 3LAYOUT AND BENCHWORK

proposed circle, lean the tool in the direction it will be rotated, and rotate it by rolling the knoried handle between your thumb and index finger. (A of fig. 3-19.)

When setting trammel points, shown in B tif figure 3-19, follow the same directionsas for a divider; you may need a steel tape to set the trammel points,

To lay out a circle with trammel points, hold one point at the centers lean the tool in the direction you plan to move the other point, and swing the arc, or circle, as shown in B of figure 3-19.

4.18 To transfer a distance measurement with Figure 3- 18. Sitting a divider to a dimension. trammel points, hold one point as you would for laying out a circle and swing a smallarc with the other point opened to the desired distance. Scribing an irregular line to a surface isa skill used in fitting a piece of stock,as shown in figure .3 -20, to a curved surface. In A of figure 3-20 you see the complete fit. In B of figure 3-20 the divider has scribed a line from left to right. When scribing horizontal lines, keep the legs of the diCrider plumb (one above the other).., When scribing vertical lines, keep the legs level. To scribe a line to an irregular surface, set the divider so that one leg will follow the irregular surface and the other leg will scribea line on the A material that is being fitted to theirregular surface. (See B of fig. 3-20.)

B A

28.22 21E23, Figure 3-19.Laying out circles. Figure 3-20.Laying out an irregular line froma surface.

3-15

b., MACHINERY REPAIRMAN 3 & 2

USING THE SURFACE PLATE.The clamping workpieces to the bar. Although surface plate is used with such tools the as , illustratedbars aretypical, thereis, a wide squares, V-blocks, surface gages, angle plates, varietyofspecializedshapes,widths,and and sine bar in making layout lines.Angle plates thicknesses. similar to the one shown in figure3-21 are used to mount work at an angle on the surface plate. The sine bar itself is veryeasy to set up and To set the angle of the angleplate, use a use. You do need to have a basic knowledge of protractor and rule of the combinationsquare set or use a vernier protractor. trigonometry to understand how it works.When a sine bar is set up, it always fcrmsa right triangle. A right triangle hasone 90° angle. The Part A of figure 3-22 showsa surface gage base of the triangle, formed by the sine \ -block combination used in bar, is laying out a piece the surface plate, as shown it figure3-23. The of ctockTo set a surface gage for height,first thetop of the surface plate and the om of the surface gage. Then place the squaring head of a combinationsquare, as shown in B of figure 3-22. Secure the scaleso that the end is in contact with the surfaceof the plate. Move the surface gage into position.

USING TEE SINE BAR.A sine baris a preciselymachinedtoolsteelbar usedin conjunction with two steel cylinders. In the type shown in figure 3-23, the cylindersestablish a precise distance of either 5 inchesor 10 inches from the center of one to the centerof the other, depending upon the model used.The bar itself has accurately machined parallelsides, and the of the two cylindersare parallel to the adjacentsidesof thebarwithina close tolerance. Equally close tolerancescontrol the cylinder roundness and freedom fromtaper. The slots or holes in the barare for convenience in

28.24 28.25 Figure 3-21.. Figure 3-22.Setting and usinga surface gage.

3-16 Chapter 3LAYOUT AND BENCHWORK

SINE BAR HYPOTENUSE (HYPOTENUSE) GAGE BLOCKS SIDE OPPOSITE (SIDE OPPOSITE)

SIDE ADJACENT A

SURFACE PLATE (SIDE ADJACENT)

Figure 123.Setup of the sin? bar. side opposite is made up of thegage blocks that Regular inspection of the sine bar will locate raise one, end of the sine bar. The hypotenuseis such defects before theyare able to affect the always formed by the sine bar,as shown in accuracy. When sine bars are stored for extended figure 3-23. The height of thegage block setting periods,allbare metal surfaces should be may be 'found in two ways. The first method is cleaned and then covered with a light film of oil. to multiply the sine of the angle needed bythe Placing a cover over the sine bar will further length of the sine bar. The sine of theangle may preventaccidentaldamageanddiscourage be found in any table of natural trigonometric corrosion. functions. For example, ifyou had to set a 10-inch sine bar to checka 30°5' angle on a GEOMETRIC CONSTRUCTION OF part, you would first go toa table of natural LAYOUT LINES.Sometimesyou will need to trigonometric functions and find the sineof scribe a layout that cannot be made 30°5'.Then using multiplyby10inches: conventional layout methods. For example,you .50126 X 10 = 5.0126, which would bethe cannot readily make straight and angular layout height of the gage blocks. The secondmethod is lines on sheet metal with irregular edges by using to use a table of sine bar constants. These tables a combination square give the height setting for set; neither can you any given angle (to the mount sheet metal on angle plates ina manner nearest minute) a 5-inch sine bar. Tables are that permits scribing angular lines. Geometric not normally available for 10-inch bars because construction is the answer to this problem. it is just as easy to use the sine of the angleand move the decimal point one place to the right. Use a divider to lay outa perpendicular FROM a point TO a line,as shown in figure Although sine bars have the appearance of 3-24. Lightly prick-punch point C, thenswing being rugged, they should receive thesame care any arc from C which will intersect the line AB, as gage blocks. Because of the nature of theiruse and prick-punch intersections D and Eas in the in conjunction with other toolsor parts that are figure. With D and E as centers, scribe heavy, two arcs theyaresubjecttoroughusage. which intersect at a point suchas F. Place a Scratches, nicks, and burrs should be removedor straightedge on points C and F. The line drawn repaired. They should be kept clean from along this straightedge from point Cto line AB dirt, sweat, and other corrosiveagents. will be perpendicular (90°) to line AB.

3-17 MACHINERY REPAIRMAN 3 & 2

C I j E F

A

28.27 Figure 326.Layout of a parallel line. >eF

28.26 Angle ABC (fig. 3-27) is given. With B Figure 124.Layout of a perpendicularfrom a point to as a a line. center, draw an arc cutting the sides of the angle at D and E. With D and Eas centers, and with a radius greater than half of arc DE, drawarcs intersecting at F. A line drawn from B through Ude a divider to lay out a perpendicular point F bisects the angle ABC. FROM a point ON a line,as shown in figure 3-25. Lightly prick-punch the point identifiedin Laying Out Valve Flange Bolt Holes the figure as C on line AB. Then set thedivider to any distance to scribe arcs which intersect AB Before describing the procedure for making at D and E with C as the center. Punch C and E valve flange layouts, we need to clarify the lightly. With D and E usedas centers and with terminology used in the description. Figure 3-28 the setting of the divider increased somewhat, shows a valve flange with the bolt holes marked scribe arcs which cross at points suchas F and on the bolt circle. The straight-linedistance G. The line drawn through F and Gwill pass between the centers of two adjacent holes is through point C and be perpendicular to line called the PITCH CHORD. The bolt holecircle AB. itself is called the PITCH CIRCLE. The vertical To lay out parallel lines witha divider, set lineacrossthe face of theflangeisthe the divider to the selected dimension.Then VERTICAL BISECTOR, and the horizontal line referringtofigure 3-26,from any points acrossthefaceoftheflangeisthe (prick-punched) such as C and Don line AB, HORIZONTAL BISECTOR. swing arcs EF and GH. Then drawline IJ The bolt holes center on the pitch circle and tangent to these two arcs and it will be parallel are equidistant; the pitch chord betweenany to line AB and at the selected distance fromit. Bisecting anangleisanother geometric construction with which you should be familiar.

0

A C 'E B I F

11.216 Figure 325.Layout of a perpendicular from a point on 11.219 a line. Figure 3-27.Bisecting an angle.

3-18

O Chapter 3LAYOUT AND BENCHWORK

should fit snugly and be flush with the faceof the flange.

2.Apply layout dye to the flange faces,or, if dye is not available, rub chalkon the flange faces to facilitate the drawing of lines which will be clearly visible.

VERTICAL PITCH CIRCLE BISECTOR 3.Locate the center of each flange witha PITCH CHORD surface gage, or with a center head and rule combination, if the flange diameter is relatively small. (See part A fig. 3-22 and fig. 3-17.) After you have the exact center point located on each flange,markthecenterwithasharp HORIZONTAL prick-punch. BISECTOR UGLY FITTING WOOD PLUG 4.Scribe the pitch or bolt circle, usinga pair of dividers. Check tosee that the pitch circle and the outside edge of the flangeare concentric. 28.28 Figure 3-28.Flange layout terminology. 5. Draw the vertical bisector\This linemust pass through the center point of the flange and it must be visually located directly in linewith two adjacent holes is exactly the saneas the the axis of the valve stem. (See fig. 3-28.) pitch chord between any other two adjacent holes. Note that the two top holes and thetwo 6. Draw the horizontal bisector. This line bottom holes straddle the vertical bisector; the must also pass through the center point ofthe vertical bisector cuts the pitch chord for each flange and must be laid out at right angles to the pair exactly in half. This is the standard method vertical bisector. (See fig. 3-28 and fig. 3-25.) of placing the holes fora 6-hole flange. In the 4-, 8-, or 12-hole flange, the bolt holes straddle Up to this point, the layout is thesame for both the vertical and horizontal bisectors. This all flanges regardless of the number ofholes. system of hole placement permits a valve to be Beyond this point, however, the layoutdiffers installed in a true verticalor horizontal position, with the number of holes. The layoutfor a provided, of course, that the pipe flange holes 6-hole flange is the simplest one and will be are also in standard location on the pitch circle. described first. Before proceeding with a valve flange layoutjob, find out definitely, whether the holesare to be SIX-HOLE FLANGE.Setyour dividers placed in standard position. Ifyou are working exactly to the dimension of the pitch circle on a "per sample" job, follow the layout of the radius. Place one leg of the dividers sample. on the point where the horizontal bisector,crosses the pitch circle on the right-hand side of the flange, Assumingthat point youhavebeengiven (1) in part A of figure 3-29, and drawa small arc information relative to the size and number of across the pitch circle at points (2) and (6). holes and the radius of the pitch circle, the Next, place one leg of the dividersat the procedure for setting up the layout for straight intersection of the pitch circle and horizontal globe or gate valves is as follows: bisector on the left-hand side of the flangepoint (4), and draw a small are;across the pitch circle 1. Fit a fine grain wood plug into the line at points (3) and (5). These points, ( 1to 6), opening in each flange. (See fig. 3-28.) The plug are the centers for the holes. Check the accuracy

3,19 MACHINERY REPAIRMAN 3 & 2

"WITNESS MARKS"

28.29 Figure 3-29.Development of a 6-hole flange.

of the pitch chords. To do this, leavethe lines cross the pitch circle, (1), (2), (3),and (4), dividers set exactly as you had them set for are the centers for the holes. To check the drawing the arcs. Starting from the located layout for accuracy, set your divider for the center of any hole, step around the circle with pitch between any two adjacent holes andstep the dividers. Each pitch chord must be equalto around the pitch circle. If the holesare not the setting of the dividers; if it is not,you have evenly spaced, find yourerror and correct it. an error in hole mark placement that must be Whenthelayoutiscorrect,followthe corrected before you center punch the marks for center-punching and witness-marking procedure the holes. After youare sure the layout is described for the 6-hole flange layout. accurate, center punch the hole marks and draw acircleof appropriate sizearound each EIGHT -HOLE FL ANGE. Figure 3 -31 center-punched mark and prick-punch "witness sho wnsthedevelopmentofan8 -hole. marks" around the circumferenceas shown in placement. The procedure is as follows: First, part B of figure 3-29. These witness marks will locate point E by the same methodas described be cut exactly in half by the drill to verifya for locating point (1) in the 4-hole layout. correctly located hole. Then divide arc AE in half by thesame method. The midpoint of arc AE is the location for thecenter FOUR-HOLE FLANGE.Figure 3-30 shows of hole (1). (See part A of fig. 3-31.) the development for a 4-hole flange layout. Next, set Set your dividers for distance A (1), and drawan arc, your dividers for slightly more than half the across the pitch circle line from A at point (8); distanceof arc AB, and thenscribean from B at points (2) and (3); from Cat (4) and intersecting arc across the pitch circle line from (5); and from D at (6) and (7). (See part B of points A, B, C, and D, as shown inpart A of fig. 3-31.) Now setyour calipers for distance AE figure 3-30. Next, drawa short radial line and gage the pitch chord foraccuracy. Then through the point of intersection of each pair of finish the layout as described inthe preceding arcs as shown in part B. The points where these paragraphs.

3-20 Chapter 3LAYOUT ANDBENCHWORK

28.30 Figure 3-30.Four-hole flangedevelopment.

MATHEMATICAL DETERMINATION OF The constants for specified numbersof holes are PITCH CHORD LENGTH.In additionto the given in table 3-2. geometricsolutions givenin the preceding Here is an example of theuse of the table. paragraphs, the spacing of valve flangebolt hole centers -Suppose a flange is to have 9 boltholes laid out canbedeterminedbysimple on a pitch circle with a diameter of 10 inches. multiplication, provided a constant valuefor the From the table, select the desired number of bolt holes is constant for a 9-hole known. The flange.Thepitchdiameter(10inches) diameter of the pitch circlemultiplied by the multiplied by the appropriate constant equals the length of the pitch constant (.342) chord. equals the length of the pitchchord (3.420

28.31 Figure 3-31.Eight-hole flange development.

3-21 MACHINERY REPAIRMAN 3 & 2

Table 3-2.Constants for Locating Centers of Flange many possible sources for this information. Job Bolt Holes orders generally give brief descriptions of the equipmentandtherequiredrepair. Manufacturers' technical manuals and blueprints No. bolt holes Constant givedetailedinformationonoperational characteristics and physical descriptions of the equipment. Operators can provide information 3 0.866 4 .7071 on specific techniques of operation and may 5 .5879 furnish clues as to why the equipment failed. 6 .5 The leading petty officer ofyour shop can 7 .4338 providevaluableinformationonrepair 8 .3827 techniques, and he will help you interpret the 9 .342 information. Use these sources of information to 10 .309 become familiar with the equipment before 11 .2817 attempting the actual repair work. Ifyou are 12 .2588 thoroughly acquainted with the equipment,you 13 .2394 will not have to rely on trial and error methods 14 .2225 15 whicharetime consuming and sometimes .2079 questionable in effectiveness. 16 .195 17 .184 There are specific techniques thatcan be 18 .1736 used in assembly and disassembly of equipment 19 .1645 which will improve the effectiveness of 20 .1564 a repair job. You should note such thingsas fastening devices, fits between mating parts, and theuses ofgasketsandpackingwhenrepairing 28.294 equipment. Noting the positions of parts in relation to mating parts or the unitas a whole is inches). Set a pair of dividers to measure 3.420 extremely helpful in ensuring that the partsare inches, from point to point, and step off around it rrect locations and positions when the unit the circumference of the pitch circle to locate is Awassembled. the centers of the flange bolt holes. Note, Inspecting the equipment before and during however, that the actual placement of the holes the repair procedure is necessary to determine inrelationtotheverticaland horizontal causes of defects or damage. The renewal or bisectors is determined separately. (This is ofno replacement of a broken or worn part ofa unit concern if the layout is for an unattached pipe may give the equipment an operational status. flange rather than for a valve flange.) Eliminatingthecauseof damage prevents recurrence. BENCHWORK Repairs are made by replacement ofparts, by machining the parts to new dimensions,or by In this chapter, we will consider benchwork using handtools to overhaul and reconditionthe as related to repair work, other than machining, equipment. Handtools are used in the repair in restoring equipment to an operational status. procedure in jobs such as filing and scrapingto In repairing equipment, benchworkprogresses in true surfaces and to remove burrs, nicks, and several distinct steps:obtaining information, sharp edges. disassembly of the equipment, inspection far It is often said that a repair job is incomplete defects,repair of defects,reassembly, and until the repaired equipment has been tested for testing. satisfactory operation. How equipment is tested Obtaining information about equipment is depends on the characteristics of the equipment. an essential step in making repairs. There are In some cases testing facilitiesare available in

3-22 Chapte13LAYOUTAND BENCHWORK

the shop. When these facilitiesare not available, the unit may be placed back inoperation and tested by normal use. PUNCH JOINTS MARKS ASSEMBLY AND DISASSEMBLY

You may not be completelyfamiliar with much of the equipment thatyou are required to disassemble, repair, and reassemble.You must, therefore, use techniques that will lid PUNCH you in MARKS remembering the position and locationof parts inrelativelyintricate mechanisms. The fol- lowinginformationappliesingeneralto assembly and disassembly of 28.32 any equipment. Figura 3-32.Mating parts location marks. Equipment should be disassembledin a clean, well-lighted work area. With plenty of. cause extensive damage if pressure is appliedto light, small partsare less likely to be misplaced theparts.If or lost, and small but important details hammersarerequiredto are more disassemble parts, use a malletor with a easily noted. Cleanliness of thework area as well soft face (lead, plastic, as the proper cleaning of the parts or rawhide) to prevent as they are distortion of surfaces. If boltsor nuts or other removed, decreases the possibilityof damage due to parts are stuck together due to corrosion,use foreign matter when theparts are penetrating oil to free the parts. reassembled.

Before starting any disassemblyjob, select PRECISION WORK the tools andparts you think you will need and take themtbthe work area. This procedurewill permit you to concentrateon the work without The ,majority of repair work thatyou unnecessaryinterruptionsduringthe perform will involve some amount ofprecision disassembly and reassemblyprocesses. hand work of parts. Broadly defined,precision hand work to the MachineryRepairman can Have a container at hand for holdingsmall range from using a file to removea or parts to prevent loss. Use tagsor other methods rough, sharp edge ona hatch dog to reaming a Df marking to identify theparts with the unit hole for accurately locatingvery close fitting from which theyare taken. Doing this prevents parts. To accomplish these jobs,you must be mixing parts of one piece ofequipment with proficient in the use of files,scrapers, precision partsbelongingtoanothersimilarunit, portable grinders, thread cutting tools,, 'specially if several pieces ofequipment are broaches, presses and oxyacetylene torches ming repaired in thesame area. Use a scribe or nick-punch to mark the relativepositions of nating parts thatare required to mate in a Scraping xrtain position. (See fig. 3-32.) Youmust pay ;lose attention to details of the equipment you Scraping produces a surface that ismore ire taking apart to fix in your mind how the accurate in fit and smoother in finish thana >arts fit together. When overhaulingequipment, surface obtained in a machinery operation.It is use no more force than necessary to disassemble a skill that requires a great deal of practice nd reassemble theparts. Doublecheck for before you become proficientat it. Patience, overlooked fastening devices if heavypressure is sharp tools and a light "feel"are required to squired to separate parts. Anoverlooked pin, scrape a surface that is smooth and uniform in :ey, or setscrew that locks parts in placecan fit.

3-23 ij ,Al.:PA I .1c. 2

Some of the tools you will use forscriipiag non .tying prussian blue. Turning the bearing on will be similar to files without the serrated the shaft (or the in the bearing) justa edges. They are available either straightor with short distance will lea ,4.1thin deposits of the various radii or curves for scraping an internal bluing on the high spots in the bearing babbitt. surface at selected points. Other scraper tools Then lightly scrape the high spots with a scraper may look like a paint scraper, pcissibly with a shaped to permit selective scraping of the high carbide tipattached. You may find that a spots without dragging along the other areas. Be scraper made by you from material in your shop very careful when doing this to prevent tapering will best suit the requirements of the jobat the bearing excessively in either the longitudinal hand. or radial direction. When all the high spots have been worked out, smooth out (or replace if A surface plate and nondrying prussian blue necessary) the bluing on the shaft or mandrel are required for scraping a flat surface. Lightly and repeat theprocess until an acceptable coat the surface plate with blue andmove the seating pattern is achieved. This job cannot be workpiece over this surface. The blue will stick rushed and done properly at thesame time. A to the high spots on the workpiece, revealing the poor seating pattern on a bearing could lead to areas to be scraped. (See fig. 3-33.) Scrape the an early failure when it is placed in service. areas of the workpiece surface that are blue and check again. Continue this process unit) the blue coloring shows on the entire surface of the Removal of Burrs and Sharp Edges workpiece. To reduce frictional "drag" between mating finished scraped surfaces, rotate the solid One of the most common injuries that surfaces so that each series of scraper cuts is occurs in machine shops is a cut or scratch made at an angle of 90° to the preceding series. caused by a sharp edge on a part. Whena pump This action gives the finished scraped surfacea or other machinery that has been overhauled, crosshatched or basket weave appearance. The binds or wipes with little or no operating time, crosshatched method also enablesyou to more an investigation will often reveal a sharp edge easily see where you have scraped the part. that has peeled or broken off and jammed into an area that has very little clearance. In spite of A shell-type, babbitt-lined, split bearingor a thisandother instancesthatcauseeither bushing often requires hand scraping toensure a discomfort or additional work, the removal of proper fit to the surface that it support3 or runs burrs and sharp edges is often overlooked by the on. To do this, very lightly coat the shaft (or a machinist. Close examination of the old partor mandrel the samesizeastheshaft)wi the blueprint will sometimes indicate thata machined radius is required. Regardless of the design or use of a part, a few seconds in removing these sharp edges witha file is time well spent.

Hand Reaming

When you need a round hole that is accurate in size and smooth infinish, reaming is the process that you would probably select. There are two types of reaming processesmachine reaming and hand reaming. Machine reaming requires a drill press, lathe, milling machineor other to hold and drive either the 28.33 or the part. Machine reaming will be- Figure 3-33.Checking a surface. covered in chapter 8. Hand reaming ismore

3-24 ./A Chapter 3LAYOUT AND BENCHWORK

accurate and the method you will probablyuse 0.006 inch larger for a 1/4-inch reamer to about most in precision benchwork. 0.012 inch larger for a 11/2-inch reamer. The A hand reamer has a straight shank anda adjustment is made by turning thescrew on the square machined on the end. It is driven by hand cutting end of the reamer. with a placedon the square end. Several different types of handreamers are The expansion reamer in C of figure 3-34has available, as shown in figure 3-34. Each ofthe a much greater range for varying size. Each different types has an application forwhich it is reamer is adjustable to provide an overlap of the best suited and a limitingrange or capability. smallest -darneter of the next largerreamer. The The solid hand reamer in part A of figure cutting blades are the insert type andCan be 3-34 is removed and replaced when they become used for general purpose reamingoperations dull. where a standard orcommon fractional size is Adjustment is made by loosening andtightening required. It is made with straight,helical, or the two nuts on each side of the blades. spiral fl,ttes. A helical flutedreamer is used The taper pin reamer in D of figure 3-34has when an interrupted cut, suchas a part with a a taper of 1/4 inch per foot and is used toream keyway through it, must be made. Thehelical a hole to accept a standard size taper pin. This flutes ensure a greater contactarea of the reamer is used most often when two parts cutting edges than the straight flutedreamer, requirea definite alignment position. When preventing the reamer from hangingup on the drilling the hole for thisreamer, it is often keyway and causing chatter, oversizing andpoor necessary to step drill through the part with finishes. several of different sizes to help reducethe cutting pressure put on thereamer. Charts which The expansion reamer in B of figure 3-34is give the recommended drill sizesare available in available as either straightor helical fluted. several machinist reference tpoks In any case, These reamers are used whena reamed hole the smallest drill used cannot belarger than the slightly larger than the standard sizeis required. small diameter of the taper pin. Expansion reamers can be adjustedfrom about The taper pipe reamer in E of figure3-34 has a taper of 3/4 inch per foot and is used to prepare a hole that is to be threaded witha A tapered pipe thread..

SOLID HAND REAMER The size of the rough drilledor bored hole to be hand reamed should be between 0.002 B t inch and about 0.015 inch (1/64)smaller than 0 the reamer size. A smoother andmore accurate EXPANSION REAMER SOLID reamed hole can be produced by keepingto a minimum the amount of material thata reamer is to remove. You must be carefulto keep the roughholefrombeingoversizedof EXPANSION REAMER INSERTED TOOTH out-of-round. This is a verycommon problem in drilling holes, and youcan prevent it only by t.-- using a correctly sharpened drill under themost TAPER PIN REAMER closelycontrolledconditionspossible. Information .on drilling can be found inchapter e4 S E Alignment of the reamer to the roughhole is TAPER PIPE REAMER acriticalfactorinpreventingoversized, out-of-round or bell-mouthed holes. Ifpossible, perform the reaming operation whilethe part is 28.324 still set up for the drilling.orboring operation. Figure 3-34.Hand reamers. Then insert a center in the spindleof the

3-25

; 4.7" L. MACHINERY REPAIRMAN 3 & 2

machine and place it in the center hole in the the broach to adjust the depth of the keyway shank of the reamer to guide it. cut. Another method of alignment is to fabricate broach is a relatively expensive cutting a with guide bushings made from bronze tool and r easily rendered useless if not used or a hardened steel to keep the reamer straight. and handfed properly. Like all other cutting When a rough casting or a part that has the tools, it should be stored so that no cutting edge reamed hole at an angle to its surface must be is in ccntact with any object that could chipor reamed, it is best to spot face or machine the dull it. Prep: ration of the part to be broachedis area nexttotheholesothattheyare as impo. tant as the operation itself. perpendicular. This will preventan uneven start The size of the hole should be such that the and possibly reamer breakage. In most reaming beginning pilot section enters freely but does operations, you will find that theuse of a not allow the broach to freely fall past the first lubricant will give a better reamed hole. The cutting edge or tooth. If the hole to be broached lubricant or helps to reduce heat has flat sides opposite each other, you need only and friction and washes away the chips that to measure across them and allow forsome error build up on the reamer. Soluble oil will normally from drilling. The broach will sometimes have serve very well; however, in some cases, a lard or the drill size printed on it. Besure the area sulfurized cutting oil may be required. When the around the hole to be broached is perpendicular reaming operationiscomplete, remove the on both the entry and exit sides. reamer from the part by continuing to turn the reamer in the same direction (Clockwise) and MostNavymachineshopapplications putting a slight upward pressureon it with your involve the use of either a mechanicalor a hand until it hr.s cleared the hole completely. hydraulic press to force the broach through the Reversing thedirectionof the reamer will part. A considerable amount ofpressure is probably result in damage to the cutting edges required to broach, so bere that the setup is and the hole. rigid and that all applica le safety precautions are strictly observed. A ow even pressure in A straight hand reamer is generally tapered pushingthebroach through thepartwill on the beginning of the cutting edges fora produce the most accurate results with the least distance approximately equal to the diameter of damage to the broach and in the safestmanner. the reamer. You will have to consider thiswhen Do not bring the broach backup through the reaming a hole that does not go all theway hole, push it on through and catch it witha soft through a part. cushion of sefe type. A lubricant is requiredfor broaching most metals. A special broaching oilis Broaching best; however, lard oil or soluble oil will helpto cool the tool, wash away chips and prevent Broaching is a machining process that cutsor particles from.galling or sticking to the teeth. shears the material by forcinga broach through the part in a single stroke. A broach isa tapered, hardened bar, into which has been cut teeth Hand Taps and Dies that are small at the beginning of the tool and get progressively larger toward the end of the Many of the benchwork projects thatyou do tool. The last several teeth will usually be the will probably have eitheran internally or an correct size of the desired shape. Broachesare externallythreadedpartinthedesign available to cut round, square, triangular and specifications. The majority of the threadscut hexagonal holes. Internal splines andgears and on a benchwork project are made with either keyways can also be cut usinga broach. A hand taps, in the case of externally threaded keyway broach requires a .bushing that will fit parts, or hand dies for internally threaded parts. snugly in the hole of the part and hasa The use of these two cutting tools hascome to rectangular slot in it to slide the broach through. be considered as a simple skill requiring littleor Shims of different thicknessesare placed behind no knowledge of the tools and no preplanning of

3-26 Chapter 3LAYOUT AND BENCHWORK

the operation to be performed. It is true that the inch. A taper, or starting tap (figure3-35), has 8 operations are simple, but only afterseveral to 10 of the beginning teeth that factors concerning the correct are tapered. selection and The taper allows each cutting edgeor tooth to operational procedures of the tools havebeen cut slightlydeeperthan the one before it. Thil studied and practiced. Taps and dies are fast and permits an easier starting for the tap andexerts a accurate cutting tools thatcan make a job much minimum amount of pressure against .the easier andwillproduce tool. anexcellentend The next several teeth after thetaper ends are at prcduct. The information given in thefollowing the full designed size of thetap. They remove paragraphs will provide the generalknowledge only a small amount of materialand help to and operational factors tostart you in the leave a fine finish correct ase of taps and dies. on the threads. The last few teeth have a very slight backtaper that allows the tap to clear the final threadscut without TAPS.Hand taps (figure 3-35)are precision rubbing or binding. The plug cutting tools which usually have three tap has 3 to 5 of or four the beginning teeth tapered andthe remaining flutes and a squareon the end for placing a tap length has basically the wrench to turn the tap. Taps same design as the taper are made from tap. The bottoming tap has only 1to 1 1/2 of either hardened carbon steelor high-speed steel and are very hard and brittle. the beginning teeth tapered. Sincethe greatest They are easily amount of material is removed by thetapered broken or damaged when treatedrough or teeth, it is always advisable to begin forced too quickly through the tapping a hole. operation with the tape:,or starting tap. If the Taps for most of the different threadforms, hole being tapped goes all theway through the described later' inthis manual, are available material, the taper tap is usually theonly one either as a standard stock itemor can be special required. If the hole isa blind one, or does not orderedfromatapmanufacturer.The go all the way through the material, all three information in this section includesonly the taps will be required. The taper tap willbe used most commonly used thread forms, th^Unified first, followed by the plug tap, and thefinal pass thread and the American Nationalthroad. Both will be made with the bottomingtap. ofthesethreadsystems havea 60-degree ncluded angle or V form. Standard Sizes and Designations.Thesize of a tap is markedon the shank or the smooth Taps usually come ina set of three for each area between the teeth and the square iifferent diameter and number of on the threads per end. The numbers and lettersalways follow the same pattern and are simple to understand.As an example, the marking 3/8- 16 NC (fig. 3-35) means that the diameter of the tap is 3/8 inch and that it has 16 threadsper inch. The NC is a TAPER symbol indicating the thread series. Inthis case, the NC stands for the American NationalCoarse Thread Series.

Some of the morecommon thread series PLUG symbols are NE, American NationalFine; NS, AmericanNational Special; NEF, American National Extra Fine; NPT, AmericanNational Standard Tapered pipe. A "U" placedin front of one of these symbols indicates __the UNIFIED BOTTOMING THREAD SYSTEM,a system that has the same basic form as the American Nationaland is interchangeable withit,differing mainly in 11.5 tolerance or clearance. These threadsystems will Figure 3-35.Set of taps. be covered in more detail inchapter 9. If an LH

3-27

k. MACHINERY REPAIRMAN 3 & 2

appears on the marking after the thread series Tapping Operations.The first step in symbols, the tap is left-handed. any successful tapping operation is theselection of The next group of markings usuallyfound the correct size tap with sharp, unbrokencutting on taps refers to the method of producing the edges on the teeth. A dull tap willrequire threads on the tap and the tolerance ofthe taP. excessive force to produce the threadsand As an example, in the marking G 114(fig. 3-35) increases greatly the chance of the tap breaking the G indicates that the threadswere ground on and damaging the part being tapped..A dull tap thetap. The greatest majority of thetaps can also produce ragged, torn and undersize manufacturedtodayare ground. The /next threads, leading to a damaged part. symbol, 114, refers to the toleranceof the tap. The H means that the tap hasa pitch diameter The tap drill or the size of the holethat is that is above (HIGH) the basicpitch diameter made for the tap is very important if thecorrect for that size tap. An Lmeans that the pitch fit is to be obtained. Ifa hole were to be drilled diameterisunder (LOW) thebasicpitch that was equal in size to the minor,or smallest, diameter for that size tap. The numberfollowing diameter of the tap, a 100% thread height would the H or L indicates the amount oftolerance in result. To tap a hole this size wouldrequire increments of 0.0005 inch. In the exampleH4, excessive pressure and breakage couldoccur, the pitch diameter is a maximum of0.002 inch especially with a small tapor a material that is (4 X 0.0005) above the basic pitchdiameter. In hard.Unlessablueprint or other design the case of an L, the amount is underthe basic references indicate differently,a 75% thread pitch diameter. A number of 1 through10 can height is usually considered adequate andis be found on taps. This tolerance limitsymbol actually only about 5% less in terms ofstrength plays an important part in obtainingthe correct or holding power than a 100% thread height. In fit for a given class of threads. Threadclasses some of the less critical jobs, it is possible to will be covered later in this manual. have a 60% thread height withouta significant loss in strength. Theonlydifferenceinthesizeand designation markings for taps thatwill probably There are two simple formulas that be found in Navy machine shops may be is in machific applied to calculate the tap drill size forany size screw diameter taps, or numbered tapsas they tap. The simplest and the one most often used are often called in the shop. Instead of the will produce a thread height ofapproximately diameter being represented bya fraction, a 75%. Itis as follows: DRILL SIZE number of 0 through 14 is used. You = TAP can easily DIAMETER MINUS ONE DIVIDED BYTHE convert these numbers to a decimalequivalent NUMBER OF THREADS PER, INCH: by remembering that the number 0tap has a 1 diameter of 0.60 inch and each tap number after (DS = TD N). As an example, the drillsize for that increases in diameter by 0.013 inch.As an a 1/4 - 20 NC tap is figured as follows: example: Step 1: DS = 1/41/20 Size 0 = 0.60 inch dia. Step 2: DS = 0.250 -0.050 Size 3 = 0.99 inch dia.[0.060 + (3 X 0.013)] Step 3: DS = 0.200 in. Size 14 = 0.242 inch dia.[0.060 + (14 X The nearest standard size drill 0.013)] would then be selected to make the hole. In thiscase, a number 8 drill has a diameter of 0.199 in. and A typical Marking on a tap might be 10.24 a number UNC, 7 drill has a diameter of 0.201 in.Cfniess the size indicating a diameter of 0.190 inch, 24threads differences are very great, it is per inch, and a Unified National Coarse thread more effective to select the larger drill sizeor the number 7 drill series. for this tap.

3-28 Chapter 3LAYOUT AND BENCHWORK

The second formula, although slightlymore center of the hole. When this is completed, difficult, allows for a selection of the desired insert the tap drill into the drilling machineor percentage of thread height. To use it, you must drill press and drill the hole. If the hole isvery know the straight depth of the thread. Youcan large, you should use a drill several sizes below obtainthisdatafromvariouschartsin the tap drill size to prevent an out-of-roundor handbooksformachinists or by using the excessively oversized hole. Do NOTmove the formulas in chapter 9 of this manual. It isas part when making the various tool changes. follows:DRILL SIZE = TAP DIAMETER MINUS THE DESIRED PERCENTAGE OF The hole is now ready to be tapped. Some THREAD HEIGHT TIMES TWICE THE taps have a center hole in the shank that will fit STRAIGHT DEPTH. As an example, ifa 60% over the point of a center. If this is the case and thread height is desired fora 1/4 - 20 NC tap, the setup will allow it, place a center in the drill the drill size is figured as follows: press without moving the part; place a tap wrench over the square shank, turn the center Step 1: DS = 1/4- .60 X 2(0.032) into the center hole on the tap (fig. 3 -36) .and slowly turn the tap while applyinga slight Step 2: DS = 0.250 - .60 X 0.064 downward pressure on the center to help guide the tap. If a center cannot be used, align thetap Step 3: DS = 0.250- 0.038 as close as possible by eye and make 2 or 3 turns with the tap handle. Remove the tap handle and Step 4: DS = 0.212 in. place a good square on the surface of the part (if machined flat) and bring it into contact with the The nearest standard size drill to 0.212 inchis a shank of the tap at two points 90° from each number 3 drill which has a diameter of 0.213 other (fig. 3-36). If the tap is not perpendicular inch. A word of caution about drilling holes for or square with the surface at both points, back it tapping 'is important at this point. Even if the drillis ground perfectly,the part is rigidly clampedandthedrillingmachine has no CHUCK looseness, the drilled hole can be expected to be TAP CENTER oversized. In the case of the number 7 and the WRENCH number 3 drills selected in the two examples ,given,, thedrilledholeswillprobablybe approximately 0.003 to 0.004 inch oversize. This shouldbe consideredin planning the operation. Additional informationon drilling holes is in chapter 5. TAPPING WORK IN A DRILL PRESS After you have selected the tap and tap drill, you must securely clamp the part to be tapped In a or drill press table as dictated by the parts size and shape. You MUST be sure that the part cannot vibrate loose and be thrown out of the vise or off the drill press table. Whena twist drill ,driven by a geared motor digs inor binds in a part, a great amount of force Is exerted against, the part. You could lose a fingeror hand, break a leg, or worse if this happens. It is best to start CHECKING TAP the drilling operation witha small drill or a WITH A SQUARE center drill (described later in this manual) by aligning the drill point as close as possible to the 28.325 Center punch mark you made to locate the Flgun(3-38.-8tartIngs tap.

3-29 MACHINERY REPAIRMAN 3 & 2

out and start over. When the tap issquare, begin The size of a die is usually marked ',turning the tap wrench slowly. on the After making trailingface(thesidethatisupduring two or three turns, turn the tap backwardsto threading) and follows thesame format as a tap. break the chips and help clear themfrom the A die marked 5/8- 11 NC means that the part path of the taps. Proceed with this untilthe tap threadedwill have a 5/8-inch diameter, bottoms out; then place the next 11 tap in the set threads per inch and is of the AmericanNational in the hole and repeat the tapping procedure.If Coarse thread series. The G, H, L, and associated the hole is blind, remove thetaps often to clear numbers found on a tapare not normally the chips from the bottom. marked on a die because theyrepresent a fixed tolerance and the die is adjustable. It is often necessary toremove burrs from around a hole that has been tapped. Do this with The steps involved in threadinga part with a a file, by slowly hand-spinning a larger twist drill die are similar to those fora tap. The part to be in the hole or by usinga . threaded should havea ground or cut on the end to help in starting the die square with A cutting oil should be used in mosttapping the part. Select the correct die and insertit in operations.Thereareseveralcommercial thediestockwith the products longest tapered side availablethatgreatly enhance the opposite the square shoulder. Apply cutting oil quality of thread produced. A heavy cutting oil and place the die over the part bygrasping the with either a sulfur, mineral oilor lard oil base diestock in the middle withone hand. Turn the is available in the supply system. Ifno other cuttingoilisavailable, a heavy mixture of soluble oil will be acceptable.

DIES.Band threading diescome in various styles, including unadjustable solidsquare and round shaped dies and adjustable singleand two-piece dies. The mostcommon die used in Navy machine shops is the adjustablesingle pieceor roundsplitdie(fig.3-37). The adjustable round split die isa round disk-shaped tool which has internal threads andusually four holes or flutes that interrupt the threadsand present four sets of cutting edges. The die hasa groove cut completely through one side anda ADJUSTING LOCKING setscrewtoallowfora small amount of SCREW HOLE expansion and contraction of the die.This ROUND SPLIT DIE feature permits an adjustment for takinga rough A and a finish cut on particularly hardor tough metals and also allows for slight adjustmentsto obtain a close fit with a matednut or other internally threaded part. There isa difference in the two sides of the diethe startingside has about 3 full threads tapered and the trailingside has about 1thread tapered. To prevent damage to the die and the threads being cut,the die THREE SCREW DIESTOCK should always be started with thegreatest taper leading. The die is held ina diestockfig. 3-37), B a tool which has a circul, recess to hold the die andthreesetscrewsthatfitintosmall indentations in the outside diamet 11.5.2-6 r of the die. Figure 3.37. Die and diestock.

3-30

i Chapter 3LAYOUT AND BENCHWORK

die several turns, then look carefullyat the die closely to ensure that no fragments of the tapor and the part to ensure that theyare square. jagged threads remain to cause problems when Threads that are deeper on one side than the another tap is used to finishor clean up the other indicate a misaligned die. Turn the die threads. about three turns and then back it offone turn to break the chip. Aftthe die has been run Another method is to use a punch and apply down part far enough to get a few full depth sharp blows to the broken tap. This method will threads, remove it from the part and check probably be used when the tap is broken below the the surface of the part. Always fi+ with the part that will mate with it.Make any wear safety adjustml,its necessary at this time. Replace the goggles and a face shield to protectyour face die on the part and continue threading until the and eyes from flying fragments. Do not allow desired thread length is reached. If the threads anyone to stand near you while doing this type are being cut to L .boulder, you may turn the operation. The punch should be smaller than the tap to permit placing the point on selected die over and cut the last 2 or 3 threads withthe areas short tapered side. of the tap. As a fragment of the tap isbroken away, remove it from the hole. This method will Removing Broken Taps probably cause serious damage to the threaded hole when the punch strikes the threads,or an Removing a broken tap is usuallya difficult oversized condition can result from forcing the operation and requires slow, deliberate actions tap around in the hole. You should besure that to remove it successfully without damaging the thereisan approved method of repair or modificationof part involved. There is no single method thatcan thethreadedholebefore be applied to all the different circumstancesyou undertaking this method of removal. may experience. The following information It is sometimes possible to welda stud to the describes briefly some of the methods that have top of a tap that is broken off below the surface. proven" to be effective. You will need to evaluate The tap diameter must be large enoughfor the particular problem and attempt removal insertion of both the stud and the rod in with the method that will work best. the hole without running the risk of havingthe welding rod touch or splatter the threads. There A tap that has broken and has at least 1/4 are materials that can be used to help protect inchleftprotrudingabovethepartcan the threads. Unless youare an accomplished sometimes be grasped by vise grips and removed. welder, do not attempt this job. Discuss it witha Use a scribe first to removeas many as possible Hull Maintenance Technician (HT) and let him of the chips from the hole and the flutesof the do it. A more even pressurecan be applied in tap. Do not use compressed air toremove the, removing the tap if a square is groundon the top chips because there is alwaysa chance that a of the stud so that a tap wrenchcan be used. small chip will be blown into eitheryour eyes or The heat generated by the weldingprocess could someone's near by. Apply penetrating oil around expand the tap slightly so that when it cooled the threads if possible. Usea small hand grinder and contracted, the tap may have loosened to shape the end of the tap to providea good slightly. On the other hand, the tapmay bind grip for the vise grips. If theyare permitted to even more and the structure and condition of sliponthetap,additionalfragmentswill the surrounding metal could be changed. probably break away, givingyou less surface to If the tap is broken off below the surface of grasp. Apply a slow, even force. Excessive force the part, a tool called a tap extractor (fig. 3-38) or jerky movements will cause more damage. can be used to remove it. You should try this You may need to carefully rockor reverse the method first as it does no damage to the threads. direction in which you are turning the tap in Tap extractors ave available for each of the orderto freeit.This is especiallytruein standard diameter tapsover about 3/16 inch. As beginning the removal. Use a lubricant once the you see in figure 3738, the tap extractor hasa tap has been loosened in the hole. When the tap square end for using a tap wrench and sliding has been removed, examine the hole and threads prongs or fingers that fit into e,ch of the flutes

3.31 A MACHINERY REPAIRMAN 3 & 2

is effective primarily on steel parts. When mixing BROKEN SLIDING theacidsolutionaddtheacidtothe TAP PRONG COLLAROLLAR premeasured amount of water. The procedure of adding the acid to the water isa safety measure because some acids react violently when water is added to them. You shouldwear chemically resistant goggles, a face shield, rubberor plastic BOTTOM SQUARE COLLAR gloves, and an apron. Nitric acidcan damage SHANK your eyes, burn your skin and eat holes in your clothes.Ifanyacidgetson yourskin, 4.37:44.191 immediately flush with water for at least 15 Figure 3.38. Tap extractor. minutes and seek medical attention. You will use nitric acid often in identifying metals and you should treat each occasion as seriously.as on the tap. The upper collar is secured in place thefirst,strictlyobservingeverysafety by setscrews while the bottom collar is freeto precaution. move. Position the bottom collar as close as possible to the tap of the hole to prevent the There is one other method for removing sliding prongs from twisting. The best resultsare broken taps that is used primarilyon tenders, obtained from this tool when the slidingprongs repair ships and shore based repair activities.It have a minimum amount of unsupported length involves the use of a special machine (metal exposed. Apply a slow, evenpressure to the tap disintegrator), electrodes and a coolant. Any wrench in removing the tart. metalthatwillconduct electricitycan be worked with this machine. The action ofthe In all of the methods listed, remove all chips electrode and the coolant combined createa prior to beginning the removalprocess. There hole through the part that is equal in size to the are several methods for helping to free the tap diameter of the electrode. Thereare portable that can be used withany of the removal models available; however, most models either methods if the particular situation lendsitself to have their own cabinet or theyare used in a drill their use. As previously mentioned, penetrating press. Detailed information on this method can oilcanbe appliedaround thethreads. A be found la'r in this manual. controlled heat may be .applied to thearea surrounding the tap to cause expansion. Bevery careful to limit the heat so that the tap doesnot Classes of Fits begin to expand also. Since most tapsare made from high-speed steel,this probably will not The following informationconcerns fit as occur, but do not overlook the possibility. You applied to plain cylindrical parts suchas sleeves, must also consider damage to the part from bearings,pumpwearingringsandother heat. If the part is very big and hasa large mass nonthreaded round parts that fit together. Fit is of metal in the immediatearea, the heat will defined as the amount of tightness orslooseness carry to the surrounding area rapidly, preventing betweentwomatingpartswhencertain adequate heat and expansion where it is needed. allowances are designed into them. As defined earlier in this chapter, an allowance is the total Anothermethod,onethatmustbe difference between the size ofa shaft and the conducted under strict safety conditions, isto hole in the part that fits over it. This allowance apply a solution of 1 part nitric acid and 5parts and the resulting fit can bea clearance (loose) water tothe threaded hole. The nitric acid fit, an interference (tight) fit,or a transitional solution will gradually eataway some of the (somewhere between loose and tight) fit. These surface metal and loosen the tap. After the acid three general types of fitsare further identified solution has worked for a little while, pour it by classes of fits,with each class havinga out and rinse the part thoroughly. This method different allowance basedon the intended use or

3-32 Chapter 3LAYOUT AND BENCHWORK

functionofthepartsinvolved.A brief although they may rotate togetheras part of a description of each type fit will be given in the largeruser:111y.Theallowancesusedas following paragraphs. Any good handbook for example.. i4.tilts following descriptions of the has, complete charts with detailed various cos represent the sum of the tolerances information on each individual class of fit. The of the e, err al and internal parts. To achieve majority of equipment repaired in Navy machine maximumstandardizationandtopermit shopswillhavethedimensionalsizesand common size reamers and other fixed sized allowancesalreadyspecifiedineitherthe boring toois to be used as muchas possible, it is manufacturer's technical manual, NAVSHIPS' best to use the unilateral tolerance method Technical Manual, or the appropriate Preventive previously explained and consultone of the class Maintenance System Maintenance Requirement of fit charts in a handbook for machinists. Card,whichisthepriorityreference on maintenance matters. Locational clearance fits are broken down into 11 different classes of fits. The game basic CLEARANCE FITS.Clearancefits or diameter with a class 1 fit ranges from a zero running and sliding fits as they are often called, allowance to a clearance allowance of +0.0012 provide a varying degree of clearance (looseness) inch, while a class 11 fit ranges froma clearance depending on which one of the nine classes is allowance of +0.014 to +0.050 inch. Thenearer selected for use. The classes of fitsrange from a part is to a class 1fit, the more accurately it class 1 (close slidingfit), which permits' a can be located' without use of force. clearance allowance of from +0.0004 to +0.0012 inch on mating parts with a 2.500 inch basic Locational transition fits have six different diameter, to class 9 (loose running fit), which classesprovidingeitherasmall amount of permits a clearance allowance of from +0.009to clearanceoraninterferenceallowance, +0.0205 inch on the same parts. Even fora basic depending on the class of fit selected. diameter, The thesmall (2.500 inch)clearance 2.500-inch basic diameter in a class Ifit ranges allowance from a class1 minimum to a class 9 from an interference allowance of -0.0003 inch maximum differs by +0.0201 inch. As the basic to a clearance allowance of +0.0015 inch whilea diameterincreases,theallowanceincreases. class 6 fit ranges from an interference allowance Although the class of fit may not be referenced of -0.002 inch to a clearance allowanceof on a blueprint, the dimensions given for the +0.0004 inch. The interference allowance fits mating parts are based on the service performed may require a very light pressure to assemble or by the parts and the specific conditions under disassemble the parts. which they operate as described in each ofthe classes of fits. Some parts that fall withinthese Locational interference fits are divided into classes of fits are a shaper ram (close sliding),a five different classes of fits, all of whichprovide babbitt-lined bearing, and pump wearing rings an interference allowance of varying amounts. A (loosedremoval). class I fit for a 2.500-inch basic diameterranges from an interference allowance of -0.0001to TRANSITIONAL FITS.Transitionalit -0.0013 inch, while a class 5 fitranges from an aresubdivided intothreetypes known as interferenceallowance of from -0.0004 lb locational clearance, locational transition and -0.0023 inch. These classes of fitsare used when looational interference fits. Each of these three parts must be located very accurately while subdivisions contains different classes of fits maintaining alignment and rigidity. Theyare not which'provideeitheraclearanceoran suitableforapplications where one part is interference allowance,dependingonthe subjected to a force that causes it to turnon the intended use and class, selected. All of the classes other part. of fits in the transitional categoryare primarr! intended for the assembly and disassembly of INTERFERENCE FITS.Therearefive stationary parts. Stationary in thissense means classes of fits within the interference type.They that the parts will not rotate against each other are allfits that require force to assembleor

3-33 MACHINERY REPAIRMAN 3 & 2

disassemble parts. These fits are often called recommended decreases as the diameter of the force fits and in certain classes of fits theyare partincreases.Thedimensionaldifference referred to as shrink fits. Using thesame basic, between the inside and outside diameter (wall diameter as an example, the class 1fit ranges thickness) also has an effect on the interference from an interference allowance of -0.0006to allowance. A part that has large inside and -0.0018 inch and a class 5 fitranges from an outside diameters and a relatively thin wall interference allowance of -0.0032 to -0.0062 thickness will split if installed with an excessive inch. The class 5 fit is normally considered to be interference allowance. All of these variables a shrink fit class because of the large amounts of must be considered before you select a fit when interference allowance required. there are no blueprints or other dimensional references available. A shrink fit requires that the part with the external diameter be chilled or that the part Hydraulic and Arbor Presses with the internal diameter be heated. Youcan chill a part by placing it in a freezer, packing it Hydraulic and arbor pressesare used in in dry ice, spraying it with CO2 (do notuse a many Navy machine shops. They are used to CO2 bottle from a fire station) or by submerging forcebroaches through parts, assemble and it in liquid nitrogen. All of these methods except disassemble equipment with force fitted parts, the freezer are potentially dangerous, especially and many other shop projects. the liquid nitrogen and should NOT be used until all applicable safety precautions have been Arbor presses are usually bench mounted with a gear and gear rack arrangement. They reviewed and implemented. When a partis are chilled,itactually shrinks insize a certain used for light pressing jobs, suchas pressing arbors or into a part for machiningor amount depending on the type of material, forcing a small broach through design, chilling medium, and length of time of a part. exposure to the chilling medium. You can heat a Hydraulic presses can be either verticalor part byusinganoxyacetylenetorch,a horizontal,althoughtheverticaldesignis heat-treating oven, electrical strip heaters or by probably more common andversatile. The submergingitina heated liquid. As with pressurethat a hydraulic press can generate chilling, all applicable safety precautions must ranges from about 10 to 100 tons in most of be observed. When a part is heated, it expands in the Navy machine shops. Thepressure can be size,allowingeasier assembly.All materials exerted by either a manually operatedpump or expand adifferent amount per degree of an electrohydraulic pump. temperatureincreased.This iscalledthe Regardless of the type of press equipment coefficientof expansionof ametal. Most used, be sure that it is operated correctly. The handbooks for machinists include a chart of the only method for determining the amountof factors and explain their use. It is important that pressure exerted by a hydraulic press is by you calculate this information to determine the watching the pressure gage. A part being pressed maximum temperatureincreaserequiredto can reach the breaking point without any visible expand the part the amount of the shrinkage indicationthattoo much pressureisbeing allowanceplusenoughclearancetoallow applied. When usingthepress,you must assemble.Overheatinga partcancause considerthe interference allowance between permanentdamageand produceso much mating parts; corrosion and marred edges; and expansion that assembly becomes difficult. overlookedfasteningdevices,suchaspins, A general rule of thumb for determining the setscrews, and retainer rings. amount of interferenceallowance onparts To prevent damage to the work, observe the requiring a force or shrink fitis to allow ap- following precautions when using the hydraulic proximately 0.0015 inch per inch of diameter press: of the internally bored part. Thereare many variables that will prohibit the use this general Ensurethatthe workisadequately rule.The amount of interference allowance supported.

3-34 Chapter 3LAYOUT AND BENCHWORK

Place the ram in contact with the work torches; goggles withfilterlenses,for eye by hand,sothatthe workispositioned protection; and gloves for protection of the accurately in alignment with the ram. hands. Flame-resistant clothing is worn when necessary. Use a piece of brass or other material (preferably slightly softer than the workpiece) Acetylene (chemical formula C2 H2) is a fuel between the face of the ram and the work to gas made up of carbon and hydrogen. When preventmutilationtothesurfaceofthe burned with oxygen, acetylene produces a very workpiece. hot flame having a temperature between 5700° and 6300°F. Acetylene gas is colorless, but has a Watch the pressure gage. You cannot distinct, easily recognized odor. The acetylene determine the pressure exerted by "feel." If usedonboardshipisusuallytake"from excessivepressureisrequired,releasethe compressed gas cylinders. pressure and doublecheck the work to find the Oxygen is a colorless, tasteless, odorless gas cause. which is slightly heavier than air. Oxygen will notburnbyitself,butitwill When pressing support partstogether,use a combustion when combinedwith,other gates. lubricant between the mating parts to prevent You must be extremely careful to ensure that seizing. compressedoxygendoesnotbecone contaminated with hydrogen or hydrocarbon Informationconcerningthepressure gases or liquids, unless the oxygen is controlled required to force fit two mating parts together is by such means as the mixing chamber of a torch. available in most handbooks for machinists. The A highly explosive mixture will be formed if distance that the parts must be pressed usually uncontrolledcompressedoxygenbecomes increases the required pressures, and increased contaminated. Oxygen should NEVER come in interference allowance require greater pressures. As a guideline for force-fitting a cylindrical contact with oil or grease. shaft, the maximum pressure, in tons, should The gas r ina cylinder must be not exceed 7 to 10 times the shaft's diameter in reduced to a .. :+ -king ensure before it inches. canbeused. t pressurereductionis I accompliqhe 1by w LC REGULATOR or Oxyacetylene Equipment reducing Regu,,ttors that control the flow ofgasa ornthe:ylinderareeitherthe As a Machinery Repairman, you may have to single-star of tht; ,lo.ole-stage type. Single - stage use an oxyacetylene torch to heat psi isto regulators q:J1.1Cfl thressure of the gas in one expand them enough to permit assembly or step; two-!..4v cm, .1.ors do the same job in two disassembly. This should be done with great steps, or 4:ss adjustment is gevarally care, and only with proper supervision. The necessary N wa-stage regulators are operation of the oxyacetylene, torch 7 as used in heating parts only is explained in this chapter The hose c.rmnection between the Orrh end with safety precautions which must be observed theregulators isstrong,nonpur,qs, when using the torch and related equipment. ficiently flexible and light to max- +cr1/4:1t movenents eaay. The hose is made to whilst/bid Oxyacetyleneequipmentconsistsofa high, internal pressures, and tl'e rubber from cylinder of acetylene, a cylinder of oxygen, two which it is made is specially t ..at-d to remove .agulators, two lengths of hose with fittings, a sulfurtoavoidthedanger cf spontaneous welding torch with tips, and either a cutting combustion. Welding hose is available in various attachmentofa separatecuttingtorch. sizes, depending upon the size of w,)tk for which Accessones include i spark lighte to light the it is intended. Hose used for light work is 3/16 torch; an vddaratu. v inch to fit the various or 1/4 inch in diameter, and it has one or two connectionsonlegulators,cylutders,and plies of fabric. For he le duty welding and MACHINERY REPAIRMAN 3&

cutting operations, hose withan inside diameter Each cliff:if:0 type of torch and of 1/4 or 5/16 inch and threeto five plies of tip size fabric is used. Single hose requires a s:,(..:Atic workingpressure to operate comes in lengths of properly and safely. These 12 1/2 feet to 25 feet.Some manufacturers pressures are set by adjustingtheregulargagestothe make a double hose which conformsto the same setting general prescribe bychartsprovidedbythe specifications.The hosesusedfor manufacti,,, acetylene and oxygen are thesame in grade but they differ in color and havedifferent type of P113(EDWIE FOR SETTINGUP threads on the hose fittings. Theoxygen hose is GREEN and the acetylene hose 0 XYACMYLENEEQUIPMENT.Takethe is RED. The followin stepsinsettingup oxyacetylene oxygen hose has right hand threads andthe equipme,i : acetylene hose has left hand threadsfor added protection against mixing the hoseup during connection. 1. s. Aire the cylindersso that they cannot be upet. '1'stmove the protectivecaps. The oxyacetylene torchisused to mix 2. ('rack the cylinder dIves slightlyto blow oxygenandacetylenegasintheproper out i,ny dirt that may be in thevalves. Close the proportions and to control the volume ofthese valves wipe the connections witha clean gases burned at the torch tip. Torches havetwo etc. I:1 needle valves, one for adjustingthe flow of oxygen and the other for adjusting the flow of 3. Coiriect theetylene pressure regulator tothe,::F' laic;ylinder andthe oxygen acetylene.Inaddition,they have a handle presst. (body), two tubes (one for reg but,- the oxygen cylinder. Using oxygen and one for theappropriate acetylene), a mixing head, anda tip. Torch tips wrench provided with the are made from a snecial copper alloy which equipment tigt, col tie connectingnuts. dissipates heat (less than 60% copper)and are 4. Conr.ecs the red hoseto the acetylene available in different sizes to handlea wide range regulator and thegreen hose to the oxygen of plate thicknesses. regulator. Tiir,hten the connectingnuts enough Torch tips and mixers made bydifferent to previ.nital: age. manufacturers, differ in design. Some makes of Back off on the regulatorscrews, and torches have an individual mixinghead or mixer th.rl open the cylinder valves for each size of tip. Other slowly. Open the makes have only one ar..tylene valve 1/4 to 1/2turn. This will allow mixer for several tip sizes. Tipscome in various du adequate flow of acetylene and thevalve can types. Some areone - pied, hard copper tips. u .turned off quickly in Others an emergency. (NEVER aretwo-piecetipsthatincludean open the. acetylene cylinder', valve extension tube to make connection more than between the 1 1/2 turns.) Open theoxygen cylinder valve all tip and the mixing head. Whenused with an ex. the way to eliminate leakage tension tube, removable tips around the stem. are made of ha -s' (Oxygenvalvesaredouble seatedor have copper, brass, or bronze. Tip sizesare designated diaphragms to prevent by numbers, and each manufacturer leakage when open.) has its own Readthehigh-pressuregagetocheck the arrangement for classifying them. Tipshave pressure of each cylinder. different hole dian) :tern. No matter wlA typeor size tip you select, 6. Blow out the oxygen hose byturning the the tip must be )..eptcilan. Quite often:he regulator screw in and thenback out again. If it orifice becomes clogged. Whenthis happens, the is necessary to blowout the acetylene hose, do flame will not burn properly.Inspect the NI it ONLY in a well-ventilate//place that is free before you use it. If thepassage is obstructed, from sparks, flames,or othe !possible sources of you can it with wire tipcleaners of the ignition. proper diameter, or witi soft copper wire. Tips 7. Connect the hosesto the torch. Connect should not be cleaned withmachinist's drills or oth.r sharp instruments. the red acetylene hoseto the connection gland that has the needle valve markedAC or ACET,

1.4 3.36 II) Chapter 3LAYOUT AND BENCHWORK

Connectthegreenoxygenhosetothe greenish tinge of acetylene at its tip, nor is there connectiongland that has the needle valve an excess of oxygen. A neutral flame is obtained marked OX. Test all hose connections for leaks by gradually openingthe oxygenvalveto by turning both regulator screws IN, while the shortentheacetylene flame until a clearly needle valves are closed. Then turn the ,egulator defined inner luminous cone is visible. This is screws OUT, and drain the hose by or ening th3 the correct flame to use for many metals. The needle valves. temperature at the tip of the inner cone is about 8. Adjust the tip. Screw the +no the 5900°F, while at the extreme end of the outer mixing head and assemble in tht. cone it is only about 2300°F. This gives you a Tighten by hand and adjust to the proper angle. chance to exercise some temperature control by Secure this adjustment by tightening with the moving the torch closer or farther from the wrench provided with the torch. work. 9. Adjust the working pressures. Adjust the acetylene pressure by opening the acetylene EXTINGUISHING THE OXYACETYLENE torch needle valve and turning the regulator FLAME.To extinguish the oxyacetylene flame screwtotheright.Adjusttheacetylene and to secure equipment after completing a job, regulator to the required working pressure for or when work is to be interrrupted temporarily, theparticulartipsize.(Acetylenepressure you should take the following steps: should NEVER exceed 15 psig.) 10. Light and adjust the flame. Open the acetylene needle valve on the torch and light the 1.Close the acetylene needle valve first; acetylene with a spark lighter. Keep your hand thisextenguishestheflameandprevents out of the way. Adjust the acetylene valve until flashback. (Flashback is discussed later.) Then the flame just leaves the tip face. Open and close the oxygen needle valve. adjust the oxygen valve until you get the proper 2.Closebothoxygenandacetylene neutral flame. Notice that the pure acetylene cylinder valves. Leave the oxygen and acetylene flame which just leaves the tip face is drawn regulators open temporarily. back to the tip face when the oxygen is turned on. 3. Open the acetylene needle valve on the torch and allow gas in the hose to escape for 5 PROCEDURE FOR ADJUSTING THE to 15 seconds. Do NOT allow gas to escape into FLAME.A pure acetylene flame is long and asmallorclosed compartment. Closethe bushy and has a yellowish color. It is burned by acetylene needle valve. the oxygen in the air, which is not sufficient to 4. Open the oxygen needle valve on the burn the acetylene completely; therefore. the torch. Allow gas in the hose to escape for 5 to flameissmoky, producing a soot of fine, 15 seconds. Close the valve. unburned carbon. The pure acetylene flame is unsuitable for use. When the oxygen valve is 5.Closebothoxygenandacetylene opened, the mixed gases burn in contact with cylinder regulators by backing out the adjusting the tip face. The flame changes to a bluish-white screws until they are loose. color and forms a bright inner cone surrounded by an outer flame envelope. The inner cone Follow the foregoing procedure whenever develops the high temperature required. work is interrupted for an indefinite period. If work is to stop for only a few minutes, securing The type of flame commonly used for cylinder valves and draining the hose is not heating partsisa neutral flame. The neutral necessary. However, for any indefinite work cameis produced by 1,urning one part of stoppage, follow the entire extinguishing and oxygen to one part of acetylene. Together with securingprocedure.Forovernightwork the oxygen in the air,it produces complete stoppage in areas other than the shop, it is a Combustion of theacetylene. The luminous good idea to remove pressure regulators and white coneiswell-defined and thereisno torch from the system and to double check the

3.37, . MACHINERY REPAIRMAN 3& 2

cylinder valves to makesure that they are closed securely. but have a pitch that is differentfrom the pitch of the threads on theoxygen cylinder valve outlets. SAFETY: OXYACETYLENE If thethreads do not match, the EQUIPMENT connections are mixed. When you are heating withoxyacetylene Always use the correct tipor nozzle and equipment, certain safety precautionsmust be the correct pressure for the observed to protect personneland equipment particular work involved. This informationshould be taken from frominjurybyfireorexplosion.The tablesorworksheetssuppliedwiththe precautions which follow applyspecifically to equipment. oxyacetylene work. Use only approved Do NOT allow acetylene andoxygen to apparatus that has accumulate in confinedspaces. Such a mixture is been examined and tested forsafety. highly explosive.

When cylinders are inuse, keep them far Keep a clear space betweenthe cylinder enough away from the actualheating area so and the work so that the they will not be reached by cylinder valves may be the flame or sparks reached quickly and easily ifnecessary. from the object being heated. When lighting the torch,use friction NEVER interchange hoses,regulators, or lighters, stationary pilot flames,or some other other apparatus intended foroxygen with those suitable source of ignition. The intended for acetylene. use of matches may cause serious hand burns. Do NOTlight a torch from hot metal. Whenlighting the torch, Keep valves closedon empty cylinders. open the acetylene valve first and ignitethe gas with the oxygen valve closed.Do NOT allow Do NOT stand in front ofcylinder valves unburned acetylene toescape into a small or while opening them. closed compartment.

When a special wrench isrequired to When extinguishing the torch,close the open a cylinder valve,leave the wrench in acetylene valve first and thenclose the oxygen position on the valvestem while the cylinder is valve. being used so that thevalve can be closed rapidly in anemergency. Do NOT use lubricantsthat contain oil or grease on oxyacetylene equipment.OIL OR Always open cylinder valvesslowly. (Do GREASE IN THE PRESENCEOF OXYGEN NOT open the acetylenecylinder valve more UNDER PRESSUREWILL IGNITE than I1/2 turns.) VIOLENTLY. Consequently,oxygen must not be permitted tocome in contact with these materials in any way. Do NOThandle cylinders, Close cylinder valves beforemoving the cylinders. valves, regulators, hose,or any other apparatus which uses oxygen underpressure with oily hands or gloves. Do NOTpermit a jet of oxygen NEVER attempt to forceunmatching or to strike an oily surfaceor oily clothes. NOTE: crossed threads on valve outlets, hose couplings, A suitable lubricant foroxyacetylene equipment or torch valve inlets. The threadson oxygen is glycerin. regulator outlets, hose couplings,and torch valve inletsareright-handed; for acetylene,these threadsare NEVER use acetylenefrom cylinders left-handed.Thethreadson without reducing the acetylene cylinder valveoutlets are tight-handed, pressure through a suitable pressure reducing regulator. Acetyleneworking 3-38 Chapter 3LAYOUT AND BENCHWORK

pressures in excess of 15 pounds per square inch momentary burning back of the flame into the must be avoided. Oxygen cylinder pressure must torch tip; in a flashback, the flame burns in or likewise be reduced to a suitable low working beyond the torch mixing chamber. A backfire is pressure; high pressure may burst the hose. characterized by a loud snap or pop as the flame goes out. A flashback is usually accompanied by Stowallcylinderscarefullyin a hissing or squealing sound. At the same time, accordancewithprescribedprocedures. theflameatthetipbecomes smoky and Cylindersshouldbestowedin dry, sharp-pointed.When a flashbackoccurs, well-ventilated, well-protected places away from immediately shut off the torch oxygen valve, heat and combustible materials. Do NOT stow then close the acetylene valve. oxygen cylinders in the same compartment with acetylenecylinders.All cylinders should be A flashbackindicatesthat something is stowed in an upright position. If they are not radically wrong either with the torch or with the stowed in an upright position, they should not manner of handling it. A backfire is less serious. be used until they have been allowed to stand Usually the flame can be relighted without upright for at least 2 hours. difficulty. If backfiring continues whenever the torchisrelighted,checkforthesecauses: Do not use the torch to heat material overheated tip, gas working pressures greater without first making certain that hot sparks or than that recommended for the tip size being hot metal will not fall on the legs or feet of the used, loose tip, or dirt on the torch tip seat. operator, on the hose and cylinder, or on any These same difficulties may be thecause of a flammable materials. A fire watch should be flashback, except that the difficulty is present to posted as required to prevent accidental fires. a greater degree. For example, the torch head may be distorted or cracked. Flameproof protective clothing and shaded goggles should be worn by both the operator of In most instances, backfires and flashbacks the equipment and anyone nearby to prevent result,fromcarelessness.Toavoidthese serious burns to the skin or the eyes. A number difficulties, always make certain that (1) all 5 or 6 shaded lens should be sufficient for the connections in the system are clean and tight, heating operations performed by Machinery (2) torch valves are closed (not openor merely Repairmen. loosely closed) when the equipment is stowed, (3) the oxygen and acetylene working pressures These precautions are by no means all the used arethose recommended for the torch safety precautions that pertain to oxyacetylene employed, and (4) the system is purged of air equipment, and they only supplement those before using the apparatus. Purging the system specified by the manufacturer. Always read the of air is especially necessary when the hose and manufacturer'smanualandadheretoall torch have been newly connected or a new precautions andprocedures forthespecific cylinder is incorporated into the system. equipment you are going to be using. PURGING THE OXYACETYLENE Flashback and Backfire TORCH.

A backfire or a flashback are two common 1.Close torch valves tightly, then slowly problems encoutered in using an oxyacetylene open the cylinder valves. torch. 2.Open the regulator slightly. Unless the system is thoroughly purged of 3. Open the torch acetylene valve and allow air and all connections in the system ,re tight acetylenetoescapefor5to 15 seconds, before the torch is ignited, the flame 1: ckely to depending on the length of the hose. burn inside the torch instead of outside the tip. 4.Close the acetylene valve. The difference between the two terms backfire 5.Repeat the procedure on the oxygen side and flashback is this: in a backfire, there is a of the system.

3-39 MACHINERY REPAIRMAN 3& 2

After purging air from thesystem, light the torch as described previously. or larger, and either a square or hexagonshaped head. Bolts are designed to beinserted into holes slightly larger than the diameter FASTENING DEVICES of the fastener. Q A nut is attached to the threadedend, and the mating parts are clamped together.As a general Componentpartsofmachineryand rule, the, width of the head equipment are held together by several across the flats is types of approximately 1 1/2 times thediameter of the fasteningdevices.Thefasteningdevices commonly used by the Machinery threads. The percentage of thebolt that is Repairman threaded ranges from 2 timesthe threaded are classified in three generalgroups: threads, keys, and pins. diameter plus 1/4 inch toa point just below the head, dependingon the intended use. It is best The to use a bolt that hasan unthreaded diameter selectionof thecorrectfastener length slightly less than the4ombined (specified in blueprints, lists ofmaterial blocks, thickness and technical manuals) and of the parts being mated.The overall length the use of an should allow a minimum of 1full thread and a approved installation methodareimportant maximum of 10 threads (space factors in the efficiency andreliability of a piece permitting) to of equipment. Improper protrude above the nut afterthe assembly is use of fasteners will completely torqued down. The leadtoequipmentfailuresandpossible class of fit personnel injuries. normally found on the threads ofbolts and the nuts used with them isa class 2A for the bolt and a class 2B for the Threaded Fastening Devices nut. This class of fit permits an allowanceso that the bolt and nut can be assembled without seizing Bolts, studs, nuts,capscrews, machine screws or galling. and Detailed informationon the different classes of setscrewsarealleitherexternallyor fit foi threads is covered later internally threaded devicesused to clamp or in this manual. secure mating partstogether. Each of the different STUDS.A stud is an externallythreaded typeshasaspecificrangeof fastener with threads applications and is available in on both ends. It can either various sizes, be inserted througha clearance hole and secured designs and material specifications.The most by a nut on each end, common sizes or it can be used in an evolve from theestablished assembly where one part has diameters, threads per inch, and a tapped hole and classes of fits as the second part hasa clearance hole. In the described in the Unified (UNC,UNF) and the latter case, the stud is screwed American National (NC, NF) into the tapped thread systems' hole and a nut is screwedon the other end of explained in chapter 9. The designof each of the the stud. A stud may be types usually permits a wide a continuous threaded range of general design with threads beginningat one end and applications for any given fastener.However, running the entire length of the some equipmentrequires stud. Another specializationof type of stud has threads beginningat each end fasteners to such a degreethat only a single and an unthreaded diameter applicationcanbemade.The in the center Of the material stud. The unthreaded diametermay be the same specificationforacertain application ofa size as the major diameter of fastener is based on the function the threads, or it of the mating may berecessedtoprovide parts, stresses, and temperaturesapplied to the clearance. A fasteners and on the elements continuous threaded stud generallyhas a class to which the 2A or 3A fit to allow relativeease in assembly. equipment is exposed, suchas steam, saltwater A stud with the center and oil. Table 3-3 isa general guide for material part unthreaded may have a different class of fiton each end. One end usage and the (::ff.,tnt identifyingmarkings found on fastenei... will have a class 2Aor 4A fit. This is the end on which the nut is screwed. Theend of the stud that screws into the tapped hole BOLTS.A bolt isdel externally threaded will have an fastener, with a threaded diameter of interference fit that will requirea torque wrench 1 /4 inch, to install it. The interferencefit is a class 5 fit 3-40 Table 3.3.-Spacificitioniond Useof hone

MARKING ON INTENDED USE GRADE CONDITION MATERIAL MATERIAL SPECS. FASTENER

GENERAL USE 5 HEAT 3 EQUALLY CARBON STEEL SAE 10XX SERIES SPACED RADIAL STEEL WITH A MAX. TREATED LINES IMUM OF 0.55%

GENERAL USE 8 HEAT 6 EQUALLY CARBON STEEL CARBON TREATED SPACED RADIAL

ti LINES

FOR USE UP TO775°F WITH GRADE 2/i AND B7 HEAT B7 ALLOY STEEL SAE 4140 TO GRADE 4 NUTS SAE 4145 TREATED

FOR USE UP TO1000°F WITH GRADE 4 NUT B16 HEAT 816 ALLOY STEEL ASTI A 193 TREATED

FOR USE HERELOW MAGNETICAND ANNEALED 303 FED. STD, 66 303 CORROSION CORROSION RESISTANTPROPERTIES ARE RESISTANT STEEL REQUIRED

MAGNETIC AND 410 FOR USE WHERE LOW FED STD. 66 410T HEAT w CORROSION CORROSION RESISTANTPROPERTIES ARE TREATED RESISTANT STEEL REQUIRED

FOR CONNECTINGNONFERROUS MATERIALS 982 482 NAVAL BRASS QQ.B.637 IN CONTACT WITH SALTWATER

FOR CONNECTINGNON.FERROUS MATERIALS 651 651 SILICON BRONZE QQ.C591 IN CONTACT WITH SALTWATER

FERROUS AND ,f 400 FOR CONNECTING QQ.N.281 CL. A&B 400 NICKLE COPPER NON.FERROUS MATERIALS(EXCEPT

ALUMINUM) IN CONTACT WITHSALT WATER ..oweaz.orwom.....=1~Npeimo.ww..MNOM..=11.I.M.Y1.1e1.

FOR CONNECTINGFERROUS AND 500 500 NICKLE COPPER QQ.N.286 CL,A NON.FERROUS MATERIALS(EXCEPT ALUMINUM ALUMINUM) IN CONTACTWITH SALT WATER

775°F WITH GRADE 117 STUD OR 2I1 (NUTS ONLY)FOR USE UP TO 2/1 HEAT CARBON STEEL SAE 10U SERIES TREATED BOLT STEEL WITH A a MAX. OF 0.55%

CARBON FOR USE UP TO1000°F WITH GRADE B16 AND HEAT 4 (NUTS ONLY) SAE 4140 to 4 ALLOY STEEL B7 STUD OR BOLT TREATED SAE 4145 .1011f..11MMO4MWINI MINOWNOPI

1 V MACHINERYREPAIRMAN 3 & 2

andisdividedinto severalsubdivisionsto thread nut that has depressions in the faceor provide the correct fit for differentmaterials threads of the nut. and lengths of engagement. A stud of thistype is screwed into the tapped hole the maximum MACHINE SCREWS', ANDCAP- distance possible without either jamming the SCREWS.Machine screws andcapscrews are end of the stud against the bottom of thehole similar except for sizerange. Machine screws or the shoulder of the unthreaded part of the have diameters up to 3/4 inch ( including size stud apAkinst the top of the tapped hole. A small numbers from 0 to 12), whilecapscrews come in amount of lubricant approved foruse in the sizes above 1/4-inch diameter. Both machine temperatUre range in which the equipment is screws and capscrews are available in several exposed 'should be applied to the threads.You head shapes, such as flat, fillister, and hexagonal. will ridthe correct tolerances and torque These screwheads are slottedso that they can oe require'd for each application incharts in most tightened with a screwdriver. handbooks for machinists. SETSCREWS.Setscrews areavailablein NUTS.A nutis an internally threaded several different styles of heads includingsquare, fastener with the same sizethreads asthe hexagon, slotted and the most external part to wItch it will be attached. common type, They the recessed hexagon socket. The pointson come in other a square or a hexagon shape and sctscrewsdiffer from the points have standard widths and thicknesses based on other on threadedfastenerstopermitapositive thebasicthr:.adsize. Any applicationof engagement witha preparedrecessinthe threaded fasteners that are subjected to working external surface on one of the matingparts it is conditions, which could cause the nut to loosen being used on. Pointsare available in either a through heat or vibration, usually hassome cone (90° point), a cup (recessed point), an oval, method of locking the mating parts securely. a flat or half-dog (a short, reduced diameter). Severalmethods areavailabletoyou:use The correct selection dependson whether the different styles of lock washers, deform thearea setscrew is intended to prevent slippage when around the threads by stakingor peening with a holding a pulley or gear ona shaft or holding center punch, install setscrews, oruse locknuts. nonrotating parts in place. There isa definite relationship between the holding Locknuts in common use power and the are of two types. diameter of a setscrew and between thenumber One type applies pressure to the boltor stud of setscrews required to transmit thread without permanent damage rotational to the thread movement of equipment rotating atany given and is used when the nut must beremoved rovolutions per minute and horsepower. If frequently. Included it -his type the are jam nuts, a equipment specifications do not specifythis thin nut that goes ui.Jer the regular nut;plastic information,it may be obtained from most angular ring and nylon plug insert nuts thatuse handbooksformachinists. the resiliency of the plastic and nylon Setscrewsare to create normally made of hardened steel,although large frictional pressures on the boltor stud; nonferrous(stainlesssteel, spring nuts that use springs of different nickel-copper, types to bronze) setscrews are available foruse when apply pressure between the nut and the working saltwater or corrosive liquids are involved. surface; and spring beam nuts that havea slight taper in the upper portion of the nut with slots Screw Thread Inserts cut to form segments which permit expansion when the nut is screwed ontoa bolt or stud. The A screw thread insert (figure 3-39) is other type of locknut deforms the threads a on helically wound coil of wire designedto screw the bolt or stud and should be used only when into an internally threaded hole andreceive a removal is seldom required. Thistype includes standard sized externally threaded (1) a distorted collar nut that has fastener. A an oval shaped screw thread insert can be used to repaira opening at the top and appliespressure when threadedhole when the threads have been forced over the bolt or stud and (2) a distorted corroded or stripped away and to providean

3-42 Chatter 3- LAYOUT AND BENCHWORK

class 2B or 3B fit will have been made. The "H" limit numbers that refer to the pitch diameter tolerance, as previously explained in the sectibn on hand taps, are marked on the taps. As an example of the amount of oversize involved, a tap required for a 1/2 - 13 UNC insert has a maximum majordiameterof 0.604inch. Because of the increase in the size of the hole required, it is important to ensure that there is sufficient material around the hole on the part to provide strength. A rule of thumb is that the minimum amount of material around the hole should equal the thread size of the insert, measured from the center of the hole. Using this rule, a1/2 -13 UNC insert will require a 1/2-inch distance from the center of the hole to the nearest edge of the part. The tap drill size 28.326 for each of the taps is marked on the shank of Figure 3-39.Screw thread insert. -the tap. The diameter of this drill will sometimes vary according to the material being tapped. increased level of thread strength when the base The next tool that you \%filluse is an metal of the part is aluminum, zinc, or other insertingtool(fig.3-40). There are several soft materials. Before using screw thread inserts differentstylesof insertingtools thatare for a repair job, carefully evaluate the feasibility designed to be used for a specific range of insert of using this method. When you have no specific sizes and within each of these styles are tools for guidance, ask your supervisor for advice. each individual size of insert. All of the inserting tools havesimilaroperatingcharacteristics. Screw thread inserts come in sizes up to Either slip the insert over or screw it onto the 1 I /2-inch diameter in both American National shank of the tool until the tang (the horizontal and Unified, coarse and fine thread series. The strip of metal shown at the top of the insert in overalllength of aninsertis basedbn a figure '3-39). solidly engages the shoulder or fractional multiple of its major dignipter. A recess on the end of the tool. Then install the 1/2-inch screw threadinsertisavailable in lengths of 1/2,. 3/4, 1 inch, etc. rScrew thread inserts are normally made from , however a phosphor bronze and a nickel alloy insert are available by special order. A stainless C11111111k01111111) steelinsertshould NOT beusedinany applicationwhere thetemperatureexceeds 775°F or where a' corrosive material such as acid or saltwater is involved.

There are several tools associated with the installation and removal of screw thread inserts that areessential if the job is to be done correctly. The most important tool is the tap U used to thread the hole that the insert will be INSETTING TOOL EXTRACTOR screwedinto.These tapsareoversized by specific amounts according to the size of the 28.327 insert, so that after installation of the insert,.a Figure 3-40.Screw thread insert tools.

3-43 MACHINERY REPAIRMAN 3 & 2

insert by turning the tool until thecorrect depth at the tap of the hole. Remove allchips from the is reached. Remove the tool byreversing the hole. direction of rotation. After the insert has been properly 4. Tap thehole. Use standard tapping installed, procedures in this step. Lubricants you must break off the tang to preventany should be interference with the fastener thatis to be used to improve the quality ofthe threads. screwed into the hole. A tang break-off When completed, inspect the threadsto ensure tool is that full threads have been cutto the required available for all insert sizes of 1/2inch and depth of the hole. Remove all chips. below. The tang has a slight notch groundinto it 5. that will give way and break when Next, install the insert. If the holebeing struck with repaired is corroded badly, apply the force of the punch-type,tang break-off tool. a small amount On insert sizes over 1/2 inch of preservative, suchas zinc chromate, to the use a long-nosed tapped threads immediately prior pair of tomove the tang back and forth to installing until it breaks off. the insert. Position the inserton the insert tool When it is necessary toremove a previously as required by the particular style beingused. installed screw thread insert,use an extracting Turn the tool clockwise to installthe insert. tool (fig. 3-40). Thereare several different sized Continue to turn the tool until theinsert is tools that cover a given approximately 1/2 turn below thesurface of the range of insert sizes; be part. sure you select the correct sized tool. Insertthe Removethetoolbyturningit tool into the holeso that the blade contacts the counterclockwise. 6. top coil of the insert approximately 90°from Use an approved antiseize-,compound the beginning of the insert coil.Then, lightly hit when screwing the threaded boltor stud into the the tool to cause the bladeto cut into the coil. insert. The use of similar metalssuch as a Turn the tool counterclockwiseuntil the insert stainless insert and.a stainless bolt should be is clear. avoided to prevent gallingand seizing of the threads. The steps involved inrepairing a damaged threaded hole witha screw thread insert is as follows: Keyseats and Keys

1.Determine the original threadedhole Keyseats are size.Select the correct standard sized grooves cut along the axis of screw either the cylindrical surface ofa shaft or the thread insert with the length thatbest fits the bored hole in a hub. Metal application. Be sure the metal from keys of various which the shapes are fitted into thesegrooves to provide a insert is made is recommended forthe particular positive means for transmitting application. toque between a shaft and a hub. There are basically three 2.Select the correct tap for the insert types., to be of keys: taper, paralleland Woodruff. The installed. Some taps come in sets ofa roughing and a finishing tap. You saculd standard taper keys havea taper of 1/8 inch per ensure that both foot and are eithera plain taper or a gib head taps are used prior to an attemptto install the insert. taper style key. Taper keysare not often found 3. on marine equipment and willnot be covered Select the correct sized drill basedon the in thistext. Parallel ,keys consist mainly information on the shank of thetap or from of charts normally supplied with square and rectangular shaped keys.These are the insert kits. probably the mostcommon types of keys that Measure the part with a rule to determineif the you will work with. A Wcodruff preveiously referenced minimum key is a distance from semicircular shaped key designed the hole to the edge of thepart exists. With all primarily to involved tc ols and parts secured permit easy removal of pulleys fromshafts. Keys rigidly in place, are made from several different types of drill the hole to a minimumdepth that will metal permitfull including medium carbonsteel, nickel steel, threads to be tappeda distance nickel-copper alloy, stainless equaling or exceeding the lengthof the insert, steel and several not counting any spot-faced bronze alloys. Each differentkey style and or countersunk area material hasa particular use for which it is best

3-44 Chapter 3LAYOUT AND BENCHWORK suited, depending on the forces and elements different classes. Each of the classes gives the subjected to the equipment. Consult blueprints recommended tolerance on both the key and the or other technical references when replacing a keyseat for the fit on the sides and the top and key to prevent selecting one that willnot bottom of the keyed assembly. The top and perform as required. bottom tolerances for the key and keyseat Square keys (fig. 3-41A) are recommended assemblies generally provide a range of fits from for applications where the shaft diameter is 6 ametaltometaluptoapproximately__ 1/2 inches and below, while rectangular keys 0.040-inch clearance (depending on the width of (fig.3-41B)arerecommendedforshaft the key) for all three classes of fits. The side fit diameters over 6 1/2 lhes. Some applications for a class 1 fit allows for a metal to metal may require that two keys be installed to drive 0.017-inchclearancefit.The amountof equipment having a high torque value. The clearance increases as the width of the key width and the height of a key are dependent on increases. A class 2 fit allows for a side fit the diameter of the shaft that it will be used on, rangingfroma0.002-inchclearance to an while the length of the key is based on the key's interference fit of up to 0.003 inch. A class 3 fit width. A chart giving some of the more common allows only an interference fit for the sides of sizesof shafts and recommended key size the key with individual applications determining combinations is provided in table 3-4. the amount of interference involved. Complete charts showing the recommended key sizes for Parallel keys (square and rectangular) and differentshaftdiameters and the allowable thekeyseats machinedto accept them are tolerance for each of the classes of fits are designedtoprovide assemblyfits' of three available in most handbooks for machinists.

L C 1-W " L-III 1-w _r0 -7-11 FLAT BOTTOM OPTIONAL

A SQUARE B RECTANGULAR C. WOODRUFF

28.34 Figure 3.41. Types of keys and keyseats. 3-45 j MACHINERY REPAIRMAN 3 &2

Table 3-4.Key Size Versus Shaft Diameter

SHAFT DIAMETER KEY SIZE KEY LENGTH "L"

WIDTH "W" HEIGHT "H" MIN. MAX. 1 FROM- TO SQUARE RECTANGULAR4 X W 16 X* 7/8" 1 1/4" 1/4' 1/4" 3/16" 1" 1 1/4" 1 3/8" 4" 5/16" . 5/16" 1/4" 1 1/4" 5"-- 13/8" 1 3/4" 3/8" 3/8" 1/4" 11/2" 6" 13/4" 2 1/4" 1/2" 1/2" 3/8" 2" 8" 4 1/2" 5 1/2" 1 1/4" 1 1/4" 7/8" 5" 6 1/2" 7 1/2" 20" 1 3/4" 1 3/4" 1 1/2'1 7" 28"

Selectiveexcertsextractedfrom "American Society ofMechanical Engineers" USAS B17.1-1967 Page 2, table 1

The ends of square or rectangular keys are Positive fitting of the key in the often prepared witha radius equal to one-half keyseat is provided by making the key 0.0005to 0.001 the width as shown in thetop illustration of inch wider than the seat. figure3-41B.This designpermitsasnug assembly fit when the machiningon the keyseat Information on the machining of was done with a conventional milling machine keyseats for parallel and Woodruff keysis included in and an cutter. chapter 11.

Woodruff keys(fig.3-41C)are Pins manufacturedinvariousdiametersand thicknesses. The circular side of the key is seated The threepins commonly used inthe in a keyseat milled in theshaft with a cutter machine shop are the dowel pin, the having the same radius and taper pin, thickness :Is the key. and the cotter pin. The DOWELPIN, which is made of machine-finished roundstock, is used The size of a Woodruff keyis designated by a system of numbers which for aligning parts. It is used insuch applications represent the as pump housings. A hole in thehousing nominal key dimensions. Thelast two digits of matches with a hole in the end the number indicate the diameter casing and a of the key in dowel pin is inserted to provideexact alignment. eighths of an inch, while the digit or digits As this is an aligning pin the dowelmust have a preceding them indicate the widthof the key light drive fit. The TAPER in thirty-seconds ofan inch. Thus, a number 404 PIN which has a 1/4-inchperfoottaperisusedtohold key would be 4/8 or 1/2 inchin diameter and slow-speed, low-torque, rotor-shaft 4/32or 1/8 inch wide, while a number 1012 key applications, such as hand-operated wheelsand levers on would be 12/8 or 1 1/2 inchesin diameter and machine tools. When taper pins 10/32 or 5/16 inch wide. are used, the hole must be drilled and thenreamed with a To make taper pin reamer to obtain thecorrect fit. properassemblyof keyed COTTER PINSare members, clearance is required doubledsectionsof oetween the top half-round metal stock whichare used primarily surface of the key and the keyseat. This to lock nuts in place clearance is normally approximately on bolts. All pins come in a 0.006 inch. variety of standared sizes andlengths. Most

3-46 Chapter 3LAYOUT AND BENCHWORK machinist's handbooks give information on hole and normal operating temperatures of 150° to sizes and numbers for specific dimensions of 1000°F are within the range that these gaskets pins. can effectively seal a system. Each application requiresaspecificgasket andiubstitutions Gaskets, Packing and Seals should not be considered. When installing this gasket,tightenthefastenersevenlyon Many of the repair jobs that you do will diagonally opposite bolts until the gasket is require installation of gaskets, packing, or seals compresseu to the thickness required for the to prevent leakage. Gaskets are used mainly for particular application. sealing fired type joints such as flanged pipe and Synthetic rubber and .-..,th inserted rubber valve joints and pump casings, while packing and gaskets are used on fresh..;-- and seawater seals are used for sealing joints where one part systems with pressures of 5L... psi and moves in relation to the other. All of these temperatures of 150° to 250°F. sealing devices are available in a wide range of diameters,thicknessesandclassifications Gain line and JP-5 systems a gasket (grades)toprovidesuitablesealing of any m:., iniT1 Buna-N and cork. Th,sf the system or equipment. A general knowledge of wro...-4; gasket material in the thedifferent -sealing materialsisimportant result r. deterioration of 'ix however, theproper selectionof a gasket, catitainn.....'on of the system aLai,doty: packing or other seal nust never be based on situatiol.:-;.,; -7. a leak develops. general application guidelines or memory. The Prior to ing any gasket, carefully in. modern ships of today have systems that reach spect ohe mating parts for curs c' 1000°F in temperature and 2050 psi in pressure scratches !.7.ai will p vent the proper sealing cf under normal operating conditions. A wrong the gasket. Wholieny doubt exist, refinish the selection can cause serinus injury to personnel surface. You,soin find additional information on andmajordamagetoequipment.The flange refirdshing later in this manual,. equipment's technical manual, allowance parts list,ship'splanon theappropriate PMS Packing Maintenance Requirement Card are sources that can provide the exact specifications required nor The packing used to seal against leakage the sealing device. around equipment, such as valve stems on pump shJts, is available in many different material A brief description of some of the mot: types,sharesandsizes.Specific common types of gaskets, packing, and sears recommendations on packing selection is best used in shipboard equipment and their gene -:al I.';`.to the appropriate technical document; applicationisprovidedinthefollowing however, there are some common errors made in paragraphs. packingselectionandbstallationthatare important to note. PackirF, uhat has a metallic or Gaskets semimetallic base should not be used on a brass or bronze part. Parts that are softer than 250 Spiral wound, metallic-asbestcs gaskets are BRINELL, hardness should not be packed with a composed of alternatelayersof dovetailed copper bearing packing. The surface condition stainless steel ribbon and strips of asbestos of the valtk, stem or ,haft and he stuff re box spirally wound, ply upon ply, to the desired into which the packing is placed are .rtant diameter. The gasket is then placed in a solid also. A surface that has pitts and scratches ,vhicl. steel retainer ring to keep the gasket material could provide a path for leakage should be intact, to assist in centering the gasket on the repaired. An out-of-round condition will cause flanges and to act as a reinforcement to prevent excessive clearance between the packing and the blowouts. This type gasket is used nn steam, rotating part. A relatively .iiew type of packing boilerfeedwater,fuelandlubricatingoil calledcorrugated ribbonpacking, which is systems. System pressures of 100 to 2050 psi ,ntended for steam valves, requires very c;,--ise

3-47 L.; % MACHINERY REPAIRMAN 3 &2

control the finishes,dimensions, and equipment manufacturer should be concentricity of the parts thatcontact it. Each followed part r -lit be measured and checked very closely to ensure the correct loading and carefully proper functioning of the seal. Shaft before this type packingcan be used. runout, alignment, andid play (thrust) must be within Seals the limitations prescribed for theequipment. 0-rings may be used asa static seal where no The types of seals motion exists between themating parts or as_a_ you will work with most d y namicsealwherea often are oil seals, mechanicalseals and 0-rings. reciprocating,an 'Each type requires careful oscillating, or a rotary motion existbetween the attention to the mating parts. 0-ringsare made from either contact area and the installationprocedures to synthetic or natural materials ensure a good seal against leakage. which have the capability of returning to theiroriginal shape and size after being deformed. Oil seals are probably thesimplest of the The substance being 4aled and the operating.pressures and three types of seals to install.They consist of a metal cup or flange retainer, temperatures are very importantfactorsin which press fits cl,:termining the exact 0-ringto use in any given into a cylindrical bore, anda spring-loaded rubber or neoprene lip, which applic..tion. Preparation of the0-ring groove make contact requires special care toensure that the specified with the shaft. The spring willcause the seal to finishanddimensionsareobtained.The maintain a firm contact 'km shaft even if annular or circular finish there is a small amount of shaft pattern (lay) produced runout. The seal by a lathe prwidesa surface tiat allows a more contact area on the shaft must befree of pitts, scratches and old effective seal than one producedby an end mill wear patterns to operate as cutter in a milling machine. A designed. When replacing roughness valve of a seal of this type, be 32 mic-oinchesfora particularly careful in selecting the staticsealand15 proper seal as microianhes for, dynamic sealis generally indicated by the equipmentmanufacturer. The acceptable for tht 0-ring type of fluid being sealedand the operating groove. To achieve temperature are as important in maximum effectiveness,an 0-ring should not be correct seal stretched more'.an 5% beyond the designed selection as the dimensions ofthe seal. dimerisiiof theL Mechanicalsealsare idL diameter after the 0-ring considerably more isinpositionin the groove. Thiscan be difficult to install correctly. Themajority of me- controlled only by accurate chanical seals consist ofone part that is sealed machining and against the housing or seal retainer measuring of the depth of the0-ring grc,ove. with a gasket Excessive widttof the groove will al:c or 0-ring, while another part of theseal is w the attached to the shaft and is 0-ring to roll or twist duringinstallation and sealed by a ribber or operation. 7 any a: ph;ations neoprene bellows. Each of these two require the use of parts has a backup rings whichare placed one cne. or both flat-facedseal that makesa rubbing contact sides when the shaft is turning. One of the0-ringtoprovideadditional of the flat -faced protectionagainst0-r1lg seals is spring-loaded tomaintain a constant distortion under contact pressure when end play pressure. The .:quipnient specificationsshould occurs in the be reviewed caret' .11;to determine if a bacle.-ip equipment operat on The flat-facedseals may ring is required. An approved be made from carbon, alloysteel, ceramic, or 0-ring lubricari. is severalother essential during installationto prevent damage materials.Regardlessof the to the 0-ring andto enhance the sealing material used for these parts,they should be handled very carefully effectiveness. The lubricant se'ectedshould be to avoid damage. The one that will not affect the 0-ring installation instructions provided material or by the seal or contaminate thesub..ance being seile

3-48 CHAPTER 4

METALS AND PLASTICS

A Machinery Repairmanisexpected lo squeezes the metal. stress is forces from repairbrokenpartsandtomanufacture opposite directions that work to separate the replacements in accordance with samples and metal. When a piece of metal is bent, both blueprints. To choose the metals and plastics tensile and compression stress are applied. The best suited for fabrication of replacement parts, side of the metal where the force is applied you must have a knowledge of the physical and undergoes compression stress as the metal is mechanical properties of materials and know the squeezed, while the opposite side is stretched methods of identifying materials that are not under tensile stress. When a metal is subjected to clearly marked. For instance, stainless steel and a tot.onal load such as a sump shaft driven by nickel-copper are quite similar in appearance, an electric motor, all three forms of stress are but completely different in their mechanical applied to a certain degree. properties and cannot be used :nte-changeably. A themosettingplasticmay h.%likea STRAIN thermoplastic but the former is heat resistant, whereas the latter is highly flammable. Some of Strain is the djormation or change in shape the properties of materials that an MR3 and of a metal that results when a stress or load is MR2 must know are considered in this chapter. applied. When the load is removed, the metal is no longerunderastrain.Thetypeof deformations which result when a metalis PkOPERTIES OF METALS subjected to a stress will be similar to the ft. a of stress applied. The physical properties of a metal determine its behavior under stress, heat, and exposure to STRENGTH chemicallyactivesubstances.Inpractical application, behavior of a metal under these Strength is the property of a metal which conditions determines its mechanical properties; enables it to resist strain (deformation) when a indentationandrusting.Themechanical stress (load) is applied. The strength of a metal properties of a metal, therefore, are important may be expressed in several different terms; the considerations in selecting material for a specific most cc mmonly used term is tensile strength. job. Tensile strength is the maximum force required to pull metal apart. To find the tensile strength STRESS of a mf:tal, divide the force required to pull the metal apart by the area 'n square inches :of a Stress in a metal is its internal resistance to a prepared specimen. change in shape (deformation) when an external load or force is applied to it. There are three The maximum force required to cause a different forms of stress to which a metal may metal to part is called its ultimate striffith. To be subjected. Tensile stress is a force that pulls a minimize the possibility of a part failing due to metal apart. Compression stress is a force that excessive working stresses, a, factor of safety is MACHINERY REPAIRMAN 3 & 2

designed into the part. A factor ofsafety means findthedftztility of a metal, that the ultimate strength of the metal measure the is two or percentage of elongation which L.1sultswhen the more times greater than the working stressesto metal :s stretcfed during the `ensile which the part will be subjected. strength test. opper is an example ofa very ductile met Another term used often to describethe strength of a metal is yield strength.The yield MALLEABILITY strength is determined thiring_thesame test that establishesthetensilestrength.Theyield Malleability is the ability of strength is established when the a metal to be metal specimen permanently deformed bya compression stress first begins to elongate (stretch) whilepressure is produced by hammering, stamping, gradually applied. A relationship ol. rolling between the the metal into thin sheets. Leadis a highly tensile strength of metals and theirhardness is malleable metal. often present. As the hardness ofa metal is increased, the tensile strength is alsoincreased BRITTLENESS and vice versa. Chartsare available that provide thesevalues for the more commonlyused Brittleness is the tendency of metals. a metal to break or crack withno prior deformation. Generally, the harder Some other terms that a metal, the more brittle it may be used to is, and vice versa. Pot metal andcast iron are describeametal's strength are compression examples of brittle metals. strength, shear strength, and torsionalstrength. You will not see these termsoften. However, in TOUGHNESS certain design applications, wherestress would result in strains of one of these types being Toughness isthe quality that enablesa applied to a part, yolt would needto establish material to withstand shock, to endure and use specific values in safety stresses computations. and to be deformed without breaking.A tough material is not easily separated PLASTICITY or cut and can be bent firstin one direction and then inthe opposite without fracturing. Plasticityistheabilityof ametalto withstandextensivepermanent deformation HARDNESS without breaking or rupturing. Modelingclay is an example of a highly plastic material,since it Hardness of a metal is generally defined can be deformed extensively and permanently as its ability to resist indentation,abrasion or wear, without rupturing. Metals witha high plasticity and cutting. The degree of hardness value will produce long, continuous of many chips when metals r. ay be zither increasedor decreased by machined to a lathe. being subjected) one or more heat treatment' ELASTICITY processes. In must cases, as the hardness ofa steel is de -Teased, the toughness isincreased. Elasticity is the ability ofa metal to return HARDEN.ABILITY to its original size and shape afteran applied force has been removed. Steel usedto make Hardenability is a springs is an example of this measure of the depth property. (from the metal's surfacetoward its center) that DUCTILITY a metal can tx. hardened by heat treatment.A metal that achievesa shallow depth of hardness Ductilityis the ability of and retains a relatively soft and toughcore has a a metal to be low hardenability value. Thehardenability of permanently deformed by berdingor by being stretched into wire form without some metals can be changed by the addition of breaking. To certain alloys during the manufacturingprocess.

4-2 Chapter 4METALS AND PLASTICS

FATIGUE The basic factor is the chemical composition or the elements that were added during the metal's Fatigue is the action which takes place ina manufacture. A steel with a low carbon content metal after a repetition of stress. When a sample will be much easier to weld than a metal with a is broken in a tensile machine, a definite load is high carbon content. A low alloy steel that has a required to cause that fracture; however, the low hardenability value will lend (itself--more-- same material will fail under a much smaller load readilytoweldingthan one withahigh if that load is applied and removed many times. hardenabilityvalue. The welding procedure, In this way, a shaft may break after months of suchas gas orarcwelding, also must be vse even though the weight of the load has not considered. The design of the part, its thickness, been changed. The pieces of such a part will not surface condition, prior heat treatments, and the show any sign of deformation; but the mating n.ethocl of fabrication of the metal also affect areas of thesection thatfractured last will the weidability. Charts are available that provide usually be quite coarse grained, while the mating guidelines concerning the weldability of a metal areas of other sections of the break will show and the recommended welding procedure. The signs of having rubbed together for quite some weldability of a metal should be considered an time. integral part of planning a job that requires the manufacture or repair of equipment components CORROSION RESISTANCE if any metal buildup or weld joint is involved.

Corrosionresistanceistheability of a MACHINABILITY materialto withstand surface attack by the atmosphere, fluids, moisture, and acids. Some Machinability is the relative ease with which metals are highly resistant to practically all types a metal can be machined. Table 4-1 lists the of corrosive agents, others to some types of relative machinability rating of most of the corrosive agents, and still others to only a very metals used in machine shops. The machinability few types of corrosive substances. Some metals, of each metal is given as a percentage of 100, however,canbemadelesssusceptibleto with B1112, a resulphurized, force-machining corrosive agents by coating or by alloying them steel, used as a basis for comparison. The higher with other metals that are corrosion resistant. rated metals can be cut using a higher cutting speed or surface feet per minute than those HEAT RESISTANCE metals with lower percentage values. There areseveralfactors that affect the Heat resistance is that property of a steel or machinability of a metal: a variation in the alloy that permits the steel or alloy to retain its amount or type of alloying element, the method propertiesatelevatedtemperatures.For used by the manufacturer to form the metal bar example; red ± hardness in tungsten steel; high (physical conditon), any heat treatment which strengthforchromium molybdenumsteel; has changed the .iardness, the type of cutting nondeforming qualities for austinitic stainless toolused (high-speedsteelor carbide) and steel; malleability for steels. Tungsten whetherornotacuttingfluidisused. steel (which even when red hot can be used to Information concerning some of these factors cut other metals) and chromium molybdenum will be discussed later in this'. chapter and in steel (which is used for piping and valves in high chapter8.Detailsof the AISI and SAE temperature, high-pressure steam systems) are designations used in the chart are explained later examples of heat resistant metals. in this chapter.

WELDABILITY METALS Weldability refers. to the relative ease with which a metal can be welded. The weldability of Metalsaredividedintotwogeneral a metal part depends on many different factors. typesferrous and nonferrous. Ferrous metals

4-3 MACHINERY REPAIRMAN 3 & 2

Table 4-1.-Machinability Rating

SAE-AISI BHNMachinability SAE-AISI BHNMachinability SAE-AISI Numbers BHN Machinability SAE-AISI BHN Numbers S Numbers Machinability X Numbers Plain Carbon Steels Nickel Steels Nickel-Moly Steels Nickel -Chrome-Moly Steels NI 5.00% NI 3.50% Mo 0.21 B -1006 147 78 Ni 3.251 C> 1.20% Mo 0.12% B-1010. 147_ 78 2512 -210 51 4812 249 51 C-1008 175 66 2515 212 E 9310 243 48 52 4815 256 51 C-1010 172 65 NE 2517 215 E 9315 238 50 51 4817 251 51 C-1015 160 72 E9317 239 49 4820 248 53 C-1016 148 78 Nickel-Chrome Steels C-1017 163 72 NI 1.25% Manganese-Nickel-Chrome-Moly Chrome Steels C-1019 146 78 Steels Cr 0.65% or 0.80% Cr 0.30% or 0.60% C-1020 162 72 Mn 1.00% Ni 0.",14- C-1022 147 78 3115 191 Cr 0.40% Mo 0.12% 66 188 70 C-1023 154 75 3120 190 66 :044: 18G C-1025 162 70 9437 182 72 3130 213 57 66 C-1030 164 70 183 3135 225 53 Chrome Steels 66 C-1035 :44,1 162 70 3140 282 44 179 66 C-1040 179 Cr 0.80%, 0.95% or 1.05% 64 3145 192 64 181 64 C-1043 178 64 3150 201 60 5120 187 75 C-1045 199 60 ::::el-Chrome-MolySteels 5130 241 C-1046 203 57 57 Ni 0.55% Cr 0.17% Mo 0.20% Nickel-Chrome Steels 5132 189 72 C-1050 210 55 NI 3.50% Cr 1.55% 5135 188 72 C-1054 217 53 9747 187 64 5140 192 70 C-1055 221 52 E 3310 9763 215 54 241 51 5145 210 65 C-1059 222 52 E 3316 250 55 5147 211 66 C-1060 223 51 Nickel-Chrome-Moly Steels 5150 215 64 C-1064 224 50 Hi 1.00% Cr 0.80% Mo 0.25% Molybdenum Steels 5152 216 64 C-1065 229 50 Mo 0.25% C-1069 231 48 9840 232 50 C-1070 230 49 Carbon-Chrome Steels 9845 238 43,7 185 78 C 1.00% 49 C-1075 238 48 9850 242 45 4023 182 78 Cr 0.50., 1.00% or 1.45% C-1080 271 42 4024 182 78 C-1085 269 42 4027 Steels 212 66 E 50100 211 45 C-1090 273 42 4028 191 72 E 51100 C-1095 274 221 40 302 42 4032 184 76 45 E 52100 220 40 303* 4037 189 73 60 304 Resulphurized Carbon Steels 198 70 45 Bessemer FCC Chrome-Vanadium Steels 308+ :0,4 204 65 27 Cr 0.85% or 0.95% 309+ 4053 261 53 V 0.10% or 0.15% 28 C-1106 150 314+ 79 4063 153 52 32 C-1108 149 80 317+ 29 C-1109 202 57 321 152 81 Chrome-Moly Steels 36 :a25 182 66 C-1110 148 83 330* 27 Cr 0.95% Mo 0.20% 6150 192 8 -1111 131 94 60 347 6152 36 8-1112 122 100 195 60 403 4130 181 72 39 8-1113 101 132 410 E 4132 190 72 54 C-1113 120 Nicker Chrome -holy Steels 416* 100 4135 189 70 72 C-1115 150 81 Ni 0.55.: Cr 0.50% Mo 0.23% 420 4137 209 65 57 C-1116 139 94 420 79 E 4137 205 67 8617 182 C-1118 139 66 91 4140 212 62 54 C-1119 8620 183 66 ::* 120 100 4142 227 91 59 8622 185 65 440 C-1125 152 81 4145 221 37 , 60 8625 189 62 440 A C-1126 150 81 4147 219 45 60 8627 188 64 440 B C-1137 169 72 4150 242 59 42 8630 161 72 C-1138 164 75 40 8635 165 70 C-1140 171 72 59 Nickel- Chrome -Holy Steels 8637 164 C-1146 167 76 70 NI 1.80% Cr 0.50% Mo 0.25% 864G 172 66 C-1151 180 70 ;rrTstMachining Properties. 8642 177 65 Y Good Machining-Contain 4317 21; 60 8645 182 Manganese Steels 64 Sulfqr aad Selenium. 4320 20i 63 8647 Mn 1.75% 194 60 * Best Machining Properties. E 4337 243 54 8650 195 A0 4340 240 57 8653 1320 210 57 203 56 Cast Iron E 4340 239 57 . 8655 205 1321 212 59 57 8660 215 54 Soft NE 1330 210 60 Nickel-Moly St-els 130 81 1335 211 60 NI 1.80% Mo 0.5% Medium 168 64 NE 1340 216 57 Nickel-Chrome-Holy Steels Hard 243 47 NI 0.55% Cr 0.50'4 Mo 0.259% 4 8 242 58 Nickel Steels E460617 201 66 Malleable Iron NI 3.50% 8719 175 67 4615 192 66 8720 178 66 4620 Malleable 198 64 171 70 2317 185 66 X 4620 Iron 115 106 193 66 FAO 183 66 2330 220 55 E 4620 Malleable 202 64 8742 185 64 2335 242 51 4621 Iron 135 199 66 8747 192 60 2340 210 57 4640 198 66 8750 194 2345 231 51 60 E 4640 245 51 Cast Steel Manganese-Filicon Steels Cast Steel Mn 0 55% SI 2.00% 121 85 Cast Steel219 50 Cast Steel245 44 9255 122 54 9260 238 51 9262 235 49

rl 4-4 Si Chapter 4METALSAND PLASTICS are those whose major element is iron. iron is Wrought Iron the basis for all steels. Nonferrous metals are those whose major element, aot iron, but they Wrought iron is a highly refined pure iron may contain a small amount of iron as a.1 which has uniformly distributed particles of slag impurity. in its composition. Wrought iron is considerably softer than cast iron and has a fibrous internal FERROUS METALS structure, created by the rolling and squeezing given to it when it is being made. Like cast iron, wrought iron is fairly resistant to corrosion and Iron ore, the basis of all ferrous metals, is fatigue.Wroughtiron,becauseofthese converted to metal (pie iron) in a blast furnace. characteristics, isusedextensivelyfor Alloying elements can be added later to the pig low-pressure pipe, , and nails. iron to obtain a wide variety of metals with different characteristics. The characteristics of Plain Carbon Steels :netal can be further changed and improved by heat treatment and by hot or cold working. Pig iron is converted into steel by a process which separates and removes impurities from the Pig Iron molten iron by use of various catalytic agents and extremely high temperatures. During the The proodct of the blast furnace is called pig refining process, practically all of the carbon iron. In early smelting practice, the arrangement originally present in the pig iron is burned out. of the sand molds into which the molten crude In the final stages when higher carbon alloys are iron was drawn resembled groups of nursing desired, measured amounts of carbon are added pigs, hence the name. to the relatively pure liquid iron to produce Pigironwhichiscomposedof carbon steel of a desired grade. The amount_of approximately 93% iron, 3% to 5% carbon, and carbon added controls the mechanical propertids varying amounts of impurities, is seldom used of the finished steel to a large extent, as will be directly as an industrial manufacturing material. pointed out in succeeding paragraphs. After the Itis, however, used as the basic ingredient in steel has been drawn from the furnace and making cast iron, wrought iron, and steel. allowed to solidify, it may be sent either to the stockpile or to shaping mills for rolling and forming into plates, billets, bars or structural Cast Iron shapes. Plain steels. that have small additions of Cast iron is produced by resmelting a charge sulfur (and sometimes phosphorous) are called of pig iron and scrap iron in a furnace and freecuttingsteels.These steels have good removing some of the impurities from the machiningcharacteristicsandareusedin molten metal by using various fluxing agents. applications similar to carbon steels. Addition of There are many grades of cast iron as to strength sulfur and phosphorous results in limiting its and hardness. The quality depends upon the ability to be formed hot. extent of refining, the amount of scrap iron used, and the method of casting and cooling the LOW CARBON STEEL (0.05% to 030%), molten metal when it is drawn from the furnace. usually referred to as mild steel, can be easily The higher the proportion of scrap iron, the cut and bent and does not have great tensile lower the grade of cast iron. Cast iron has some strength, as compared with other steels. Low degreeofcorrosionresistanceandgreat carbon steels which have less than 0.15% carbon compressive strength, but at best the metal is are usually more difficult to machine than steel brittleand has a comparatively low tensile with a higher carbon content. strength and, accordingly, has very limited use in MEDIUM CARBON STEEL (0.30%to marine service. 0.60% carbon) is considerably stronger than low

4-5 MACHINERY REPAIRMAN 3 &2

carbon steel. Heat treated machineryparts are resistance made of this steel. arerequired. Greater amounts of vanadium are added to high-speedsteel cutting HIGH CARBON STEEL (0.60to 1.50%) is toolsto used for many machine parts, preventtemperingwhenhigh handtools, and temperaturesaregenerated by the cutting cutting tools, and is usually referredto as carbon action. tool steel. Cutting tools ofhigh carbon steel shouldnot beusedwhenthecutting NICKEL.Nickel temperature will exceed 400°F. isaddedtosteelto increasecorrosionresLtance,strength, Alloy Steels toughness, and wear resistance. Nickelis used in small amounts in the steel forarmor plating of a ship due to its resistanceto cracking when The steels discussed thus farare true alloys of iron and carbon. When other penetrated. Greater amounts of nickelare added elements are tochromiumtoproduceametalwhich added to iron during the refiningprocess, the withstands resulting metal is called alloy severeworkingconditions. steel. Mere are Crankshafts,rearaxles, many types, classes, and grades of alloy andotherparts steel. subjected to repeated shockare made from Alloy steels usually contain severaldifferent nickel chrome steel. alloying elements with eachone contributing a different characteristic to themetal. Alloying MOLYBDENUM.Molybdenum is addedto elementsc an changethemachir ability, steel to increase toughness, hardenability, weldability, corrosion hardenability, shock resistance resistance and resistance to softeningat high andthesurfaceappearance of themetal. Knowledge of how each of the temperatures. Molybdenum steelis used for alloying elements transmissiongears,heavy duty affect a metal will allowyou to more readily shafts,and select the best metal for springs. Carbon molybdenum (CMo)and chrome a given application and molybdenum (CrMo) are two alloy then to determine which, ifany, heat treatment steels with molybdenum added thatare widely used in high process should be applied to achievethe best temperature mechanical pipingsystemsin Navy ships. properties. A few of themore Relatively. large amounts of common alloy steels and the effects of molybdenum are certain used to form some of the cuttingtools used in alloyingelementsuponthemechanical the machine shop. properties of steelare discussed briefly in the following paragraphs. TUNGSTEN.Tungsten is used primarilyin high-speed steel or cemented carbide CHROMIUM.Chromium is added cutting to to steel tools. It is this alloy that givesthe cutting tools increasethehardenability,corrosion their hard, wear resistant and resistance, toughness, andwear resistance The heat resistant most common characteristics.Tungsten hasthe additional usesof chromiumarein property of being air- and corrosionresistantsteel allows tools (commonlycalled to be hardened without using oilor water to stainless steel) and high-speedcutting tools. cool the tool after heating. Stainless steel is often used to manufactureparts which will be subjected toacids and saltwater and for such parts as ball bearings, shafts and NONFERROUS METALS valvestemsinapplicationsinvolving high-pressure and high temperature. Copper, nickel, lead, zinc, tin,and aluminum VANADIUM. Vanadium is addedin small are included among the nonferrous quantit3s to steel to increasetensile strength, metals. You willfindthat these metals, and themany toughness, and wear resistance. Itis most often combinations in the form of alloys combined with chromium in such as brass, a steel and is used bronze, copper-nickel, andso on, are used in for crankshafts, axles, pistonrods, springs, and largeamountsintheconstructionand other parts where high strengthand fatigue maintenance of Navy ships.

4-6 3 Chapter 4METALS AND PLASTICS

Copper Alloys bronzeis used for bearings, bushings,pump bodies, valves, impellers, and gears.

Copper is a metal which lends itself toa ALUMINUM BRONZE.Aluminum bronze variety of uses. You willsee it lboard ship in the is actually a copper-aluminum alloy that- does form of wire, rod, bar, sheet, plate, and pipe. As not contain any tin. It is made of 86%copper, a conductor of both heat and electricity, it ranks 8 1/2%-99% aluminum (Al), 2 1/2%-4% iron and next to silver; it also offers a high resistance to 1% of miscellaneous alloys. It is used for, valve saltwater corrosion. seats and stems, bearings, gears, ppellers, and Copper becomes hard when worked butcan marine hardware. be softened easily by heating toa cherry red and then cooling. Its strength, however, decreases COPPER-NICKEL.Copper-nickel alloyis rapidly with temperatures above 400°F. used extensively aboard ship because of its high Pure copper is normally used in moldedor resistance to the corrosive effect of saltwater. It shaped forms when machinik is not required. is used in piping and tubing. In sheet form it is Copper for normal shipboarduse generally is used to construct small storage tanks and hot alloyed with an element that provides good. waterreservoirs.Copper-nickelalloymay machinability characteristics. contain either 70% copper and 30% nickelor 90% copper and 10% nickel. It has the general BRASS.Brass is an alloy ofcopper and working characteristics of copper butmust be zinc. Complex brassesarethose containing worked cold. additional alloying agents, suchas aluminum, These and the many other copper alloys lead,iron, manganese, or phosphorus. Naval commonly used by the Navy have certain brassis a true brass containing about 60% physical and mechanical properties (imparted by copper, 39% zinc,and1% tin addedfor the various alloying elements) whichcause each corrosion resistance.Itis used tor propeller different alloy to, be more efficient fora given shafts, valve stems, and marine hardware. applicationthan another wouldbe.Itis Brass used by the Navy is classifiedas leaded irnportanto remember this when yougo to the or unleaded, meaning that small amounts of lead metal storage rack and select a bronze-looking may or may not be used in the copper-zinc metal without regard to the specific type. The mixture. The auuition of lead improves the part you make may fail prematurely in spite of machinability of brass. the skill and attention to detail thatyou use to machine it. BRONZE.Bronze is primarilyan alloy of copper and tin, although several other alloying elements are added to produce special bronze Nickel Alloys alloys. Aluminum, nickel, phosphorous, silicon and manganese are the most widely used alloys. Nickelisa hard, malleable, and ductile Some of the more common alloys,their .netal. It is resistant to corrosion and therefore chemical analysis and some g are often is used as a coating on other metals. listed in the following paragx hs to give yo an Combined with other metals inan alloy,it idea of how basic bronze is changed. makes a tough strong alloy.

GUN METAL.Gun metal,a copper-tin CKEL- COPPER. Nickel- copper alloysare alloy, contains approximately 86%-850copper strongbz andharder,than either nickel or copper. (Cu), 7 1/2%-9% ting (SW, 3%-5% zinc (Zn), They have high resistance to corrosion andare 0.3%lead(Pb),0.15%iron(Fe),0.05% strong enough to be substituted for steel when phosphorous (P) and 1% nickel (Ni). As youcan corrosion resistance is of,primary importance. see by the rather complex analysis of this bronze Probably the best known nickel-copper alloyis alloy, the term "copper-tin" is used only to Monet, metal (the trademark for a product of the, designate the major alloy elements. Gun metal International Nickel Company). Monel contains

4-7 to MACHINERY REPAIRMAN 3 & 2

approximately 65% nickel, 30% copper, anda reduced to a gaseous state and depositedon the small percentage of iron, manganese, silicon, and base metal. cobalt. Monetis used for pump shafts and Pure zinc, having a strong anodic potential, internal parts, valve seats and stems, andmany is used to protect the hulls of steel ships against other applications requiring both strength and electrolysis caused by electric currents setup by corrosion resistance. saltwater between dissimilar metals. Zinc plates bolted on the hull, especially thosenear the K-MONEL.K-Monel, also a trademark, is propellers, decompose quite rapidly, but in essentially the same as Monel except that it doing so, greatly reduce localized pitting of the contains about 3% aluminum and is harder and hull steel. stronger than other grades of Monel. K-Monel Another common use of zinc alloys is in stock is very difficult to machine; however,its making die cast parts such as carburetors, small machinability can be improved considerably by engines blocks (lawn mower), andmany small annealingthemetal immediatelybefore parts used in electrical appliances. Thisalloy is machining. K-Monel is used for the shaft sleeves often mistakenly referred toas the copper and on many pumps because of its resistance to the lead alloy called "pot-metal." heat and rubbing action of the packing. There are several other nickel alloys thatyou may find used in Navy equipment. INCONEL, Tin Alloys INCONEL-X; H, S, R, and KR MONELare a few of the more common alloys. Pure tin is seldom used exceptas a coating for food containers, sheet steel and insome Aluminum Alloys applications involving to buildup the metal surfaces of some equipment(motor end bellbearing housings).Several different Aluminum is being used more andmore in grades of tin solder are made by addingeither ship construction because of light weight,easy lead or antimony. One of the primaryuses of workability,goodappearance,andother tin by the Navy is to make bearing babbitt. desirable properties. Pure aluminum is soft and About 5% copper and 10% antimonyare added not very strong. When alloying elements suchas to 85% tin to make this alloy. Thereare various magnesium,copper,nickel, andsiliconare grades of babbitt used in bearings and each grade added, however,a much stronger meta!is may have additional alloying elements added to produced. give the babbitt the properties required. Each of the aluminum alloys has properties developed specifically for a certain type of Lead Alloys application. The hand aluminum alloysare easier to machine than the soft alloys and oftenarc equal to low carbon steel in strength. Lead is probably the heaviest metalwith which you will work. A cubic foot of it weighs Zinc Alloys approximately 700 pounds. It isa grayish color and is amazingly pliable. Itis obtainable in sheets and pigs. The sheets normallyare wound Zinc is a comparatively soft. yet somewhat around a rod and pieces can be cut offquite brittle metal. Its tensile strength is on!), slightly easily. One of the mostcommon uses of lead is greater than that of aluminum. Because of its as an alloying element in soft solder. resistancetocorrosion,zincisusedas a protective coating for less corrosion resistant metals, principally iron and steel. Thereare DESIGNATIONS AND MARKINGS three methods of applying a zinc coating: (1) OF METALS electroplating in a zinc-acid solution; (2) hot dipping, where the metal is dipped intoa bath of Knowledge of the standard designations of molten zinc; (3) sherardizing, where zincis metals and the systems of markingmetals used 4-8 Chapter 4METALS AND PLASTICS

by the Navy and industry isnecessary so that designation for a metal with similiu chemical you can select the proper material for a specific specifications and assigns job. one number that Thereareseveral 'different numbering identifies the metal. This system of dumbering systems currently in use by different trade covers only the composition of the metal and associations, societies, and producers of metals not the condition, quality or form of and alloys that you may find tie metal. on blueprints and Useoftheunifiednumberings' stemis specifications of equipment thatyou will be voluntary by the various metal produce required to repair. It is not -s, and it uncommon to find could be some time beforeany widespread use is several different designations whichrefer to a evident. (Another publication that will metal with the same chemical composition, be useful or to is NAVSEA 0900-LP-038-8010,Ship Metallic find several identical designationswhich refer to Material Comparison and Use Guide.) meters with different chemical compositions.A book published by the Society of Automotive The two major systems used forirk n and Engineers,Inc.(SAE),entitledUnified steel are Society of Automotive Engineers.:(SAE) Numbering System Of Metals and Alloysand CrossIndex and the American Iron and SteelInOitute of ChemicallySimilar (AISI). The aluminum Associationmethod is Specifications,providesaclear andeasily used for aluminum; other nonferrousmeti;ls are understood cross reference from thedesignation designated by the percentage andtypes of of one numbering systemto other systems elements in their composition. The Navy where a similar metal is involved. Some uses of the these methods of designationas a basiifor numbering systems included in the bookthat marking metals so that theycan be identified you may have a need to identify are: readily.

Aluminum Association (AA) FERROUS METAL American Iron and Steel Institute (AISI) DESIGNATIONS

Society of Automotive Engineers (SAE) You should be familiar with the SAEand Aerospace Materials Specifications (AMS) AISIsystems ofsteelclassification.These systems, which arein common use, havea AmericanNationalStandardsInstitute four-digit or five-digit numberto indicate the (ANSI) composition of the steel. The majordifference between the two systems is that the AISIsystem American Society of Mechanical Engineers normally uses a letter before thenumbers to (ASME) show the process used in makingthe steel. The letters used are as follows: BAcidBessemer American Society for Testing and Materials carbon steel; CBasic open-hearthor basic (ASTM) electric furnace carbon steel; andEElectric furnace alloy steel. Example: Copper Development Association (CDA) SAE 10 20 MilitarySpecification(MIL-S-XXXX, AISI C 10 20 MI L-N-XXXX) t FederalSpecification(Q0.N-XX, Basic Open Plain CarbonCarbon QQ-S-XXX) Hearth Carbon Steel Content Steel The unified numbering system, which is A description of these numberingsystems is presented in the book, listsall the different provided in the following paragraphs.

4-9 MACHINERY REPAIRMAN 3 & 2

The first digit normally indicates the basic (2) SAE 1146: This is a resulfurized carbon typeofsteel Thedifferentgroupsare steel (often called free cutting steel). The first de s ikeitt d o wt : digit indicates a carbon steel with an average manganese content of 1.00% (second digit) and an 1 Carbon steel average carbon content of 0.46%. The amount of sulfur added to this steel ranges from 2 Nickel steel 0.08%to0.13%.Thesetwoelements, (manganese and sulfur) in this great a quantity, 3 Nickel-chromium steel make this series of steel one of the easiest machining available. 4Molybdenum steel (3) SAE 4017: The first digit, 4, indicates that this is a molybdenum steel. The second 5 Chromium steel digit, 0, indicates that there is no other equally important alloying element; hence, this is a plain 6 Chromium-vanadium steel molybdenum steel. The last two digits,17, indicate that the average carbon contentis- 8Nickel-chrome-molybdenum steel 0.17%. Other series within the molybdenum steel 9Silicon-manganese steel group are indicated by the second digit. If the seconddigitis1,thesteelis chromium-molybdenum steel; if the second digit The second digit normally indicatesa series within the group. The term "series" in this is 3, the steel is a nickel-chromium-molybdenum connection usually refers to the percentage of steel; if the second digitis 6, the steel is a the majoralio, ing element. Sometimes the nickel-molybdenum steel.In such cases, the second digit gives the actual percentage of the seconddigitdoesnotindicatethe actual chief alloying element; in other cases, the second percentage of the alloying elements, other than digit may indicate the relative position of the molybdenum. series in a group without reference to the actual (4) SAE 51100: This number indicates a percentage. chromium steel (first digit) with approximately 1.0% chromium (second digit) andan average The third, fourth, and fifth digits indicate carbon content of 1.00% (last three digits). The the average carbon content of the steel. The act,i al chromium content of SAE 51100 steels carbon contentisexpressedinpoints; for mayr: from 0.95% to 1.10%. example: 2 points = 0.02%, 20 points = 0.20%, (5) SAE 52100: This number indicates a and 100 points = 1.00%. To make the various chromium steel (first digit) of a higher alloy steels fit into this classification, it is 3ometimes series (second digit) than the SAE 511UO steel necessary to vary the system slightly. However, just described. Note, however, that in thiscase such variations are easily understood ifyou the second digit, 2, merely identifies the series understandthesystem.Let'stakeafew butdoes NOT indicate the percentage of examples: chromium. A 52100 steel will actually have from 1.30% to 1.60% chromium withan average (1) SAE 1035: The first digit is 1, so this isa carbon content of 1.00% (last three digits). carbon steel. The second digit, 0; indicates that There used to be a 7000 series SAE steel, there is no other important alloying element; but under a new system it is no longer used. The hence, this is a PLAIN carbon steel. The next current commonly used tool steels are classified two digits, 35, indicate that the AVERAGE by the American Iron and Steel Institute into percentage of carbon in steels of this series is sevenmajorgroups andeachcommonly 0.35%. There are also small amounts of other accepted group or subgroup is assignedan elements inthissteel,suchas manganese, alphabeticalletter.Methodsof , phosphorus, and sulfur. applications, speck.1 characteristics, and steels

4-10 D.) Chapter 4METALS AND PLASTICS for particular industries are considered in this NONFERROUS METAL DESIGNATIONS type classification of tool steelsas follows: Nonferrous metals are generally Group Symbol and type grouped according to the alloying elements.Examples of these groups are brass, bronze, Water hardening. W copper-nickel, and nickel-copper. Specificdesignations of an Shock resisting . . S alloy are described by theamounts and chemical symbols of the alloying elements.For example, 0Oil hardening Cold work a copper-nickel alloy might be describedas AMedium alloy copper-nickel,70 Cu-30Ni.The 70 Cu DHigh carbon- represents the percentage ofcopper, and the 30 high- chromium Ni represents the percentage ofnickel. Hot work H(H1 to H19 incl. chromium base, Common alloyingelementsandtheir H20 to H39 incl. chemical symbolsare: tungsten base, H40 Aluminum to H59 incl. Molyb- Al denum base) Carbon High-speed J TTungsten base Chromium MMolybdenum base Cr.

Special purpose . ILLow alloy Cobalt Co FCarbon tungsten Mold steels Copper Cu Iron Fe Navyblueprintsandthedrawingsof equipmentfurnishedinthe manufacturers' Lead Pb technical manuals usually specifymaterials by Federal or Military specification numberl. For Manganese Mn example, the couplingon a particular oil isidentifiedas"caststeel, classB, Molybdenum Mo MILS-15083." This particularcast steel does not have any other designation under the various Nickel Ni other metal identification systemsas there are no chemically similar castings. On theother Phosphorus hand, a valve stem which hasa designated material of "MIL-S-862, class 410" (a chromium Silicon Si stainless steel) may becross referenced to several other systems. Some of thechemically similar Sulphur designations for "MIL-S-862, class410" are as follows: Tin Sn SAE = J405 (51410) Federal Spec. = QQ-S-763 (410) Titanium Ti AISI = 410 Tungsten ASTM = A176 (410) ASM = 5504 Vanadium V ASME = SA194 Zinc Zn 4-111 Ish MACHINERY REPAIRMAN 3 & 2

In addition to the type of degignations Designations 2 through 8 are aluminum previously described, a trade name (suchas alloys. In the 2xxx through 8xxx alloygroups, Monel or Inconel) is used sometimes to designate the second digit in the designation indicatesany certain alloys. alloy modification. The last two of the four digitsinthedesignationhave nospecial The Aluminum Association uses a four-digit significancebutserveonly to identify the designation system similar to the SAE/AISI different alloys in the group. systemdescribedforsteels.The numerals assigned with their meaning for the first digits of Inadditiontothefour-digitalloy this system are. designation, a leter or letter/number is included as a temper designation. The temper designation Aluminum (99.00% minimum follows thefour-digitalloy number and is and greater) lxxx separated from it by a dash. Asan example, 2024-T6 is an aluminum-copper alloy, solution Major Alloying Element heat treated, then artificially aged; T6 is the temper designation. The aluminum alloy temper Copper 2xxx designations and their meanings are:

Manganese 3xxx F Fabricated 0 Annealed recrystallized (wrought only) Silicon 4xxx H Strain hardened (wrought only) HI, plusoneor moredigits,strain Magnesium 5xxx hardened only H2, plusoneor moredigits,strain Magnesium and silicon 6xxx hardened then partially annealed H3, plusoneor moredigits,strain Zinc 7xxx hardened then stabilized W Solution heat treatedunstable temper Other element 8xxx T Treated to produce stable tempers other than F, 0, or H The firstdigit indicates the major allaying T2 Annealed (cast only) element and the second digit indicates alloy T3 Solutionheattreated,then cold modifications or impurity limits. The lasttwo worked digits identify the particular alloyor indicate the T4 Solution 1:;,at treated and naturally aluminum purity. agedtoasubstantiallystable condition In the1 xxx group for 99.00% minimum 15 Artificially aged only aluminum, thelasttwodigits indicate the T6 Solutionheattreated,then minimum aluminum percentage to the right of artificially aged the decimal point. The second digitindicates T7 Solution heat treated, then stabilized modifications in impurity limits. If the second T8 Solution heat treated, cold worked, digit in the designation iszero, it indicates that then artificially aged thereisno specialcontrol onindividual T9 Solutionheattreated,artificially impurities; if it is 1 through 9, it indicatessome aged, then cold worked specialcontrol of one or more individual T10 Artificially aged then cold worked impurities. As an example, 1030 indicatesa 99.30% minimum aluminum without special Note that some temper designations apply only control on individual impurities, and1130, to wrought products, others to cast products, 1230, 1330, etc. indicate thesame purity with but most apply to both. A second digitmay specialcontrolof one or more individual appear to the right of the mechanical treatment. impurities. Thisseconddigitindicatesthedegree of

4-12 Chapter 4METALS AND PLASTICS

hardening: 2 is 1/4 hard, 4 is 1/2hard, 6 is 3/4 nonferrous metals the government hard, and 8 is full hard. For example, specification the alloy for the material is often used. Theproducer's 5456-H32isan aluminum/magnesium alloy, name or trademark shown is strain hardened then stabilized, and 1/4 that of the hard. producer who performs the final processingor finishingoperation, beforethematerialis marketed. The commercial designationincludes STANDARD MARKING OF METALS (1) a material designationsuch as an SAE number,anAISInumber,oran ASTM Metals used by the Navyare usually marked (American with Society 01 TestingMaterials) thecontinuousidentification marking specification and (2) a "physical condition" system. This system will be explained and in the quality designationthat is, thedesignation of followingparagraphs.Itis importantto temper or other physical condition approvedby remember that no marking in itselfwill assure you that the correct metal a nationally recognized technical societyor is being used. Often, industrial association suchas the American Iron the markings, provided by themetal producer andSteel will be worn off or cut off and Institute. Some of thephysical you are left with conditions and quality designationsfor various a piece of metal that you are notsure about. metal products are listed here: Additional systems, suchas separate storage areas or racks for different types of metalor CR cold rolled etching on the metal withan electric etcher could save you time later en. CD cold drawn CONTINUOUS IDENTIFICATION HR MARKING hot rolled AQ aircraft quality Thecontinuousidentificationmarking system, which is described in Federal Standards CQ commercial quality is a means for positive identificationof metal products even after some portions have been 1/4H quarter hard used. In the continuousidentification marking system, the markings appear at intervalsof not 1/2H half hard more than 3 feet. Thus, if you cut offa piece of bar stock, the remaining portion will still carry H hard the proper identification. Somemetals, such as small tubing, coils of wire, andsmall bar stock HTQ high tensile quality cannot be marked readily by thismethod. On these items, tags with the requiredmarking AR as rolled information are fastened to the metal. The continuous identificationmarking is HT heat treated actually "printed" on the metalswith a heavy ink that is almost like a paint. G ground The manufacturer is required tomake these markings on materialsbeforedelivery. The marking intervals for various shapesand forms, are specified in the Federal Standards previously IDENTIFICATION OF METALS mentioned. Figure 4-1 shows the normalspacing and layout. The various base metals,such asiron, For copper, lead, zinc, and aluminum have certain metalproducts,thecontinuous identifying characteristicssurface identification appearance marking must include (1) the and weightby whichpersons who work with or producer's name or registeredtrademark and (2) handle these materials readily the commercial designation of distinguish one the material. In from the other. Thereare, however, a number of

4-13 , MACHINERY REPAIRMAN 3 & 2

SANS

1,..0111.101.1.0.1.1.10

1033 AO 11010

NEAT OR PROCESSING NURSER (NORMALLY USED BY MANUFACTURER)

PHYSICAL CONDITION

COMMERCIAL DESIGNATION

SHEET

fRODUCICRII HAMS OR TRAORNARII 6811.1.70011 WTROU

PROOUCER3 RAMC OR TRAORNARK bin..*71101I HMOS

PROCKICIR) NAME OR TRADIMARIt 1111.-S.7000 1411071

IN SOME &SIR COMMERCIAL ontomATIals All U115 I ..... D OP SPECIFICATIONS

28.3/ Figure 4-1. Examples of continuous Identification marking. related alloys which resemble each other and next sections. When performing these tests,you their base metal so closely that they defy should have a known sample of the desired accurate identification by simple means. material and make a comparison. When using There are other means of rapid identification these tests, you will need good lighting,a strong of metals. These methods by nomeans provide permanent magnet, and access to a. lathe. A positive identification and should not be used in word of cautionhen performing these tests: criticalsituations where a specific metal is DO NOT be sati fied with the results of only desired. Some of the methods that will be one test; use asany tests as possible so that discussed here are magnet tests, chip tests, file you can incre the chances of making an tests, acid reaction tests, and spark tests. The accurate identificion. latter two are the most commonly used bythe Navy. Table 4-2 contains information relatedto SPARK TEST surfaceappearance, magnetic reaction, lathe chip test, and file test. The acid test and the ise identification of a metal spark test are discussed in more ;detail in the by observing the color, e, and the shape of the

4-14 Chapter 4METALS ANDPLASTICS

Table 4.2. Rapid Identification ofMetals

Metal Surface AppearanceReaction to a Lathe Chip test Color of freshly or markings Magnet 4 filed surface White cast iron Dull gray Strong Short, crumbly chipsSilvery white Gray cast iron Dull gray Strong Short, crumbly chipsLight silvery gray Light gray to white Aluminum None Easily cut, smooth dull or brilliant long chips White Yellow to green or Brass None Smooth long chips Reddish yellow to brown slightly brittle yellowish white

Bronze Red to brown None Short crumbly Reddish yellow to chips yellowish white Smooth; red brown Copper None Smooth long pliable Bright copper to green (oxides) chips color Smooth; gray to Copper-nickel None Smooth, continuous Bright silvery yellow or yellowish chips green white White to gray; Lead None Cut by knife, any smooth, velvety shape chip White Dark gray; smooth; Nickel Medium Cuts easily, smooth Bright silvery sometimes green continuous chip white (oxides)

Nickel-copper Dark gray, smooth Very slight Continuous chip; tough to cut Light gray Dark gray; may be Plain carbon steel Strong Varies depending Bright silvery rusty upon carbon content gray Stainless steel (18-8) Dark gray; dull to None (faint if Varies depending Bright silvery (25-20) "Note 1 below" brilliant; usually severely cold upon heat treatment gray clean worked) Whitish blue, may Zinc None Easily cut; long be mottled stringy chips White 1. Stainless steels that have less than 26 percent alloying elementsreact to magnet. spark stream given off when themetal is held unknown specimens againstagrinding wheel. This method of withthatof sample specimens of known composition.Itis the identification is adequate for mostmachine shop purposes. When the exact composition of practice in many shops to maintainspecimens of a knowncompositionforcomparisonwith metal must be known,a chemical analysis must unknown samples. be made. Identification ofmetals by the spark Proper lighting conditions test method requires considerable are essential for experience. good spark testing practice. Thetest should be To gainthisexperience, you will need to performed in an area where practice by comparing the spark there is enough stream of light,but harsh or glaring lightshould be

4-15 MACHINERY REPAIRMAN 3 & 2

avoided. In many shipsyou may find that a carbon. The swellingor buds in the spark line spark test cabinet has been erected.Generally, indicate nickel with molybdenum. Part Bof these cabinets consist ofa box mounted on the figure 4-2 shows shafts and sprigs top of a and have or sparklers a dark painted which indicate a high carbon content. PartC interior. Inside the cabineta is shows shafts, forks, and sprigs which indicate mounted. Test specimens of known composition a . medium carbon content. Part D showsshafts are contained inshelves at the end of the and forks which indicatea low carbon content. cabinet. Where possible, the testing area should The greater the amount of carbon presentin be away from heavy drafts of air. Airdrafts can a steel; the greater the intensity of bursting that change the tail of the spark streamand may willtakeplaceinthespark result in improper identification of stream. To the sample. understand the cause of the bursts,remember Speed and 'pressure are factors thatneed to be considered in making the that while the spark is glowing and incontact spark test. The with the oxygen of the air, the carbonpresent in faster the speed of the wheel, the largerand longer the spark stream will the particle is burned to carbon dioxide(CO2). be. (Generally As the solid carbon combines withoxygen to speaking, a suitable grinding wheelfor spark form CO2 in the gaseous state, the testing is an 8-inch wheel turning 3600 increase in rpm. volume builds up a pressure that isrelieved by This provides a surface speed of 7,537feet per an explosion of the particle. An examination of minute.) The pressure of the pieceagainst the the small steel particles undera microscope wheel has similar effects: the'more pressure when they are cold revealsa hollow sphere with applied to the test piece, the largerand longer one end completely blown away. the spark stream. Hold the test piece lightlybut firmlyagainstthe wheel with just enough pressure to prevent the piece from bouncing. Remember that you must applythe same amount of pressure to the test specimenas to the sample you are testing. The grain size of the grinding wheelshould be from 301a 60 grains. It is very important to remember that the wheel must be cleanat all times. A wheel loaded with particlesof metal will give off a spark stream of the type ofmetal in the wheel, mixed with the sparkstream of the metal being tested. This will result inserious confusion as to-the true nature of the metal.The wheel must be dressed before sparktesting and before each new test of a different metal.

The spark test is made by holdinga sample of the material against a .The sparks given off, or the lack of sparks,assist in identifying the metal. The length ofthe spark stream, its color, and the type of sparksare the features for which you should look.There are four fundamental spark forms producedwhen a sample of metal is held againsta power grinder. (See fig. 4-2.) Part A shows shafts, bud,break, andarrow.Thearroworspearheadis characteristicofmolybdenum,ametallic element of the chromium group which resembles iron and is used for forming steel-like alloys 11.371X with Figure 4-2.Fundamental spark forms.

416 Chapter 4METALS AND PLASTICS

Steels having the same carbon content but which may occur at any place in low different alloying elements carbon are not always easily steel are forked, while in high carbonsteel the identified because alloying elements affectthe sparklers are small and repeating and carrierlines,the some of bursts,orthe forms of the shafts may be forked. Both will producea characteristic bursts in the spark picture.The white spark stream. effect of the alloying elementmay retard or accelerate the carbon sparkor make the carrier White cast iron producesa spark stream line lighter or darker in color. Molybdenum,for approximately 20 inches in length (see fig. 4-3). example, appears as a detached, orange-colored, The volume of sparks is small withmany small, spearhead on the end of the carrier line.Nickel repeatingsparklers. The color of the spark seems to suppress the effect of the carbon burst. stream close to the wheel is red, while theouter But the nickel spark can be identified bytiny end of the stream is straw-colored. blocks of brilliant white light. Siliconsuppresses Gray cast iron produces the carbon burst even a stream of sparks more than nickel. When about 25 inches in length. It is small involume silicon is present, the carrier line usuallyends with fewer sparklers than from white abruptly in a flash of white light. cast iron. The sparklers are small and repeating.Part of the stream near the grinding wheel is red, and the To make the spark test, hold the pieceof outer end of the stream is straw-colored. metal on the wheel in sucha manner as to throw the spark stream about 12 inchesat a right angle The malleable iron spark test will producea to your line of vision. You will needto spend a spark stream about 30 inches in length.It is of little time to discover at just whatpressure you moderate volume withmany small, repeating must hold the sample to geta stream of this sparklers toward the end of the stream. The lengthwithoutreducing thespeed of the entire stream is straw-colored. grinder. It is important thatyou do not press The wrought iron spark test produces too hard because the pressure will increase a the spark stream about 65 inches in length.The temperature of the spark stream and the burst. stream is of large volume with It will also give the a few sparklers. appearance of a higher The sparklers show up toward the endof the carbon content than that of the metalactually stream and are forked. The stream next to the being tested. After practicing to get the feel of grinding wheel is straw-colored, while theouter correct pressure on the wheel untilyou are sure end of the stream is a bright red. you have it, select a couple of samples of metal with widely varying characteristics; for.example, Stainlesssteelproduces a spark stream low-carbon steel and high-carbon steel:Hold approximately 50 inches in length, of moderate first one and then the other againstthe wheel, volume, and with few sparklers. Thesparklers always being careful to strike thesame portion are forked. The stream next to the wheel is of the wheel with each piece. Withyour eyes straw-colored, while at the end it is white. focused at a point about one-third thedistance from the Nickel produces a spark stream only about tail end of the stream of sparks, 10 inches in length. It is small involume and watching only those sparks whichcross the line orange in color. The sparks form wavy streaks of vision, you will find that aftera little while with no sparklers. you will form a mental image of the individual spark. After you can fix the spark imagein Monel metal formsa spark stream almost mind, you are ready to examine thewhole spark identical to that of nickel and must be identified picture. by other means. Copper, brass,bronze, and lead form no sparks on the grindingwheel, but they Notice that the spark stream is long (about are easily identified by other means, suchas 70 inches normally) and thatthe volume is color, appearance, and chip tests. moderately large in low-carbonsteel, while in You will find the spark testseasy and high carbon steel the stream is shorter (about55 convenient to make. They requireno special inches) and large in volume. The fewsparklers equipment andareadaptableto most any 417 1 I MACHINERY REPAIRMAN 3 & 2

LOW CARBON AND CAST STEEL MALLEABLE IRON

GRAY CAST IRON WROUGHT IRON

HIGH CARBON STEEL STAINLESS STEEL

WHITE CAST IRON NICKEL

11.37X Figure 4-3.Spark pictures formed bycommon metals. situation. Here again, experience isthe best teacher. following safety precautions must be observedin using or handling acids ofany type.

ACID TEST NEVER open more thanone container of acid at one time. The nitric acid test is the mostcommonly used for metal identification by theNavy today; In mixing, alwayspour acid slowly into it is used only in noncritical situations. Forrapid water. NEVER pour water into acidbecause an identification of metal, the nitric acidtest is one explosion is likely tooccur. of the easiest tests touse and requires no special training in chemistry to perform. Itis most If any acid is spilled, dilute with helpful in distinguishing between plenty stainless steel, of water to weaken itso that it can be safely Monel, copper-nickel, and carbonsteels. The swabbed up and disposed of.,

4-18 Chapter 4METALS AND PLASTICS

If an acid is spilledon your skin, wash metals to nitric acid. There immediately with large quantities of are acid test kite water. Then available containing several differentsolutions o wash with a solution of borax andwater. identify the different metals. Someof the kit can identify between the different seriesof Wear CLEAR-LENS safety gogglesto stainless steels (300, 400 series).Low alloy ensure the detection of the reaction of metal to steels, nickel steels, and various an acid test which may be evidenced by bronze alloys are a color alsoidentifiedquickly with thesetests. A change, the formation ofa deposit, or the chemical laboratory is available in development of a spot. most large repair ships and shore repairfacilities. The personnel assigned are also available Conduct tests in a well-ventilated to identify area. various metals in more criticalsituations or when a greater degree ofaccuracy is required on To perform the nitric acidtest, place one or a repair job. two drops of concentrated (full strength)nitric acid on a metal surface that has beencleaned by grinding or filing. Observe the resulting reaction HEAT TREATMENT (if any) for about 2 minutes. Then, addthree or four drops of water, one drop ata time, and Heattreatmentis continue obseiving the reaction. If theoperationor there is no combination of operations, includingheating reaction at all, the test materialmay be one of and cooling of a metal in its solid the stainless steels. A reaction that state, to results in a developorenhanceaparticulardesirable broVm-colored liquid indicatesa plain carbon mechanical steel. A reaction producing property,suchashardness, a brown to black toughness,machinability,or uniformity color indicates a gray cast ironor one of the of alloy steels containing strength. The theory of heattreatment is based as its principal element upon the effect that the rate of heating, degree either chromium, molybdenum, or vanadium. of heat, and the rate of coolinghave on the Nickel steel reacts to the nitricacid test by molecular structure of a metal. forming a brown to greenish-blackliquid, while a steel containing tungsten reacts slowly to form There are several forms of heat a brown-colored liquid with a yellow sediment. treating. The forms commonly used forferrous metals are: When nonferrous metalsare,..e.loysare annealing, normalizing, hardening, subjected to the nitric acid test; , rust: id of the and case-hardening. Detailedprocedures for the brown-black colors thatusua Ppi,...ar when various heat treatments of metals ferrous metals are tested, various and the si,acies of green theories behind them are beyond thescope of ,'and blue appear as the materialdissolves. Except this manual. However, since with nickel and Monel, the reaction you will run across is vigorous. the terms from time to time andwill probably The reaction of nitric acidon nickel proceeds perform some of the heat treatment slowly, developing a pale processes green color. On Monel, under the supervision ofan MR1 or MRC, we the reaction takes place at about thesame rate will discuss some of the general as on ferrous metals, but the characteristic color terminology. of theliquidisgreenish-blue.Brassreacts vigorously with the test material changingto a ANNEALING green color. Tin bronze, aluminum bronze, and copper all react vigorously in the nitric acid test The chief purposes of annealing with the liquid changing to are (1) to a blue-green color. relieve internal strains and (2)to make a metal Aluminum andmagnesiumalloys,lead, soft enough for machining. lead-silver, and lead-tin Annealing is the alloys are soluble in process of heating to and holding ata suitable nitric acid, but the blue or green color islacking. temperature and then cooling at From the information given thus far, a suitable rate, it is forsuchpurposesasreducinghardness, easy to see that you will need considerable visual improving ,machinability, skill to identify the facilitatingcold many different reactions of working, producing a desiredmicrostructure or 4-19 MACHINERY REPAIRMAN 3 & 2

obtaining desired mechanical, physicalor other 2150°F. Hold at this temperaturea suitable properties. time, depending on thickness. Follow by rapid Besides rendering metal more workable, cooling in a quenching medium. annealing can also be used to alter other physical properties, such as magnetism and electrical BRASS: Annealing to relieve stressmay be conductivity.Annealingisoftenusedfor accomplished at a temperature as lowas 600°F. softening nonferrous alloys andpure metals' Fulleranneals may be accomplished with after they have been hardened by cold work. increased temperatures. Larger grain size and Someofthesealloysrequireannealing lossof strengthwillresultfrom too high operations which are different from those for temperatures. Do NOT anneal at temperatures steel. exceeding1300°F.Brass should beslowly For ferrous metals, the annealing method cooled to room temperature. Eitherwrap the mostcommonlyused,ifacontrolled part with heat retarding cloth or bury it in atmosphere furnace is not available, is to place slaked lime or other heat retarding material. the metal in a cast iron box andcover it with sand or fire clay. Packing this material around BRONZE: Heat to 1400°F. Cool inan open the metal prevents oxidation. The box is then furnace to 500°F or place in apan to avoid placed in the furnace, heated to theproper uneven cooling caused by . temperature, held there for a sufficient period, and then allowed to cool slowly in the sealed NORMALIZING furnace. Instructions for annealing themore common Normalizing isthe process of heating a metals: ferrous alloy to a suitable temperature abovethe critical temperature or transformationrange (see CAST IRON: Heat slowly to between 1400° section on hardening) and then cooling in still and 1800 °F, depending on composition. Hold at air.Normalizing relieves stresses and strains the specific temperature for 30 minute: and caused by welding, forging anduneven cooling. then allow the metal to cool slowly in the Normalizing also removes the effects of previous furnace or annealing box. heat treatments.

STAINLESS STEEL (Austenitic): For full HARDENING annealing, heat to between 1850° and 2050°F. Cool rapidly. For partial annealing, heat to Cutting tools, , twist drills, andmany between 1600° and 1700° F. other pieces of equipment and tools mustbe COPPER: Heat to 925°F. Quench inwater. hardened to enable them to retain. theircutting A temperature as low as 500°F will relievemost edges. Surfaces of roller bearings, parallel blocks, of the stresses and strains. and armor plate must be hardened toprevent wear or penetration. Metals and alloyscan be ZINC: Heat to 400°F. Cool inopen, still air. hardenedinseveralways;abrief general description of one method of hardeningfollows. ALUMINUM: Heat to 750°F. Cool inopen air. This reduces hardness and strength but Each steel has a critical temperatureat increases electrical conductivity. which a marked change willoccur in the grain structure and physical properties. This critical NICKEL-COPPER ALLOYS INCLUDING temperaturevariesaccordingto the carbon MONEL: Heat to between 1400° and 1450°F. content of the steel. To be hardened, steel must Cool by quenching in water or oil. be heated to a littlemore than this critical temperatureto ensure thatevery point in it will NICKEL-MOLYBDENUM-IRON and have reached critical temperature andto allow NICKEL-MOLYBDENUM-CHROMIUM for some slight loss of heat when the metalis ALLOYS (Stellite): Heat to between 2100'and transferred from the furnaceto the cooling I Li, 4-20 Chapter 4METALS AND PLASTICS medium. Itis then cooled rapidly by being hardening is to (1) carburize the material(an quenched in oil, freshwater,or brine. Quenching addition of carbon during the firmly ) fixesthe treatment), (2) structuralchanges which allow it to cool slowly, (3) reheat,and (4) occurred during heating and thuscauses thd hgden in water. metal to remain hard. Small pieces such as bolts, nuts, and screws, however, can be dumpedinto water as soon as they are taken out of the carburizing If allowed to cool too slowly, tilt,metal will furnace. lose its hardness. On the other han to prevent too rapid quenching whichw. . resultin warping and cracking, it is sometimesnecessary HARDNESS TESTS to use oil instead of freshwateror saltwLter for high carbon andalloysteels. Saltwater,as A number of tests are used tomeasure the opposedtofreshwater,producesgreater hardness. physical properties of metals andto determine whethera metalmeetsspecification requirements. Some of themore common tests To prevent hardandsoftspots when are hardness tests, tensile 'strength tests, shear quenching, hold the part with a set of strength tests, bend tests,fatigue tests, and made with long handles and gripsor jaws that compression tests. Of primary importance will hold the part firmly but with to a a minimum Machinery Repairman is the hardnesstest. amount of surface contact. Whenyou submerge the part in the cooling medium, rapidlymove it Mostmetalspossesssomedegreeof up and down while moving it around the cooling hardnessthat is, the ability to resistpenetration mediumcontainerin a clockwiseor by another material. Many tests forhardness are counterclockwise erection. used; the simplest is the file hardnesstest. While fair estimates of hardnesscan be made by an TEMPERING experiencedworkman,moreconsistent quantitative measurementsare obtained with The tempering process relievesstrains that standardhardnesstestingequipment. Such are brought about in steel during the hardening equipment eliminatesthevariables of size, process. Tempering makes the metal tougher and shape, and hardness of the file selected,and of lessbrittle.Temperingisaccomplished by the speed, pressure, and angles ofthe file used heating the hardened steel toa temperature by a workman when conductinga test. Before belowthecriticalrange,holdingthis discussing the hardness testequipment, let us temperature for a sufficient time topenetrate consider hardness itself, and the valueof such the whole piece, and then coolingthe piece. In information to a Machinery Repairman. thisprocess,ductilityandtoughnessare improved, but tensile strength andhardness are Hardness has been defined invarious ways: reduced. resistance to penetration, resistanceto abrasion, resistancetomachinetoolcutting,and CASE HARDENING resistance to bending (stiffness) bywrought products. Except for resistanceto penetration, Case hardening is a process of heattreating these characteristics of hardnessare not readily by which a hard skin is formedon metal, while measurable. Consequently, most hardnesstests the inner part remains relatively softand tough. are based on the principle thata hard material A metal thatis originally low in carbon is will penetrate a softerone. In a scientific sense, packed in a substance high incarbon content then, hardness iss measure of the resistance of a and heated above the criticalrange. The case material to penetrationor indentation by an hardening furnace must givea uniform heat. The indenter of fixed size and geometricalshape, under a specific load. length of time the piece is left in theoven at this high heat determines the depthto which carbon The information obtained from is absorbed. A commonly used a hardness method of case test has many uses. It may be usedto compare

4-21 1 ) MACHINERY REPAIRMAN 3 & 2

alloys and the effects of various heat treatments on them. Hardness tests are useful as a rapid, SMALL WEIGHTS nondestructivemethodforinspecting- and POINTER controlling certain materia7- andprocesses and HARDNESS toensurethatheat-treatedobjectshave DIAL developed the hardness desired or specified. The results of hardness tests are useful not only for LONG comparative purposes, but also for estimating NEEDLE otherproperties.For example,thetensile strength of carbon and low-alloy steelscan be INDENTER estimated from the hardness test number. There isalso a relationship between hardness and endurance or fatigue characteristics of certain ANVIL steels. ELEVATING Hardness may be measured bymany types WHEEL of instruments. The mostcommon arethe Rockwell and Brinell hardness testers. Other KNURLED hardness tests include the Vickers, Eberbach, ZERO Monotroh, Tukon, and Scleroscope. Since there ADJUSTER are many tests and the hardness numbers derived are not equivalent, the hardness numbers must be designated according to the test andthe scale used in the test. Since youare more likely to have access to a Rockwell tester thanany other, DEPRESSOR MAJOR LOAD this method is discussed in detail. The essential BAR LIFTING CRANK HANDLE differences between the Rockwell and Brinell 102.90X tests will also be discussed in the sections which Figure 44.Standard Rockwell hardnesstesting follow. Ih addition, the Scleroscope and Vickers machine. hardness tests will be covered briefly.

ROCKWELL HARDNESS TEST conjunction with a 150kilogram (kg) weight to make impressions in hard metals. The hardness Of all the hardness tests, the Rockwell is the number obtained is designated Rockwell C (Re). one most frequently used. The basic principle of For softer metals, the penetrator isa 1/16-inch the Rockwell test (like that of the Brinell, steel ball used in conjunction witha 100-kg Vickers,Eberbach,Tukron, and Monotron weight. A hardness number obtained under these tests) is that a hard material will penetratea conditions is designated Rockwell B (Rb). softer one. This test operates on the principle of Figure4-5illustratestheprinciple of measuring the indentation, ina test piece of indenter hardness tests. Although the conical metal, made by a ball or cone ofa specified size penetrator is shown, the principle is thesame for which is being forced against the test piece of aballpenetrator.(The geometry of the metal with specified pressure. In the Rockwell indentations will, of course, differ slightly.) ,tester shown in figure 4-4, the hardness number With the Rockwell tester,a deadweight, is obtained by measuring the depression made acting through a series of levers, is used by to press a hardenedsteelball(indenter) or a the ball or cone into the surface of the metalto spheroconical diamond penetrator ofa given size be tested. Then the depth ofpenetration is under a given pressure. measured. The softer the metal being tested, the deeper the penetration will be undera given With the normal Rockwell tester snuwn, the load. The average depth of penetrationon 120°spheroconicalpenetratorisusedin samples of very soft steel is only about 0.008

4-22 1Zi Chapter 4METALS AND PLASTICS

THIS INCREASEINCREASE IN DEPTH OF PENETRATION, CAUSED BY APPLICATION OF MAJOR LOAD, FORMS THE BASIS FOR THE ROCKWELL HARDNESS TESTER READINGS.

128.87X Figure 46.Principle of Rockwell hardness test. inch. The hardnessisindicated on adial, load applied to perform the test and in the kind calibrated in the Rockwell B and the Rockwell C of scale used to interpret the results. When the hardness scales. The harder the metal, the higher major loads on the normal testerare 100 and the Rockwell number will be. Ferrous metalsare 150 kg, the major loads on the superficiallester usually tested with the spheroconical penetrator, are 15, 30, and 45 kg. One division on the dial with hardness numbers being read from the gage of the normal tester represents a vertical Rockwell C scale. The steel ballis used for displacement of the indenter of 0.002 millimeter nonferrous metals and the results are readon the (mm). One division of the dialgage of the B scale. superficialtesterrepresentsavertical With most indenter-type hardness tests, the displacement of the indenter of 0.001mm. metal being tested must be sufficiently thick to Hardness scalesfor the Rockwell superficial avoid bulging or marking the opposite side. The tester are the N and T scales. The N scale is used specimen thickness should be at least 10 times for materials of such hardness that,were they of the depth of penetration. It is also essential that sufficient thickness, they would be tested with the surface of the specimen be flat and clean. the normal tester using the C scale. The T scale When hardnesstestsarenecessary on thin is comparable to the B scale used with the material, a superficial Rockwell tester should be normal tester. In other respects the normal and used. superficial Rockwell testers are much alike. The Rockwell superficial tester differs from Assuming the sample is properly prepared the normal Rockwell tester in the amount of and the appropriate penetrator and weightsare

4-23 1 MACHINERY REPAIRMAN 3 & 2

selected, the following step-by-step procedure r or ferrous metals, a 3,000-kilogram loadis will indicate how a Rockwell tester is used: applie-I. For nonferrous metals, the load is50Q) kilograms. In general, pressure is appliedto 1.Place the piece to be testedon the ferrous metals for 10 seconds, while 30 seconds testing table, or anvil. isrequired for nonferrous metals. After the 2. Turn the wheel tha elevates thetesting pressure has been applied for the appropriate table until the piece to be tested comes in time, the diameter of the depression producedis contact with the testing cone or ball. Continue measured with a microscope havingan ocular to turn the elevating wheel until thesmall scale. pointer on the indicatinggage is nearly vertical and slightly to the right of the dot. 3. Watch the long pointer The Brinell hardness number (Bhn) isthe on the gage; ratio of the load in kilograms to theimpressed continue raising the work with theelevating surface area in square millimeters.This number wheeluntilthelong pointerisnearly is found by measuring the distance the ballis uprightwithinapproximatelyfivedivisions, forced, under a specified plus or minus, on the scale. This pressure, into the test step of the piece. The greater the distance, the softerthe procedure sets the minor load. metal,and the lower the 4. Turn the zero adjuster, located Brinellhardness below number will be. The width of the indentationis the elevating wheel, to set the dialzero behind measured with a microscope, and the hardness the pointer. number corresponding to this width is found by 5. Tap the depressor bar downwardto consulting a chart or table. release the weights and apply the majorload. Watch the pointer until itcomes to rest. 6. Turn the The Brinell hardness machine is of greatest crank handle upwarda-'d value in testing soft and medium-hardmetals forward, thereby removing the major butnot and in testing large pieces. On hard steelthe the minor load. This will leave thepenetrator in imprint of the ball is so small that it is difficult contactwith the specimen butnot under to read. pressure. 7. Observe where the pointernow comes to SCLEROSCOPE HARDNESS TEST rest and read the Rockwell hardness numberon the dial. If the test has been madewith the If you place a mattress 1/16-inch ball and a 100-kilogram on the deck and drop weight, the two rubber balls from thesame height, one on reading is taken from the red,or B, scale. If the the mattress and one test on the deck, the one has been made with the spheroconical dropped on the deck will bounce higher.The penetrator and a weight of 150 kilograms,the reason is that the deck is the harder of the two reading is taken from the black, or C scale. (In surfaces; this is the principleupon which the the first example the number is prefixedby Rb, Scleroscope works. When using the Scleroscope and in the latter instance by Rc.) hardness test, drop a diamond-pointedhammer 8.Turn the handwheel to lower the anvil. through a guiding glass tube Then remove the test specimen. onto the test piece and check the rebound (bounce)on a scale. The harder the metal. being tested, the BRINELL HARDNESS TEST higher the hammer will rebound, and the higher will bethe number on the scale. The Scleroscope isportable TheBrinellhardnesstesting machine and can be used to test the hardnessof pieces provides a convenient and reliable hardnesstest. too large to be placed on the anvil The machine is not suitable, however, for thin or tables of or othermachines.SincetheScleroscopeis smallpieces.This machine hasavertical portable and can be held in hydraulic press design and is generally your hand, it can be hand used to test the hardness of largeguns and operated. A lever is used to apply the loadwhich marineandother forces a 10-millimeter diameter hardened that cannot be steel mounted onstationarymachines.Another or tungsten-carbide ball into the test specimen. advantage of the Scleroscope is thatit can be 4-24 1 4) Chapter 4METALS AND PLASTICS

used without damaging finished surfaces.The of metal being tested and tocompare the chief disadvantage, however, of this machine,is hardness of various metals on hand. Thus,when its inaccuracy. The accuracy of the Scleroscope identification of metal by othermeans is not is affected by the following factors: . possible, you can use a file to determinethe relative hardness of various metals. The 1. results Small pieces do not have thenecessary of such a test may enable you to selecta metal backing and cannot be held rigidly enoughto more suitabl' for the job being performed. give accurate readings. The file hardness test is simple 2. to perform. If large sections are not rigid, if theyare You may hold the metal being tested inyour oddly shaped, if they have overhangingsections, hand and rested on a bench,or put it in a vise. or if they are hollow, the readings may be in Grasp the file with your index finger extended error. along the file and apply the file slowlybut 3.If oil- harcened partsare tested, oil may firmly to the surface being tested. creep up the glass tine and interfere with the If the materialiscut by the drop of the diamond-pointed hammer in filewith the extreme ease and tends to clog thespaces instrument, thus causing an error. between the file teeth, it is VERY SOFT. Ifthe material offers some resistance to the VICKERS HARDNESS TEST cutting action of the file and tends to clog the fileteeth, it is SOFT. If the material offersconsiderable The -Vickers test measures hardness bya resistance to the file but can be filed by repeated method similar to that of the Brinell test. The effort, it is HARD and mayor may not have indenter,however,isnotaball,buta been heattreated.If the material can be square-based diamond pyramid, which makes it removed only by extreme effort and insmall accurate for testing thin sheets as wellas the quantities by the file teeth, it is VERY HARD hardest steels. and has probably been heat treated. If thefile Up to an approximate hardness numberof slides over the material and the file teethare 300, the results of the Vickers and the Brinell dulled, the material is EXTREMELY HARDand tests are about the same. Above 300, Brinell has been heat treated. accuracy becomes progressively lower.This The file test is not a scientific method.It divergence represents a weakness in theBrinell should not be used when positive identification methoda weakness that is the result of the of metal is necessaryor when an accurate tendency of the Brinell indenter ball to flatten measurement of hardnessisrequired. Tests under heavy loads. For thisreason, Brinell already described should be used forpositive numbers over 600 are considered to beof identification of metals. Special machines,such doubtful reliability. as the Rockwell and Brinell testers, should be usedwhenItisnecessarytodetermine If a ship has one type of hardness tester and accurately the hardness of the material. the specifications indicated by the blueprintare for another type, a conversion table, suchas PLASTICS table 4-3, may be used to convert the reading. Plastic materials are being increasingly File Hardness Test used aboard ship. In some respects, theytend to surpass structural metals; plastic has proved to Hardnesstests are commonly usedto be shock resistant, not susceptibleto saltwater determine the ability of a material under test to corrosion, and in casting It lends Itselfto mass resistabrasionorpenetrationbyanother production and uniformity of end product. material.Many methods haveevolvedfor measuring the. hardness of metal. The simplest CHARACTERISTICS method is the file hardness test. This testcannot be used to make positive identification apetals Plastics are formed from organic materials, but can be used to get a general idea ofthe type generally with some form of carbonas their 4-251 i MACHINERY REPAIRMAN 3 & 2

Table 4-3.-Hardness Conversion Chart (Ferrous Metals)

_ Tensile Tensile Brinnel Rockwell Strength Brinnel Rockwell Strength Hardness Hardness Approximate Hardness Hardness Approximat No. 3,000 kg No. C Scale X 1,000 psi No. 3,000 kg No. C Scale X 1,000 psi

70C 477 50.3C 234 69C 461 48.8C 226 . 68C 444 47.2C 218

67C 429 45.7C 210

767 66.4C 376 415 44.5C 203

757 65.9C 371 401 43.1C 196

745 65.3C 365 388 41.8C 190 733 64.7C 359 375, 40.4C 184

722 64.0C 354 363 39.1C 178

710 63.3C 348 352 37.9C 172

698 62.5C 342 341 36.6C 167

682 61.7C 334 331 35.5C 162

670 61.0C 328 321 34.3C 157

653 60.00 320 311 33.1C 152

638 59.2C 313 302 32.1C 148

627 58.7C 307 293 30.9C 144

601 57.3C 294 285 29.9C 140

578 56.0C 283 277 28.8C 136

555 54.7C 272 269 27.6C 132

534 53.5C 262 262 26.6C 128'

524 52.1C 257 255 25.3C 125

495 51.0C 243

4-26 Chapter 4METALS AND PLASTICS

Table 4-3.Hardness Conversion Chart (Ferrous Metals)Continued

Brinell Rockwell Brinell Rockwell Hardness Hardness Hardness Hardness No. 500 kg No. IT Scale No. 500 kg No. B Scale

201 99.0B 143 85.0B

195 98.2B 140 82.9B

189 97.3B 135 80.8B

184 96.4B 130 80.0B

179 95.5B 120 75.B

175 94.6B 110 70.0B

171 93.8B 100 63.5B

167 92.8B 95 60.0B

164 91.9B 90 56.0B

161 90.7B 85 52.0B

158 90.0B 80 47.0B

156 89.0B 75 41.0B ... 153 87.8B 70 34.0B

149 86.8B 65 26.0B 146 86.0B basicelement.Plasticsarereferredtoas plastics, to know which of these twoyou are synthetic material, but this does not necessarily using. mean that they are inferior to natural material. Thermosettings are tough, brittle, and heat On the contrary, they have been designed to hardened. When placed ina flame, they will not perform particular functions thatno natural bum readily, if at all. Thermosettingsare so hard material can perform. Plasticscan be obtained in they resist the penetration ofa knife blade; any a variety of colors, shapes, ,and formssome are such attempt will dull the blade. If the plasticis as tough, but not so hard, as steel; some are as immersed in. hot water and allowedto remain, it pliable as rubber; some aremore transparent will neither absorb moisturenor soften. then glass; and some are lighter than aluminum. Thermoplastics, on the other hand,when Plasticmaterialsfallintotwo major exposed to heat, become soft and pliable,or divisionsTHERMOSETTINGS and THERMO- even melt. When cooled, they retain the shape PLASTICSandit isnecessary,ifyou that they took under the application of heat. are going to perform any kind of shopworkon Some thermoplastics willeven absorb a small

4-27 MACHINERY REPAIRMAN 3 & 2

Table 44.Major Groups of Plastics

Plastic Trade Names in () Advantages and Examples of Uses Disadvantages

THERMOPLASTICS

Acrylic Formability; good impact strength; good aging Softening point of 170° (Lucite, Plexiglass) and weathering resistance; high transpar- to 220°F; low ency, shatter-resistance, rigidity. Used scratch resistance. for lenses, dials, etc. Cellulose nitrate Ease of fabrication; relatively high impact Extreme flammabil- (Celluloid) strength and toughness; good dimensional ity; poor electrical stability and resilience; low moisture insulating prop- absorption. Used for tool handles, erties; harder with heads, clock dials, etc. age; low heat dis- tortion point. Polyamide High resistance to distortion under load at Absorption of water; (Nylon) temperatures up to 300°F; high tensile large coefficient of strength, excellent impact strength at expansion; relatively normal temperatures; does not become high cost; weather- brittle at temperatures as low as minus ing resistance poor. 70°F; excellent resistance to gasoline and oil; low coefficient of friction on metals. Used for synthetic textiles, special types of bearings, etc. Polyethylene Inert to many solvents and corrosive chemi- Low tensile, com- (Polythene) cals; flexible and tough over wide tempera- pressive, flexural hire range, remains so at temperatures as strength; very high low as minus 100°F; unusually low moisture elongation at nor- absorption and permeability; high electrical mal temperatures; resistance; dimensionally stable at normal subject to spontan- temperatures; ease of ; low cost. eous cracking when Used for wire and cable insulation, and stored in contact acid resistant clothing. with alcohols, toluene, and sili- cone grease, etc. ; softens at tem- peratures above 200°F; ppn abrasion and cut resistance; cannot be bonded unless given special surface treatment.

28.37.02 1 0 -4 -4, 428 Chapter 4METALS AND PLASTICS

Table 44Major Groups of PlasticsContinued

Plastic Trade Names in () Advantages and Examples of Uses Disadvantages

THERMOPLASTICS Polytetrafluoroethylene Extreme chemical inertness; high heatre- kTeflon) Not easily cemented; sistance; nonadhesive; tough; low coefficient cannot be molded by of friction. Used for preformedpacking and usual methods; gen- gaskets. erates toxic fumes at high tempera- tures; high cost.

THERMOSETTINGPLASTICS

Phenolformaldehyde Better permanence characteristics than Difficult to mold when (Bakelite, Durez, most plastics; may be used at temperatures Resinox) filled for greatest from 250° to 475°F; good agingresistance; impact strength, or good electrical insulating properties;not when in sections less readily flammable, does not supportcom- than 3/32-inch thick; bustion; inserts can be firmly embedded; can be expanded or strong, light; low water absorption; low contracted by un- thermal conductivity; good chemicalre- usually wet or dry sistance; economical in production ofcom- atmosphere. plex shapes; free from cold flow; relatively insensitive to temperature; low coefficient of thermal expansion; no change indimen- sions under a load for a long time; doesnot soften at high temperatures or become brittle down to minus 60°F; inexpensive. Used for handles, telephone equipment, electridal insulators, etc. Urea-formaldehyde High degree of translucency and lightfinish; (Beetle, Bakelite Low impact strength; hard surface finish; outstanding electrical slight warping with Urea, Plaskon) properties when used within temperature age; poor water range of minus 70° to plus 170°F; com- resistance. plete resistance to organic solvents; dimensionally stable under moderate load- ings and exposure conditions. Used for instrument dials, electric parts, etc.

28.37.02 4-291 MACHINERY REPAIRMAN 3 & 2

amount of moisture, if placed in hot water. A (FED-L7P XXXX) designations to the correct knife blade will cut easily into thermoplastics. procuring data for the Federal Supply System. When testing a plastic by inserting it into a fire,you shouldexercisecaution,because thermoplastics will burst into sudden intense MACHINING OPERATIONS flame, and give off obnoxious gases. If you use the fire test, be sure to hold the plastic piece a Machining operationsthataMachinery considerable distance away from you. Repairmanwillperform on plastics include cutting parts from sheet or rod stock, using MAJOR GROUPS various metal cutting saws; removing stock from parts by rotating tools as in a drill press or a While it is not necessary for you to know the millingmachine;cutting moving partsby exact chemical composition of the many plastics stationary tools, as on a lathe; and finishing in existence, it will be helpful to have a general operations. idea of the composition of the plastics youare mostlikelytouse.Table4-4provides Sawing information on some groups of plastics which areofprimaryconcerntoaMachinery Severaltypes of sawsbandsaw, , Repairman. circular sawmay be used to cut blanks from Laminated plasticsare made by dipping, plasticstock.Speedsshouldbewatched spraying, or brushing flat sheets or continuous carefully.Sincealmost none of theheat rolls of paper,fabric, or wood veneer with generated will be carried away by the plastic, resins, and then pressing several layers together there is always danger that the tool will be togethard,rigid,structural material. The overheated to the point that it will burn the number of layers pressed together intoone sheet work. of laminatedplasticwill depend upon the thickness desired. The choice ofpaper, canvas, Drilling wood veneer, or glass fabric will dependupon the end use of the product. Paper-base material Indrillingplastics,backthedrillout is thin and quite brittle, breaking if bent sharply, frequently to remove the chips and cool the but canvas-base material will be difficult to tool. A liberal application of kerosene will help break.Aslayersareaddedtopaper-base keep the drill cool. To obtain a smooth, clean material, it gains in strength, but it isnever as hole, use paraffin wax on the drill; for the softer tough and strong in a laminated partas layers of plastics, a special coolant may be preferred. glass fabric or canvas. Laminated materials are widely used aboard Lathe Operations ship. For example, laminated gearsare used on internal-combustion engines, usuallyas timing or Lathe operations are substantially the same idlergears; on laundry equipment; and on for plastics as for metals, except for type of certain pumps. In comparison with metalgears, tool, and the manner in which contact is made plastic gears are quieter in operation, pickup with the work. For plastics, set the tool slightly less heat when friction is generated, andwear below center. Use cutting tools with zeroor longer. slightly negative back rake. Plastics are identified by several commercial For both thermosettings and thermoplastics, designations, trade names, and by Military and recommended cutting speeds are: 200 to 500 Federal specifications. Thereis such a large fpm with high-speed steel tools and 500 to 1500 number of types, grades, and classes of plastics fpm with carbide-tipped tools. within each major group that to rely on the recognition of a trade name only would result in Finishing Operations the wrong material being used. The appropriate Federal Supply Catalog should be used tocross Plastic must be given a finishing process to reference the Military (Ml L-P-XXXX) or Federal remove tool marks and produce a clean, smooth j 4-30 Chapter 4METALS AND PLASTICS surface.Usually,sandingandbuffingare on a wheel made of loose muslin buffs. Buffing sufficient for this purpose. compounds in commonuse aretripoli and Surfacescratchesandpitscanbe rouge; a layer of the compound is deposited satisfactorily removed by hand on sandpapering the outside of the buffing wheel. Thecompound with dry of fine grit. Wetsanding can must be renewed frequently. also be done by hand, with water and abrasive When large flat sheetsare being buffed, be paper of fine grade. If a large amount of material careful not to use too muchpressure, nor to must be removed, it will bemore advantageous hold the work too long in to use sanding wheels one position. In or disks. buffing small plastic parts, be carefulthat the After pits and scratches have beenremoved, wheel does not seize the piece and pullit out of the plastic should be buffed. Thiscan be done your grasp.

4-31.1,....; 1 CHAPTER 5

POWER SAWS AND DRILLINGMACHINES

Machine shop work is generally understood NEVER make adjustments to thesaw or to includeall cold metal work in which a relocate the stock to be sawed while thesaw is portion of the metal is removed by eitherpower in operation. driven tools or handtools. In your previous studies you have become familiar withcommon Keep hands away from the bladeas handtools. Thischapterandthefollowing far as possible while the chapters contain information on power driven, saw is in operation. or machine tools. NEVER attempt to move a large heavy The term MACHINE TOOL refers toany piece of stock to or from the saw without help. piece of power driven equipment that drills, cuts,or grinds metals and other materials. Always support protruding ends of long Through the use of attachments, some machine pieces of stock so they will not fall andcause toolswillperform two or more of these injury to either the machine or personnel. operations. Machine tools actually hold and work the material. The operator guides the NEVER use bare hands to clean thesaw mechanical movements by properly settingup cuttings from the machine. the work and by adjusting the gearingor linkage controls. In this chapter we will deal primarily Be alert for sharp burrs 011 the sawed end with power saws and drilling machines. of stock and remove such burrs witha file to prevent injury to personnel. POWER SAW SAFETY PRECAUTIONS Inspect the blade at frequent intervals and NEVER use a saw with a dull, pinched,or Before taking up the operation ofpower burned blade. saws, you must realizethe importance of observing safety precautions. Carelessness isone In all sawing jobs, the golden rule of of the prilite causes of accidents in the machine safety isSAFETYFIRST, ACCURACY shop. Moving machinery is always a potential SECOND, and SPEED. LAST. danger. When this machinery is associated with sharpcuttingtools,the hazardisgreatly increased. Some of the more important safety POWER HACKSAWS precautions are listed here: The power is found inmany Navy Onlyauthorizedandfullyqualified machine shops. It is used for cutting bar stock, personnel may operate power saws. pipe, tubing, or other metal stock. Thepower hacksaw consists of a base,a saw frame, and a Goggles or face shields must be worn at work-holding device.' Figure 5-1 isan illustration all times when operating the powersaw. of a standard power hacksaw.

5-1

1Aw MACHINERY REPAIRMAN 3& 2

close to the material to be cut. Final tightening is made by turning the visescrew until the material is held securely. An adjustable stop permits pieces of the same lengthto be cut without measuring each piece separately.A stock support stand (available for both sidesof the saw) serves to keep long stock from falling when being cut. The capacitydesignation of the power hacksaw illustrated is 4 inches X 4 inches.This means that it can handle material up to 4 inches wide and 4 inches thick.

BLADE SELECTION

The blade shown in figure 5-2 is especially designed for use with thepower hacksaw. It is made witha toughalloysteel back and high-speedsteel teeth, a combination which gives a strong blade, and at thesame time, a cutting edge suitable for high-speed sawing. These blades vary as to the pitch of theteeth 11.18X (number of teeth per inch). The correct pitch of Figure 5-1.Standard power hacksaw. teeth for a particular job is determined bythe size and the material of the sectionto be cut. Use coarse pitch teeth for wide, heavysections The base consists ofa reservoir to hold the to provide ample chip clearance. For coolant, a coolant pump, the drive thinner. motor and a sections, use a blade with a pitch that keepstwo transmission for speed selection. Some models or more teeth in contact with the work may have the feed mechanism attached to the so that the teeth do not straddle the work.Straddling base. strips the saw. In general, select blades according The saw frame consists of linkageand a to the following information: circular disk with an eccentric (offcenter)pin designedtoconvertcircularmotioninto I.Coarse (4 teeth per inch), for soft steel, reciprocating motion. The bladeisinserted cast iron, and bronze. between the two blade holders and securely 2.Regular (6 to 8 teethper inch), for attached by either hardened pinsor socket head annealed high carbon steel and high-speedsteel. \ screws. The inside blade holderis stationary while the outside blade holder is adjustable.This adjustableblade holderallowsthecorrect tension to be puton the blade to ensure that it isuheld rigidly enough to preventthe blade from wandering and causinga slanted cut. The feed control mechanism is also attachedto the saw fra' e on many models. he work holding device is normallya vise with one stationary jaw andone movable jaw. The Movable jaw is mountedover a toothed rack to permit a rapid and easy initial adjustment 11.19X Figure 5-2.Hacksaw blade. 1 ,,,5-2 Chapter 5POWER SAWS AND DRILLING MACHINES

3.Medium (10 teeth per inch), for solid pipe, the wall thickness. A hard large diameter brass stock, iron pipe, and heavy tubing. piece of stock must be cut with a slower or 4.Fine (14 teeth per inch), for thin tubing lighter feed rate than if it were soft and had a and sheet metals. small diameter. Pipe with thin walls should be cut with a relatively light feed rate to prevent COOLANT strippingtheteeth from the saw blade or collapsing the walls of the pipe. A feed rate that The use of a coolant is recommended for is too heavy or fast will often cause the saw most power hacksawing operations. (Cast iron blade to wander, producing an angled cut. can be sawed dry.) The coolant keeps the kerf Speed on hacksaws is stated in strokes per (narrow slot created by the cutting action of the minute, counting only those strokes on which blade) clear of chips so that the blade does not the blade comes in contact with the stock. bind up and start cutting crooked. The teeth of Speed is changed by a gear shift lever. There the blade are protected from overheating by the may be a chart attached to or near the saw, coolant, permitting the rate of cutting to be giving recommended speeds for cutting various increasedbeyondthe speedpossible when metals. The following speeds, however. be sawing without coolant. A soluble oil solution used: with a mixture of the oil and water, made so that no rust problems will occur, should be 1.Medium and low carbon steel, brass, and suitable for most sawing operations. The normal soft metals-136. mixture for soluble oil is 40 parts water to 1 part oil. 2.Alloy steel, annealed tool steel, and cast iron-90. FEEDS AND SPEEDS 3.Unannealedtoolsteel,andstainless Power hacksaws have one of three feed steel -60.` mechanisms:

1.Mechanicalseed, which ranges from POWER HACKSAW OPERATION 0.001 to 0.025 inch per stroke, depending upon the class and type of material being cut. A power hacksaw is relatively simple to operate. There are, however, a few checks you 2.Hydraulic feed, which normally exerts a constant pressure but is designed so that when should make to ensure goods cuts. Support hardspotsareencounteredthefeedis overhanging ends of long pieces to prevent automatically stopped or shortened to decrease sudden breaks at the cut before the work is the pressure on the saw until the hard spot has completely cutthrough. Block up irregular shapes so that, the vise holds firmly. Check the been cut through. blade to ensure that it is sharp and that it is 3.Gravity feed, where weights are provided secured at the proper tension. on the saw frame and can be shifted to give Place the workpiece in the clamping device, more or less pressure of the saw blade against adjusting it so that the cutting off mark is in line the material being cut. with the blade. Turn the vise lever to; clamp the material in place. Be sure the material is held To prevent unnecessary wear on the back firmly. side of the saw blade teeth, the saw frame and blade are automatically raised clear of the last See that the bladei,snot touching the cutting depth on the return stroke. The rate of workpiece when you start the machine. Blades feed or the pressure exerted by the blade on the are often broken when this rule is not followed. cuttingstrokeisdependentonseveral Feed the blade slowly into the work, and adjust factorsthe toughness and hardness of the the coolant nozzle so that it directs the fluid material, the size, and in the case of a hollow over the saw blade. MACHINERY REPAIRMAN 3& 2

CONTINOUS FEED CUTOFF SAW blade. With this though( inmind, one can see that all the factors that Figure 5-3 illustrates were discussed for power a type of cutoff saw hacksaw blade selectioncan be applied to this that is now being used throughoutthe Navy. saw. This saw is also equipped with There are different models of this a band saw, but the selection chart (fig. 5-3) to helpyou in making basic design and operating principlesremain the same. the proper selection. The bandscome in two different forms; readymade loops of theproper length and coils of continuous lengths BAND SELECTION AND of 100 INSTALLATION feet or more. Nothing must be doneto the pre- sized band, but the coils ofsaw bands must be The bands for the continuousfeed cutoff cut to the proper length and then butt welded. saw are nothing more than an endless hacksaw (Butt welding is covered later in thischapter.)

SAW COOLANT GUIDE VALVE ARM

f,ice

4.

CONTROL' PANEL

28.297X Figure5.3.Continuous feed cutoffsaw(DoAII Company).

5-4 1 " Chapter 5POWER SAWS AND DRILLING MACHINES

Once you have selected the saw band, install operator can raise, stop, and feed the machine it in the following manner: with the main control handle. The FEED portion of the control is divided into vernier and 1.Lift the cover on the saw head to expose rapid. The RAPID area is used to bring the saw the band wheels. band down close to the work; the VERNIER 2.Place the band on the wheels with the controls the feed pressure. Figure 5-5 shows the teeth down, or toward the deck, and pointing in vernier control knob with graduations from 0 to the direction of the band rotation. 9. By using this vernier, the operator can get the maximum cutting efficiency for the type of 3.Twist the lower part of the band and material being cut. Upon completion of the cut, insert it between the saw guides at the lower end the machine will automatically stop. To raise the of the saw guide arms. head above the workpiece for the next cut, you 4.Turn the tension handwheel two full must push the start button and place the control turns. This action applies enough tension to hold lever in the RAISE position. You may have to the band on the wheels. When the machine is hold the start button down for a second or two operating, the hydraulic system maintains the until the saw head starts to raise. proper band tension. 5.Adjust the saw guides in accordance with themanufacturer'smanual.Thedistance METAL CUTTING BANDSAWS between the two guide arms s.Iluld not be more than necessary or the blade will wander. Met alcuttingbandsawsarestandard equipment in repair ships and tenders. These 6.Selectthepropersurfacespeed machines can be used for nonprecision cutting (feet-per-minute), and adjust the V-belt for that similar to that performed by power hacksaws. speed. (See fig. 5-4.) Some types can be used for precision cutting, filing, and polishing. A has a greater CUTOFF SAW OPERATION degree of flexibility for straight cutting than a power hacksaw in that it can cut objects of any When the machine is ready for the actual reasonablesize and of regular and irregular sawing operation; you must ensure that the shapes. A bandsaw cuts faster than a power stockto be sawed is held securely in the hacksaw because the cutting action of the blade machine. The movement of the saw head is is continuou s. controlled from the control panel (fig. 5-5). The Figure5-6illustratesametalcutting bandsaw of the tiltable table type. On the type shown, work is fed either manually or by power 90 F.P.M. to the blade which runs in a fixed position. 125 F.P.M. F.P.M. 250 F.P.M. The tiltable band type saw is particularly suited to taking straight and angle cuts on large, long, or heavy pieces because the work remains in an upright position throughout the cutting operation and because there is no interference DRIVEN' pil PULLEY on long cutoffs from the free half of the band. The tiltable table type is convenient for contour cutting because the angle at which work is fed, to the blade can be changed readily. This 111 machine, usually has special attachments and accessories for precision inside or outside cutting 28.295 of contours and disks and for mitering and has Figure 5-4.Speed change pulley. special bands for filing and polishing work.

5-5 1 MACHINERY REPAIRMAN 3 & 2

0 0 0

VERNIER MAIN CONTROL CONTROL HANDLE

28.296 Figure 5.5. Control panel (DoAII saw).

HANDSAW TERMINOLOGY

As was previously mentioned, the metal cutting bandsaws installed in machine shopsin tenders and repair ships generallyare the tiltable table type which can cut, file,or polish work when appropriate bands are mountedon the band wheels. The saw bands, file bands,and polishing bands used on these machinesare called BAND TOOLS, and the machine itselfis often referred to as a BAND TOOL MACHINE. Definitionswhichwillbehelpfulin understanding band tool terminologyare given below for saws, files, and polishing bands,in that order.

Saw Bands

A saw band has the following characteristics which are illustrated in figures 5-7through 5-9.

11.21X PITCH: Designates the number of teethper Figure 5.6. Tiltable (contour)metakutting bandsaw. linear inch.

5-6 1 A.,), 0 Chapter 5POWER SAWS AND DRILLING MACHINES

Ilionsulinimillow palm RAKER SET PATTERN

PITCH WAVE SET PATTERN

Imm Imo INN INN NEN GAGE STRAIGHT SET PATTERN

29.15X 28.43X Figure 5-7.Pitch, width, and gage. Figure 5-9.Set pattern.

WIDTH: The distance across the flat face of straight. Raker set bands are generally used for the band. The width measurement is always solid cross section work. Wave set bands are used expressed in inches, or fractions of an inch. for cutting hollow materials, such as pipes and tubing, and for other work where there is a great GAGE: The thickness of the band back. This deal of variation in thickness. Straight set bands measurement is expressed in thousandths of an are not used to any great extent for metal inch. cutting work.

SET: The bend or spread given to the teeth TEMPER: Temper, or degree of hardness, of to provide clearance for the body or band back the teeth is indicated by the letters A and B, when a cut is being made. temper A being the harder. Temper A saws are used for practically all bandsaw metal cutting SIDE CLEARANCE: Thedifference work. between the dimension of the band back (gage) and the set of the teeth. Side clearance provides File Bands running room for the band back in the kerf or cut. Without side clearance,' a band will bind in A file band consists of a long steel strip upon the kerf. which is mounted a number of file segments that can be flexed around the band wheels of the SET PATTERN: There are three distinct machine and still allow the file segments to patterns to which teeth are set: raker, wave, and present a straight line at the point of work. Figure 5-10 illustrates thefile band flexing principle and shows the construction of a file band. The parts of afile band and their functions are described below:

SIDE CLEARANCE FILE SEGMENT: A section of the cutting face of a file band. The individual segments are attached to the file band with rivets.

BACK BAND: The long steel strip or loop upon which the file segments are mounted. Do not confuse this term with BAND BACK, which refers to a part of a saw band.

28.39X GATE CLIP: A steel strip at the leading end Figure 5.8.-set and side durance. of the back banda part of an adapter for

5-7 12 MACHINERY REPAIRMAN 3& 2

A- FILE SEGMENT B- BACK BAND C- TAIL GATE 0- SPACER

28.41X Figure 5-10.File band flexing principleand construction.

joining the back band ends to formthe file band loop.

TAIL GATE: A steel stripat the other end of the back band. This is theother half of the adapter for joining the back bandends to form the'file band loop.

SPACER: A smallsteelstripinserted between the file segment and thesurface of the back band. There areas many spacers as there are file segments in each file band.

Polishing Bands

Abrasive coated fabric bandsare used for grinding and polishing operationsin a band tool machine. They are mounted in thesame way as saw andfilebands. Figure5-11 shows a polishing band. Figure 5-12shows a backup supportstripbeinginstalled,beforethe 28.42X polishing band is installed. Figure 5-11.Polishing band.

5-8 Chapter 5POWER SAWS AND DRILLING MACHINES

Band Tool Guides

SAW BAND GUIDES: The upper and lower guides keep the saw band in its normal track when work pressure is applied to the saw. The lower guide is in a fixed position under the work table, and the upper guide is attached to a vertically adjustable arm above the table which permits raising or lowering the guide to suit the height of work. To obtain adequate support for 0 the band and yet not interfere with operation, place the upper guide so that it will clear the top of the workpiece by 3/8 to 1 /2 inch. Figure 5-13 shows the two principal types of saw band guides: the insert type and the roller type. Note in both types the antifriction bearing surface for the band's relatively thin back edge; this feature allows the necessary work pressure to be placed on the saw without causing serious rubbing and wear. Be sure to lubricate the bearings of the guide rollers according to the manufacturer's recommendations. FILE BAND AND POLISHING BAND 28.43X GUIDES: For band filing operations, the regular Figure 5-12.Installing a backup support stripfor sawbandguideisreplacedwithaflat, polishing band. smooth-surface metal backup support strip, as

A. INSERT B. ROLLER . TYPE TYPE

28.44X Figure 5-13.Saw band guides.

5-9 MACHINERY REPAIRMAN 3 & 2

shown in figure 5-14, which prevents sagging of Band tool machines havea multitude of the file band at the point ofwork. A similar band speeds, ranging from supportis used for a polishingband. This about 50 feet per support has a graphite-impregnated minute to about 1500 feetper minute. Most of fabric face these machines are equipped that., prevents unduewear on the back of the with a hydraulic feed which provides forthree feeding pressures: polishing band, which also is fabric. low, medium, and heavy. SELECTION OF SAW BANDS, Success in your precision sawingwith a metal cutting bandsaw dependsto a large extent on your selecting the correctsaw blade or band, running the saw band at the Saw bands are available inwidths ranging correct seed, and from 1/16 to feeding the work to thesaw at therrect rate. 1 inch; in various even-numbered Many of thenewer models of band tool pitches from 6 to 32; and inthree gages-0.025, . 0.032, and 0.035 inch. The machines have a JOB SELECTOR ilar to the gage of saw band one shown in figure 5-15, which indicates that can be used inany particular machine, the kind of saw bandyou should use for cutting any depends on the size of theband wheels. A thick saw band cannot be successfully of a large variety of materials,the speed at used on a which to operate the machine,and the power machine that has small diameterbandwheels; feed pressure to use. therefore, only oneor two gages of blades may Not all bandsaws havea job selector. You be available forsome machines. Generally, only must know something about temper A, raker set, andwave set bands are used selecting the for metal cutting work. Another correct saw bands, speeds, and feedsto operate a variable feature bandsaw successfully. Table of saw bands is that theyare furnished in 5-1 will give you readymade loops of correctlength for some machines, and for others theycome in stock form in coils of 100 feetor more from which a length can be cut and formedinto a band loop by .butt welding the endstogether in a special machine. The process of joiningthe ends and installing bands will be describedlater in this * chapter. 1

GUIDE

28A6X Figure 5-14.File band guide. 28.48X Figure 6-16.Job selector.

5-10 Chapter 5POWER SAWS AND DRILLING MACHINES

Table 5-1.Saw Pitch and Velocity for Various Metals

SAW PITCH SAW VELOCITY

MATERIAL Work Thickness Work Thickn SS Over Over .1" 2" 2" 1" 2" 2"

FERROUS METALS

Carbon Steel #1010-#1095* 14 10 6-8 175 150 125 Free Machining #X1112-#1340*. 14 8 6-8 250 200 150 Nickel Chromiuth #2115-#3415t 14 10 6-8 100 85 60 Molybdenum #4023-#4820 14 10 6-8 125 100 75 Chromium #5120-#52100 14 10 8 100 75 50 Tungsten #7620-#71360 14 10 6-8 85 60 50

Silicon Manganese #9255-#9260 14 10 6-8 100 75 50 * (SAE-numbers)

Armor Plate 14 12 6-8 100 75 50 Graphitic Steel 14 12 6-8 150 125 75 High Speed Steel 14 10 8 100 75 50 Stainless Steel 12 10 8 60 50 40 Angle Iron 14 14 10 190 175 150 Pipe 14 12 8 250 225 185 I Beams & Channels 14 14 10 250 200 175 Tubing (Thinwall) 14 14 14 250 200 200 Cast Steels 14 12 8 150 75 50 Cast Iron 12 10 8 200 185 160

NON-FERROUS METALS

Aluminum (All Types) 8 6 6-8 250 250 250 Brass 8 8 8 250 250 250 Bronze (Cast) 10 8 8 175 125 50 Bronze (Rolled) 12 10 6-8 175 125 75 Beryllium Copper 10 R 6-8 175 150 125 Copper 10 8 6-8 250 225 225 Magnesium 8 8 6-8 250 250 250 Kirksite 10 8 6-8 200 175 150 Monel Metal 10 8 6-8 . 100 75 50 Zinc 8 8 6-8 250 225 200 NON-METALS

Bakelite 10 8 6-8 250 250 250 Carbon 10 8 6-8 250 250 250 ?lastics (All Types) 12 8 8 250 250 250 Mood 8 8 6-8 250 250 250

28.297 MACHINERY REPAIRMAN 3 & 2

some of that information. Although this table does not cover all types and thicknessesof metals nor iecommended feedpressures,it provides a basis on whichyou can build from your own experience.

Tooth Pitch

Tooth pitch is the primary consideration WIDTH OF MINIMUM in SAW RAND RADII CUT selecting a saw band forany cutting job. For 1/14 1' WWWW liSe 140 cutting thin materials, the pitch shouldbe fine SQ. 3/33 1/l enough so that at least two teethare in contact lie With the work; fewer than two willcause the 1/S teeth to tend to snag and tear loose 3/14" WS' from the 1/ 4. band.Forcuttingthickmaterial,the We consideration is to not have too S/S 17/1 many teeth in on' contact with the work, because thegreater the :m number of teeth in contact, the greater the vs" 31/e feed 3/' 17 /l$ pressure must be in order to force the teeth to 1 cut into the material. 7 1/ 4

Excessive feed pressure putssevere strain on 28.47X the band and the band guides,as well as causes Figure band width selection guides. sidewise wander of the band whichresults in off-line cutting. Another pointto consider in selecting a saw band ofproper pitch for a 5-15 containssaw band radii cutting diagram particular cutting job is the compositionof the similar to the ne shown in figure 5-16. materialto hecut,itshardness,andits toughness. Table 5-1 isa saw band pitch and Band Speed velocity selection chart showing thepitch of saw band to use for cutting many commonlyused The rate at 'ch the saw band travels in metals. feet per minute frowheel to wheel is thesaw band speed for velity. Saw band velocity has Band Width and Gage considerable effecpon both the smoothness of the cut surfacand the life of the band. The higher th d velocity, the smoother thecut; The general rule is touse the widest and howev heat generated at the cutting point thickestsawbandconsistent withthe inc s as band velocity increases. Too higha requirements of the job at hand. For example,a and velocity causes overheating and failure band of maximum"width and thickness of (if bands the saw teeth. The band velocities givenin Table of different thicknessare available) is used when 5-1 arebasedon the job calls for only straight manufacturers'recom- cuts. On the other mendations,whichinturnarebased. on hand, when a layout requires radiuscuts (curved data obtained from cuts), the band selected must be saw life tests and cutting capable of experiments under various conditions.If you following the sharpest curve involved.Thus for follow the recommendations given, curved work, select the widest band you will be that will assured of the best band performanceconsistent negotiate the smallest radius required. Thesaw with maximum band life. band width selection guides,shown in figure 5-16, give the radius of the sharpest curve that Adjustment of the machine to obtainthe can be cut with a particular widthsaw band. Note that the job selector illustrated proper band velocity cannot be covered in detail in figure here because speed change isaccomplished by

5-12 ti Chapter 5 POWER SAWS AND DRILLING MACHINES differentmethodsindifferentmodels of the manufacturer's technical manual and study machines. Consult the manufacturer's technical the particular machine to learn its power feed manual for your particular machine and learn arrangement and control. how to set up the various speeds available. SIZING, SPLICING, AND Feeds INSTALLING BANDS Though manual feeding of the work to the Most contour cutting type bandsaws are saw is satisfactory for cutting metals up to 1 provided with a buttwelder-grinder combination inch thick, power feeding generally provides for joining saw bands that come in bulk stock better results and will be much safer for the coil form, and for joining broken band loops. operator.Regardlessof whether power or The butt welder is usually attached to the saw manual feed is used, it is important not to crowd machine, as shown in figure 5-17, although it the saw because the band will tend to bend and maybeportableorapedestal-mounted twist. Feed pressure must not be so light that accessory. The butt welder also makes inside the teeth slip across the material instead of cutting possible, since the saw band loop can be cutting through because this rapidly dulls the parted and rejoined after having been threaded teeth. The job selector, shown in figure 5-15, through a starting hole in the work. shows the correct feed pressures for cutting any of the materials listed on the outer ring of the The followingsections describe how to dial. In the absence of a job selector, table 5-2 determine the length of the band, how to join can be usedas a guide for selecting feed the ends in the butt welder, and how to install a pressuresforhard, medium hard, and soft band tool in the machine. metals. Band Length The power feed controls vary with different makes of bandsaws and even with different You can quickly determine the correct saw modelsof the same make; therefore,no band length for any two-wheeled handsaw by description of the physical arrangement of the measuring the distance from the center of one power feed controls will be given here. Consult wheel tothecenter of theother wheel,

Title 5-2.Feed Pressures for Hard, Medium Hard, and Soft Metal

Work thickness Material 0-1/4"1/4-1/2"1/2-1" 1-3" Over 3"

Tool Steel M M H H Cast iron M M H H Mild steel L M H H Nickel-copper. L M H H Copper-nickel ... L L H H Zinc L L M M Lead L L M M

Llight, M medium, Hheavy. 28.2011 5-13 L,,-; MACHINERY REPAIRMAN 3 2

not do this carefully, the weldmay not go completely across the ends of the band andas a result, the weld will not withstand thepressure of the cut when it is used. Oneeasy method to ensure that the ends of the band will go together perfectly is to twist one end of the banduntil the teeth are on the opposite side of the'other end. Place the band ends on top of each other, ensuring that the band back edge and theteeth are in a straight line on both sides. Carefully touch the ends of the band to the face of the grinding wheel and lightly wind until both ends have been ground completelyacross. Release the ends of the band so that theyassume their normal position. Lay the back edge of the band on a flat surface and bring the ends together. If you did the grinding correctly, the ends will meet perfectly.

2. Set the controls of the butt welderto the weld pr.s:tion and adjust accordingto the width of band to be welded. The variousmodels of butt welders that are found inmany machine shops differ in the number of controls thatmust be set and the method of setting them;Most 28A8X models have a lever that must be placed in the Figure 5-17.Butt welder-grinder unit. weld position so that the stationaryand the movable clamping jaws are separated thecorrect distance. Some models have mulitplying by 2, and adding the circumference a resistance setting of one wheel. control which is set according to the widthof band, while other models havea jaw pressure The easiest way to determine the lengthof control knob that is also set accordingto band saw band for a three-wheeled machine is to take width.Readthe manufacturer's instruction a steel tape, thread it through the machineover manual carefully before attempting welding. the wheels, and measure the distance. 3. Place the ends of the band in thejaws Before measuring between the wheelcenters, with the teeth of the band adjusttheupper away from the wheelso thatitis welder. Push the back edge of the bandfirmly approximately halfway between theupper and backtowardtheflatsurfaces behind the lower limits of vertical travel. This allowsfor clamping jaws to ensureproper alignment.. taking up any band stretchresulting from Position the ends of the band operation. so that they touch each other and are located in the center ofthe jaw opening. Some models of butt welders Band Splicing have interchangeable inserts for the clamping jawsto permit welding bands of different widths.This is Figure 5-17 shows band ends being joinedby done so that the teeth of the bandare not using a butt welder. The procedure forjoining is damaged when the jaws as follows: are clamped tight. 4. You are now ready to weld theband. 1. Grind both ends of the band until they Some welders require that the weld button are square with the band back edge. If he you do fully depressed and held until thewelding is

5-14 1 Chapter 5 POWER SAWS AND DRILLING MACHINES complete, while other welders required only that the smallest wheel on the bandsaw by bringing the button be fully depressed and then quickly your hands together. Move your hands up and released. There will be a shower of sparks from down in opposite directions and observe the the welding action. Be sure that you are wearing welded area as it rolls around the radius that you either safety glasses or a face shield before formed. welding and then stand back from the welder when you push the button. Installing Bands 5. When the welding is complete, release the jaw clamps and remove the band from the Insert saw band or tool guides of correct size welder. Inspect the band to be sure it is straight for the band you are going to install. Adjust the and welded completely across. Do not bend or upper band wheel for a height that will allow the flex the band at this time to test the weld. The band to be looped easily around the wheels. welding process has made the weld and the area Then place one end of the loop over the upper nearithardand brittle and breakage will band wheel and the other end of the loop probably occur. around the lower band wheel, being sure that the teeth are pointing downward on the cutting 6. Place the lever that controls movement side of the band loop and that the band is of the jaws in the anneal position. This should properly located in the guides. Place a slight separate the jaws again. Set the control that tension on the band by turning the upper wheel regulates the anneal temperature to the setting takeup hand wheel and revolve the upper band for the width of the band. wheel by hand until the band has found its 7. Place the band in the clamping jaws with tracking position. If the band does not track on the teeth toward the welder and the welder the center of the crowns of the wheels, use the section in the center of the jaw opening. Close upper wheel tilt control to correct the band the jaws. track as illustrated in figure 5-18. 8. The band is ready to be annealed. Push When the band is tracking properly, adjust the anneal button and then quickly release the band guide rollers or inserts so that you have repeatedly until the welded area becomes a dull a total clearance of 0.001 to 0.002 inch between cherry red. (Do NOT push and hold the anneal button. Thiswill overheat and damage the band.) After the proper temperature is reached, push the anneal button and release it with increasingly longer intervals between the push cycle to allow the band to cool slowly. 9. The metal buildup resulting from the weld must be ground off. Using the attached grinding wheel, remove the weld buildup from both sides and the back until the band fits snugly into the correct slot on the saw band thickness gage mounted on the welder. You must do thisgrindingcarefully to prevent looseness or binding between the saw guides and the band. Be careful not to grind on the teeth of the band. 10. Repeat the procedure for annealing in step 8 after grinding the blade. 11. The welding process is complete. To test your weld, hold the band with both hands and MAW form a radius in the band slightly smaller than Figure 5-18.Upper wheel tilt adjustment.

5-15 1. MACHINERY REPAIRMAN3 & 2 the sides of the band back and the guide rollers pressure. Do not make a sudden change or inserts, and a slight contactbetween the back in feed pressure because such a changemay cause the edge of the band back andthe backup bearings band to break. of the guides. When bandguide clearance has been set, increase the bandtension. The amount of tension to be put Be sure the saw band andguides are on the band depends upon properly lubricated. the width and gage of theband. A narrow, thin band will not stand as much tension as a wider Usk lubricants and cutting or thicker band. Too muchtension will cause a coolants band to break; insufficient recommended by the manufacturerof your tension will cause the machine. / saw to run off the cutting line. Thebest way to obtain the proper tension is to start with a Straight Cuts with Power Feed moderate tension; if thesaw tends to run off the line when cutting, increasethe tension slighty. 1.Change band guidesas necessary. Select and install theproper band for the job and SAWING OPERATIONS ,adjust the band guides. As previously 2.Place the workpieceon the table of the mentioned, the types of machine and center the work in sawing operations possiblewith L. band tool the work jaw. machine are straight, angulrcontour, inside, 3. Loop the feed chainaround the work and disk cutting. Theprocedures for each of jaw, the chain rollerguides, and the left-right these cutting operationsare described it the guide sprocket,as shown in figure 5-19. following paragraphs; butfirst, let us consider the 4. Determine theproper band speed and set generalrulesapplicabletoallsawing operations. the machine speed accordingly. 5.Start the machine and feedthe work to General Rules the saw in themanner described in the general rules of operation given inthe preceding section. Use the left-right controlfor guiding the work Check the level of theworktable and along the layout line. adjust the table, ifnecessary, to suit the angle of the cut. Angular Cutting Use the proper blade andspeed for each Angular or bevel cutson flat pieces are made cutting operation. Thisensures not only the in the same way fastest and most accuratework but also longer as straight cuts except that the saw life. table is tilted to the desiredangle of the cutas shown in figure 5-20.

Always be sure the band guideinserts are Contour Cutting the correct size for thewidth of the band installed and that theyare properly adjusted. Contour cutting, that is, followingstraight, angle, and curved layoutlines, can be done Before starting the machine,adjust the offhand or with the height of theupper band guide so that it will power feed. The left-right clear the work from 3/8 chain control, shown infigure 5-19, is used for to 1/2 inch. The closer guiding the work along the guideisto the work, the greaterthe the layout line when accuracy. power feed is used. A fingertip controlfor actuating the sprocket is locatedat the edge of the worktable. If thereare square corners in the When starting a cut, feedthe work to the layout, drill a hole adjacent saw gradually. After thesaw has started the kerf, to each corner; this increase the feed slowly will permit theuse of a wider band, greater feed to the recommended pressure, and faster cutting.

5-16 Chapter 5POWER SAWSAND DRILLING MACHINES

ns

WORKJAW

LEFTT. I .GU CK ,

HYDRAULIC FE EAR

AO' LEFT-RIGHT CONTROL K

28.60X Figure 5-1 9. Work jaw and feed chain adjustment.

Figure 5-21 shows the placement of corner holes on a contour cutting layout.

Inside Cutting To make an inside cut, drill a starting hole slightly larger in diameter than the width of the band you are going to use. Remove the band from the machine. Shear the band; slip one end through the hole, and then splice the band. When the band has been spliced and reinstalled, the machine is ready for making the inside cut as illustrated in figure 5-22.

Disk Cutting

Disk cutting can be done either offhand by laying out thecircle on the workpiece and 28.60X following the 'layout circle or by using a disk Figure 5-20.Angular cutting. cutting attachment which automatically guides

5-17 .1 MACHINERY REPAIRMAN 3 & 2

28.54X 28.52X Figure 5.23. Disk -cutting attachment. Figure 5-21.Sharp radii cutting eliminated by drilling corner holes. guidepost. Position the workpiece (fig. 5-23)so that the saw teeth are tangent to the scribed the'-work-Jthat a perfect circle is cut. Figure circle.Adjust the pivot point radially and 5-23 shows a disk cutting attachment inuse. The vertically so that it seats in the center-punch device consists of a radius arm,a movable pivot mark; then clamp the pivot point securely. Then point, andoa suitable clamp for attaching the rotate the work around the pivot point to cut assembly to the saw guidepost. To cuta disk. the disk. using this device, lay out the circle and puncha centcr point. Clamp the radius arm to the Filing and Polishing

In filing and polish finishing, the work is manually fed and guided to the band. Proper installation of the guides and backup support strips is very important if good resultsare to be obtained. A guide similar to theone shown infigure 5-24isvery helpful when working to close tolerances. Besure to wear goggles or an eye protection shield when filing and polishing, and above all, be careftil ofyour fingers.For proper band speeds and work pressures, consult the manufacturer's technical manual for the machineyou are using.

DRILLING MACHINES AND DRILLS

Although drilling machines or drillpresses are commonly used by untrained personnel,you 28.53X cannot assume that operating these machines Figure 5-22.Inside cutting. proficiently is simply a matter of inserting the

1313 5-18 fI Chapter 5POWER SAWS AND DRILLING MACHINES

Check the twist drill to ensure that it is properly ground and is not damaged or bent. Make sure that the cutting tool is held tightly in the drill press spindle.

Use the correct feeds and speeds. When feeding by hand, take care to prevent the drill from digging in and taking an uncontrolled depth of cut. Do NOT remove chips by hand. Use a brush.

TYPES OF MACHINES The two types of drilling machines or drill 28.55X presses common to the Navy machine shop are Figure 5-24.Polish finishing. the upright drill press and the radial drill press. Thesemachineshavesimilaroperational characteristics but differ in application in that proper size drill and starting the machine. As a the radialdrillprovides for positioning the Machinery Repairman, you will be required to drilling head rather than the workpiece. perform drilling operations with a great degree of accuracy. It is therefore necessary for you to Upright drill presses discussed in this section be well acquainted with the types of machines will be the general purpose, the heavy duty, and and the methods and techniques of operation of the sensitive drill presses. One or more of these drill presses and drills found in Navy machine types will be found on practically all ships. They shops. are clasaified primarily by the size of drill that can be used, and by the size of the work that DRILLING MACHINE can be set up. SAFETY PRECAUTIONS The GENERAL PURPOSE DRILL PRESS Because of the widespread use of the drill (ROUND COLUMN), shown in figure 5-25, is press by such a diverse group of people with perhaps the most common upright type of different training and experience backgrounds, machine andhasflexibility!noperational some unsafe operating practices have become characteristics. As you can see in the illustration rather routine inspite of the possibility of the basic components of this machine are: serious injury. The basic safety precautions for the use of a drill press are listed below: The BASE has a machined surface with T-slots for heavy or bulky work. Always wear safety glasses or a face shield when operating a drill press. The COLUMN supports the worktable, the drive mechanism and spindle head. Keep loose clothing clear of rotating parts. The WORKTABLE and ARM canbe swiveled around the column and can be moved NEVER attempt to hold a piece being up or down to adjust for height. In addition, the drilledin your hand. Use a vise, hold-down worktable may be rotated 360° about its own bolts or other suitable clamping device. center.

5-19 130 MACHINERY REPAIRMAN 3 & 2

holes. They differ from the generalpurpose drill presses in that the worktable moves vertically only. The worktable is firmly gibbed to vertical ways or tracks on the front of the column and is further supported by a heavy adjustingscrew from the base to the bottom of the table. Asthe tablecan be moved verticallyonly,itis necessary to position the work for each hole. The SENSITIVE DRILL PRESS shown in figure 5-26 is used for drilling small holes in work under conditions which make itnecessary for the operator to "feel" what the cutting tool is doing. The tool is fed into the work bya very simple devicea lever, a pinion and shaft, anda rack which engages the pinion. These drillsare nearly always belt-driven because the vibration causedbygearingwouldbeundesirable. Sensitive drill presses are used in drilling holes lessthanone-half inchindiameter. The

0EPTN STOP 11.101

SPINDLE

FEED LEVEN

11.9X Figure 5.25. General purpose drillpress. TAILE

TAILS CLAMP INDEX PIN The SPINDLE HEAD guides and supports the spindle and can be adjusted verticallyto provide maximum supportnear the spindle almo socket.

The SPINDLE is a splined shaft witha Morse taper socket for holding the drill. The spline permits vertical movement of the spindle while it is rotating. 'Amu

The DRIVE MECHANISM includesthe motor,speedandfeedchangegears,and mechanical controls.

HEAVY DUTY DRILL PRESSES (BOX, 11.10X COLUMNS) are normally used in drilling large Figure 5-26.Sensitive drill press. 1V1 Chapter 5POWER SAWS AND DRILLING MACHINES high-speed range of these machines and the tool at a selected rate per revolution of the holding devices used, make them unsuitable for spindle; (4) depth setting devices which permit heiry work. the operator to preset the required depth of The RADIAL DRILL PRESS, shown in penetration of the cutting tool; and (5) coolant figure 5-27, has a spindle head on an arm that systems to provide lubrication and coolant to can be rotatedaxially on the column. The the cutting tool. spindle head may be traversed horizontally along the ways of the arm, and the arm may be moved On other machines the control levers may be verticallyinrelationtothe column. This placed in different positions; however, they., machine is especially useful when the workpiece serve the same purposes as those shown. In using ' is bulky or heavy or when many holescan be the locking clamps to lock or "dog down" the drilled with one setup. The arm and spindleare table or head of a drill after it is positioned over dedgned so that the drill can be positioned the work, make sure that the 'locking action does easily over the layout of the workpiece. not cause the drill or work to move slightly out of position. Some operational features that are common to most drilling machines are:(1) high- and low-speedrangesprovidedfromeithera TWIST DRILL two-speed drive motor or a low-speed drive gear; (2) a reversing mechanism for changing the direction of rotation of the spindle by either a The twist drill is the tool generally used for reversible motor or a reversing gear in the drive drilling holes in metal. This drill is formed either gear train; (3) automatic feed mechanisms which by forging and twisting grooves ina flat strip of are driven from the spindle and feed the cutting steel or by milling a cylindrical piece of steel.

RM ELEVATING SCREW COLUMN AIM SPINDLE HEAD

'SPEED CHANGE LEVER CHANGE LET_

SPINDLE SOCKET COMBINATION ARM ELEVATIN AND LOCKING LEVER HORIZO TAL TRAVERSE HANDWHEEL

COLUMN LOCKING LEVER

11.11X Figure 5.27. Radial drill press.

5-21 41 MACHINERY REPAIRMAN 3 & 2

In figure 5-28 you see the principal parts of drill. The point of thedrill should not be a twist drill: the BODY, the SHANK, and the confused with the dead center. The point is the POINT. The portion of the LAND behind the entire cone-shaped surface at the cutting end of MARGINisrelievedtoprovideBODY the drill. The WEB of the drill is the metal CLEARANCE. The body clearance assists in column which separates the flutes: Itruns the reducing friction during drilling. The LIP is the entire length of the body between the flutes and cuttilig edge, and on the CONE of the drill isthe graduallyincreasesinthickness toward the areacalledtheLIP CLEARANCE. DEAD shank, giving additional rigidity to the drill. CENTER is the sharp edge located at the tipend of the drill. It is formed by the intersection of The TANG is found only on tapered shank the cone- shaped surfaces of the point and should tools. It fits into a slot in the socketor spindle always be in the exact center of the axis ofthe of the drill press and bearsa portion of the driving strain. Its principalpurpose is to make it easy to remove the drill from the socket with DEAD CENTER the aid of a drill drift. (NEVERuse a file or LIP OR screwdriver to do this job.) CUTTING EDGE \ lib. POINT The SHANK is the part of the drill which fits into the socket, spindle, MARGIN or chuck of the drill FLUTE press. The types of shanks that are most often LAND found in Navy machine shopsare the Morse taper shank, shown in figures 5-28 and 5-29A 111 BODY BODY CLEARANCE

AXIS OF DRILL

SHANK

A B C

TANG 28.318 Figure 5-29.Twist drills: A. Three-flutedcore drill; B. Carbide tippeddrill with two helicalflutes; C. 44.20111) X Carbide tipped die drill with two flutes parallel to Figure 5-28.The parts of a twist drill. drill axis.

5-22 4 Chapter 5POWER SAWS AND DRILLING MACHINES

and the straight shank, shown in figures 5-29B number sizes run from No. 80 to No. 1 (0.0135 and 5-29C. to 0.228 inch).

Twist drills are made from several different Before putting a drill away, wipe it clean and materials. Drills made from high-carbon steel are then give it a light coating of oil. Do not leave available;however,thelowcuttingspeed drills in a place where they may be droppedor requiredtokeepthistypeofdrillfrom where ,heavy objects may fall on them. Do not becoming permanentlydulllimitstheir use place drills where they will rub against each considerably. Most of the twist drills thatyou other. will use are made from high-speed steel and will have two flutes (fig. 5-28). DRILLING OPERATIONS Core drills (fig. 5-29A) have three ormore flutesandareusedtoenlargeacastor Using the drill press is one of the first skills previously drilledhole. Core drills are more you willlearnasa Machinery Repairman. efficientand more accurate when used to Although a drill press is relatively simpler to enlarge a hole than the standard two-fluted drill. operate and understand than other machine Core drills are made from high-speed steel. tools in the shop, the requirements foraccuracy and efficiency in its use are no less strict. To A carbide-tipped drill (fig. 5-29B), which is achieve skill in drilling operatiors, you must similar in appearance to a standard two-fluted have a knowledge of feeds and speeds, how the drill with carbide inserts mounted along the lip work is held, and how to ensure accuracy. or cutting edge, is used for drilling nonferrous metals, cast iron, and cast steel at high speeds. Speeds, Feeds, and Coolants These drills are not designed for drilling steel and alloy metals. The cutting speed of a drill is expressed in feet per minute (fpm). This speed is computed A carbide-tipped die drill, or spade drill as it by multiplying the circumference of the drill (in is often called (fig. 5 -29C), has two flutes that inches) by the revolutions per minute (rpm) of run parallel to the axis of the drill as opposed to the drill. The result is then divided by 12. For the helical flutes of the standard two-fluted drill. example,a1/2-inchdrill,whichhasa This drill can be used to drill holes in hardened circumference of approximately1 1/2 inches, steel. turned at 100 rpm has a surface speed of 150 inches per minute. To obtain fpm, divide this A standardtwo-fluteddrill made from figure by 12 which results in a cutting speed of cobalt high-speed steelis superior in cutting approximately 12 1/2 feet per minute. efficiencyandwearresistancethanthe high-speed steel drill and is used at a cutting The correct cutting speed for a job depends speed between the speed recommended fora on many variable factors. The machinability of a high-speed steel drill and a carbide-tipped drill. metal, any heat treatment processes suchas hardening, tempering, or normalizing, the type A solid carbide drill with two helical flutes is of drill used, the type and size of the drilling also available and can be used to drill holes in machine, the rigidity of the setup, the finish and hard and abrasive metal where no sudden impact accuracy required, and whether or not a cutting will be applied to the drill. fluid is used are the main factors thatyou must consider when selecting a cutting speed for Drill sizes are indicated in three ways: by drilling.Thefollowingcuttingspeedsare measurement, letter, and number. The nominal recommended for using high-speed steel twist measurements range, from 1/16 to 4 inches or drills.Carbon steeldrills should be run at larger, in1/64-inch steps. The letter sizes run one-f these speeds, while carbide may be run from "A" to "Z" (0.234 to 0.413 inch). The at two to three times these speeds. As you gain

5.21 43 MACHINERY REPAIRMAN 3 & 2 experience in using twist drills, you will be able The feed of a drill is the rate of penetration to vary the speeds to suit the job you are doing. into the work for each revolution. Feed is expressedinthousandths of aninchper Low carbon steel 80-110 fpm revolution. In general, the larger the drill, the heavier the feed that may be used. Always Medium carbon steel 70-80 fpm decrease feed pressure as the drill breaks through the bottom of the work to prevent drill breakage High carbon steel 50-60 fpm and rough edges. The rate of feed depends on the size of the drill, the material being drilled, Alloy-steel 50-70 fpm and the rigidity of the setup. Corrosion-resistant Usethefollowingfeedrates,givenin steel (stainless) 30-40 fpm thousandths of an inch per revolution (ipr), as a general guide until the experience that yoir will Brass 200-300 fpm gain allows you to determine the most efficient feed rate for each different job. Bronze 200-300 fpm Drill Diameter IPR Monel 40-50 fpm No. 80 to 1/8 inch 0.001-0.002 Aluminum 200-300 fpm 1/8 inch to 1/4 inch 0.002-0.004

Cast iron ,70-150 fpm 1/4 inch to 1/2 inch 0.004-0.007 The speed of the drill press is given inrpm. Tables giving the proper rpm at which to run a 1/2 inch to 1 inch 0.007-0.015 drill press for a particular metal are usually available in the machine shop, or theymay be Greater than 1 inch 0.015-0.025 found in mrninists' handbooks. A formulamay be used to determine the rpm required to givea The lower feed rate given for each range of drill specific rate of speed in fpm for a specific size sizes should be used for the harder materials drill. For example, if you wish to drilla hole 1 such as tool steel, corrosion-resistant steel and inch in diameter at the speed of 50 fpm,you alloy steel, while the higher feed rate should be would compute the rpm as follows: used for brass, bronze, aluminum, and other soft metals. fpm X 12 rpm It is usually necessary to use a cutting oilor ir X D coolant for drilling carbon steel, alloy steel, 50X 12 corrosion-resistant steel and certain nonferrous 3.1416 X metals such as Monel. Aluminum, brass, cast iron, bronze and similarly soft metalsmay be drilled dry unless a high drilling speed and feed 600 are used. A mineral-lard oil should be used for 3.116 the exceptionally hard metals; however, soluble oil can be used for most drilling operations. = 190 where Holding the Work fpm= required speed in feet per minute Before drilling, be sure your work is well = 3 . 1 4 1 6 clamped down. On a sensitive drill press you will 12SI constant probably have to use a drill vise and center the D= diameter of drill in inches work by hand. Because the work doneon this

5-24 14 4 Chapter .5 POWER SAWS AND DRILLINGMACHINES

drill press is comparatively light, theweight of the vise is sufficient to hold the workin place. ANOLA PLATO The larger drill presses have slotted tablesto which work of considerable weight MORK can be DRILL PPM bolted or clamped. T-bolts, which fit intothe TAUB T-slots on the table, are used for securingthe work. Various types of clamping straps,shown in figure 5-30, also can be used. (Clampingstraps CLAMPS are also identified as clamps or dogs.) The PACKING BLOCK CLAMP U-strap is the most convenient formany setups PARALLAL /LOCK because it has a larger range of adjustment. V- BLOCK It is often necessary touse tools such as steel parallels,V-blocks,andangleplatesfor supporting and holding the work. Steel parallels are used to elevate the work above the tableso that you can better see the progress of the drill. V-blocks are used for supporting round stock, and angle plates are used to suppert work where 11.15X a hole is to be drilled at an angle to another Figure 5.31. Work mounted on table. surface. Some examples of setupsare shown in figure 5-31. proper techniques to prevent the drill from Drilling Hints startingoffcenteror from moving out of alignment during the cut. Hereare some hints To ensure accuracy in drilling, positionthe thatwillaid you in correctlystarting and work accurately under the drill, anduse the completing a drilling job.

1. Before setting up the machine, wipeall foreign matter from the spindle and table ofthe machine. A chip in the spindle socket willcause the drill to have a wobbling effectwhich tends to make the hole larger than the drill. Foreign matter on the work holding device underthe workpiece tiltsit in relation to the spindle, causing the hole to be out of alignment. 2. Center punch the work at the pointto FLAT STRAPS bedrilled.Positionthecenter-punched workpiece under the drill;use a dead center insertedin the spindle socket to align the center-punch mark on the workpiece directly under the axis of the spindle. 3. Bring the spindle with theinserted center down to the center-punch mark andhold it in place lightly while fastening lockingclamps or dogs. This will prevent slight movement of the workpiece, table,or both when they are 11STRAP GOOSENECK STRAP clamped in position. 4. Insert a center drill (fig. 5.32) inthe spindle and make a center hole to aid instarting 11.15X the drill. This is not necessaryon small drills on Figure 6.30. Common typos of clampingstraps. which the dead center of the drill is smallerthan

5-25 145 MACHINERY REPAIRMAN 3 & 2

inch times the drill diameter plus 0.003 inch. For example, a 1/2-inch drill can be expected to result in a hole approximately 0.505 in diameter ([0.004 X 0.5001+ 0.003).This amount can 28.57X vary up or down depending on the condition of Figure 5-32.Combined drill and countersink (center the drilling machine and the twist drill. drill). Correcting Offcenter Starts the center-punch mark, but on large drills it will A drill may startoffcenter because of prevent the drill from "walking" away from the improper center drilling, careless starting of the center-punch mark. This operation is especially drill, improper grinding of the drill point, or important in drilling holes on curved surfaces. hardspotsinthemetal. To correctthis 5. Using a drill smaller than the required condition, take a half-round and cut a size to make a pilot hole will increase accuracy groove on the side of the hole toward which the by eliminating the need of the dead center of center is to be drawn. (See fig. 5-33.) The depth the finishing drill to do any cutting, decreasing of this groove depends upon the eccentricity the pressure required for feeding the finishing (deviation from center) of the partially drilled drill and decreasing the width of cut taken by hole with the hole to be drilled. When the each drill.Indrilling holes over 1 inch in groove is drilled out, lift the drill from the work diameter, you may need to use more than one and check the hole for concentricity with the size of pilot drill to increase the size of the hole layout line. Repeat the operation until the edge by steps until the finished size is reached. of the hole and the layout line are concentric. 6. If the outer corners of the drill (margin) When the drill begins to cut its full diameter, the appear to be wearing too fast or have a burnt prick-punch marks on the layout should be look, the drill is going too fast. evenly cut at the centers. 7. If the cutting edges (lip) chip during drilling, too much lip clearance has been ground When usingthis method tocorrect an into the drill, or too heavy a feed rate is being offcenter condition, you must be very careful used. that the cutting edge or lip of the drill does not 8. A very small drill will break easily if the grab in the chisel groove. Generally, you should drill is not going fast enough. use very light feeds until the new center point is 9. When a hole being drilled is more than established. (Heavy feeds cause a sudden bite in three or four times the drill diameter in depth, the groove which 'may result in the work being the drill should be backed out frequent)to clear the chips from the flutes. 10. Ifthedrill becomes hot quickly,is difficult to feed, squeals when being fed and produces a roughfinish in the hole, it has become dull and requires resharpening. 11. 1f the drill has cutting edges of different angles or ur.equal length, the drill will cut with only one lipand will wobble in operation, resulting in an excessively oversized hole. 12. If the drill will not penetrate the work, insufficient or no Up clearance has been ground into the drill. 13. The majority of drilled holes will he oversized regardless of the care taken to ensure a 11.17X goodsetup. Generally, you can expect. the Nur. 5-33.Usha halt -round chisel to golds a drill to oversize to average an amount equal to 0.CC4 %t. lorroot ante.

5.2(1

W4117L'tittis .&4141 Chapter 5POWER SAWS AND DRILLING MACHINES' pulled out of the holding device,or the drill being broken.)

Counterboring, Countersinking, and Spotfacing

28.59X A is a drilling tool used inthe Figure &M.. drill press to enlarge portions ofpreviously drilled holes to allow the heads offastening devices to be flush withor below the surface of difference in countersinking and counterboring the workpiece. The parts ofa counterbore that is that a countersink makesan angular sided distinguish it from a regular drillare a pilot, recess, while the counterbore forms straight whichaligns the toolinthehole to be sides. The angular point of the countersinkacts counterbored, and thecutting edge of the as a guide to center the tool in the hole being counterbore, which is flat so thata flat surface is countersunk. Figure 5.35 shows twocommon left at the bottom of the cut, enabling fastening types of countersinks. devices to seat flat against the bottom ofthe counterbored hole. Figure5-34 Spotfacing is an operation that cleansup the showstwotypesof surface around a holeso that a fastening device counterbores and an example ofa counterbored can be seated flat on the surface. This operation hole.The basicdifferencebetweenthe is commonly requiredon rough surfaces that counterboresillustratedisthatone has a havenot removable pilot and the other beenmachinedandonthe does not. A circumference of concave orconvex workpieces. counterbore with provisions fora removable pilot can be used in counterboring Figure 5-36 shows an example of spotfacingand a range of the application of spotfacing in using fastening hole sizes by simply using theappropriate size devices. pilot. The use of the Thisoperationiscommonly counterbore with a fixed accomplished by using a counterbore. pilot is limited to holes of thesame dimensions as the pilot. Reaming Countersinks are used for seating flathead screwsflushwiththe surface. The basic In addition to drilling holes, the drillpress may be used for reaming. For example, when specifications call for close tolerances, the hole must be drilledslightly undersize and then reamed to the exact dimension. Reaming is also done to remove burrs ina drilled hole or to

X2 HEX, HEAD PI CAP SCREW TANG TAPER SHAN PILOT SETSCREW

COUNTERSORE

A B

28.58 28:60 Figure 5.34. -Ono typo of countottoro. Figure 536.Examples of spotf going.

5.27 14 7 MACHINERY REPAIRMAN 3 & 2 enlargeapreviouslyusedholefornew 3.Adjustthe machinefor the proper applications. spindle speed. (Reamers should turn at about Machine reamers have tapered shanks so that one-half the speed of the twist drill.) they fit the drilling machine spindle. Be sure not to confuse them with hand reamers, which have 4.Use a cutting oilto ream. Use just straight shanks. Hand reamers will be ruined if enough pressure to keep the reamer feeding into used in a machine. the work; excessive feed may cause the reamer There are many types of reamers, but the to dig in and break. ones used most extensively are the straight 5. The starting end of a reamer is slightly fluted, the taper, and the expansion types. They tapered; always run it all the way through the are illustrated in figure 5-37. hole. NEVER RUN A REAMER BACKWARD because the edges are likely to break. The STRAIGHT FLUTED REAMER is made to remove small portions of metal and to Tapping cut along the edges to bring a hole to close tolerance. Each tooth has a rake angle which is Specialattachments thatpermit cutting comparable to that on a lathe tool. internal screw threads with a tap driven by the drilling machine spindle can save consideraLle The TAPER PIN REAMER has a tapered time when a number of identically sized holes body and is used to smooth and true tapered must be threaded. The attachment is equipped holes and recesses. The taper pin reamer is withareversingdevicethat automatically tapered at 1/4 inch per foot. changes the direction of rotation of the tap when either the tap strikes the bottom of the The EXPANSION REAMER is especially hole or a slight upward pressure is applied to the useful, inenlarging reamed holes by a few spindle down-feed lever. The reversing action thousandths of an inch. It has a threaded plug in takes place rapidly, permitting accurate control the lower end which expands the reamer to over the depth of the threads being cut. A various sizes. spiral -fluted tap should be used to tap a through The steps outlined below should be followed hole while a standard straight-fluted plug tap can in reaming: be used in a blind hole. A good cutting oi1.4 shouldalways be usedintapping with a 1.Drill the hole about 1/64 inch less than machine. the reamer size. 2.Substitute the reamer in the drill press without removing the work or changing the DRILLING ANGULAR HOLES position of the work. An angular hole is a hole having a series of straight sides of equal length. A square (4-sided), a hexagon (6-sided), a pentagon (5-sided), and an octagon (8-sided) are examples of angular STRAIGHT FLUTED PEAK holes. An angular hole that goes as the way through a part can be made easily by using a broach; however, a blind hole, one in which the TAPER REAMER angular hole does not go all the way through the part, cannot be made with a broach. There are two methods available to you for machining a EXPANSION REAMER blind angular hole. One method, the shaper, will be covered later in Chapter 12. The second method, drilling the angular hole in a drill press 6.10X or on a lathe, will be briefly described in the Figure 5-37.Reamers. following paragraphs.

5-28 148 Chapter 5POWER SAWS AND DRILLINGMACHINES

EQUIPMENT isincludedinthefollowing paragraphs. A complete description of the equipment The equipment required to drill and, its angular use is available from the manufacturerwhen the holes is specialized and is designed to accomplish equipment is ordered. only this particular operation. The machining process, known as the WATTS METHOD,was Chuck developed by the Watts Bros. Tool Works, Incorporated and the required equipment is The chuck (fig. 5-38A) used in drillingan- patented and manufactured exclusively bythat gular holes is of an unusual design in that while company. A brief description of the equipment it holds the drill in a position parallelto the

ga

-..* irs ) \ S

\ A". 0

i

FLOATING CHUCK GUIDEHOLDER III SQUAREDRILL

;,11\it al

- .... :.

II 11 11:) :1 1 , HEXAGON DRILL GUIDE PLATES SLIP BUSHINGS

28.319 Figure 5-38. Equipment for drilling angular holes. A. Chuck; B. Guide plate; C. Guide holder;D. SlIp bushing; E. Angular drill

5-29 1.19 MACHINERY REPAIRMAN 3 & 2

spindle of the lathe or drill press and prevents it Angular Drill from revolving, it allows the drill to freely so that the flutes can follow the sides of the The angular drills (fig. 5-38E) are straight angular hole in the guide. plate. The chuck is fluted and have one less flute or cutting lip than available with a Morse taper shank to fit most the number of sides in the angular hole it is lathesanddrillpresses.Thereareseveral designed to drill. The drills have straight shanks differentsizesof chucks,eachcapable of with flats machined on them to permit securing accepting drills for a given range of hole sizes. them in the floating chuck with setscrews. The cutting action of the drill is made by the cutting Guide Plates lips Or edges on the front of the drill.

The guide plate (fig. 5-38B) is the device OPERATION that causes the drill to make an angular hole. The free-floating action of the chuck allows the The procedure for drilling an angular hole is drill to randomly follow the straight sides and similar to drilling a normal hole, differing only corners of the guide plate as it is fed into the in the preliminary steps required in setting the work. Attach the guide plate to a guide holder job up. The feeds and speeds for drilling angular when using a lathe and directly to the work holes should be slower than those recommended when using a drill press. A separate guide plate is for drilling a round hole the same size. Obtain required for each different shape and size hole. specific recommendations concerning feeds and speeds from the information provided by the Guide Holder manufacturer. Use a coolant to keep the drill cooland helpflush away thechips. The The guide holder (fig. 5-38C), as previously following procedures apply when the work is stated, holds the guide plate and is placed over being done on a lathe. See figure 5-39 foran the outside diameter of the work and locked in example of a lathe setup. place with a setscrew. The guide holder is used when the work is being done in a lathe and is 1.Place the work to be drilled in the lathe not required for drill press operations. chuck. The work must havea cylindrical outside diameter andtheintended location of the Slip Bushings angular hole must be in the center of the work. 2.Place the guide. holder over the outside Prior to actually drilling with the angular diameter of the work and tighten the setscrew. . hole drill, you must drill a normal round hole in If the bore in the back of the guide holder is the center of the location where the angular hole larger than the diameter of the work, makea will be located. This pilot hole reduces the sleeve to adapt the two together. If the part to pressure that would otherwise be required to be drilled is short, place it in the guide holder feed the angular drill and ensures that the and place the guide holder in the chuck. angular drill will accurately follow the guide 3.Drill the pilot hole at this time. The size plate. In a lathe, you need only to drill a hole of the pilot hole should be slightly smaller than using the tailstock since it and the chuck will the distance across the flats of the angular hole. automatically center the pilot hole. In a drill Themai .facturer makesspecific press, a method must be devised to assist, you in recommendations on pilot hole sizes. this alignment of the pilot hole. A slip bushing 4.AttaCh the guide plate to the guide will accomplish the job quickly and accurately. holder. The slip bushing (fig. 5-38D) fits into the guide 5.Mount the floating chuck in the lathe plate and has a center hole which is the correct tailstock spindle and place the drill in the chuck. size for the pilot hole of the particular size Tighten the setscrews to hold the drill securely. angular hole being drilled. Then, position the 6. You are now ready to drill the angular correct drill so that it enters the hole in the slip hole. Do not force the drill into the work too bushing and drill the pilot hole. rapidly, and use plenty of coolant.

5-30 Chapter SPOWER SAWS AND DRILLINGMACHINES

28.320 Figure 5-39.Lathe setup for drillingan angular hole.

The setup for drilling an angular holeusing a Figure 5-40 shows a disintegrator removinga drill press differs in. that instead of usinga guide broken stud. holder, clamp the guide plate directlyto the work and drill the pilot hole by usinga slip Obtain the specific operating procedures for bushing placed in the guide plateto ensure themetaldisintegrator from the reference alignment. Once you have pvitioned thework materialfurnishedbythemanufacturer; under the drill press spindle and drilled thepilot however, there are several stepsinvolved in hole, do not move the setdpany movement setting up for a disintegrating job thatare will result in misalignment of the workand the common to most of the models of disintegrators angular drill. found aboard Navy ships. Setting up the part to be disintegrated is the first step that must be 'done. Some disintegrator METAL DISINTEGRA;'ORS modelshaveabuilt-intablewiththe disintegrating head mounted aboveitin a There are occasions when a broken tapor a fashion similar to a drillpress. On a machine woken hardened stud cannot be removedby the such as this, you need onlyto bolt the part isual removal methods previously covered.To securely to the table, ensuring thatthe part accomplish removal without damaging thepart, makes good contact so that isea an electrical ground metaldisintegrator.Thismachine is provided. Align the tapor stud to be removed lisintegrates a hole through the brokentap or square with the table so' that the electrode will tud bythe use of an electrically charged followthecenteroftheholecorrectly. lectrode that vibrates as it is fed into the work. Misalignmentcould 'he part that is to be disintegrated and resultintheelectrode the leaving the tap or stud and damagingthe part. A sating part that it is screwed intomust be made machinist's square laid on the table rom a material that will conduct electricity. or a dial indicator mounted on the disintegratinghead 5-31 151 MACHINERY REPAIRMAN 3 & 2

28.321 Figure 5-40.Metal disintegrator removing a broken stud.

5-32 Chapter 5POWER SAWSAND DRILLING MACHINES can be used to help align thepart. If the part will not make The coolant is pumpedfrom a sump to the an electrical ground to the table disintegratingheadand or if the model of machinebeing used is then throughthe designed as an attachment electrode, which is hollow,to the exact point of to be mounted ina the disintegrating action. drill press spindle, thedisintegrator's auxiliary The specific controls whichmust be set may ground cable must be attachedto the part. vary among the different Selection of the correctelectrode depends machines; however, on the diameter and length of most have a control to startthe disintegrating the part to be head vibrating anda selector switch for the heat removed. As a general rule,the electrode should be large enough in diameter or power setting. The position ofthis switch is to equal the smallest dependent on the diameterof the electrode diameter of a tap (thedistance between the being used. Some models halean automatic feed bottom of opposite flutes).To remove a stud, control the electrode must not thatregulatesth speedthat the be so large that it could electrode penetrates the burn or damage thepart if a slight misalignment part to be removed. is present. A scribe and Regardless of whether thefeed is automaticor a small magnet can be manual, it must not be used to removeany of the stud material not advanced so fast that it disintegrated. stops the disintegrating headand the electrode fromvibrating.Ifthis A free-flowing supply ofclean soluble oil is happens,the an essential part of the disintegrating disintegrating action willstop and the electrode operation. could be bentor broken.

5-33 153 CHAPTER 6

OFFHAND GRINDING OFTOOLS

One requirement for advancement in the MR techniques. Observance of safety precautions, ratingisto demonstrate ability to grind and posted on or near all grinders used by the Navy, sharpen some of the tools used in the machine is mandatory for the safety of theoperator and :hop. Equipment used for thispurpose includes the safety of personnel in the nearby vicinity. bench,pedestal,carbide, and chip breaker What are the most common sources of injury grinders and precision grinding machines. This during grinding operation? Hazards leadingto chapter contains informationon the use of these eye injury caused by grit generated by the grinders and the grinding of small toolswhile grinding process are the most common and the using the offhand grinding technique. (Precision mostserious.Abrasions caused bybodily grinding machines will be discussed ina later contact with the wheel are quite painful and chapter.) can be serious. Cuts and bruises caused bysegments of an exploded wheel, or a tool- "kicked"away Grinding is the removal of metal bythe from the wheel are other sources of injury. Cuts cuttingactionof anabrasive.In offhand and abrasions can become infectedif not grinding you hold the workpiece inyour hand protected from grit and dust produced during and position it as needed while grinding. To grinding. grind accurately and safely, using the offhand Safety in using -bench and pedestal grinders method, you must have experience and practice. is primarily a matter of usingcommon sense and In addition, you must know howto install concentrating on the job at hand.. Each timeyou grinding wheels on pedestal and bench grinders, start to grind a tool, stop briefly to consider how to sharpen or dress them, and you must how observance of safety precautions andthe knowthesafetyprecautionsconcerning use of safeguards protect you from injury. grinding. Consider the complications that could becaused by loss of your sight, or lossor mutilation of an Toproperlygrindsmallhandtools, arm or hand. single-edged cutting tools, and twist drills,you Some guidelines for safe grinding practices must know the terms used to describe the angles are: and surfaces of the tools. You must alsoknow the operations for which each tool isused, and Read posted safety precautions before you must know the composition of the tool starting to use a machine. In additionto material. refreshing your memory about safe grinding practices, this gets your mindon the job at hand. GRINDING SAFETY Secure allloose clothing and remove The grinding wheel isa fragile cutting tool rings or other jewelry. which operates at high speeds. Therefore,the safe operation of bench and pedestal grindersis Inspect the grinding wheel, wheel guards, asimportant to you aslearninggrinding the toolrest, and other safety devicesto ensure

6-1 154 MACHINERY REPAIRMAN 3 & 2 theyarein good condition and positioned mounted on a workbench. They are used foi properly. Set the toolrest so that it is within 1/8 grinding and sharpening smalltools such as inch of the wheel face and level with the center lathe, , and shaper cutting tools; twist of the wheel. drills; and handtools such as chisels and center punches. These grinders do not have installed Transparent shields, if installed, should coolant systems; however, a container of water be clean and properly adjusted. Transparent is usually mounted on the front of the grinder. shields do not protect against dust and grit that may get around a shield. You must ALWAYS Grinding wheels up to 8 inches in diameter wear goggles while grinding. Goggles with side and Iinch in thickness are normally used on shield give the best eye protection. bench grinders. A wheel guard encircles the grinding wheel except for the work area. An Stand aside when starting the grinder adjustable toolrest, steadies the workpiece and motor untilithas run for I minute. This can be moved in or out or swiveled to adjust to preVents injury in case the wheel explodes from grindingwheels of differentdiameters. An a defect that you did not notice. adjustable eye shield made of safety glass should be installed on the upper part of the wheel guard Use light pressure when starting grinding; and positioned to deflect the grinding wheel too much pressure on a cold wheel may cause particles away from the machine operator. failure. Pedestal grinders are usually heavy duty On bench and pedestal grinders, grind bench grinders which are mounted on a pedestal only on the face or periphery of a grinding fastened to the deck. In addition to the features wheel unless the grinding wheel is specifically of the bench grinder, pedestal grinders normally designed for side grinding. have a coolant system which includes a pump, storage sump, and a hose and fittings to regulate Use a coolant to prevent the work from and carry the coolant to the wheel surface. overheating. Pedestalgrinders areparticularly useful for rough grinding suchas "snagging" castings. BENCH AND PEDESTAL GRINDERS Figure 6 -2 shows a pedestal grinder in use.

Benchgrinders(fig.6-I)aresmall self - containedgrinderswhichareusually GRINDING WHEELS

A grinding wheel is composed of two basic elements: ( I) the abrasive grains, and (2) the bonding agent. The abrasive grains may be compared to many single point tools embedded in a toolholder or bonding agent. Each of these grains removes a very small chip from the workpieceasitmakescontactoneach revolution of the grinding wheel.

An ideal cutting tool is one that will sharpen itself when it becomes dull. This, in effect, is what happens to the abrasive grains. As the individual grains become dull, the pressure that is generated on them causes them to fracture and present new sharp cutting edges to the 28.328 work. When the grains can fracture no more, the Figure 6-1.Bench winder. pressure becomes too great and they are released

6-2 155 Chapter 6OFFHAND GRINDING OF TOOLS

TYPE STRAIGHT

TYPE 2 CYLINDER

TYPE t CUT-OFF

TYPE 6 STRAIGHT CUP

TYPE 5 RECESSED ONE S'OE

TYPE T RECESSED TWO StOE TYPE II FLARING CUP

TYPE 12 DISH TYPE 13 SAUCER

28.309 28.61 Figure 6-3.Grinding wheel shapes. Figure 6.2. Grinding on a pedestal grinder.

downthemarkingandexplainseach rom the bond, allowing new sharp grains to stationtype of abrasive, grain size, bond grade, ontact the work. structure, type of bond and the manufacturer's record symbol. Study this information carefully IIZEF AND SHAPES as it will be invaluable to you in making the proper wheel selection for each grinding job you Grinding wheels come in various sizes and attempt. ['apes.Thesizeof agrindingwheelis etermined by itsdiameterininches,the iameter of the spindle hole, and the width of Type of Abrasive he face of the wheel. All the shapes of grinding rheels are too numerous to list in thismanual, ut figure 6-3 shows most of the frequently used The first station of the wheel marking isthe theel shapes. The type numbersare standard abrasive type. There are two types of : rid are used by all manufacturers. The shapes natural and manufactured. Naturalabrasives, re shown in cross-sectional views. The specific such as emery, corundum, and diamond,are 1:1 will dictate the shape of the wheelto be used only in honing stones and in special sed. types of grinding wheels. Thecommon manufactured abrasivesarealuminumoxide andsilicon HEEL MARKINGS AND COMPOSITION carbide. They have superior qualities andare moreeconomicalthannaturalabrasives. Grinding wheel markingsare comprised of Aluminum oxide (designated by theletter A) is x stations. Figure 6-4 illustrates the standard used for grinding steel and steel alloys andfor arking.The followinginformation breaks heavy duty work such as cleaningup steel

6-3 1,G MACHINERY REPAIRMAN 3 & 2

C 60 I 9 V

ABRASIVE GRAIN BOND BO ND STRUCTURE TYPE SIZE GRADE TYPE

A- ALUMINUM 10 A-SOFT 1 - DENSE -40V-VITRIFIED 4.MANUFACTURER'S OXIDE 12 B 2 RECORD C-SILICON 14 C 3 S SILICATE SYMBOL CARBIDE 16 0 4 E 5 R-RUBBER 20 F 6 24 0 7 S- RESINOID H-TO 9 TO I E-SHELLAC 910 11 0-OXYCHLOR- 600 12 IDE 13 N 14 15 - OPEN

Z-HARD

28.310 Figure (M.Standard marking system for winding wheels (except diamond). castings. Silicon carbide (designated by the letter Bond Grade (Hardness) C),whichisharder butnotastoughas aluminum oxide, is used mostly for grinding Station three of the wheel marking is the nonferrousmetalsandcarbidetools.The grade or hardness of the wheel. As shown in abrasive in a grinding wheel comprises about figure 6-4, the grade is designated by a letter of 40% of the wheel. the alphabet; grades run from A to Z, or soft to hard. The grade of a grinding wheel is a measure of Grain Size the bond's ability totain the abrasive grains in the wheel. Grinding wheels have a soft to a hard grade. This does not mean that the bond or the The second station on the grinding wheel abrasive is soft or hard; it means that the wheel marking is the grain size. Grain sizes range from has a large amount of bond (hard grade) or a. 10 to 600. The size is determined by the size of small amount of bond (soft grade). Figure 6-5 mesh of a sieve through which the grains can shows a magnified portion of a soft grade and a pass. Grain sizeis rated as follows: Coarse: hard grade wheel. You can see by the illustration 10,12, 14, 16, 18, 20, 24; Medium: 30, 36, 46, that a part of the bond surrounds the abrasive 54, 60; Fine: 70, 80 90, 100, 120, 150, 180; and grains, and the remainder of the bond forms into Very Fine: 220, 240, 280, 320, 400, 500, 600. posts which both hold the grains to the wheel Grain, sizesfinerthan240aregenerally and hold them apart from each other. The wheel considered flour. Fine grain wheels are preferred with the larger amount of bonding material has for grinding hard materials, as they have more thick bond posts and will offer great resistance cutting edges and will cut faster than coarse to pressures generated in grinding. The wheel grain wheels. Coarse grain wheels are generally with the least amount of bond will offer less preferred for rapid metal removal on softer resistance to the grinding pressures. In other materials. words, the wheel with a large amount of bond is

1 5 64 Chapter 6OFFHAND GRINDING OF TOOLS

ABRASIVE Bond Type GRAIN The fifthstation on the grinding wheel BOND marking is the bond type. The bond comprises COATING the remaining 40% of the grinding wheel and is OPEN SPACE one of the most important parts of the wheel. The bond determines the strength of the wheel. BOND POST The six basic types of bondsare vitrified, silicate,rubber,resinoid,shellac,and oxychloride. WHEEL A VITRIFIED BOND.Designated bythe letter V, this is the most common bond used today in grinding wheels. Approximately 75% of all grinding wheels are made with vitrified bond. This bond is not affected by oil, acid,or water. Vitrified bonded wheels are strong andporous, and rapid temperature changes have littleor no effect on them. Vitrified bond is composed of specialclays. When heated to approximately 2300°F the clays forma glass-like cement. Vitrified wheels should not be run faster than 6500 surface feet per minute.

WHEEL B SILICATE BOND.Silicate bonded wheels ardesignated by the letter S. The bond is made of silicate of soda. Silicate bonded wheelsare 28.311 used mainly for large, slow rpm machines where Figure 6-5.How bond affects the grade of the wheel acooler cutting actionisdesired.Silicate Wheel A, softer; 'wheel B, harder. bonded wheels are softer than vitrified wheels; theyreleasethegrains more readilythan vitrified bonded wheels. Silicate bonded wheels a hard grade and the wheel with a small amount are heated to approximately 500°F when they of bond is a soft grade. are made. This wheel, like the vitrified bonded wheel, is not to be run at a speed greater than Structure 6500 feet per minute. RUBBER BOND.Rubber bondedwheels The fourth station of the grinding wheel are designated by the letter R. The bond consists markingisthe structure. The structureis of rubber with sulphur addedas a vulcanizing designated by numbers from I to15,as agent. The bond is made intoa sheet into which illustiatedinfigure6-4. The structure of a the grains are rolled. The wheel is grinding wheel refers to the stamped out open space between of this sheet and heated ina pressurized mold the grains, as shown in figure 6-5. Grains that are untilthevulcanizingactioniscompleted. very closely spaced are said to be dense; when Rubber bonded wheelsare very strong and are grains are wider apart, they are said to beopen. elastic. They are used in makingthin cutoff The metal removal will be greater for open-grain wheels and are used extensivelyfor regulating wheels than for close-grain wheels. Alsodense, wheels on centerless grinders. or close grain, wheels will normally produce Rubber bonded a wheels produce a high finish andcan be run at finer finish. The structure of a grinding wheel speeds between 9,500 and 16,000surface feet comprises about 20% of the grinding wheel. per minute.

6-5 1 5 MACHINERY REPAIRMAN 3 & 2

RE SI N OI D B ON D.Resinoidbonded similarly to aluminum-oxide and silicon-carbide wheels are designated by the letter B. Resinoid wheels, although there is not a standardsystem. bond is made from powderedor liquid resin Thefirststationisthe type of abrasive, with a plasticizer added. The wheelsare pressed designated DfornaturalandSDfor and molded to size and fired at approximately manufactured. The second station is the grit size 320°F. Resinoid wheelsare shock resistant and which can range from 24 to 500. A 100-grain very strong. They are used for rough grinding size might be used for rough work, and and as a 220 for cutoff wheels.Resinoid wheels like finish work. In a Navy machine, shop,you might rubber bonded wheels can berun between the find a 150-grain wheel anduse it for both rough speed of 9,500 to16,000 surface feet per and finish grinding. The third station is the minute. grade, designated by letters of the alphabet. The fourth station is concentration, designated by SHELLAC BOND.Shellac bonded wheels numbers. The concentration or proportion of are designated by the letter E. Wheels of this diamonds to bond might be numbered 25, 50, type are made from a secretion from Lac bugs. 75 and 100 going from low to high. The fifth The abrasive and bond are mixed and moldedto stationisthe bond type, designated B for shape and are baked at approximately 300°F. resinoid, M for metal, and V for vitrified. The Shellac bonded wheels givea high finish and sixth station may or may not be used; when have a cool cutting action when usedas cutoff useditidentifiesbondmodification. The wheels.Shellac bonded wheelscan be run seventh station is the depth of diamond section. between 9,500 and 12,500 surface feetper This is the thickness of the abrasive layer and minute. ranges from 1/32 to 1/4 inch. Cutting speeds from 4,500 to 6,000 surface feetper minute OXYCHLORIDE BOND.Oxychloride should be used. bonded wheels are designated by the letter 0. Oxychloride bond is made from chemicals andis a form of cold-setting cement. This bond is GRAIN DEPTH OF CUT seldom, if ever, used in grinding wheels but is used extensively to hold abrasiveson sanding disks. Oxychloride bonded wheelscan be run at On most ships, stowagespace is limited. speeds between 5,000 and 6,500 surface feetper Consequently, the inventory of grinding wheels minute. must be kept to a minimum. It would be impracticable and unnecessary to keepon hand Manufacturer's Record Symbol a wheel for each and every grinding job. Witha knowledge of the theory of grain depth ofcut you can vary the cutting action of the various The sixth station on the grinding wheel wheels and with a small inventorycan perform marking is the manufacturer's record. Thismay practically any grinding operation thatmay be be a letter or number,or both. It is used by the necessary. manufacturer to designate bond modifications or wheel characteristics. Foreaseinunderstandingthistheory, assume that a grinding wheel has a single grain. DIAMOND WHEELS When the grain reaches the point ofcontact with the work, the depth of cut iszero. As the wheel and the work revolve, the depth ofcut will Diamond grinding wheels are classedby increase to a maximum at some point along the themselves.Wheelsofthistypearevery arc of contact. Since the wheel rotates much expensive and should be used withcare and only faster than the work, the greatest depthof cut for grinding carbide cutting tools. Diamond will be near the spot where the grainloses wheelscanbemade fromnaturalor contact with the work. This greatest depthis manufactureddiamonds.Theyaremarked called the grain depth of cut.

6-6 159 Chapter - A./.; %'!..Nf_y OF TOOLS

Part A of figure 6-6 illustrate,c;:. finding size. The speed of both the work and the wheel wheel and a workpiece; ab is the raa:al depth of remains the same. The length of thearc of cut, ad is the arc of contact, and of is the grain contact ad is greater than the aic of contact ad' depth of cut. As the wheel rotates, the grain so that the chips cut by both the original size moves from the point of contact to point d in a wheel and the -.mailer size wheel are of thesame given amount of time, and at thesame time volume, but since the arc of contact of the point d on the workpiece moves to pointe. The smaller wheel is less, the thickness of the chip is workpiece generally rotates at a much slower greater. From this theory you can see that the speed than the wheel; consequently, length de grain depth of cut increases as the diameter of will be less than ad. During a given amount of the wheel decreases, and the wheel will act time the grain will remove a chip represented by softer. This is true because the area of contact ade. between the wheel and the work decreases, but Referring to part B of figure 6-6,assume the pressure exerted on the grains increases. that the wheel has worn down toa much smaller Consequently, the grains are torn from the wheel sooner. Based on this theory, increasing the grain depth of cut applies more pressureper grain and causes the wheel to act softer; decreasing the grain depth of cut decreases thepressure per grain and causes the wheel to act harder. The following actions show the changes thatmay be made to make the wheel act a certain way. RADIAL DEPTH INCREASE THE GRAIN DEPTH OF CUT OF CUT ab (SOFTER WHEEL)

GRAIN Increase the work speed DEPTH Decrease the wheel speed OF CUT of Reduce the diameter of the wheel

DECREASE THE GRAIN DEPTH OF CUT (HARDER WHEEL)

Decrease the work speed Increase the wheel speed Increase the diameter of the wheel

GRINDING WHEEL SELECTION AND USE

Theselectionofgrindingwheolsfor precision grinding can be discussed'generally in terms of such factors as the physical properties of the material to be ground, the amount of stock to be removed (depth of cut), the wheel speed and work speed, and the finish required. B Selection of a grinding wheel that has theproper abrasive, grain, grade, and bond is determined by one or more of these factors. 126.41X An aluminum oxide abrasive is most suitable Figure 6-6.Grain depth of cut; center type machine. for grinding carbon and alloy steel, high-speed

6-7 1t,ll MACHINERY REPAIRMAN 3 & 2

Table 6-1.Recommendations for SelectingGrinding Wheels

OPERATION WHEEL DESIGNATION MATERIAL

AbrasiveGrainGradeStructure Bond Mfg. size Symbol Cylindrical A 60 K 3 V grinding High-speed steel A 60 L 5 V Hardened steel A 54 M 5 V Soft steel A 36 G 12 V Stainless steel C 36 K 5 V Cast iron, brass, aluminum A 60 G 12 V Nickel copper (Monel) A 54 L 5 V General purpose A 46 H 8 V High-speed steel A 60 F 12 V Hardened steel A 46 J 5 V Soft steel A 36 G 12 V Stainless steel C 36 J 8 V Cast iron and bronze A 60 G 12 V a Nickel copper (Monel) A 24 H '8 V General purpose Tool and A 46 K 8 V cutter grinding High-speed steel or cast alloy A 54 L 5 V Reamers A 60 K 8 V Taps

28.263.0 steel, cast alloys and malleable iron. Asilicon a coolant also permits the use of a harder grade carbide abrasive is most suitable for grinding of wheel. Table 6-1 listsrecommended grinding nonferrous metals, nonmetallic materials,and wheels for various operations. cemented carbides. Figure 6-7 shows the type of Generally, the softer and more ductile fp ;nding wheel the used on bench and pedestal grinders.When you material being ground, thecoarser should be the replace the wheel besure that the physical grainselected.Also, if alarge amount of dimensions of the new wheelare correct for the material is to be removed,a coarse grain wheel is grinder on which it will be used. recommended (except on The outisde very hard materials). diameter, the thickness, and the spindlehole size If a good finish is required,a fine grain wheel are the three dimensions that must be checked. should be used. If the machine you are using is An adapter (bushing)may be used to decrease worn, a harder grade may be necessary to help the size of the spindle hole,so that it fits your offset the effects of wear on the machine.Using grinder.

6-8 1 61 Chapter 6OFFHAND GRINDING OF TOOLS

GRINDING PAPER WHEEL OLDTTER

INNER . CUTTER FLANGE FLANGE STRAIGHT WHEEL

LEAD RELIEF BUSHING Figure 6-7.Grinding wheel for bench andpedestal AREA grinders.

WASHER

The wheels recommended for grindingand sharpening single point (lather, planer, shaper, etc) tool bits made from high-carbonsteel or MOTOR SHAFT high-speed steel are A3605V (coarse wheel) and A60M5V (fine or finish wheel). Stellitetools shouldbe ground on a wheel designated NUT A46N5V. These grinding wheels, whichhave aluminum oxide as an abrasive material, should be used to grind steel and steelalloys only. Grindingcastiron,nonferrousmetalor nonmetallicmaterialtwiththesegrinding wheels will result in loadingor pinning of the wheel as the particles of the material being ground oecome imbedded in thepores of the grinding wheel. This condition putsa strain on the wheel and could cause it to fail withpossible injury to someone nearby. 28.62(28D) Figure 6-8.Method of mountinga grinding wheel. WHEEL INSTALLATION material. Place the inner flange in place and The wheel of a bench or pedestal grinder follow it with a blotter. NOTE: The blotter must be properly installed; otherwise, the wheel thickness for paper must be no thickerthan will not operate properly and accider+.may 0.025 inch and no thicker than 0.125 inchfor occur. Before a wheel is installed, it should be leather or rubber. The blotter is used toensure inspected for visible defects and "sounded"to even pressure on the wheel and to dampen the determine whether it has invisible cracks.To vibration between the wheel and shaft whenthe properly sound a wheel, hold itup by placing a grinder is in operation. hammer handle or a short piece of cordthrough the spindle hole. Using a nonmetallic objectsuch Next, mount the wheel, andensure that it as a screwdriver handle or small wooden mallet, fits on the shaft without play. There should bea tap the wheel lightly on the side. Rotatethe 0.002- to 0.005-inch clearance. Youmay need wheel 1/4 of a turn (90°) and repeat. Agood to scrape or ream the lead bushing in thecenter wheel gives out a clear ringing soundwhen of the wheel to obtain this clearance. NEVER tapped, but if the wheel is cracked,a dull thud is FORCE THE WHEEL ON THE SHAFT.Forcing =produced. the wheel on the shaft maycause the wheel to crack when placed in operation,or cause the You will find it easier to understandthe wheel to be slightly out of axial alignment. following information on mounting the wheel if The next item is another blotter andthen you refer to figure 6-8. Ensure that the shaft and the outer flange. NOTE: the flangesare recessed flanges are clean and free of grit and old blotter so they provide an even pressure on the wheel.

6-9 I C2 MACHINERY REPAIRMAN 3 & 2

The flanges should be at least one-thirdthe diameter of the wheel. SAFETYHOOD Next, install the washer and WHEEL' secure the nut. DRESSER Tighten the securing nut sufficientlyto hold the $- wheel firmly; tightening too muchmay damage the wheel.

TRUING AND DRESSING THE WHEEL Grinding wheels, like other cutting tools requirefrequentreconditioningofcutting surfaces to perform efficiently. Dressing isthe 28.63 process of cleaning the cutting face of grinding Figure 6-9.Using a grinding wheel dresser. wheels. This cleaning breaksaway dull abrasive grains and smooths the surfaceso that there are no grooves. Truing is the removal of material motor with the shaft extended at each end for from the cutting face of the wheelso that the mounting the grinding wheels; the pedestal' resulting surface runs absolutely trueto some which supports the motor and is fastenedto the other surface such as the grinding wheel shaft. deck; wheel guards whichare mounted around The wheel dresser shown in.figure 6-9 is used the circumference and back of thegrinding fordressing grinding wheels on bench and wheels as a safety device; andan adjustable pedestal grinders. To dressa wheel with this toolrest mounted in front of each wheelfor tool, start the grinder and let itcome up to supporting the tool bits while theyare being speed. Set the wheel dresseron the rest as shown ground. in figure '6-9 and bring it in firmcontact with the wheel. Move the wheel dresseracross the periphery of the wheel until the surface isclean and approximately square with the sidesof the wheel. If grinding wheels get out of balance because of out-of-roundness, dressing the wheel will usually remedy the condition. A grinding wheel can get out of balance if part of the wheel is immersed in coolant. If this happens,remove the wheel and dry it out by baking. If the wheelgets out of balance axially, it probably will not affect theefficiency of the wheel on bench and pedestalgrinders.This unbalance may be remedied simply by removing the wheel and cleaning the shaft spindle and spindle hole inthe wheel and the flanges.

CARBIDE TOOL GRINDER

The carbide tool grinder (fig. 6-10)looks much like a pedestal grinder with the toolreston the sip instead of on the front. The main 28.329 components of the carbide tool grinderare: a Figure 6-10.Carbide tool grinder.

6-10 . 1G3 Chapter 6OFFHAND GRINDING OF TOOLS

type is sharpened on the carbidetool bit grinder. For best results in sharpening carbide tipped toolbits,use asiliconcarbide wheel for roughing and a diamond impregnated wheelfor finishing.

WHEEL SELECTION

The best results are obtained frotha carbide 28.284 by using four differentgrinding Figure 6-11.Crown on the working face of a wheel for wheels to sharpen them. The aluminumoxide a carbid, tool bit finder. wheel recommended for grindinghigh-speed steel tools should be used to grindthe steel shank beneath the carbide tip to the desired Unlikethepedestal end grinderwhere the and site cutting edge angles witha relief angle of grinding is done on the periphery of thewheel, approximately 15°. This angle is approximately the grinding wheels usedon 'Carbide tool bit double the clearance angle ground grinders have the cutting face on the on, the side of the carbide tip. The wheels for thecarbide tool wheel. The straight cup wheel (fig.6-11) is grinder should have silicon carbide similar to the wheels used as the on most carbide tool abrasive material. The'wheel usedto rough grind bit grinders. Some carbide tool grindershave a should be designated C6018V. Thewheel for straight cup wheel on one side of the grinder and semifinish grinding should be C100H8V.A a straight wheel, such as the type usedon a diamond impregnated grinding wheel pedestal or bench grinder, with the on the other side. designation SD 220-P5OV is recommendedfor the finish grin ing of carbide tipped tools. The adjustable toolrest hasan accurately ground groove or keywayacross the top of its table. This groove is for holdinga protractor attachment which can be set to thedesired OPERATION OF THE CARBIDE cutting edge ,angle. The toolrest will alsoadjust TOOL GRINDER to permit grinding the relief angle. Some carbide tool grinders havea coolant The sharpening of a carbide tippedtool bitis system. When coolantisavailable, the tool accompliited in the followingmanner. should have an ample, steadystream of coolant directed at the point of grinding wheelcontact. Using a grinder with an ALUMINUM An irregular flow of coolantmay allow the tool OXIDE wheel, grind side relief andend relief to heat up and then be quenchedquickly, angles on the STEEL shanks. Caution:NEVER resulting in cracks to the. carbide. Ifno coolant grind steel shanks with silicon carbidewheels. system is available, do NOT dip the carbideinto a container of water when it becomes hot. Allow it to air cool. Dress the silicon carbide wheelwith a star type wheel dresser. Ferna 1/16-inchcrown Carbide tipped tool bitsmay be (1) the on the working face of chc wheel to rtitrnize disposable tip type where the tip hasthree or the amount of contact between the tfpnd-Ilre,, more pre-ground cutting edges or (2) the brazed wheel (fig. 6-11). tip type where the cutting edgesmust be ground into the tip. The disposable tiptype tool bit Using the graduated needs no sharpening; the tips 'al on the side of are disposed of as the toolrest, adjust the too est tothe desired their cutting edges become dull.-The brazedtip side clearance angle.

6-11 164 MACHINERY REPAIRMAN 3 & 2 Place the protractor on the toolrest with the protractor keyinthe keyway. Set the protractor to the proper side cutting edge angle. Hold the shank of the tool bit firmly against the side of the protractor;move the tool bit back and forth across the wheel, keepinga steady, even pressure againstthe wheel. To prevent burning the carbide tip, keep the tool bit continually in motion while grinding it.

Carbide tipped cutters may be rough ground and finish ground with silicon carbide wheels. Generally, when a carbide tool chip grinder is available,thefinishgrindingoperationis performed on this machine witha diamond wheel. The chip grinder is 'very similarto the carbide tool bit grinder except that the wheels are smaller and diamond impregnated. Dry grinding is generally done when silicon carbide wheels are used. When using diamond wheels, be sure to use coolanton the tool and wheel face. NEVER allow the steel shankto come into contact with a diamond wheel as this will immediately load the wheel.

CHIP BREAKER GRINDER

A chipbreaker grinder (fig.6-12)isa specialized . It is designedto 28.330 permitaccurategrindingofgroovesor Figure 8-12.Chip breaker grinder. indentations on the top surface of carbide tools, so that the direction and length of the chips produced in cutting metal can be controlled. A wheel but differs from other type 1 wheelsthat description of the various types of chip breakers you will use in that it is normally less than 1/4 that are commonly ground on carbide tools will inch thick. An SD 150 R 100B grindingwheel is be presented later in this chapter. normally recommended. The chip breaker grinder hasa vise, which can be adjusted to four different angles, to hold Chip breaker grinders havea coolant system the tool to he ground. These anglesthe side that either floods or slowly drips coolanton the cutting edge, back rake, side rake, and the chip tool being ground. The main objective inusing breakerare explained later in this chapter. The coolant is to prevent the grinding wheel from vise is mounted so it can be moved backand loading up or glazing over from the grinding forth under the grinding wheel. Both thecross operation. feed, for positioning the tool under thegrinding wheel, and the vertical feed, for controlling the SINGLE-POINT CUTTING TOOLS depth of the chip breaker,are graduated in increments of 0.001 inch. A single-point or single-edged cutting toolis A diamond wheel is used on the chip breaker atool which has only one cutting edgeas grinder. The wheel is usually a typeI straight opposed to two or more cutting edges. Drillbits

6-12 Chapter 6OFFHAND GRINDING OF TOOLS are multiple-edged cutters, most lathe tools are of the tool bit and either away from or toward single edged. To properly grind a single-point the side cutting edge. The amount of side rake cutting tool, jou must know the relief angles, influences to some extent the size of the angle the rake angles, and the cutting edge angles that of keenness. It causes the chip to "flow" to the are required for specific machines and materials. side of the tool away from the side cutting edge. You mustknowalsowhatmaterialsare The side rakeis positiveif the angle slopes generally used for cutting tools and how tools downward from the side cutting edge toward the for various machines differ. opposite side of the tool, and negative if it slopes upward. A positive side rake is most often Cutting Tool Terminology used on ground single-point tools. Generally, the side rake angle will be steeper (in the positive Figure 6-13 shows the application of the direction) for cutting the safety metals and will anglesandsurfacesweuseindiscussing decrease as the hardness of the metal increases. single-point cutting tools. Notice that there are A steep side rake angle in the positive direction two relief angles and two rake angles and that causes the chip produced in cutting to be long the angle of keenness is formed by a rake and a and stringy. Decreasing the angle will cause the relief angle. chip to curl up and break more quickly. A negative side rakeis recommended when the SIDE RAKE.Side rake (fig. 6-13A) is the tool will be subjected to shock, such as an angle at which the top surface of the tool is interrupted cut or when the metal being cut is round away with respect to the bottom surface extremely hard.

SIDE RAKE ANGLE BACK RAKE ANGLE

80 B

FLANK SHANK

A., 6° TOOL BASE

ANGLE SIDE RELIEF END RELIEF AN KEENNESS

END CUTTING EDGE ANGLE

C

NOSE HADIUS

15° SIDE CUTTING EDGE ANGLE --1"

28.84 Figure 13-13.Applications of tool terminology.

6-13 MACHINERY REPAIRMAN 3 & 2

BACK RAKE.The back rake (fig. 6-13B) is the angle should be as largeas the machining the angle at which the top surfaceto the tool is operation will allow. ground away with respect to the bottom surface of the tool and perpendicular to the side rake END CUTTING EDGE:The endcutting angle. It is ground primarily tocause the chip edge angle (fig. 6-13C) is groundon the end of cut by the tool to "flow" back toward the shank the tool to permit thenose to make contact of the to.1. Back rake may be positiveo with the work without the tool draggingthe negative; itispositiveif it slopes downwaM surface. An angleof from 8° from the nose of the tool toward the shank, to 30°is or commonlyusedwithapproximately15° negative if a reverse angle is ground. Therake recommended for rough turning operations. angles aid in forming the angle of keennessand Finish operations can be made withthe end in directing the chip flow away from the point cutting edge angle slightly larger. Too largean of cutting. The same general recommendatfons end cutting edge angle will reduce the concerning positive or negative side rake support angles given the nose of the tool and couldcause apply to the back rake angle. premature failure of the cutting edge.

SIDE RELIEF.The side relief (fig.6-13A) NOSE.The nose (fig. 6-13C) strengthens is the angle at which the sideor flank of the tool the tip of the tool, helps tocarry away the heat is ground so that the si4 cutting edgeleads the generated by the cutting action and helpsto flank surface when cutting. The side reliefangle, obtain a good finish. A radius (rounded end)of like the side rake angle, influences theangle of from 1/64 to 1/32 inch is normally usedfor keenness. The total of the side rake andside turning operations. A tool that is used withthe relief subtracted from 90° equals theangle of nose ground to a straight point will fail much keenness. A tool with proper side reliefcauses more rapidly than one which has hada slight the side thrust to be concentratedon the cutting radius ground or honed on it. However,too large edge rather than rubbingon the flank of the a radius will cause chatter because of excessive tool. tool contact with the work

END RELIEF. The end relief (fig. 6-13B)is the angle at which the end surface ofthe tool is GROUND-IN CHIP BREAKERS ground so that the front face edge of thetool leads the front surface. Chip breakers are indentations groundon the top surface of the tool that helpreduce or ANGLE OF KEENNESS.The angle prevent the formation of long and dangerous of chips. The chip breaker will keenness or wedge angle (fig. 6-13A) isformed cause the chips to by the side rake and the side relief ground curl up and break Into short, safe,manageable in a chips.Chip breakers are ground mostly tool. Generally, for cutting soft materialsthis on angle is small, Ithan for cutting hard materials. roughing tools,but they can be groundon finishing tools used to machine softductile metals. Figure 6-14 shows four ofthe several SIDE CUTTING EDGE.The sidecutting types of chip breakers thatcan be around onto edge angle (fig. 6-13C) is groundon the side of the cutting tool. the tool that is fed into the work. This anglecan be anywhere from On for cutting to a shoulder, The dimensions given are general andcan be up to 30° for straight turning. An angle of 15° is modified to compensate for thevarious feed recommendedformostroughturning rates, depths of cut, and types of material operations. In turning long slender shifts, being a side machined. The groove type chip breakermust be cutting edge angle that is too largecan cause carefully ground to prevent it from chatter. Since the pressure coming too on the cutting edge close to the cutting edge whichreduces the life and the heat generated by the cuttingaction of the tool due to decreased decrease as the side cutting edge angle support of the increases, cutting edge. Chip breakerson carbide tipped 6.14 1G7 Chapter 6OFFHAND GRINDING OF TOOLS

Some types contain small amounts of chromeor vanadium to increase the degree of hardnessor toughness. Carbon steel is limited in its use,as a

TIMES cutting tool material because of its low tolerance RADIUS to the high temperatures generated during the EJA cutting process. Jobs made from carbon steel Vos willbegin to lose their hardness, 50 to 64 TOP VIEWS Rockwell"C,"ata temperingrangeof approximately 350° to 650°F. Carbon steel tools perform best as lathe cutting tools when used to take light or finishing cutson relatively 32 soft materials such as brass, aluminum, and unhardened low carbon steels. The cutting speed PARALLEL SHOULDER GROOVE ANGULAR for carbon steel tools should be approximately 50% of the speeds recommended for high-speed ENO VIEWS. steel tools.

28.333 Figure 6-14.Chip breakers. HIGH-SPEED STEEL

High-speedsteelisprobablythemost tools can be ground with the diamond wheelon common cutting tool material used in Navy the chip breaker grinder. High-speed steel tools machineshops.Unlikecarbonsteeltools, must beground with an aluminum oxide high-speed steel tools are capable of maintaining grinding wheel. This can be doneon a bench their hardness and abrasion resistance under the grinder by dressing the wheel until it hasa sharp hightemperaturesandpressuresgenerated edge or by using a universal vise whichcan be set during the general cutting process. Although the to compound angles on a surface or tool end hardness of the high-speed tool (60 to 70 cutter grinder. Rockwell "C") is not much greater than the carbon steel tools, the tempering temperatureat which high-speed steel begins to lose its hardness CUTTING TOOL MATERIALS is 100° to 1100°F. Thereare two types of high peed steel tools which are generally used in The materials used to make machine cutting machine shops. They are tungsten high-speed tools must have the hardness necessary to cut steel and molybdenum high-speed steel. These other metals, be wear resistant, have impact designations are used to indicate the major strength to resist fracture, and be able to retain alloying element in each of the two types. Both theirhardnessandcuttingedgeathigh types have similar characteristics in their ability temperatures.Thereareseveraldifferent to resist abrasive wear, remain hard at high materials which are used for cutting tools and temperatures, and in their degree of hardness. each one has properties different from the The molybdenum typehigh-speedsteelis others.Selectionof a specific cutting tool tougher than the tungsten type and ismore material depends on the metal being cut and effectiveinmachineryoperationswhere conditions under which the cutting is being interrupted cuts are present. done. During interrupted cuts, suchas cutting out-of-round or slotted material, thecutter CARBON TOOL STEEL contacts the material many times inashort period of time. This "hammering" effect dullsor The carbon steel used to make cutting tools breaks cutters which are not tough enoughto usually contains from 0.90% to 1.40% carbon. withstand the shock effect. MACHINERY REPAIRMAN 3 & 2

CAST ALLOYS BRAZED ON TIP

Cast alloy tool steel usually contains varyinj, The brazed on carbide tip cutting toolwas amounts ofcobalt,chrome, tungsten,anti thefirst carbide cutting tool developed and molybdenum. Tools made from these steelsart- n.ade available to the metal cutting industry. generally more efficient than high-speed steel, The insert type of carbide tip has becomemore providing a tool that retains its hardnessup to widely used because of the ease in changing anoperatingtemperature of approximately cutting edges. There are some jobs which have 1400°F. This characteristic allows cutting speeds shapes or radii that cannot be readily formed approximately 60% greaterthan high-speed with a standard shaped insert, whilea brazed on steel. However, cast alloy toolsare not as tough tipiseasily ground to machine them. The asthehigh-speedsteeltools and therefore various styles of tools required in machinery, cannot be subjected to the same cutting stresses, such as turning, facing, threading, and grooving such as ,interrupted cuts. Clearances thatare in are available with different grades of carbide ground on cast alloy cutting toolsare loss than tips already brazed onto steel shanks. Small those ground on high-speed steel tools because carbide blanks are also available thatcan be of thg lower degree of toughness. Toolsmade brazed onto a shank by the machinist. from this metal are generally known under trade names such as Stellite, Rexalloy, and Fantung. Brazing on a carbide tip is a relatively simple operation that can be performed byanyone qualified to operate an oxyacetylene torch. The CEMENTED CARBIDE first step is to thoroughly clean the steel shank by grinding or sandblasting and degreasingit Cemented carbides, or sintered carbidesas with an approved solvent. The steel shanks and they are sometimes called, can be used at cutting the carbide tip should be completely coated speeds of two to four times those listed for with a flux to further remove any contamination high-speed steel. The softest carbide grade is and to prevent oxidation during brazing. A thin equal in hardness to the hardest tool steel andis shim-like brazing alloy is available thatcan be capable of maintaining its hardness and abrasive cut to the size needed and placed between the resistance up to approximately 1700°F. Carbide shank and the carbide tip. This type of bronze is much more brittle thanany of the other alloyis better than the rod type because it cutting tool materials previously describedin results in a more uniform and stronger bronze. this chapter. Because (..f this, interruptedcuts Heating of the tool should be started fromthe should be avoided and the machine setup should bottom of the shank. Raise the temperature be as rigid and vibration free as possible. There slowly until the bronze alloy melts. Tapthe are many different grades of carbides, each grade carbide tip gently to ensurea firm seat onto the being more suited for a particular machining shank and then let the tool cool in theair. operation and metal than the others. Carbide Quenching the tool in water will eithercause the manufacturers normally have available charts carbide tip to crack or prevent the bronzeband that match the correct grade forany given from holding the tip in place. After thetool is cutting application. Due to th.1 brittleness of cooled, it can be ground to the shape desired. carbide, it is seldom used ina solid form as a cutting tool. The most common usage is as a tip Chipcontrol,when cuttingtoolswith on a steel shank or on the cutting edge of a twist brazed-on carbide tips are used,may be provided drill.Carbide tipped lathe cutting toolsare by either feeds and speedsor by chip breaker usually in the form of carbide tips brazedonto grooves ground into the top of the carbide tip. the end of a steel shank or as small variously Figure 6-14 shows examplas of the varioustypes shaped inserts, mechanically heldon the end of of chip breakers that are used. Usinga chip a steel shank. A brief descriptif - of these two breaker grinder with a diamond impregnated types of cuttersisincluded inhe following wheel is the best way to grinda chip breaker. paragraphs. However, itis possible to um.,a carbide tool

6-16

.1. Chapter 6OFFHAND GRINDING OF TOOLS grinder or a pedestal grinder wheel dressed so metals that are too hard for carbide tools to cut. that it has a sharp edge. The depth of the chip Additionally,ceramiccansustaincutting breakers averages about 1/32 inch, while the temperaturesof up to2000°F.Therefore, width varies with the feed rate, depth c cut and ceramic tools can be operated at cutting speeds materialbeingcut. Grind the chip breaker two to four times greater than cemented carbide narrow at first and widen it if the chip does not tools. curl and break quickly enough. These same types of chip breakers also may be used on Ceramic cutting tools are available as either high-speed steel cutters. solid ceramic or as ceramic coated carbide in several of the insert shapes available in cemented CARBIDE CUTTING TOOLS carbides and are secured in the toolholder by a INSERT TYPE clamp. Whenever you handle ceramic cutting tools, Mechanicallyheldcarbideinsertsare be very careful because they are very brittle and availableinseveraldifferentshapesround, will not tolerate shock or vibration. Be sure your square,triangular,diamondthreading,and lathe setup is very rigid and do not try to take groovingand in different thicknesses, sizes, and any interrupted cuts. Also ensure that the lathe noseradii.The inserts may haveeither a feed rate does not exceed 0.015 to 0.020 inch positive, a neutral, or a negative rake attitude to per revolution, as any rate exceeding this will thepart being cut. The rake attitudeisa subject the insert to excessive forces and may combination of the back rake of the toolholder, result in fracturing the insert. the amount of clearance ground along the edge of the insert beneath the cutting edge, and the Engine Lathe Tools ground-in chip breaker. An insert and its toolholder must have the Figure 6-15 shows the most popular shapes same .direction of rake. For instance, a negative of ground lathetool cutter bits and their rake toolholder requires a negative rake insert. applications. In the following paragraphs each of Whenever possible, select the negative rake set- the types shown is described. up because both sides of the insert can be used, thus doubling the number of cutting edges LEFT-HAND TURNING TOOL. This tool available on positive or neutral inserts. Be sure is ground for machining work when fed from to place a specially made shim, having the same left to right, as indicated in figure 6-15A. The shape as the insert, into the toolholder pocket cutting edge is on the right side of the tool and beneath the insert to provide a smooth and firm the top of the tool slopes down away from the support for the insert. Metho of holding the cutting edge. insert inthe toolholdervaryfromone manufacturer to another. Some inserts are held ROUND-NOSE TURNING TOOL.This in place by the cam-lock action of a screw tool is for general all-round machine work and positioned through a hole in their centers, while isusedfortaking lightroughing cuts and otherF.are held against the toolholder by a finishing cuts. Usually, the top of the cutter bit clamp. is ground with side rake so that the tool may be fed from right to left. Sometimes this cutter bit Chip control for carbide insert tooling is is ground flat on top so that the tool may be fed providedbytwodifferentmethods. Some in either direction (fig. 6-15B). inserts have a groove ground into their cutting surfaces. Other inserts have a chip breaker plate RIGHT-HAND TURNING TOOLThis is held by a clamp on top of their cutting surfaces. just the opposite of the left-hand turning tool Other than diamond tools, ceramic cutting and is designed to cut when fed from right to tools arc the hardest and most heat resistant left (fig. 6-I5C). The cutting edge is on the left cuttingtoolsavailabletothemachinist. A side. This is an ideal tool for taking roughing ceramic cutting toolis capable of machining cuts and for general all-round machine work.

( MACHINERY REPAIRMAN 3 & 2

Lath Tool holdorStralght Shank

Cutter litNot Ground Guitar litGround to Form

A Loft-Hand Round-No.11 R ght -H@nd Lott-Hand Turning ToolTurning ToolTurning Tool Frieling ToolTh riod gR Ight-handCut-Off Tool Faoing Tool Tool

L. N. Turn i R. M. Tool (A)(ng Turn ing Tool(0)

11111 /////M/AP.,

28.66 Flours 6.16. Laths tools and theirapplication. Chapter 6OFFHAND GRINDING OF TOOLS

LEFT-HAND FACING TOOL.This tool is must ,ako consider the type of toolholder and intended for facing on the left-hand side of the the po.;tadri of the tool with respect to the axis work, as shown in figure 6-I5D. The direction of of workpiece. The angular offset and the feed is away from the . The cutting angular vertical rise of the tool seat in a standard edge is on the right-hand side of the tool and the lath: toolholder affects the cutting edge angle point of the tool is sharp to permit machining a a,1 end clearance angle of a tool when it is square corner. se: sip for machining. The position of the point o,the tool bit with respect to the axis of the THREADING TOOL.The point of the wLrkpiece, whether higher, lower, or on center, threading tool is ground to a 60° included angle hanges the amount r/i front clearance. for machining V-form screw threads (fig. 6-15E). Usually, the top of the tool is ground flat and Figure 6-16 shows some of the standard there is clearance on both sides of the tool so Loolholders used in lathe work. Notice the angles that it will cut on both sides. which the tool bits set in the various holders. 1"lese angles must be considered with respect to the angles gourd in the tools and the angle that RIGHT-HAND FACING TOOL.This tool 'he toolholder is sec with respect to the axis of is just the oppoSite of the left-hand facing toot thework.Alsonoticethataright-hand and is intended for facing the right end of the koolholder offset to the LEFT and a left-hand work and for machining the right side of .1 toolholder offset to the RIGHT. For most shoulder. (See fig. 6-15F.) machining olerations, a right-hand toolholder i'tt:'zes a 1,,it-hand turning tool and a left-hand SQUARE-NOSED PARTING (CUT-OFF) to(Av 'dera right-hand turning tool. Study TOOL.The principal cutting edge of this tool is figua 5and 6-16carefullytoclearly on the front. (See fig. 6-15G.) Both sides of the undet...iiid this apparent contradiction. (Carbide tool must have sufficient clearance to prevent tippet! cutting tools should be held directly in binding and should be ground slightly narrower thgalpost or in heavy duty holders similar to at the back than at the cutting edge. This tool is thok used on turret lathes.) convenient for machiningnecks,grooves. squaring ccrners, and for cutting off. he contour of a cutting tool is formed by the side cutting edge angle and the end cutting edge angle of the tool. (Parts A through G of fig. BORING TOOL.The boring tool is 6-15illustrate tharecommended contour of ground the same shape as the left-hand tiimag several types of tools.) There are no definite tool so that the ci'tting edge is on the front ide guidelines on either the form or the included of the cutter bit and may be fed in toward the angle of the contour of pointed tool bits. Each headstock.

INTERNAL-THREADING TO0i..The internal-threading (INSIDE-THREALNINIC, tool is the same as the threading tool in figuc o-15E, except that itis usually iuch smaller. Boring and internal-threading tools may require hirer relief aryles when used in small diameter h. s.

TSTRANDITSHANK TURNINO TOOL* GRINDING ENGINE LATIIE

CUTTING TOOLS LEF T - HAND RIGHT-NANO TWIN NO TOOL TUNNINO TOOL Thematerialsbeingmachined andthe machining techniques used limit the angles of a 28,87(28D) tool bit. When winding the angles, however, you Figure 8.10.Standard lathe toolholders.

6-19 MACHINERY REPAIRMAN 3 & 2

machinist usuallyformsthe contour as he 2.Grind the right side of the tool, holding prefers. For roughing cuts, it isrecommended it at the required angle to form the right thattheincluded angle of the contour of side. pointed bits be made as largeas possible and still 3.Grind the radius on the end of the tool. provide clearance on the trailing sideor end A small radius (approximately 1/32inch) is edge.Toolsforthreading,Ewing between preferable, as a large radiusmay cause chatter. centers, and parting hPv,; .,peeific shapesbecause Hold the tool lightly against the wheeland turn of the form of the nirm.1 cut or the setup from side to side to produce the desiredradius. used. 4.Grind the front of the tool to thedesired front clearance angle. STEPS IN GRINDING A TOOL BIT 5.Grind the top of the tool, holding itat The basic steps are similarfor grinding a the required angle to obtain thenecessary side single-edgedtoolbitfor any machine. The rake and back rake. Try not toremove too much. differenceliesinshapes and angles. Usea of the metal in grinding,as the more metal left coolant when grindingtoolbits.Finish the on thetool, the betterit absorbs the heat cutting edge by honing onan oilstone. The basic produced during cutting. steps for grinding a round nose turning tool are 6.Hone the cutting edge all aroundand on illustrated in figure 6-17. A descriptionof each step follows: top with an oilstone untilyou have a keen cutting edge. Use a few drops ofoil on the oilstone when honing. Honing will 1,Grind the left side of the tool, holding not only it improve the cutting quality of thetool, but it at the correct angle against the wheelto form will also produce a better finish thenecessary side clearance. Use the on the work, coarse and the cutting edge of the toolwill stand up grinding wheel to remove most of themetal, and much longer than if it is not honed. thenfinish on thefine The cutting grinding wheel.(If edge should be sharp in order to shearoff the ground on the periphery ofa wheel less than 6 metal instead of tearing it off. inches in diameter, the cuttingedge will be undercut and will not have thecorrect angle.) GRINDING TOOLS FOR ROUGHING Keep the tool cool wiif; grinding. CUTS A single edged cutting tool usedfor roughing cuts (relatively heavy depth ofcut and heavy GRINDING WHEEL feed) can be modifiedslightly and used for GRINDING GRINDING finishing operations. In finishing,lighter feed WHE *Hu L and less depth of cutare normally used to get a smooth surface. To grinda finishing tool from a roughing tool, itis usuallynecessary only to increase the back rake angle,decrease the side rake and side clearance angles,and grind a radius on the point or nose of the tool. Theonly portion of a tool ground in this GRINDING6 manner that will CUTTER WHIIL be cutting is the noseor point. Grinding a larger SIT back rake angle makesa more acute, chisel-type nose or point. Decreasing side rakeand side clearance provides more supportfor the cutting GRINDING WHEEL edge. By increasing the radius CUTTER of the nose of the SIT tool, more of the cutting edgeis in contact with the work during the cut; andthus, by decreasing the feed rate of the tool,you will have a finer 28.85 cut (similar to a scraping) whichensures a good Figure 8.17.GrIndIng and honinga lathe cutter bit. finish.

6.20 Chapter 6OFFHAND GRINDING OF TOOLS

In general machining work, you will find commonly used materials. The angle of side that it is easy to grind a tool which can be used clearance within the tolerance given is basedon for both roughing and finishing. To do thisyou the fact that small angles are necessary whena grind a roughing tool to increase thenose or light feed rateis used and a larger angle is point radius a little more than usual. When you necessary when a higher feed rate is used. The take the finish cut, decrease the feed rate until frontclearanceangleshouldgenerallybe you obtain the required finish. increased in proportion to the increase in the Table 6-2 gives recommended angles of tools diameter of the workpiece. forroughing andfinishingcutsof various materials. The values provided in table 6-2are somewhatarbitrarilyselectedasthemost TURRET LATHE TOOLS appropriate so that you can grinda minimum number of tools for maximum use, with respect The angles of cutting tools for turret lathes to materials commonly machined in the shop. are quite similar to those for engine lathe tool The angles given in table 6-2 and other tables in bits. However, the cutters themselves are usually this chapter are intended as guidelines for the much larger than those used on an engine lathe beginner. As you gain experience, you will find because the turret lathe is designed toremove that you can grind tools that cut efficientlyeven large quantities of metal rapidly. though the angles do not conform exactly to the Therelativemerits,limitations,and angles prescribed. applications, as well as the grinding of carbon In table 6-2 you will note that the front tool steel, high-speed stedi, Stellite, and carbide clearance angles arepractically standard for toolbits have been discussed in relation to

Table 8-2.Angles for Grinding Engine Lathe Tools

Angle (Degrees) Material Operation Back Side Si e End Rake Rake Rell f Relief

Mild steel Roughing 8-10 14-22 5-9 5-9 Finishing 14.22 0 0 5-9

Hard steel and cast Roughing 6-8 12-14 5-9 5-9 iron Finishing 8 -10 0 0 5-9

Brass and bronze Roughing 8 -8 4-10 5-9 5-9 Finishing 14-22 0 0 5-9

Copper and aluminum Roughing 8-10 16-24 5-9 5-9 Finishing 8 16-24 0 5-9

Monel Roughing 4-8 10-14 5-9 5-9 Finishing 14-22 0 0 5-9

28.273

6-21 .17'4 MACHINERY REPAIRMAN 3 & 2 enginelathe tools.Thatinformationis turret lathe cutting tools will be given in chaptr applicable to turret lathe cutters, witha few 10. exceptions which will be discussed here. As carbide tips cannot tolerate bendibut The turret lathe cutter must withstandheavy are otherwise capable of withstandin: heavy cutting pressures; therefore,itscutting edge cutting pressures, the tool anglespresbed for must be well supported. The amountof support them are somewhat different. Table 6lists the depends upon the amount of sideclearance and clearance and rake angles for carbde-tipped side rake, and front clearance andback rake, cutters. Notice that the side and fronclearance given the tool. The clearance andrake angles angles differ only slightly from those'rescribed prescribed in table 6-2 for tool bitsare given in for high-speed steel cutters butthat the rake ranges, but a turret lathe cutter clearanceand angles differ consiierably. Thereductiln in back rake angles must bemore specifically controlled. rake and side rake angles for carbide-tsped tools You must know the exact toolangles and grind provides a bigger included anglefor the cutting the cutter to those angles. Table6-3 lists the edge and, therefore, greater resiance against angles to which high-speed and:.rbon steel bending stress. cutters should be ground for cuttingparticular kinds of metals. Additional Before a carbide tip isgrou d, a clearance information on angle is ground on the shankwi a conventional

Table 6-3.Angles for Grinding Turret Lathe Tools (High Speed and Carbon Sel)

Angle (D grees) Material Side Front Back Side ClearanceClearance Rake Rake Cast Iron Copper 8 8 8 14 Brass, Soft 8 8 10 25 Hard Bronze 8 8 0 0 8 Aluminum 8 8 5 Steels: 8 8 8 18 SAE X1112 Spec. Screw Stock SAE X1315 Screw Stock 8 8 15 20 8 8 15 20 SAE 1020 Carbon Steel 8 8 15 15 SAE 1035 Carbon Steel 8 8 15 15 SAE 1045 Carbon Steel 8 8' 10 12 SAE 1095 High Carbon Steel 8 R 5 10 SAE 2315 Nickel Alloy 8 8 15 15 SAE 2335 Nickel Alloy (Annealed) 8 SAE 2350 NickelSteel (Annealed) 8 15 15 8 8 SAE 3115 Nickel-ChromiumAlloy 10 12 SAE 3140 Nickel-Chromium 8 8 15 15 (Annealed) 8 SAE 3250 Nickel-Chromium 8 10 12 (Annealed) 8 SAE4140 8 8 12 Chromium-Molybdenum 8 SAE 4615 Nickel-Molybdenum 8 10 12 SAE 6145 Chromium- 8 8 15 15 "inadium 8 8 8 12

28.274 1 75 6-22 Chapter 6OFFHAND GRINDING OF TOOLS

Table 6.4.Angles for Grinding Turret Lathe Tools (Carbide)

Angle (Degrees) Material Side Front LBack Side ClearanceClearance Rake Rake

Cast Iron 4-6 4-6 0-4 10-12

Aluminum 8 -10 8-10 25 15

Copper 8 -10 8 -10 4 20

Brass 6 6 0 4

Bronze 6 6 0 4

Lowcarbon steel up to0.20%carbon 8 -10 8 -10 4-6 10-12

Carbon steel up to0.60%carbon 8-10 8-10 4-6 10-12

Toolsteel over0.60%carbon, and tough alloys 8 -10 8-10 4-6 6-10

NOTE: Keep back rake angle as small as possible for greateststrength.

28.276 grinding wheel. This clearance angle must be other factors are involved, chip control will be slightly larger than the angle to be groundon the discussed after the setting of cutters have been carbide tip. The clearance prevents loading the taken up in chapter 10. grinding wheel with the soft material of the shank when the clearance angles are groundon the tip. SHAPER AND PLANER TOOLS

Stellite cutters should be given tool angles Shaper and planer cutting tools are similar in that lie approximately midway between those shape to lathe tools but differ mainly in the prescribedforthehigh-speedsteeland relief angles. As these cutting tools are held carbide-tipped types. practically square with the work and do not feed during the cut, relief angles are much less than Anotherproblem inconnectionwith thoserequiredforturningoperations. grinding turret lathe cutters is that of providing Nomenclature used for shaper and planer tools is thecutter directional controlforitschips, the same asthat for lathetools; and the especially when the cutter is to machinea tough elements of the tool, such as relief and rake ductile me. al from which the chip peels off ina angles, are in the same relative position as shown continuotis stream. A long, hot chip, in addition in figure 6-13. Both carbon and high-speed steel to being Ardous to you, will often interfere ate used for these tools. with the lope, ltion of the other cuttersor with the operation(ifthe latheitself unless the Several types of tools are required for the direction of its ,un-off is controlled. Assome various operations that may be performedon

6-23 17 Ei MACHINERY REPAIRMAN 3 & 2

the shaper or planer. Althoughthe types differ considerably as to shape, thesame general rules govern the grinding of each type. Handforging of shaper and planer tools isa thing of the past. Toolholders and interchangeable rowel tool bits have A. ROUGHING S. OOWNCUTTING TOOLS C. SHOVEL NOSE replacedforgedtools;thispractice greatly TOOL (RIGHT-AND LEFT -HANG) TOOL reduces the amount of tool steelrequired for each tool. For an efficient cuttingtool, the side and end of the tool must be alaa, Ye dp11.41,Aile,//. ground to give a 0. SIDE TOOLS E. CUTTING- F. SQUARING projecting cutting edge; thisis called side and (RIGHT-AND LEFT-HAND) OFF TOCL TOOL end relief. If the clearance isinsufficient, the toolbit will rub the work, causingexcessive heat and producing a roughsurface on the work. If too much relief is given thetool, the cutting edge will be weak and tendto break during the cut. The front and side clearance 0. ANGLE CUTTING TOOLS H. SHEAR I. GOOSENECK angles seldom t RIGHT- AND LEFT-HAW exceed 3° to 5°. TOOL TOOL In addition to having therelief angles, the tool bit must slope away from thecutting edge. This slope is knowas side rake and reduces the 28.88 Figure 8-Ie.Standard shaper and planertools. power required to force the cutting edgeinto the work. The side rake angleis usually 10° or more, depending upon the type of tool andthe SHOVEL NOSE TOOL (fig. metal being machined. Roughing 6-18C): This tools are given tool may be used for downcuttingin either a no back rake althoughasmall amount is right- or left-hand direction. A small generally required for finishing amount of operations. back rake is required, and thecutting edge is The shape and made the widest part of the tool.The corners use of various standard are slightly rounded to give them longer life. cutting tools are illustrated infigure 6-18 and may be outlined as follows: SIDE TOOL (fig. 6-18D): Bothright- and ROUGHING TOOL (fig. 6-18A):This tool is left-hand side tools sec required forfinishing very efficient for general use and is designedto vertical cuts. These toolsmay also be used for take heavy cuts incastIron orsteel. The cutting or finishing small horizontalshoulders roughing tool is generally groundfor left-hand after a vertical cut has been madein order to, operation as illustrated; for specialapplications, avoid changing tools. the angles may be reversed forright-hand cuts. No back rake is given this tool althoughthe side rake may be as much CUTTING-OFF TOOL (fig. 6.18E):This as 20° for soft metals. tool is given relief on both sidesto allow free Finishing operationson small flat pieces may be cutting action as the depth of cut is performed with the roughingtool if a fine feed increased. is used. SQUARING TOOL (fig. 6.18F): Thistool is DOWNCUTTING TOOL (fig. 6.18B):The similar to the cutting-off tooland may br made downcutting tool may be groundand set for in any desired width. Thesquaring tool is used either right- or left-hand operationand is used chiefly for finishing 'le bot om and sides of for making vertical cutson edges, sides, and shoulder cuts, keyways, aqgrooves. ends. The tool is substantially thesame as the roughing tool described, withthe except on of its position in the toolholder. ANGLE CUTTING TOOL (fig.6-18G): The anglecutting toolis adapted forfinishing -24 Chapter 6OFFHAND GRINDING OF TOOLS operations and is generally used followinga can accurately grind these tools that you will roughing operation made with the downcutting often use in your work. tool. The tool may be ground for either right-or left-hand operation. WHEEL CARE AND STORAGE SHEAR TOOL (fig.6-18H): This tool ois used to produce a high finish on steel and should Allgrindingwheels can be broken or be operated with a fine feed. The cutting edge is damaged due to mishandling and improper ground to form a radius of 3 to 4 inches, twisted storage. Whenever you handle grinding wheels, to a 20° to 30° angle, and given a back rake in take care not to drop themor bump them the form of a small radius. against other hard objects such as the grinderor other wheels. GOOSENECK TOOL (fig. 6-181): This tool Grinding wheels should be stored ina is used for finishing cast iron and must be forged cabinet or on shelves large enough to allow so that the cutting edge is behind the backside selection of a wheel without disturbing the other wheels. of the tool shank. This feature allows the toolto Thestoragespaceshouldproyide spring away from the work slightly, reducing the protection against high humidity, contact 'With tendency for gouging or chattering. The cutting liquids,freezingtemperatures, and extreme edge is rounded at the corners and givena small temperature changes. Also, provisions must be amount of back rake. made to secure grinding wheels aboard shipto prevent them from being damaged when the,ship. is at sea. Thin cutoff wheels should be stacked_,: flat on a rigid surface withoutany separators or GRINDING HANDTOOLS AND DRILLS blotters between them.Flaring cup wheels should be stackedflat with the small ends Tools and Their Uses, NAVPERS 10085-B, together. All other types of wheelsmay be containsdetaileddescriptionsofoffhand stored upright on their rims with blotters placed grinding of twist drills and handtools. Therefore, between them. A sheet metal cabinet, lined with thesesubjects are not discussed here. You felt or corrugated cardboard to prevent wheel should study NAVPERS 10085-Bso that you chipping, is acceptable for storage. CHAPTER 7

LATHES AND ATTACHMENTS

There are several types of lathes installed in the size is determined by two measurements: shipboard machine shops including the engine ( la) either the diameter of work it will swing lathe,horizontalturretlathe,verticalturret over the bed or (lb) the diameter of work 't will lathe, and several variations of the basic engine swing over the cross-slide and (2a) eithe lathe, such as bench, toolroom, and gap lathes. length of the bed or (2b) the maximum d' .a All lathes. except the vertical turret type, have between centers. For example, using meth, is one thing in common for all usual machining and 2a, a 14-inch X 6-foot lathe has a bed is operations.- -the workpiece is held and rotated 6 feet long and will swing work (over the bed) around a horizontal axis while being formed to up to 14 inches in diameter. size and shape by a cutting tool. In a vertical turret lathe, the workpiece is rotated around a Engine lathes range in size front small bench vertical axis. lathes with a swing of 9 inches to very large ' lathes for turning work of large diameters, such Alt of the lathes mentioned above, as well as as low-pressure turbine rotors. A 16-inch swing many of their attachments, are described in this lathe is a good, average size for general purposes andthe nextthreechapters.Engine lathe and isusually,the size installed in ships that have operations and turret lathes and their operations only cne lathe. are cavered later in this manual. To learn the operation of a lathe, you must be familiar with the names and functions of the ENGINE LATHE principal parts. In studying the principal parts in detail, remember that lathes all provide the same An engine 1 he similar to the one shown in general functions even though the design may figure 7-1 is faund in every machine shop. It is differ among manufacturers. As you read the used mainly for turning, boring, facing, and description of each part, find its location on the screw cutting,butit may also be used for lathe pictured in figure 7-1. For specific details drilling, reaming, knurling, grinding, spinning, on a given lathe, refer to the manufacturer's and spring winding. The work held, in an engine technical manual for that machine. lathe can be rotated at any one of a number of differentspeeds.Thecuttingtoolcanbe accurately controlled by hand or power for BED AND WAYS longitudinal feed and crossfeed. (Longitudinal feed is the movement of the cutting tool parallel The bed is the base for the working parts of totheaxisof thelathe; crossfeedisthe the lathe. The main feature of the bed is the movement of the cutting tool perpendicular to ways which are formed on its upper surface and the axis of the lathe.) run the full length of the bed. The tailstock and carriage slide on the ways in alignment with the Lathe size is determined by various methods headstock. The headstock is permanently bolted depending upon the manufacturer. Generally, at one end (at operator's left).

7-1 179 MACHINERY REPAIRMAN 3 & 2

1. Headstock spindle 17. Spindle control lever 2. Identification plate 18. Leadscrew reverse lever 3. Spindle speed index plate 19. Reverse rod stop dog 4. Headstock spindle speed change 20. Control rod levers 21. Feed rod 5. Upper compound lever 22. Lead screw 6. Lower compound lever 23. Reverse rod 7. Tumbler lever 24. Toilstack setover screw 8. Feed-thread index plate 25. Tailstock hondwheel 9. Feed-thread lever 26. Toilstock clamping lever 10. Spindle control lever 27. Tailstock spindle binder lever 11.Electrical switch grouping 28. Tailstock spindle 12. Apron hondwheel 29. Chasing dial 13. Longitudinal Friction lever 30. Carriage binder clamp 14. Cross-feed friction lever 31. Compound rest dial and handle 15. Feed directioaal control lever 32. Thread chasing stop 16. Half nut closure lever 33. Cross-feed dial and handle

28.69X Figure 7-1.-Gear-head engine lathe. 100 7-2 Chapter 7LATHES AND ATTACHMENTS

Figure 7-2 shows the ways of a typical lathe. absolute necessity if accurate lathe work is to be The inset shows the inverted V-shaped ways ( I, done. Some lathe beds have two V-ways and two 3, and 4) and the flat way (2). The ways are flat ways, while others have four V-ways. accurately machined parallel to the axis of the spindle and to each other. The V-ways are guides For satisfactory performance of a lathe, the that allow the carriage and tailstock to move ways must bekeptingoodcondition. A over them only in their longitudinal direction. common fault of careless machinists is to use the The flat way, number 2, takes most of the bed as an anvil for driving arbors or as a shelf for downward thrust. The carriage slides on the hammers, wrenches, and chucks. Never allow outboard V-ways (1 and 4), which, because they anything to strike a'hard blow on the ways or are parallel to number 3, keep it in alignment damage their finished surfaces in any way. Keep with the headstock and tailstock at all timesan them clean and free of chips. Wipe them off

Rj

28.70X Figure 7-2.Rear view of lathe.

7-3 1 J*-1 MACHINERY REPAIRMAN 3& 2

28.72X Figure 7-3.Sliding gear typeheadstock.

daily with an oiledrag to Ole 1p preserve 'heir polished surface. gears. This headstock is similar toan automobile transmission except that it hasmore gear-shift combinations HEADSTOCK andthereforehasagreater number of speed changes. Aspeed index plate, attached to the headstock,indicates the lever, The headstock carries theheadstock spindle positions for the different spindle andthe mechanismfor drivingit.In speeds. Figure the 7-4 shows this plate forthe geared headstock in belt-driven type the drivingmechanism consists Merely of a cone pulley thatdrives the spindle directly or through backgears. When the spindle is driven directly, itrotates with the cone pulley; when the spindle is driventhrough the back gears,itrotates more slowly than thecone pulley, which in this inleaula else turns freely on the Kin, spindle. Thus two speedsarc, available with each position of the belt Wyo. N$ on the cone; if the cone OKINo. pulley has four steps, eightspindle speeds are o.00 Or

The geared headstock shownin figure 7-3 is moreco wlicatedbut more convenientto )perate because speed is changedby shifting 28.73X 7.4. Speed index plate.

7-4 1 Chapter 7LATHES AND ATTACHMENTS figure 7-3. Always stop the lathe when you shift chuck at the nose. The chuck end of the spindle gears to avoid possible damage to gear teeth. (5) is bored to a Morse taper to receive the LIVE Figure 7-3 shows the interior of a typical center. The hollow spindle also permits the use geared headstock that has 16 different spindle of the draw-in collet chuck which is discussed speeds. The driving pulley at the left is driven at later in this chapter. At the other end of the a ;;thistant speed by a motor located under the spindleisthe gear (2) by which the spindle headstock. Various combinations of gears in the drives the feed and screw-cutting mechanism headstock transmit the i ,wer from the drive tirough a gear train locateu on the left end of shaft to the spindle throug,., an intermediate the lathe. A collar (3) is used to adjust end play shaft. Use the speed-change levers to shift the of the spindle. sliding gears on the drive shaft and intermediate shafttolineupthegearsindifferent The spindleissubjectedto considerable combinations. This produces the gear ratios you torque because it drives the work against the need to obtain the various spindle speeds. Note resistance of the cutting tool as well as drives the that the back gear lever has a high and low speed carriage that feeds the tool into the work. For for each combination of the other gears (figure this reason adequate lubrication and accurately 7-4). adjustedbearingsareabsolutelynecessary. (Bearing adjustment should be done only by an The headstock casing isfilled with oil to experienced lathe repairman.) lubricate the gears and the shifting mechanism contained within it. Parts not immersed in the TAILSTOCK oil are lubricated by either the splash produced by the revolving gears or by an oil pump. Be sure The primary purpose of the tailstock (fig. to keep the oil to the oil level indicated on the 7-6) is to hold the DEAD center to support one oil gage, and drain and replace the oil when it endof workbeingmachined oncenters. becomes dirty or gummy. However, it can alt,be used to hold tapered The headstock spindle (fig. 7-5) is the main shankdrills,reamers, anddrillchucks. The rotating element of the lathe and is direct, tailstock moves on the ways along the length of connected to the work which revolves with it. the bedto accommodate work of varying .The spindle is suppoited in bearings (4) at each lengths.Itcanbe clamped in the desired 2nd of the headstock through which it projects. position by the tailstock clamping nut (13). The section of the spindle between the bearings carries the pulleys or gears that turn the spindle. The dead center (11) is held in a tapered The nose of the spindle hol.1s the driving plate, hole (bored to a Morse taper) in the tailstock the faceplate, or a chuck. The spindle is hollow spindle (6). To move the spindle back and forth throughout its length so that bars or rods can be inthetailstockbarrelforlongitudinal passed through it from the left (1) and held in a adjustment, turn the handwheel (9) which turns the spindle-adjusting screw (7) in a tapped hole in the spindle at (8). The spindle is kept from revolving by a key (4) that fits a spline, or keyway, (5) cut along the bottom of the spindle as shown. After making the final adjustment, use the binding clamp (10) to lock the spindle in place. The tailstock body is made in two parts. The bottom, or base (1), is fitted to the ways; the top (2) can move laterally on its base. The lateral movement can be closely adjusted by setscrews. Zero marks inscribed on the base and 28.74X top indicate the center position and provide a Figure 7-5.Cross section .1f a belt-driven headstock. way tomeasuresetoverfortaper turning.

7-5 MACHINERY REPAIRMAN 3 & 2

.&D, 7/r / 3-77VICXX gr \'\'. \;\.\%\'NZNW111.K.I

/), 4 A

sz, Nk.

1.Tailstock base. Handwheel. 2.Tailstock top. lesSpindle binding clomp 3.Tailstock nut. 11.Dead center. 4.Key. 12.End of tailstock screw. 5.Keyway (in spindle). 13.Tailstock clamp nut. 6.Spindle. 14.Tailstock sct-o'er. 7.Tailstock screw. 15.For oiling. 8.Lnternal threads in spindle. 16.Tailstock clamp bolt. 28.75X Figure 7-6.Cross section of a tailstock.

Setover of the tailstock for tape,r turning is cutting too; in the toolpost. The carriageslides described in a later chapter. on the ways along the bed (fig. 7-7). Before you insert a dead centera drj11, cr reamer into the spindle, Figure 7-8 shows a top view of thecarriage. carefully clean the The wings of the H-shaped sadtlIecontain the tapered shank and wipe c ,t the ta,,eredhole of bearing surfaces whichare fitted to the V-ways the spindle. After yc, ;ut a drill or a reamer of the bed. The c_osspiece is machined into the tapered hok .if the spindle, be to form a sure to dovetail for the crossfeed slide. Thecrossfeed tighten the spindle !-,:4t the will not revolve. If the drill or slide is closely fitted to the dovetailand has a reamer is allowed to tapered gib which fits between thecarriage revolve,itwillscorethe tapered hole and dovetailandthe matching dovetail of the destroy its accuracy. The spindle of the tailstock crossfeedslide."hegit is permitssmall engraved with graduations which helpin adjusti.lents to remove anyi..;Feness between determining the depth of a cut whenyou drill or the two parts. The slide is seat:6y ream. to the crossfeed nut whichmoves b3c;. and when the crossfeed se:v.\ is turned by the CARRIAGE nandle. Lie micrometer dial on the crossfeed han leis graduated to perr,.:it accurate infeee.Depending The carriage carries the crossfeed slide and on the manufacturer of the lathe, the dialmay the compound rest which in turn carriesthe be graduated so that eadi division: :presents a 1

7-6 S 4 Chapter 7LATHES AND ATTACHMENTS

COMPOUND REST CROSS-SLIDE

Figure 7-7.Side view of a carriage mounted on the bed.

to 1 ratio or a 2 to I-atio. The compound rest is mounted oh top of the crossfeed slide.

COOKED SCREW Tl,.artiage has T-slots or 2,,ped holes for CROSSSEED MP clamping work for boring or milling. When the CROSS SECTION AT X4 TO SHOW DOS FOE ATTACHING lat is ;et:inthismanner, the carriage DOVETAIL FOR CROSS-SLIDE AND FOLLOWER ROT MUSS TOR CROW= NUT L. movement feeds the work tcthe cutting tool which is revolveu by the headstock spindle. CARRIAGE CLAMP 93E1T Yo., con 'ock the carriage in any posi;.- the bed 1. / :.1--,1ttening the carriage (Imp sew. Use the clamp screw only when doing such work as facing of cutting-off for which longitudinal feed is not -equired. Normally, keep the carriage clamp in the released 1 osition. Always mrve the carriage by hand to be sure it is free befor, you apply the auto .vatic feed.

APRON The apron is attached to the front of the 28.77X carriage. It contains the mechanism that controls Figure 7-8.Carriage (top view). the movement of the carriage for longitudinal

7-7 1 -4-Li t) MACHINERY REPAIRMAN 3 & 2

feed and thread cutting and controls the lateral and in the location of controllinglevers and movementofthecross-slide.You should knobs. But, they all are designed to perform thoroughly the understand the construction and same functions. The principal difference is in the operation of the apron beforeyou attempt to arrangement of geartrains operate the lathe. fordrivingthe automatic feeds. For example, insome aprons Ingeneral,alathe aproncontainsthe there are two separate gear trains withseparate following mechanical parts: operatingleversforlongitUdinalfeedand crossfeed. In others, both feedsare driven from 1. A longitudinal feed HANDWHEEL for the same driving gearon the feed rod through a moving the carriage by hand along the bed.This common clutch and have a selective lever for handwheel turns a pinion that meshes with a connecting the drive to either longitudinalfeed rack gear secured to the lathe bed. or crossfeed. The apron shown in figure 7-9 is of 2. GEAR TRAINS driven by the feedrod. the latter type. These gear trains transmitpower from the feed ,rod to move the carriage alongtile ways and to FEED ROD move thecross-slideacrossthe ways, thus providingpoweredlongitudinal feedand The feed rod transmits power to theapron crossfeed. to drivethe longitudinal feed and crossfeed 3. FRICTION CLUTCHES operatedby knobs on the apron to mechanisms. The feed rod is driven bythe engage or disengage the spindle through a train ofgears, and the ratio of power-feed mechanism. (Some latheshay.. a its speed to that of the spindlecan be varied by separateclutchforlongitudinal feedand changing gears to produce various rates offeed. crossfeed; others have a single clutch forboth.) The rotating feed rod drivesgears in the apron; NOTE: The power f^edsare usually driven these gears in turn drive the longitudinalfeed through a friction club_ to prevent damage to andcrossfeed gearsif excessive strain mechanisms throughfriction is put on the feed clutches, as explained in the descriptionof the mechanism. If clutches are not provided,there is apron. some form of safety device that operatesto disconnectthefeedrodfromitsdriving Lathes which do not have mechanism. a separate feed rod have a spline in the leadscrew to serve the 4. A selective FEED LEVERor knob for engaging the longitudinal feedor crossfeed as desired. 5. HALF-NUTS thatengage, and disengage the lead screw when the lathe isused to cut threads. They are openedor closed by a lever located on the right side of theapron. The half-nuts fit the thread of the leadscrew which turns in them like a bolt in a nut when theyare clamped over it. The carriage is thenmoved by the thread of the lead screw instead of bythe gearsof theapronfeed mechanisms. (The half-nuts are engaged only when the lathe isused tocutthreads,atwhichtimethefeed mechanism must be disengaged. Aninterlocking device that prevents the half-nuts andthe reed mechanism from engaging at thesame time is usually provided as a safety feature.)

Apronsonlathesmadebydifferent manufacturers differ somewhat in construction 28.79X Figure 7-9.Rear view of a latheapron.

7-8 1,Q G Chapter 7LATHES AND ATTACHMENTS

same purpose. The apron shown in figure 7-9 the lc;ad screwa gear on the end of the spindle belongs,to a lathe of this type and shows clearly meshed with a gear on end of the lead screw, how the worm which drives the feed mechanism as shown in figure 7-10. Let a be point of is driven by the spline in the lead screw. If a contact between the spindle gear A and the separate feed rod were used, it would drive the screw Dear B. As each tooth on gear A passes feed worm in the same manner, that is, by point a, it causes a tooth on B to pass this same means of a spline. The spline permits the worm, point. Suppose gear A has 20 teeth and gear B _which_ is _keyed to it, to_ reely along -its- has 40-- teeth. Then when --A- makes- one com pieta length to conform with the movement of the turn, 20 teeth will have passed point a. Since B carriage apron. has 40 teeth around its rim, only half of them will have passed point a. Gear B has made just LEAD SCREW one-half of a revolution while gear A has made one revolution. In other words, gear B with 40 The lead screw is used for thread cutting. teeth will turn half as fast as gear A with 20 Along its length are accurately cut Acme threads teeth, or their speeds are inversely proportional which engage the threads of the half-nuts in the to their size. This relation may be expressed as apron when half-nuts are clamped over it. When follows: the lead screw turns in the closed half-nuts, the carriage moves along the ways a distance equal rpm of Bnumber of teeth on A to the lead of the thread in each revolution of rpm of A number of teeth on B the 1:ad screw. Since the lead screw is connected to the spindle through a gear train (discussed or laterinthesectiononquick-changegear mechanism), the lead screw rotates with the rpm of lead screw spindle. Therefore, whenever the half-nuts are rpm of spindle engaged,thelongitudinal movement of the carriageis directly controlled by the spindle number of teeth on spindle gear A rotation. The cutting tool is moved a definite number of teeth on screw gear B distance along the work for each revolution that the spindle makes. The ratio of the threads per inch of the thread being cut and the thread of the screw is the same as the ratio of the speeds of the spindle and the lead screw. For example: If the lead screw and spindle turn at the same speed, the number of threads per inch being cut is the same as the number of threads per inch of the lead screw. If the spindle turns twice as fast as the lead screw, tht number of threads being cut is twice the number of threads per inch of the lead screw. You can cut any number of threads by merely changing gears in the connecting gear train to get the desired ratio of spindle and lead screw speeds.

GEARING

First,co nsider thesimplestpossible 28.81X arrangement of gearing between the spindle and Figure 7.10. A simple gear arrangement

7-9 MACHINERY REPAIRMAN 3 & 2

By using this formula,you can change the speed of the screw relativurto that of thespindle by changing the gears to get the ratio desired. In figure 7-10, the ratio is 20:40or 1:2. Any combination of gears that hasa ratio of 1:2, such as 30 and 60 or 35 and 70, willcause the lead screw to turn half as fastas the spindle.

Suppose you want to cut 8 threadsper inch on a lathe that has a lead screw with 6 threads perinch.Thecarriagemustcarrythe thread-cutting tool 1 inch along fib; workwhi' the work makes eight completerevolutions. Since the lead screw has 6 threadsper inch, it must revolve six times in the half-nutsto move the carriage 1 inch. Therefore,you must gear the latheto cause thelead screw to make six revolutionswhilethespindlemakeseight revolutions. In other words, the leadscrew must turn 6/8 or 3/4 as fast as the spindle.Since the speeds will be proportional to the sizeof the gears, you can use any two gears having this ratio, such as 30 and 40, 33 and 44,45 and 60, the smaller of the two goingon the spindle (use the inverse ratio formula). 28.82X By now you should have discoveredthat the Figure 7-11.Idler gear inserted betweena driving gear ratio in threads per inch of thethread to be cut and a driven gear. and the lead screw is identical to theratio of the number of teeth of the changegears. If the spindle gear is smaller than thescrew gear, the B. Suppose that A has 20 teeth. Inmaking one thread cut will be finer (more threadsper inch) complete revolution, all of these, 20teeth will than the lead screw and viceversa. pass a given point a and cause 20 teethon I to pass this same point. If 20 teeth on Ipass point Idler Gears a, an equal number of teeth on I willpass point b where gear B meshes withit. Gear B will be moved the same distanceas it would if it were Itis obviously impracticable to havethe direc' .1 meshed with A;so tae ratio between spindle gear mesh directly with thescrew gear theirspeedsremainsthesame,butthe because, for one thing, thedistance between direction of rotation of B is reversed. Idlergears, them is so great that thegears required would be then, are used for twopurposes: (1) to connect too lame. Therefore,' smaller gears of the desired gears in a gear train and (2) toreverse the ratio are used, and idlergears bridge the gap directionofrotationofa gear-driven between them. You can placeany number of mechanism. idler gears between the drivinggear and the driven gear without changing the originalgear Figure 7-12 is an example of simple gearing ratio. The idler gears allow the leadscrew and used on a change gear lathe. Thegear on the spindle gears to rotateas if 'they were in direct spindle drives the studgear shaft A at a fixed contact. ratio,usually1:1,in which the stud gear revolvesat In figure 7-11, I the same speed as the spindle. is an idler gear inserted Between the spindle and the studare the idler between the driving gear A and thedriven gear gears X and Y mounted on the movablebracket Chapter 7LATHES AND ATTACHMENTS

STUD GEAR

REVERSE LEVER A-

IDLER GEAR

SPACING COLLAR

SCREW GEAR 28.83X Figure 7-12.Simple gearing on a lathe. controlled by the reverse lever. When this lever is Thelatheshowninfigure7-12has inthe down position, both X and Yare permanently mounted spindle and idler gears (X connected in the gear train as shown, and the and Y). To vary the thread cutting gear ratios, stud shaft revolves in a direction opposite to change the stud gear and the screw gear. You that of the spindle; when the lever is raised,gear can determine which gears on your machine X is disengaged from the train, andgear Y is must be changed by reading the lathe's operating meshed directly between the spindle and the instructions. stud, thereby reversing the previous direction of the stud gear and all the gears that follow it. Note in figure 7-13 that the stud shaft A has NOTE: The reverse lever has a neutral position an extension on which is mounted a removable that disconnects the spindle from thegear train. gear called the stud gear. (In comparing the gear

STUD GEAR

REVERSE L LARGE COMPOUND STUD GEAR GEAR SMALL COMPOUND GEAR LARGE COMPOUND IDLER GEAR GEAR

SMALL SCREW COMPOUND scat,d GEAR GEAR GEAR

28.84X Figure 7-13.Compound gearing ona lathe.

7-11 1 .d.)9 MACHINERY REPAIRMAN 3 & 2

traininfig.7-13 with the simple gear train extra gears rotating as one on a common axis are described previously, we can consider the stud installed in the train following the studgear. gear as being 1, ,)unted directly on the spindle, Compounding gears for a lathe usually havea since it always revolves at a fixed ratio with it.) ratio of 2 to 1; they double the ratio that would The screw gear shown is also a removablegear exist if simple gearing were used. mounted on the lead screw at B. Now all that you need to do to change the gear ratio to cut If a 2:1 compound gear is installed in the different threadsisto place gears with the manner showninfigure7-13,thespeed correct- number of teeth on the stud shaft A and transmitted- by--the .studgeartothelarge connect. Change gear lathes are equipped with compound gear is reduced by half when it is an assortment of gears which provide enough retransmitted by the small compoundgear to changes foi all practical purposes. the gears that follow. It amounts to thesame thing as using a stud gear with halfas many A simple rule to follow in determining what teeth. gears to use on stud and screw is: Multiply the desired number of threads per inch and the The advantageof compoundingisbest number of threads per inch in the leadscrew by demonstrated by the following example: the same number; if the products correspondto the number of teeth in any two of the change Suppose a gear ratio of 10 to 1is required to gears at hand, use those gears; if not, use some cut a certain fine thread, and the smallestgear other multiplier that will give products to match you have that will fit the stud has 20 teeth. You the gears available. For example, ifyou want to would need a screw gear with 200 teeth, but cut a screw containing 16 threads per inchon such a gear is far too large. However, by usinga the lathe with a lead screw that has 6 threads-per 2:1 compound gear in themanner illustrated, inch, use 5 for a multiplier: you would need a gear only half as large (100 teeth). 5 X 16 = 80 5X 6=30 Quick-Change Gear Mechanism If gears with 80 teeth and 30 teethare on hand, use the 30-tooth gear as the stud gear and the To do away with the inconvenience and loss 80-tooth gear as the screw gear. Ifyou do not of time involvedin removing and replacing have those gears, try other multipliers untilyou changegears,most modernlathes have a arrive at a combination corresponding togears self-containedchangegearmechanism, available. commonly called the QUICK-CHANGE GEAR BOX. There are a number of types usedon If you cannot get the proper ratio ofgears differentlathesbut they areallsimilar in with the change gears you have at handor the principle. gears would be too small or too large to connect properly or conveniently (as would be thecase if The mechanism consists ofa cone-shaped you were cutting very fine threads), you should groupof changegears. You can use instantly COMPOUNDING. Compoundingmeans connect any single gear in the gear train bya substituting two gears for an intermediategear. sliding tumbler gear controlled bya lever. The Compounding changes the ratio of the gear train cone of gears is keyed to a shaft which drives the by the same ratio that the compoundinggears lead screw (or feed rod) directly or throughan bear to each other. intermediate shaft. Each gear in the cluster hasa different number of teeth and henceproduces a Figure 7-13 shows a compound gear trainon different gear ratio when connected in a change gear lathe. T1. the train. only way it differs from The same thing happensas when the sciew gear the simple gear train (fig. 7-12) is that thetwo inthegeartrainis changed,described

7-12 Chapter 7LATHES AND ATTACHMENTS

previously.Sliding gearsalso produce other position of lever B (right, center, or le changes in the gear train to increase the number drives the lead screw through gear L. of different ratios you can get with the cone of Either the lead screw or the feed rod n be change gears described above. All changes are connected to the final driveshaft of the sba box made by shifting appropriate levers or knobs. An by engaging appropriate gears. The index plate or chart mounted on the gear box box illustrated in figure 7-14 has ncet-d-rdd. indicates the position for placing the levers to Twenty -fourdifferent rratios re get the necessary gear ratio to cut the thread ce provided by thequickshe gear box. e produce the feed desired. lower lever has eight positions (fig. 7-15), eac Figure 7-14 is the rear view of one type of of which places a different gear in the gear train \ gear box, showing the arrangement of gears. The and hence 'produces eight different gear ratios. splined shaft F turns with gear G, which is The three positions of the upper level produce driven by the spindle through the maingear three different gear ratios for each of the 8 train on the end of the lath. Shaft F in turn changes obtained with the lower lever, thus drives shaft H through the tumbler gear T which making 24 combinations in the box alone. You can be engaged with any one of the cluster of candoublethisrangebyusingasliding eight different size gears on shaft H by means of compound gear which provides a high- and the lever C. Shaft H drives shaft J througha low-gear ratio in the main gear train. This gives doubleclutchgear,whichtakesthedrive two ratios for every combination obtainable in through one of three gears, depending on the the box, or 48 combinations in all.

LEAD SCREW

r

C' H

28.85X Figural-litQuick-change gear box (rear view). MACHINERY REPAIRMAN 3 & 2

0

28.87X Figure 7-15.Quick-change gear box.

Figure7-16showshowthesiding indicatediiIthe second column, opposite 16 compotmd gear produces two differentgear (fig. 7-15). ratios 'when it is moved in or out. The widegear With the lathe running, shift the tumble at the bottom corresponds to gear C in figure lever C to position directly under the column in 7-14. which 16 is located; rock it until the gears mesh and the handle plunger latches in the hole INSTRUCTIONS FOR OPERATION.If provided. The lathe 'is now set to cut the desired you are to cut 16 threads per inch, locate the thread if the half-nuts are clampedon the lead number 16 ontileindex plate in the first screw. columnandfourthlineunderSCREW THREADS }PER INCH (fig. 7-15). Adust the ADJUSTING THE GEAR BOX FOR sliding gear knob (fig. 7-16) to the OUT position POWER FEEDS.The index charton the gear as indicated opposite 16 in the first column at box also shows the, various rates ofpower the left (fig. 7-15). (You must stop the lathe to longitudinal feed per spindle revolution thatyou adjust the sliding gear.) Start the lathe and set can get -by using the feed mechanism of the top lever (4 7-14) to tilt:LEFT position as apron. For example, in figure 7-15, note that the- JJ') 7- 14 qt. Chapter 7LATHES ANDATTACHMENTS

provides the correct conversionratio. You can find information on this fromhandbooks for machinists, the equipment technicalmanual, and directcorrespondencewiththe equipment manufacturer.

. SLIDING GEAR r-- O. COMPOUND REST

Thecompoundrestprovidesarigid adjustable mounting for the cuttingtool. The compoundrestassembly has the following principal parts (fig. 7-17): SLIDING GEAR SLIDING GEAR "VIM" POSITION "IN" POSITION 1.The compound rest SWIVEL (2)which can be swung around to any desiredangle and DRIVE SHAFT TO OUKK-CHANGE GEAR 110X clamped in position. It is graduatedover an arc of 90° on each side of itscenter position for ease in setting to the angleyou select. This feature is used in machiningshort, steep tapds such as the angleon bevel gears, valVe disks, and lathe centers. 28.86X Figure 7-16.Showing how thegear ratio is changed by 2. The compound rest TOP,or TOPSLIDE sliding gear. (3), is mounted as shownon the swivel section (2) on a dovetailed side. It ismoved along the slide by the compound rest feedscrew turning in finestlongitudinalfeedis0.0030 inch per nut (4), operated by handle (5), ina manner revolution of spindle, the next finestis 0.0032 similar to the crossfeeddescribed previously. inch, etc. To arrange thegear box for power Thisprovidesforfeedingatanyangle longitudinal feed, select the feedyou wish to use (determined by the angular settingof the swivel and follow the same procedureexplained for section), while the cross-slidefeed provides only cutting screw threads, except thatyou engage for feeding at right anglesto the axis of the the power feed lever insteadof the half-nuts. lathe. The graduated collaron the compound Crossfeeds are not listedon the chart but you rest feed screw reads in thousandthsof an inch candeterminethembymultiplyingthe for fine adjustment inregulating the depth of longitudinal feeds by 0.375,as noted on the cut. index plate.

On a lathe witha separate feed rod, a feed-thread shifting lever locatedat the gear box ATTACHMENTS AND ACCESSORIES (part 9 in fig. 7-1) connects thedrive to the feed rod or lead screw as desired. When the feed rod Accessories are the tools andequipment is engaged, the leadscrew is disengaged and vice usedin. routine lathe machiningoperations. versa. Attachments are special fixtureswhich may be secured to the lathe to extendthe versatility of You can cut metric threadson some lathes the lathe to include taper-cutting, that have an English lead milling, and screw (threads per inch grinding. Some of the machined on it) by transposinga set of gears in common accessories and attachments used on lathesare described in the the lead screw to the spindlegear train that following paragraphs.

7-15 1 a3 MACHINERY REPAIRMAN 3 & 2

I

13 14

II 12

0 0

0 SO10SO'...14SO

1.Cross-slide. 6.Crossfeednut. 11.Toolpost-wedge. 2.Compound rest swivel. 7.Chip guard., 3.Compound rest top. 12.Toolpost ring. 8.Swivel securing 13.Toolholder. 4.Compound rest nut. bolts. 5.Compound rest feed 14.Cutting tool. 9.Toolpost. 15.Micrometer collar. - screw handle. 10.Toolpost setscrew.

28.88X Figure 7-17.Compound rest.

TOOLPOSTS unit firmly in place. Various size holes through the toolpost allow the use of assorted diameter Three popular typesstandard, castle, and boring bars. quick change toolposts are discussed in the The quick change type toolpost (fig. 7:19) is following paragraphs. The sole purpose of the available in many Navy machine shipseIt mounts toolpost is to provide a rigid support for the in the T-slots and is tightened in place by the. toolholder. locknut, which clamps the toolpost firmly in The standard toolpost is mounted in the place.Specialtype toolholders are used in T-slot of the compound rest top as shown in conjunction with this type toolpost andare held figure 7-17. A forged tool or a toolholder (13) is in place by a locking plunger which is operated inserted in the slot in the toolpost and restson bythetoolholderlockinghanclle.Some .the toolpost wedge (11) and the toolpost ring toolpostshaveaslidinggibtolockthe (12). By tightening setscrew (10), you clamp the toolholder. With this type toolpost, only the whole unit firmly in place with the tool in the toolholders are changed, allowing the toolpost desired position: to remain firmly in place. The castle type toolpost (fin 7-18) is used with boring bar type toolholdeift mounts in TOOLHOLDERS the T-slot and the toolholder (bo3 bir) passes through the toolpost and the holddovim bolt. By Lathe toolholders are designed to be used tightening the locking nut, you clamp the entire with the various types of toolposts. Only the 194 7-16 Chapter 7LATHES AND ATTACHMENTS

LOCKING NUT

---PINAL----BOIRING BAR TOOLHOLD ER

TOO LPOST

28.299 Figure 7-18.Castle type toolpost and toolholder. three most commonly used typesstandard, size and help to carry the heat generated, by the boring bar, and quick changeare discussed in cutting action away from thepoint of the this chapter. The toolholder holds the cutting cutting tool. tool (toolbit) in a rigid and stable posit an. Standard type toolholders were discussed Toolholdersaregenerally made of a softer briefly in chapter 6 of this manual. However, material than the cutting tool. They are large in therz: are more types (fig. 7-20) than those

LOCKNUT

STRAIGHT SHANK TURNING TOOL

LOCkING HANDLE tt=0 14"2

BORING TOOL - - .

LOCK PLUNGER LEFT HAND RIGHT HAND TURNING TOOL TURNING TOOL STRAIGHT CUT-OFF TOOL

28.300 28.67 Figure 7 -19. Quick change toolpost. Figure 7-20 -St idard-type lathe toolholders.

7-17

.0 T5 MACHINERY REPAIRMAN 3& 2

discussed in chapter 6. Twothat differ slightly from others arethe threading and knurling toolholders. (See fig. 7-21.) DIAMOND STRAIGHT PATTERN \ PATTERN The THREADING TOOLshown in figure 7-21 has a formed cutterwhich needs to be ground on the top surface onlyfor sharpening, the thread form beingaccurately shaped over a large arc of the tool. As the surfaceis worn away by grinding, youcan rotate the cutter to the correct cutting position andsecure it there by the setscrew. NOTE: Thethreading tool is not commonly used. It is customaryto use a regular tootholder with an ordinarytool bit ground to the form of the thread desired. A KNURLING TOOL (fig.7-21) carries pattern on the work by being fed intothe work as it revolves. The purpose of knurlingis to give COARSE MEDIUM a roughened surface on round metalparts like FINE COARSE MEDIUM FINE knobs, to givea better grip for handling. The knurled roll comes ina wide variety of patterns. (See fig. 7-22.)

The BORING BAR typetoolholderis nothing more than a piece of roundstock with a screw-on cap. (Seefig. 7-18.) The capsare KNURLING PRODUCED BY KNURLING PRODUCED BY available with square holesbroached through PAIRS OF RIGHT AND PAIRS OF STRAIGHT them at various angles (fig. 7-18)and sizes. LEFT-HAND STANDARD LINE KNURLS FACE KNURLS

28.301 Figure 7-22.Types of knurling rolls.

When the proper size toolbitis inserted into the cap and the cap is screwedon to the threaded end of the piece of round stock,the entire unit becomes a very rigid boring toolwhich is used in KNURLING TOOL. conjunction with the castle typetoolpost. The QUICK CHANGEtype toolholder (fig. 7-23) is mountedon the toolpost by sliding it from above and downwardover the dovetails. This toolholder hasa height adjusting ring to allow you to set theproper height prior to a locking it in place. The quickchange toolholder comes in a wide range of styles. Afew of these styles are shown in figure 7-24. THREADING TOOL LATHE CHUCKS

28.67X The lathe chuck is a device Figure 7-21.Knurling and threading for holding lathe tools. work. It is mountedon the nose of the spindle.

7-18 Chapter 7LATHES AND ATTACHMENTS

28.302 28.304 Figure 7 -23. Quick change toolpost and toolholder. Figure 7-25.Four-jaw independent chuck.

The work is held by jaws whichcan be moved in There are several different styles of jaws for radial slots toward the center to clampdown on 4-jaw chucks. You canremove some of the the sides of the work. These jawsare moved in chuck jaws by turning the adjusting and out by screws turned by screw and a chuck wrench then re-inserting them in the oppositedirection. applied to the sockets located at the outerends Some chucks have two sets of jaws, of the slots. one set being the reverse of the other. Another stylehas The 4-JAW INDEPENDENT lathe chuck, jaws thatarebolted onto a slide by two figure 7-25, is the most practicalfor general socket-head bolts. On this styleyou can reverse work. The four jaws are adjustedone at a time, the jaws by removing the bolts, reversing making it the possibleto hold work of N arious jaws and re-inserting the bolts. Youcan make shapes and to adjust the center of the workto special jaws for this style chuck in the shop and coincide with the axial center of the spindle. machine them to fit a particular size ODor ID. The 3-JAW UNIVERSALor scroll chuck (fig. 7-26) can be used only for holdinground or hexagonal work. All three jawsmove in and out ;etherinoneoperation.Theymove, multaneously to bring the workon center This chuck is easier to operate .:anthe four-jaw type, but when itsparts become worn you cannot relyon its accuracy in centering. Proper lubrication and constantcare in use are necessary toensure reliability. The same styles of jaws available for the 4-jaw chuck are also available for the 3-jaw.

!PARTING' COMBINATION CHUCKS areumvtrsal chucks having independent movementof each jaw in addition to the universalmovement. 28.303 Figures7-3 and 7-5illustratethe usual Figure 7-24.Quick change toolholder. meansprovidedforattachingchucks and

7-19 1 7 MACHINERY REPAIRMAN 3 & 2

28.91X Figure 7-27.Draw-in collet chuck assembled.

results are obtained when the diameterof the 28.305 work is exactly the same sizeas the dimension Figure 7-26.Three-jaw universal chuck. stamped on the collet.

To ensure accuracy of the work whenusing faceplates to lathes. The taperednose spindle thedraw-incollet chuck, be sure that (fig. 7-3) is usually found the. on lathes that have a c,.ntact surfaces of the collet and closingsleeve swing greater than 12 inches. Matchinginternal are free of chips and dirt. NOTE: The standard tapers and keyways in chucks for these lathes collet has a round hole, but special colletsfor ensure accurate alignment and radial locking. A square and hexagonal shapes are obtainable. free turning, internally threaded collaron the spindle screws on a boss on the back' of the The RUBBER COLLET CHUCK (fig.7-28) chuck to secure the chuck to the spindlenose. is designed to hold.any bar stock from1/16 inch On small lathes, chucksare screwed directly on up to 1 3/8 inch. It is different from the draw-in the threaded spindle nose. (See fig. 7-5.) type collet previously mentioned in that the bar The DRAW-IN COLLET chuck is usedto stock does not have to be exact in size. hold small work for machining in the lathe.It is the most accurate type of chuck madeand is The rubber flex collet consists of rubberand intended for precision work. hardened steel plates. Thenose of the chuck has external threads, and, by rotating the handwheel Figure 7-27 shows the parts assembledin (fig. 7-28), you compress the colletaround the place in the lathe spindle. The collet chuck bar. This exerts equal pressure from allsides and which holds the work is a split-cylinder with an permits you to make very accuratealignment of outside taper that fits into the tape:ed closing the stock. The locking ring, when sleeve and screws into the threaded end pressed in, of the gives a safe lock that prevents the colletfrom hollow drawbar. When the handwheel isturned coming loose when the machine is inoperation. clockwise, the collet is pulled into thetapered sleeve, thereby decreasing the diameter ofthe DRILL CHUCKS are used to holdcenter hole in the collet. As the collet is closedaround drills,straight shank drills, reamers,taps, or the work, the work is centered accuratelyand is small rods. The drill chuck is mounted held firmly by the chuck. on a tapered shank or arbor which fitsthe Morse taper hole in the headstock or tailstock spindle. are made with hole sizes ranging Figure7-29 shows thethree-jawtype. A from 1/64 inch up, in 1/64-inchsteps. The best revolving sleeve operated bya key opens or

7-20 1 US Chapter 7LATHES AND ATTACHMENTS

410

NOSE

LOCKING RING

TIGHTENING HANOWHEEL

7/8"-1" cot.LET,

1/16"-1/13" COLLET 28.92X Figure 7-29.Drill chuck. 28.306 Figure 7-28.Rubber flex collet chuck. points so it can be turned accuratelyon its axis. The headstock spindle center is called the LIVE closes the three jaws simultaneously to clamp center because it revolves with the work. The and center the drill in the chuck. tailstockcenteriscalledthe DEAD center FACEPLATES are used for holding work of ':,.cause it does not turn. Both live and dead such shape and dimensions that itcannot be centers have shanks turned to a Morse taper to swung on centers or in a chuck. The T-slots and fit the tapered holes in the spindles; both have other openings on the surface of the faceplate points finished to an angle of 60°. They differ provide convenient anchor points for bolts and only in that the dead center is hardenedand clamps used in securing the work to it. The tempered to resist the wearing effect of the faceplate is mounted on thenose of the spindle. work revolving on it. The live center revolves The DRIVING PLATE is similar toa small faceplate and is used primarily for driving work thatis held between centers. A radialslot W POWs receives the bent tail of a clampedto the work and thereby transmits rotary motion TAPERED SHANK (MORSE TAPER)r TAPERED SHANK (MORSE TAPER) to the work.

LATHE CENTERS UVE WITER DEAD CENTER

Thelathe centers shown infigure 7-30 28.93 provide a means for holding the work between Figure 7-30.Lathe centers.

,7-21 1 t,,9 MACHINERY REPAIRMAN 3 &2 with the work, and it is usually left soft. The machined on centers because thefrictional dead center and live centermust NEVER be contact alone between the live interchanged. A dead center requires center and the a lubricant work is not sufficient to drive thework. between it and the center hole to preventseizing and burning of the center. NOTE: There is a The common lathe dog shownat left in groove aroundthe hardenedtail center to figure 7-32 is used for round work distinguish it from the live center. or work that has a regular section (square, hexagon,octagon). The centers fit snugly in the taperedholes of The piece to be turned is heldfirmly in hole A the headstock and tailstock spindles.If chips, by setscrew B. The bent tail C projectsthrough a dirt,orburrs prevent a perfectfitinthe slot or hole in the driving plateor faceplate, so spindles, the centers will notrun true. that when thefaceplaterevolves with the spindle, it also turns the work. Theclamp dog To remove the headstockcenter, insert a illustrated at the right in figure 7-32 brass rod through the spindlehole and tap the may be center to jar it loose; you used for rectangular or irregularshaped work. can then pick it out Such work is clamped betweenthe jaws. with your hand. Toremove the tailstock center, run the spindle back as far as it willgo by. turning the handwheel to the left.When the end CENTER REST of the tailstock screw bumpsthe back of the center, it will force it out of the taperedhole. (See fig. 7-6.) For machining hollow cylinders, The center rest, also called the steadyrest, is such as pipe, used for the followingpurposes: use a bull-nosed center called a PIPE CENTER. Figure 7-31 shows its construction. The taper 1.To provide an intermediatesupport or shank A fits into the headand tail spindles in rest the same manner forlongslender bars or shafts being asthe lathe centers. The machined between centers. It conical disk B revolves freelyon the collared prevents them end.Differentsizedisksaresuppliedto accommodate various ranges of pipesizes. Ballbearing or nonfriction centerscontain bearings that allow the pointof the center to rotatewith the workpiece while theshank remains stationary in the tailstockspindle. The center hole does not needa lubricant when this type of center is used. A LATHE DOGS

2 Lathe dogs are used in conjunctionwith a driving plate or faceplateto drive work being A

28.94 Figure 7-31.Pipe center. 28.95X Figure 7-32.Lathe dogs.

_ 7-22 0 Chapter 7LATHES AND ATTACHMENTS

from springing under cut or saggingas a result of their otherwise unsupported weight.

2. To support and provide a center bearing for one end of work, suchas a spindle, being bored or drilled from the end when it istoo long to be supported by the chuck alone. Thecenter rest, kept aligned by the ways,can be clamped atanydesiredpositionalongthebed,as illustrated in figure 7-33. It is importantthat the jaws A be carefully adjusted to allowthe work B to turn,freely and at the same time keepit accurately centered on the axis of the lathe.The top half of the frame is hinged at Cto make it easier to place in position withoutremoving the work from the centersor changing the position of the jaws.

FOLLOWER REST

The follower rest is used to back 28.97X up work of Figure 7-34.Follower rest. small diameter to keep it from springingunder the stress of cutting. This rest gets itsname because it follows the cutting toolalong the TAPER ATTACHMENT work. As shown in figure 7-34, it isattached directly to the saddle by bolts B. The adjustable The taper attachment, illustrated in figure jaws bear directly on the finisheddiameter of 7-35, is used for timing and boring the work opposite and above the cutting tapers. It is tool. bolted to the back of the carriagesaddle. In operation, it is connected to the cross-slideso that it moves the cross-slide laterallyas the

-

28.96X 28.98X Figure 7-33.Center rest. Figure 7-35.A taper attachment.

7-23 2 u MACHINERY REPAIRMAN 3 & 2 carriage moves longitudinally, therebycausing the cutting tool to move at The threading dial consists ofa worm wheel an angle to the axis which is attached to the lower end of of the work to producea taper. a shaft and meshed with the lead screw. The dial islocated The angle of the desired taper isset on the on the upper end of the shaft. As the leadscrew guide bar of the attachment,and the guide bar revolves, the dial turns. The graduationson the support is clamped to the lathe bed. dial indicate points at which the half-nutsmay Since the cross-slide is connectedto a shoe be engaged. When the threading dial isnot being that slides on this guide bar, the toolfollows used disengage it from the leadscrew to prevent along a line that is parallel to theguide bar and unnecessary wear to the worm wheel. hence at an angle to the work axiscorresponding to the desired taper. CARRIAGE STOP The operation and application of thetaper attachment will be further explainedunder the You can attach the carriage stop to the bed subject of taper turning in chapter 10. at any point where you want tostop the carriage. The carriage stop is used principallyin THREAD DIAL INDICATOR turning,facing, or boring duplicate parts; it eliminates the need for repeatedmeasurements The thread dial indicator, shown in figure of the same dimension. In operation,set the 7-36, lets you quickly return thecarriage to the stop at the point where you want to stopthe beginning of the thread to setup successive cuts. feed. Just before the carriage reachesthis point, This eliminates the necessity ofreversing the shut off the automatic feed andcarefully run lathe and waiting for the carriageto follow the the carriage up against the stop. thread back to its beginning. The dial,which is Carriage stops are provided withor without geared to the lead screw, indicateswhen to micrometer adjustment. Figure 7-37shows a clamp the half-nuts on the leadscrew for the micrometer carriage stop. Clamp iton the ways next cut. in the approximate position requiredand then adjust it to the exact setting bymeans of a micrometer adjustment. NOTE: Do not confuse

28.99X 28.100X Figure 7-36.Thread dial indicator. Figure 7-37.Micrometer carriage stop.

7-24 Chapter 7LATHES AND ATTACHMENTS

this stop with the automatic carriagestop that automatically stops the carriage bydisengaging the feed or stopping the lathe.

GRINDING ATTACHMENT

The grinding attachment, illustratedin figure 7-38, is a portable grinder witha base that fits on the compound rest in the samemanner as the toolpost.Like the cutting tool, the grinding attachment can be fed to the workat any angle. It is used for grinding hard-facedvalve disks and seats, for grinding lathe centers, and forall kinds of cylindrical grinding. Forinternal grinding, smallwheelsareusedonspecialquills (extensions) screwed on the grinder shaft.

MILLING ATTACHMENT

The milling attachment adapts thelathe to perform milling operationson small work, such ascuttingkeyways,slottingscrewheads, machining flats, and milling dovetails.Figure 7-39 illustrates the setup for 28.102X milling a dovetail. Figure 7-39.Milling attachment. The milling cutter is held inan arbor driven by the lathe spindle. The work isheld in a vise on therefore its movementcan be controlled by the themillingattachment.Themilling longitudinal f.;ed and crossfeed of attachment is mountedon the cross-slide and the lathe. The depth of the cut is regulated bythe longitudinal feed while the length of thecut is regulated by the crossfeed. Vertical motion iscontrolled by the adjusting screw at the top of theattachment. The vise can be set atany angle in a horizontal orverticalplane. A milling attachmentis unnecessaryin shops equipped with milling machines.

TRACING ATTACHMENTS

A tracing attachment fora lathe is useful whenever you have to make severalparts that are identical in design and size. Atracer is a hydraulically actuated attachmentthat carries the cutting tool on a path identicalto the shape and dimensions of a patternor template of the parttobe made. The major parts ofthe attachment are a hydraulicpower unit, a tracer valveto which the stylus that followsthe 28.101X templateisattached,acylinderandslide gure 7-3 .Grinder mounted on compound rest. assembly that holds the cutting F\ tool and moves

2O3 MACHINERY REPAIRMAN 3 & 2

in or out on the command of the tracer valve- hydraulic pressure output, and a templa' assembly that holds the template of thepa. bemade.Thereareseveraldiffc..nt manufacturers of tracers, and each one hasa slightly different design and varying operating features. Tracers can be used for turning, facing, and boring and are capable of maintaininga dimensional tolerance equal to that of the lathe being used. Templates for the tracercan be made from either flat steel or aluminum plateor from round bar stock. It is important that the template be exactly like the finished part you require. Any scratch,dent, or misinachined dimension will be reproduced on the parts to be made.

OTHER TYPES OF LATHES

The type of engine lathe that has been described in this chapter is the general-purpose 28.103X screw cutting precision lathe that is universally Figure 7 -40. A bench lathe. used in the machine shops of ships in the Navy.

Ay

Y. 28.104X Figure 741.A gap lathe. 2 j4 7-26 Chapter 7 LATHES AND ATTACHMENTS

Repair ships also carry other types. A short are sometimes used in the toolroom of repair description of some other types follows. ships.

TOOLROOM LATHEisthename The GAP (EXTENSION) LATHE shown in commonly applied to an engine lathe intended figure 7-41 has a removable bed piece shownon for very accurate work, suchas the manufacture the deck in front of the lathe. This piececan be of small precision instruments and tools. removed from the lathe bed to createa gap into which work of larger diametermay be swung. A BENCH LATHE (fig. 7-40) isa small Some gap lathes are designedso that the ways engine lathe mounted on a bench. Such lathes can be moved longitudir ',1y to create the gap.

7-27 CHAPTER 8

BASIC ENGINE LATHEOPERATIONS

In chapter 7 you became familiar with the 5. Use assistance when handling heavyor basic design and functions of the engine lathe awkward parts, stock, or machine accessories. and the basic attachments used with the engine lathe.Inthischapter, we willdiscuss the 6. Never remove chips withyour bare fundamentals of engine lathe operations. hands; use a stick or brush. (Stop the machine while removing the chips.) 7. Prevent long chips from being caught in PREOPERATIONAL PROCEDURES the chuck by using good chip control procedures on your setup. As a Machinery Repairmanyou will be 8. Disengagethemachinefeedbefore required to know and use specific procedures talking to anyone. that must be followed both prior to and during operation of the engine lathe. First, you must be 9. Know how to stop the machine quickly fully aware of and comply with all machine if an emergency arises. operator safety precautions. Secondly, you must 10. Be, attentive, not only to the operation be familiar with the specific type engine lathe of your machine, but the events goingon around you are going to operate. it. 11. If it is necessary to operatea lathe while WHE SAFETY PRECAUTIONS underway,beespeciallysafety,conscious. (Machines should then be operated only in In machine operations, there is onesequence relatively calm seas.) of events that you must always follow. SAFETY FIRST, ACCURACY SECOND, AND SPEED 12. Be alert to the, location of the cutting LAST. With this in mind, we will discuss the tool whiletaking measurements or making safety of lathe operations first. adjustments to the machine. 13. Alwaysobservethespecificsifety 1. Prepare yourself by rollingup shirt precautions posted for the machineyou are sleeves and removing watches, rings, and other operating. jewelry that might become caught whileyou are operating a machine. MACHINE CHECKOUT 2. Wear safety glasses or a face shield of the approved type atall times when operating a Before attempting, the operation of any lathe or when in the area of lathes thatare in lathe, make sure you know how torun it. Read operation. alloperating instruction's supplied with the 3. Be surethe work areaisclear of machine. Ascertain the location of the various obstructions that you might fall over or tripon. controls and how to operate them. Whenyou 4. Keep the deck area around your machine are satisfied that you know how they work, start clear of oil or grease to prevent the possibility of the motor, but first check to see that the spindle anyone slipping and falling into the machine. clutch and the power feeds are disengaged. Then MACHINERY REPAIRMAN 3 & 2

become familiar with all phasesof operation, as Do not treat your machine roughly. When follows: youshiftgearstochange speed orfeed, remember that you are meshing solid gear teeth; 1. Shift the speed hangelevers into the feed the gears into engagement. Disengage the various combinations; start andstop the spindle clutch and stop the lathe before shiftinggears. aftereachchange.Getthefeedofthis operation. Before engaging the longitudinal feed, be certain that the carriage clamp screw is loose and 2.With the spindle running at its slowest that the carriage can be Moved by hand. Avoid speed, try out the operation of thepower feeds running the carriage against the headstockor and observe their action. Take care not torun tailstockwhileunder power feed;carriage the carriage too near the limits of its travel. pressure against the headstock or the tailstock Learn how' to reverse the direction of feeds and puts an unnecessary strain on the lathe andmay how to disengage them quickly. Before engaging jam the gears. either of the power feeds, operate the hand controls to be sure parts involved are free for Do not neglect the motor just because it ,running. may be out of sight; check its lubrication. If it does not run properly, notify the Electrician's 3.Try out the operation of engagingthe lead screw for thread cutting. Rememberthat Mate whose duty it is to care for motors. He will you must disengage the feed mechanism before cooperate with you to keep it in good condition. the half-nuts can be closedon the lead screw. In a m_achine that has a belt drive from the motor to the lathe, avoid getting oil or greaseon 4.Practicemakingchangeswiththe the belt when oiling the latheor motor. QUICK CHANGE GEAR MECHANISM by referring to the thread and feed index plateon Keep your lathe CLEAN. A clean and the lathe you intend to operate. Remember that orderly machineis an indication of a good changes may be made in the gear box with the mechanic. Dirt and chips on the ways, the lead lathe running slowly, but you must stop the screw, or the crossfeed screws will cause serious lathe for speed changes made by shiftinggears in wear and impair the accuracy of the machine. the main gear train. Never put wrenches, files, or other toolson Maintenanceisanimportantpartof the ways. If you must keep toolson the bed, use operational procedure for lathes and must be a board to protect the finished surfaces of the performedinaccordancewiththeNavy's ways. PlannedMaintenanceSystem(PMS).This subjectis covered indetailin the Military Never use the bed or carriageas an anvil; RequirementsforPettyOfficerstraining remember that the lathe is a precision machine manual. In addition to the regular planned and nothing must be allowed to destroyits maintenance, make it a point to oilyour lathe accuracy. daily where oil holes are provided. Oil theways often, not only for lubrication but to protect their scraped surfaces. Oil the leadscrew often SETTING UP THE LATHE while it is in use to preserve itsaccuracy. A worn lead screw lacks precision in thread cutting. Be Before starting a lathe machining operation, sure the headstock is filled up to the oil level; always ensure that the machine is setup for the drain out and replace the oil when it becomes job you are doing. If the work is mounted dirty or gummy. If your lathe is equipped with between centers, check the alignment of the an automatic oiling system for some parts, be dead center with the live center and makeany sure all those parts are getting oil. Make it a changes required. Ensure that the toolholder and habit to CHECK frequently for lubrication of all cutting tool are set at the proper height and moving parts. angle.Check the workholding accessory to

8-2 2 Chapter 8BASIC MACHINE LATHEOPERATIONS

ensure that the workpiece is held securely. Use ways and theri moving the tailstock laterally the center rest or follower restto support long with two adjusting workpieces. screws. At the rear of the tailstock are two zero lines, and thecenters are approximately aligned when these lines PREPARING THE CENTERS coincide. To check the approximate alignment,move the tailstock up until the centers almosttouch and observe their relative positions 'The first step in preparing the as shown in centers is to figure8-2. To produce veryaccurate work, see that they are accurately mounted in the -especiallyifitislong, headstock and tailstock spindles. The use the following centers procedure to determine and correcterrors in and the tapered holes in which theyare fitted alignment not otherwise detected. must be perfectly clean. Chips and dirtleft On the contact surfaces will impair accuracy by Mount the work to be turned,or a piece of preventing a perfect fit of the bearingsurfaces. stock of similar length, Be sure that there on the centers. With a are no burrs in the tool in the toolpost, takea small cut to a hole.If you findburrs, remove them by depth of a few thousandths of carefully scraping or reaming the an inch at the surface with a headstock end of the work. Thenremove, the Morse taper reamer. Burrs will producethe same work from the centers to allow inaccuracies as chips or dirt. the carriage to berunbacktothetailstockwithout withdrawing the tool. Do not touch Center points must be accurately finished the tool to setting. Replace the work in thecenters, and an included angle of 60°. Figure 8-1 shows the with the tool set at the previous method of checking the angle with depth take a center gage. another cut coming in from thetailstock end. The large notch of the centergage is intended Compare the diameters of these cuts for this particular purpose.. If the with aI. test shows that micrometer. If the diametersare exactly the / the point is not perfect, true thepoint in the lathe by taking a cut same, the centers are in perfect alignment. If over the point with the they are different, the tailstockmust be adjusted compound rest set at 30°. The hardenedtail inthe direction required bymeans of the center must be annealed beforeitcan be machined in this manner; set-over adjusting screws. Repeat the abovetest or it can be ground if a and adjustment untila cut at each end produces grinding attachment is available. equal diameter.

Aligning and Testing You can also check positivealignment of centers by placing a test bar betweencenters and To turn a shaft straight and bringing both ends of the barto a zero reading true between as indicated by a dial indicator clamped inthe centers, be sure the centers are in thesame plane parallel to the ways of the lathe.You can align the centers by releasing the tailstock.from the

HEADSTOCK TAILSTOCK

28.105X Figure 8.1. Checkingcenterpointwith a center 28.106X gage. Figure 8.2. Aligning lathe centers.

8-3 2 US MACHINERYREPAIRMAN 3 & 2

HEADSTOCK CENTER TEST BA' TAILSTOCK CENTER

DIAL INDICATOR

28.107X Figure 8-3.Alignment of lathecenters with a dial indicator.

toolpost(fig. 8-3). The tailstock must be without annealing. As in machining, thefirst clamped to the ways and the test barmust be step after placing the center in the headstock properly adjusted between centersso there is no spindle is to set the compound end play when you take the indicator rest over to 30° readings. with the axis of the lathe. Second,mount a toolpost grinder or grinding attachment Another method you can on the use for positive lathe as shown in figure 8-5. Third,cover the alignment of lathe centers is to takea light cut exposed ways of the lathe with cloth or overthe work held between paper to centers. Then keep the grinding grit out of the bearingsurfaces measuretheworkateachendwitha of the bed and cross-slides. Fourth, micrometer. If the readings differ, adjust put the the headstock in gear to give approximately200 tailstockaL..vrdingly.Repeat theprocedure rpm to the spindle and take a light cut until the centers are aligned. over the center point, feeding the wheelacross the point with the compound rest feed handle. Truing and Grinding Continue to feed the wheel back and forth untilit is cutting evenly all around and the entirelength To machine or truea lathe c,mter, remove the faceplate from the spindle. Theninsert the livecenterintothespindle andsetthe compound rest at an angle of 30° with theaxis of the spindle, as shown in figure8-4. Place a round-nose tool in the toolpost andset the cutting edge of the tool at the exactcenter point of the lathe center. Machinea light cut on the center point and test the point witha center gage. All lathe centers, regardless of size,are finished to an included angle of 60°.

If the tailstock spindle lathecenter is to be trued, anneal it and machine it in theheadstock spindle, following thesame operations described for truing a live center; thenremove, harden, and temper the spindle. It isnow ready for use in the tailstock.

Ifatoolpostgrinderis available,the 28.108X hardened center may be truedby grinding Figure 8 .4. Machining a lathe center.

8-4 2 J;) Chapter 8BASIC MACHINE LATHE OPERATIONS

DIRECTION OF FEED LATHE CENTER 30° PkwfrAti

GRINDING LATHE WHEEL SPINDLE vs*-00 AX IS TOOL POST GRINDER

28.341 28.110X Figure 8-5.Grinding a lathe center. Figure 8-8.Tool overhang.

dP of the center point. Then check the angle witha high-speed steel cutting tool to straight turn center gage. Reset the compound rest if neces- steel, cast iron and other relatively hard metals, sary and cc.ntinue grinding until the center fits set the point about 5° above center. A rule the center gage exactly. Observe theaccuracy of measurement of approximately 3/64 inch times the fit by placing a light beneath the center and thediameterof the workpiece equals5°. looking forlight between the center point Aluminum being cut witta high-speed steel surface and the edge of the center pointgage. cutting tool should b' sctlightly more than 5° Additional information on the operation of above center, while copp...., brass and other soft the toolpost grinderis provided later in this metals require the cutting tool point to be set chapter. exactly on center. The point of cast alloy (ste'lite, etc.), carbide, and ceramic cuttingtools SETTING THE TOOLHOLDER should be placed exactly on center regardless of AND CUTTING TOOL the material being cut. The tool should be placed on center for threading, turningtapers, The first requirement for setting the toolis parting (cutting-off) or boring. to have it rigid. Be sure the tool sets squarely in the toolpost and that the setscrew is tight. The height of the tool in the toolholder Reduce overhang as much as possible to prevent illustratedinfigure 8-6 can be adjusted by tool springing during cutting. If the tool hastoo moving thehalf-moonwedge beneaththe much spring, the point of the tool will catchin toolholderinoroutasrequired.The the work, causing chatter and damaging boththe quick-change type toolholder usually hasan tool and the work. The relative distances of A adjusting screw to stop the tool at thecorrect and B in figure 8-6 show the correct overhang height. Some square turret type toolholders for the tool bit and the holder. Whena quick require a shim beneath the tool to adjust the change type toolholder is used, tool overhang height. should not exceed twice the width of the cutting tool or of the shank whenyou use a carbide There are several methods you canuse to set Insert type cutting tool. a tool on center. A dead center placed in the tailstock can be used to align the point ofthe The point of the tool must be correctly tool with the point of the center. The tailstock positioned on the work. Whenyou are using a spindle on many lathes hasa line on the side

8-5 2u MACHINERY REPAIRMAN 3& 2

that represents the center. Anothermethod is to place a 6-inch rule againstthe workpiece in a vertical position andmove the cross-slide in until the tool lightly touches therule and holds it in place.Look attherule from the side to determine if the height of thetool is correct. The rule will be straightup and down when the tool is exactly on center andwill be at an angle when the tool is either highor low. 28.111 Figure 8-7.Drilling center hole. METHODS OF HOLDINGTHE WORK Centering the Work Accurate work cannot be performedif work isimproperlymounted.Requirementsfor proper mounting are: To center drill round stock suchas drill rod or cold-rolled steel, secure the workto the head spindle in a universal chuck 1. or a draw-in collet The work centerlinemust be accurately chuck. If the work is too long centered along the axis of the lathe and too large to spindle. be passed through the spindle,use a center rest to support one end. It is good shop 2. The work must berigidly held while practice to being turned. first take a light finishing cutacross the face of the end of the stock to becenter drilled. This will ensure a smooth and 3.The work must not besprung out of even surface and will shape by the holding device. reduce the danger of "wandering"or breaking of the center drill. The centering toolis held in a drill chuck in the tailstock spindle 4.The work must be adequately and fed to the supported work by the tailstock handwheel(fig. 8-7). against any sagging caused byits own weight and If a piece must be centered against springing caused bythe action of the very accurately, cutting tool. the tapered center hole shouldbe bored 'after center drilling to correctany run-out of the drill. You can do this by grinding There are four general methodsof holding a tool hit to a work in the lathe: (1) between center gage at a 60° angle.Then, with the centers, (2) on a t *olholderheldinthetoolpost, mandrel, (3) in a chuck, and (4)on,a faceplate. setthe Work may also be clamped compound rest at 30° with the lineof center as to the carriage for shown in figure 8-8. Set the tool boring and milling; the boringbar or milling exactly on the cutteris held and driven by theheadstock spindle. Other methods of holdingwork to suit special conditionsare: (1) one end on the live center orina chuck with the other end supported in a center rest, and (2)one end in a chuck with the other endon the dead center.

HOLDING WORK BETWEENCENTERS tool elt

To machine a workpiecebetween centers, drill center holes in each endto receive the lathe centers. Secure a lathe dogto the workpiece and then mount the work betweenthe live and dead centers of the lathe. 28.112 Figure 8-8.Boring center hole.

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COMBINED DRILL 8 COUNTERSINK

NO.OFCOMB.DRILLDIA.OF WORKLARGE DIAMETER OFDIA. OF DRILL AND COUNTERSINK DIA. OF BODY (W) COUNTERSUNK HOLE(C1 (D) (F) 1 3/16"T05/16" 1/8" 1/16" 13/64" 2 3/8"TO I" I/16" L/32" 3/16" 3 11/4" TO 2" 1/4" .1/8" 5/16" 4 2 I/4" TO 4" 5/16" 5/32" 7/16"

28.113X Figure 84.Correct size of centerholes.

center for height and adjust to theproper angle you must remove the broken part. Sometimes it with the center gageas shown at A. Feed the can be driven out by a chisel or jarred loose, but tool as shown at B to correctany run-out of the it may stick so hard you cannot easily center. The tool bit should be relieved remove it. under the If so, anneal the broken part of thedrill and drill cutting edge as shown at C toprevent the tool it out. from dragging or rubbing in the hole. The importance of having For proper center centerdrilling a workpiece,the holes in the work anda correct angle on the combined drill and countersinkis the most pointofthe practical lathecenterscannotbe tool.Thecombineddrillsand overemphasized. To do an accurate job between countersinks vary in size and thedrill points centers on the lathe, you must countersink holes also vary. Sometimes a drill point on one end of the proper size and depth, and besure the will be 1/8 inch in diameter and thedrill point points of the lathe centersare true and accurate. on the opposite end will be 3/16 inchin Figure 8-10 shows correct and diameter. The angle of the center drill incorrect is always countersinking for work to be machinedon 60° so that the countersunkhole will fit the angle of the lathe center point. If a center drill is not available,you may center the work with a small twist drill. Letthe drill enter the worka sufficient depth on each end; then follow witha countersink which has a 60° point. The drawing and tabulation infigure 8-9 shows the correct size of the countersunkcenter hole for the diameter of the work. In center drilling,use a drop or two of oil on the drill. Feed the drill slowly andcarefully so as not to break the tip. Use extremecare when the work is heavy, because it is thenmore difficult to "feel" the proper feed of the workon the center drill. If the center drill breaks in countersinking 28.114X and part of the broken drill remains inthe work, Figure 8.10. Examples of center holes.

8-7 2.12 MACHINERY REPAIRMAN 3 & 2

centers.InexampleA,thecorrectly In the incorrect example, the tail countersunk hole is deep enough of the dog so that the rests on the bottom of the sloton the faceplate point of the lathe centers doesnot come in at A, thereby pulling the work contact with the bottom of the hole. away from the center points, as shown at B and C, andcausing the work to revolve eccentrically. Inexample Boffigure8-10,the countersunk hole is too deep, causingonly the When you mount work betweencenters for outer edge of the work torest on the lathe machining, th"re should beno end play between center. Work cannot be machinedon centers the work and the dead center.However, if the countersunk in this manner. work is held too tightly by the tailcenter, when the work begins revolving it willheat the center Example C shows a piece of workthat has point and destroy both the centerand the work. been countersunk witha tool of an improper To prevent overheating, lubricatethe tail center angle. This work restson the point of the lathe with a heavy oil or a lubricant speciallymade for center only. It is evident that this workwill soon this purpose. destroy the end of the lathecenter, thus making it impossible to do an accurate job. HOLDING WORK ON A MANDREL

Mounting the Work Many parts, such, as bushings,gears, collars, and pulleys, require all thefinished external Figure 8-11shows correct and incorrect surfaces to run true with the holewhich extends methods of mounting work betweencenters. In through them. That is, theoutside diameter the correct example, the drivingdog is attached must be true with the inside diameteror bore. to the work and rigidly held by thesetscrew. General practice is to finish The tail of the dog rests in the hole to a the slot of the drive standard size, within the limit ofthe accuracy plate and extends beyond the baseof the slot so desired. Thus, a 3/4-inch standard that the work rests firmly hole will have on both the headstock a finished dimension of from 0.7505 center and tailstock center. to 0.7495 inch, or a tolerance of one-halfthousandth of an inch above or below the truestandard size of exactly 0.750 inch. First, drillor bore the hole to within a few thousandths ofan inch of the finished size; thenremove the remainder of the material with a machinereamer. Press the piece on a mandrel tightlyenough so the work will not slip while it ismachined and clamp a dogon the mandrel, which is mounted between centers. Sincethe mandrel surface runs true with respectto the lathe axis, the turned surfaces of the workon the mandrel will be true with respect to thehole In the piece. A mandrel is simplya round piece of steel of convenient length which has beencentered and turnedtruewiththecenters.Commercial mandrels are made of tool steel,hardened and ground with a slight taper (usually0.0005 inch per inch). On sizes up to 1 inch the smallend is usually one-half thousandth ofan inch under the 28.115X standard size of the mandrel, Figure 8.11.Examples of while on larger work mounted between sizes this dimension is usuallyone thousandth of centers. an inch under standard. This taper allowsthe

8-8 2 I 3 Chapter 8BASIC MACHINE LATHEOPERATIONS

standard hole in the work tovary according to SHELL the usual shop practice, and still providesthe necessaryfittodrivethe work when the mandrel is pressed into the hole. However,the taper is not great enough to distort the hole in thework. The countersunk centers ofthe mandrel are lapped for accuracy, while theends are turned smaller than the body of the mandrel and are provided with flats, which givea driving surface for the lathe dog. 28.118 The size of the mandrel is always markedon Figure 8.12. A split-shell expansion mandrel. the large end to avoid error and for convenience in placing work on it. The work isdriven or pressed on from the small end and removedthe the mandrel after the roughing cut and lightly same way. reloaded on the mandrel before the finishcut is When the hole in the work is not standard taken: size, or if no standard mandrel is available,make In addition to the standard lathemandrel a soft mandrel to fit the particular piece to be just described, thereare expansion mandrels, machined. gang mandrels, and eccentric mandrels. Use a few drops of oil to lubricatethe An EXPANSION mandrel is usedto hold surface of the mandrel before pressing it into the work that is reamed or bored tononstandard work, because clean, metallic surfaces gallor size. Figure 8-12 shows stick when pressed together. If an expansion mandrel you do not use composed of two parts: a tapered pin thathas a lubricant, the mandrel cannot be drivenout taper of approximately 1/16 inch for each without ruining the work. inch of length and an outer split shell that istapered Whenever you machine workon a mandrel, to fit the pin. The split shell is placed inthe be sure that the lathe centersare true and work and the tapered pin is forced intothe shell, accuratelyaligned;otherwise,thefinished causing it to expand until it properly holdsthe turned surface will not be true. Beforeturning work. accurate work, test the mandrel on centers A GANG mandrel (fig. 8-13) is usedfor before placing any work on it. The besttest for holding several duplicate pieces such run-out is made with a dial indicator. Mount as gear the blanks. The pieces are held tightlyagainst a indicator on the toolpost so that the 'pointof shoulder by a nut at the tailstock end. the indicator just touches the mandrel.As the mandrel is turned slowly betweencenters, any An ECCENTRIC mandrel hastwo sets of' run-out will be registered on the indicator dial. countersunkholes,onepairof whichis If run-outisindicated and you cannot correct it by adjusting the tailstock, the mandrel itself is at fault (assuming that the lathecenters are true) and cannot be used. The countersunk holes may have been damaged,or the mandrel may have been bent by careless handling. Be sure you always protect the ends of the mandrel when pressing or driving it into thework. A piece of work mounted ona mandrel must have a tighter press fit to the mandrel for roughing cuts than for finishing cuts. Thick-walled work can be left on the mandrel for the finishing cut 28.117 but thin-walled work should be removedfrom Figure 8-13.Gang mandrel.

8-9 21.E MACHINERY REPAIRMAN 3& 2

off-center an amount equal to theeccentricity of the workto be machined. Figure 8-14 illustrates its application: A isto be machined concentric with the hole in the work,while B is to be machined eccentric to it.

HOLDING WORK IN CHUCKS

The independent chuck anduniversal chuck are used more often than other, workholding devices in lathe operations. Auniversal chuck is used for holding relatively truecylindrical work when accurate concentricity ofthe machined surface and holdingpower of the chuck are COMPOUND REST secondary to the time requiredto do the job. An independent chuck is used whenthe work is irregular in shape, must be accuratelycentered, 28.119 or must be held securely for heavy feedsand Figure 8-15.Work mounted ina 4jrat independent depth of cut. chuck.

Four-Jaw Independent Chuck 2.Fasten the work in the chuck byturning Figure 8-15 shows a rough castingmounted the adjusting screw on jaw No. 1and jaw No. 3, in a four-jaw independent lathechuck on the a pair of jaws which are opposite eachother. spindle of the lathe. Beforetruing the work, Next tighten jaws No. 2 andNo. 4 (opposite determine which partyou wish to have turn each other). true. To mount a rough castingin the chuck, 3.At this stage the work shouldbe held in proceed as follows: the jaws just tightly enoughso it will not fall out of the chuck while being trued. 1. Adjust the .Chuck jaws toreceive the 4.Revolve the spindle slowly, andwith a casting. Each jaw should beconcentric with the piece of chalk mark the highspot (A in fig. ring marks indicatedon the face of the chuck. If 8-15) on the work while it there are no ring marks, is revolving. Steady set the jaws equally your hand on the toolpost while holdingthe distant from the circumferenceof the chuck chalk. body. 5.Stop the spindle. Locate thehigh spot on the work and adjust the jaws in theproper direction to true the work byreleasing the jaw opposite the chalk mark and tighteningthe one nearest the mark. 6.Sometimes the high spoton the work will be located between adjacentjaws. When it is, loosen the two opposite jawsandtighten the jaws adjacent to the highspot. 7. When the work isrunning true in the chuck, tighten the jaws gradually,working the jaws in pairs as describedpreviously, until all four jaws are clamping thework tightly. Be sure that the back of the workrests flat against the 28.118 inside face of the chuck,or against the faces of Figure 8-14. Work on an eccentricmandrel. the jaw stops (B in figure 8-15).

8-10 Chapter 8BASIC MACHINE LATHE OPERATIONS

Use thesameproceduretoclamp To mount rings or cylindrical disks on a semi-finished or ished pieces in the chuck, chuck, expand the chuck jaws against the inside except center theseeces more accurately in of the workpiece. (See fig. 8-17.) the chuck. If the run -oat tolerance is very small, use a dial indicator to determine the run-out. Regardlessofhowyoumountthe workpiece, NEVER leave the chuck wrench in Figure 8-16 illustrates the use of a dial test the chuck while the chuck is on the lathe indicator in centering work that hasa hole bored spindle. If the lathe should be started, the in its center. As the work is revolved, the high wrench could fly off the chuck and injure you spot is indicated on the dial of the instrument to or a bystander. a thousandth of an inch. The jaws of the chuck are adjusted on the work until the indicator Three-Jaw Universal Chuck hand registers no deviation as the work is revolved. A three-jaw universal, or scroll, chuck allows When the work consists of a number of all jaws to move together or apart in unison. A duplicate parts that are to be tightened in the universal chuck will center almost exactly at the chuck, release two adjacent jaws and remove the first clamping, but after a period of use it is not work. Place another piece in the chuck and uncommon to find inaccuracies of from .002 to retighten the two jaws just released. .01 0inchincenteringthework,and consequently the run-out of the work must be Each jaw of a lathe chuck, whether an corrected.Sometimes youcanmake the independent or a universal chuck, hasa number correction by inserting a piece of paper or thin stamped onitto correspond with a similar shim stock between the jaw and the work on the number on the chuck. When you remove a HIGH SIDE. chuck jaw for any reason,. you should always put it back into the proper slot. When chucking thin sections, be careful not toclamp the work tootightly,sincethe When the work to be chucked is frail or diameter of the piece will be machined while the light, tighten the jaw carefully so that the work will not bend, break, or spring.

ttr

28.121 28.120X Figure 8-17.Work held from inside by a 4 indepen- Figure 8.18. Centering work with a dial indicator. dent chuck. MACHINERY REPAIRMAN3 & 2 piecis distorted. When the presure of the jaws is r eased after the cut, the spindle shoulder and willprevent the chuck there be as many from running true. Screw hi spots as thereare jaws,nd the turned the chuck carefully surf ce will not betrue. onto the spindle and thethreads and make it difficulttoremovethechuck. Never use Dra -In Collet Chuck mechanical power to installa chuck, but rotate the spindle withyour left hand while you support the chuck in the hollowof your right A draw-in collet, ck is used for very fine arm. accurate Work of-sa eter. Long work can be passed, through the ow drawbar, and short To remove a small chuck, work can ,be placed directlyinto the collet from place a chuck the front. \ Tighten wrench in the square hole inone of the jaws and the collet on the workby strike a smart blow rotating the drawbarhandwheel to the right. on the wrench handle with This draws the collet your hand. To remove a heavychuck, rotate it into the tapered closing against a block of wood held sleeve; the oppositeoperation releases the collet. between a jaw and the lathe bed. Whenmounting or removinga heavy chuck, lay You will get themost accurate results when a board across the bedways to the diameter of the work protect them and to helpsupport the chuck as is the same as the you put it on or take it off. Most dimension stampedon the collet. The actual larger chucks diameter of the work are drilled and taped to accepta padeye for may vary from the collet lifting with a chainfall. dimension by ±0.001 inch.However, if the work diameter va ) 'esmore than this, the accuracy of the finished The procedures for mountingand removing ork will be affected.Most draw-in faceplates are the colletchucksetsare same as for mounting and sizedin1/64-inch removing chucks. increments fp allowyou to select a collet within the required tolerances. Figure 8-18 showsa simple device made of Rubber Rex Collet Chuck brass wire for cleaning thethreads of a chuckor faceplate. A rubber flex colletchuck is basically the same as the draw-in type collet,except that.the HOLDING WORK ON AFACEPLATE size (of the stock heldis not as critical.The rubl;ier colletsare graduated in 1/16-inch steps A faceplate is used formounting work that and will tighten down withaccuracy on any size cannot be chucked within the 1/16-inchrange. or turned between centers because of its peculiarshape. A faceplate is also CARE OF CHUCKS used when holesare to be accurately machined

To preserve a chuck'saccuracy, handle it carefully and keep it clean.Never force a chuck jaw by using a pipeas an extension on the chuck wrench.

Before mountinga chuck, remove the live center and fill the holewith a rag to prevent 'chips and dirt from gettinginto the taper hole of the spindle.

Clean and oil the threadsof the chuck and the spindle nose. Dirt 28.122X or chips on the threads Figure 8.18.Tool for cleaning will not allow the chuckto properly seat against thrssd of a chuckor faceplate.

8-12 217 Chapter 8BASIC MACHINE LATHEOPERATIONS

To mount work accuratelyon a faceplate, the surface of the work incontact with the faceplate must be accurate. Check theaccuracy with a dial indicator. Ifyou find run-out, reface the surface of the work that is incontact with the faceplate. It is good practice to placea piece of paper between the work and thefaceplate to keep the work from slipping. Before securely clamping the work,move it about on the surface of the faceplateuntil the point to be machined is centered accuratelyover the axis of the lathe. Supposeyou wish to bore a 28.123X hole, the center of which has been .laidout and Figure 8-19.Eccentiic machining of work mountedon marked with a prick punch. First,clamp the a faceplate. worktothe approximate positionon the faceplate. Then slide the tailstockup to where the dead center just touches the work.Note, the in flat work, as in figure 8-19,or when large and dead center should have ,irregularly shaped a sharp, true point. is to be faced on the Now revolve the work slowly and, if thework is lathe. off center, the point of the dead Work is secured ts :he faceplate by bolts, center will scribe a circle on the work. If the workis on clamps, or any suitable clampingmeans. The center, the point of the dead center will coincide ;It.) lel and slots in the faceplateare used to with the prick punch mark. anc).or the holding bolts. Angle platesmay be used to locate the work at the desiredangle, as HOLDING WORK ON THE CARRIAGE shown in figure 8-20. (Note thecounterweight added for balance.) If a piece of work is too largeor bulky to swing conveniently in a chuckor on a faceplate, you can bolt it to the carriage or the cross-slide ANGLE PLATE FACEPLATE and machine it with a cutter mountedon the spindle. Figure 8-21 showsa piece of work being machined by a fly cutter mounted ina boring bar which, is held between centers anddriven by a lathe dog.

4p LATHE SPINDLE

FLY CUTTER COUNTESWEIOHT001111. L.

to

......

28.124X 28.128X Figure 8.20. Work clamped toan angle plate. Figure 8-21.Work mountedon a carriage for boring. 8-1321 s MACHINERY REPAIRMAN 3& 2 USING THE CENTER REST AND FOLLOWER REST

Long slender work often requiressupport between its ends while it is turned;otherwise the work would springaway from the tool and chatter. The center rest is usedto support such work so it can be accurately turnedwith a faster feed and cutting speed thanwould be possible without the center rest. (See fig.8-22.) The center rest should be placedwhere it will give the greatest supportto the piece to be 28.126X turned. This is usually at about themiddle of its Figure 8-23.Work mounted ina chuck and center rest. length. Ensure that the center point between the center rest are used to machine theend of a jaws of the center rest coincides exactlywith the workpiece. axis of the lathe spindle. Todo this, place a short piece of stock in a chuck and machine it to The follower rest differs from thecenter rem the diameter of the workpieceto be supported. in that it moves with the carriage Without removing the stock and provider\ from the chuck, support against the forces of thecut. To use the clamp the center reston the ways of the lathe and adjust the jaws to the tool, turn a "spot" of the desiredfinish diameter machined surface. and about 5/8 to 3/4 inchwide on the Without changing the jawsettings, slide the center workpiece. Then, adjust the jaws ofthe follower restintopositiontosupportthe rest against the area you just machined. workpiece. Remove the stockused for setting The the center rest and set the follower rest will move with thecutting tool and workpiece in place. support the point of the work thatis being Use a dial Indicator to true theworkpiece at the machined. chuck. Figure 8-23 showshow a chuck and The follower rest (fig. 8-24) isindispensable for chasing threadson long screws, as it allows the cutting of ascrew with a uniform pitch

I O

28.125X Figure 8-22.Use of a centerrest to support work 28.127X Figure 8-24.Followerrest supporting screw while between centers. thread is being cut.

8-14 2 f) Chapter 8BASIC MACHINE LATHE OPERATIONS

diameter. Without the follower rest, thescrew CUTTING SPEEDS AND FEEDS would be inaccurate because it would spring away from the tool. Cutting speed is the rate at which the surface Use a sufficient amount of grease, oilor of the work passes the point of the cutting tool. other available lubricant on the jaws of the It is expressed in feet per minute (fpm). center rest and follower rest to prevent "seizing" To find the cutting speed, multiply the and scoring the workpiece. Check the jaws diameter of the work (DIA) in inches times frequently to see that they do not become hot. 3.1416 times the number of revolutions per The jaws may expand slightly if they get hot minute (rpm) and divide by 12. thug pushing the work out of alignment (when the follower rest is used) or binding (when the CS DIA X 3.1416 X rpm center rest is used). 12

The result is the peripheral or cutting speed MACHINING OPERATIONS infeet per minute. For example, a 2-inch diameter part turning at 100 rpm will producea Up tothis point, you have studied the cutting speed of preliminary steps leading up to the performance of machine work in the lathe. You have learned 2 X 3.1416 X 100 how to mount the work and the tool, and which 12 52.36 fpm tools are used for various purposes. The next step is to learn how to use the lathe to turn, If you have selected a recommended cutting bore, and face the work to the desired formor speed from a chart for a specific type of metal, shape. you will need to figure what rpm is required to TURNING is the machining of the outside obtain the recommended cutting speed, or feet surface of a cylinder. per minute. This may be done by the following BORING is the machining of the inside formula: surface of a cylinder. FACING is the machining of flat surfaces. CS X 12 Remember thataccuracyistheprime rpmDIA X 3.1416 requisite of a good machine job; so beforeyou start, be sure that the centers are true and Table 8-1givestheapproximate properly aligned,that the work is mounted recommended cutting speeds for various metals, properly, and that the cutting tools are correctly using a high-speed steel tool bit. To obtainan ground and sharpened. approximate cutting speed for the other types of cuttingtoolmaterials multiplythecutting PLANNING THE JOB speeds recommended in table 8-1 and other charts,which youwillfindindifferent It is important that you study the blueprint handbooks, by the following factors: of the part to be manufactured beforeyou begin machining. Check over the dimensions and note Carbon steel tools 50% of HSS, multiply the points or surfaces from which they are laid by 0.5 out. Plan the steps of your work in advance to determine the best way to proceed. Check the Cast alloy tools 160% of HSS, multiply by overall dimensions and be sure that the stock 1.6 you intend to use is large enough for the job. For example, small design features, suchas Carbide tools 200% to 400% of HSS, collars on pump shafts or valve stems, will multiply by 2.0 to 4.0 require that you use stock of much larger diameterthanthatrequiredforthemain Ceramic tools 400% to 1600% of HSS, features of the workpiece. multiply by 4.0 to 16.0

8-15 24) MACHINERY REPAIRMAN 3 8E'2

Table 8-1.Cutting Speeds UsingHigh-speed Steel Tool obtaining the feed desired. The Bits amount of feed to use is best determined fromexperience. Cutting speeds and tool feedsare cetermined by various considerations:the hardness and TYPE OF MATERIAL Cutting toughness of the metal beingcut; the quality, Speed (fpm) shape, and sharpness of the cuttingtool; the depth of the cut; the tendencyof the work to spring away from the tool; and therigidity and Low carbon steel 40.140 power of the lathe. Since conditionsvary, it is good practice to find out whatthe tool and Medium carbon steel 70-120 workwill stand, and then select themost practicableandefficientspeedandfeed High carbon steel 65-100 consistent with the finish desired. If the cutting speed is too slow, Stainless steel, Cl 302, 304 the job takes 60 longer than necessary and thework produced is often unsatisfactory because of Stainless steel, C 1 310, 316 a poor finish. On 70 the other hand, if the speed istoo great the tool edge will dull quickly and willrequire frequent Stainless steel, CI 410 100 regrinding. The cutting speedspossibleare greatly affected by the Stainless steel, Cl 416 use of a suitable cutting 140 lubricant. For example, steelthat can be rough turned dry at 60 rpmcan be turned at about 80 Stainless steel, CI 17-4, pH 50 rpm when flooded with a good cutting lubricant. Alloy steel, SAE 4130, 4140 70 When ROUGHING parts downto size, use the greatest depth of cut and*feed Alloy steel, SAE 4030 per revolution 90 that the work, the machine,and the tool will stand at the highest practicable Gray cast iron speed. On many 20-90 pieces, wheh tool failure is thelimiting factor in the size of roughing cut, it is Aluminum alloys usually possible to 600-750 reduce the speed slightly andincrease the feed Brass to a point that the metalremoved is much 200-350 greater. This will prolong toil life.Consider an example when the depth of Bronze cut is 1/4 inch, the 100-110 feed 20 thousandths ofan inch per revolution, and the speed 80 fpm. If the Nickel alloy, Monel 400 tool will not permit 40-60 additional feed at this speed,you can usually drop the speed to 60 fpmand increase the feed Nickel alloy, Monel K500 30-60 to about 40° thousandthsof an inch per revolution without having tool Nickel alloy, Inconel trouble. The 5-10 speed is therefore reduced 25%but the feed is increased 100%. The actual Titanium alloy time required to 20-60 complete the work is less withthe second setup.

FEED is the amount the tool On the FINISH TURNINGOPERATION, a advances in very light cut is taken since most of thestock each revolution of the work.Itis usually has been removed expressedin on the roughing cut. A fine thousandths of an inchper feed can usually be used, revolution of the spindle._ Theindex plate on the making it possible to quick-change gear box indicates run a high surface speed. A 50%increase in the setup for speed over the roughing speedis commonly

8-16 Chapter 8BASIC MACHINE LATHE OPERATIONS used. In particular cases, the finishing speedmay While the use of a lubricant for straight be twice the roughing speed. In any ev'nt, the turning isdesirable, itis very impertant for work should be run as fast as the tool will threading. The various operations used and withstand to obtain the maximum speed in this materials machined onalathe may cause operation. A sharp tool should be used to finish problemsintheselectionof theproper "turning. lubricant. A possible solution is to selecta lubricant that is suitable for the majority of the materials you plan to work with. Coolants Chatter

Acuttinglubricantservestwomain A symptom of improper lathe operation is purposes: (1) It cools the tool by absorbing a known as"chatter." Chatter is vibration in portion of the heat and reduces the friction either the tool or the work. The finished work between the tool and the metal being cut. (2) It surface will appear to have a groovedor lined keeps the cutting edge of the tool flushed clean. finish instead of the smooth surface that is A cutting lubricant generally allowsyou to use a expected. The vibration is set up bya weakness higher cutting speed, heavier feeds, and depths in the work, work support, cool, Or tool support of cut than if you performed the machinery and is perhaps the most elusive thingyou will operation dry. The life of the cutting tool is also find in the entire field of machine work. Asa prolongedbylubricants.Some common general rule, strengthening the various parts of materials and their cutting lubricantsare as the tool support trainwill help.Itis also follows: advisable to support the work by a center restor follower rest. Cast ironusually worked dryor with a soluble oil mixture of 1part of oil to 30 Begin your search for the cause of the parts of water or mineral lard oil. chatter by making sure that the surface speed is not excessive. Since excessive speed is probably Alloy steelsoluble oil mixture of 1 part of the most frequent cause of chatter, reduce the oil to 10 parts of water or mineral lard oil. speed and see if the chatter stops. Youmay also increase the feed, particularly if youare taking a Lo w/mediumcarbonsteelsolubleoil rough cut and the finishisnot important. mixture of 1 part of oil to 20 parts of water Another adjustment you can try is to reduce the or mineral lard oil. lead angle of the tool (the angle formed between the surface of the work and the side cutting edge Brasses and bronzessoluble oil mixture of 1 of the tool). You may do this by positioning the part of oil to. 20 parts of water or mineral tool closer to a perpendicular to the work. lard oil. If none of the above actions work, examine Stainless steelsoluble oil mixture of 1 part the lathe and its adjustments. Gibsmay be too of oil to 5 parts of water or mineral lard oil. loose or bearings may be worn aftera long period of heavy service. If the machine is in Aluminumsoluble oil mixture of 1 part of perfect condition, the fault may be in the tool oil to 25 parts of water or dry. or the tool setup. Check to be sure the tool has been properly sharpened to a point or as near to Nickel alloys/Monelsoluble oil mixture of 1 a point as the specifiedfinish will permit. part of oilto 20 parts of water or a Reduce the overhang of the toolas much as sulfur-based oil. possibleand recheckthegib and bearing adjustments. Finally, be sure that the work is Babbittdry or with a mixture of mineral properly supported and that the cutting speed is lard oil and kerosene. not too high.

8-17 2.) MACHINERY REPAIRMAN 3& 2 Direction of Feed

Regardless of how the work isheld in the lathe,thetoolshouldfeedtowardthe headstock. This causes most ofthe pressure of the cut to be exertedon the workholding device and the spindle thrust bearings.When you must feed the cutting tool toward thetailstock, take lighter cuts at reduced feeds. Infacing, the general practice is to feed thetool from the centeroftheworkpiece out towardthe periphery.

FACING 28.130X Figure 8-28.Facing a shoulder. Facing is the machining ofthe end surfaces and shoulders ofa workpiece. In addition to the outside of the smallerdiameter section. squaring the ends of the work,facing will let you Next, machine the fillet witha light cut by accuratelycuttheworktolength. manipulating the apron handwheel Generally, in facing the workpiece and the you will need crossfeed handle in unisonto produce a smooth to take only light cuts sincethe work has rounded surface. Finally, already been cut to approximate use the tool to face length or rough from the fillet to the outsidediameter of the machined to the shoulder. work. Figure 8-25 shows howto face a cylindrical piece. Place the'Workon centers and install a cIn facing large surfaces, backthe carriage in dog. Using.a" right-hand sidetool, take one or position since onlycross feed is required to two light cuts from the centeroutward to true traverse the tool across the work.With the the 'rk. compound rest set at 90° (parallelto the axis of ". If both ends of the workmust be faced, the lathe), use the micrometercollar to feed the reverse the piece so that the dog drivesthe end tool to the proper depth ofcut in the face. For just faced. Usea steel ruler to layout the greater accuracy in gettinga given size when required length, measuring fromthe faced end finishing a face, set the compoundrest at 30°. In to the end to be faced. Afteryou ensure that thisposition,.001-inch movement of the there is no burr on the. finishedend to cause an compound restwill move the tool exactly inaccurate measurement, markoff the desired .0005-inch in a direction parallelto the axis of dimension with a scribe andface the second end. the lathe. (In a 30°- 60° right triangle, the length of the side opposite the 30°angle is equal Figure 8-26 shows the facingof a shoulder to one-half of the length of the having a fillet corner. First, takea finish cut on hypotenuse.) TURNING

Turning is the machining ofexcess stock sePOINT from the periphery of theworkpiece to reduce TOP VIEW the diameter. Bear in mindthat the diameter of ?Pr", the work being turned isreduced by the amount !of equal to twice the depthof the cut; thus, to SIDE VIEW END VIEW reduce the diameter ofa piece by 1/4 inch, you must remove 1/8 inch of metal fromthe surface. 28.129X To remove large amount ofstock in most Figure 8-25.Right-hand sidetool. lathe machining,youwill take a series of

8-18 223 Chapter 8BASIC MACHINE LATHE OPERATIONS roughing cuts to remove most of the excess. becomingworn. Always checkthecenter stock and then take a finishing cut to accurately carefully and adjust as needed during rough "size" the workpiece. turning operations. Rough Turning Figure 8-28 shows the position of the tool for taking a heavy chip on large work. Set the Figure 8-27 illustrates a lathe taking a heavy tool so that if anything causes it to change cut. This is called rough turning. When a great position during the machining operation, the deal of stock is to be removed, you should take toolwill move away from the work, thus heavy cuts in order to complete the job in the preventing damage to the work. Also, setting the least possible time. tool in this position may prevent chatter. Be sure to select the proper tool for taking a heavy chip. The speed of the work and the Finish Turning amount of feed of the tool should be as great as the tool will stand. When the work has been rough turned to When taking a roughing cut on steel, cast within about 1/32 inch of the finished size, take iron, or any other metal that has a scale on its a finishing cut. A fine feed, the proper lubricant, surface, be sure to set the tool deep enough to and above all a keen-edged tool are necessary to get under the scale in the first cut. Unless you produce a smooth finish. Measure carefully to be do, the scale on the metal will dull the point of sure that you are machining the work to the the tool. proper dimension. Stop the lathe whenever you Rough machine the work to almost the take any measurements. finished size; then be very careful in measuring. If you must finish the work to extremely Oftentheheat produced during rough close tolerances, wait until the piece is cool turning will expand the workpiece, and the before taking the finish cut. If you take the lubricant will flow out of the live center hole. finish cut while the piece is hot and slightly This will result in both center and center hole expanded, the piece will be undersize after it has cooled and contracted. If you plantofinishthe work on a cylindricalgrinder,leavethe stockslightly oversize to allow for the metal the grinder will remove. Perhaps the most difficult operation for a beginner in machine work is to make accurate measurements.So muchdependsonthe accuracy of the work that you should make everyeffortto become proficient in using

28.131X 28.132X Figure 8-27.Rough turning. Figure 8-28.Position of tool for heavy cut.

8-19 224 MACHINERY REPAIRMAN 3 &2 measuring instruments. You will developa in the lathe or to cut tubingand bar stock to certain "feel" through experience.Do not be required lengths. discouraged if your first efforts donot produce perfect results. Practice taking measurements on Parting tools can be the insertedblade type pieces of know dimensions. You willacquire the skill if you are persistent. or can be ground from a standard toolblank. Figure 8-30 shows the twotypes of parting tools. For the tool to have Turning to a Shoulder maximum strength, the length of the cutting portionof the blade that extends from the holder shouldbe only A time saving procedure formachining a slightly greater than half the diameter shoulder is illustrated in figure of the 8-29. First, locate work to parted. Place the endcutting edge of and scribe the exact locationof the shoulder on the parting tool exactly the work. Next, use on the centerline of the a parting tool to machine a lathe. To do this, placea center in the tailstock groove 1/32 inch from the scribe line towardthe and align the parting tool withthe tip of the smaller finish diameter end and 1/32larger than the smaller finish diameter. Thentake heavy cuts up to the shoulder made bythe parting tool. Finally, take a finishcut from the small STRAIGHT HOLDER end to the shoulder scribe line.This procedure eliminates detailed measuring andspeeds up production.

LEFT HAND OFFSET PARTING AND GROOVING

One of the methods of cutting offa piece of stock while it is held in INSERTED a lathe is a process called BLADE parting. This processuses a specially shaped tool with a cutting edge similarto that of a square nose tool. The parting tool is fedinto the rotating work, perpendicularto its axis, cutting a progressivelydeeper grooveasthe work rotates. When the cutting edge ofthe tool gets to the center of the work beingparted, the work A. HOLDERS drops off as if it were sawed off.Parting is used to cut off parts that have alreadybeen machined

B. TOOL OFFSET 28.133X Figure 8-29.Mechining to a shoulder. Figure 8.30. Parting tools.

8-20 Chapter 8BASIC MACHINE LATHE OPERATIONS center. The chuck should hold the work to be start the drilling operation by drilling a center parted with the point at which the parting is to hole in the work, using a combination center occur as close as possible to the chuck jaws. drillandcountersink.Thecombination Always make the, parting cut at a right angle to countersink-centerdrill is held in a drill chuck the centerline of the work. Feed the tool into which is mounted in the tailstock spindle. After the revolving work with the cross-slide until the you have center drilled the work, replace the tool completely severs the work. drill chuck with a taper shank drill. (Note: BEFORE you insert any tool into the tailstock Cutting speeds for parting are usually slower spindle, inspect the shank of the tool for burrs. than turning speeds. You should use a feed that If the shan't 's burred, remove the burrs with a will keep a thin chip coming from the work. If handstone.) Feed the drill into the work by chatter occurs, decrease the speed and increase usingthetailstockhandwheel.Usea the feed slightly. If the tool tends to gougeor coolant /lubricantwheneverpossibleand dig in, decrease the feed. maintainsufficient pressure on thedrillto prevent chatter, but not enough to overheat the Grooves are machined in shafts to provide drill. for tool runout in threading to a shoulder, to allow clearance for assembly of parts, to provide If the hole is quite long, back the drill out lubricating channels, or to provide a seating occasionally to clear the flutes of metal chips. surface for seals and 0-rings. Square, round, and Large diameter holes ma require you to drill a "V" grooves and the tools which are used to pilot hole first. This isne with a drill that is produce them are shown in figure 8-31. smaller than the fini diameter of the hole. After you have ed the pilot hole to the The grooving tool is a type of forming tool. proper depth,nlarge the hole with the finish It is ground without side rake or back rake and drill. If you p an to drill the hole completely isset tothe work at center height with a through the w rk; slow down the feed as the minimum of overhang. The side and end relief drill nears the hole exit. This will produce a angles are generally somewhat less than for smoother exit hole by causing the drill to take a turning tools. When you machine a groove, finer cut as it exits the hole. reduce the spindle speed to prevent chatter which often develops at high speeds because of If the twist drill is not ground correctly, the the greater amount of tool contact with the drilled hole will be either excessively oversized work. or out of round. Check the drill for the correct angle,clearance,cutting edgelengths and DRILLING AND REAMING straightness before setting it up for drilling. It is almost impossible to drill a hole exactly the same size as the drill regardless of the care taken Drilling operations performed ina lathe in ensuring an accurately ground drill and the differverylittlefromdrillingoperations proper selection of speeds and feeds. For this performed in a drilling machine. For best results, reason, any job which requires close tolerances or a good finish on the hole should be reamed or bored to the correct size.

If the job requires that the hole be reamed, allY1.1111..17 L it is good practice to first take a cleanup cut SOUARI ROUND through the hole with a boring tool. This will OROOve OROOve true up the hole for the reaming operation. Be sure to leave about 1/64 inch for reaming. The machine reamer has a taper shank and is held in and fed by the tailstock. To avoid overheating Figure 8-31.Three common types of grooves. the reamer, the work speed should be about half

8-21 22G MACHINERY REPAIRMAN3 & 2

that used for the drillingoperation. During the reamingoperation,keepthereamerwell lubricated. This will keep thereamer cool and also flush the chips from theflutes. Do not feed the reamer too fast; itmay tear the surface of the hole and ruin the work.

BORING

Boring is the machiningof holes or any interior cylindrical surface.The piece to be bored must havea drilled or core hole, and the hole must be large enoughto insert the tool. The boring process merely enlargesthe hole to the desired size or shape. Theadvantage of boring is that you get a perfectlytrue round hole. Also, you can bore two or more holes ofthe same or different diameters atone setting, thus ensuring absolute alignment of theaxis of the holes.

It is usual practiceto bore a hole to withina few thousandths ofan inch of the desired size 28.134 Figure 8-32.Various boringbars. and then finishitto the exact size witha reamer. setscrew. The other setscrew, Work to be boredmay be held in a chuck, bearing on the end of the cutter, is for adjustingthe cutter to the bolted to the faceplate,or bolted to the carriage. work. Long pieces must be supportedat the free end of a center rest. Part B of figure 8-32shows a boring bar When the boring tool is fedinto the hole in fitted with a two-edgecutter held by a taper work being rotatedon a chuck or faceplate, the key. This ismore of a finishing or sizing cutter, process is cged single point boring.It is the asitcuts on bothsides and is used for same as turning except that the cuttingchip is production work. taken from the inside. Thecutting edge of the boring tool resembles thatof a turning tool. The boring bar shown inpart C of figure Boring tools may be thesolid forged type or the 8-32 is fitted witha cast iron head to adapt it inserted cutter bit type. for boring work of largediameter. The head is fitted with a fly cuttersimilar to theone shown When the work to be boredis clamped o in part A. The setscrewwith. the tapered point the top of the carriage,a boring bar is h d adjusts the cutter to the work. between centers and drivenby a dog. The rk is fed to the tool by theautomatic longitudinal feed of the carriage. Three Figure 8-33 showsa common type of boring types of boring bars bar holder and applications are shown in figure 8-32. Note the of the boring bar for countersunk boring and internal threading. center holes at the ends to fitthe lathe centers. When threading is to be done in a blind hole, itsometimes becomes Part A of figure 8-32 necessary to undercut or relieve thebottom of shows a boring bar the hole. This will enable fitted with a flycutter held by a headless mating parts to be screwed all the way to theshoulder and make 8-22 2'7 Chapter 8BASIC MACHINE LATHE OPERATIONS

half the roughing speed for the type of metal being machined. The feed should be between 0.015 inch and 0.025 inch per revolution. The work should be rigidly mounted in the tailstock to help offset the pressure exerted by the knurling operation.

The actual knurling operation is simple if you follow a few basic rules. The first step is to make sure that the rolls in the knurling tool turn freely and are free of chips and imbedded metal between the cutting edges. During the knurling process, apply an ample supply of oil at the point of contact to flush away chips and provide lubrication. Position the carriage so that 1/3 to 1/2 of the face of the rolls extends beyond the end of the work. This eliminates part of the pressure required to start the knurl impression. Force the knurling rolls into contact with the work. Engage the spindle clutch. Check the knurl to see if the rolls have tracked properly,as shown in figure 8-34, by disengaging the clutch after the work has revolyed 3 or 4 times and by backing the knurling tool away from the work.

If the knurls have double tracked,as shown 28.135 in figure 8-34, move the knurling tool coa new Figure 8-33.Application of boring bar holder. location and repeat the operation. If the knurl is correctly formed, engage the spindle clutch and the carriage feed. Move the knurling rolls into thethreadingoperationmucheasierto contact with thecorrectlyformed knurled accomplish. impressions. The rolls will align themselves with the impressions. Allow the knurling tool to feed to within about 1 /32 inch of the end of the KNURLING surface to be knurled. Disengage the carriage Knurlingistheprocessofrollingor squeezingimpressionsintothe work with hardened steel rollers that have teeth milled in DOUBLE their faces. Examples of the various knurling IM PR ESSI 01N -INCORRECT patterns are shown in chapter 7, figure 7 -22. Knurling provides a gripping surfaceon the work; it is used also for decoration. Knurling increases the diameter of the workpiece slightly when the metal is raised by the forming action of the knurl rolls. The knurimg tool (fig. 7-23) is set up so that CORRECT,/' the faces of the rolls are parallel to the surface IMPRESSION of the work and with the upper and lower rolls equally spaced above and below the work axisor centerline. The spindle speed should be about Figure 8-34.Knurled impressions.

8-23 MACHINERY REPAIRMAN3 & 2 feed and with the workrevolving, feed the ,qarriage by hand to extend theknurl to the end of the surface. Force the knurlingtool slightly deeper into the work,reverse the direction of feed and engage the carriage feed.Allow the knurling tool to feed until theopposite end of the knurled surface is reached.Never allow the knurls to feed off the surface.

Repeat the knurling operationuntil the diamond impressionsconverge to a point. Passes made after the correct shapeis obtained will result in stripping WHEEL away the points of the knurl. GUARD Clean the knurl witha brush and remove any burrs or sharp edges with a file. When knurling, GRINDING do not let the work rotatewhile the tool is in contact with it if the feed isdisengaged. This will cause rings to be formedon the surface, as shown in figure 8-35. Figure 8-36.Toolpost grinder.

SETTING UP THE TOOLPOST GRINDER asa cutting tool. Cylindrical, tapered, and internalsurfacescan be ground withthe toolpost grinder. Very small grinding The toolpost grinder isa portable grinding wheels are mounted on tapered shafts, knownas quills, to machine that can be mountedon the compound grind internal surfaces. rest of a lathe in place of the toolpost.It can be used to machine work that istoo hard to cut by ordinary means or The grinding wheel speedis changed by to machine work that using various sizes of pulleyson the motor and requires a very fine finish. Figure8-36 shows a spindle typical toolpost grinder. shafts. An instruction plateon the grinder gives both the diameterof the pulleys requiredtoobtain a given The grinder must be seton center, as shown speed and the in figure 8-37. The centering maximum safe speed for grindingwheels of holes located on various diameters. Grindingwheels are safe for the spindle shaft are used forthis purpose. The operationat a speed just below the grinding wheel takes the placeof a lathe cutting highest tool; it can perform most ofthe same operations

TOOL POST GRINDER SPINDLE HEADSTOCK SPINDLE

RINGS ON WORK CAUSED BY STOPPING TOOL TRAVEL WITH WORK REVOLVING

Figure 8-35.Ringsona knurled surface. Figure 8-37.Mounting the grinderat center height.

8-24 Chapter8JBASICMACHINE LATHE OPERATIONS,

reco mendedspeed. higherthan face of the wheel is parallel to the reco mended speed m ways of the cause the wheel to lathe. Move the compound rest if the face ofthe disint grate. For thisason, wheel guards are wheel is at at angle. Make the final depth of furni cut ed with thoolpost grinder to protect of 0.0001 inch witha slow, even feed to obtainN ag injury. a good wheelfinish. Remove the diamond Always check the pulley combinations given dresser holder as soon as you finish dressing the on the instructi plate of the grinder when you wheel andadjust the grinder to begin the grinding operation. mount a whe .Be sure that the combination is of rev , because this may cause the wheel torunata speedfarinexcess of that Rotate the work at a fairly low speed during recommended. During all grinding operations, thegrindingoperation The recommended wear goggles to protect your eyes from flying surface foot speed is 60 to 100 feetper minute abrasive material. (fpm). The depth of cut dependsupon the hardness of the work, the type of grinding The grinding wheel must be dressedand wheel, and the desiredfinish. Avoid taking trued. Use a diamond wheel dresser to dressand grinding cuts deeper than 0.002 inch untilyou true the wheel. The dresser is held ina holder gain experience. Use a fairly lowrate of feed. that is clamped to the chuckor faceplate of the You will soon be able to judge whetherthe feed lathe. Set the point of the diamondat center should be Increased or decreased. Never stopthe height and at a 10° to 15° angle in the direction work or the grinding wheel while theyare in of the grinding wheel rotation,as shown in contact with each other. figure 8-38. The 10° to 15° angle prevents the diamond from gouging the wheel. Lock the lathe To refinish a damaged lathe center,you spindle by placing the spindle speedcontrol shouldfirstinstallheadstock and tailstock lever in the low rpm position. (Note: Thelathe centers after ensuring that the spindle holes, drill spindle does not revolve whenyou are dressing sleeves, and centers are clean and free of burrs. the grinding wheel.) Next, position the compound rest parallelto the ways; then, mount the toolpost grinder on the Bring the grinding wheel in contact withthe compound rest. Make sure that the grinding diamond by carefully feeding the cross-slide in wheel spindle is at center height andaligned by hand. Move the wheel clear of thediamond with the lathe centers. Move the compound and make a cut by means of the rest cross-slide. The 30° to the right of the lathespindle axis, as maximum depth of cut is 0.002 inch. Move the shown in figure 8-5. Mount the wheel dresser, wheel slowly by hand back and forthover the covering the ways and carriage withrAp. to point of the diamond. Move the carriage if the protect them from abrasiveparticlesVWear goggles to protect your eyes. Start,the grinding motor, by alternately turning it on and off (let itrun a bit longer each time) until the abrasive wheel in broughtup to top speed. Dress the wheel, feeding thegrinder with the compound rest. Thenmove the grinder clear of the headstock center andremove the wheel dresser. Set the lathe forthe desired spindle speed and engage the spindle.Pick up the surface of the center. Takea light depth of cut and feed the grinder back and forth withthe compound rest. Do not allow the abrasive wheel to feed entirely off the center. Continue taking additional cuts until the center cleansup. To Figure 8-3B\Position of the diamond dresser. produce a good finish, reduce the feedrate and

8-25 23 MACHINERY REPAIRMAN 3& 2

the depth of cut to .0005. Grindoff the center's sharp point, leaving a flat witha diameter about 1/32inch. Move the grinderclear of the headstock and turn it off.

Figure 8-39 illustrates refacingthe seat of a high-pressure steam valve whichhas a hard, Stellite-faced 'surface. The refacingmust be done with a toolpost grinder. Besure that all inside diameters run true before startingthe machine work. Spindle speed of thelathe should be about 40 rpm or 1es.i. Too higha speed will cause the grinding wheel to vibrate. Setthe compound rest to correspond withthe valve seat angle. Use the cross-slide .handfeed or the micrometer stop on the carriagefor controlling depth of cut;use the compound rest for traversing the grinding wheelacross the work surface. When grindingon a lathe, always place a cloth across the ways of the bedand over any other machined surfaces thatcould become contaminated from grinding dust. 28.136 Figure 8-39.Refacing seat ofhigh-pressure steam valve.

8-26 CHAPTER 9

ADVANCEDENGINELATHE OPERATIONS

In chapter 8 you studied a number of lathe operations, the various methods of holdingand centering work on the engine lathe, and howto set lathe tools. This chapter is a continuation of engine lathe operations and deals primarilywith cutting tapers, boring, and cuttingscrew threads.

TAPERS

Taper is the gradual decreas4 the diameter of thickness of a piece of work towardone end. 12' To find the amount of taper inany g. ; ten length TAMER 2' Pt! ...... of work, subtract thksize of the small endfrom the size of thelae end. Taper is usually IL NO. expressed as the amount of taperper foot of length, or as an angle. The following examples ...... explain how to determine taperper foot of length. EXAMPLE 1: Find the taperper foot of a 28.137 piece of work 2 inches long: Diameter ofthe Figure 9-1.Tapers. small end is 1 inch; diameter of the large endis 2 inches.

The amount of the taper is 2 inches minus1 computing the taper. If you bear this in mind inch, which equals 1inch. The length of the when machining tapers, you will notgo wrong.. taper is given as 2 inches. Therefore, the taper is Use the formula: ./ 1 inch in 2 inches of length. In 12 inches of length it would be 6 inches. (See fig. 9-1.) TPF =FPI X 12 EXAMPLE 2: Find the taperper foot of a piece 6 inches long...Dia:peter of the smallend is where: TPF = TAPER PER FOOT 1 inch; diameter of the..:e end is. 2 inches. The amount of r is the same as in example1;thatis, 1 inch. (Seefig.9-1.) T = TAPER (Difference between However, the length of this taper is 6 inches; largeand small diameters), hencethetaperperfootislinch X expressed in inches 12/6 = 2 inches per foot. From the foregoing, youcan see that the L = LENGTH of taper, expressed length of a tapered piece isvery important in in inches

9-1 MACHINERY REPAIRMAN 3 &2

Other formulas used in figuringtapers are as with a taper: the included angle follows: and the angle with the centerline. The includedangle is the TPI = angle between the two angled sidesof the taper. L The angle with the centerlineisthe angle between the centerline and either of where:TPI = TAPER PER INCH the angled sides.Since thetaperisturned about a centerline, the angle between T = TAPER (Difference between one side and the centerline is always equal to the anglebetween largeand small diameters), the other side and the centerline. expressed in inches Therefore, the included angle is always twice the anglewith the centerline. The importance of thisrelationship L = LENGTH of taper, expressed will be shown later in this chapter. in inches Table 9-1 is a machinist'schartshowingtherelationship between taper per foot, includedangle, and L X TPF angle with the centerline. 12 andT=TPIXL There are 'several well-knowntapers that are used as standards for machines TPI =TPF on which they are used. These standards make it possibleto make or get parts to fit the machine inquestion without detailed measuring andfitting. By Tapers are frequently cut bysetting the designatingthe name and number of the angle of the taperon the appropriate lathe standard taper being used,you can immediately attachment. There are two anglesassociated find the length, the diameterof the small and

Table 9.1. Tapers Per Foot/Angles

Taper per foot Angle included Angle with centerline Taper per inch from centerline

Degrees Minutes 1/8 Degrees Minutes Inches 0 36 0 3/16 0 18 0.01042 54 0 27 1/4 1 12 .01563 0 36 .02083 5/16 1 30 3/8 0 45 .02604 1 47 0 54 7/18 2 .03125 5 1 3 1/2 2 .03646 23 1 12 9/16 2 .04187 41 1 21 5/8 3 .04888 0 1 30 11/16.... 3 .05208 17 1 38 3/4 3 .05729 35 1 47 ', . . . .08250 13/16 . 3 53 1 f 58 7/8 4 .08771 11 2 5 15/16.. . . 4 .07292 28 2 14 1 4 .07813 46 2 23 2 9 32 .08333 4 48 .16667

28.183.0 9-2 2;23 Chapter 9ADVANCED ENGINE LATHEOPERATIONS

large ends, the taper per foot, and all other cutting tool to move at an angle to the axis of pertinent measurements in appropriate tables the lathe. found in most machinist's handbooks. There are three methods in commonuse for There are three standard tapers with which turning tapers: you should be familiar: (1) the MORSE TAPER (approximately 5/8 inch per foot) used for the 1.SET OVER THE TAILSTOCK, which taper holes in lathe and drillpress spindles and the attachments that fit them, suchas lathe moves the dead center away from the axis of the centers, drill shanks, etc; (2) the BROWN & latheandcauses work supported between centers to be at an angle with the axis of the SHARPE TAPER (1/2 inch per foot exceptNo. lathe. 10 which is 0.5161 inchper foot) used for milling machine spindle shanks; and (3)the 2. USE THE COMPOUND REST MILLING of 3.5 inchesper set at an foot used by some manufacturers because of angle, which causes the cutting tool to be fedat the the desired angle to the axis of the lathe. easewithwhichitsdimensionscanbe determined: 3. USE THE TAPER ATTACHMENT, which also causes the cutting tool tomove at an Diameter of large end taper number angle to the axis of the lathe. 8 In the first method, the cutting tool is fed Diameter of small end taper number 10 by the longitudinal feed parallel to thelathe axis, but- a-taper is produced because the work axis is at an angle. In the second andthird Length of taper =taper number methods, the work axis coincides with thelathe 2 axis, but a taper is produced because the cutting tool moves at an angle. Two additional tapers whichare considered sta,dard are the tapered pin and pipethread tapers. Tapered pins have a taper of 1/4 inchper Setting Over the Tailstock foot while tapered pipe threads havea taper of 3/4 inch per foot.

A copy of a Morse taper table is shown in As stated in chapter 7, youcan move the tailstock top sideways on its base by using figure 9-2. You will no doubt havemore use for the this taper than any other standard taper. adjusting screws. In straight turning,you will recall that you used these adjustingscrews to align the dead center with the tail centerby METHODS OF TURNING TAPERS moving the tailstock to bring iton the centerline of the spindleaxis. For taper turning,you deliberately move the tailstock off center,and the amount you move it determines the In ordinary straight turning, the cuttingtool taper moves along a line parallel to the axis of the produced. You can approximate the amount of work, causing the finished job to be setover by the zero lines inscribedon the base the same and top of the tailstock as shown in figure 9-3. diameter throughout. If, however, incutting, the Then for final adjustment, tool moves at an angle to the axis ofthe work, a measure the setover taper will be produced. Therefore, with a scale between center pointsas illustrated to turn a in figure 9-4. taper, you must either mount the workin the lathe so the axis upon which it turns isat an In turning a taper by angle to the axis of the lathe, this method, the or cause the distancebetweencentersisofutmost MACHINERY REPAIRMAN 3 & 2

DETAIL DIMENSIONS

Number of Taper 0 1 2 3 4 5 6 7

Diameter of plug at small end.. D0.2520.369 0.572 0.7781.020 1.4752.1162.750 Diameter at end of socket.... A .3561 .475 .700 .9381.231.1.7482.4943.270 Shank: Whole length of shank B2-11/322-9/16 3-1/8 3-7/84-7/86-1/88- 9/1611-5/8 Shank depth S2-7/322-7/162-15/163-11/164-5/8 5-7/88- 1/411-1/4 Depth of hole H2-1/322-3/16 2-5/8 3-1/44-1/8 :-.-1/4 7- 3/810-1/8 Standard plug depth P2 2-1/82-9/163-3/164-1/165-3/167 -1/410 'Dupe: Thickness of tongue t 5/3213/64 1/4 5/1615/325/8 3/4 1-1/8 Length of tongue T 1/4 3/8 7/16 9/165/8 3/4 1-1/81-3/8 Diameter of tongue d .235 .343 17/32 23/3231/321-13/322 2-5/8 Keyway: Width of keyway W .160 .213 .260 .322 .478 .635 .7601.135 Length of keyway L 9/16 3/4 7/8 1-3/161-1/4 1-1/21-3/42-5/8 End of socket to keyway K1-15/162-1/16 2-1/23-1/163-7/84-15/167 9-1/2 Taper per foot .625 .600 .602 .602 .623 .t30 .626 .625 Taper per inch 05208 .05.05016.05016.05191 .0525.05216.05208 Number of key 0 1 2 3 4 5 6 7

28.138X Figure 9-2.-Morse tapers. importance. To illustrate, figure 9-5 shows two Suppose you want to turn a taperon the full very different tapers produced by thesame length of a piece 12 inches long withone end amount of setover of the tailstock, because for having a diameter of 3 inches, and the other end one taper the length of the work between a diameter of 2 inches. The small end is to be 1 centersisseater than for the other. THE inch smaller than the large end;so you set the CLOSER THE DEAD CENTER IS TO THE tailstock over one-half this amountor 1/2 Inch LIVE CENTER, THE STEEPER ISTHE in this example. Thus, atone end the cutting TAPER PRODUCED. tool will be 1/2 inch closer to thecenter of the

9-4 Chapter 9ADVANCED ENGINELATHE OPERATIONS

28.141X Figure 9-5.Setover of talistock showingimportance of considering length of work.

Remember that L is the length of the work from live center to deadcenter. If the work is on 29.139128D1X a mandrel, L is the length of the mandrel Figure 9-3.Tellstock setover lines fortaper turning. between centers. You cannotuse the setover tailstock method for steep tapersbecause the setover would be too great and the workwould work than at the other end;so the diameter of not be properly supported by the lathecenters. the finished job will be ,2 X 1/2or 1 inch less at It is obvious that with setoverthere is not a true the small end. Since the piece is 12inches long, bearing between the work centers andthe lathe you have produced a taper of 1 inchper foot. center points and the bearing surfacebecomes Now, if you wish to producea taper of 1 inch less andlesssatisfactoryasthe setover is per foot on a piece only 6 inches long, the small increased.CAUTION: DO NOT EXCEED end will be only 1/2 inch less indiameter than .250-inch setover. the larger end, so you shouldset over the tailstock 1/4 inch or one-half ofthe distance After turning a taper by the tailstocksetover used for the 12-inch length. method, do not forget to realignthe centers for By now you cansee that the setover is straight turning of your next job. proportional to the length betweencenters. Setover is computed by the following formula: Using the Compound Rest T L S = X 2 12 The compound rest is generallyused for short, steep tapers. Set it at theangle the taper is where: S = setover in inches to make with the centerline (thatis, half the T = taper per foot in inches included angle of the taper).Then feed the tool -ry = length in foot of taper to the work at this angle by thecompound rest feed screw. The length oftaper you can machine is necessarily short becauseof limited travel of the compound rest top. Truing a lathe center isone example of using the compound restfortaper work. Other examples are refacingan angle type valve disk, machining the face ofa bevel gear, and similar work. Such jobs are often referredto as working to an angle rather than as taper work. The graduations markedon the compound 28.140X rest are a quick means for setting itto the angle Figure 9-4.Measuring mover of deadcenter. desired. When set atzero, the compound rest is

9-5 MACHINERY REPAIRMAN 3 & 2

perpendicular to the lathe axis. When setat 90° movement of ,the cross-slide. Set the guide bar on either side, the compound rest is parallel to for the taper desired; the attachment is ready for the lathe axis. operation. The final adjustment of the toolfor On the other hand, when the angle to becut size must be made by means of the compound is measured from the centerline, the settingof rest feed screw, since the crossfeedscrew is thecompoundrestcorrespondstothe inoperative. complement of that angle (the complementof There will be a certain amount of lost an angle is that arg,:e which added to it makesa motion or backlash when the tool first startsto rightangle;thatis,angleplus. feed along the work. This is caused bylooseness complement = 90°). For example, tomachine a between the crossfeedscrew and the cross-slide 50°includedangle(25°anglewiththe nut. If the backlash is not eliminated,a straight centerline), set the compound rest at 90°- 25°, portion will be turned on the work. Youcan or 65°. remove the backlash by moving the carriage and tool slightly past the start of the cut andthen Whenaveryaccuratesetting of the returning the carriage and tool to the start of the compound rest is to be made toa fraction of a cut. degree for example, run the carriageup to the faceplate and set the compoundrest with a vernier bevel protractor set to therequired TAPER BORING angle. Hold the blade of theprotractor on the flat surface of the faceplate and hold thebase of the protractor against the finished side ofthe Taper boring is usually done with either the compound rest. compound rest or the taper attachment.The rules that apply to outside taper turningalso For turning and boring longtapers with apply to the boring of taper holes. Begin by accuracy, the taper attachment is indispensable. drilling the hole to the correct depth witha drill It is especially useful in duplicatingwork; you of the same size as the specified small diameter can turn and bore identical tapers withone of the taper. This givesyou the advantage of setting of the taper guide bar. Set theguide bar at an angle to the lathe which correspondsto the desired taper. The tool cross-slide isthen moved laterally by a shoe which slideson the guide' bar asthecarriagemoves longitudinally. The resulting movement of the cutting tool'isalong a linethatisparalleltothe guide bar, and therefore a taper is produced whoseangular measurement is the same as that seton the guide bar. The guide bar is graduated indegrees atone end and in inches per foot oftaper at the other end to facilitate rapid setting. Figure9-6 is view of the end that is graduated ininches per foot of taper.

When preparing to use the taper attachment, run the carriage up to the approximate position of the work to be turned. Set thetool on line with the centers of the lathe. Thenbolt or clamp the holding bracket to theways of the bed (the attachment itself is bolted to the backof the carriage saddle) and tighten clamp C, figure9-7. The taper guide bar 28.142X now controls the lateral Figure 9.8.End view oftaper guide bar.

9-6 2.)h, Chapter 9ADVANCED ENGINE LATHEOPERATIONS

OL.

28.143X Figure 9.7.Turning a taper usingtaper attachment. boringtotheright size without having to 2. Rub the gage lightly withchalk (or remove metal at the bottom of the bore, which prussian blueif the width must be highly is rather difficult, particularly in small,deep accurate). holes. 3.Insert the gage into the hole andturn it For turning and boring tapers,set the tool SLIGHTLY so that the chalk (or prussianblue) cutting edge exactly at the center of rubs from the gage onto the surfaceof the hole. the work. If the workpiece is to be mounted That is, set the point of the cutting edgeeven on a spindle, with the height of the lathecenters; otherwise, use the tapered end of the spindle instead ofa the taper may be inaccurate. gage to test the taper. 4.Areas that do not touch thegage will be Cut the hole and measure its size andtaper shown by a lack of chalk (or prussianblue). using a taper plug gage and the "cut and try" 5.Continue making minor correctionsuntil method: all,or an acceptable portion, of the hole's surface touches thegage. Be sure the taper 1.After you have takenone or two cuts, diameter is correct beforeyou turn the taper to clean the bore. its finish diameter.

9-7 29s MACHINERY REPAIRMAN 3 & 2

to increase mechanical advantage and to provide good clamping ability as in thescrew jack or vise screw. Each of these screw forms is discussed more fully later in the chapter.

There are several terms used in describing aMEI1111110 screw threads and screw thread systems which you must know before you can calculate and 28.144X machine screw threads. Figure 9-9 showsthe Figure 9-8.Morse taper socket gage and pluggage. application of some of the followingterms: EXTERNAL THREADS: A threadon the Figure 9-8 shows a Morse standardtaper external surface of a cylinder. plug and a taper socket gage. They not only give the proper taper, but also show theproper INTERNAL THREAD: A threadon the distance that the taper should enter thespindle. internal surface of a hollow cylinder.

RIGHT-HAND THREAD: A thread which, SCREW THREADS when viewed axially, winds ina clockwise and receding direction. Much of the machine work performed bya Machinery Repairman includes theuse of screw LEFT-HAND THREAD: A thread threads. The thread forms which, you will be working when viewedaxially,windsin a with most are V-form threads,Acme threads, counterclockwise and receding direction. and square threads. Each of these threadforms is used for specific purposes. V-form threadsare LEAD: The distance a threadedpart moves commonly used on fastening devices suchas axially in a fixed mating part inone complete bolts and nuts as well ason machine parts. revolution. Acme screw threads aregenerally used for transmitting motion, such as between the lead PITCH: The distance between corresponding screw and lathe carriage. Square threadsare used poitts on adjacent threads.

CREST FLANKS PITCH ROOT

I- thi AXIS X OF \1111 4 THREAD a

R 111 EN ar 'Ur 60 PITCH THREAD ANGLE EXTERNAL THREAD INTERNAL THREAD

28.145(28D) Figure 9-9.Screw thread nomenclature.

9-8 Chapter 9ADVANCED ENGINELATHE OPERATIONS

SINGLE THREAD: A single (singlestart) MINOR DIAMETER: The diameter of thread whose lead equals the pitch. a cylinder that bounds the root ofan external thread or the crest of an internal thread. MULTIPLE THREAD: A multiple (multiple start)threadwhoseleadequals thepitch HEIGHT OF THREAD: The distancefrom multiplied by the number of starts. the crest to the root ofa thread measured perpendicular to the axis of the threadedpiece CLASS OF THREADS: Classes ofthreads (also called straight depth of thread). are distinguished from each other by the amount of tolerance and allowance specified. SLANT DEPTH: The distance fromthe crest to the root of a thread measured alongthe angle THREAD FORM: The axial plane profileof forming the side of the thread. a thread for a length of one pitch. ALLOWANCE: An intentional difference FLANK: The side of the thread. between the maximum material limits ofmating parts.Itis the minimum clearance (positive CREST: The top of the thread (boundedby allowance) or maximum interference the major diameter (negative on external threads; by the allowance) between such parts. minor diameter on internal threads). TOLERANCE:Thetotalpermissible ROOT: The bottom of the thread (bounded variation by the minor diameter of asize.The toleranceisthe on external threads; by difference between the limits of size. the major diameter on internal threads). THREAD FORM SERIES: Threadsare THREAD ANGLE: The angle formedby made in many different adjacent flanks of a thread. shapes,sizes, and accuracies. When special threadsare required by the product designer, he will specify PITCH DIAMETER: The diameter in detail all of an the thread characteristics andtheir tolerances imaginary cylinder that is concentricwith the for production information. When thread axis and whose periphery a standard passes through thread is selected, however, he needsonly to the thread profile at the pointwhere the width specifysize,number of threads per inch, of the thread and the threadgroove are equal. designation of the standard series The pitch diameter is the diameter and the class which is offit.Withthisspecification,allother measured when 'le thread is machinedto size. A informationnecessaryforproduction is change in pitch diameter changesthe fit between obtainedfrom theestablished standard,as thethread being machined and themating thread. published. The abbreviated designationsfor the different series are as follows: NOMINt3IZE: The size which is used for .1. or example, the nominal size of Abbreviation Full Title of Standard Series a 1/2-1u thread is 1/2 inch, but its actual size is slightly smaller to provide clearance. UNC Unified coarse thread series ACTUAL SIZE: The measured size. UNF Unified fine thread series

BASIC SIZE: The theoretical size. Thebasic UNEF Unified extra fine thread series size is changed to provide the desiredclearance or fit. NC AmericanNationalcoarse thread series MAJOR DIAMETER: The diameterof a cylinder that bounds the crest ofan external NF thread or the root of an internal thread. American National fine thread series MACHINERY REPAIRMAN 3 & 2

Abbreviation Full Title of Standard Series American National and The American Standard unified. MI of these threads have a 60° included NEF American National extra fine angle between their sides. The V-sharp thread thread series has a greater depth than the others and the crest UN and root of this thread have little orno flat. The Unified constant pitch series external American Standard unified thread has including 4, 6, 8, 12, 16, 20, slightly less depth than the external American 28, and 32 threads per inch National thread Cliit is otherwise similar. The NA AmericanNationalacme American Standard unified thread is actuallya thread series modification of the American National thread. This modification was made so that the unified NPT AmericanNationaltapered seriesofthreads,whichpermits pipe thread series interchangeabilityofstandardthreaded fastening devices manufactured in the United NPS AmericanNationalstraight States, Canada, and the United Kingdom, could pipe thread series be included in the threading system used in the United States. The Naval Sea Systems Command NH AmericanNationalhose and naval procurement activities use American coupling thread series Standard unified threading system specifications whenever possible; this system is recommended NS AmericanNationalform for use by all naval activities. thread-special pitch To cut a V-form screw thread, you need to N BUTT National Buttress Thread know (1) the pitch of the thread, (2) the straight depth of the thread, (3) the slant depth of the THREAD DESIGNATION: A threadis thread, and (4) the width of the flat at theroot designated according to the nominal size, the of the thread. The pitch of a thread is the basis number of threads per inch, the series6.ibol, for calculating all other dimensions and is equal andthe classsymbol,inthatorder.. For to 1 divided by the number of threadsper inch. example, the designation1/4-20 UNC-3A is The basis for determining the bore diameter is: explained as follows: minor diameter of the nut equals the major diameter of the externally threaded part minus 1/4 = nominal thread diameter 1.0825 divided by the number of threadsper inch: 20 = number of threads per inch

UNC = series (Unified coarse) Boresize 1.0825 N 3 = class

A = external thread When the thread cutting tool is fed into the workpiece at one-half of the included angle of Unless the designation LH (left hand) follows thethread, the slant-depthis the dimension the class designation, the thread is assumed to be necessary to determine how far to feed the tool aright-handthread.An exampleofthe into the work. The point of the threading tool designation for a left-hand thread is:1/4-20 must have a flat equal to the width of the flat at UNC-3A-LH. the root of the thread (externalor internal thread, as applicable). If the flat at the point of V-FORM THREADS the tool is too wide, the resulting thread will be too thin if the cutting tool is fed in the correct The three forms of V-threads thatyou must amount. If the flat is too narrow, the thread will know how to machine are the V-sharp, the be too thick.

9-10 Chapter 9ADVANCED ENGINELATHE OPERATIONS The following formulas will provide the (NOTE: MULTIPLYING theconstant by informationyou needforcuttingV-form threads: the pitch, as in the preceding formulas,produces the same result as ifyou divide the cone Int by 1. V-SHARP THREAD. the number of threadsper inch.) To produce the correct threadprofile, you must use Pitch = --1-1 or 1 ÷ nun.ber ofthreads per tool accurately ground to thecorrect inch angle and contour. Also,you must set the cutting tool in the correct position. Figure9-10 Straight Depth of thread= 0.886 X pitch shows how a tool must be ground andset. You must grind the point of the tool 2. AMERICAN NATIONALTHREAD. to an angle of 60°, as shown in A of figure9-10. Use a center gage or a thread-tool Pitch = 1 ÷ number of threadsper inch gage for grinding the tool to the exact angle required.The top of the or--1 n tool is usually ground flat, withno side rake or Straight depth of external back rake. However, for cuttingthreads in steel, thread = side rake is sometimes used. 0.64952 X pitch or 0.64952p Straight depth of internalthread = Set the threading tool 0.541266 X pitch or 0.541266p square with the work, Width of flat as shown in B and C of figure 9-10. Usethe at point of tool for center gage to adjust the point of the external and internal threads= 0.125 threading X pitch or 0.125p tool; if you carefully set thetool, a perfect threadwillresult. Slant depth of external thread= 0.750 X If you do not set the pitch or 0.750p threading tool perfectlysquare with the work, the angle of the thread will be incorrect. Slant depth of internal thread= 0.625 X pitch or 0.625p For cutting external threads,place the top 3. AMERICAN STANDARDUNIFIED. of the threading tool exactlyon center as shown in D of figure 9-10. Note that thetop of the tool Pitch = 1 ÷ number ofthreads per inch is ground flat and is in exactalignment with the or1 lathe center. This isnecessary to obtain the correct angle of the thread. Straight depth of externalthread = 0.61343 inch X pitchor 0.61343p Size of the threading tool forcutting an Straightdepth of internalthread rote;: ial thread is important. Thetool head must 0.54127 inch X pitch= 0.54127p be ...uall enough to be backedout of the thread Width of flat at root of externalthread andtill leave enough clearance to bedrawn 0.125 inch X pitchor 0.125p from the threaded hole withoutinjuring the Width of flat at crest of externalthreads threrk,. However, the boring bar which holdsthe = 0.125 inch X pitch or 0.125p threadi)1 tool for internal threadingshould be Width of flat at root of internalthread = bot% as large fr, possible in diaineterand as short 0.125 inch X pitchor 0.125p as r. ;,) prevent its springingaway from Width of flat at crest of internalthread = the .vork e,0 0.25 inch X pitch or 0.25p pouble height of externalthread = 1.22687 inch X pitchor 1.22687p 0 7111E: l',21.7 THREADS Doubleheight of internalthread = 1.08253 inch X pitchor I.08253p As stated p t..y, Slant depth of external thread the cutting tool is = 0.708 X ground to the fon.)f the thread desired. In the pitch or 0.708p %Jo dingsection Slant depth of internal thread Acme and squarescrew = 0,625 X threadsareill,.:stratedwithpertinent pitch or 0.625p ?piontiation on cutting these thread3. 9.11 r 11.1111111111111MMANdeartiay,;7421111111i1 MACHINERY REPAIRMAN 3 & 2

FORMULAS PITCH (M No. Threads per inch A DEPTH (011/2 P+0.010" SLANT DEPTH0.516P+0.010" CREST (C) 03707 P ROOT (R)0.3707 P-0.0052"

28.147X Figure 9-11.Acme thread and formulas for cutting.

bottom of the threads have an included angle of 29° (fig. 9-11). I Parts A and B of figure 9-12 show the method of setting an Acme threading tool for cutting an external and internal Acme thread, respectively. Note that a 29° Acme thread gage is used in the same manner as Abe center gage was used for V-form screw thread,: Adjust the cutting edge of the tool to line it up exactly with the beveled edge of the gage. The notches in the Acme thread gage let you grind the squared front edge of the tool bit accurately in C accordance with the pitch of the thread to be machined.

In cutting an Acme thread, besure the clearance is 0.010 inch between the top of the

28.148X Figure 9.10. Threading tool setup for V-form threads.

The Acme Screw Thread The Acme screw thread is used on valve stems, the lead screw of a lathe, and other places 28.148X that, require a strong thread. The top and Figure 9-12.Uso of Acme thread tool gage.

9-12 24 3 Chapter 9ADVANCED ENGINELATHE OPERATIONS thread of the screw and thebottom of the thread of the nut in whichfits.

The Square Thread ICREST The square thread (fig.9-13) is used when H heavy threads are required, suchas in jack screws, press screws and feedscrews. It is used DEPTH for much the samepurpose as the Acme thread, which is used inmany places where the square thread was formerly used. Thedisadvantage of square threads is that the straightsides do not allow sideplay adjustment. The cutting edge widthof the tool for ROOT cutting square screw threads isexactly one-half RADIUS the pitch, but the width ofthe edge of the tool for threading nuts is from 0.001 28.350 to 0.003 inch Figure 9-14.Buttress thread. larger. This permits a sliding fiton the screw. Set the threading tool forcutting square threads square with the work.Since the edge of the tool is square, American Standard form of thebuttress thread you need to adjust only the has a 7° angle on the edge to the surface of the work. pressure flank; other forms Be sure the clearance between have 0°, 3°, or 5°. However,the American the top of the Standard form is most oftenused, and the thread of the screw and thatof the bottom of formulas in this section apply the thread of the nut is about 0.005to 0.008 to this form. The inch for each inch of thread buttress thread can be designedto either push or diameter. pull against the internalthread of the mating part into which it is served. Thedirection of this thrust will determine the BUTTRESS THREAD way you grind your tool for machining the thread.An example of thedesignationsymbolsforanAmerican On a buttress thread (fig.9-14) the load Standard Buttress thread resisting sideisnearly perpendicular to the form are as follows: thread axis and is called thepressure flank. The 6 - 10 (4--N BUTT-2

where 6 = basic major diameterof 6.00U inches

10 = 10 threadsper inch

(4-- =internal member to pushagainst external member FORMULAS N BUTT = National PITCH(P)= Buttress Form No. Threads per Inch DEPTH (D)= P x 0.500"+ 0.005" to 0.008" 2 = class of fit SPACE(F):: Px 0.500" NOTE: A symbol suchas "+-(" indicates 28.149X that the internalmember is to pull againstthe Figure 9.13. Square thread and formulas. external mem ber. '" 2 MACHINERY REPAIRMAN 3 & 2

The fomulas for the basic dimensionsof the The designation of pipe threads is expressed American Standard Buttress external threadare as follows: as follows: NPT 1/418 Pitch = n where NPT = tapered pipe thread

Width of flat at crest = 0.1631 X pitch 1/4 = inside diameter of thepipe in inches Root radius = 0.0714 X pitch 18 = threadsper inch Depth of thread = 0.6627 X pitch Figure 9-15 shows the typical dimensionsof the most common tapered pipe threads. The classes of fit are: 1 = free, 2= medium, 3 = close.The specificdimensions involved apply to the tolerance to the pitchdiameter and STR HT PIPE THREADS the major diameter andvary according to the nominal or basic size. Consult a handbook for Straight pipe threads are similar in formto specific information on the dimensionsfor the the tapered pipe thread except that they various classes of fit. are not tapered. The same nominal outside diameterand thread dimensions apply. Straight pipe threads are used for mechanically joining components andarenotsatisfactoryfor PIPE THREADS high-pressure applications. Sometimes a stight pipe thread is used with a tapered piperead to form a low- pressuresea 1 inavibrationfree American National Standard Pipe threadsare environment. similar to the unified threads in that bothhave an included angle of 60° and a flat on the crest and the root of the thread. Pipe threadscan be CLASSES OF THRE either tapered or straight, dependingon the intended use of the threaded part. A description Classes of fit for threads are de rmined by of the two typesis given in the following the amount of tolerance and allowan,allowed paragraphs. for each particular class. The tolerance unt thatathread may varyfromthebasic dimension)decreasesastheclass number TAPERED PIPE THREADS increases. As an example, a class 1 threadhas more tolerance than a class 3 thread. The pitch diameter of the thread is themost important Tapered pipe threads are used to providea thread element in controlling the classof fit. pressuretight joint when theinternal and The major diameter for external mating parts an external thread and are assembled correctly. the minor diameter or bore size foran internal Depending on the closeness of the fit ofthe thread are also important, however, since, mating parts, you may need to they use a sealer (pipe control the crest and root clearancesmore than compound) to prevent leakage at the joint.The the actual fit of the thread. A brief description taper of the threads is 3/4 inchper foot. of the different classes of fitare as follows: Machine and thread the section of pipeto be threaded at this angle. The hole for the internal Classes IA and 1B: Class IA for external threads should be slightly larger than the minor threads and 1B for internal threadsare used on diameter of the small end of theexternal threaded components where quick and threaded part. easy assemblyisnecessary and where aliberal 9-14 Chapter 9-ADVANCED ENGINELATHE OPERATIONS

LENGTH OP IMPERFECT EFFECTIVE THREAD THREADS FOR ALL DIMENSIONS SEE Ale CORRESPONDING REFERENCE LETTERS Ai BELOW.

I I ANGLE BETWEEN SIDES OF THREADIS 60°. TAPER OF THREAD, ON DIAMETER, IS INCH PER FOOT.

THE BASIC THREAD DEPTH IS 0.8X PITCH OF THREAD AND THE CREST AND ROOT ARE TRUNCATEDAN AMOUNT EQUAL TO 0.039 X PITCH. EXCEPTING 8 THREADS PER INCHWHICH HAVE A BASIC DEPTH OF 0.708 X PITCH AND ARE TRUNCATED0.045 X PITCH AT THE CREST AND 0.033 X PITCH AT THE ROOT.

PIPE SIZE PITCH DIAMETER, x ,_ I- o o ONO u 0>0 F., z X z 4N_, w ce cc 4z u...., u. _, ocsta t5) uci.,_ IA., zeui dui WW ww- 040 040 vc1, xl:-..E wo 4 04 0.-1 6..1 =N C"--OW , ,.4 'La X iw CO X cc 0 Z 4 Ocl t; (109 fru, 1-cr4 W ..J -I azw zww zwwcr w zu-x 4 taw xce cra rc4 G ....zo 3., a.z20.. ,...0z 52 a Ox z _Aw -,. I_. a.111 UT Z rl," o b- ,.. x 1- 1- . 1- W42-Jy xi- 0 D., ' 4 W 4- 51-4 21-4 A is ------_____ F j____.-E."- --.\C D w-- K 0 H 1/8 0.405 27 /NT' 0.36351 0.37476 0.2638 0.180 0.1285 0.02963 0.03704 0.334 0.39 1/4 0.540 -...... 18 0.47739 0.48989 0.4018 0.200 0.1928 0.04444 0.05556 O. 433 O. 52 8 0.675 . 18 . 201 0.62701 0.4078 0.240 0.1928 0.04444 0.05556 0.568 0.65 1/2 0.840 14 0.75 3 0.77843 0.5337 0.320 0.2478 0.05714 0.07143 0.701 0.81 3/4 1.050 14 0.96768 0.98887 0.5457 0.339 0.2478 0.05714 0.07143 0.911 0.02 I 1.315 104 1.21363 1.23863 0.682U 0.400 0.3017 0.06957 0.08696 1,144 1.28

28.351 Figure 8.16. -Taper pipe threaddimensions.

allowance is required to permitready assembly, Tables of the basic dimensions even with slightly bruised or dirty and the threads. maximum and mininiudimensions for each size and class c'at of t Classes 2A and 2B: Class 2A for eads are found in most external publications and hand ics for machinists. An threads and 2B for internal threadsare the most example. ofthe commonly used thread standards mensionsrequiredto for general accurately machinespecific class of fit ona applicationsincluding productionofbolts, thread is shown in Table 9-2. screws, nuts and similar threaded fasteners.

Classes 3A and 3B: Class 3A forexternal MEASURING SCREW THREADS threads and 3B for Internal threadsprovide for applications where closeness offit and accuracy of lead and angle of thread are important. They Thread measurement is needed are obtainable consistently only by high to ensure quality that the thread and its matingpart willfit production methods,witha veryefficient properly. It is important that system of gaging and inspection. you knovV the various measuring methods and thecalculations 9-15 MACHINERY REPAIRMAN 3 & 2

Table 9.2. Classes of Fit and Tolerances for 1/4-20 LAC Thread

1/4-20 UNIFIED SCREW THREAD (13XTERNAD

._ Basic MaximumMinimum Basic MaximumMinimum Major Major/ Major Pitch Pitch Pitch Designation Diameter Diameter \*"-Diameter Diameter Diameter Diameter 1/4- 20 UNC-1A 0.250 0.2489 0.2367- 0.2175 0.2164 0.2108 1/4-20 UNC-2A 0.250 0.2489 0.2408 0.2175 0.2164 1 /4-20 UNC-3A 0.2127 0.250 0.2500 0.2419 0.2175 0.2175 0.2147 1 /4- 20 UNIFIED .SCREW THREAD(INTERNAL)

Basic MaximumMinimum Minor Minor Minor Basic MaximumMinimum Diameter Diameter Diameter Pitch Pitch Designation Pitch (Bore Size)(Bore Size)(Bore Size)Diameter Diameter Diameter '1/4-20 UNC-1B 0.1876 0.196 0.207 0.2175 0.2248 0.2175 1/4-20 UNC-2B 0.1876 0.196 0.207 0.2175 0.2223 1/4-20 UNC-3B 0.2175 0.1887 0.196 0.2067 0.2175 0.2211 0.2175 28.352 which are used to determine the dimensions of same size ranges as ordinary micrometers: 0 to 1 threads. inch, 1 to 2 inches, etd. In addition, theyare \The use of a mating part is common practice available in various pitch ranges. The number Of when average accuracy is required. The thread is threads per inch must be within the pitchrange simply machined until the mating part will of the thread. assemble. A snug fit is usually desired withvery little, if any, play between the parts. RING AND PLUG GAGES You will sometimes oe required to machine threads that need a specific class of fit, or you Go and,, no-go gages, such as those shown in. may not have the mating part to use as a gage. lir figure 9-17, are often used to check threaded these cases, you must use a method of measuring parts. The ead should fit the-"go" portion of the thread to make sure ; cu get the required fit. the gage, b tould not screw into or onto the An explanation of the various methods "no-go"orti . Ring and plug gages are normally availableto youisgiveninthe availahfor the various sizes and classes of fit of following paragraphs: thread: They--.1re probably the most, accurate ,1 method of threadsbecausethey envelop theotal thread form, and in effect, THREAD MICROMETER check ` bot only the pitch diameter, major and minor diameter, but also the lead of the thread. Thread micrometers are used to ineasu:':-. the pitch 'diameter of threads. They ire- graduated -THREE WIRE METHOD and readinthe same manner is ordinary micrometers. However, the anvil and spindleare The pitch diameter ofa thread can' be ground to the shape of a thread, 'as shown in accurately measured by an ordinary micrometer figure 9-16. Thread micrometerscome in the and three wires, as shown in figure 9-18. 21 9-16 Chapter 9ADVANCED ENGINELATHE OPERATIONS

THREAD

ANVIL

SCREW

28.353 Figure 9-16.Measuring threads witha thread micrometer.

The wire size you shoulduse to measure the pitch diameter dependsupon the number of threads per inch. The mostaccurate results are obtained when you use the "bestwire size." The DOUBLE END LIMIT PLUG THREAD GAGE best size is not always available,but you will get satisfactory results if youuse wire diameters

MICROMETER SCREW MEASURING WIRE

GO RING GAGE NO 00 RING GAGE

PITCH DIA MAJOR DIA

MEASUREMENT SCREW THREAD

MICROMETER ANVIL ADJUSTABLE THREAD SNAP GAGE

28.364 28.355 Figure 9-17.Thread gages. Figure 9- 18. Measuring threads using threewires.

9-17 MACHINERY REPAIRMAN 3 & 2

within a given range. Use a wire size as close as Now make the calculation. The data collected so possible to the best wire size. You can use these far are: formulas: Thread = 3/4-10 UNC - 2A

Best wire size = 0.57735 inch X pitch Pitch diameter (PD) = 0.6832 in.

Smallest wire size= 0.56 inch X pitch Pitch (P) = 0.100 in.

Largest wire size = 0.90 inch X pitch Wire size (W) = 0.0577 in.

The standard formula for the measurement For example, the diameter of the best wire for over the wires was M = PD - (0.86603 X P) + (3 measuring a thread that has 10 threads per inch X W). Enter the collected data in the correct is 0.577 inch, but you could use any size position of the formula: between 0.056 inch and 0.090 inch.

NOTE: The wires should be fairly hard and M = 0.6832 in.- (0.86603 in. X 0.100 in.) + uniform in diameter. All three wires must be the (3 X 0.577 in.) same size. You can use the shanks of drill bits as substitutes for the wires. M = 0.6832 in.- 0.086603 in. + 0.1731 in. Use the following formulas to determine M = 0.769697 in. what the measurement over the wires should be for a given pitch diameter. The measurement over the wires should be 0.769697 in. or when rounded to four decimal Measurement = pitch diameter- (0.86603 places, 0.7697 in. pitch) + (3 X wire diameter) As mentioned in the beginning of the section on classes of threads, the major diameter is a M = PD - (0.86603 X P) + (3 X W) factor also considered in each different class of fit. The basic or nominal major diameter is seldom thesizeactually machined on the outside diameter of the part to be threaded. The Use the actual size of the wires in the actual size is smaller than the basic size. In the formula, not the calculated size. case of the 3/4 - 10 UNC - 2A thread, the basic Example: What should the measurement be size is 0.750 in., however, the size that the over the wires for a 3/4-10 UNC-2A? First, y,.0 outside diameter should be machined is between must determine the required pitch diameter for 0.7482 and 0.7353 in. 2 :lass 2A 3/4-10 UNC thread. You can find this libitirmation in charts in several handbooks for machinists. The limits of the pitch diameter for HOW TO CUT SCREW this particular thread size and classare between THREADS ON A LATHE 0.6832 and 1...0773 in. Use the maximum size (0.6832 inch) for this example. Next,you must calculate the pitch for 10 threads per inch. The Screw threads are cut on the lathe by formula, "one divided by the number of threads connecting the headstock spindle of the lathe per inch" will give you pitch =,1 For 10 TPI, with the lead screw by a series of gears to geta positive carriage feed, and the leadscrew is the pitch is 0.100 in. As previously stated, the driven at the required speed in relation to the best wire size for measuring 10 TPI is 0.577 in., headstock spindle. You can arrange the gearing so assume that you have this wire size available. between the headstock spindle and lead screw so 2 Iri 'la 9-18 Chapter 9ADVANCED ENGINELATHE OPERATIONS that you can cut any c sired pitch of the thread. replace the lathe dog in thesame slot of the For example, if the ka.iscrew has 8 threads per driving plate. inch and youarrange the gears so that the When threading work in the lathechuck, be headstock spindle revolves fourtimes while the lead screw revolves sure the chuck jaws are tight and thework is once, the thread you cut will well supported. Neverremove the work from the be four times as fineas the thread on the lead screw,or chuck until the thread is finished. 32 threadsperinch.With the When threading long quick-change gear box, slender shafts, use a you can quickly and fol)r.wer rest. You mustuse the center rest to easily make the proper gearingarrangement by support one end of long work placing the levers as indicatedon the index plate that is to be for the thread desired. threaded on the inside. When you have the latheset up to control Position of Compound Rest the carriage movement forcutting the desired for Cutting Screw Threads thread pitch, your next considerationis shaping the ''tread. Grind the cutting tool to the shape Ordinarily on threads of fine required for the form of thethread to be cut, lead, you feed thatisV, Acme, the tool straight into the work insuccessive cuts. square,etc.Adjust the For coarse threads,it cross-slide to get the depth of thethread. is better to set the compound rest at one-half of theincluded angle of the thread and feed in Mounting Work in the Lathe along the side of the thread. For the last fewfinishing cuts, you should feed the toolstraightin When mounting workbetween lathe centers with the crossfeed of the lathe to makea smooth, even for cutting screw threads, besure the lathe dog finish on both sides of the thread. is securely attached beforestarting to cut the Incutting thread. If the dog should slip, V-formthreadsandwhen the thread will be maximum production is desired, ruined. Do notremove the lathe dog from the it is customary work until you have completed to place the compound rest ofthe lathe at an the thread. If angle of 29 1/2°,as shown in Part A of figure you must remove the workfrom the lathe 9-19. When you set the before the threadis completed, be compound rest in this sure to position and use the compoundrest screw to

DEPTH OF CUTN7g DIRECTION OF FEED

CUTTER BIT

B

28.150X Figure 9-19.Compound restset at 29 1/2°. 9-19 2,30 MACHINERY REPAIRMAN 3 & 2

adjust the depth of cut, you remove most of the metal by the left side of the threading tool (B of ADJUSTING fig. 9-19). This permits the chip to curl out of SCREW MICROMET ER the way better than if you feed the tool straight COLLAR WORK in, and it prevents tearing of the thread. Since the angle on the side of the threading tool is 30°, the right side of the tool will shave the thread smooth and produce a better finish; although it does not remove enough metal to

interfere with the main chip, which is taken by TNREADCUTTING the left side of the tool. STOP

28.151X Using the Thread-Cutting Stop Figure 9-20.Adjustable thread-cutting stop mounted on carriage saddle (clamped to dovetail). Because of the lost motion caused by the play. necessaryfor smooth operation of the Withdraw the tool by moving it toward the change gears, lead screw, half-nuts, etc,you center or axis of the lathe. must withdraw the thread-cutting tool quickly at the end of each cut. If you do not withdraw You can use the micrometer collar on- the quickly, the point of the tool will dig into the crossfeed screw in place of the thread-cutting thread and may break off. stop, if desired. To do this, first bring -the point To resetthetoolaccuratelyforeach of the threading tool up so that it just touches successive cut and to regulate the depth of the the work; then adjust the micrometer collaron chip, use the thread-cutting stop. the crossfeed screw to zero. All adjustments for First, set the point of the tool so that it just obtaining the desired depth of cut should be touchgt the work, then lock the thread-cutting made with the compound rest screw. Withdraw stop; turning th`e thread-cutting stop screw A the tool at the end of each cut by turning the **lg. 9-20) until thshoulder is tight againststop crossfeed screw to the left one complete turn; B (fig. 9-20). When you are ready to take the return the tool to the starting point, and turn first chip, run the tool rest back by turning the the crossfeed screw to the right one turn, crossfeed screw to the left several times, and stopping at zero. You can then adjust the move the tool to the point where the thread is compound rest feed screw for any desired depth. to start. Then, turn the crossfeed screw to the right until the thread-cutting stop screw strikes the thread-cutting stop. The tool is now in the Engaging the Thread Feed Mechanism original position. By turning the compound rest feed screw in 0.002 inch or 0.003 inch,you will have the tool in a position to take the first cut. When cutting threads on a lathe, clamp the For each successive cut after returning the half-nuts over the lead screw to engage the carriage to its starting point, you. can reset the threading feed and release at the end of the cut tool accurately to its previous position. Turn the by means of thethreadinglever. Use the crossfeed screw to the right until the shoulder of threading dial (discussed in chapter 7 of this screw A strikes stop B. Then, you can regulate training course and illustrated in fig. 7-37) to the depth of the next cut by adjusting the determine when to engage the half-nuts so that compound rest feed screw as it was for the first the cutting tool follows the same path during chip. each cut. When an index mark on the threading For cutting an internalthread,set the dial aNgns with the witness mark on its housing, adjustable thread-cutting stop with the head of engage the half-nuts. For some thread pitches, the adjusting screw on the inside of the stop. however, you can engage the half-nuts only

9-20 231 Chapter 9ADVANCED ENGINE LATHEOPERATIONS

when certain index marks are aligned with the witness mark. On most lathesyou can engage the half-nuts as follows:

For all even-numbered threadsper inch, close the half-its at any line on the dial. For all odd-numbered threadsper inch, close the half-nuts at any numbered lineon the dial. For all threads involving one-half of a thread 28.153X in each inch, such a 11 1/2, close the half-nutsat Figure 9-22.Screw pitch gage. any odd-numbered line.

Cutting the Thread Make the final check for bothdiameter and pitch of the thread with the nut that isto be used or with a ring threadgage, if one is After setting up the lathe,as explained available. The nut should fit snugly previously, take a very light trial cut just without play deep or shake but should not bind on the threadat enough to scribe a line on the surfaceof the any point. work, as shown in A of figure 9-21. Thepurpose of this trial cut is to besure that the lathe is arranged for cutting the desired pitch of thread. Lubricants for Cutting Threads To check the number of threadsper inch, place a rule against the work,as shown in B of figure 9-21, so that the end of the rulerests on To produce a smooth thread in the point of a thread or steel, use on one of the scribed lard oil as a lubricant. If oil isnot used, the lines. Count the scribed lines between the end of cutting tool will tear the steel, and the finishwill the rule and the first inch mark. This willgive ' be very rough. the number of threads per inch. It is quite difficult to accuratelycount fine If lard oilisunavailable, use any good pitches of screw threads. Ascrew pitch gage, cutting oil or machine oil. Ifyou experience usedasillustratedinfigure9-22,isvery trouble in producing a smooth thread,add a convenient for checking the finerscrew threads. little powdered sulfur to the oil. The gage consists of a number of sheet metal Apply the oil generously before eachcut. A plates in which are cut the exact form ofthreads small paint brush is ideal for applying of the various pitches; each plate is the oil stamped when cutting external screw threads.Since lard with a number indicating the number ofthreads oil is quite expensive, per inch for which it is to be used. many machinists place a small tray or cup just below the cuttingtool on the lathe cross-slide to catch thesurplus oil which drips off the work.

Resetting the Tool or Picking Up the Existing Thread

If the thread-cutting tool needsresharpening A B or gets out of alignment or if youare chasing the threads on a previously threadedpiece, you must reset the tool so that it will followthe 28.162X original thread groove. To reset thetool, (1) use Figure 9-21.The first cut. the compound rest feedscrew and crossfeed

9-21 MACHINERY REPAIRMAN 3 & 2

screw to jockey the tool to the proper position, If it is inconvenient to use the compound (2) disengage the change gears and turn the rest for readjusting the threading tool, loosen spindle until the tool is positioned properly,or the lathe dog (if used); turn the work so that the (3) loosen the lathe dog (if used) and turn the threadingtoolwill match the groove, and work until the tool is in proper position with the tighten the lathe dog. If possible, however, avoid thread groove. Regardless of which methodyou the necessity of doing this. use,youwillusuallyhavetoresetthe Another method, which is sometimes used, micrometer collars on the crossfeedscrew and is to disengage the reverse gears or the change the compound rest screw. gears; turn the headstock spindle until the point Before adjusting the tool in thegroove, use of the threading tool enters thegroove in the the appropriate thread gage to set the tool work, and then engage the gears. square with the workpiece. Then with the tool a few thousandths of an inch away from the Finishing the End workpiece, start the machine andengage the of a Threaded Piece threading mechanism. When the tool has moved to a position such as shown in figure 9-23, stop The end of a thread may be finished byany thelathewithoutdisengagingthethread one of several methods. The 45° chamfer on the mechanism. end of a thread, as shown in A of figure 9-24, is The most practical and commonly used commonly used for bolts and capscrews. For methodforresetting a threadingtoolfor machined parts and special screws, the end is machining ...angularformthreadsisthe often finished by rounding witha forming tool, compoundrestandcrossfeedpositioning as shown in B of figure 9-24. method. By adjusting the compound rest slide It is difficult to stop the threading tool forward or backward, you can move the tool abruptly, so some provision is usually made for laterally to the axis of the workas well as clearance at the end of the cut. In A of figure toward or away from the work. When the point 9-24, a hole has been drilled at the end of the of the tool coincides with the original thread thread; in B of figure 9-24, a neck orgroove has groove (see phantom view of tool in fig. 9-23), been cut around theshaft. The groove is use the crossfeed screw to bring the tool point preferable, as the lathe must be run very slowly directly into the groove. When you geta good fit to obtain satisfactory results with the drilled between the cutting tool and threadgroove, set hole. the micrometer collar on the crossfeedscrew on zero and set the micrometer collar on the LEFT-HAND SCREW THREADS compound rest feed screw to the depth of cut previously taken or to zero, as required. (Note: A left-handscrew(fig.9-25)turns Be sure that the thread mechanism is engaged counterclockwise when advancing (looking at and the tool is set square with the work before the head of the screw), or just the opposite toa adjusting the position of the tool along the axis right-hand screw. Left-hand threads are used for of the workpiece.) the crossfeed screws of lathes, the left-hand end

45°

FINISHING END OF THREAD FINISHING END OF THREAD WITH 45° CHAMFER WITH FORM TOOL

28.154X 28.156X Figure 9-23.Tool must be reset to original groove. Figure 9-24.Finishing the end of a threaded piece.

9-22 Chapter 9ADVANCED ENGINE LATHEOPERATIONS

MULTIPLE SCREW THREADS

A multiple thread, as shown in figure 9-27,is a combination of two or more threads, parallel to each other, progressing around the surface into which they are cut. Ifa single thread is 28.156X thought of as taking the form ofa helix, that is, Figure 9-25.A left-hand screw thread. of a string or cord wrapped arounda cylinder, a multiple thread may be thought ofas several cords lying side by side and wrapped arounda of axles, one end of a turnbuckle,or wherever cylinder. There may beany number of threads, an opposite thread is desired. and they start at equally spaced intervals around For cutting a left-hand threadon a lathe, the a cylinder. Multiple threads are used when rapid directionsarethesameasforcutting a movement of the nut or other attached parts is right-handthread,exceptyouswivelthe desired and when any weakening of the threadis compound rest to the left instead ofto the right. to be avoided. A single thread having thesame Figure 9-26 shows the correct positionfor the lead as a multiple thread would bevery deep in compound rest. The direction of travelfor the comparison to the multiple thread. The depth of tool differs from a right-hand thread inthat it the thread is calculated according to the pitch of moves toward the tailstock as the thread is being the thread. cut. Thetoolselectedforcuttingmultiple threads has the same shape as that of the thread Before starting to/cut a left-hand thread,it is to be cut and is similar to the tool used for good practice, if feasible, tocut a neck or groove cutting a single thread except that greater side in the workpiece. (See fig. 9-25.) Sucha groove clearance is necessary. The helix angle of the facilitates running the tool in for eachpass, in thread increases with an increase in the multiple the same manner as fora right-hand thread. thread. The general method for cutting multiple threads is about the sameas for single screw threads, except that the lathe must be gearedto DIRECTION OF TOOL TRAVEL the number of single threadsper inch, or with reference to the lead of the thread, and not the pitch, as shown in figure 9-27. Provisionsmust also be made to obtain the correct spacing of the different thread grooves. Youcan get the proper spacing by using the thread-chasing dial, setting the compound parallel to theways, using a faceplate, or using the change gear breakup.

LEAD LEAD PITCH LEAD PITCH PITCH ditt M

11411411NM*111 SINGLE THREAD DOUBLE THREAD TRIPLE THREAD

28.357 28.368 Figure 9-27.Comparison of single and multiple-lead Figure 9-26.Setup for left-hand external threads. threads.

9-23 254 MACHINERY REPAIRMAN 3 & 2 The use of the thread-chasing dial is the most desirable method for cutting 60° multiple threads. With each setting for depth of cut with the compound, youcan take successive cuts on each of the multiple threads so thatyou can use thread micrometers.

To explore the possibility of usingthe FOR FIRST THREAD, SPLIT FOR SECOND THREAD. SPLIT thread-chasing dial, you must first find out ifthe NUT CLOSED AT POINT "a" NUT CLOSED AT POINT1," lathe can be geared to cuta thread having a lead equal to that of one of the multiple threads.For example, if you want to cut 10 threadsper inch, double threaded, you divide the numberof threads per inch by the multiple (in thiscase 10/2) to get the number of single threadsper inch (in this case 5). Thenyou gear the lathe for TOOL IN LINE the number of single threadsper inch. TOOL IN LINE FOR FOR FIRST THREAD SECOND THREAD To use the thread-chasing dialon a specific machine, you should refertoinstructions 28.358 usually found attached to the lathe apron. If, for Figure 9-28.Cutting multiple threads using thethread- 5 threads per inch, you shouldengage the chasing dial. half-nut at any numbered lineon the dial, the same thread would be cut at positions 1 and 2 on the dial, as shown in figure 9-28. If you then The faceplate method of cuttingmultiple cover the dial with your hand, leaving the part threads involves changing the position ofthe uncovered between those adjacent positionsthat work between centers for eachgroove of the cut the groove (positions 1 and 2 in figure 9-28), multiple thread. One method is to cut the first make a check to see if there isa point of thread groove in the conventionalmanner. Then, engagement midway between positions 1 and 2 remove the work from between centers and for the second thread. The secondgroove of a replace it with the tail of the dog in another slot double thread lies midway of the flatsurface of the drive plate, as shown in figure 9-29. between the Two grooves. Thereisa point of slots are necessary for a double thread,three engagement in this case, position "b" in figure slots for a triple thread, etc. The numberof 9-28. For the same depth of cut,engage the multiples you can cut by this method depends half-nut first at one of the "a" positions, thenat upon the number of equally spaced slots in the "b" position so that alternate cuts bringboth driveplate. There are special driveor index plates thread grooves down to size together. Inthe so that you can accurately cut a widerange of event positions 1 and 2 indicate the engagement multiples by this method. place for groove of a triple thread,you must Another method of cutting multiple threads have two positions of engagement,equally is to disengage either the studor spindle gear spaced, between positions 1 and 2 in orderto from the gear train in the end of the lathe after cut the other grooves of the triple thread. you cut a thread groove. Then turn the work Cutting of multiple threads by positioning and spindle the required part ofa revolution, the compound parallel to theways should be and reengage the gears for cutting limitedto the next square and Acme external and thread. If you are to cuta double thread on a internal threads. Set the compound rest parallel lathe that has a 40-tooth gearon the spindle, cut to the ways of the lathe and cut the first thread the first thread groove in the ordinarymanner. to the finished size. Then feed the compound Then mark one of the teethon the spindle geai and tool forward parallel to the threadaxis a that meshes with the next drivengear. The mark distance equal to the pitch of the thread andcut is carried onto the drivengear, in this case the the next thread, etc. Youcan cut any desired reversing gear. Also mark the tool diametrically multiple threads in thismanner if you gear the opposite the marked spindle lathe to the lead of the multiple thread. gear tooth (the 20th tooth of the 40-tooth gear).Count the 9-24 Chapter :::--tj.!..VA.CCI',D '12^zr,:I.NE LATHE OPERATIONS

1111 rti\t-ttAISOS\O

11.

_DOG REVOLVED 130° FOR DOUBLE THREAD

28.369 Figure 9-29.Use of face plate. tooth next to the marked tooth as tooth number figure 9-30 shows thesame operation for using one. Then disengage the gears by placing the the tailstock setover method. tumbler (reversing) gears in neutralposition, turn the spindle one-half revolution or 20 teeth Note that in both methods illustratedin on the spindle gear, and reengage thegear train. figure 9-30, you set the threading The stud gear may be indexed tool square as well as the with the axis by placing the centergage on the spindle gear. However, if the lathe doesnot have straight part of the work, NOTon the tapered a1 to 1ratio between the spindle and stud section. This is important. gears, the stud gear instead of being turnedas when geared for a 1 to 1 ratio wouldbe given a proportional turn dependingupon the ratio of the gearing. The method of indexingthe stud or spindle gears is possible only whenyou can evenly divide the number of teethin !lie gear indexed by the multiple desired.Some of the newer type lathes have a sliding sectorgear that you can readily engage or disengage with the gear train by shifting a lever. Graduationson the end of the spindle show whento disengage and to reengage the sector gear for cuttingvarious multiples.

THREADS ON TAPERED WORK

The taper attachment should be usedwhen you cut a thread on tapered work. If there isno taper attachment with the lathe, cut thethread on tapered work by setting over the tailstock. The setup is the same as for turningtapers. Part A of figure 9-30 shows the methodof setting the threading tool with the thread gage 28.168 when you use the taper attachment.Part B of Figure 9-30.Cutting thread on tapered work.

9-25 2 G CHAPTER 10

TURRET LATHES ANDTURRET LATHE OPERATIONS

Horizontal and verticalturret lathes are Be aware of tools mountedon the turret generally used to produce severalidentical heads. If you are not careful they will strikeyou workpieces. Because turret lathesare designed when the turrets rotate toa new station. for production work, they havemany automatic features that are not found on engine lathes. For greatest efficiency, a turret lathe must be setup NEVER completely trust the automatic so the operator can perform the machining steps stops on a turret lathe. Be alert at all timesto with a minimum amount of control. theprogress and movement of the cutting tool(s). In this chapter we shall discussturret lathes and some of the important factors in the tooling setup. NEVER exceed the recomiaended depth of cut, cutting speeds, and feeds.

Before starting the machine, always be TURRET LATHE SAFETY alertfortools,clamping devices,or other materials adrift on the table ofa vertical turret lathe. Before learning to operate a turret lathe,you must realize the importance of observing safety precautions. As in all machine operations,you haveoneguideline:SAFETY FIRST, HORIZONTAL TURRET LATHES ACCURACY SECOND, AND SPEED LAST. The safety precautions listed in chapter8 for engine lathes apply also to turret lathes. Listed The horizontal turret lathe isa modification below are additional safety precautions thatyou of the engine lathe. The biggest differenceis that must observe to safely operate both horizontal the turret lathe has two multifaced toolholders. and vertical turret lathes. One toolholder (or turret head,as it is called) is located where the tailstock ison an engine lathe. Only authorized and qualifiedpersonne, In a typical turret lathe, the turret headhas six will operate turret lathes. faces, on each of which can be fastened various single tools or groups of cutting tools. Theother Wear goggles or a face shield whenever turret toolholder (usually square and therefore you operate a turret lathe. calledthe square turret)is mounted on a cross-slide found on an engine lathe. A typical cross-slide turret can holdone cutting tool on Be sure that long stock extending from each face. However, some typescan mount two theturretlatheisproperly guarded and or more tools on one face. Each turret rotates supported. about an upright axis. Thus, ifyou mount the

10-1 MACHINERY REPAIRMAN 3 & 2

NL ' Sr

28.159 Figure 10-1. Bar machine.

proper cutting tools on the turrets, you can do cut bar stock that must be held ina chuck or several different machining operationsin rapid fixture because of their large sizeor odd shape. sequence by merely rotating another toolor set The other main difference betweenbar and of tools into position for feeding intothe work. chucking machines is in the types of turning Moreover, you can do simultaneous,Inachining tools and holders used with the machines. operations. For instance, on a particular job,the cross-slide turrLc tool may be takingan external Sincethebar machineisdesignedto cut on the workpiece while a tail-mounted tool machine pieces that have a relatively smallcross on the turret head is performing an internal section, its hexagonal turret turning toolsmust machining operationon thepirc-such as boring, reaming, drilling,or tapping.

CLASSIFICATION OF HORIZONTAL TURRET LATHES

Figures 10-1 and 10-2 show two classesof horizontal turret lathes, the bar machine andthe ;t1 chucking machine. One main differencebetween the two is the size and shape of the workthey will machine. Bar machinesare used for making parts out of bar stock or for machining castings or forgings of a size and shape similar to bar stock. (Note that the bar machine (fig.10-1) has a stock feed attachment.) Chucking machines 28.180 are used for machining castings, forgings, and Figure 10-2.Chucking machine.

10-2 Chapter 10TURRET LATHES AND TURRETLATHE OPERATIONS be able to support the workduring cutting; saddle upon which the ram is mounted along the otherwise, the workpiece will very likely bend bedways. The stroke of the ram is relatively away from the cutting tool. short. For this reason, the ram type is not used The stock material which the chucking lathe forworkingmaterialthatrequireslong is designed to machine is usually rigid enoughto longitudinalmachiningwithhexagonal withstand heavy cutting forces withoutsupport. turret-held tools. Figure 10-3 illustrates the difference betweena bar setup and chucking setup fora hexagonal The saddle type lathe has the turret head turret. mounted directly on the saddle which, with its apron or gear box, movet back and forth on the Bar machines and chucking machinesmay be bedways. The length of the longitudinal cutyou either the ram type (fig. 10-4)or the saddle type can make with a hexagonal turret-held tool is (fig. 10.5). On the rain type, the turret headis limited only by the length of the bedways. mounted on a ram slide, whichyou can move longitudinally on a saddle that is clamped to the Hexagonal turrets found on-board ship do bedways of the machine. Theram has both hand not normally have cross feed. However,cross andpowerlongitudinalfeeds.To make feed is available on some saddle type lathes. An adjustments, you must manuallymove the example of a cross-sliding hexagonal turretis shown in figure 10-5. The small handwheel to the left of the large saddle hand feed wheel controls the manual crossfeed. Thereare levers for engaging power feed. The hexagonalturret realignswiththespindleaxiswhenthe cross-slide is returned to its starting position. Standard toolholders are used to provide cross feed for the ram type and the fixed center turret saddle type.

COMPONENTS

ABAR TURNING SETUP Many of the components of turret lathesare similar to those of engine lathes. We will discuss only the main components of the turret lathe that differ in principle of operation from the enginelathecomponents.If youclearly understand the construction and functions ofan engine lathe, you will have little difficulty in learning the construction and functions ofturret lathes.

Headstock

BCHUCKING SETUP The first important unit ofany turret lathe istheheadstock.Manylatheshavea multiple-speed motor coupled directly to the 28.101X spindle.Others have all-geared heads which Figure 10.3. Hexagonal turret turning toolsetups. provide an even wider range of spindleor chuck

10-3 MACHINERY REPAIRMAN 3 & 2

1- ilirr="3"

.

r

Figure 10-4.Ram type bar machine. 28.342

Figure 10-5.Saddle type chuckingmachine. 28.343 2G i0-4 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS speeds. TN fileitsred htads come in a variety of feed shaft, a square turret carriage apron or gear designs,each having adifferent number of box, and a hexagonal turret apron or gear box. speeds and a different method-of selecting and The number ofdifferentfeedsvaries, changing thespeeds. Some models have a depending upon thesize and model of the pre-selector that lets you set .up the different machine. On any machine, first select a range of speeds you will need for a job before you begin. feeds by shifting or changing the gears in the On these machines, speed changes are made head end gear box. Then shift the levers in the through .a minimum number of rapid changes aprons to select the desired feed. without- interferingwith the timing of the operation. Feed Trips and Stops Feed Train To save time in making a number of dupli4te parts, many horizontal turret lathes The feed train of a turret lathe (fig. 10-6) have led trips and positivestops on the transmits power from the spindle of the machipe cross-sli unit and the hexagonal turret unit to both the cross -slide and the hexagonal turret. saddle or ram, which when set, eliminate the The feed train consists of a head end gear box, a need for measuring each piece.

ing

IMED plAFT

FEEROtTOP AiroUVOI 1.

HEXAGONAL TURRET FEED SHAFT APRON (GEAR 00X)

28.185 Figure 10.8.-8eddle type turret lathe feed train.

10-5

2i MACHINERY REPAIRMAN 3 & 2

Aa_ A 6-station stop roll(fig.10-7)in the carriage and an adjustable stop rod inthe head 8 bracket allow for duplicating sizes 4 cut with a longitudinalmovementofthecross-slide 5" carriage. Stop screws in the stop roll letyou set the cutoff for any particular operation,and a STOP ROD * master adjusting screw in the end ofthe'stop rod DIAL CLIPS lets you make an overallsetup adjustment without disturbing the individualstop screws. The dial clips shown in figure 10-7are used as a reference for accurately sizinga piece by hand feed after the power crossfeedhas been knocked off by the crossfeed trips shownin figure 10-8. STOP ROLL Turret stop screws on theram type machine are mounted in a stop roll (fig. 10-9) carriedin 28.188 the outer end of the turret slide. Figure 10.7. Typical longitudinal feed The screw in stop arrangement the lowest position of the stop rollcontrols the for cross-elide. travel of the working face of theturret. The stop

9

FEED TRIPS

28.187X Figure 10-8.A typical crossfeed triparrangenient. 9 y )10'6 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

FaD -aToP

28.168X Figure 10.9. He Aagonal turret feed-stop roll on ram type machine.

roll is connected to the turret so that when a particular face of the turret is positioned for 28.169X work, its mating stop screw is automatically Figure 10-10.Hexagonal turret feed stops on saddle aught into correct position. type machine. To set the hexagonal turret stops on ram type machines: groove on the stoproll,the locking screw nearestthemasterstopwilllineup 1.Run a cut from the turret to get the automatically with the next locking groove. desired dimensions and length. 3.Screw down the first lock screw, at the 2.Stop the spindle, engage the feed lever, same time pressing the stop dog toward the head and clamp the turret slide. end of the machine. 3.Turn the stop screw in until the feed 4.Screw down the second lock screw and knocks off: then continue turning the screw in then adjust the stop screw until itmoves the until it hits the dead stop. master stop back to a point where the feed lever knocks off. Then tighten the center screw to On saddle type machines, the stop roll for bind the stop in position. the hexagonal turret is located under the saddle and between the ways (fig. 10-10). The stop roll Threading Mechanisms does not move endwise; it automatically rotates as the turret revolves. To set the stops: ,Thereareseveraldifferent methods for producing screw threads on a turret lathe. The 1.Mov, the dogs back to the outer end most common method is to use taps and dies of the roll, where they will be in a convenient attached to the hexagon turret. The design and position. Select a turret face and allow the proper use of these tools will be covered later in master stop to engage the loosened stop dog. this chapter. A thread chasing attachment (fig. After you take the trial cut, the stop dog will 10-11) allows the machining of screw threads on slide ahead of the master stop. a surface up to about 7 inches long. There are two major parts to this attachment. The leader is 2.After you have take., the proper length a hollow cylindrical shaft that clamps over the of cut, stop the spindle, engage the longitudii. tl feed rod of the turret lathe. You can position it feed lever, and clamp the saddle. Then, adjust anywhere along the feed rod for alignment with the stop dog to the nearest locking position with the surface 'Nuking threads. The follower is a the screw nearest the master stop. When the end half-nut type arrangement, similar to an engine of the dog is flush with the edge of a locking lathe. Itis bolted to the carriage and engaged

10-7

2'ki MACHINERY REPAIRMAN 3 & 2

28.344 Figure 10-11.Thread chasingattachments.

overthe threadedpartoftheleader. systems and have peepholesat strategic points Disengagement is either manualor automatic, in the system so thatyou can tell at a glance depending on the model. Thisattachment can whether oil is being circulated to normally be installed on existing the areas where equipment. An it is required. When cleaninga lathe, use a cloth attachment that requires factory installationis orbrushto remove the lead screw threading attachment chips. DO NOT use (fig. 10-5). compressed air to cleana lathe. Compressed air This attachment gives the turret lathethe same islikelyto blow foreign matter into threading capability as the an engine lathe. A lead precision fitted parts, causing extensivedamage. screw extends the working length of the latheto allow forthreadinglongworkpieces.A TOOLING HORIZONTAL quickchange gear boxon the headstock end of TURRET LATHES the lathe provides fora wide and rapid selection of a number of threadsper inch, As previously mentioned, horizontalturret lathes fallinto two general classes, thebar machines and TURRET LATHE OPERATIONS the chucking machines. The principal differences between thetwo classes are in the size and shape of theworkpieces they Aside from additional controllevers and handle, the type of workholding additional device, and the automaticfeatures,theprincipal type of turning tools employed in the differences between operatingan engine lathe hexagonal turret.Inthefollowingparagraphswhich and a turret lathe lie in the methodsof tooling describe and in the methods cif setting worldioldingdevices,grinding and up the work. In settingcutters,andvariousmachining this section we will discussturret lathe tooling procedures, we make no particular principles and methods of doing typical distinction as Jobs in to the class of machine involved,because it will horizontal arid vertical turret lathes. usually be obvious; where it is Propermaintenanceis not obvious, the importantfor information applies to horizontalturret lathes in efficient productionon a turret lathe. Specific general. The preceding information maintenance procedures for also applies a specific turret to the two types of machines, theram type and lathe are given in the manufacturer'stechnical the saddle type. Examplesof some of the manual. Before startinga lathe, ensure that all commonly used tools for bearings are lubricated and that the a chucking machine machine is are shown in figure 10-12 and tools fora bar clean. Turret lathes have pressurizedlubrication machine in figure 10-13.

10-8 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

ADJUSTABLE CUTTER HOLDER

SINGLE TURNING \HEAD

RELEASING TAP HOLDER

SADDLE TYPE

FLANGED TOOL HOLDER (LONG)

REVERSIBLE MULTIPLE ADJUSTABLE CUTTER HOLDER TURNING HEAD FLOATING REAMER HOLDER

28.345 Figure 1012. Turret lathe chucking tool..

10-9 2;; MACHINERY REPAIRMAN 3& 2

CENTER DRILLING TOOL

FLANGED TOOL HOLDER ( SHORT)

POINTING TOOL ADJUSTABLE TOOL

COMBINATION BAR STOP AND STARTING DRILL

COMBINATION TURNER AND END FORMER

28.348 Figure 1013.Turrst laths bytools.

10-10 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS As a good turret lathe operator, your aim should be to tool and operate the machine so as to turn out a job as rapidly and as accurately as possible. Always keep in mind the following BLOCKED OFF factors: FACE INTERNAL Keep the total time for a job at a FACE i FORM minimum bybalancingsetuptime,work handlingtime,machine-handlingtime,and actual cutting time. CUT OFF

Reduce setup time by using universal ROUGH TURN equipment and by arranging the heavier flanged 411 type tools in a logical order. A Select proper standard equipment. Use special equipment only when it is justified by the quantity of work to be produced.

Reduce machine handling time by using the right size machine and by taking as many multiple cuts as possible. Reduce cutting time by the following methods: (1) Take two or more cuts at the same time from one tool station, (2) take cuts from B the hexagonal turret and the cross-slide at the same time, and (3) increase feeds by making the 26.171X setup as rigidas possible by reducing tool 10.14.. lows turret tool positions. overhang and using rigid toolholders.

Never block off stations on the square hold t',, succeeding raw workpiece without turret. (See fig. 10-14). your ing to stop to take measurements or

rn a I1/4 1djustments.(Remember:SAFETY Keep the distance that each tool projects FM ST.'. CCURACY SECON), AND SPEED from the hex turret as equal as possible. This 1,A Si ..ne semiautomatic collets, arbors, and will minimize the length of travel required to c14.1.:.described in the following sections are retract each tool for to the nt xt one. .ado this.

COLLETS.The sprir.6-type pusliout collet Holding the Work ilJtown in tigure 10-15 ig the rrius4. widely used. It is made in different sizes bar stock Ltp ti, 2 1/2 inches in diameter. principle upon Horizoul 11turret lathes are generally used which it works is P.s follows: When you engage forturningoutmachinepartsrapidlyin the bar feed lever. Cie machine to start the bar quantity. The workholding devices mu: t. be such feed head (fig. 1(.)-):+ik) to advance the stock, it that you spendlittletimein placing stock simultaneously !omens the grip of the collet. material in the machine. Moreover, to produce When the end of the bar stock butts againsta duplicatepartsofuniformcorresponding stockstopmounte,:ion oneface of the dimenrns, once you have set the tools, the hexagonal turret, the plunger (Part A in fig. workholding de -ce mist be able to position and 10-15B) for-es the partially split tapered end of

10-11 2 MACHINERY REPAIRMAN 3 & 2

BAR FEED HEAD

A BAR FEED LEVER

PLUNGER HE /ID FINGER HOLDER fulNDLE HOOD A :. C COLLET

STOCK

SPRING ryp: P 1S111,-JUT :OLLET

28.172X Figure 10-18.Bar feed device andspring type pushout collet mechanism.

collet 1) into the taper of the hood C, cat,sing The expanding plug-type arbor(fig. 10-17) the collet to grip the stock firmly.Your on,. enters the workpiece more accurately simple movement automatically and is setti,t:sto, k usually used for secondor finishing operations. material into position for machining. In this type, when the taperheadud Thereareseveral screw is variationst,fthe pulled to the left by the actionof the draw bar spring-type collet, but they all depend.00n the C, it expands the outer end of the plunger head principle for gripping partially split and leasing plug D enoughtogripthe workpiece A the stock, differing only in thedirection of taper on the collet. internally and at thesame time forces the workpiece tightly against thestop plate B. This A R BORS. For mountingsmall,rough castings or for mounting workpicets of second operations, youwilloftenuse quick-acting arbors.

l'figure 10-16 is an expandingbushi. irtype arbor. In this type arLor, as draw bar C is pulled 111141; back, the split bushing D climbsthe taper of the J arbor body, expanding to grip Ar& the workpiece A I OMVA"'11W tightly along its entire lengthand at the same 6,4...16...,.tee time forcing the workpiece againststop plate B. This type of arbor is suitable forroughing work or first operations, where a firm grip forheavy feeds is more important than 28.173X accuracy. Figure 10-18.Expanding bushingtypearbor.

10.12 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

28.174X Figure 10-17.Expanding plug-type arbor.

type or arbor is used for holding workpieces that have been bored or reamed to size internally, rough machined to size externally, and need only a light finishing cut as a final operation.

CHUCKS.These workholding devices fall ,h4, into three classes: (1) univeral chucks of the geared scroll, geared screw, or box type, where allthree jaws move atthe same time; (2) independent chucks, where each of the jaws is operated independently; and (3) combination 28.175X chucks,where each jaw may be operated Figure 10.18. A 4-jaw combination chuck. independently, but where all jaws can be moved' as a group. the work in the first chuckings. You can then The 2-jaw chuck is used mostly for holding use the same chuck for second operations by small work or irregular shape. The jaw screw using the geared scroll to operate the jaws when operates both jaws at the same time. Use an gripping on a finished diameter. Soft metal (such adapter to attach chuck jaws of various shapes as copper shims) is often used with chuck jaws to the master jaws. for chucking second operation work to prevent marring the finish of the workpiece. The 3-jaw geared scroll chuck is used more thananyothertype.Withstandard jaw Some machines have a power chuck wrench equipment, it holds work of regular shape. It can that you use with 3-jaw chucks. This attachment be adapted to hold irregularly shaped work. lets you open and close the chuck by a lever located on the headstock. There is a control Figure 10-18 shows a 4-jaw combination knob for adjusting the pressure of the chuck to chuckwhichhastwo-piecemaster-jaw allowfor gripping different workpieces. An construction and an independent jaw screw example of such an attachment can be seen on between sections. The bottom or master part of the turret lathe in figure 10-5. the jaw is moved by the scroll, and the top part is moved by the independent jaw screw. Chucks Grinding and Setting of this type are used mostly to hold irregularly Turret Lathe Tools shaped work or when a jaw needs to be offset from a true circle. On the combination chuck, The angles to which a turret lathe tool is you use the independent movable jaws to true ground and the position at which it is setcan

10.13 MACHINERY REPAIRMAN 3 & 2

change the angle that the cutting edgeof the to remove large quantities of metal tool forms with the work. The angles rapidly. Bar ground turner cutters, or box toolsas they are often and thepositionsetaffectthe chip flow, called, are ground in a different pressure exerted on the tool, and the amount of manner. feed and depth of cutthat can be used. Bar turner cutters are usually Consequently, accurate tool angles held in a and proper semivertical position. That is, thecutting edge or tool position are essential to productionwhen tool point, which is located you use a turret lathe. near the center of the cutter end, points slightly towardthe cut and toward the center of thework. In this GRINDING.Some importantpointsto position, the pressure of thecut is downward keep in mind when grinding turretlathe tools through the shank of the cutter. are: liar turner cutters are groundto form the tool point on the end of the Do NOT esthnate the tool angles cutter, near the you centerline, somewhat likea chisel point. The bar should use, nor the tool angleyou should grind. turner cutter in figure 10-19 is in the Consult a tool angle chart (see chapter position it 6 of this would be held in the holder.Normally, in manual) to determine the correctangles. To check the angle when sharpening, you grind only angle surfacesA (the you grind a cutter, use the top). You hone angle surfacesB and C to cutter grinding gage or the barturner cutter remove burrs which result from grinding surface grinding gage, as appropriate.These gages are A. After repeated sharpenings, part of your lathe equipment. angle surfaces B and C will become too small andyou must then grind them. The tool anglesfor a bar turner Some cutters are ground wet; othersare cutter are the same as those ground dry. High-speed steel on a cross-slide cutters are usually mounted cutter, but theyappear to be vastly ground wet, while Stellite andcarbide cutters are usually ground dry. When grinding wet, keep thecutterwell-flooded toprevent heating; nothing will ruina cutter quicker than a wet C (UNDERSIDE) grinding that is partially dry. On theother hand, if the cutter should be ground dry,do not dip the tip in coolant. Sudden coolingwill cause surfacecracks,whichoncestartedwill eventually cause the cutter tip to fail. When a carbide-tipped cutter requires sharpening, use the grinder specifiedin your shop for that purpose. Grindingwheels suitable for high-speed steel will ruin carbidecutters.

When you are grindinga carbide-tipped cutter, manipulate it so thatpressure of the grinding will be toward the seat ofthe carbide tip rather than away from it.

The tool angles of single cutters andmultiple turning head cutters' for thesquare turret and hexagonal turret, respectively,are quite similar to those employed in engine lathe toolbits or turning tools. But the cutters themselvesare usually much larger than those usedon an engine lathe because the turret lathe is designed 28.176X Figure 10.19. Bar turner cutter toolpoint.

10-14 2I Chapter 10TURRET LATHES AND TURRET LATHE(.RATIONS different because of the difference in tool point location.

CONTROLLING CHIPS.Chipscanbe controlled in one of two ways: (1) get the right combination of back and side rake angles in combination with speeds and feeds or (2) grind on the back rake face of the cutter a chip breaker groove which will curl and break chips into short lengths. Method (1) is usually the best way. By changing the angle slightly, it is possible to throw chips in one direction or the other. If you use method (2), start the chip breaker groove just behind the cutting edge; be careful not to carry it through the point of the cutter. A chip breaker groove through the point of the cutter will tend to break down the cutting point, produce a poor quality of finish, andmay 28.178X produce a double chip (fig. 10-20). Figure 10-21.Keep cutters on center. SETTING SINGLE AND MULTIPLE TURNING CUTTERS.To retain all of its small cutter above center. A cutter set in the position front clearance angle, a turret lathe cutter must shown has only a fraction of the amount of be set in its holder so that its active cutting edge front clearance needed under its cutting lip and is on the same plane as the centerline of the has an unnecessarily large back rake angle. On work, and not above center as tool bits are often the other hand, if a cutter is set below center for set in engine lathe operation. Part A of figure cutting small diameter work, the work isvery 10-21 shows a cutter in correct position. This likely to climb the cutter, or at leastcause cutter-workpiecerelationisvery important violent chatter. when the workpiece diameter is small. Observe Figure 10-22 shows how to seta square in part B of figure 10-21 the effect of raising the turret and a "reach over" or rear-tool station

SPINDLE CENTER

MARI TURRET ROAR TOOLPOST

MEASURE PROM TOP OP IUIIIT, USING Ull A {CALI TO MEASURE TM CORRECT CUTTER GRINDING ANO SETTING GA61 POSITION OP TNE CUTTER PROM TOP OP 'rHN CAOiPILIDIl

28.177 28.179 Figure 10.20. Double chip caused by grindinga chip Figure 10-22.Sottli.g square turret and "reach over" breaker groove too dose to cutting edge. toolpos% cutters on center. 10-15 MACHINERY REPAIRMAN 3 &2 cutter on center. Notice that the cutter in the Each time you regrinda cutter-(other than a "reach over" toolpost is inverted;the reason for carbide-tipped type), the height thisis that the work surface rollsup from of the tool underneath. point and the length of thecutter itself are reduced; therefore, after eachgrinding you must In sqt&re turrets,you can raise or lower the reposition the cutter in its holderto place the cutter to cOrect position byeither shims or tool point on center. Ifyou use a shim type rockers, dependingupon the type of base plate holder, raise the cutterto center by adding a (fig. 10.23). shim of appropriate thickness(fig.10-238). When using a rocker Another factor to consider in arrangement, you need an setting a cutter entirelydifferentapproach; is the amount of its overhangfrom the holder. elevatingthe Too much overhang will reground tool point to center byadjusting the cause the cutter to rocker will cause the clearanceand rake angle to chatter, and insufficientoverhang will cause the change. The best way to holding device to foul the work. maintain the proper When possible, angles and yet keep the toolpoint on center, you should, keep the amount of overhangequal whenusingthe rocker arrangement, to or slightly less than twice thethickness of the isto cutter shank. decrease the top (back and side)rake angles and increase the front clearanceangle slightly at each grinding in anticipation of thechange in cutter position caused by removalof metal from the tool point. Figure 10-23Ashows how this is done.

The dimensions of carbide-tippedcutters are relatively unaffected by grinding;therefore, the cutters seldom require alterationin holder setup after they have been reground.The shim type holder presents a stable horizontalbase for the cuttershankand isbestforholding carbide-tipped cutters. Thecutters can be taken out, reground, and placed backin and on center without undue manipulation. The overhead turningcutters, which are mounted on the hexagonalturret, must also be on center in relation to the work. Theprinciple involved in setting these cuttersis not different fromthatinvolvedinsettingthesquare turretmounted cutters, thoughat first it may appeartobe different.In order toassure yourself that this isso, look at figure 10-21 !Ad turn the book so that thecutters point two's,. rd the work from above ratherthan from the side. Figure 10-24 shows howto set an overhead turning cutter on center byusing a scale for reference in bringing the shankand tool point of the cutter into radial linewith the center of the turning head, which isan alignment with the center of the spindle.

28.180 SETTING BAR TURNER Figure 10.24.A. Use of rockers. CUTTERS.Bar B. Use shims. turners are held on the hexagonalturret and

10-16 I 4,) Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

0 0 CUTTS

28.182X 0 Figure 10.25.Rolls. A. Behind cutter. B. Ahead of SCALI cutter. SOLI CENTER illustrated in figure 10-26A. Another type, the single-bar turner (fig.10-26B), has adjustable roller arms; the cutter is fixed, and the rollers can be moved ahead of or behind the cuter. 28.181X Figure 10-24.Setting overhead turning cutter on center. Use the following steps insetting up a SINGLE BAR TURNER: combine in one unit a cutter holder and backrest 1.Extend the bar stock about 1 1/2 to 2 that travels with the cutter and supports the inches from the collet. Then with a cutter in the workpiece. The backrest holds the work against square turret on the cross-slide, turn the bar to the cutter so that deep cuts can be taken at 0.001 inch under the size desired for a length of heavy feeds. 1/2 to 1 inch.

Backrests on bar turners usually have rollers 2.With the roller jaw swung out of position toeliminatewear and to make high-speed (fig.10-27A) and with the cutter set above operationpossible.Barturnersthathave center, adjust the cutter slide of the turner V-backrests are used for turning brass where against the turned portion of the bar stock and there is no problem of wear and where small rub a shine mark on the turri'ed portion, as chips might get under rollers andmar the indicated in fig. 10-278. workpiece.

The rollers on a ROLLER-TYPE TURNER may be either ahead of or behind the cutter. If they are behind the cutter,. they burnish the workpiece. This burnishing is often an important factor; it may eliminate the need for polishing or grinding operations. When a diameter is turned so that it is concentric with a finished diameter, the rollers are run ahead of the cutter on the previouslyfinishedsurface.Figure10-25 illustrates rollers behind and ahead of a cutter. The rollers on a UNIVERSAL TURNER are set ahead of or behind the cutter by adjusting 28.183X the movable cutter with the rolls remaining in Figure 1028.A. Universal bar turner. B. Single bar fixedposition. The universalbar turneris turner.

10-172 MACHINERY REPAIRMAN 3 &2

BAR TURNING.The followingpointers will be helpful in bar turning:

To prevent making markson the work as you bring back the turret, alwaysuse the wildrawal lever before thereturn stroke of the turret. A When rollersare set to follow the cutter, itis usually true that theheavier the cut the Figure 1027.Rubbinga shine mark to establish center. better the finish. The heavier thecut the greater A. Roll jaws out of position. B. is the pressure against the rollers,and the greater Shine mark on is the burnishing action. turned portion. .

If you are using lightcuts, special rollers 3.Set the cutter at the centerof the shine with a steep taper willsometimes produce a mark, clamp the cutter tightlyin its slide, turn better finish. the spindle to move the shinemark away from the cutter point, and adjust theslide until the Regardless of the depth ofcut, there are three factors that cutter is 0.0015 inch from the turneddiameter. you must watch to get a high You now have the cutterset, and the rollers grade finish: (1) thefaces of the two rollers should be positioned endwiseand adjusted to must be in line, (2) the leadingcorners of the size. rollers must be perfectlyround and exactly equal, and (3) end play inthe rollers should Lot 4.Align the rollers with theback of the exceed 0.003 inch. point radius of thecutter, as shown in figure 10-28. Adjust the rollerswith the clamping Selecting Speeds and Feeds screws, and then clamp tightly. Therollers are in proper adjustment when LIGHT PRESSURE The general rules for feeds andspeeds in WILL STOP THEM FROMTURNING as the bar chapter 8 of this manual stock is revolved. for engine lathe operation apply also to turret lathes.However, 5.Push the cutter to cuttingposition with since the cutters and themachine itself are the withdrawal levet and takea trial cut. If you designed for prodUctionwork, you cr I take have a proper setup, the sizewill be accurate to heavier roughing cuts thatyou ordinarily would ±0.001 inch. with an engine lathe. Bear in mind that the spindlespeed of the turret lathe must be governedby the surface speed at the point of work ofVac cutter farthest FACE OF ROLL IN LINE WITH BACK from the rotating axis. That is,if you are going or RADIUS OF to use two cutters CUT TER on a workpiece with one cutter to turn a small diameter andthe other to cut a much larger diameter,the headstock rpm you select must be basedon the surface speed tat the large diameter. Disregardthe fact that the cutter at the small diameter willnot be cutting at anywhere near its permissiblerate. Using Coolants

28,185 Using coolants makes itpossible to run the Figure 10.28.Roll aligned withcutter. lathe at higher speeds, takeheavier cuts, and use 10-18 2, Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS cutters for longer periods without regrinding, MONEL/NICKEL ALLOYSSoluble oil 1 thus getting maximum service from the lathe. to 20 ratio, or a sulfur-based oil Coolants flush away chips, protect machined parts against corrosion, and help give a better The selection of the best coolant or cutting finish to the work. A coolant also helps in fluid depends on the cutting tool materials; the greater accuracy by keeping the work from toughness of the metal being machined ands the overheating and becoming distorted.Figure type of operation being performed. Simpk 10-29 shows theincorrect and the correct turning may require a coolant that keeps the methods of applying cutting oil or coolant. temperature down and flushes chips away. A mixture of soluble oil that has a low oil ratio Some coolants and the materials with which will do this very efficiently. An operation such they are used are listed below: as threading or heavy turning requires something that riot only cools but also lubricates. A heavier, CAST IRONSoluble oil1 to 30 ratio, or soluble oil mixture or mineral lard oil satisfies mineral lard oil, or dry these requirements.

ALLOY STEELSoluble oil 1 to 10 ratio, BORING or miner:) lard oil Two general types of boring cuttL:s are LOW/MEDIUM CARBON STEELSoluble usedtool bits held in boring bars and solid oil I to 20 ratio, or mineral lard oil forged boring- cutters. Tool bits held in boring bars are most common. This combination allows BRASSES AND BRONZESSoluble oil 1 to great flexibility in sizes and types of work that 20 ratio, or mineral lard oil can be done. Solid forged cutters, however, are used to bore holes too small to be cut with a boring bar and inserted cutter. STAINLESS STEELSoluble oil 1 to5 ratio, or mineral lard oil The cutter in a STUD BORING BAR is held either at right angles to the bar or extended ALUMINUM Soluble oil 1 to 25 ratio,or beyond the end of the bar at an angle. This dry extension of the cutter makes it possible to bore up to shoulders and in blind holes. The angular cutting bar has the added advantage of an adjusting screw behind the cutter. When the stub boring bar or forged boring bar is used, the overhang should be as short as the hole and the setup will permit. You should always select the largest possible size of boring bar to give the cutter as rigid a mounting as possible. You should never extend the boring cutter farther than is actually necessary.' You can use sleeves to increase the rigidity of small stub boring bars and to reduce the effect of overhang. The increased rigidity helps to make the work more accurate and allows for heavier feeds. 28.186 Figure 1029.Correctandincorrectmethods of The HEXAGON TURRET is ordinarily used applying coolant. in making boring cuts, although, if necessary,

10-19 MACHINERY REPAIRMAN 3 &2

boring toolsan field on the cross-slide. The advantages oftak;ng a boring cut fromthe hexagon turret are:

I.You can Lkc turningor facing cuts with the cross-slide at thesame time you take a boring cut with the turret. 2.You can combine boring cutters with CENTERLINE turning cutters in multipleor single turning heads. SCALE 3.You can mount varioussize cutters 0 eliminating the need for adjustingthe cutter as the bore size increases. CUTTER 4. When aquantityoflikepiecesis required, you can increase boring feed by using a VER CAL boring bar with two cutters.It is good practice when using double cuttersto rough bore with a piloted boring bar to obtainrigidity for heavy feeds and then finish thehole with a stub boring bar held in a slide tool. 28.187X Figure 10-30.Setting a boringcutter on center. Piloted boring bars requirea machine with a long stroke- -the saddle typeso that the turret Forming can be moved far enough to pull thepiloted bar from the pilot bushing andthe work before One of the fastest methodsof producing a indexing the turret. Usually,when the pilot finished diameter bushing is mounted in the or shape is by forming. In chuck close to the planning a setup, you shouldstudy the work to work, the effective travelof the turret must be determine if forming tools about 2 1/2 times Elie lengthof the workpiece. can be used. It is possible, omany jobs, tocombine two or more cuts into one operation byusing a specially Grinding Bo rin,tut ten designed forming cutter.'Forming cuttersare also used to produce irregularand curved shapes that are difficult to produce Boring cuttersare ground inthe same in any other way. There are three types of formingcutters you will manner as other types of cutters, withone major useforged, dovetail, and circular. difference.The clearanceanglesof boring cutters must be greater to prevent FORGED FORMINGCUTTERSare rubbing since ordinarily mounted directlyin the square turret a boring tool cuts on the inside instead ofon the outside of the work. or toolpo.st and are the leastexpensive to make. However, the clearance They have, however, the angle must not be too great,or the cutting edge shortest productive life. DOVETAIL FORMINGCUTTERS are held break down because ofinsufficient support. The exact amount of front in toolholders mountedon the cross-slide. Their clearance angle will shape or contour is machinedand ground the depend on the size of the holeyou are boring. full length of the face, The smallerthehole,the more clearance and the cutters are set in required. Thereare no set the holder at an angleto provide front clearance. rulesfor exact When the cutter wears,you need to regrind only clearance angles; knowledge ofwhat will be the the top. Dovetail cutters best angle comes withexperience in operating cost more than forged the lathe. cutters, but they havea longer productive life, Figure 10-30 shows how are more easily set up, maintain theirform after to center a vertical grinding, are more rigid,and can be operated slide tool-held boring cutter. under heavier feeds.

10-20 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

CIRCULAR FORMING CUTTERS have an The solid adjustable taps and dies should be even longer life than dovetail cutters. The shape used in place of collapsing taps and self-opening of circular cuttersis ground on the entire die heads only when speed is low and when time circumference and, as the cutting edge wears required for backing out is not important. away, you regrind only the top. After grinding, Collapsing taps(fig.10-32) are used for move the cutter to a new cutting position by internal threading. They are timesavers because rotating the cutter aboutitsaxis. (See fig. you do not have to reverse the spindle to 10.31.) withdraw the tap. The pull-off trip type, which NEVER regrind circular forming cutters on a is collapsed by simply stopping the feed, is the bench grinder. Regrind them on a toolroom most frequently used. grinder where they can be rigidly supported and ground to maintain the original relief angles. Various types of self-opening die heads are used. One type is shown in figure 10-33. Some Threading have flanged backs for bolting directly to the turret face; others have shanks which fit into a For turret lathe operationi, dies and taps holder. The die heads. are fitted with several provide a means of cutting threads easily and different types of chasers. The tangential and quickly and, usually, in only one pass over the circular type chasers can be ground repeatedly work. Dies and taps for turret lathes are divided without destroying the thread shape. They are a into three general types: Solid, solid adjustable, bit more difficult to set, but they are better and collapsing or self-opening. adapted thanflatchasers for long runs of identical threads. Solid taps and dies are usually held in a pos- Die heads come witn either a longitudinal itive drive holder that has an automatic release float or a 'rigid mounting. They may be the (fig. 10.12). A longitudinal floating action (not pull-off, outside, or inside trip type. The floating to be confused with a floating die holder) allows type should be used for heavy duty the tap or die to follow the natural lead of the turret lathe work, for fine pitch threading, and thread, which prevents having to depend on a for finishing rough-cut threads. delicate "feel" to produce results. Solid dies are used only when the thread to be cut is too coarse for ti-.e self-opening die head or a solid adjustable die head, or when the tool interferes with the setup.

OLDER IS USED ON FRONT AND REAR OF CROSS-SLIDE BY TURNING ECCENTRIC BUSHING 180'

28.188X 28.347 Figure 10.31. Circular forming cutter diagram. Figure 10-32.Universal collapsing tap.

10-21 MACHINERY REPAIRMAN 3 &2

28.190X Figure 10-35.Angular feed-in withadjustable threading toolholder.

with a single-point tool. In suchmachines, there 28.348 are two methods of feeding the threading Figure 10-33.Pull-off trip self-opening tool dig head. into the work. The first methodis to get An angular feed to the cutter bymeans of the compound cross-slide (fig.10-34) or by using On some types of workit is necessary to the angular threading toolholder take both roughing and finishing (fig. 10-35). By cuts. They are the first method, the cutteris fed into the work normally taken when threadinga tough material at an angle until the final polishingpasses are or when a smooth finish is required.Some types of die heads have both roughing made. For the final polishingpasses, the cutter is and finishing fed straight in bymeans of the cross-slide. The attachments. If such die headsare not available, second method is to feedthe cutter straight into roughing and finishing cutscan be taken with the work for each separate dies or taps setup on different turret pass, as indicated in figure stations. 10-36. With this latter methodyou apply by hand a slight drag to thecarriage or saddle As mentioned earlier in thischapter, some during the roughing cut and horizontal turret lathescan cut or chase threads remove the drag during the final polishingpasses. It takes more skill to use the second method,but it produces better threads.

'Ii 28.189X Figure 1^-34.Compound cross-slideangular feed-in for thread cutting. 28.191X Figure 10-a. light-it. feeding method of threading.

2 ;1:5 10-22 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

Taper Turning

Tapers may be produced on a turret lathe with (1) forming cutters, (2) roller rest taper ..:rners, or (3) taper attachments.

Forming cuttersr the forged, circular, or straight dovetail type., ma, be used to produce tapers when the workpiece is rigid enough or can be supported in such a way that it will withstand the heavy forming cut. If work cannot be I. GUIDEPLATE 5. SETSCREW formed, other methods (described later) must be 2. BASE PLATE 6. BINDER SCREW used. 3. CARRIAGE PLATE 7. STOP COLLAR Work should be shaped with forming cutters 4. EXTENSION ROD 8. LATCH only when the following conditions are met: 28.192X 1.The work is either self-supporting or is Figure 10-37.Detail of crossslide taper attachment for supported by a center rest. so that chatter is saddln type machine. prevented.

2.The finish must meet requirements. the setscrew (5), and loosen the binder screw (6). \3. The taper angle must be accurate. c.You can use the stop collar (7) and the is best to use the roller rest taper turner latch (8) for locating the cross-slide unit on the for long taper bar jobs. You can quickly set this bed of the machine. To use the stop collar and tool for size by means of the graduated dial and the latch, move the cross-slide unit to the left then control the angle of taper accurately by the until the stop collar comes in contact with the taper guide bar. latch. This locates the entire unit. Taper attachments are provided for the cross-slide of most turret lathes of both ram and Taper attachments are fitted with a backlash saddle type. These attachments can be quickly eliminator nut (fig. 10-37) for the slide screws. set to produce either internal or external tapers. Tighteningthisnutagainstthe feed screw They do not interfere with normal operation removes all play between the feed screw and the when lot in use. Most taper attachments are nut. movable and can be quickly located at any To duplicate and maintain accurate sizes position on the bed. when using a taper attachment with other tools Taper aItachments all have a pivoting guide in a setup, remember these three things; (1) you plate which can be adjusted to any taper angle. must accurately locate the attachment in the Figure 10-37showsasaddle-typetaper same position in relation to the cross-slide each attachment in detail. timeitisused,(2) you must locate the Figure 10-37 is broken down for study as cross-slide in exactly the same spot on the bed follows: when you clamp the extension rod with the setscrew, tighten the binder screw, and loosen a.The guide plate (1) pivots on the bate the extension rod, and (3) be sure the cross-slide plate (2), which sli!.zs in carriage plate (3). is in exactly the same position as in (1) above.

b. When you plan to use the attachment, You can produce either internal or external clamp the extension rod (4) to the machine with threadswiththetaperattachmentin

10-23 2'Yj MACHINERY REPAIRMAN 3 & 2

EXTERNAL TAPER THREAD INTERNAL TAPER THREAD SQUARE TURRET ADJ. THD*0 TOO LHOLDE H

TAPER ATTACHMENT HEX.TUp T ADJ. THREADINQ TOOL' HOLDER

LEADER AND FOLLOWER OR LEAD SCREW It4ItlAt AMAINVANWIIVAil TAPER ATTACHMENT

LEAD SCREW OR ADER AND FOLLOWER

28.193X Figure 10-38.ExterAlon,. &Arnel taper threading.

5.

55 559

.13J

v CUT -OFF STOCK STOP IV . THREADO

... - h

L.'. ...,11 w r iII FORMO

lEcri III II v ROUND TURNOC.).

126.10X Figure 10-39.A. A shoulder stud. B.Tooling setup for sht.older stud.

10-24 Chapter 10TURRET LATHES AND TURRET LATHE OPE RATIONS conjunction with a lead screw thread chasing showsthesetupformediumquantity attachment. (See fig. 10-38). Notice, 11 wever, production. that taper cutting with hexagonal turret held cutters is possible only on lathes that have a buth small and medium lot production, cross-sliding hexagonal turret. the turning of diameter (6) and the forming of diameter (7) can be combined with the turning of diameter (3). In addition, the facing and HORIZONTAL TURRET chamfering of the end (2) can be combined with LATHE TYPE WORK the turning of diameter (7). For small lot production (part A of fig. The following information is included to 10-40) the taper isgenerally formed with a give you some examples of turret lathe type standard wide cutter, ground to the proper work. Regardless of the job, your aim asc good angle, and then the cutis matched. These turret lathe operator is to tool up the machine matched cuts will not be very accurate, but as and operate it so that the job can be turned out the taper will be ground in a later 0;Teiation, the as rapidly and as accurately as possible. The job will be satisfactory if sufficient stock is left following examples show you how. for grinding. If a forming tool wide enolgh to ,-ut the taper in one cut is available, it should be used. A Shoulder Stud Job For ,nedium lot production (part C of fig. 10-40) the cross-slide taper attachment may be A shoulder stud, shown in' part A of figure set up and used for single point turning of the 10-39,isatypicalbar job (universalbar taper. The same amount of time will probably equipment is used) for a small ram type turret be required to turn the taper (part C. fig. 10-40) lathe that has a screw feed cross-slide. The lsto form the taper (part A,fig.10-40). tooling setup for the shoulder stud is shown in How. 'ter, the turned taper will be more accurate part B of figure 10-39. The diameter (5), which and requite less stock for grinding. In addition, must be held to a clearance of 0.001-inch the grinding opeAtion will take less time. tolerance, is formed with a cutter on the front Figure 10-41 shows a simple setup for the of the cross-slide. Diameters (2) and (3)are second operation of the tar :r stud. Thesetup is turned from the hexagon turret with cutter., thetame for producing ci Sher a small or a held in the multiple cutter turner. After this mediu i he quantity. operation,theradiuscatheend of the workpiece is machined in a combination end facer and turner, then the thread is cut, and the VEFTICAL TURRET LATHES piece is cut off. #1 vertical turret lathe werks mi. '.1!-.e an engir,lathe turned up on end. 1'ou can perform A Tapered Stud Job practically all of the typical lathe operations in a vertical turret lathe, including turning, facing, boling, machining tapers, and cutting internal A tapered stud, shown in part B of figure and external thr, aus. 10-40, does not offer much opportunity for The characteristic features of th:, machine taking multiple cuts. However, cuts from the are: (1) a r orizontal table :siceplate that holds cross-slide can be combined with cuts taken by the work and rotates about a vertical axis; (2)a the hexagon turret. The tooling setup for the side head that can be f'either horizo-itally or taper stud, shown in part A of figure 10-40, is vertically; and (3) a turret slit mounted on a used forsmalllotproduction. The almost crossrail that can it ed nonrotating tools either identical tooling layout in part C of figure 10-40 vertically or horizontally.

10-25 261 MACHINERY REPAIRMAN 3 &2

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126.11X Figure 1040.A. Toolingsetup for taper studsmall lot production. B. A taper stud. C. Toolingsetup for taper studmedium lot production.

1 0-26 Chapter 10TURRET LATHES AND TURRET LATHE OPERATIONS

126.12X Figure 10-41.Tooling setup for second chucking on taper stud.

Figures 10-42 and 10-43 show vertical turret plate W:ows the turret slide to be swungup to lathes similar to those generally found in repair 45° to the right or left of the vertical, depending ships and tenders. The main advantage of the on the machine model. The saddle is carried on vertical turret lathe over the engine lathe is that and can traverse, the main rails (5). The main heavy or awkward parts are easier to setup on railsare gibbed and geared to the upright thevertical turret lathe and, generally,he bedways(6)forverticalmovement.This verticalturret lathe will handle much larger arrangement allows main turret tools to be fed workpieces than the engine lathe. The size of the either vertically or horizontally, as compared to verticalturretlatheisdesignated bythe the single direction movement of the hexagonal diameter of the table. For instance,a 30-inch turre : on the horizontal turret lathe. Also, tapers lathe has a table 30 inches in diameter. The can bf. 7.ut by setting the turret slide at a suitable capacity of a specific lathe is- related to but not angle. necessarily limited *o the size of the table. A 30-inch vertical lathe (fig. 10-42) can hold and The side turret and side head of the vertical machine (using both the main and the side turret lathe correspond to the square turret and turrets) a workpiece up to 34 inches in diameter. cross-slide of the horizontal turret lathe. A If only the main turret is used, the workpiece typical vertical turret lathe hasa system of feed can be as large as 44 inches in diameter. trips and stops which function similarly to those on a horizontal turret lathe. In addition, the The main difference between the vertical machine has feed disengagement devices to turret lathe and the horizontl turret lathe is in prevent the heads from going beyond safe the design and operating features of the main maximum limits and bumping into each other. turret head. Refer to figure 10-42. Note that the turret slide (2) is mounted cm a swivel plate (3) Vertical turret lathes have varying degrees of which is attached to the saddle (4). The swivel capabilities, including feed and speedranges,

10-27 2 %:t9 ti MACHINERY REPAIRMAN 3 & 2

speed is often required due tothe large and odd-shaped sizes of work doneon vertical turret lathes in Navy machine shops. Ahigh speed could cause a workpiece to bethrown out of the machine,causingconsiderableequipment damage and possible injury to themachine operator or bystanders. One of -the major differences inoperator controls between the earlier (fig. 10-42)and the later (fig. 10-43) model verticalturret lathes is in the method used to position thecutter to the work. Earlier models havea handy,' 'el for manually positioning the cutter;later iiodels have an electric drive controlledby a lever. When the feed control lever is movedto the creep position, the turret head moves in the direction selected in incrementsas low as 0.0001 inch per minute. Thiscreep feed is independent of table revolution andcan be made with the table stopped. An attachment availableon some machines permits threading witha single point tool of up (1) Main turret head 10'32 threads per inch. Thegears, as specified by (2) Turret slide the lathe manufacturer, are positionedin the (3) Swivel plate attachment to provide a given ratiobetween the (4) Saddle revolutions per minute of the table andthe rate (5) Main rails of advance of the tool. (6) Upright bedways The same attachment also lets theoperator (7) Side turret turn or bore an angle of 1°to 45° in any (8) Side head. quadrant by positioning certaingears in the gear train. The angle is then cut byengaging the correct feed lever. 28.170X Details for turning tapers Figure 10.42. A 30inch vertical turretlathe. on a vertical turret lathe without this attachmentare given later in the chapter. angular turning limits and specialfeatures, such as threading. TOOLING VERTICAL You can expect to finda more coarse TURRET LA IMES minimum feed on the earlier modelsof vertical turret lathes. Some models havea minimum of The principles involved in theoperation of a 0.008 inch per revolution of the tableor chuck, vertical turret lathe are not while other models willgo as low as 0.001 inch very different from per revolution: The maximum feeds obtainable those just described for the horizontalturret lathe. The only significant differencebetween vary considerably also; however, this isusually. less of a limiting factor in job application. the machines, aside from themachine being vertical,isin the main turret. As previously The speeds available mentioned, you can feed themain head, which on any given vertical corresponds to the hexagonalturret of the turret lathe tend to be much slowerthan those horizontal available on a horizontal lathe. This machine,verticallytowardthe reduction of headstock (down); horizontally;or at an angle,

10-28 Chapter 10TURRET LATHES AND TURRET LATHEOPERATIONS

Figure 1043.A 38-inch vertical turret lathe.

10-29 2 MACHINERY REPAIRMAN 3 & 2 either by engaging both the horizontal and typical valve seat refacing job in progress ina vertical feeds or by setting the turret slide atan vertical turret lathe. Figure 10-45 shows the angle from the vertical and using the vertical double tooling principle applied to a machining feed only. operation. The tool angles for the cutters of the vertical The tooling principles and the advantage of machine correspond to those used on cutters in usingcoolantsforcuttingaspreviously thehorizontalb.., retlatheandarean describedfor horizontal turret lathes apply important factor in successful cutting. Also, the equally to vertical machines. same importance is attached to setting cutters on center ant! maintaining the clearance and rake argles in the process. Again,we cannot TAPER TURNING ON A overemphasize the importance of holding the VERTICAL TURRET LATHE cutters rigidly. In vertical turret lathe work, you must often The following information regarding taper use offset or bent shank cutters, special sweep turning on a vertical lathe is basedon a Bullard tools, and formingtools,particularly when vertical turret lathe. (See fig. 10-42). machining odd-shaped pieces. Many such cutting There are several ways to cut a taperon a tools are designed to take advantage of the great vertical turret lathe. You can cuta 45° taper flexibility of operation provided in the main with either a main turret-held cutteror a side head. head-held cutter by engaging the vertical and In a repair ship, the vertical turret lathe is horizontal feeds simultaneously. To cut a taper normally used for jobs other than straight of less than 30° with a main turret-held tool, set production work. For example, a large valvecan the turret slide for the correct degree of taper be mounted on the horizontal face of it and use only the vertical feed for the slide. The worktable or chuck much more conveniently operation corresponds to cutting a taper by than in almost any other type of machine used using the compound rest on an engine lathe; the to handle large work. Figure 10-44 showsa only differenceisthat you use the vertical

2C.194 Figure 10-44.Refacing a valve seat in a vertical turret 28.195 lathe. Figure 10-45.Double tooling.

26'0 10-30 Chapter 10TURRET LATHES AND TURRET LATHEOPERATIONS power feed instead of advancing the cutter by For angles greater than 45° and manual feed. not more than 60°, swivel the head in thesame direction as the taper angle being turned. (See fig. 10-47). By swiveling the main turret head, you can The formula for determining theproper angle is cut 30° to 60° angles on the verticalturret lathe ANGLE A = 2B°- 90°. A sample problem without the use of special attachments.To from figure 10-47 follows: machine angles greater than 30° andless thaii 60° from the vertical,engage both horizoAtal Formula A = 2B° - 90° feed and the vertical feed simultaneously2nd swivel the 1 .ad. The angle to whichyou swivel Example B = 56 the head is determined in the followingmanner. For angles between 30° and 45°, swivelthe head Therefore A = (2 X 56°)- 90° in the direction opposite to thetaper angle being turned,asillustratedinfigure10-46. The A = 112° - 90° formula for determining theproper angle is A = 90° - 2B°. A sample problem from figure /ANGLE A = 22° 10-46 follows:

Formula In connection with taper turning bythe A = 90°- 2B° main turret slide swiveling method,you must Example B = 35° use great care to set the slide in a true vertical position after completing the taper work Therefore A = 90°- (2 X 35) and A = 90°- 70° ANGLE A = 20°

L..

28.316X 28.317X Figure 10-16.Head setting for 30° to 45° angles. Figure 10-47.Head setting for 45° to 60 angles.

10-31 LI , MACHINERY REPAIRMAN 3 & 2 before using the main head for straight cuts. A Still another means of cuttingtapers with very small departure of the slide from thetrue either a main head-heldor side head-held tool is vertical will produce a relativelylarge taper on to use a sweep-type cutter ground and straight work. Unless you set to the' are alert to this, you desired angle. Then feed it straight to thework may inadvertently cut a dimension undersize to produce the desired tapered shape. This,of before you are aware of theerror. course, is feasible only for short taper cuts.

2 c;'30-32 CHAPTER 11

MILLING MACHINES AND MILLINGOPERATIONS

The milling machine removes metal witha plaintype,andtheverticalspindletype. revolving cutting tool called a milling cutter. Wherever only one type of machircs can be With various attachments, milling machinescan installed, the universal type is usually selected. be used for boring, slotting, circular milling, The UNIVERSAL MILLING MACHINE dividing, and drilling; cutting keyways, racks, (fig. 11-1) has all the principal features of the and gears; and flutbg taps and reamers. other types of milling machines. It can handle Bed type and knee and column type milling practically all classes of milling work. Youcan machines are generally found in most Navy take vertical cuts by feeding the tableup or machine shops. The bed type milling machine down. You can move the table in two directions has averticallyadjustablespindle.The in the horizontal plane: either at right anglesto horizontal boring mill discussed later in this chapter is representative of the 11;c1 type. The and d column milling machinkhas a fixed INNER ARBOR ARBOR SPINDLE NOSE spindle and a vertically adjustable table. There SUPPORT are several classes of milling machines within OVERARM COLUMN these types but only those classes with which OUTER DIVIDING you will, be concerned are discussed in this ARBOR HEAD SUPPORT- chapter. ENDLOSED You must be able to set up the milling DIVIDING HEAD LEAD DRIVE machine to machine flat, angular, and formed TAILSTOCK MECHANISM surfaces. Included in these jobs are milling keyways, milling hexagonal and square headson TABLE 41_ nuts and bolts, milling T-slots and dovetails, and milling spur gear teeth. To setup a milling machine, you must compute feeds and speeds, TABLE SWIVELS select and mount the proper holding device, and HERE select and mount the proper cutter to handle the job. SADDLE Like other machines in the shop, milling machines have manual and power feed systems, a selective spindle speed range and a coolant system. KNEE BASE

KNEE AND COLUMN MILLING ELEVATION SCREW MACHINES

The Navy uses three types of knee and 28.362 column milling machines: the universal type, the Figure 11-1.Universal milling machine. MACHINERY REPAIRMAN 3 & 2 the axis of the spindle or parallel to the axis of of the features foundon the other machines. the spindle. The principal advantage of the You can move the table in three directions: universal mill over the plain mill is thatyou can longitudinally (at right angles to the spindle), swivel the table on the saddle. Thus,you can transversely(paralleltothespindle), and move the table in the horizontal plane at an vertically (up and down). The ability ofthis angle to the axis of the spindle. This machine is machine to take heavy cuts at fast speedsis its used to cut most types of gears, milling cutters, chief value which is made possible bythe and twist drills, and is used for various kinds of machine's rigid construction. straight and taper work. The VERTICAL SPINDLE MILLING The PLAIN MILLING MACHINE isthe MACHINE (fig.11-2) has the spindle ina simplest milling machine since it has onlya few vertical position and at a right angleto the

STARTING LEVER VERTICAL HEAD CLAMP FOUR POSITION TURRET STOP

POWER FEED ENGAGING FOR VERTICAL HEAD ARBOR-LOC SPINDLE NOSE VERTICAL HEAD HANDWHEEL SPEED CHANGE DIAL

AUTOMATIC BACKLASH SPEED ELIMINATOR KNOB CALCULATOR

SPINDLE REVERSE LEVER FRONT TABLE FEED ENGAGING CROSS FEED ENGAGING LEVER TABLE TRAVERSE RAPID HANDWHEEL TRAVERSE LEVER

CROSS FEED AUTOMATIC HANDWHEEL LUBRICATION

FEED DIAL KNEE CLAMP

VERTICAL FEED REAR TABLE FEED HANDCRANK ENGAGING LEVER VERTICAL FEED ENGAGING LEVER TELESCOPIC COOLANT RET')RN OIL FILTER

28.363 Figure 11-2.Vertical spindle milling machine.

11 -2 2rH Chapter 11MILLING MACHINES AND MILLINGOPERATIONS surface of the table. The spindle hasa vertical SPINDLE movement,andthetablecanbe moved STARTING LEVER vertically, longitudinally, and transversely. Both OVERARM CLAMPS BACKLASH ELIMINATOR thespindleandtablemovement canbe O IIARM ENGAGING KNOB POSITIONING con trolledmanuallyorbypower.The SHAFT Vertical-spindle milling machine can be used for POWER TABLE TABLE MD LEVER facemilling,profiling,die sinking, and for TRAVERSE rt" HA N OWN EEL POWER CROSS various odd-shaped jobs; itcan also be used to FEED LEVER advantage in boring holes. Various small vertical CROSS iTRAVERSE spindle milling machines (fig.11-3) are also HANOWNEEL available for light precision milling operations. RAPID TRAVERSE LIVER MAJOR COMPONENTS

You must know the name andpurpose of Mar each of the main parts of a milling machineto understand the operations discussed later inthis chapter. Keep in mind that, althoughwe are discussing a knee and a column milling machine, you can apply most of the information to the other types. Figure 11-4, which illustratesa

TILT LOCK SCRIM e-WININI MAKI VERTICAL HANDCRANK GUARD FEED CHANGE CRANK AND DIAL MAD REAR POWER TABLE OVIR Alii FEED LEVER ROTOR MD NAIIOIWUL SPINDLE SPEED POWER VERTICAL ___11111 SELECTOR DIAL FEED LEVER DIPTN STOP LL SPINDLE MOTOR IASI 28.366 UNTIL LOCK KIM Figure 11-4.Plain milling machine, showingoperation PITCH com-nis (Cincinnati Milling Machine Co.). LONGITUDINAL TRAM. --Nkm CMS SLIM FALL MIN mannarum 11011 LOCI FALL CRANK KM LIFT GUM plain knee and column milling machineand COLUMN figure 11-5, which illustratesa universal knee MU LIFT San and column milling machine, will helpyou to become familiar with the location of theparts. COLUMN: The column including the base, is the main casting which supports allthe other parts of the machine. An oil reservoir anda CARNET pump in the column keep the spindle lubricated. The column rests on a base thatcontains a coolant reservoir and a pump thatyou can use when performing any machining operationthat requires a coolant. 28.364 Figure 11-3.Small verticalmilling machine(Atlas KNEE: The knee is the ,Asting that supports Press). the table and saddle. e d change gearing is 2:21 11-3 MACHINERY REPAIRMAN 3 & 2

dila* °

- .111111 PI) A

C

H

: I -

gar

11(

A. SPINDLE G. SPINDLE SPEED SELECTOR LEVERS M. KNEE ELEVATING CRANK B. ARBOR SUPPORT H. SADDLE AND SWIVEL N. TRANSVERSE HAND WHEEL C. SPINDLE CLUTCH LEVER I. LONGITUDINAL HANDCRANK D. SWITCH 0. VERTICAL FEED CONTROL J. BASE P. TRANSVERSE FEED LEVER E. OVERARM K. KNEE F. COLUMN 0. TABLE FEED TRIP DOG L. FEED DIAL R. LONGITUDINAL FEED CONTROL

Figure 11-5.Universal knee wid column millingmachine with horizontal spindle.

11-4 Chapter 11MILLING MACHINES ANDMILLING OPERATIONS

enclosed within the knee. It is supportedand TABLE: The table is the rectangular can be adjusted by the elevating screw. The knee casting located on top of the saddle. It containsseveral is fastened to the column by dovetailways. You T-slotsforfastening work or workholding can raise or lower the knee by either handor devices to it. Youcan move the table by hand power feed. You usually use hand feed to take or by power. To move the table by hand, the depth of cut or to position engage the work and and turn the longitudinal handcrank.To move it power feedto move the work during the by power, engage the longitudinal machining operation. directional feedcontrollever.You canpositionthe longitudinal directional feed control leverto the SADDLE and SWIVEL TABLE: The saddle left, to the right, or in the center.Place the end slides on a horizontal dovetail (whichis parallel to the axis of the spindle) of the directional feed control leverto the left on the knee. The to feed the table toward the left. Place itto the swivel table (on universal machinesonly) is attached to the saddle and right to feed the table toward the right.Place it can be swiveled in the center posi -to" disengage the power approximately 45° in either direction. feed -or-toethe table by hand. POWER FEED MECHANISM: The power SPINDLE: The spindle holds and drivesthe feed mechanism is contained inthe knee and various cutting tools. It is controls the longitudinal, trapsverse (in a shaft mounted on and out) bearings supported by the column.The spindle and vertical feeds. Youcan obtain the desired is driven by an electric motor rate of feed on machines, such through a train or as the one shown gears all mounted within the column. The front in figure 11-4 b poitioning the feedselection end of the spindle, which is le near the table, has as indicated on the feed selection plate. an internal taper machined in it. The internal On machines such as theone in figure 11-5, you taper (3 1/2 inches per foot) permits get the feed you want by turning the you to speed mount tapered-shank cutter holders andcutter selection handle until the desiredrate of feed is arbors. Two keys, locatedon the face of the indicatedonthefeeddial.Most milling spindle, provide a positive drive machines have a rapid traverse lever that for the cutter you can holder, or arbor. Yousecure the holder or arbor engage when you want to temporarily increase in the spindle by a drawbolt and the speed of the longitudinal, jamnut, as transverse, or shown in figure11-6. Large face millsare vertical feeds. For example,you would engage sometimes mounted directly to the spindlenose. this lever when positioningor aligning the work. NOTE: For safetyreasons, you must exercise OVERARM. The overarm is thehorizontal extremecaution whileusing rapidtraverse controls. beam to which you fasten thearbor support. The- overarm (fig. 11-5)may be a single casting

JAMNUT

-r intiontlimatto 311013110

DRAWBOLT

28.367 Figure 11-6.Spindle drewbolt.

11-5 0/1- MACHINERY REPAIRMAN 3 & 2

that slides in dovetail ways on the top of the SIZE DESIGNATION: All milling machines column. It may consist of one or two cylindrical areidentifiedbyfourbasicfactors:size, bars that slide through ho'.es in the column,as horsepower, model, and type. The size ofa shown in figure 11-4. To position theoverarm milling machine is based on the longitudinal on some machines, first unclamp locknuts and (fromlefttoright) table travel in inches. then extend the overarm by turninga crank. On Vertical, cross, and longitudinal travelare all others, you move the overarm by simply pushing closely related as far as overall capacity. For size on it. You should extend the overarm only far desigr,ation, only the longitudinal travel is used. enough to position the arbor supportto make There, are six sizes of knee type milling machines the setup as rigid as possible. To placearbor with each number representing the number of supports (B in fig. 11-5) on an overarm suchas inches of travel. the one shown in figure 11-5, extendone of the bars approximately 1 inch farther than theother Standard Size Longitudinal Table Travel bar. Tighten the locknuts after positioning the overarm. On some milling machines the coolant No. 1 22 inches supply nozzle is fastened to theoverarm. You can mount the nozzle with a split clamp to the No. 2 28 inches overarm after you have placed the arbor support in position. No. 3 34 inches

ARBOR SUPPORT: The arbor support isa No. 4 42 inches casting that contains a bearing which aligns the outer end of the arbor with the spindle. This No. 5 50 inches helps to keep the arbor from springing during cutting operations. Two types of arbor supports N. 6 60 inches are commonly used. One type has a small diameter bearing hole usually 1-inch maximum If the milling machine inyoar shopis diameter. The other type hasa large diameter labeled No. 2HL, it has a table travel of 28 bearing hole usually up to 2 3/4 inches.An oil inches; if it is labeled No. SLD, it hasa travel of reservoir in the arbor support keeps the bearing 50inches.The MODEL designationis surfaces lubricated. You can clampan arbor determined by the manufacturer, and features support any place you want on theoverarm. vary with different brands. The TYPE of milling Small arbor supports give additionalclearance machine isdesignated, as plain or universal, below the arbor supports when you are using horizontal or vertical, and knee and columnor small diameter cutters. Small arborsupports can bed. In addition, machinesmay have other provide support only at the extreme end ofthe special type designations. arbor.Forthisreasontheyarenot recommended for general use. Youcan position Standard equipment with milling machines large ,arbor supports atany point on the arbor. used in Navy ships includes workholding Therefore, they can provide support devices, near the spindle attachments, cutters, arbors, andany cutter, if necessary. For thisreason, you should special tool needed for settingup the machine position the large arbor supportas close to the for milling. This equipment allows for holding cutter as possible to provide a rigid tooling and cutting the great variety of milling jobsyou setup.Althougharborsupportsarenot will encounter in Navy repair work. classified, a general rule of thumbcan be used by the size of the arbor used. For example,old reference type A is small bearing diameter and WORICHOLDING DEVICES old reference type B is large bearing diameter. NOTE: Before looseningor tightening the arbor Thefollowingmaterialdescribes nut, you must install the arbor support. This will workholding devices which youmay be required prevent bending or springing of the arbor. to use.

11-6 Chapter 11MILLING MACHINESAND MILLING OPERATIONS workholding setup. It is used when thesurface to be machined must be parallel to thesurface Thevisescommonly usedonmilling seated in the vise. The swivelviseis used machines are the flanged plain vise, theswivel similarly to the flanged vise, but the vise, and the toolmaker's universal setup is less vise (fig. rigid;the workpiece can be swiveled ina 11-7).Theflanged viseprovidesarigid horizontal plane to any required angle.The toolmaker's universal viseis used when the workpiece must be set up ata complex angle in relation to the axis of the spindle andto the table surface.

).` 'sr INDEXING EQUIPMENT

Indexing eqiupment (fig.11-8) is used to hold the workpiece and to providea means of turning the workpiece so thata number of accurately' spaced cuts can be made (gearteeth for example). The workpiece is heldin a chuck, attachedtothedividing headspindle,or between a live center in the dividingindex head and a dead center in the footstock;collets are also used. The center restcan be used to support long slender work. Youcan raise or lower the center of the footstock for settingup tapered workpieces.

Dividing Head

The internal components ofthe dividing head are shown infigure11-9. The ratio between the worm andgear is 40 to 1. By turning the wormone turn, you rotate the spindle 1/40 of .a revolution. The indexplate has a series of concentric circles of holes. Withthe index plate you can accuratelygage partial turns ofthe worm shaftandturn the spindle accurately in amounts smallerthan 1/40 of a revolution. You can secure the indexplate either to the dividing head housingor to the worm shaft. YoU can adjust the crankpinradially for use in any circle of holes. Youcan set the sector arms to span any number of holes in theindex plate to provide a guide forrotating the index crank for partialturns. You can turn the dividing head spindledirectly by hand by disengaging the worm and drawingthe plunger back, or by the index crankthrough the worm and worm gear. 28.199X The spindle is set ina swivel block so that Figure 11-7.Milling machine vises. you can 'setthe spindle at any angle from MACHINERY REPAIRMAN 3 & 2

'DIVIDING' HEAD BRACKETS FOR MOUNTING CHANGE FOOTS TOCK GEARS CENTER REST

DIVIDING HEAD CENTER [CHUCK' [ DRIVING DOG

INDEX PLATES CHANGE GEARS

28.200X Figure 11-8.Indexing equipment.

slightly below horizontal to slightly past vertical. There is an index plate that usually has SECTOR ARM INDEX DIVIDING WORMGEAR a 24-inch HEAD SPINDLE hole circle. Place it back of the chuckor center PIN (40TEETH) so that you can index the spindle rapidly by hand for commonly required divisions. Most index heads have a 40-1 ratio. One well-known exception has a 5 to 1 ratio (see fig. 11-10). This INDEX ratio is made possible by a 5 to 1 hypoid bevel CRANK gear ratio between the index crank and the dividing head spindle. The faster movement of the spindle with one turn of the index crank WORM permitsspeedier INDEX WORM production.Itisalso an SECTOR ARM PLATE SHAFT advantage in truing work or testing work forrun out with a dial indicator. Although made to a high standard of accuracy, the 5 to 1 ratio dividing head does not permit as widea selection 28.201 of divisionsbysimple indexing operation. Figure 11-9.Dividing head mechanism.

11-8 21iCai Chapter 11MILLING MACHINES ANDMILLING OPERATIONS

28.388 Figure 11-10.Universal spiral dividinghead with 5 to 1 ratio between spindle and indexcrank. (Kearney & Trecker Corp.)

Differential indexing can be used on the 5 to 1 28.307 ratio dividing head bymeans of a differential Figure 11-11.Enclosed driving indexing attachment. mechanism. The dividing head may also be gearedto the lead screw of the milling machine by a driving LOW LEAD DRIVE.Forsome models and mechanism and will imparta rotary motion to the workas required makes of milling machinesa low lead driving for helical and spiral mechanismisavailable; however, additional milling. The index headmay have one of several parts must be built into the machine driving mechanisms. The most at the common of these factory. This driving mechanism hasa lead range isthe ENCLOSED DRIVING MECHANISM of 0.125 to 100 inches. which is standard equipmenton some makes of the plain and universal knee and columnmilling LONG AND SHORT LEAD DRIVE. When machines. The enclosed driving mechanism has a an extremely long or short lead is required,you lead range of 2 1/2 to 100 inches andis driven can use the long and short lead attachment (fig directly from the lead screw. 11-12). As with the low lead drivingmechanism, Gearing Arrangement the milling machine, must have certairiparts built intothe machineatthefactory.Inthis Figure 1 1-1 1 illustratesthegearing attachment, an auxiliary shaft in the table drive arrangement used on most milling machines. The mechanism supplies power through thegear gears are marked as follows: train to the dividing head. It alsosupplies the power forthetablelead screw which is A = Gear on the worm shaft (driven) disengaged from the regular drivewhen the attachment is used. This attachment B = First gear on the idler stud (driving) provides leads in the range between 0.010and 1000 C = Second gear on idler stud (driven) inches. D = Gear on lead screw (driving) CIRCULAR MILLING ATTACHMENT. E and F = Idler gears The circular milling attachment,or

11-9 2,97 MACHINERY REPAIRMAN 3 & 2

128.27X Figs* 11-12.The long and short lead attachment.

(fig. 11-13), is used for settingup work that of the milling machine. Thecutter can be must be rotated in a korizontal plane. The secured in the spindle of the attachment worktable is graduated t 1,2° to 360°) around and its then can be set by the two rotary swivelsso that circumference. You cat tarn the table by hand the cutter will cut at any angle to the horizontal or by the table feed mechanism througha gear or the vertical plane. The spindle of the universal train (fig. 11-13). An 80 to 1 worm and gear millingattachmentisdrivenbygearing drive contained in the rotary table andindex connected to the milling machine spindle. plate arrangement makes this device usefulfor accurate indexing of horizontal surfaces. SLOTTING ATTACHMENT

SPECIAL ATTACHMENTS Although special machinesare designed for cutting slots (such as keyways andsplines), this The universal milling (head)attachment, type machinefrequentlyisnot shown in figure 11-14, is clamped available. to the column Consequently, the machinist must deviseother

11-10 2!) Chapter 11MILLING MACHINES ANDMILLING OPERATIONS

,

126.29X Figure 11-13.Circular milling attachment,power feed mechanism, and vertical milling attachment. means. The slotting attachment in figure 11-15, reciprocating motion of the tool slideon the when mounted on the column and spindleof a slotter, similar to the ramon a shaper. A single plain or universal milling machine, will perform point cutting tool is used. Since the toolslide such operations. can be swiveled through 3600, slotting The attachment can be is designed so that the done at any angle, and the strokecan be set rotating motion of the spindle ischanged to from 0 to 4 inches.

11-11 2!), MACHINERY REPAIRMAN 3 & 2

sj UNIVERSAL MILLING ATTACHMENT

CIRCULAR MILLING ATTACHMENT (ROTARY TABLE)

-2.2VAVa

AL

28.202X, Figure 11-14.Circular milling attachments (rotarytable) and universal (head) attachment.

INDEXING THE WORK DIRECT INDEXING

Indexingisdone by thedirect,plain, Direct indexing, sometimes referredto as compound, or differential methods. The direct rapidindexing,isthe simplest method of and plain methods are the most commonlyused; indexing. Figure 11-16 shows thefront index the compound and differentialare used only plate attached to the work spindle. Thefront when the job cannot be done by plainor direct index plate usually has 24 equally spaced indexing. holes. These holes can be engaged by thefront index

11-12

.3!11-.) Chapter 11MILLING MACHINES AND MILLINGOPERATIONS

pin, which is spring-loaded and moved inal out by a small lever. Rapid indexing requir 4 that the worm and worm wheel be disengaged thatthespindlecan be moved by han Numbers that can be divided into 24can 1 indexed in this manner. Rapid indexing is use when a large number of duplicate parts are tot milled.

To find the number of holes tomove in ti indexplate,divide 24 by the number divisions required.

24 Number of holes to move =Tr- where N required number of N divisions

Example: Indexing for a hexagon head bol

because a hexagon head has six flats,

24-an N = 4 holes

211.3011 flew. 11.11. pottinga bushing using a dotting IN ANY INDEXING OPERATIOI eiteehosent. (Cincinnati Milling Machine CO ALWAYS START COUNTING FROM TH HOLE ADJACENT TO THE CRANKPIN` During heavy cutting operations, clamp th spindle by the clamp screw to relieve straina LIMY MIM the index pin. KATE , , '°'

PLAIN INDEXING

Plain indexing, or simple indexing, isuses when a circle must be divided intomore part thanispossible by rapid indexing. Simpi indexing requires that the spindle be moved b: turning an index crank, which turns theworn that is meshed with the worm wheel. The ratil between worm and worm wheelt1 to 41 (1:40). Onc turn of the index c turns till WM head spindle 1/40 of aco. plateplate turn Forty kits of the index crank will revolve du spindle chock and Job one complete turn. n 211.20X determine the number of turns or fractions Ilfore 11.111.DIrest index plats. parts of a turn of the index crank necessary tc

11.13 3u',/ MACHINERY REPAIRMAN 3 & 2 cut any required number of divisions, divide 40 on thetypicalindexing job. For example, by the number of divisions required. indexing for 18 divisiond

40 Number of turns of the index crank = 140 2 F48-turns

where N = number of divisions r,-ired The whole number indicates the complete Example (1): Index for five divisions turns of the index crank, the denominator of the fraction represents the index circle, and the numerator represents the number of holes to use e+0 8 on that circle. Because there is an 18-hole index circle, the mixed number 2 4/18 indicates that There are eight turns of the crank for the index crank will be moved 2 full turns plus 4 each holes on the 18-hole circle. The sectorarms are division. positioned to include 4 holes and the hole in which the index crank pin is engaged. The Example (2): Index for eight divisions number of holes (4) represents the movement of the index crank; the hole that engages the index .42.4_0. crank pin is not included. N 8 When the denominator of the indexing fraction is smaller or larger than the number of Example (3): Index for ten divisions holes contained in any of the index circles, change it to a number representingone of the circleof holes. Do this by mulitplyingor 40 4 turns dividing the numerator and the denominator by N 10 the same number. For example, to index for the machining of a hexagon (N = 6): When the number of divisions required does not divide evenly into 40, the index crank must 40 4 be moved a fractional part of torns a turn with index N 6 6 pates. A commonly used index headcomes with three index plates, Eath plate has six circles of In its simplest form, this is 6 2/3 turns. The holes which we shall use as an example. denominator 3willdivide equally into the following circles of holes: Plate one: 15-16-17-18-19-20 Plate one 15 and 18 Plate two: 21-23-27-29-31-33 Plate two 21 and 33 Plate three: 37-39-41-43-47.49 Plate three, 39

The previous examples of the use of the If plate 3 is convenientlyon the index head, 40 indexing formula gave results in complete you should useit. You must multiply the denominator 3 by 13 to equal 39. In ordernot turns of the index crank. This seldom happens to change the value of the original indexing

11-14 3 , 19 Chapter 11MILLING MACHINES ANDMILLING OPERATIONS fraction, you must multiply both the numerator If an 18-hole circle is used, thefraction becomes and the denominator by 13 4 2 8 9 2 18For each division turn the crank 4 2 13 26 2 26 turns and 8 holes on an 18-hole circle. X = = 6 3 13 39 63 39 Example 2: Index for 136 divisions. Thus, to mill each side of a hexagon, you must 40 40 5 move the index crank 6 full turns and 26 holes N 136 17 on a 39-hole circle.

When the number of divisions exceeds40, There is a 17-hole circle,so for each division you may divide both terms of the fraction bya turn the crank 5 holes on a 17-hole circle. common divisor to obtain an index circle that is available. For example, if 160 divisionsare CAUTION: In setting the sectorarms to required, N = 160; the fraction to beused is space off the required number of holes on the index circle, do not count the holethat the 40 40 index crank pin is in. N 160 Most manufacturers provide differentplates for indexing. Late model Brown andSharpe Because there is no 160-hole circle thisfraction index heads use two plates with thefollowing must be reduced. circle of holes. Plate one: 15, 16, 19,23, 31, 37, 41, 43, 47, Plate two: 17, 18, 20, 21,27, 29, 33, 39, 47. The standard index plate suppliedwith 40/10 4 the Cincinnati index head is provided 160/10 rg with 11 different circles of holeson each side. Turn 4 holes on the 16-hole circle. Side one: 24-25-28-30-34-37-38-39-41-42-43 Side two: 46-47-49-51-53-54-57-5C-59-62-66 It is usually more convenientto reduce the original fraction to its lowest terms andmultiply ANGULAR INDEXING both terms of the fraction bya factor that will give a number representinga circle of holes. When you must divide work intodegrees or fractions of degrees by plain indexing,remember 40/40 that one turn of the index crankwill rotate a 160/40 4 point on the circumference of the work 1/40of a revolution. Since there are 360° ina circle, one 1 4 4 turnof theindex crank willrevolve the 71 ^71=V circumference of the work 1/40 of 360°,or 9°. Hence, in using the index plate andfractional The following examples will further clarifythe parts of a turn, 2 holes inan 18-hole circle equal use of this formula. 1°, 1 hole in a 27-hole circleequals 2/3°, 3 holes in 54-hole circle equal 1/3°. Todetermine the Example 1: Index for 9 divisions. number of turns and parts ofa turn of the index crank for a desired number ofdegrees, divide the number of degrees by 9. Thequotient will represent the number of completeturns and Act fractions of a turn that N 9 9 you should rotate the index crank. For example, thecalculation for

11-15 MACHINERY REPAIRMAN 3 & 2

determining 15° when an index platewith a If a quotient is not approximately 54-hole circle is available, is equal to as follows: an available circle of holes, multiply byany trial number which will give a product equal 15_, 6 , 6_ ,36 to the - -6-- 371 ntr.nber of holes in one of the availableindex circles. You can thenmove the crank the or one complete turn plus 36 holeson ';ho required number of holes to give thedesired 54-hole circle. The calculation for determining division.For example,thecalculationfor 13 1/2° when an index plate withan 18-hole determining 54 minutes whenan index plate circle is available, is as follows: that has a 20-hole circleisavailable,is as follows: 13.5 4.5 2 9 9 2 18 54 1 v 2 2 (no. of holes) 540 10 or one complete turn plus 9 holes on the 18-hole 20 (20-hole circle) circle.' or 2 holes on the 20-hole circle. When indexing angles are given inminutes andapproximatedivisionsareacceptable, movement of the index crank and theproper COMPOUND INDEXING index plate may be determined by thefollowing calculations. You can determine thenumber of minutes represented byone turn of the index Compound indexing is a combination oftwo crank by multiplying the number ofdegrees covered in one turn of the index crank plain indexing procedures to indexa number of by 60: divisions beyond therange of plain indexing. 9° X 60' = 540' One number of divisions is indexedusing the standardplainindexingmethod;another Therefore, one turn of the index crankwill number of divisions is indexed by turningthe rotate the index head spindle 540 minutes. index plate (leaving the crank pin engagedin the The number of minutes (540) dividedby the hole as set in the first indexingoperation) by a number of minutes in the divisiondesired, required amount. The differencebetween the indicates the total number of holes thereshould amount indexed in the first operation andthe be in the index plate used. (Movingthe index amount indexed in the second operation results stank one hole will rotate the index head spindle in the spindle turning the requiredamount for Ifisough thedesired number of minutes of the number of divisions. Compoundindexing is angle.) This method of indexingcan be used seldom used because (1) differentialindexing is only for approximate angles sinceordinarily the easier, (2) high number index platesare usually quotient will come out in mixed numbersor in availableto provide any range of divisions numbers for which thereare no index plates normally required and (3) thecomputation and available. However, when the quotient isnearly actual operation are quite complicatedmaking it equal to the number of holes inan available easy for errors to be introduced. index plate, the nearest number of holescan be used and the error will bevery small. For Compound indexing is brieflydescribed in example, the calculation for 24 minuteswould the following example. To index99 divisions be: proceed as follows:

540 22.5 1.Multiplytherequirednumberof 24 divisions by the difference betweenthe number of holes in two circles selected or oneone hole on the 22.5-hole circle. Since there at random. Divide this product by 40 (ratioof spindle to is no 22.5-hole circleon the index plate, a crank) times the product of 23-hole circle plate would he used. the two index hole circles.Assume that the 27-hole circleand

11-16 3 LI 4 Chapter 11MILLING MACHINES AND MILLINGOPERATIONS

22-hole circle have been selected. The resulting Figure 11-17 shows a dividing headset up equation is: for differential indexing. The indexcrank is turned a., for plain indexing, thus turningthe 99 X (33- 27) 99 X 6 spindle gear and then the compoundgear and 40 X 33 X 27 40 X 33 X 27 idler to drive the gear whichturns the index plate.Specific procedures for installing the 2. To make the problem easier to solve, gearing andarrangingthe index platefor factor each term of the equation into its lowest differential indexing (and compoundindexing) prime factors and cancel where possible. For are given in manufacturers' technical manuals. example: To index 57 divisions for example, take the (1 X3 Xn)(3 X/) 1 following steps: (2X 2X 2X 5)(il X1)(1 X1 X3)60 1.Select a number greater or lesser than the required number of divisions for whichan The result of this process must be in the form of availableindexplatecanbe used (60 for a fraction as given (that is,1 divided by some example). number). Always try to select the two circles which will have factors that cancelout the 2. The number of turns for plain indexing factors in the numerator of the problem. When 60 divisionsis:40/60 or 14/2. which will she numerator of the resulting fraction isgreater require 14 holes in a 21-hole circle inthe index than 1, divide it by the denominator anduse the plate. quotient (to nearest whole number) instead of the denominator of the fraction. 3. To find the requiredgear ratio, subtract therequired number of divisions fromthe 3. Thedenominatoroftheresulting selected number or viceversa (depending on fraction derived in step two is theterm used to find the number of turns and holes for indexing the spindle and index plate. To indexfor 99 divisions, turn the spindle by an amount equal to 60/33 or one complete turn plus 27 holesin the 33-hole circle; turn the index plateby an amount equal to 60/27 or two complete turns /011111M.

plus 6 holes in the 27-hole circle. If theindex r, crank is turned clockwise, the index platemust be turned counterclockwise and viceversa. , V4.

DIFFERENTIAL INDEXING tf

Differential indexing Is similar to compound indexing except that the index plate isturned duringtheindexingoperationbygears connected to the dividing head spindle. Because the index plate movement is causedby the spindle movement, only one Indexing procedure is required, The gear train between thedividing head spindle and the index plate providesthe correct ratio of movement between the spindle and index plate. 28.210X Figure 1111.-0111wentlalIndexing.

11-17 .14.);) MACHINERY REPAIRMAN 3 & 2

which is larger), and multiply the resultby Wide Range Divider 40/60 (formula for index. ng 60 divisions). Thus: 40 In the majority of indexing operations, the gear ratio = (60 - 57) X = 3 X40 2 60 60T desired number of equal!', .paced divisionsmay be obtained by either director plain indexing. 3y using one or the other of these methods,you The numerator indicates the spindlegear; the may index up to 2,640 divisions. To increase the denominator indicates the drivengear. range of divisions, me the high number index 4.Select two gears that have a 2 to 1 ratio plates in place of the standard index plate.These (for example a 48-toothgear and a 24-tooth high number plates havea greater number of gear) circles of holes an 5. a greater range of holes in If the selected number is greater than the thecirclesthanthestandard plates.This actual number of divisions required,use one or increases the range of divisions obtainable from three idlers inthe simple gear train; if the 1,040 to 7,960. selected number is smaller,use none or two In some instances, you may need to index idlers. The reverse is true for compoundgear beyond the range ofany of these methods. To trains.Sincethe number is greater inthis further increasethe range, use a universal example, use one or three idlers. dividing head that has a widerange divider. This 6. Now turn the index crank 14 holesin type of indexing equipment enablesyou to the 21-hole circle of the index plate.As the index divisions from 2 to 400,000. crank turns the spindle, the The wide gear train turns the range divider (fig.11-18) consists of a large index plate slightly faster than the indexcrank. index plate with sectorarms and crank and a

A

I. 1-1, G

8

126.28X Figure 11.16. The wide range divider. Chapter 11MILLING MACHINES AND MILLING OPERATIONS small index plate with sectorarms and crank. index crank rotates the dividing head spindle The large index plate (A, fig. 11-18) has holes 1/40 of a turn, or 9°. By using the large index drilled on both sides and contains eleven circles plateandcrank,youcanindexinthe of holes on each side of the plate. The number conventional manner. Machine operation is the of holes in the circles on one sideare 24, 28, 30, same as it is with the standard dividing head. 34, 37, 38, 39, 41, 42, 43, and 100. Theother When the smallindex crank(D, fig. 11-18) is side of the plate has circles containing 46, 47, rotated, the large index crank remains stationary 49, 51, 53, 54, 57, 58, 59, 62, and 66 holes.The but the main shaft which drives the work small index plate has two circles of holes and is revolves in the ratio of 100 to1. This ratio, drilled on one side only. The outer circle has superimposed on the 40 to 1 ratio between the 100 holes and the inner circle has 54 holes. worm and worm wheel (see fig. 11-19), causes The small index plate (C, fig. .11-18) is the dividing head spindle to rotate in the ratio of mounted on the housing of the planetary gearing 4,000 to 1. This means, then, thatone complete (G,fig.11-18) which is built into the index revolution of the spindle will require 4,000 turns crank (B, fig. 11-18) of the large plate. As the of the small index crank. Turning the small index crank of the large plate is rotated, the crank one complete turn will rotate the dividing planetary gearing assembly and the small index head spindle 5 minutes, 24 seconds ofa degree. plate and crank rotate with it. If one hole of the 100-hole circleon the small As with the standard dividing head, the large index plate were to be indexed, the dividing index crank rotates the spindle in the ratio of 40 head spindle would make 1/400,000 ofa turn, to 1. Therefore, one complete turn of the large or 3.24 seconds of a degree.

CLAMPING STRAPS INDEX PIN SWIVEL BLOCK INDEX CRANK

SPINDLE MINI .L.

ECCENTRIC 4111,1,1,a NWAVI FOR DISENGAGING WORM I. 11.41

TRUNNION

WORM WHEEL I WORM INDEX PLATE

TABLE

28.370 Figure 11-19.Section through a dividing head showingworm, worm wheel, and worm shaft. (Cincinnati Milacron Co.)

11-19 MACHINERY REPAIRMAN 3 & 2

You can get any whole number of divisions, up to and including 60, and hundreds of others, FO'CKING PIN LEvEr`fi'176'''.7,4 ANGULAR by using only the large index plate and crank. SCALE AND ZERO MARK INDu PTE The dividing head manufacturer provides tables ARMOS R m listing many of the settings whichmay be read directlyfromthetablewith no further INDEX calculationsnecessary.Ifthenumber of CRANK divisions required is not listed in the tableor if thereare no tables,calculatethe required settingsinthefollowingmanner:Divide SECTOR ARM 400,000 by the number of divisions desired. The CLAMP result gives you a whole number quotient anda PLATE FOR SCREWS fraction. Set the sector arm of the large index DIRECT INDEXING

plate to the first two hole numbers ofthe WOR M quotient, and set the sector arm of the small S AFT NUT index plate to the last two numbers of the quotient. If the quotient results ina five-digit iAT number (instead of the usual four digits),the iFat 4.4 titi first number of the quotient determinesthe ,INDEX PLATE number of full turns of the large index crank. After you index both the large and thesmall cranks, you must compensate for the remaining 28.371 fraction.Add onespacetothe indexing Figure 11-20.Principal parts of a late model Cincinnati movement of the small crank at intervals equal universal spiral index head (Cincinnati Milacron Co.). to the first whole number you get by dividing1 by the remaining fraction. The indexing ofthe fraction will be slightly in erroro. a a small span CUTTERS AND ARBORS of divisions; however, the error isso slight as to be negligible. When performing a milling operation,you move the work into a rotating cutter. On most Adjusting the Sector Arms milling machines, the cutter is mountedon an arbor that is driven by the spindle. However,the spindle may drive the cutter directly. We To use the index head sector will arms, turn the discuss cutters in the first part of thissection left-hand arm to the left of the index pin which and arbors in the second part. is inserted into the first hole in the circle of holes that isto be used. Then loosen the setscrew (fig. 11-18E) and adjust the right-hand CUTTERS arm of the sector so that the correct number of holes will be contained between thetwo arms There are many different milling machine (fig. 11-20). After making the adjustments,lock cutters. Some cutters can be used for several the setscrew to hold the arms in position. When operations, while others can be used foronly setting the arms, count the required numberof one operation. Some cutters have straight teeth holes from the one in which the pin is inserted, and others have helical teeth. Somecutters have considering this hole as zero. By subsequentuse mounting shanks and others have mounting of the index sector, you will not needto count holes. You must decide which cutterto use. To the holes for each division. When using the index make this decision, you must be familiar crank to revolve the spindle, with you must unlock the various milling cutters and theiruses. The the spindle clamp screw; however, before cutting information in this section will help work held In or on the indeX head, lock you to the selectthepropercutterforthevarious spindle again to relieve the strain. operations you willbe performing. In this

11-20 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

section we will cover cutter types and cutter from either end), the cutter has right-hand teeth. selection. If the helix angle twists in a counterclockwise Standard milling cutters are made in many direction, the cutter has left-hand teeth. The shapes and sizes for milling both regular and teeth on staggered-tooth cutters are alternately irregular shapes. Various cutters designed for left-hand and right-hand. specific purposes also are available; for example, a cutter for milling a particular kind of curve on some intermediate part of the workpiece. Types and Uses Milling cutters generally take their names from the operation which they perform. Those commonly recognized are:(1) plain milling There are many different types of milling cutters of various widths and diameters, used cutters. We will now discuss these types and principally for milling flat surfaces whichare their uses. parallel to the axis of the cutter; (2) angular milling cutters, designed for milling V-grooves PLAIN MILLING CUTTER.You willuse and the grooves in reamers, taps, and milling plain milling cutters to mill flat surfaces thatare cutters; (3) face milling cutters, used for milling parallel to the cutter axis. As you cansee in flat surfaces at right angles to the axis of the figure 11-21, a plain milling cutter isa cylinder cutter; and (4) forming cutters, used for the with teeth cut on the circumference only. Plain production of surfaceswith some form of milling cutters are made in a variety of diameters irregular outline. and widths. Note in figure 11-22, that the cutter Milling cutters may also be classifiedas teeth may be either straight or helical. When the arbor-mounted,orshank-mounted. width is more than 3/4 inch, the teethare ARBOR-MOUNTED CUTTERS are mountedon usually helical. A straight cutter tool is parallel the straight shanks of arbors. The arbor is then to its axis. It cuts along its entire width at the inserted into the milling machine spindle. We same time, causing a shock as the tooth starts to will discuss the methods of mounting arbors and cut.Helicalteeth eliminatethis shock and cutters in greater detail later in this chapter. produce a free cutting action. A helical tooth begins the cut at one end and continuesacross Milling cutters may h.ve straight, right-hand, the work with a smooth shaving action. Plain left-hand, or staggered teeth. Straight teethare milling cutters usually have radial teeth. On parallel to the axis of the cutter. If the helix some coarse helical tooth cutters the tooth face angle twists in a clockwise direction (viewed isundercut to produce a smoother cutting

28.372 Figure 11.21:Plain milling cutter&

11-21 3j:j MACHINERY REPAIRMAN 3 & 2

RADIAL RELIEF PERIPHERAL ANGLE CUTTING EDGE

CLEARANC SURFACE itOr411111111114V TOOTH FACE LAND AXIAL RELIEF HEEL ANGLE FLUTE_ CLEARANCE ) SURFACE

RADIAL RAKE ANGLE (POSITIVE SHOWN ) */ Mvizio CONCAVITY OFFSET

FILLET LIP LIP ANGLE

FACE WIDTH

HELICAL TEETH

HELICAL RAKE ANGLE (L.H HELIX SHOWN )

RADIAL RAKE ANGLE (POSITIVE SHOWN) TOOTH FACE RADIAL RELIEF

TOOTH

FLUTE AXIAL RELIEF FILLET -

OFFSET

28.373 Figure 11.22. Milling cutter terms. action. Coarse teeth decrease the tendency of diameter of the cutter, width of thecutter, and the arbor to spring and give thecutter greater diameter of the hole in the cutter. strength. A plain milling cutter hasa standard size ar- SIDE MILLING CUTTER.The side or hole for mounting on a standard size arbor. milling cutter (fig. 11-23) is a plain millingcutter with the size of the cutter is designatedby the teeth cut on both sidesas well as on the 11 -22iii/ Chapter 11MILLING MACHINES AND MILLING OPERATIONS

I

28.375 Figure 11-24.Helf-side milling cutter.

standard size slots. The width is regulated by thin washers inserted between the cutters. METAL SLITTING SAW.You can use a 28.374 metal slitting saw to cut off work or to mill Figure 11.23. Side milling cutter. narrow slots. A metal slitting saw is similar to a plain or side milling cuttet. The face width is usually less than 3/16 inch This type of cutter periphery or circumference of the cutter. You can see that the portion of the cutter between usually has more teeth for 4 given diameter than the hub and the side of the teeth is thinner to give more chip clearance. These cutters are often used in pairs to mill parallel sides. This process is called straddle milling. Cutters more than 8 inchesindiameterareusually made with inserted teeth. The size designation is the same as for plain milling cutters.

HALF-SIDE MILLING CUTTER.Half-side milling cutters (fig. 11-24) are made particularly for jobs where only one side of the cutter isneeded. These cutters have coarse, helical teeth on one side only so that heavy cutscan be made with ease. SIDE MILLING CUTTER (INTERLOCKING).Side milling cutters whose 28.376 teeth interlock (fig. 11-25) can be used to mill Figure 11.25.Interlocking tooth side milling cutter.

11-23 3 1 1 MACHINERY REPAIRMAN 3 &2

A. 28.379 Figure 11-28.Slittingsaw with staggered teeth. 28.377 Figure 11-29.Metal slittingsaw. saws with staggered teeth, as shown infigure 11-28. These cuttersare usually 3/16 inch to 3/8 plain cutter. It is thinner at thecenter than at inch in thickness. he outer edge to giveproper clearance for milling deep slots. Figure 11-26 shows a metal SCREW SLOTTING CUTTER.The lifting saw with teeth cut inthe circumference screw f the cutter only. Some slotting cutter (fig. 11-29) is usedto cut shallow saws, such as the one in slots, such as those inscrew heads. This cutter Igure11-27, have side teeth whichachieve etter cutting action, breakup chips, and revent dragging whenyou cut deep slots. For FACE eavy sawing in steel, thereare metal slitting WIDTH -41 re-

UNDERCUT TO HOLE

KEYWAY

HOLE

28.378 28.380 Figure 11.27.Slitting saw with sideteeth. Figure 11.29. Screw slottingcutter.

11-24 Chapter 11MILLING MACHINES AND MILLING OPERATIONS has fine teeth cut on its circumference. It is made in various thicknesses to correspond to American Standard gage wire numbers. ANGLE CUTTER.Angle cutters are used to mill surfaces that are not at a right angle to cutter axis. You can use angle cutters for a variety of work, such as milling V-grooves and dovetail ways. On work such as dovetailing, where you cannot mount a cutter in the usual manner on an arbor, you can mount an angle cutter that has a threaded hole or is constructed like a shell end mill .on the end of a stub or shell end mill arbor. When you select an angle cutter for a job you should specify type, hand, outside diameter, thickness, hold size, and angle.

There are two types of angle cutters: single 28.382 and double. The single angle cutter, shown in Figure 11.31. Double angle cutter. figure 11-30, has teeth cut at an oblique angle with one side at an angle of 90° to the cutter axis and the other usually at 45°, 50°, or 80°. of the teeth well rounded. It is generally used to mill flutes in reamers. Fluting cutters are marked The double angle cutter (fig. 11-31) has two with the range of diameters they are designed to cutting faces, which are at an angle to the cutter mill. axis. When both faces are at the same angle to the axis, you obtain the cutter you want by END MILL CUTTERS.End milling cutters specifying the included angle. When they are may be the SOLID TYPE with the teeth and the different angles, you specify the angle of each shank as an integral part (fig. 11-32). They also side with respect to the plane of intersection. may be the SHELL TYPE (fig,. 11-33) in which the cutter body and thelhank or arbor are FLUTING CUTTER.A fluting cutter is a separate. End milling cuttersl ,ave teeth on the double angle form tooth cutter with the points circumference and on the end. Those on the circumference may be straight or helical.

Except for the shell type, all end mills have either a straight shank or a tapered shank which is mounted into the spindle of the machine for driving the cutter. There are various types of adapters for securing end mills to the machine spindle.

End millinginvolvesthemachining of surfaces(horizontal,vertical,angular,or irregular) with end milling cutters. Common operations include the milling of slots, keyways, pockets, shoulders, and flat surfaces, and the profiling of narrow surfaces. (See fig. 11-34.)

28.381 End milling cutters are used most often on Figure 11-30.Single angle cutter. vertical milling machines. However, they also are

11-25 34 It j MACHINERY REPAIRMAN 3 &2

as\

(A) Two-flutesingle-end; (B) Two flute double-end; Carbide-tipped, straight flutes; (H) Carbide-tipped,RH (C)Three -flute single-end; (D) Multiple-flute sinale-end; helical flutes; (I) Multiple-flute with (E) Four-flute double-end; (F) Two-flute taper shank; (.1) ball-end; (G) Carbide-tipped with taper shank and helicalflutes.

28.383 Figure 11-32.End mill cutters. used frequently on machines with horizontal carbide teeth or theymay be of the solid carbide spindles. Many different types of endmilling type. cutters are available in sizes ranging from1/64 Inchto2 inches. They may be made of TWO-FLUTE END MILLS haveonly two high-speed steel, or theymay have cemented teeth on the circumference.The end teeth can cut to the cutter. Hence, theymay be used to feed into the work likea drill; they can then be fed lengthwise to forma slot. These mills may be either the single end typewith cutter on one LCHAMFERED end only, or theymay be the double-end type. (See fig. 11 -32.) ROUNDRO UND ceULTIPLE-FLUTE SQUARE END MILLS have three, frsix, or eight flutes andnormally are available in diametersup to 2 inches. They may be single- or double-end (fig.11-32). 28.384 BALL END MILLS (fig. 11-3 2) Flgure 11-33.Shell End MIII (National are used for Twin Drill). milling fillets or slots witha radius bottom, for

11-26 3 1 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

STANDARD MILLING CUTTERS AND END MILLS

LENGTH OF OVERALL

LENGTH OF CUT

END CUTTING EDGE CONCAVITY ANGLE RADIAL RAKE ANGLE -4 TOOTH FACE (POSITIVE SHOWN)

END CLEARANCE TOOTH FACE

AXIAL /RADIAL RELIEF ANGLE C TYING EDGE

END GASH FLUTE

His,/ ANGLE

ENLARGED SECTION OF END MILL

RADIAL RELIEF ANGLE RADIAL CLEARANCE ANGLE

RADIAL LAND

ENLARGED SECTION OF END MILL TOOTH

28.385 Figure 11-34.End mill terms.

11-27 3 15 MACHINERY REPAIRMAN3 & 2 rounding pockets and thebottom of holes, and for all-round die sinkingand die making work. Two-flute end mills with endcutting lips can be used to drill the initialhole as well as to feed longitudinally. Four-fluting ballend mills with center cutting lips alsoare available. These work well for tracer milling,fillet milling and die sinking.

SHELL END MILLS (fig.11-33) have a hole for mounting the cutteron a short (stub) arbor. The center of the shellis recessed for thescrew or nut which fastens the cutter to thearbor. The teeth are usually helical.These mills are made in larger sizes than solid endmills. Normally, they are available in diameters from 1 1/4to 6 inches. Cutters of this typeare intended for slabbingor surfacing cuts, either facemilling or end milling.

FACE MILLING CUTTER.Insertedtooth face milling cutters (fig.11-35) are similar to 28.387 shell end mills in that theyhave teeth on the Figure 11-36.T-slot cutter. circumferenceand ontheend. They are attached directly to the spindle nose and use space" of T-slots.T-slotsare inserted teeth made of carbideor an alloy steel. cut in two The teeth are replaceable. operations. First, you cuta slot with an end mill or a plain milling cutter, and thenyou make the cut at the bottom of theslot with a T-slot T-SLOT CUTTER.TheT-slot cutter (fig. cutter. 11-36) is a smallplain milling cutterwith a thank. It is designedespecially to mill the "head WOODRUFF KEYSEATCUTTER.A Woodruff keyseat cutter(fig. 11-37) is used to

28.386 Figure 11-35.Inserted tooth facemiming cutter. 28.388 Figure 11-37.Woodruff keyseatcutter. 316 11-28 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

cut curved keyseats. A cutter less than 1 1/2 inchesindiameter has a thank. When the diameter is greater than 1 1/2 inches, the cutter is usually mounted on an arbor. The larger cutters have staggered teeth to improve the cutting action.

GEAR CUTTERS.There are several types _ of gear cutters, such as bevel, spur, involute, etc. Figure 11-38 shows an involute gear cutter. You must select the correct type of cutter to cut a III 7 particular type of gear.

CONCAVE AND CONVEX CUTTERS.A concave cutter (fig.11-39) is used to mill a convex surface, and a convex cutter (fig. 11-40) is used to mill a concave surface. 28.390 Figure 1149.Concave cutter.

CORNER ROUNDING CUTTER.Corner rounding cutters (fig. 11-41) are formed cutters that are used to round corners up to one-quarter of a circle. SPROCKET WHEEL CUTTER.The sprocket wheel cutter (fig. 11-42) isa formed cutter that is used to mill teethon sprocket wheels.

GEAR HOB.The gear hob (fig. 11-43) isa formed milling cutter with teeth cut like threads on a screw. IL_

28.389 28.391 Figure 11-38.Involute gear cutter. Figure 11-40.Convex cutter. 11-29 3/ 7' MACHINERY REPAIRMAN 3 & 2

28394 Figure 11-43.Gear hob.

28.392 Figure 11-41.Corner rounding cutter. types of cutters and theiruses, consult the Machinery's Handbook, machinistpublications, or the applicable technical manual. We willnow FLY CUTTER.The flycutter (fig. 11-44) discuss the selection of cutters. is often manufactured locally. Itis a single-point cutting tool similar in shape toa lathe or shaper tool. It is held and rotated bya fly cutter arbor. Selection You can grind this cutter toalmost any form you desire. There will be times whenyou need a Each cutter can doone kind of job better special formed cutter fora very limited number than any other cutter in of cutting or boring operations. a given situation. A cutter may or may not be limited toa specific milling operation. In selecting themost suitable Wehave discussed a number of themore cutter for a particular milling operation, common types of milling machine cutters. For you a must consider the kind of cut to bemade, more detailed discussion of these and other material to be cut, number ofparts to be machined, and the type of millingmachine available.

Anotherfactorthataffectsamilling operation is the number of teeth inthe cutter. If the number is too great, thespace between the teeth is so small that it prevents thefree flow of chips. The chip space should also besmooth and free .of sharp corners toprevent the chips from clogging the space. A coarse-toothcutter is more satisfactory for milling material thatproduces a continuous and curled chip. Thecoarse. teeth not only permit an easier flow ofchips and coolant but also help toeliminate chatter. A fine-tooth cutter is more satisfactoryfor milling a thin material. It reduces cutter and workpiece vibration and the tendency forthe cutter teeth to "straddle" the work and digin.

28.393 Another factor you shouldconsider in Figure 11-42.Sprocket wheel cutter. selecting a cutter is the diameter ofthe cutter.

11-30 318 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

FLY CUTTER

28.395 Figure 11-44.Fly cutter arbor and fly cutten.

Select the smallest diameter of the cutter that AMOUNT OF TRAVEL USING A LARGE DIAMETER CUTTER will allow the arbor to pass over the work LARGE DIAMETER AMOUNT OF TRAVEL USING A without interference when the cut is taken. As CUTTER illustrated in figure 11-45, a small cutter requires SMALL DIAMETER CUTTE less time than a larger cutter to take a cut.

ARBORS DIRECTION

You can mount milling machine cutters on WORK several types of holding devices. You must know 53-464 the devices and the purpose of each of them to make the most suitable tooling setup for the SMALL DIAMETER CUTTER operation you are performing. We will cover the various types of arbors and the mounting and 28.396 dismountingofarborsinthissection. Figure 11-45.Cutter diameter selection. MACHINERY REPAIRMAN 3 & 2 NOTE: Technically, an arbor is a shaft on which Standard arbors are available instyles A and a cutter is mounted. For convenience, since B, as shown in figure 11-46. there are so few types of cutter holders Style A arbors have that are a pilot type bearing usually11/32 inch in not arbors, we will refer to all typesof cutter diameter. Style B arbors have holding devices as arbors. a sleeve type outboard bearing. Numerals identifythe outside diameter of the bearing sleeves,as follows: STANDARD ARBOR.Thereareseveral types of milling machine arbors. Youuse the Sleeve Number common or standard types (fig. 11-46) to hold Outside Diameter and drive cutters that have mounting holes. One 3 1 7/8 inches end of the arbor usually hasa standard milling machine spindle taper of 3 1/2 inches per foot. 4 2 1/8 inches The largest diameter of thetaper is identified by a number. For example, the large diameter of 5 2 3/4 inches a number 40 milling machine spindletaper is 1 3/4 inches. The numbersrepresenting common The inside diameter milling machine spindle tapers and can be any one of several their sizes are standard diameters thatare used for the arbor as follows: shaft. Style A arbors sometimes havea sleeve bearing that permits the arborto be used as Number Large Diameter either a style Aor a style B arbor. A code system, consisting of numerals and 10 5/8 inch a letter, identifies the size and style ofthe arbor. The 20 7/8 inch code number is stamped into theflange or on the tapered portion of thearbor. The first 30 1 1/4 inches number of the code identifies thediameter of the taper. The second (and ifused, the third 40 1 3/4 inches number) indicates the diameterof the arbor shaft. The letter indicates thetype of bearing. 50 2 3/4 inches The numbers following theletter indicate the usable length of the arbor shaft. 60 4 1/4 inches Sometimes an additional number is used to indicatethe size of

PILOT BEARING

STYLE A SLEEVE TYPE BEARING

STYLE B

28.3(17 Figure 1146.Standard millingmachine arbors.

11-32 32 Chapter 11MILLING MACHINES AND MILLING OPERATIONS sleeve type bearings. The meaning of a typical code number 5-1 1/4-A-184 is as follows:

5 = taper number-50 (the 0 is omitted in the code)

1 1/4 = shaft diameter-1 1/4 inches

A = Style A bearingpilot type Figure 1147.Stub arbor. 18 = usable shaft lengthIR :riches shape and held in the arbor by a locknut, are 4 = bearing size-2 1/8 inches diameter shown in figure 11-43. Fly cutter arbor thanks may have a standard milling machine spindle STUB ARBOR.Arbors that have very short taper, a Brown and Sharpe taper, or a Morse shafts, such as the one shown in figure 11-47, taper. are called stub arbors. Stub arbors are used when it is impractical to use a longer arbor. . SCREW SLOTTING CUTTER ARBOR.Screw slotting cutter arbors are used You will use arbor spacing collars of various with screw slotting cutters. The flanges support lengths to position and secure the cutter on the the cutter and prevent the cutter from flexing. arbor. You tighten the spacers against the cutter The thanks on screw slotting cutter arbors may when you tightenthe nut on the arbor. be straight or tapered, as shown in figure 11-49. Remember, never tighten or loosen the arbor nut unless the arbor support is in place. SCREW ARBOR.Screw arbors (fig. 11-50) areused withcuttersthathave threaded SHELL END ARBOR.Shell end mill arbors mounting holes. The threads may be left- or (fig. 11-48) are used to hold and drive shell end right-hand. mills. The shell end mill is fitted over the short boss on the arbor shaft. It is driven by two keys TAPER ADAPTER.Taper adaptersare and is held against the face of the arbor by a used to hold and drive taper - sharked tools, such bolt. You use a special wrench, shown in figure as drills, drill chucks, reamers, and end nulls, by 11-47, to tighten and loosen the bolt. Shell end mill arbors are identified by a code similar to the ALINEMENT BOSS standard arbor code. The letter C indicates a shell end mill arbor. The meaning of a typical shell mill arbor code 41 1/2C-7/8 is as follows:

4 = taper code number-40 1 1/2 = diameter of mounting hole in end millI 1/2 inches C = style C arborshell end mill 7/8 = length of shaft-7/8 inch

FLY CUTTER ARBOR.Fly cutter arbors are used to hold single-point cutters. These 28.398 cutters, which can be ground to any desired Figura 1148.Shell and mill arbor.

11-33 32 / MACHINERY REPAIRMAN 3& 2

FOR DRAWIN ROD 111. \--i

TAPER SHANK

Figure 11-49.Screw slotting cutter arbor. inserting them into the tapered hole in the adapter. The code for a taper adapter indicates the number representing the standardmilling 28.399 machine spindle taper and the number andseries Figure 11-51.Taper adapter. of the internal taper. For example,the taper adapter code number 43Mmeans: locking feature. Thecam lock adapter code 4 = taper identification number-40 indicates the number of the externaltaper, number of the internal taper (whichis usually a 3M = internal tapernumber 3 Morse standard milling machine spindletaper also), and the distance that the adapterextends from the spindle of the machine. Forexample, 50-20- [f a letter is not included in the codenumber, 3 5/8 inches means: he taper is understood to bea Brown and Sharpe. For example 57 means: 50 = taper identification number(external)

20 = taper identification number(internal) 5 = taper number-50 3 5/8 = distance adapter extendsfrom spindle 7 = internal tapernumber 7B and S is 3 5/8 inches nd 50-10 means: CUTTER ADAPTER.Cutteradapters, such as shown in figure 11-52,are similar to taper 50 = taper identification number

10 = internal tapernumber 10B and S LOCK SCREW

Figure 11-51 shows a typical taper adapter. ome cutter adapters are designed to be used rith tools that have taper snanks anda cam

ALLEN WRENCH

Figure 11-60.Screw arbor. 28A00 Figure 11-52.Cutter adapter.

11-34 322 Chapter 11MILLING MACHINES AND MILLING OPERATIONS adapters except that they always have straight, 5.Stand near the column at a poilmt where rather than tapered holes. They are used to hold you can reach both ends of the milling machine. straight shank drills, end mills, etc. The cutting Align the arbor keyseats with the keys in the tool is secured in the adapter by a setscrew. The spindle. code number indicates the number of the taper 6.Insert the tapered shank of the arbor and the diameter of the hole. For example, into the spindle. 50.5/8 means that the adapter has a number 50 7.Hold the arbor in place with one hand taper and a 5/8-inch-diameter hole. and screw the drawbolt into the arbor with your other hand. NOTE: Turnthe drawbolt a SPRING COLLET CHUCK.Spring collet sufficient number of turns to ensure that the chucks (fig. 11-53) are used to hold and dive drawbolt extends into the arbor shank a distance straight-shanked tools. The spring collet chuck approxithately equal to the major diameter of consists of a collet adapter, spring collets, and a the threads being used. This will help to prevent cup nut. Spring colletsarcsimilar to lathe stripping the threads on the drawbolt or in the collets. The cup forces the collet into the mating arbor shank when the jamnut is tightened. taper, causing the collet to close on the straight 8.Hold the arbor in position by pulling shank of the tool. The collets are available in back on the drawbolt and tighten the jamnut by several fractional sizes. hand. 9.Tighten the jamnut with one wrench Mounting and Dismounting Arbors whileusing a second wrench to keep the drawbolt from turning.

Mountinganddismountingarborsare To DISMOUNT an arbor, use the following relatively easy tasks. Take care not to drop the procedure: arbor on the milling machine table or floor. Use figure 11-6 as a guide. To MOUNT an arbor, use. 1.Place the spindle in the lowest speed. :ae following procedure: 2. Turn off the motor. 3.Loosen the jamnut approximately two 1.Place the spindle in the lowest speed. turns. 2.Disengage the spindle clutch lever. 4.Use one wrench to turn the jamnut and 3.Turn off the motor switch. another wrench to keep the drawbolt from 4.Clean the spindle hole and the arbor turning. thoroughly to ensure accurate alignment of the 5.Hold the arbor with one hand and gently arbor inside the spindle. tap the end of the drawbolt with a lead mallet until you feel the arbor break free. 6. Hold the arbor in place with one hand and unscrew the drawbolt with your other hand. SPRING COLLET ADAPTER 7. Remove the arbor from the spindle. LOCK NUT SPRING COLLET MILLING MACHINE OPERATIONS

The milling machine is one of the most versatile metalworking machines. It is capable of performing simple operations, such as milling a SPANNER WRENCH flat surface or drilling a hole, or more complex operations, such as milling helical gear teeth. It would be impractical to attempt to discuss all of 28.401 the operations that the milling machine can do. Figure 11-53.Spring collet chuck adapter. We will limit these machining operations to

11-35 3,23 MACHINERY REPAIRMAN3 & 2

plain,face, and angular milling;milling flat surfaces on cylindricalwork; slotting, parting, and milling keyseats andflutes; and drilling. reaming, andboring. Even thoughwe will discuss only themore common operations,you willfindthat by usinga combination of operations, you will be ableto produce a variety of work projects. Wewill conclude the chapter PARALLELS by discussing the millingmachine attachments A .8 and gearing andgear cutting.

PLAIN MILLING

Plain milling is theprocess of milling a flat surface in a plane parallelto the cutter axis. You get the desired size of thework by individually milling each of the flatsurfaces on the object. Plain milling cutters,such as the ones shown in Figure 11-54.Machining figure11-21, are used for plainmilling.If sequence to square a block. possible, select a cutterthat is slightly wider than the width of surfaceto be milled. Make the work setup beforeyou mount the cutter. This 5. Mount the arbor in the spindle. precautionwill keep you fromaccidentally striking the cutter and 6. Clean and positionthe spacing collars cutting your handsas you and place them set up the work. Youcan mount the work in a on the arbor in such away that the cutter is above thework. vise or fixture, or clampit directly to the milling machine table. Youcan use the same methods 7. Wipe off the millingcutter end any that you used to holdwork in a shaper to hold additional spacing collars work in a milling machine. that may be n3eded. Clamp the workas Then place the cutter,the spacers, and thearbor close as possible to themilling machine column bearing on the arbor, so that you can mount the with the cutter keyseat cutter near the aligned over the key.Locate the bearingas close column. The closeryou place the cutter and as possible to the cutter.Make sure that the work to the column, themore rigid the setup work and vise will clearall parts of the machine. will be. 8. Installthe arbor nut andtightenit fmgertight only. The following stepsexplain how to machine a rectangular work blank (forexample, a spacer 9. Position theoverarm and mount the for an engine test stand). arbor support. 10. After supportingthe arbor, tighten the 1. Mount the viseon the table and position arbor nut with a wrench. the vise jaws parallel to the table length. NOTE: 11. Set the spindle The graduationson the vise are accurate enough directional control lever to give the required directionof cutter rotation. because we are concernedonly with machininga surface in a horizontal plane. 12. Determine the requiredspeed and feed, 2. Place the work in thevise, as shown in and set the spindle speedand feed controls. figure 11-54. 13. Set the feed tripdogs for the desired 3. Selectthe proper millingcutter and length of cut andcenter the work under the arbor. cutter. 4. Wipe off the tapered shank of the arbor 14. Lock the saddle. and the tapered hole inthe spindle witha clean cloth. 15. Engage the spindleclutch and pickup the cut.

11-36 394 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

16. Pick up the surface of the work by the backlash from the vertical feed before taking ioldinga long strip of paper between the the new depth of cut. To remove the backlash: otating cutter and the work; very slowly move he work toward the cutter until the paper strip 1.Lower the knee well past the original s pulled between the cutter and the work. BE depth of the roughing cut. "..1AREFUL! Keep your fingers away from the 2.Raise the knee the correct distance for :utter.Arotatingmillingcutterisvery the finishing cut. langerous. 3.Engage the feed. 17. Move the work longitudinally away from 4.Stop the spindle he cutter and set the vertical feed graduated 5.Return the worto the starting point on ;collar at ZERO. the other side of the cutter. 18. Compute the depth of the roughing cut 6.Deburr the work. 'rid raise the knee this distance. 7. Remove the work from the vise. 19. Lock the knee, and direct the coolant low on the work and outgoing side of the Place side 4 in the vise, as shown in figure :utter. 11-54D and machine the side, using the same 20. Position the cutter to within 1/16_inch procedureasforside3. When you have )f the work. using hand table feed. completed side 4, remove the work from the vise 21. Aftercompletingthecut,stop the and check it for accuracy. pindle. This completes the machining of the four 22. Return the work to its starting point on sides of the block. If the block is not too long, he other side of the cutter. you can rough and finish mill the ends to size in 23. Raise the table the distance required for the same manner in which you milled the sides. he finish cut. This is done by placing the block on end in the 24. Set the finishing speed and feed, and vise. Another method of machining the ends is :alce the finish cut. by face milling. 25. When you have completed the operation, ;top the spindle and return the work to the FACE MILLING )pposite side of the cutter. Face milling is the milling of surfaces that 26. Deburr the work and remove it from the are perpendicular to the cutter axis, as shown in rise. figure 11-55. You do.face milling to produce flat To machine the second side, place the work n the vise as shown in figure 11-54B. Rough and SHELL ENO MILL 'finish machine side 2, using the same procedures hat you used for side1. When you have WORK ,. mmpleted side 2, deburr the surface and remove he work from the vise.

Place the work in the vise, as shown in figure 11-54C with side 3 up. Then rough machine side 3. Finish machine side 3 for a short distance, VISE lisengage the spindle and feed, and return the work to the starting point, clear of the cutter. vow you cansafely measurethe distance )etween sides 2 and 3. If this distance is correct, rou can continue the cut with the same setting. T it is not, adjust the depth of cut as necessary. :f the trial finishing cut is not deep enough, raise he work slightly and take another trial cut. If 28.402 he trial cut is too deep; you will have to remove Figure 11-55.Face milling. 11-37 325 MACHINERY REPAIRMAN 3& 2 surfaces and to machine work tothe required length. In face milling, the feedcan be either COLUMN horizontal or vertical.

Cutter Setup

You can use straight shankor taper shank end mills, shell end mills,or face milling cutters for face milling. Selecta cutter that is slightly larger in diameter than thethickness of the material that you are machining.If the cutter is smaller in diameter than thethickness of the material, you will be forcedto make a series of slightly overlapping cutsto machine the entire surface. Mount the adier andcutter before you make the work setup Mountthe cutter by any means suitable for the cutteryou have selected.

Work Setup

Use any suitable means to hold the work for SOLID JAW fa( milling as lo9g/ as thecutter clears the workholding devf6e and themilling machine table. You can mount the work 28.403 on parallels, if Figura 11-56.Aligning visa jaws usingan indicator. necessary,to provide clearance betweenthe cutter and the table. Feed the workfrom the side of the cutter that willcause the cutter thrust to force the work down. If 3. Align the solid vise jawsquare with the you hold the column of the machine, usinga dial indicator for work in a vise, positionthe vise so that the accuracy. cutter thrust is toward the solidjaw. The ends of the work are usually machinedsquare to the 4. Mount the work in thevise, allowing the \\, sides of the work.Therefore, you will have to end of the work to extend slightlylieyond the align the work properly. Ifyou use a vise to hold vise jaws. the work, you can align thestationary vise jaw with a dial indicator,as shown in figure 11-56. 5. Raise the knee until thecenter of the You can also usea machinist's square and a work is approximately centeredwith the center feeler gage, as shown in figure11-57. f the cutter. 6. Lock the knee in position. Operation 7. Set the machine for theprover roughing feed, and table travel. To face mill the ends of work,such as the engine Start the spindle and pickup the end mountingblock that we discussed surface of the work by hand previously: feeding the work towarde cutter. 1. Select and mounta suitable cutter. 9. Pike a strip ofpape between the cutter and the wolic as shown in 2. Mount and positiona vise on the milling igure 11-58 to help pick up the ce. Whe the cutter picksup machine table, as shown infigure 11-55 so that the paper there the thrust of the cutter istoward the solid vise ximately .003-inch jaw. clearance between the cutterand the material being cut. 11-38326 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

COLUMN OF MACHINE

SEAM

FEELER GAGE

28.404 Figure 11-57.Aligning vise jaws using a square.

10. Once the surface is picked up, set the 13. Position the work to about 1/16 inch saddle feed graduated dial at ZERO. from the cutter, then engage the power feed. 11. Move the work away from the cutter with the table and direct the coolant flow on the 14. After completing thecut,stopthe cutter. spindle, and move the work back to the starting 12. Set the roughing depth of cut, using the point before the next cut. graduated dial, and lock the saddle. 15. Set the speed and feed for the finishing cut, and then unlock the saddle.

16. Move it in for the final depth of cut and relock it.

17. Engage the spindle and take the finish cut.

18. Stop the machine and return the work to the starting place.

19. Shut the machine off. 20. Remove the work from the vise. Handle it very carefully to keep from cutting you,rself before you can deburr the work.

21. Next, mount the work in the vise so that 28.405 the other end is ready for machining. Mill this Figure 11-58.Picking up the work surface. end in the same manner as the first, only now

11-39 32 7 MACHINERY REPAIRMAN3 & 2 you must measure the length before taking the items that are turned by finishing cut. Before removingthe work from a wrench and on drive the vise, check it for shafts and other itemsthat require a -positive accuracy and remove the drive. The following burrs from the newly finishedend. information will helpyou to understand the machiningof squares and hexagons. ANGULAR MILLING Cutter Setup Angular millingisthe milling ofa flat surface that is atan angle to the axis of the The two types ofcutters you willuse most cutter. You can usean angular milling cutter,as often to machine shown infigure11-59. However,.you can squares or hexagons are side perform angular milling and end milling cutters.You can use side milling with a plain, side,or cutters for machining work face milling cutter bypositioning the workat that is held ina the required angle. chuck and for heavycutting. You can use end mill' for work that is heldin a chuck or between centers and for light Many maintenanceor repair tasks involve cutting. If you usea side machining flat surfaces milling cutter, besure that tLe cutter diameter is on cylindrical work. large enoughso that you can machine the Thesetasksincludemillingsquares full and length of thesquare hexagons, and millingtwo fla+- in Liesame or hexagon without plane. interference from the arbor.If you use an end mill, be sure it is slightlylarger in diameter than the length of the,,square A square or hexagon ismilled on an object or hexagon The cutter to provide a positive dri thrust for both typesshould be up when the "e,n., slip area for work is mounted vertically' various tools, suchas wreAk.lies and cranks. You and down when it is will machinesquares and mountedhorizontallyinordertouse Yagons frecuently conventional (or up) milling. on the ends of bolts, taps,rearncrs, or other The reason forwhat appearstobe a Contradiction in the directionof thrust is the difference in the directionof the feed. Youcan see this by comparing figures11-60 and 11-61. HORIZONTAL SPINDLE The cutter shown in SINGLE ANGULAR figure 11-60 rotates ina CUTTER .ik counterclockwise directionand the work is fed toward the left. Thecutter shown in figure 11-61 rotates ina clockwise direction and the work is fed upward.

Work Setup DOUBLE ANGULAR CUTTER We have alreadydiscussed the methods that ANGLE PLATE you willusually useto mount the work. Regardless of theworkholding method thatyou use, you must align the indexspindle in either the vertical or horizontalplane. If youare machining work betweencenters, you must also 53.483 align the footstockcenter. If you usea screw-on DOV ETAIL chuck, take intoconsideration the cutterrotary thrust applied to thework. Always cuton the 28.406 side of the work that Figure 11-59.Angular milling. will tend to tighten the chuck on the indexhead spindle. Whenyou 11-40 328 Chapter 1 1 MILLING MACHINES AND MILLING OPERATIONS

SIDE MILLING CUTTER Oa' SQUARE ON WORK

CHUCK

DIVIDING HEAD

:tt

1, .,. 53.74

28.407 Figure 1140. Milling a augurs on work held vertically. mount work between centers, a dog rotates the are using a short end mill, to position the index work. The drive plate, shown in figure 11-62, head (fig. 11-62G) near the cutter edge of the contains two lock screws. One lock screw clamps tableto ensure that cutter and work make the Ave plate to the index center and ensures contact. thatthe drive plate moves withthe index spindle. The other lock screw clamps the tail of Calculatio. the dog against the side of the drive plate slot as shown infigureI l -62A. This eliminates any The following information will help you m -ment of the work during the machining determine the amount of material you must peratlon. Itmaybe necessary, especially if you remove to produce a square or a hexagon. The

11.41 IAJ,29 MACHINERY REPAIRMAN 3 & 2

dimensions of the largestsquare or hexagon that you can machine from a piece of stock must be calculated. The size of a square (H in fig.11-63) is measured across the flats. The largestsquare that you can cut from a given size of round stock equals the diameter of the stockin inches (which is also the diagonal of thesquare) times 0.707. This may be expressedas

Opposite side - Side of a square

Hypotenuse - Diagonal of square

45° .= 90° bisected 28.408 Figure 11.81.Milling a squareon workheld Opposite side horizontally. H - G X 0.707 or Hypotenuse- sine 45°

D-CUTTIR DIAMETER I.-LENGTH OF SQUARE

A. LOCK SCREW FOR DOO D, END MILL S. DRIVE PLATE 0, INDEX HEAD \E, TAP SQUARE C. TAP fOOTSTOCK

28.409 Figure 11-82.Milling asquare using an end mill.

11-42

, 33 0 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

The diagonal of a square equals the distance across_ the flats times 1.414. This is expressed as

Hypotenuse G = H X 1.414 or Opposite side = cosec 45°

The amount of material that you mustremove to machine each side of the square is equal to one-half the difference between the diameter of the stock and the distance across the flats.

I =G - H 2

You usethe same formula(I G- H 2 )to G determine the amount of material toremove when you are machining a hexagon. Figure 11.63. Diagram of a square. The size of the largest hexagon thatyou can machine from a given size of round stock (H in figure11-64)isequal to the diagonal (the Square or Hexagon Work diameter of the stock) of the hexagon times Mounted in a Chuck 0.866 inch, or You can machine a square or hexagonon Opposite side - Largest hexagon that can be machined work mounted in a chuck by using eithera side milling cutter or an end mill. Wo will discuss Hypotenuse- Diagonal or diameter of round stock using the side milling cutter first. Before placing side_ U - li X 0.886 orOpposite sine 60° Hypotenuse

The diagonal of a hexagon equals the distance across the flats times 1.155, or

H = G X 1.155 orHypotenuse Opposite sidecosec 60°

The length of a flat is equal to one-half the length of the diagonal, or

2

We will explain two methods of machininga square or hexagon: machining work mounted in chuck and machining work mounted between ;enters. Figure 11.84.Diagram of a hexagon.

11.43 331 MACHINERY REPAIRMAN 3 & 2

the index head on the milling machinetable, be 10. Loosen the index head spindle sure that the table and the bottom of the index lock. 11. Rotate the work one-halfrevolution head have been cleaned of all chips andother with the index crank. foreign matter. Spread a thin film ofclean 12. Tighten the index head spindlelock. machine oil over the area of the tableto which 13. Take another cut on the work. the index head will be attachedto prevent 14. When this cut is finished,stop the cutter corrosion. and return the work to the starting point. 15. Measure the distanceacross the flats to NOTE: Because most index heads are quite determine whether the cutter is removingthe heavy and awkward, you shouldget someone to same amount of metal from both sides of the help you place the head on the millingmachine work. If not, checkyour calculations and the table. setup for a possible mistake. 16. If the work measuresas it should, loosen After the index head is mountedon the the index head spindle lock androtate the work table, position the head spindle in thevertical one-quarter revolution, tighten the lock, and position, as shown in figure 11-60.Use the take another cut. degree graduations on the swivel block. This is 17. Return the work to thestarting point accurate enough for most work requiring theuse again. of the index head. The verticalposition also 18. Loosen the spindle lock. means that the work will feed horizontally. 19. Rotate the work one-half revolution.. 20. Take the fourth cut. Then, tighten the work in the chuckto keep 21. Return the work again it from turning due to the cutter thrust. to the starting Install point and set the machine for finishingspeed the arbor, cutter, and arborsupport. The cutter and feed. should be as close as practical to the column, 22. Now, finish machine oppositesides (1 Remember, this is doneso that the setup will be and3),usingthe same procedures already more rigid. Set the machine for the correct mentioned. roughing speed and feed. 23. Check the distance Machine the surface using the following across these sides. If it is correct, finish machine thetwo remaining steps: sides. 24. Deburrthe work and checkitfor 1. With the cutter turning, pickup the cut accuracy. on the end of the work. 2. Move the work sidewaysto clear the NOTE: You can also machine cutter. a square or hexagon with the index headspindle in the 3. Raise the knee a distance equalto the horizontal position, as shown in length of the flat surfaces to be cut. figures 11-61 and 11-62. If you use the horizontalsetup, you 4. Move the table toward therevolving must feed the work vertically. cutter and pick up the side of the work.Use a piece of paper in thesame manner as discussed earlier in this chapter. Square or Hexagon Work 5. Setthecrossfeedgraduateddialat Mounted Between Centers ZERO. 6. Move the work clear of thecutter. Remember, the cutter should rotate so that the Machining a square or hexagonon work cutting action takes placeas in "up milling." mounted between centers is done 7. Feed the table in the required in mucn the amount same manner as in holding the work ina chuck. for a roughing cuts, 8. Engage the power feed aid coolant flow. 1. Mount the index head thesame way, 9. When the cut is finished, stop thespindle only with the spindle ina horizontal position. and return the work to the starting point. The feed will be in a vertical direction.

11-44 332 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

2. Insert a center in the spindle and align it 12. Whilefeedingtheworkvertically, fith the footstock center. machine side1. Lower the work below the 3. Select and mount the desired end mill, cutter when you have completed the cut. referably one whose diameter is slightly greater 13. Loosen the index head spindle lock and han the length of the flat you are to cut, as index the work one-half revolution to machine hovm in figure 11-62. the flat opposite side 1. 4. Mount the work between centers. Make 14. Tighten theock. are that the drive dog is holding the work 15. Engage the power feed. After completing :curely. the cut, again lower the work below the cutter 5. Set the machine for roughing speed and and stop the cutter. :ed. 16. Measure the distance across the two flats 6. Pick up the side of the work and set the to check the accuracy of the cuts. If it is correct, raduated crossfeed dial at ZERO. indexthework one-quarterrevolutionto 7. Lower the work until the cutter clears machine another side. Then lower the work, ze footstock. index one-half revolution, and machine the last 8. Move the work until the end of the work side. Remember to lower the work below the clear of the cutter. cutter again. 9. Align the cutter with the end of the 17. Set the machine forfinishing speed, Fork. Use a square head and rule, as shown in feeds, and depth of cut, and finish machine all gum 11-65. NOTE: Turn the machine off the sides. efore aligning the cutter by this method. 18. Deburrthe work and checkitfor accuracy. 10. Move the table a distance equal to the ngth of the flat desired. 11. Move the saddle the distance required Machining Two Flats )r the roughing depth of cut. in One Plane

You will often machine flats on shafts to serve as seats for setscrews. One flat is simple to machine. You can machine it in anymanner with a side or end mill, as long as you can mount DIVIDING the work properly. However, machining two HEAD flats in one plane, such as the flats on the ends of a mandrel, presents a problem since the flats must align with each other. A simple method of machining the flats is to mount the work ina vise or on V-blocks in such a manner thatyou can machine both ends without moving the work once it has been secured. We will describe the method that is used when the size or shape of the work requires repositioning it in order to machine both flats. 1. Apply layout dye on both ends of the work. 2. Place the work on a pair of V-blocks,as SQUARE HEAD shown in figure 11-66. 3. Set the scriber point of the surfacegage tothecenter height of the work. Scribe 28.410 horizontal lines on both ends of the work,as Figure OILAligning duo work and cutter. illustrated in figure 11-66. 11.45 t33 / MACHINERY REPAIRMAN 3 & 2

10. Position the work so thata portion of the flat to be machined is locatednext to the cutter. Because of the shallow depth ofcut, compute the speed and feed as if the cutswere finishing cuts. 11. After starting the machine, feedthe work by hand so that thecutter contacts the side of the work on which the line isscribed. SCRIBED LINE MANDREL 12. Move the work clear of thecutter and stop the spindle. ICED LINE 13. Check to see if the greater portion ofthe 1111111141re cutter mark is above or below the layoutline. Depending on its location, rotate theindex head " I Wily spindle as required to center the markon the -40.11 layout line. 14. Once the mark is centered,take light V-BLOCK "cut and try" depth of cuts untilyou reach the 44(0-0 desired width of the flat. 15. Machine the flat to the requiredlength: illiVeISP:RFACEGAGE 16. When one end is completed,remove the work from the chuck. Turn thework end for 28A11 end and reinsert it in the chuck. Figure 1148.Layout of work. 17. Machine the second flat inthe same manner as you did the first. 18. Deburr the work and checkitfor 4. Mount the index headon the table with accuracy. its spindle in the horizontal position. 19. Check the flats tosee if they are in the 5. Again, set the surfacegage scriber point, same plane by placing a matched pair of parallels but to the centerline of the index 'leadspindle. on a surface plate and one flat on each of the 6. Insert the work in the hide:. leadchuck parallels. If the flats are in thesame plane, you with the end of the work extendedfar enough will not be able to wobble the work. to permit all required machining operations. 7. To align the surfacegage scriber point SLOTTING, PARTING, AND MILLING with the scribed horizontal line,rotate the index KEYSEATS AND FLUTES head spindle. 8. Lock the index head spindle in position. Slotting, parting, and milling keyseatsand flutes areall operations that involve cutting These flats can be milled with either an end grooves Inthe work. Thesegrooves are of mill or a side mill or a side millingcutter. various shapes, lengths, and depths,depending on the requirements of the job. Theyrange from CAUTION: Rotate the cutter ina direction flutes in a reamer toa keyseat in a shaft to the that will cause the thrust to tightenthe index partingoffofapieceofmetaltoa head chuck on the spindle whenyou use a predetermined length. screw-on type chuck.

9. Raise the knee with the surfacegage still Slotting set at center height until thecutter centerline is aligned with the scriber point.This puts the centerlines of the You can cut internalcontours, such as cutter and the work in internalgearsand alignment with each other. splinesandsix-or twelve-point sockets by slotting.Most slotting is

11.46 334 Chapter 11MILLING MACHINES AND MILLING OPERATIONS lone with a milling machine attachment calleda chuck. If the slotted portion does not extend lotting attachment, as shown in figure 11-67. through the work, you will have to machinean Iheslottingattachmentisfastened to the internal recess in the work to provide clearance nillingmachine column and driven by the for the tool runout. When it is possible, position ;pindle. This attachment changes the rotary the slotting attachment and the work in the notion of the spindle to a reciprocating motion vertical position to provide the best possible nuch like that of a shaper. You can vary the view of the cutting action of the tool. ength of the stroke within a specifiedrange. A Pointeron theslottingattachmentslide ndicates the length of the stroke. Youcan pivot Parting he head of the slotting attachment and position t at any desired angle. Graduations on the base if the slotting attachment indicate the angle at Use a metal slitting saw for sawing or parting vhich the head is positioned. The number of operations and for milling deep slots in metals trokes per minute is equal to the spindle rpm and in a variety of materials. Efficient sawing .nd is determined by the formula depends to a large extent upon the slitting saw you select. The work required of slitting saws Strokes per minute CFS X 4 varies greatly. It would not be efficient touse length of stroke the same saw to cut very deep narrow slots, part thick stock, saw thin stock, or saw Lard alloy The cuttingtools which you usewith steel. Soft metals, such as copper and babbitt, or lotting attachments are ground to any desired nonmetallic materials, such as bakelite, fiber, or hape from high-speed steel tool blanks. These plastic, require their own styles of slittingsaw. Dols are then clamped to the front of the slide Tram.. You can use any suitable means for Parting with a slitting saw leaves pieces that ioldingthework,butthe most common arereasonablysquare and that require the riethod is to hold the work in an index head removal of a minimum of stock in finishing the surface. You can cut off a number of pieces of varying lengths and with less waste of material than you could saw by hand. mACHINI COLUMN A coarse-tooth slitting saw is best ?or sawing GOADUNIONS brass and for cutting deep slots. A fine-tooth slitting saw is best for sawing thin metal, and a staggered-tooth slitting saw is best for making heavy deep cuts in steel. You should use slower feeds and speeds to saw steels to prevent cutter breakage. Use conventional milling in sawing !MUNI thick material. In sawing thin material, however, clamp the stock directly to the table anduse down milling. Then the slitting saw will tend to force the stock down on the table. Position the 110111N0 Alf ACHAINI work so that the slitting saw extends through the stock and into a table T-slot. HOTTING 1001

External Keyseat

28.412 Machining an external keyseat on a milling Figure 11.87.Slotting attachment. machine is less complicated than machining it on '? 11.47 1.1140 ;"), MACHINERY REPAIRMAN 3 & 2 a shaper. In milling, starting an external keyseat thesideof thecutteris is no problem. You simply bring tangenttothe the work in circumference of the work. With thecutter contact with a rotating cutter andstart cutting. turning very slowly and before It should not be difficult for contact is made, you to picture in insert a piece of paper between the workand the your mind how you would milla straight side of the cutter. Continue moving external keyseat with a plain milling the work cutter or an toward the cutter until thepaper begins to tear. end mil Rthe specified length ofthe keyseat When it does, lock the graduated dial exceeds at ZERO e leigth you can obtain by milling to on the saddle feed screw. Then lower the milling the desire ,depth, you can move the work in the machine knee. Use the saddle feeddial as a direction of the slot to obtain thedesired length. guide, and move the work Picturing in your mind how a distance equal to you would mill a the radius of the work plus one-halfthe width or Woodruff keyseat should be easier.The secret is the cutter. to select a cutter that has thesame diameter and thickness as the key. You use a similar method to align workwith an end mill. When you use an end mill,move the work toward the cutter while Straight External Keyseats you hold a piece of paper between the rotatingcutter and the work, as shown in figure 11-69. Afterthe paper tears, lower the work to just below the bottoth Normally, you would use a plain milling of the end mill. Thenmove the work and saddle cutter to mill a straight external keyseat.You could use a Woodruff cutteror a two-lipped end mill.

Before you can begin milling thekeyseat, you must align the axis of the work withthe midpoint of the width of thecutter. Figure 11-68 shows one method of alignment.

Suppose that you are going tocut a keyseat with a plain milling cutter. Movethe work until

r 4

28.413 Figure 11.88.Aligning cutter usinga paper strip. Figure 11.89.Aligning an end millwith the work.

11-48 Chapter 11MILLING MACHINES AND MILLING OPERATIONS a distance equal to the radius of the work plus Specificationsforthe depth of cut are the radius of the end mill. Move the workup, usually furnished. When specificationsare not using hand feed, until a piece ofpaper held available, the total depth of cut for a square between the work and the bottom of the end keyseat may be determined by the following mill begins to tear, as shown in figure 11-69B. formula and dimensions in figure 11-71. Then move the table and work away from the bottom of the end mill. Set and lock the graduated dial at ZERO on the vertical feed, and Total depth of cut (T) = d + f then feed up for the roughing cut. The cutter rpm and the longitudinal feed are computed in where the same manner as for conventional milling cutters. Because of the higher speeds and feeds d =T= depth of keyseat Involved, more heat is generated,so flood the work and cutter with coolant. f = R - -(4-) 2= height of arc When extreme accuracy is not required,you can align the work with the cutter visually, as shown in figure 11-70. Position byeye the work W = width of key as near as possible to the, midpoint of the cutter. Make the final alignment by moving the work in R = radius of shaft or out a slight amount, as needed. The cutter should be at the exact center of the work The height of arc (f) for various sizes of shafts diameter measurement of the steel rule. Youcan and keysis shown intable11-1. Keyseat use this method with both plain milling cutters dimensions for rounded end and rectangular and end mills. keysarecontainedintheMachinery's Handbook. Check keyseats foraccuracy with Before you begin to machine the keyseat, rules, outside and depth micrometers, vernier you should measure the width of the cut. You calipers, and go-no-go gages. Use table 11-1 for cannot be certain that the width will be the same as the thickness of the cutter, The cutter may not run exactly true on the arbor or the arbor may not run exactly trueon the spindle. The recommended practice is to nick the end of the work with the cutter and then measure the width of the cut.

28.414 Figure 11-71.Keyseat dimensions for straightsquare Figure 11.70. Visual alignment of a cutter. key.

11-49 MACHINERY REPAIRMAN 3 & 2

Table 11-1.Values for Factor If) for Venous Sizes of Shafts

WIDTH OF KEY IN INCHES

DIAMETER OF SHAFT 1/16 3/32 1/8 5/32 3/16 7/32 1/4 5/16 (INCHESI

SHAFT SIZE FACTOR (1)

1/2 . 002 . 004 . 008 . 013 . 018 025 , 033

5/8 . 001 . 003 . 006 . 010 . 014 . 019 . 025 . 042

3/4 . 001 . 003 . 005 . 008 . 0:2 . 016 . 022 034

7/8 . 001 . 002 . 004 . 007 . 010 .014 . 018 . 028

. 001 . 002 .004 . 006 . 009 . 012 . 015 . 024

1 1/8 . 002 . 003 . 005 . 008 . 011 . 014 . 022

1 1/4 . 002 . 003 . 005 . 007 . 010 . 013 . 019

1 1/2 . 001 . 002 004 006 .008 011 016

1 3/4 . 001 . 002I. 003 005 . 007 . 009 . 014

both square and Woodruff keyseats, whichwill the work with m cutter andmeasure the width be explained next. of :AA! eAactly the same manneras for milli;, .,liai keyseats, , Woodruff Keyseat A 'W 4 .r.C> wat cutter (fig. 11-72) has deep `:ici cylindrical surface of A Woodruff key is a small half-disk of metal. the teeth, The cct ,nis Glichtly thicker at the The rounded portion of the key fits inthe slot crest af the teeth t is at the center. This in the shaft. The upper portion fitsinto a slot in feature provides ciemce between the sides of a mating part, such as a pulley or gear. You align the siJt and the c:ter. Cutters with a 2-inch

1-50 3,1s Chapter 11MILLING MACHINES ANDMILLING OPERATIONS

28.415 Figure 11-72.--Woodruff keyseat cutter.

diameter and larger have a hole in the center for depth of cut are not available,use the following arbor mounting. On smaller cuttersthe cutter formula to determine the correct value: and the shank are one piece. Notethat the shank is "necked in" back of the cutting headto give Total depth (T) = d + f additionalclearance.Also, notethatlarge cutters usually have staggered teeth to improve where the cutting action. d (depth of the keyseat)= H -- As discussedearlier,to mill a Woodruff keyseat in a shaft, youuse a cutter that has the H = total height of the key same diameter than thickness as the key. Cutting a Woodruff keyseat is relatively simple. You W = width of the key simply move the workup into the cutter until you obtain the desired keyseat depth. The work The most accurate way to check thedepth may be held in a vise, chuck, between centers, of a Woodruff keyseat is toinsert a Woodruff or key of the correct size in the keyseat. clamped to the milling machine table.The cutter Measure Is held on an arbor, or in overthekey and work withanoutside a spring collet or drill micrometer to obtain the distance M chuck that has been mounted in thespindle of in figure the milling machine, as in figure 11-73. 11-74. Measure the correct micrometerreading over the shaft and key by using the formula In milling the keyseat, centrallylocate the cutter over the position in which the keyseat is M=D+(W)f to be cut and parallel with the axis of the work. T27 Raise the work by using the hand verticalfeed where until the revolving cutter tearsa piece of paper held between the teeth of thecutter and the M = micrometer reading work. At this point, set the graduated dialon the vertical feed at ZERO and set theclamp on D = diameter of shaft the table. With the graduated dialas a guide, W = width of key raise the work by hand until the full depthof the keyseat is cut. If specificationsfor the total f = height of arc

11-51 333 MACHINERY REPAIRMAN. 3 & 2

--..

No I A

28.418 Figure 11-73.Milling a Woodruffkeyseat.

H

28.417 Figure 11-74.Dimensions for Woodruffkeyseat. 3,0 11 -52 Chapter 11MILLING MACHINES ANDMILLING OPERATIONS NOTE: Tables in some references may differ thefluteisnormallyone-fourththe slightly from the above calculation for the tap value diameter. The minimum length cf the fulldepth M, due to greater allowance for clearanceat the of the flute should be equal to the length top of the key. of the threaded portion of the tap. Table 11.2 liststhe width of the cutter and the depth of the Straight Flutes flutes for taps of various diameters. Youusually The flutes on cutting tools mount the tap blank between centers and feed it serve three longitudinally past the cutter. Forappearance purposes. They form the cutting edge for th sake, the flutes are usually cut in thesame plane tool,providechannelsforreceivingand as the sides of the square on the tap blank. discharging chips, and let coolant reachthe You can mill the fluteson a tap blank in the cutting edges. The shape of the fluteand tooth Ifollowing manner: depends upon the cutteryou use to machine the flute. Thefollowinginformationpertains 1. Mount and align the index centers. specifically to taps andreamers. Since flutes are actually special purposegrooves, you can apply 2. Set the surface gage to center height. much of the information to grooves in general. 3. Place the tap blank between thecenters with one flat of the squareon the tap shank in a Tap Flutes vertical position. 4. Align the flat witha square head and You usually use aconvex cutter to machine blade. tapflutes.This type of cutter producesa "hooked" flute as shown in figure11-75. The 5. Scribe a line on the tap shank. number of flutes is determined by the diameter 6. Remove the tap blank, place of the tap. Taps 1/4 inch a dog on to1 3/4 inches in the shank, and remount the blankbetween diameter usually have four flutes, andtaps 1 7/8 centers. inches (and larger) in diameter usuallyhave six flutes. The width of the convex cutter shouldbe 7. Align the scribed line with thepoint of equal to one-half the tap diameter. Thedepth of the surface gage scriber. 8. Make sure that the surfacegage is still at center height. CONVEX CUTTER CUTTER WIDTH 1/2 TAP DIAMETER 9. Mount the convex cutter. 10. Make sure that the directionof the cutter rotation is correct for conventional(or up) milling and that the thrust istoward the index head. 11. Align the center of thecutter with the axis of the tap blank. 12. Pick up the surface of the tap. 13. Set the table trip dogs for thecorrect length of cut. HOOKED FLUTE DEPTH OF FLUTE 1/6 TAP DIAMETER 14. Set the machine for roughing speedand feed. 28.418 15. Rough mill all flutes to within0.015 to Figure 11-78.Hooked tap flutes. 0.020 inch of the correct depth.

11-53 .q z1 MACHINERY REPAIRMAN 3 &2

Table 11-2.Tap Flute Dimensions

Diameter of tap Width of cutter Depth of flute (inches) (inches) (inches)

1/8 1/16 1/32 1/4 '1/8 1/16 1/2 1/4 1/8 3/4 3/C 3/16 1 1/2 1/4 1 1/4 5/8 5/16 1 1/2 3/4 3/8 1 3/4 7/8 7/16 2^ 1 1/2 2 1/4 1 1/8 9/16 2 1/2 1 1/4 5/8 2 3/4 1 3/4 11/16 3 1 1/2 3/4

16. Set the machine for finishingspeed and negative rake to help prevent chatter. feed and finish machine all flutesto the correct To obtain size. the negative rake, positionthe work and cutter slightly ahead of thereamer center, as shown in figure 11-76. 17. Remove the work, deburr, andcheck it for accuracy. Table 11.4 lists the recommendedoffseor reamers of various sizes. Str utes are usually unequally spac d to helpprevent Reamer Flutes chatter. To obtain theun qual spacing, index the required amountasach flute is cut. The recommended variati is approximately 2°. Machinists' publicatis, such as the Machinery's Flutes may bemilled on reamers with Handbook, cont: angular fluting cutters, but charts that list the number you normally use of holes to advanor retard the index crank to special formed fluting cutters. Theadvantage: of machine a given mber of flutes when you the formed flute comparedto the flute mil use a given hole circl .You normally mill theflutes with an angular cutterare that the chips are in pairs. After yo more readily removed and the cutting tooth have machined one flute, is dex the work onalf revolution and mill the stronger. Also, the tooth is less likelyto crack or opsite flute. warp during heat treatment. Formedreamer Th epth o fluting cutters have a 6° angle e flute is determined by trial on one side and a and error. = approximate depth of flute to radius on the other side. Thesize of the radius obtainthe recommended width oflandis depends upon the size of thecutter. Reamer one-eighth the diameter for fluting cutters are manufactured an eight-fluted in eight sizes. reamer, one-sixth the diameter fora six-fluted The size of the cutter is identifiedby a number reamer, etc. (1 through 8). Reamers from 1/8 inchto 3 You can machine the fluteson a hand inches in diameter are fluted bythe eight sizes reamer in the following manner: of cutters. The correctcuttersforfluting reamers of various diameters are given in table 1. Mount the 11-3. You machine reamer blank between centers reamer teeth with a slight and the reamer fluting cutteron ine arbor.

11.54 342 Chapter 11-MILLING MACHINES AND MILLINGOPERATIONS

Table 11.3. Reamer Fluting cutter Numbers

Ramer diem- Number of Cutter number eter (inches) reamer flutes

1 1/8 to 3/16 6 2 1/4 to 5/16 6 3 3/8 to 7/16 6 4 1/2 to 11/16 6to 8 5 3/4 to 1 8 6 11/16 to 1 1/2 10 7 19/16 to 2 1/8 12 8 21/4 to 3 14 ---

2. Align the point of the cutter with the 5. Rotatethe cutter until a tooth is in the reamer blank axis and just touch the surface of verticalposition. the reamer with the rotating cutter. 6. Shut off the machine. 3. Removethework blank. 7. Move the table until the point of the 4. Then raise the table a distance equal to footstock center is aligned with the tooth that is the depth of the flute phis one-half the grinding in the vertical position. allowance. & Place an edge of a 3-inch rule against the 6° surface of thereamer tooth. Move the saddle FORMED SEAMEN untilthe edge of the3-inchrulethatis CUTTER contacting the cutter tooth is aligned with the point of the footstock center. ARSON

Table 114.Required Offset

Size of reamer Offset of cutter (inches) (inches)

1/4 0.011 3/8 0.Q16 1/2 0.022 -AMOUNT OF OFFSET 5/8 0.027 3/4 0.033 7/8 0.038 1 0.044 11/4 0.055 ISAMU 11/2 0.066 13/4 0.076 2 0.087 21/4 0.098 21/2 0.109 23/4 0.120 28.419A 3 0.131 Fiore 11.78. Negative rake tooth.

11-55 MACHINERY REPAIRMAN 3 & 2

9. To eliminate backlash, move the saddle 14. Rough machine all flutes. in the same direction it will be moved whenyou offset the cutter. Continue feeding the saddle NOTE: Write down the exact indexing until you get the desired amount of offset; then which you used for each of the flutes to avoid lock it in position. confusion when you index for the finish cut. 10. Move the table until the cutter clearsthe end of the reamer blank. 11. Remount the blank between thecenters. Fly Cutting 12. Calculate the indexing required tospace the flutes unequally. You will use a fly cutter when a formed 13. Set the table feed trip dogs so that the cutter is required but is not available. Fly cutters minimum length of the full depth of flute is are high-speed steel tool blanks that have been equal to the length of the reamer teeth. ground to the required shape. Any shapecan be

'fat

s

uvT !"'

.4;1,77 7'4 Kee e '1 ,1!

xllty x 1111.1.1.6

28.419 Figure 11-77.Offset boring head and boring tools.

11-56 Chapter 11MILLING MACHINES AND MILLINGOPERATIONS

ground on the tool if the cutting edgesare given position the boring cutter to bore holes of a sufficient amount of clearance. Fly cutters are varying diameters.This adjustment is more mounted in fly cutter arbors, suchas the one convenient than adjusting the cutterin the shown in figure 11-44. Use a slow feed anda boring bar holder or by changing boring bars. shallow depth of cut to prevent breaking the tool. It is a good idea to rough outas much Although the boring bars are thesame on a excess material as possible with ordinary cutters milling machine as on a lathe or drillpress, the and to use the fly cutter to finish shaping the manner in which they are held is different. Note surface. in figure 11-78 that a boring bar holder isnot used. The boring bar is inserted intoan adapter, and the adapter is fastened in the hole in the DRILLING, REAMING, AND BORING adjustable slide. Power for driving the boring bar is transmitted directly through the shank. The elimination of the boring bar holder results ina Drilling, reaming, and boringare operations more rigid boring operation, but the size of the that you can do very efficientlyon a milling hole that can be bored ismore limited than in machine. The graduated feed screws make it boring on a lathe or drill press. possible to accurately locate the work in relation Fly cutton, which we discussed previously, to the cutting tool. In each operation the cutting can also be for boring, as shown in figure tool is held and rotated by the spindle, and the !1-78. A fly cutter is especially useful for boring work is fed into the cutting tool., relatively shallow holes. The cutting tool must be adjusted for each depth of cut. Drilling and Reaming The speeds and feedsyou should use in boring on a milling machineare comparable to You use the same drills and reamers thatyou those you would use in boring ona lathe or drill use for drilling and reaming in the lathe and drill press and depend upon the samefactors: press. Drills and reamers are held in the spindle hardness of the metal, kind of metal in the by the same methods that youuse to hold cutting tool, and depth of cut. Because the straight and taper-shanked end mills. The work boring bar is a single-point cutting tool, the may be held in a vise, clamped to the table, held diameter of the arc through which the tool in fixtures or between centers, and in index head chucks, as is done for milling. The speeds used for drilling and reaming are determined in the same manner as for drilling and reaming in the lathe or drill press. The work is fed into the drill FL CUTTER WORK or reamer either by hand or power feed. If the AYRBOR cutting tool is held in a horizontal position, the FLY transverse or saddle feed is used. When the drill CUTTER or reamer is held in a vertical position, as ina BORED HOLE vertical ty: c. machine, you use the vertical feed. elf210&- Boring ADAPTER Of the three operations, the onlyone that warrantsspecialtreatmentisboring. On a milling machine you usually bore holes withan offset boring head. Figure 11-77 shows several IA views of an offset boring head and several boring tools. Note that the chuck jaws, which gripthe boring bar, can be adjusted at a right angle to 28.420 the spindle axis. This feature letsyou accurately Figure 11-78.Boring with a fly cutter.

11-57 MACHINERY REPAIRMAN 3 & 2 moves is also a factor. For all of thesereasons, position in both the vertical and horizontal you must guard against operating at too greata planes. These attachments will enable speed or vibration will occur. you to do more easily jobs which would otherwise bevery complex.

MILLING MACHINE ATTACHMENTS HIGH-SPEED UNIVERSAL ATTACHMENT Many attachments have been developed which increase the number of jobsa milling machine can do or which make such jobseasier By using a high-speed universal attachment, to do. you can perform milling operations at higher speeds than those for which the machinewas designed. This attachment is clamped VERTICAL MILLING ATTACHMENT to the machine and is driven by the millingmachine spindle, as you can see in figure 11-80. Youcan swivel the attachment spindle head For instance, by using and cutter a vertical milling 360° in both planes. Theattachment spindle is attachment (fig.' )) you can convert the driven at a higher speed thanthe machine horizontal spindle a vertical spindle machine spindle. You must consider the ratiobetween and swivel the cutter toany position in the the rpm of the two spindles when verticalplane. By using a universal milling you calculate cutter speed. Small cutters, end mills, anddrills attachment, you can swivel thecuter to any should be driven at a highrate of speed to maintain an efficient cutting action.

DEGREE GRADUATIONS

DEGREE GRADUATIONS

28.421 28.422 Figure 11-79.Vertical milling attachment. Figure 11-80.High-speed universal millingattachment.

11-58 Chapter 11MILLING MACHINES AND MILLINGOPERATIONS

DEGREE GRADUATIONS ROTARY TABLE DRIVE SHAFT

r

HAND WHEEL END GEARING HOUSING

28A23 Figure 11.81. Circular milling attachment withpower feed.

CIRCULAR MILLING ATTACHMENT used tospacethe rackteeth quickly and accurately. This attachment (fig.11-81) is a circular table that is mounted on the milling machine RIGHT-ANGLE PLATE table.Thecircumferenceof thetableis graduated in degrees. Smaller attachmentsare The right-angle plate (fig. 11-83) is attached usually equipped for hand feed only, and larger tothetable. Theright-angleslotpermits ones are equipped for both hand and power mounting the index head so that the axis of the feed. This attachment may be used formilling head is parallel to the milling machine spindle. circles, arcs,segments,circular T-slots, and With this attachment you can make worksetups internal and external gears. Itmay also be used which are off center or ata right angle to the for irregular form milling. table T-slots. The standard size plateT-slots make it convenient to change fromone setting to another for milling a surface ata right angle. RACK MILLING ATTACHMENT

RAISING BLOCK The rack milling attachment, shown in figure 11-82, is used primarily for cutting teethon racks,althoughitcan be usedfor other Raising blocks (fig. 11-84) are heavy-duty operations. The cutter is mounted ona spindle parallels which usuallycome in matched pairs: that extends through the attachment parallelto They are moDrited on the table, and theindex the table T-slots. An indexing arrangement is headismountedontheblocks.This

11-59 34 MACHINERY REPAIRMAN 3 & 2

-t.

4

, AL' t

J. 1' 1

1 4.14 IL SPINDLE 1r,fi

CUTTER

FEED

WORK HOLDING FIXT E

28.424 Figure 11-82.Rack milling attachment.

Figure 11-83.Right-angle plate. Figure 11.84.Raising blocks.

11-60 Chapter 11MILLING MACHINES AND MILLINGOPERATIONS

arrangement raises the index head and makes it SPEEDS possible to swing the head througha greater range to mill larger work. Heat generated by friction between the cutter and the work may be regulated by theuse of proper speed, feed, and cutting coolant. TOOLMAKER'S KNEE Regulationofthisheatisvery important because the cutter will be dulledor even made useless by overheating. It is almost impossibleto The toolmaker's knee (fig. 11-85) isa simple set down any fixed rules that will govern cutting but useful attachment for settingup angular speeds because of varying conditions from jobto work, not only for milling but also for shaper, job. Generally speaking,you should select a drill press, and grinder operations. Youmount a cutting speed that will give the best compromise toolmaker's knee, whichmay have either a between maximum production and longest life stationary or rotatable base, to the table of the of thecutter.Inany particular operation, milling machine. The base of the rotatabletype consider the following factors in determining the is graduated in degrees. This feature enablesyou proper cutting speed. to machine compound angles. The toolmaker's knee has a tilting surface with eithera built-in Hardness of the Material Being Cut: The protractor head graduated in degrees for setting harder and tougher the metal beingcut, the the table or a vernier scale formore accurate slower should be the cutting speed. settings. Depth of Cut and Desired Finish: The amount of friction heat produced is directly FEEDS, SPEEDS, AND COOLANTS proportional to the amount of material being removed. Finishing cuts, therefore, oftenmay be made at a speed 40% to 80% higher than that Milling machines usuallyhave a spindle used in roughing. speed range from 25 to 2,000rpm and a feed range from 1/4 inch to 30 inches per minute Cutter Material: High-speed steel cutters (ipm). The feed is independent of the spindle may be operated from 50% to 100% faster than speed; thus, a workpiececan be fed at any rate carbon steelcutters because high-speed steel available in the feed range regardless ofthe cutters have better heat resistant properties than spindle speed being used. Some of thefactors carbon steel cutters. concerning the selection of appropriate feeds and speeds for milling are discussed inthe Type of Cutter Teeth. Cutters that have following paragraphs. undercut teeth cut more freely than thosethat havearadialface;therfore,cutters with undercut teeth may run at higher speeds.

TILTING SURFACE Sharpness of the Cutter: A sharp cutter T- SLOTS may be run at much higher speed than a dull cutter.

Use of Coolant: Sufficient coolantwill usually cool the cutter so thatitwill not BASE GRADUATIONS GRADUATIONS overheat even at relatively high speeds. The approximate values given in table 11-5 may be used as a guide when you are selecting 28.425 the proper cutting speed. Ifyou find that the Figure 11-85.Toolmaker's knees. machine, the cutter, or the work cannot be 11-61 34 9 MACHINERY REPAIRMAN 3 & 2

suitably operated at the suggested speed,make Table 11 immediate readjustment. --Surface Cutting Speeds Byreferringtotable11-6,youcan determine the cutter revolutionsper minute for cutters varying in diameter from 1/4 inch to 5 Carbon steel High Speed cutters (ft. steel cutters inches. For example: You are cutting witha per min. ) 7/16-inch cutter. If a surface speed of 160 feet (ft. per min.) per minute is required, the cutter revolutios per minute will be 1,398. RoughFinishRoughFinish If the cutter diameteryou are using is now shownintable11-6, determine the proper Cast iron: revolutions per minute of the cutter by the Malleable 60 75 90 100 formula: Hard castings 10 12 15 20 Cutting speed X 12 Annealed tool. (a) rPm 3.1416 X Diameter steel 25 35 40 50 Low carbon steel 40 50 60 70 or fpm rpm =0.2618 XD Brass 75 95 110 150 Aluminum 460 550 700 900 where

rpm = revolutions per minute of the cutter 28.280A

fpm = required surface speed in feedper minute EXAMPLE: What is the cutting speed ofa 2 1/4-inch end mill running at 204 rpm? D = diameter of cutter in inches fpm = 0.2618 X D X rpm 0.2618 = constant = 12 rpm = 0.2618 X 2.25 X 204

EXAMPLE: What is the spindle speed fora fpm = 120.1 1/2-inch cutter running at 45 fpm? FEEDS 45 rpm0.2618 X 0.5

rpm = 343.7 The rate of feed is the rate of speedat which the workpiecetravelspastthecut. When To determine cutting speed when spindle selecting the feed, you shouldconsider the speed and cutter diameterare known, use the following factors. following formula:

fpm X 12 = rpm X 3.1416 X D Forces are exerted against the work, the cutter, and their holding devices during the fpm =3.1416 X Diameter X rpm cutting process. The forceexerted, varying 12 directly with the amount of metalremoved, can be regulated by the feed and depthof cut. The feed anti depth of cut, therefore, fpm = 0.2618 X D Xrpm seem to be interrelated, and in turn, are dependentupon

11-62 Table 11.6.-Cutter Speeds in Revolutions Per Minute

Surface speed (ft. per min.)

Diameter

of cutter 25 30 35 40 50 55 60 70 75 80 90 100 ), 140 160 180 200 (in.) ro

Cutter revolutions per mint

1/4 382 458 535 611 764 851 917 1 070 1,147 1 222 11376 1 528 1 834 2,1392,4452,7503,056

06306 367 428 489 611 672 733 856 917 978 1,100 1 222 1 466 1,7111,9552,2002,444 r

3/8 255 306 357 408 509 560 611 713 764 815 916 1 018 1,222 1,4251,6291,8322,036

7/16218 262 306 349 437 481 524 611 656 699 786 874 1,049 12241,3981,5731,748

1/2 191 229 268 306 382 420 459 535 573 611 688 764 917 1 0701,2221,3751,528 () 5/8 153 184 214 245 306 337 367 428 459 489 552 612 736 857 9791 1021,224 z 3/4 127 153 178 203 254 279 306 357 381 408 458 508 610 711 813 9111,016

7/8 109 131 153 175 219 241 262 306 329 349 392 438 526 613 701 788 876

1 95.5115 134 153 191 210 229 267 287 306 344 382 458 535 611 688 764

1 1/4 76.391.8107 123 153 168 183 214 230 245 274 306 367 428 490 551 612

1 1/2 63.776.389.2102 127 140 153 178 191 204 230 254 305 356 406 457 508

13/4 54.565.576.487 3109 120 131 153 164 175 196 218 262 305 349 392 436 z

2 47.857.366.976.495.5105 115 134 143 153 172 191 229 267 306 344 382 0 2 1/2 38.245.853.561.276.384.291.7 107 114 122 138 153 184 213 245 275 306

3 31.838.244.6 51 63.769.976.4 89.1 95.3 102 114 127 152 178 208 228 254

3 1/2 27.332.738.244.654.560 65.5 76.4 81.8 87.4 98.1 109 131 153 174 196 20 7.1

4 0 23.928.733.438.247.852.657.3 66.9 71.7 76.4 86 95.6 115 134 153 172 191

5 19.122.926.730.638.242 45.9 53.5 57.3 61.1 68.8 76.4 91.7 107 122 138 153

28.281 351. 3 5 2 MACHINERY REPAIRMAN 3 & 2

the rigidity and power of the machine.Machines inch. The formula for calculating chip load is: are limited by the power they can developto turn the cutter and by the amount of vibration Chip load feed rate (ipm) they can withstand whencoarse feeds and deep cutter speed (rpm) X number cuts are being used. of teeth in cutter Table11-7provides recommended chip loads for milling various materials withvarious The feed and depth of cut also depend types of cutters. uponthetype of cutter being used.For example, deep cuts or coarse feeds shouldnot be attempted with a small diameter end mill;such COOLANTS an attempt would spring or break the cutter. Coarse cutters with strong cuttingteeth can be fed at a relatively high rate of feedbecause the The purpose of a cutting coolant is to reduce chips will be washed out easily by thecutting frictional heat and thereby extend the life of the lubricant. cutter's edge. Coolant also lubricates thecutter face and flushes away the chips, reducing the possibility of damage to the finish. Coarse feeds and deep cuts should not be used on afrailpiece of work or on work Ifa commercial cutting coolant is not mounted in such a way that the holdingdevice available, you can make a good substituteby will spring or bend. thoroughly mixing 1 ounce of sal sodaand 1 quart of lard oil in l gallon of water. Sincethe coolant tank holds 4 or The desired degree of finish affectsthe gallons, increase the amount of feed. When a fast feed is used, metal ingredientsproportionall This emulsion is is removed rapidly and the finishwill not be suitable for machining most metals. very smooth. However, a slow feed rate anda In machining aluminum,you should use high cutter speed will producea fine f finish. For kerosene as a cutting coolant. Machinecast iron roughing, it is advisable touse acoMparatively dry, although you can usea blast of compressed low speed and a coarse feed. More mistakesare air to cool the work and thecutter. If you use made by overspeeding thecutter than by compressed air, be extremely carefulto prevent overfeeding the work. Overspeedingmay be possible injury to personnel andmachinery. detected by a squeaking, scrapingsound. If chattering occurs in the milling machineduring When using a periphery millingcutter, apply thecutting process,reducethe speed and the coolant to the point at whichthe tooth increase the feed. Excessivecutter clearance, leaves the work. This will allowthe tooth to poorlysupportedwork,or a badly worn cool before you begin the nextcut. Allow the machinegeararealso common causes of coolant to follow freelyon the work and cutter. chattering.

One procedure for selecting appropriate feed HORIZONTAL BORING MILL for a milling operation is to consider the chip load of each cutter tooth. The chip load is the thickness of the chip that a single toothremoves The horizontal boring mill is usedfor many from the work as it passes over the surface. For kinds of shopwork, suchas facing, boring, example, with a cutter turning at 60 rpm, having drilling, and milling. In horizontalboring mill 12 cutting teeth, and a feed rate of 1 ipm, the work, the setup of the work,as well as the chip load of a single tooth of the cutter will be setting of the tools, is similarto that found in 0.0014 inch. A cutter speed increase to 120rpm lathe and milling machine. work;therefore, a reduces the chip load to 0.0007 inch;a feed detailed discussion of these operationswill not increase to 2 ipm increases chip load to 0.0028 be necessary in this section.

11-64

3-74../ kip Chapter 11-MILLING MACHINES AND MILLING OPERATIONS

Table 11-7.-Recommended Chip Loads

Face Helical Sloting ° End Form Material Relieved Circular Mills Mills Side MallJ Mills Saws Cutters

Plastic .013 .010 .008 .007 .004 .003 Magnesium and alloys .022 .018 .013 .011 .007 .005 Aluminum and alloys .022 .018 .01? .011 .007 .005 Free cutting brasses & bronzes .022 .018 .013 .011 .007 .005 Medium brasses & bronzes .01.4 .011 .008 .007 .004 .003 Hard brasses & bronzes .009 .007 .006 .005 .003 .002 Copper .013 .010 .007 .006 .004 .003 Cast iron, soft (150- 180 BH)* .016 .013 .009 .008 .005 .004 Cast iron, med. (180- 220 BH) .013 .010 .007 .007 .004 .003 Cast iron, hard (220 - -300 BH) .011 .008 .006 .006 .003 .003 Malleable iron .012 .010 .007 .006 .004 .003 Cast steel .012 .010 .007 .006 .004 .003 Low carbea steel, free mach .012 .010 .007 .006 .004 .003 Low carbon steel ... .010 .008 .006 .005 .003 .003 Medium carbon steel .010 .008 .006 .005 .003 .003 Alloy steel, annealed (180-220 BH) .008 .007 .005 .004 .003 .0C2 Alloy steel, tough (220-300 BH).... .006 .005 .004 .003 .002 .002 Alloy steel, hard (300-400 BH) .004 .003 .003 .002 .002 .001 Stainless steel, free mach. .010 .e^ .006 .005 .003 .002 Stainless steels .... .006 .005 .004 .003 .002 .002 Monel metals .008 .007 .005 .004 '.003 .002

*(BH: Brinell Hardness Number)

28.282

Thehorizontalboringmill(fig.11-86) machined the height of the column for full consists of four major elements: vertical travel of the head. BASE AND COLUMN: The base contains all HEAD: The head contains the horizontal thedrive mechanisms for the machine and spindle, auxiliary spindle, and the mechanism '''provides a platform which has precision ways for controllingit. The head also provides a mlichined lengthwise for the saddle. The column station for mounting various attachments. The provides support for the head and has two rails spindle feed and spindle hand feed controls are

11-65 354 -u

H k;

SPINDLE 4' SPINDLE a CLAMP HEAD FEED LEVER i' I ANDWHEEL CLAMP , BACKREST LEVER BLOC( il FEED AND 1

, RAPID BACKREST 'FEED SPINDLE TRAVERSE ( CHANGE LEVER LEVERS 1. ,I, i I TABLE

BED

SADDLE

SADDLE FEED TABLE FEED DIRECTIONAL HEAD FEE( DIRECTIONAL LEVER DIRECTIONAL LEVER LEVER

31;7u J

28.426 Figure 11-86.Horizontalboring mill. Chapter 11MILLING MACHINES AND MILLING OPERATIONS contained in the head, along with the quick shims should all be fastened securely.If a traverse turnstile and spindle feed engagement workpiece is not properly secured, thereis lever. always the possibility of ruining the material or the machine and the risk of causing injury to the SADDLE AND TABLE: A large rectangular machine shop personnel. slotted table is mounted on a saddle which can be traversed the length of the ways. The T-slots Different jobs to be done on the boring mill are machined the entire length of the table for may require different types of attachments. holding down work and vafiot::: attachments, Such attachments include angular milling heads, such as rotary table angle plates, etc. combination boring and facing heads, thread leadarrangements,etc.Boringheadsare BACKREST OR END SUPPORT: The available in a variety of diameters. These'boring backrest is mounted on the back end of the heads prove particularly useful in boring large ways. It is used to support arbors and boring diameter holes and facing large castings. Locally bars as they rotate and travel lengthwise through made collars may be used also. Stub arbors are the work, such as in-line boring of a pump casing used to increase desired diameters. or large bearing. The Lack rest blocks have an antifriction bearing which the boring bar passes COMBINATION BORING through and rotates within. The back rest blocks AND FACING HEAD travel vertically in unison with the head. The two types of horizontal boring mill The boring and facing head (fig. 11-87) is usually found in Navy machine shops and shore used for facing and boring large diameters. This repair activities are the table type, used for small work, and the floor type, used for large work. The floor type is the most common of the two types found in shops. You will find this machine well-suited for repair work where machining of large, irregular jobs is commonplace. The reference to size of horizontal boring mills differs with the manufacturer. Some use spindle size. For example, Giddings and Lewis model300Thasa3-inchspindle.Other manufacturers refer to the largest size boring bar the machine will accept. In planning a job both of these factors should be considered along with the table size and the height that the spindle can be raised. Always refer to the technical manual for your machine. Setting up the work correctlyismost important. Failure to set the work up propPfiy can prove costly in man-hours and material. Oftentimes you will find that it is not advisable to set up a casting to a rough surface and that it will be preferable to set it up to the layout lines, since these lines will always be used as reference. It is important that holding clamps used to secure a piece of work be tight. If braces are used, they should be placed in such a manner 126.32X that they cannot come loose. Blocks, stops, and Figure 11-37.Combination boring and facing head.

11-67 35 MACHINERY REPAIRMAN 3 & 2

attachment is mounted and bolted directlyto 7.After you have tightened the the spindle sleeve and has mounting a slide with automatic bolts,rotatethe feed adjusting armon the feed which holds the boringor facing tools. backing plate untilthe arm points directly attactirieEt can be fed automaticallyor toward the front. positionedmanually.) Althoughthereare 8.Mount the restraining blockon the head. various SLIM each is made and used similarly. 9.Set the slide manually by inserting The heads are balanced the to permit high-speed tee-handled wrench into the slotin the slide operation with the tool slide centered. When adjusting dial and turning the wrench until using tools off center, you must be careful the to slideispositioned. The dialis graduated in counterbalance the heed. oruseitat lower thousandths of an inch with speeds. one complete turn equaling a 0,125-Inch movement of theslide. Generally, the boring and facinghead will come equipped with smveraltoolholders for Aftertheslideis clamped inplace, a single point tools, right anglearm, boring bar, spring-loaded safety clutch preventsmovement and boons bar holder whichmounts on the of the slide or damage to the feedmechanism if slide the feed is inadvertently engaged. Youmust remember that this is not providedto allow To set up and operate the boringand facing continuous operation of the head when head the slide is clamped and the feed is engaged.Itis a jammingprotectiononly. A distinctand I Retrut the spindle of the machine into continuous ratcheting of the safety clutchwarns the sleeve. higage the spindleram clamp lever. you to unlock the slide or disengage the feed. Do thorniest the overrunning spindle feed not confuse this warning with the intermittent clutch to prevent inadvertent engagement of the ratcheting of the feed driving clutchesas the spindle power feed while the combination head head rotates. The same safey clutch stops the ismounted onthemachine. (Iftheslide feed at the end of travel is cantered and locked, the spindle the slide, thus may be run preventing jamming of the slid&or mechanism through it for use In other operationswithout through overtravel. removingtheattachment,butthespindle overrunning clutch should be disengaged again The slide directional lever Is located before use of the slide Is resumed), on the backing plate beneath the feedadjusting arm. 3,Set the spindle for the speed to be used. The arrows on the face of theselector indicate 4 Before shifting the spindle back-gear to which way it should be turned forfeeding the neutral or making any spindle back-gear change slide in either direction. Thereare also two when the combination head Is mounted on the positions of the selector for disengagingthe slide sleeve. rotate the sleeve by jogging it until the feed. The direction of the spindlerotation has heavy end of the head is down, Thisis a safety no effect on the direction of the slide feed, precaution to prevent injury to theoperator or damage to the work. Any spindleback-par The slide feed rate adjusting change requires a momentary shift arm scale is to neutral, graduated in 0,010-inch incrementsfrom 0.000 allowing Ira. turning of the sleeve. The sleeve to0,050inch,exceptthatthefirsttwo may then unexpectedly mow until the heavy end of the facing head increments are each 0,005 inch. Set the feedrate is down contacting the by turning the knurled adjustingarm to the of eretorOfthe work, desired feed in thousandthsper revolution. S Linthe head into positionon the nwhine at the sleeve by inserting an eyebolt When mounting the single pointtoolholders, into the tapped hole in the periphery ofthe be sure the tool point is heed on center or slightly below center so the cuttingedge has proper tu low up the bolt holes inthe sleeve clearanceatthe with those small diameters. The feed inthe head, jug the spindle into mechanism may be damaged position if the head is operated with the tool abovecenter.

11.68 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

After you mount the facing head, perform BORING MILL OPERATIONS the machining operation using the instructions found in the operator's manual for your boring You should be able to perform drilling, machine. reaming, and boring operations. In addition, you may be required to use a boring mill to face RIGHT ANGLE MILLING ATTACHMENT valve flanges, bore split bearings, and bore pump cylindrical liners.

Therightanglemillingattachmentis Drilling, Reaming, and Boring mounted over the spindle sleeve and is bolted directly to the face of the head. It is driven by a Drillingandreamingoperationsare drive dog inserted between the attachment and performed in the horizontal boring mill in the the spindle sleeve. This attachment lets you same manner in which they are performed in a perform milling operations at any angle setting radial drill. The only major difference in the two through a full 3600. You can perform boring setups is in the way the tools are held in the operations atright angles to the spindle axis machines. In the horizontal boring mill the tool using either the head or the table feed depending is held in the horizontal position (fig.I1 -89) and onthepositionof the hole to be bored. in the radial drill the tool is held in the vertical Standard milling machine tooling may be used ii, position. thespindle,being heldinbyadrawbolt extending through the spindle. A right angle In Line Boring milling attachment is shown in figure 11-88. To set the horizontal boring machine for a line boring operation, insert a boring bar into the spindle and pass it through the work. The boring bar is supported on the foot end by the back rest assembly. Depending on the size4Q the bore required. you can use either standaror locally manufactured tooling. The head provides the rotary motion for the tools mounted in the boring bar. Align the work with the axis of the boring bar, and bolt and/or clamp it to the table. The cutting operation is usually performed by having the spindle move relative to the work, which is held stationary. The machine is also designed to hold the bar in a fixed position and move thetablelengthwise to complete the operation. (See fig. 11 -90.) The table can be power driven to provide travel perpendicular to the spindle, making it possible to bore, elongated and slotted when used in conjunction with vertical movement of the head. Some boring mills have a single spindle in the head while others have a secondary or auxiliary spindle which can be fitted with a precisionheadandusedinsomeboring operations. This secondary spindle may also be 120.33X used on light work such as drilling incurately Figure 11.8q. Angular milling head. spaced small holes.

11.69

3.5,Q MACHINERY REPAIRMAN 3 & 2

is1400ermoda.4

126.30X Figure 11-89.Drilling in the horizontal boring mill.

ReconditiOning wiped, it must be reconditioned at the first Split-Sleeve Bearings opportunity. If it has wiped only slightly, itcan probably be scraped to a good bearing surface Practically all of the high-speed bearings the and restored to service. If badly wiped, it will Navy uses on turbines are the babbitt-lined have to be rebabbitted and rebored,or possibly split-sleeve type. Once a bearing of this type has replaced.

Figure 11.90. Boring bar driven by the spindleand supported In the backrest block.

11-70 35,9 Chapter 11MILLING MACHINES AND MILLING OPERATIONS

When a wiped bearing is sent to the machine Distribution of oil is brought about by the shop for repair the following procedure should oil grooves. These grooves may be of several be followed as closely as possible. forms; the two simplest are the axial and the circumferentialgrooves.Sometimescircum- 1.Check for extent of damage and wear ferential grooves are placed at the ends of the marks. bearings as a controlling device for preventing 2.Take photos of bearing to indicate actual side leakage, but this type of grooving does not condition of bearing and for future reference in affect the distribution of lubricant. machining steps and assembly. When grooves are machined into a bearing, 3.Check shell halves for markings. A letter you must be careful in beveling the groove out or number should be on each half for proper into the bearing leads to prevent the oil from identification and assembly. (If not marked, you constricting. The type of. grooves used ina should do so before disassembly.) bearing should not be changed from the original 4.Inspect outer shell for burrs, worn ends design, unless warranted by continuous trouble and condition of alignment pins and holes. traceableto improper lubricantdistribution 5.Check blueprint and job order to ensure within the bearing. information required is available to you. Uponcompletionof all machining 6.Ensure that actual shaft size has not operations, itis the responsibility of both the been modified from blueprint. repair activity and the ship's force to determine thatthe bearingisin accordance with the Whenyoumustrelineandrebore blueprint specifications and that a good bond babbitt-lined bearings, remove allof the old exists between the shell and the babbitt metal. lining by machining down to the base metal of theshell. Then clean the bearing shell with Threading special cleaning solutions and rebabbitt them after plugging all oil holes with suitable material. Threads may be cut using the horizontal After relining the shell, remove the excess boring mill on machines that are equipped with babbitt extending above the horizontal flanges a thread lead arrangement. On some machines, a by rough machining on a shaper. Take extreme thread lead arrangement with as many as 23 care to see that the base metal of the horizontal different threads, both standard and metric, is flangesis not damaged during this machining available. operation.After rough machining, bluethe 1 cut threads with these machines, use a remaining excess babbitt and scrape it until no system of change gear combinations to obtain moreexcessbabbittextendsabovethe the different leads. Secure a single point tool in horizontal flanges. a suitable toolholder and mount the toolholder Next, assemble the two half-shells and set in the spindle of the machine. While you cut them up on the horizontal boring mill. Check threads, keep the spindle locked in place. The the spherical diameter of the bearing to ensure saddle, carrying the workpiece, advances at a thatitisnotdistortedbeyondblueprint ratedeterminedby thechangegear specificationsin accordancwith NAVSHIPS combination. Feeding, in conjunction with the 9411.8.13.2.Generally,thewords "BORE spindle rotation in the low back gear range, TRUE TO THIS SURFACE" are inscribed on produces the threads. the front face of the bearing shell. When dialing Cut the thread a little at a time in successive in the bearing, be sure to dial in on this surface;. passes. The thread profile depends on how the Once the bearing is properly aligned in the cuttingtool isground.Whenyouhave boring mill, you can complete practically all the completed the first pass, back the cutting tool other operations without changing the setup. off a few thousandths of an inchto avoid Bore the bearing to the finished diameter and touchingtheworkpieceonthereturn machinetheoilgroovesasperblueprint movement. Then reversethespindledriving specifications. motor.This causesthe saddle directionto

11-71 3V0 MACHINERY REPAIRMAN 3& 2

reversewhilethedirectionselectionlever position remains unchanged. 9. To disengage the feed,place the thread Allow the machine lead driving gear lever in standard to run in this direciton until thecutting tool has position. The returned to its starting point. dutch will disengage. Do NOTdo :his Advance the cutter lurint_ to take out a littlemore stock, and after setting the threading operationor the thread the spindle motorto run in forward, make 1-ad timing will be lost. another cutting pass. Follow thisprocedure until the thread is completed. Aboring bar with a microadjustable tool bitor a small precision MILLING MACHINE head is ideal for thisoperation. It allows fast, SAFETY PRECAUTIONS easy adjustment of the tool depth, plusaccuracy and control of the depthsetting. To set up for cutting threads, Yourfirst considerationas a Machinery remove the Repairman thread lead accesscovers and set up the correct shouldbeyourownsafety. geartrain combination CARELESSNESS and IGNORANCE arethe two as prescribed by the great manufacturer's technical manual. menacestopersonalsafety.Milling After the gear machinesare train has been set up, lock the slidingarm by not playthings and must be accordedthefullrespect tightening the nuts on thearm clamp. BO'sure to thatisdue any replace the retaining washers machine tool. Foryour own safety observe the on all the studs and following precautions: lock them with thescrews provided with the machine. Refer to themanufacturer's technical manual for the machine NEVER attempt to operatea machine you are.itsingfor correct gem arrangement. unless you are sure thatyou understand it thoroughly. Some of the gear combinationsuse only one gear on the B stud. When thisoccurs, take up Do NOT throwanoperatinglever the additional spaceon the stud by adding without knowing in advancewhat is going to spacers to the stud. The followingcheck-off list take place. will be of assistanceto you in threading ina horizontal boring mill: Do NOT play with the controllevers or idly turn the handles ofa milling machine, even I.Be sure the correct changegears are on if it is stopped. the proper centers. NEVER lean against 2.Position the head back-gearin the low or rest your hands range. upon a moving table. If it isnecessary to touch a moving part, know in advancethe direction in 3.Place the feed change leverin the correct which it is moving. position to release the standardfeed. Do NOT take a cut without 4.Engage the thread leadengaging lever. making sure that the work is held securelyin the vise or 5.Shift the drivinggear lever to the thread fixture and that the holdingmember is rigidly lead position. fastened to the machine table. 6.Start the spindle rotationforward. Always remove chips witha brush or 7.Place the saddle directionallever in the other s citable tool; NEVERuse fingers or hands. left position. It will remainin this position until the thread is completed. Before attempting to operateany milling machine,studyitthoroughly. Thenifan 8.Placethe feed/rapid traverseselector ever in the feed position. This will h emergency arises, you can stopthe machine ': in the immediately. Knowing howto stop a machine is 'cadclutchuntilthecompletethreading >peration is completed. Just as important, ifnot more important,as knowing how to start it.

11.72 fi.1 Chapter 1IMILLING MACHINES AND MILLING OPERATIONS

You must above all KEEP CLEAR OF practices you are likely to findit dangerous. THE CUTTERS. Do NOT touch a cutter, even There is always the danger of getting caught in when it is stationary, unless there is good reason the cutter. Never attempt to remove chips with to do so, and then be very careful. the fingers at the point of contact of cutter and work. There is danger to the eyes from flying chips, and you should always protect your eyes The milling machine is not dangerous to with goggles and keep your eyes out of line of operate, but if you do not follow certain safety the cutting action.

11-73tity,; 'hoe, CHAPTER 12

SHAPERS, PLANERS, AND ENGRAVERS

In this chapter we shall discuss the major geared shaper the ram is move,. by a spur gear typesof shapers,planers,and which meshes wit:i a rack secured to the bottom (engraving),theirindividualcomponents, of the ram. In a hydraulic shaper, the ram is cutters, and operating principles and procedures. moved by a hydraulic cylinder whose piston rod A shaper has a reciprocating single-edged cutting is attached to the bottom of the ram. Uniform tool which removes metal from the work as it is tool pressure, smooth drive, and smooth work fed into the tool. A planer operates on a similar are features of the hydraulic type shaper. principle except that the work reciprocates, and the tool is fed into the work. A is There arc many different makes of shapers, used primarily for machine engraving letters and but the essential parts and controls are the same designs on any type of material. A pantograph on all. When you learn how to operate one make can be used to engrave concave, convex, and of shaper, you should not have too much spherical surfaces as well as flat surfaces. trouble in learning to operate another make. Figure 12 -Iis an illustration of a crank shaper found in shops in some N. iy ships. SHAPERS SHAPI A 1BLIEr A shaper has a reciprocatingram thatcarries a cutting tool. The tool cuts on the forward AI() the variety of jobs you will be stroke of the ram, which is slower than the c.,AI using the shaper, you must know return stroke. The work is held in a vise or on th on III.ion and operation of the main the worktable, which moves at right angles to co ilium ii, , 'deli are the main frame assembly, the line of motion of the ram, permitting the d rsou, , crossrailassemb!y,toolhead surfacebeing cutstoprogressacrossthe a tablefeed mechanism. (See fig. machined.Shapersarc identifiedby the maximum size of a cube it can machine; this, a 12 ' 24inch shaper will machine a 24-inch cube. Main rrarne Assembly TYPES OF SHAPERS T1o. main frame asseml,ly.!,!...ists of the There are .hree distinct typesof base and the column. The base nuuses the shaper,- crank, gearet', and hydraulic. The type lubricating pump an ::ampwhichprovide depends on how the ram receives motio.. to forced lubrication to ,rw nw.iiine. The column produceits own reciprocating motion. Ina containsthe drive find feedactuating crank shaper the ram is moved 11 a rocker arm, me,dianisins. Adovetail slide is machined on top whichisdriver,by anadJustable crankpin of the column to receive the rum. Vertical flat secured to t' 0, main driving gear. Quick return of waysare machined on the front of tip! column the ,am isif 'caws,. of a crank shaper.In a to received the crossrail. MACHINERY REPAIRMANI & 2

TOOLHEAD TOOLHt AD RAM SWIVEL

CLAPPER BOX

TOOLPOST

CLAPPER ,COLUMN

VISE

WORKTABLE

TABLE SUPPORT BRACKET

CROSSRAIL APRON BASE

28.219X Figure 12-1.Standardshaper.

Drive Assembly the crank gear outward.The sliding block fits The drive assembly over the crankpin and isa free sliding fit in the consists of the ram and rocker arm. If you the crank assembly,These parts convert the center the crankpin (and therefore the slidingblock) with the axis of rotary motionofthedrivepiniontotll,. the crank gear, the rockerarm will not move when reciprocath.motion of theram. By using ti, Ldjustments the crank gear turns. Butif you set the crankpin provided,you cani, creaseof off center (by turning iecrease the length of stroke'of the ram, and the stroke adjusting Ipso positioi the ram screw), any motion of thecrank gear will cause so that the strop, g in the rocking motion of the proper area in relation to the work. rocker arm. This motion is transferred to theram through the ram linkage and starts the reciprocating You can adjust the motion of theram. CRANKPIN, which is The distance that the nounted on the crankgear, from the center of crankpin is set off center determines the length ofstroke.

12-2

3.;41 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

RAM CLAMP RAM POSITIONING OEVICE RAM RAM BLOCK RAM POSITIONING SCREW TOOLHEAO ' CLAPPER BOX

TOOLPOST

I

RAM LINKAGE

CRANK UPPER ROCKER ASSEMBLY PIVOT COLUMN CRANK GEAR WORKTABLE DRIVING PINION

CROSS RAIL CROSSRAIL APRON STROKE AOJUSTING ROCKER ARM SCREW VERTICAL WAYS TABLE LOWER ROCKER TABLE ELEVATING PIVOT SUPPORT SCREW BRACKET ';IV:117/1%,, BASE

/NW

28.220X Figure 12-2.Crosssectional view of a crank type shaper.

Topositionthewn,turntheram The worktable may be plain or universal as positioningscrewuntiltheramisplaced shown in figure 12-3. Some universal tables can properly with respectto the work. Specific be swiveled only right or left, away from the procedures for positioning the ram and setting perpendicular; others may be tilted fore or aft at the stroke are in the manufacturer's technical smallanglestothe,ram.T-slotsonthe manual for the specific machine(s). worktablesarefor mounting the work or work-holding devices. A table support bracket Crossrail Assembly (foot) holds the worktable and can be adjusted to the height required. The,bracket slides along a flat surface on the base as the table moves The crossrail assembly includes the crossrail, horizontally. The table can be adjusted vertically the crossfeed screw, the table, and the table by the table elevating screw (fig. 12-2). support bracket (foot). (Seefig.12 -I.) The crossrail slides on the vertical ways on the front Table Feed Mechanism of the shaper column. The crossrail apron (to whichtheworktableissecured)slideson Thetablefeedmechanism(fig.12-4) horizontal ways on the crossrail. The crossfeed consists of a ratchet wheel and pawl, a rocker, screw engages in a mating nut which is secured and a feed drive wheel. The feed drive wheel to the buck of thapron. The screw can be (driven by the main crank), which operates turned either manu illy or by power to move the similarly to the ram drive mechanism, converts table horizontally rotary motion to reciprocating motion. As the

12-3 MACHINERY REPAIRMAN3 & 2

the tooth as it is rockedin an opposite direction. To change the directionof feed, lift the pawl and rotate it one-halfturn. To increase the rate of feed, increase thedistance between the feed drive wheel crankpin and thecenter of the feed drive wheel.

The ratchet wheel andpawl method of feeding crank type shapershas been used for many years. Relatively late modelmachines still use similar principles. As specificprocedures for operatingfeedmechanisms may vary,you should consult manufacturers'technical manuals for explicit instructions.

Toolhead Assembly

The toolheadassemblyconsists of the toolslide, the downfeedmechanism, the clapper A box, the clapper head,and the toolpost at the forward end of theram. The entire assembly can be swiveled and set atany angle not exceeding 50° on either side ofthe vertical. The toolhead israised or lowered byhand feed to make 28.221X vertical cuts on the work. Figure 12.3. Swiveled and tiltedtable. In making verticalor angular cuts, the clapperbox must be swiveled away from the surface to bemachined (fig. feed drive wheel 12-5); otherwise, the toolwill dig into the work rotates, the crankpin (which on the return stroke. can be adjusted offcenter)causes the rocker to oscillate. The straight facefo the pawl engagesa slotinthe ratchet wheel,thus turning the SHAPER VISE ratchet wheel and the feedscrew. The back face of the pawl is angularand therefore rides over The shaper viseisa sturdy mechanism secured to the table byT-bolts. The vise hastwo jaws, one stationary,the other movable, thatcan CONTROL KNOB be drawn together bya screw. The vise differs ROCKER (OSCILLATES PAWL ON FEED SCREW) from other vises in thatthe jaws are longer and FEED DRIVE WHEEL deeper and will ATCHEI CONNECTING CRANKPIN (ADJUSTABLE open to accommodate large WHEEL LINKAGE TOWARb OR AWAY FROM work. Most such vises CENTER OF WHEEL) have hardened steel jaws FEED DRIVE ground in place. Theuniversal visemay be WHEEL swiveled in a horizontalplane from 0° to 180°. EED The usual positions :REW are either to have the jaws set parallel with the strokeof the ram or to have them at right anglesto the stroke. See that the ROCKER POSITIONING SCREW vise is free fromany obstruction which might keep the work fromseating properly. Burrs and rough edges on the 28.222 vise and chips left from previous machinings shouldbe removed before Figure 12.4. Mechanical table feedmechanism. starting to work.

12-4 1) II to1) Chapter 12SHAPERS, PLANERS, AND ENGRAVE}

DOWNFEED MECHANISM NOLODOWNS OR GRIPPERS

CLAPPER HEAD 110111111 TOOL POST CLAPPER BOX

TOOLSLIDE PARALLEL WORK POSITION FOR HORIZONTAL CUTTING

28.224X PuSIT IONS FOR DOWN CUTTING Figure 12-8.Methods of holding and clamping.

28.223 The toolholders that you will most commonly Figure 12-5.Too 'head assembly in various positions. use are:

Work can be set on parallels so that the 1.Right-hand,straight,andleft-hand surface to be cut is above the.top of the vise. toolholders (fig.12-7) which may be used for Shaper holddowns can be used in holding the the majority of common shaper and planer work between the jaws of the vise (fig. 12-6). operations. Work larger than the visewill hold, can be 2. Gangtoolholders(fig. 12-7)are clamped directlytothe top or side of the especially adapted for surfacing large castings. machine table. When work too large or awkward With this toolholder you make multiple cuts for a swivel vise must be rotated, the work can with each forward stroke of the shaper. In this be clamped to a rotary table. V-blocks, angle manner each tool takes a light cut and there is plates, and C-clamps are also used in mounting less tendency to "break out" at the end of a cut. work on shaper tables. 3.Swivel head toolholders (fig.12-7) are universal, patented holders that may 1:,.; adjusted TOOLHOLDERS to place the tool in various radial positions. This feature allows the swivel head toolholder to be convertedinto a straight,right-hand,or Various types of toolholders, made to hold left-hand holder at will. interchngeable toot bits, are used to a great 4.Spring toolholders (fig. 12.7) have a rigid extent in planer and shaper rk.Toolbits are U-shaped spring which lets the holder cap absorb available in different sizes anu are hardened avid a considerable amount of vibration. 'this holder cut to standard lengths to fit the toolholders. is particularly good for use with formed cutters

12-5 ,-14 MACHINERY REPAIRMAN3 & 2

iw

1

LEFT -HANG, STRAIGHT, ANO RIGHT -NANOTOOLHOLOERS GANG TOOLHOLOER ANO MULTIPLECHIP PROOUCEO

11111illoor.

SWIVEL HEAO TOOLHOLOER

EXTENSION TOOLHOLOER

28.225 Figure 12.7.Toolhulders.

which have a tendency to chatterand dig into good safety practices the work. are observed. You should read and understand the safetyprecautions and 5.Extensiontoolholders(fig.12-7) are adapted for cutting internal operating instructions postedon or near the keyways, splines, machine prior to operating and grooves on the shaper. The the shaper. Some extension arm of good safety practicesare listed here but are the holder can be adjusted forlength and radial position of the tool. intended only to supplementthose posted on the machine.

Procedures for grinding shaper andplaner tool bits for various operationsare discussed in 'Chapter 6 of this training manual. Always wear gogglesor face shield.

SHAPER SAITTY PRECAUTIONS Ensure that the workpiece,vise, and setup fixture is properly secured. The shaxr, ,:ke allmachines in the machine Ensure that the workarea is clear of shop, is not a dairer,us pieceof equiptneut if tools.

12.6 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

Inform other personnel in the area to and machinist's square as shown in figure 12-8. prevent possibleinjury to them from flying If either the table or the vise is off parallel, chips. checkfordirtunder the vise or improper adjustment of the table support bracket. Ensure that the travel of the ram is clear to both front and rear of the machine. Adjust the ram for length of stroke and position. The cutting tool should travel 1/8 to Never stand in front of the shaper while 1/4 inch past the edge of the work on the it is in operation. forward stroke and 3/4 to 7/8 inch behind the Avoid touching the tool, clapper box, or rear edge of the work on the return stroke. workpiece while the machine is in operation. Feeds ;;Id Speeds Never remove chips with your bare hand; always use a brush or piece of wood. The speed of the shaper is regulated by the Keep area around the machine clear of gear shift lever. A speed indicator plate shows chips to help prevent anyone from slipping and relative positions of the shift lever for a variety falling into the machine. of speeds. The change gear box, located on the operator's side of the shaper, lets you change the Remember: SAFETYFIRST, speed of the ram and cutting tool according to ACCURACY SECOND, and SPEED LAST. the length of work and hardness of the metal. When the driving gear is at a constant speed, the ram will make the same number of strokes per SHAPER OPERATIONS minute regardless of whether the stroke is 4 inches or 12 inches. Therefore, to maintain the same cutting speed, the cutting tool must make Before beginning any job on the shaper, you three times as many strokes for the 4-inch cut as should thoroughly study and understand the it does for the 12-inch cut. blueprint or drawing from which you are to work.In addition, the following precautions should be taken: Determining cutting speeds for the shaper is more difficult than determining speeds for the lathe, drill press, or milling Machine. Because the Make certainthatthe shaper iswell oiled. motion is reciprocating, you must consider the number of strokes a minute, taking into account Clean away ALL chips from previous the time ratio between the cutting stroke and work. the return stroke.In most shapers ittakes approximately 11/2 times as long to make the Be surethatthecutting toolis set cutting stroke as it does to make the return properly; otherwise the tool bit will chatter. Set stroke. This means that in any one cycle of rain the toolholder so that the tool bit does not action the cutting stroke consumes 3/5 of the extend more than about 2 inchcq below the time and the return stroke 2/5 of the time. On clapper box. this basis, we can cc Aclude that rain speed in feet per minute divided by 3/5 will give the The piece of work should be held rigidly speed of the cutting strike in feet per minute. in the vise to prevent chatter. You can seat the work by tapping it with a babbitt hammer. Theformulagivenbelow,basedon information in the preceding paragraph, can be Test the table to sec if It is level and usedfordeterminingstrokesnerminute square. Make these tests with a dial indicator necessary to produce a particular cutting speed

12-7 34'9 MACHINERYREPAIRMAN 3 & 2

INDICATE ALONG PARALLEL

TOOLPOST

SOLID JAW VISE SQUARE ADE BLOCK

I N/C:\\ T !BL 2/*10141 STOCK 1;;*

JO /NT

28.226X Figure 12-.Squaring the tableand the vise.

orfordeterminingthe cutting speed from strokes per minute: EXAMPLE: If the numberof strokes per minute is 60 and the lengthof the stroke is S inches, what is the cutting speed? CS = SPM x LOSx 0.14 SOLUTION: Where; CS = cutting speedin feet per minute SPM x LOS it 0.14= CS SPM= strokes per minute LOS= length of stroke in ink.lies 605 x 0.14 = 42 fpm 0.14= constant To find the numberof strokes per minute when the desired cutting Intheformula speed is known, simply forcuttingspeed,the transpose the formula: constant converts the cuttingtime factor froma full time basis to thecorrect fractional basis and also converts inchesto feet. SPM CS 0.14 x LOS

12-8 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

Table 12.1 goes recommended cutting speeds and an end edge are machined in the first setup. for venous Metall The opposite face and opposite end edge are Varyingratesofhorizontal feed up to machined in the second setup. The side edges are approximately0 170inchperstroke are machined in two similar but separate setups. The available on most shapers. There are no hard and vise jaws are aligned at right angles to the ram. fast rules for selecting a specific feed rate in The ram stroke and position are set as required shapingConsequently, when selecting feeds, in relation to the width of the block; howgver, you must rely on past experience and common the stroke and position must be readjusted for emu Generally. for making roughing cuts on machining the side edges. nodly held work. the feed should be as heavy as To machine aoctangular block from a the machine win allow. For feu rigid setups and rough casting, proceed as follors: for (Utilising. use light feeds and small depths of cutThe best procedureisto start with a I.Clamp the casting in the vise so that a relatively light feed and increase the feed until a face surfaceis horizontally level and slightly drivable feed rate is reached above the top of the vise jaws. Allow one end edge to extend out of the side Of the vise jaw lasepir4 a Rectangular Block enough so that a cut can be taken on the e edge without unclamping the casting. Now fe An z,i;cu...t.t:v machined rectangular block the cutting tool down to the required depth a.,d zss itf,,Knotr surfaces that are parallel to each take a horizontal cut across the face surface. oth-te. aro! the edges adjacent to any surface are After the face is machined, readjust the cutting ha*ACT talth that surface. In this discussion. face tool for down cutting and, using the downfeed vivfo:t:,, are the surtek.:. of the block having the mechanism, take a vertical cut on the end edge luitaor eta. ihr end edges are the extending out of the vise jaws. Check the end faiiror/:et Much limit the kngth of the block; and edge for squareness with the face surface and the %sir Mrs the surfaces limiting the width adjust the toolhead swivel to offset inaccuracies. ci the Nix k 2. To machine the second face surface aAld second end edge, turn the block over and set the The rectangular block can be machined in previously machined face surface on parallels tour setups when a shaper vise is used. One face (similar io the method used in step I). Insert

Takla 12.1.Resentatended Cutting Speeds for Various Metals

Cutting speed (feet per minute)

Type of metal Carbon steel tools High-speed steel tools

Roughing1Finishing Roughing Finishing

Cast iron 3o 60 40 Mild steel 25 40 50 80 Tool steel 20 30 40 60 Brass Bronze 75 100 150 200 A luta mum 75 100 150 200

2s2n.o MACHINERY REPAIRMAN3 & 2 small strips of paper betm each corner of the Shaping Keyways in Shafts block and the parallels. Thisnrovides a means of ensuring that the block isfirmly seated on the Occasionally, you may haveto cut a keyway parallels. Clamp the block inthe vise and usea in a shaft by using theshaper. Normally,you soft-face mallet to tap thi. blockdown solidly on will lay out the length the parallels. When the blockis held securely in and width of the keyway the vise and the strips of on the circumference of the shaft.A centerline paper indicate that the laid out along the length block is resting solidlyon the parallels, machine of the shaft andacross the second face surface and the end of the shaft will,make the setup easier. second end edge to As the shaper cutting the correct thickness andlength dimensions of tool cannot be used for the block. making a cut all theway to the end of the keyway, holes (of thesame diameter as the 3. To machine the sideedge, open the vise keyway width andslightly deeper than the jaws so that the jaws can be clamped on the end keyway) must bedrilledtoprovidetool edges of theblock. Now set the blockon clearance at the end of thecutting stroke. Figure parallels in the vise withthe side edge extending 12-9 shows how the holesshould be located for out of the jaws enoughto permit a cut using the cutting a blind keyway (notending at the end of downfeed mechanism. Adjustthe ram for length a shaft). If the keyway extendsto the end of the of stroke and for positionto machine the side shaft, only one hole isnecessary. edge and make thecut. To cut a keyway ina shaft, proceed as follows: 4. The other sideedgeisset up and machined as described instep 3. 1.Lay out thecenterline, the keyway width, Shaping Angular Surfaces andtheclearance holecentersas illustrated in part A offigure 12-9. Drill the clearance holes. Two methodsare used for machining angular surfaces. For steep angles,such as on V-blocks, the work;is mounted 2.Position the shaft in theshaper vise or horizontally level and the on the worktable so that it is toolhead !is swiveledto the desired angle. For parallei to the ram. Use a machinist'ssquare to check the centerline small aes of taper, such ason wedges, the work isounted on Vie tableat the desired angle frothe horizontal,or the table may be tilted if the shaper isequipped with a universal table. To machine a steepangle using the toolhead swiveled to the proper angle:

A 1.Set up the workas for machining a flat surface parallel with thetable. 2.Swivel the toolhead (seefig. 1 to the required angle. (Swivel theclapper x in the opposite direction.) \.\ ; 1.4:71vz:4- 3.Start the machine and,using the manual feed wheel on the toolhead,feed the tool down across the workpiece. Tne depth ofeach cut is regulatedbythehorizontalfeedcontrols. (Pecause the tool is fedmanually, be careful to feed the tool towardthe work only during the 28.227 return stroke.) Figure 12-9.Cutting keyway in the middle ofa shaft.

12-10 372, Chapter 12SHAPERS, PLANERS, AND ENGRAVERS on the end of the shaft to ensure that itis Shaping on Internal Keyway perpendicular to the surface of the worktable. This ensures that the keyway layout is exactly When an internal keyway is to be cut in a centered at the uppermost height of the shaft, gear, you will have to use extension tools. They thus preventing angular misalignment of the lackthe rigidity of external tools, and the sides of the keyway. cutting point will tend to spring away from the work unless you take steps to compensate for 3.Adjust the stroke and position of the this condition. The keyway MUST be in line ram, so that the forward stroke of the cutting with the axis- of the gear. Test the alignment tool ends at the center of the clearance hole. (If with a dial indicator by taking a reading across a blind keyway is being cut, ensure that the the face of the gear; swivel the vise slightly, if cutting tool has enough clearance at the end of necessary, to correct the alignment. the return stroke so that the tool will remain in The bar of the square-nose toolholder should the keyway slot.) (See B of fig. 12-9.) not extend any farther than necessary from the shank; otherwise the bar will have too much 4.Position the work'under the cutting tool "spring" and will allow the tool to be forced out so that its center is aligned with the centerline of of the cut. the keyway. (If the keyway is over 1/2 inch The extension toolholder should extend as wide, cut a slot down the center and shave each far as practicable below the clapper block, rather sideof the slotuntil the proper widthis than in the position shown by the dotted lines in obtained.) part A of figure12-10. The pressure angle resultingwith thetoolholderin the upper 5.Start the shaper and, using the toolhead position may cause the pressure of the cut to slide, feed the tool down to the depth required, open the clapper block slightly and so allow the as indicated by the graduated collar. tool to leave the cut. In the lower position, the

HINGE PIN

PRESSURE ANGLE OF TOOL IN UPPER AND LOWER POSITIONS

SHANK GEAR BAR

VISE SQUARE NOSE TOOL

A B

28.227A Figure 12-10.Internal keyway. A. Shaping internal keyway in a gear. B. Depth of keyways.

12-11 3'/3

4.> MACHINERY REPAIRMAN3 & 2 pressureangle ismore nearlyverticaland the machining operation the preventstheclapper block from opening. work may be held Another method for preventing in the vise or clamped directlyto the worktable. the clapper Aftertheworkhasbeen block from opening is tomount the tool in an mountedand inverted position. positioned, the tooth space isgenerally roughed out in the form of a plainrectangular groove with a roughing tool, thenfinished with a tool With the cutting tool setup as in part A of ground to tooth contour and figure 12-10, center the toolwith the layout size. lines in the usualmanner, and make the cut to the proper depth while The operations requiredfor machining a feeding the toolhead rack should be performedin the following down by hand. With thesetup in an inverted sequence. position, center the tool withthe layout lines at the top of the hole, andmake the cut by feeding the toolhead upward. 1. Clamp the work in the viseor to the table. The relative depthsto which external and ini,Tnal keyways are cutto produce the greatest 2. Positionasquaringtool,whichis strength, areillustrated by part B of figure narrower than the required toothspace, so that 12-10. In cutting a keywayin a shaft, the crown the tool is centered with thefirst tooth space to "X"isremovedfirst,then the downfeed be cut. micrometer collar is set to zero and the depth of 3. Set the graduated dialon the crossfeed the keyway is gaged from thiszero setting. This screw to zero, and use it as a guide forspacing of depthwillbeequaltothe distance "Z." the teeth. However, in cutting the matingkeyway in the gear, the micrometer collar is setto zero at the 4. Move the toolslide downuntil the tool point where the cuttingtool first touches the just touches the work andlock the graduated edge of the hole. The distance"Y," to which the collar on the toolslide feedscrew. keyway is cut in thegear is then made equal to the depth "Z." The total 5. Start the machine andfeed the toolslide distance of "X" plus down slightly less than the "Y" plus "Z" is equalto the height of the key whole depth of the tooth, using the graduatedcollar as a guide, and which is to lock thetwo parts together. (See fig. 12-10.) rough out the first toothspace. 6. Raise 'he tool to clearthe work and Shaping Irregular Surfaces move the crossfeed a distance equalto the linear pitch of the rack tooth byturning the crossfeed Irregular surfacescan be machined by using lever. Rough out the secondtooth space and form ground tools andby hand feeding the repeat this operation until allspaces are roughed cutting tool vertically whilepower feed moves out. the work horizontally. An example of work that 7. Replace the roughing might be shaped using formtools is a gear rack. tool with a tool ground to size for the toothform desired, and Irregularly shaped worksuch as concave and align the tool. convexsurfacescanbe shapedusingthe toolhead feed. When irregularsurfaces are being 8. Adjust the work 'so thatthe tool is in machined, close attention isrequired because proper alignment with the first toothspace that the cutting tool is controlledmanually. Also in has been rough cut. this work the job should be laid out before 9. Set the graduated dial machining to provide referencelines. Roughing on the crossfeed screw at zero and use it asa guide for spacing cuts should be taken toremove excess material the teeth. to within 1/16 inch of thelayout lines. 10. Move the toolslide You can cut RACK TEETHon a planer as down until the tool well as on a .shaper just touches the workand lock the graduated or milling machine. During collar on the too' e feed crew.

12-12 3 71 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

11. Feed the toolslide down the whole depth VERTICAL SHAPERS of the tooth, using the graduated collar as a guide, and finish the first tooth space. The vertical shaper (slotter) shown in figure 12. Raise the tool to clear the work and 12-12 is especially adapted for slotting internal move the crossfeed a distance equal to the linear holes or keyways with angles up to 10°. Angular pitchir the rack tooth by turning the crossfeed slotting is accomplished by tilting the vertical lever. in(fig.12-12B), which reciprocates up and 13. Finishthe secondt( Jth space,then down, to the required angle. The toolhead (fig. measure the thickness of the ,Jot;. vith the gear 12-12C) can be rotated to any angle. Although tooth vernier caliper. Adjust the toolslide to ditk.rent models of machines will vary in the compensate for any variation indicated by this location of the control levers, all of them will measurement. have the same basic functions and capabilities. 14. Repeattheprocess of indexing and The speed of the ram is adjustable to allow for cutting until all teeth have been finished. thevariousmaterials.andmachining requirements and is expressed in either strokes Irregular surfaces commonly machined on per minute or feet per minute, depending on the the shaper are CONVEX and CONCAVE radii. particular model. The length and the position of On one end of the work, lay out the contour of the ram stroke may also be adjusted. Automatic the finished job. When shaping to a scribed line, feed for the cross and longitudinal movements, as illustrated in figure 12-11, it is good practice and on some models the rotary movement, is to rough cut to within 1/16 inch of the line. provided by a ratchet me...thanism, gear box, or You can do this by making a series of horizontal variablespeedhydraulicsystem,again, cuts using automatic feed and removing excess depending on the model. Work may be held in a stock. Use a left-hand cutting tool to remove vise mounted on the rotarytable, clamped stock caathe right side of the work and a directly to the rotary or held by special fixtures. right-hand cutting tool to remove stock co.: the A -zalve handwheel is an example of work that left side of the work. When 1/16 inch of metal can be doni on a machine of this type. The remains above the scribed line, take a tilt and bevel the edge to the line. This will eliminate tearing the line by the breaking of the chip. Starting at the right-hand side of the work, set the automatic feed so that the horizontal travel is rather slow and, feeding the tool vIrtically by CLUTCH LEVER hand, takethefinishing cuts to produce a VERTICAL smooth contoured surface. RAM FEEDING MECHANISM

TOOLhEAD COLUMN STOCK REMOVED BY ROUGH CJTTING CUTTING TOOL ROTARY TABLE

STOCK REMOVED BY SMOOT FINISH CUTTING BASE SCRIBED TRANSVERSE LINE FEED LONGITUDINAL FEED HANDWHEEL HANDWHEEL

28.229 28.331 Figure 1211.Shaping irregular surfaces. Figure 12-12.Vertical shaper.

12-13 3 MACHINERY REPAIRMAN3 & 2

square hole in the center of thehandwheel is cut side and the top surfacesof work mountedon on a slight angle to match theangle of the the table. square on the valve stem. If this holewere cut by using a broachor an angular (square) hole drill, the square would wear prematurely due to CONSTRUCTION AND MAINTENANCE the reduced area ofcontact resulting froma straight and an angular surfacebeing mated together. All ptors consist of fiveprincipal parts: the bk 1, table, columns,crossrail, and the toolhead.

PLANERS The bedisa heavy, rigid casting which supports the enbr:,!ece of machinery. On the Planers are upper surface of are the ways upon rigidly constructed machines, which the planer table particularly suitablefor machining large and heavy work where longcuts are required. In The table isa cast surface to which general, planers and shaperscan be used fu the work is mounted. similaroperations.However,reciprocating, -Pr table has motion of planers is provided 'r-slots and reamed wcrk to by the worktable table. On the unden;Jt (platen), while the cuttingtool is caused to feed ;.1. the there is at right angles to this motion, 12.ily a gear trainor Tialw MCC. thus allowing the ?ives the table WI cut to advance like theshaper, the planer cuts r...'..procating Motion. only or. the forwardstroke, after which the 7;14,: columns ofa clouWe laou.4.;ing 1)!itniirare table is caused to makea quic* return to bring fkt:.aciff,ed to either side ofthe Led antl at one end the work into position ut: for the next cut. Planer 1.; planer. On theopen side 1:11:;ner heris size is designated by thesize of the largest work only one columnor housing attachedon one that can be clampedand machined on its table, side of the bed. Thecolumns serve to support thus a 30 inch by 30inch by 6 foot planer isone and cant' the crossrail. thatcan accommodate workup tothese dimensions. The crossrailserves as the rigid support for the toolheads. Twoadjustments on the crossrail, vertical and horizontal TYPES OF PLANERS feed screws, enablean operator to adjust for varioussize pieces of work. Planers are divided into two genera' classes, The tooihead is similar theOPENsidetypeandthel..01)LE to that of the shaper HOUSING type. it onerajon andconstruction. All slidingsurfaces subjecttc.,wear are Planers of the open type (f.g. I2 -'.3) providedwithadjustments. Keep the have a single vertical gibs, to which the adjusted to takeut, my looseness due towear. crossrailis attached. advantage of this design lies in the fact the: may b.. planed that is too wide topass between the uprights of OPERATING THE PLANER a double housing machine.

In the double housing rlfore operatinga 1. aver, be 3.. ife thatyou planer, the worktable know where the various moves between two vertical housings controls :.rt. and what to which a function each controls. crossrail and toolheadare attached. The larger Once you rave Tn, red machines are usually equipped the operation ofone model or type Natter, with two cutting you will have little caffculty in heads mounted to thecrossrail as well as a side operating others. head mounted Specific details ofop- cation, however, should on each housing. With thissetup, obtained from the it is possible to simultaneouslymachine both the manufacturer'stechnical manual for the machine:Al are using. General

12-14 () jo Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

TINTP. AL ONTO INAPT TOOLIMAII DINICTIONAL MIMS CLUTCH LATIN

CINSSINIO

CROWN& aSSINSLT

'NOMAD

CROSMIOR TMP O00 sAssui

ORT(11111 CONTROL

INICTIONAL RITIRSISIO SOL TIRO MAIM CONTROL

CIRISSNAIL IUD SOS

NORIZONT&L PUS CLUTCH Livia

livIRRN0 KM. RIMI

ON. IstSil. IMITATING SCitt MAN UNTIIOL MOO CONTROL RPM CONTROL)

START4TOP UMW seLICTOR (STOP POSITION)

28.230X Figure 1213.Open side planer. information on one type of planer is provided in within eacl. -ar is acr;omplished by means the following sections. the flow control lever. By moving the flow. control lever tr,lward the right, the table speed Table Speeds will be gradually increased until it reaches the highest pc. Able speed. The tablespeeds are controlled by the The LOW speed range is for shaping 1., 1 start-stop lever and the flow control lever (fig. materials which r' tuire high cuttir,: 'orce at low 12-13). There are two ranges of speeds provided speeds. The NIG- I range if for sLfter materials and a variation of speeds within each range. The which requireless cutting force but higher speedrange( LOW-MAXIMUM CUTor cutting speeds. HIGH-MINIMUM CUT) isselectedby the The RETURN speed control provides two start-stoplever, and the variation of speeds return speed ranges (NGAMAL aad FAST).

12-15 3 MACHINERY REPAIRMAN 3 & 2

When NORMAL is selected, the return speed Planers having a side headare provided with varies in ratio with the cutting speedselected. In FAST, the return speed remains power vertical feed and hand horizontal feed for constant (full the side head. The vertical feedis engaged or speed;, independent of the cutting speedsetting. disengaged and the direction,up or down, is selected by means of the lever Feeds on the rear of the side head feed box. Verticaltraverse of the side head is accomplished through thesquared shaft Feed at% istment is made byturning the projecting from the end of handwheelwhich controls the feed box. theamount of Horizontal movement, both feed andtraverse, is toolhead feed. Turning the handwheelclockwise by means of the bellcrankon the end of the decreases the amount of feed, whileturning the toolhead slide. handwheel counterclockwise increasesthe feed. The amount of feedcanbe read on the Rail Elevation graduated dials at the operator'send of the crossrail feed box. Each graduationindicates a The crossrail movement of 0.001 inch. israised or lowered bya handcrank on the squared shaftprojecting from the rear of the rail brace. Whenmoving the rail, The toolhead on the crossrail is controlledas first loosen the two clamp nuts to direction of feed (right at the rear of the or left, up or down) column and the two clampnuts at the front; by the lever on therear of the feed box. The then with the handcrank vertical feed is engaged move the rail to the or disengaged by the desired height. Besure to tighten the clamp nuts upper of the two levers on the front of the feed before doing any machining. box. Shifting the rear, or directional,lever to the down position and engaging the clutch lever by On machines havingpower rail elevation, a pressing it downward give,i downward feed-to the toolhead. Shifting the motor is mounted within the railbrace and directional lever to connectedtotheelevating the up position givesan upward feed. mechanism. peration of the motor, forward.or reverse, is The bottom clutch leveron the front of the cooiled by pushbuttons suitablymarked. The feed box engages the horizontalfeed of the ciam uts have the same useon all machines toolhead. The directional leveron the rear of the whethe manual or power elevationis used. box in the down position feedsthe head toward / tht left, or away from theoperator. In the up Holding the Work position it feeds toward the right. The ball crankon top of the vertical slide (toolhead feed) is for the hand The various accessories generallyused in movement, up or planer or shaper workmay make the difference down, of the toolslide. A graduateddial directly between a job well done and below the crank indicates the a poor job. There amount of travel. arenosetrules on utilizationof planer For traversing the toolheadup or down, a accessoriesforclamping down a piece of handcrank is provided foruse on the upper of the two squared shaftsatthe end of the crossrail. Horizontal traverse isaccomplished by using the crank on the lowersquared shaft. When using either of thesesquared shafts, be sure that the directional leveron the rear of the feed box is in the centralor neutral position. Lock screwsareprovided on both the cross-slide saddle and the verticalslide so that these slides may be locked inposition after the desired tool 'setting has beenmade. 11.15 Figure 12-14.Step 6Tock.

12-16 3s 1 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

T-slots. Figure 12-14 illustrates a step block used STEP BLOCK GOOSENECK' WORK CLAMP with the clamps shown it 5-32. At some tHe it may be necessary clamp an irregular E. Aece of work to'.he planer table. A typical pplication for holding irregularly shaped work is illustrd ed in figure 12-15; here an accurately machined step block is used with a gooseneck clamp. Figure 12-16 illustrates the correct and incorrect methods of clamp application. MACHINE TABLE For leveling and supporting work on the planer table, jacks of different sizes are used. 28.231 The conical point screw (fig. 12-17) replaces the Figure 12-15.Application of step block and clamp. swivel type screw for use in a corner. Extension bases (fig. 12-17, C, D, E, and F) are used for increasing the effective height of the jack. workresults will depend upon your ingenuity and experience. SURFACE GRINDING ON THE PLANER One means of holding down work on the worktable is by using clamps. The clamps are While it is not a recommended practice, it is bolted down to the worktable by way of the possible, with the use of a toolpost grinder, to use the planer as a surface grinder. Most of the large tender and repair type ships of the Navy BLOCK have surface grinders on board, but due to space 'limitations this machine may not always have a WORK large enough capacity to accommodate large CORRECT INCORRECT workpieces.Itsometimesmaybecome necessarytoutilizethe planer as a surface grinder. Basically speaking, itis a matter of

CORRECT INCORRECT

BLOCK STRIP LOCK A

) WORK

CORRECT INCORRECT

B CONICAL POINT SCREW A. JACK

' Isom 11 CORRECT INCORRECT

11C, 0,E, AND F EXTENSION BASES

28.232 28.233 Figure 12.16. Correct and incorrect clamp applications. Figure 12-17.Planer jack and extension bases.

12-17 MACHINERY REPAIRMAN 3 & 2

replacing the toolbit with the toolpostgrinder procedures, you should have and computing feeds ed speeds for no difficulty in grinding applying the information containfdinthis instead of planing. Prior to attemptingsurface sectiontotheoperation of any model of grindingontheplaner, a thorough pantograph engraver. understanding of chapter 13 of thismanual will be necessary. PANTOGRAPH ENGRAVER UNITS Once the grinding jobis completed, the planer must be extensively cleaned inside and The pantograph engraving out. The oil in the hydraulicsystem must be machine, shown in figure 12-19, consists of fiveprincipal parts: filtered or changed prior to furtheroperation. the The planer, unlike the surface supportingbase,pantographassembly, grinder, has no cutterheadassembly, built-in protection against thegrinding parti.:les worktable,and left by the grinding operation. copyholder.

The same safety precautionsobserved for Supporting Base theshaperapplytotheplaner.Standard machineshoppracticesshouldalwaysbe observed. The supporting base isa heavy, rigid casting which supports the entire piece ofmachinery. If the machine table is not level, thebase should be PANTOGRAPHS shimmed. If the deck vibratestoo much because of surrounding machinery,the base should be set on rubber or cork pads. Thepantograph tengraving machine)is essentially a reproduction machine. Itis used in the Navy for work suchas engraving letters and Pantograph Assembly numbersonlabelplates,engravingand graduating dials and collars, and inother work The pantographassemblyhasfour. which requires the exact reproductionof a flat connecting arms: a tracer pattern on the workpiece. The pantograph arm, an upper bar, a may lower bar, and a connecting linkbetween the be used for engraving flat anduniformly curved surfaces. tracer arm and the lower bar, andalso the cutterhead link which supports thecutterhead. The relationshipbetween movement of the, Thereareseveraldifferentmodels of stylus point and movement of engraving machines which the cutter is you may have to governed by the relative positionsof the sliding operate. Figure 12-18 shows one modelwhich mounts on a bench or blocks on the upper bar and thelower bar. The a table top and is used pantograph assemblycan be set for a given primarily for engraving small items.It is capable reduction by loosening the sliding of reproducing work at ratios block bolts ranging from 1:1 and settg the blocks at a desirec distance from to 7:1. A 1 to 1ratio will result in the work being the same size the datum lines. This willgive the desired as the pattern being copied, reduction ratio. Theupper and lower bar are while a 7 to 1 ratio will result in.he work being 1/7 the size of the inscribed ith marks (for whole numberand pattern. This particular standard ductions from machine is manufactured by the 2:1to16:1)to New Hermes indicatee position for setting the slider blocks Engraving Machine Corporation. for com only used reductions. The Gorton 3-U pantograph (figure12-19) is commonly used by the Navy. Theprinciples of Cut 'rhead Assembly operation and setup proceduresfor the 3-U machine are similar to those for othermode's of Thecutterheadassemblyhousesthe pantograph type engraving machines.Because of the similarity in operating pcision cutter spindle. Pulleydrives between principles and setup t motor and spindle enableyou to adjust the

12-18 3() Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

( kf

1`

Figure 12.18. Engraving machine.

12-19 31/4t4 MACHINERY REPAIRMAN 3& 2

CONNECTING LINK PPER BAR C OPY- TRACER ARM HOLDER LOWER BAR --. END BOSS

F_OR111 AtaEwa

FORMING GUIDE TRACER STYLUS CUT T:RHEAD ASSEMBLY PtNOLE WORKTABLE

CROSSFEED CONTROL TRANSVERSE FEED

VERTICAL FE ED START CONTROL STOP

28.234X Figure 12-19.Pantograph, Model 3-U(Gorton). spindl.f. speeds. Figure 12-20 gives the spindle 1/4 inch to prevent thecutter from breaking speeds and the arrangement of thedrive belts for whenfeedinginto varying spindle speeds. At the head work. Theseareboth of the cutter automatically obtained inone lever movemcaz. there is a vertbal feed le.9r which provides a A plunger locks the range of vertical movement from 1/16 spindle for flat surface inch to engraving or releasesitfor floating vertical

12-20 382 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

characters used as sample guides. Copy applies MOTOR DRIVE SPINDLE specifically to the standard brass letters or type 2 which are set in the copyholder of the machine eAy co2r_t( and which guide the pantograph in reproducing. 3 Shapes,as distinguished from characters, are called templates or masters. 2-3-A-C 3800 rpm 2-3 -B-C 8100rpm 2-3-A-0 Strictly speaking, copy is not self-spacing; 5300 r om 2-3-B-0 11,00Crpm therefore, the spaces between the characters 1-3-A-C 5300 rrm I-3-B-C 11,000rpm should be adjusted by inserting suitable blank 7400 rpm 1-311-D 15000rpm spacers which are furnished with each set of copy. Each line when setin the copyholder should be held firmly between the clamps. 28.235X Figure 12-20.- Spindle speeds. After setting up the copy in the holder, and before engraving, be sure that the holder is firmlysetagainstthestopscrews inthe movement of 1/2 inch with the forming guide copyholder base. This ensures that the holder is on curved work. The cutterhead assembly is square with the table. Do not disturb these hinged to permit spindle removal fr )m the side, stops; they have been properly adjusted by the making it unnecessary to disturb any work by factory,andanychangewillthrowthe lowering the table. copyholder out of square with the table. The worktable T-slots are parallel with the table's Worktable front edge, making it easy to set up the work and the copy in accurate parallel relation to each Theworktableofthe3-U pantograph other. engraver is 8 inches by 12 inches, flat, and of highly polished cast iron. The worktable surface In addition to copy, circular copy plates are has four 3/8-inch T-slots for mounting a viseor sometimes used for engraving work. A copy table dogs to hold down a piece of work. plate is a flat disk with letters, numbers, and T-slots in the worktable are parallel with the other characters inscribed on the face of the disk front edge of the table. Longitudinal feedcan near the rim. The rim of the plate is notched movetheworktablela inches,whilethe beside each character so that a spring-loaded crossfeed can move the table 11 inches. Vertical indexing pawl can be used to hold the disk in feed of the worktable is 9 3/4 inches. theproperpositionduringtheengraving procedure. The plate is set on a pivot on the Copyholder copyholder and may be rotated 360° so that any character on the plate may be placed in the The copyholder is made of steel castings required position. with beveled grooves or T-slots machined from the solid plate holder. Standard copyholders for SETTING THE PANTOGRAPH the 3-U pantograph engravers have four or six grooves. Two stops are supplied for each groove in the copyholder. The correct setting of the pantograph is determined from a ratio (1) of the size of the SETTING COPY work to the size of the copy layout, or (2) of the desired size of engraved characters to the Lettering,usedinconjunction withan size of the copy characters. This ratio is calleda engraver, is known by various termshowever, reduction.A1:1reductionresultsinan the Navy uses a term "copy" to designate the engraved layout equal in size to the copy layout;

12-21 MACHINERY REPAIRMAN3 & 2

1t.:1 reduction results inan engraved layout 1/16 the size of the copy layout. Table 12-2 provides dimensionsfor setting slider blocks on theupper and lower bars for If a length ofcopy is 10 inches and the reductions length of the finished job is 2 through16. After setting the to be 2 inches, reduction, lock theupper and lower bars in the divide the length of the jobinto the length of the copy: slider blocks by tightening thecapscrews in each block. (Note: For specialreductions between 1 and 2, follow the sample solutionin fig. 12-22.) 10 ÷ 2 = 5 inches

CUTTER SPEEDS Therefore, set the slider blocksat reduction.

If the length of thecopy is 11 inches and the The speeds listed in table12-3 represent length of the finished job isto be 4 inches, the typical speeds for given materials.In using the reduction is: table,keepinmindthatthespeeds recommended willvary greatly, depending on the depth of cut, and particularly 11 ÷ 4 = 2.75 inches the rate at which the cutter is fed throughthe work. Since the 3-U engraversare fed manually, the rate. of feed is subject toa wide variation by individual You will note that reduction 2.75is not rn..rked operators; this will affect thespindle speeds on the pantograph bars. To findthe correct used. slider blocks settings,use the reduction formula in figure 12-21. Run the cutters at highestspeeds possible, and remove stock withseveral light, fast cuts All settings are measuredfrom the first rather than one heavy reduction markingon the upper and lower arms. cut at slower spindle speeds. Always use the highestspeed possible On the model 3-U pantograph,reductions are measured from the line marked without burning the cutter.When cutting steel 2 on the upper and all hard materials,start with a slow speed arm, and NOT the line marked 1. Foraccurately and work up to the fastest setting -recial reductionsuse a hundredth-inch speed a cutter will scale ana a magnifying glass. stand without losing its cuttingedge. Sometimes it may be advisableto sacrifice cutter life to obtain the smoother finish After a special reduction hasbeen set, check possible at higher speeds. With experienceyou will know when the the pantograph. First, placea point into the cutter is running at maximum efficiency. spindle, then raise thetable until the point barely clears the table. Next,trace along an edge of a copy slot in the copyholderwith the tracing GRINDING CUTTERS stylus. If the cutter point followsparallel to the T-slots, the reduction isproper. If the point forms an arc or angle, the Most of the difficulties experiencedin using setting should be very small cutters on small letteringire caused recalculated and reset. If the pointstill runs off, by improper grinding. The loosen either of the slid,;I blocks and tap one cutter point must be accuratelysharpened.Whentrouble way or the other. until the path of thepoint is is parallel to the T-slots. experienced, usually the point isburned, or the flat is either too highor too low. Perhaps the For 1:1 reduction, transfer clearance does notrun clear out to the point. the stylus collet Stoning off the flat with.a small fine oilstone from the end boss of thetracer arm to the will make the cutting edge second boss on thearm. Set the lower slider keener. block on the graduation marked"1 and 2," and A cutter the upper bar slider block can be made to run almost' on graduation 1. perfectly by sharpening thecutter in the spindle 12-223,s-A Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

\ I 20. 0390., A 1)--- 1508 ..990mm "'war ''''"" I I 12 .7450' Sairr Am- Vl-723.723m/44fie /i4Phyra,a+ Cernava CONSTANT _ f /0, 0/95' 1 44)---4 #\CONSTANT1107:4.2483' Ay 617,9,. gge t2.54 49. 5 mogibe "Pier 16414 --:-.1-1,._ 90701.) Cheer 5sy consow. ..e .745er -i. 3 (ere /?etlydo, 0./). Loney' 412r Constad a 20 .0390. 4 2/21',Ped4007.

EXAMPLE: REQUIRED THE SETTINGSIN INCHES FOR REDUCING 4 TO I. For LOP/ER ...Vokr gar UPPER afeSi- Lower ay. F;r5/ dude /,(Moe/ S/40- Aar Cen/er °is - Altict-hon 4 ola9 .039o. Cars /nn/ bree /2.7450' by /he Rethic/ion 7' 5.0097' d0.0/95" Aped pia a ecws/ant 9, I. acergron. / 5.0097' .0 Lipper sAltv. go. Cen/ers. Ce/ilers_ Sub/roc/Awn 7-0-0.3 iftckt-hon Repeal- 5 0 ) /2 .7450'4e- 2.5489' Ocrance lo se/ /ndex edge 0/1 Lower 54/b/rael from 2483% tOar gar $/4*.r Bar *4,21 from Giaduahon 2. Cons/21/ Sew DehAn safe /ch. as/once /.6994' /o se/ //vex E.,* on Upper Sk/r gir Heat? from aratiafion 2. See be/ow s4e/ch.

PANTOGRAPH SET TO THE '4.0 REDUCTION. To se/ Measuredin /he Pantorapn inches from for any desired 4oee./O/ Scale o/ Re- 6eadmaticr deichog0.5per o6ove Fvrmub or as per Sc/vdei/e, rae-- /Ous Red/ad/Otos 9 /ve/7 POce /he Seve/4a, index Edges A of /he Shaors away //o/n Me Zeesmailed 2 an/he Bats,the Ors /axes /aweati. THUS As shown in /he 54e/eh Ar /he i4.t 40 /he Lower S//der gtek mar/ be se/ as a/ :9: 5.0/0' from /he Lint and /he 5// der ger...4 as o/ A' /.699yrom lls Line 2.

28.236X Figure 12.21.- Formula for obtaining special reductions for model 3-U pantocraph. in which it runs. Most pantograph machines have Grinding Single-Flute Cutters provision for removing the cutter spindle from the machine and placing it in a V-block toolhead Before grinding cutters, true up the grinding on the cutter grinder. The cutter is then ground wheel with the supplied with the to the desired shape without removing it from grinder. After inserting the diamond, set the the cutter spindle. toolhead at approximately the same relation to

112-2:96)5 MACHINERY REPAIRMAN 3 &2

Table 12-2.-Reduction Schedulesin Inches and Millimeters

Schedule of Reductions for Schedule of Reductions for Engraving Machine No. 3U Engraving Machine No. 3U ReductionLower BarUpper Bar ReductionLower BarUpper Bar Inches Inches MillimetersMillimeters 2.0 0.000 0.000 2.0 00.00 0.00 2.1 0.477 0.137 2.1 12.12 3.48 2.2 0.911 0.285 2.2 25.14 8.74 2.3 1.307 0.388 2.3 33.19 9.81 2.4 1.870 0.500 2.4 42.42 12.89 2.5 2.004 0.607 2.5 50.90 15.41 2.8 2.312 0.708 2.8 58.73 17.98 2.7 2.598 0.804 2.7 85.98 20.41 2.8 2.883 0.894 2.8 72.71 22.72 2.9 3.109 0.980 2.9 78.98 24.90 3.0 3.340 1.082 3.0 84.83 26.98 3.1 3.555 1.140 3.1 90.30 28.95 3.2 3.757 1.214 3.2 95.44 30.83 3.3 3.947 1.284 3.3 100.26 32.62 3.4 4.126 1.352 3.4 104.79 34.33 3.5 4.294 1.416 3.5 109.07 35.97 3.6 4.453 1.478 3.8 113.11 37.53 3.7 4.604 1.537 3.7 116.93 39.03 3.8 4.746 1.593 3.8 120.55 40.48 3.9 4.881 1.647 3.9 123.98 41.84 4.0 5.010 1.899 4.0 127.25 43.18 4.1 5.132 1.749 4.1 130.35 44.43 4.2 5.248 1.797 4.2 133.31 45.85 4.3 5.359 1.844 4.3 136.13 48.83 4.4 5.485 1.848 4.4 138.82 47.96 4.5 5.586 1.931 4.5 141.39 49.05 4.8 5.863 1.972 4.8 143.84 50.10 4.7 5.758 2.012 4.7 148.20 51.11 4.8 5.845 2.051 4.8 148.48 52.09 4.9 5.930 2.088 4.9 150.62 53.04 5.0 8.012 2.124 5.0 152.70 53.95 5.1 8.090 2.159 5.1 154.89 54.84 5.1. 8.188 2.193 5.2 156.81 55.89 5.3 8.239 .2.225 5.3 158.48 58.52 5.4 8.309 2.257 5.4 180.24 57.33

28.236.01X 12-24 3S' I; Chapter 12-SHAPERS, PLANERS, AND ENGRAVERS

Table 12.2.- Reduction Schedules in Inches and Millimeters-Continued

Schedule of Reductions for Schedule of Reductons for Engraving Machine No. 3U Engraving Machine No. 3U ReductionLower BarUpper BarReductionLower BarUpper Bar Inches Inches MillimetersMillimeters 5.5 6.376 2.288 5.5 181.95 58.10 5.6 6.441 2.317 5.6 163.60 58.86 5.7 8.504 2.346 5.7 165.20 59.59 5.8 6.564 2.374 5.8 166.74 60.30 5.9 6.623 2.401 5.9 168.23 60.99 6.0 6.680 2.428 6.0 169.66 61.66 6.1 6.734 2.453 6.1 171.05 62.31 6.2 6.787 2.478 6.2 172.40 62.95 6.3 6.839 2.502 6.3 173.70 63.56 6.4 6.888 2.526 6.4 174.97 64.16 6.5 6.937 2.549 6.5 176.19 64.74 6.6 6.983 2.571 6.6 177.38 65.31 6.7 7.029 2.593 6.7 178.53 65.87 6.8 7.073 2.814 6.8 179.64 66.40 6.9 7.115 2.635 6.9 180.73 66.93 7.0 7.157 2.655 7.0 181.78 67.44 7.1 7.197 2.673 7.1 182.8' 67.94 7.2 7.236 2.694 7.2 183.80 68.43 7.3 7.274 2.713 7.3 184.77 68.;)0 7.4 7.312 2.731 7.4 185.71 69.37 7.5 7.348 2.749 7.5 186.63 69.82 7.6 7.383 2.766 7.6 187.32 70.26 7.7 7.417 2.783 7.7 188.39 70.70 7.8 7.450 2.800 7.8 189.24 71.12 7.9 7.483 2.816 7.9 190.07 71.53 8.0 7.515 2.832 8.0 190.87 71.94 9.0 7.793 2.974 9.0 197.94 75.53 10.0 8.016 3.090 10.0 203.60 78.48 11.0 8.198 3.186 11.0 208.22 80.93 12.0 8.350 3.268 12.0 212.08 83.01 13.00 8.478 3.338 13.0 215.34 84.78 14.00 8.588 3.399 14.0 218.13 86.32 15.00 8.683 3.452 15.0 220.56 87.67 16.00 8.767 3.499 16.0 222.68 88.86

28.236.02X r47 MACHINERY REPAIRMAN 3 & 2 IIMIIMIM

TRACER ARM SCHEDULE OF VARIOUS REDUCTIONS 10.0 95" BETWEEN 1:1 AND 2:1 ON MOD. SU PANTOGRAPH WITH TRACING STYLUS PANTOGRAPH IN NEAREST HOLE OF ARM. CENTERS MEASUREMENTS IN INCHES UPPER SLIDER BAR DISTANCE TO SET DISTANCE TO SET 25 REDUCTION INEXED EDGE INDEX EDGE All AI, AI LOWER SLIDER BARUPPER SLIDER e F R MP IV UPPER BAR HEAD FROM GRAD. HEAD FROM GRAD. 10.0195" CONSTANT MARKSI B2 MARK I LOWER BAR CONSTANT .0 0 0 .1 .911" .303" .2 1.670" .579" EXAMPLE .3 2.712" .631 ,4 ' REQUIRED. THE SETTING IN INCHES FOR REDUCING 1,5 TO 1 2.963" 1.062" FOR LOWER SLIDER BAR FOR UPPER SLIDER BAR .5 3.340" 1.275" STEP I. DIVIDE TRACER ARM CENTERS BY THE Ai 3.757" 1.471" STEP I.DIVIDE UPPER SLIDER BAR CENTER .7 REQUIRED REDUCTION THUSI 4.126. 1.151" DISTANCC. BY THE REDUCTION 4EQuiRED .6 4.453" 1.921- TRACER ARM CENTERS 10.0195' PLUS A CONSTANT OF ONE. .9 4.746" ',ale" REQUIRED REDUCTION 1.5 66. 9' REQUIRED REDUCTION1.5 STEP 2. SUBTRACT THE QUOTIENT FROM THE LOWER CONSTANTI.0 BAR CONSTANT. 10.0195" 2.5 - 6.679" UPPER SLIDER BAR CENTERS 12.7055.096" 3.340" FOR OTHERREDUCTIONSUSE FORMULA STEP 3' 2.5 THE RESULT IS THE DISTANCE TO SET INDEX STEP2.SUBTRACT THE QUOTIENT FROM THE EDGE ON LOWER SLIDER BAR HEAD FROM UPPER BAR CONSTANT 6.3725" TRADUATIONI a 2. STEPS.THE RESULT IS THE - 5.099" FOR GREATER REDUCTIONS USE SCHEDULE D1STAYcE TO SET 1.2745" AS PER INSTRUCTION BOOK WITH TRACING INDEX EDGE ON UPPER STYLUS AT EXTREME END OF PANTOGRAPH ARM SLIDER WAR HEAD FROMGRADUATION I.

28.237X Figure 12-22.-Formula for obtainingspecial reductions between 1 and 2.

the wheel as shown in figure 12-23.Then swing bakelite plates, a 30° angle is the diamond across the face of the used. Now place wheel by the cutter in the toolheadand rough grind to rocking the toolhead in much thesame manner approximate size by swinging as for grinding a cutter. In dressing the wheel, across the wheel's a face. Do not rotate thecutter while in contact cut of 0.001 or 0.002 inch shouldbe the very with the face of the wheel maximum. If the diamond fails to but swing straight cut freely, across,turningcutterslightly BEFORE or turn it slightly in the toolhead to presentan AFTER contact with wheel. This unused'portion of the diamond to the wheel. will produce a series of flats as in figure 12 -24B.Now, grind off the flats and produce ROUGH AND FINISH a smooth cone by feeding GRINDING the cutter into the wheel androtating the cutter CONICAL POINT.-Set the grindertoolhead at the same time. The finished to the desired cutting edge angle cone should look (fig. 12-24A). like figure 12-24B, smooth andentirely free This angle usually varies from 30°to 45°, from wheel marks. depending upon the work desired.for most sunken letter or design engraving on metal or GRINDING FLAT TO CENTER.-Thenext operation is to grind the flatto center. For very

28.238X 28.239X Figure 12-23.-Position of diamondfor truing a grinding Figure 12-24.-Grinding conical point.A. Cutter angle. wheel. B. Rough and finished conical shape.

12-26 1/4is Table 113.-ant Spods

Revolutions per minute for high speed steel cutters, single-flute type. Usetwo-thirds of speeds shown for l- and 4-flute end mills; one-half speedsfor 6-flute end mills,

Cutter diameter (at cutting point)

.1M1=IMMIMAIIII

Materials and Feeds 1/32" 1/16" 1/8" 3/16" 1/4" 5/16" 3/8" 7/16" 1/2"

Speeds (rpm)

Hardwood (650.800 ft. /min.)- - -- 10,00010,000 10,00010,00010,000 9,000 8,000 7,000 6,000 to to to to to

20,00020,00020,00020,00020,000 tin

*Bakelite (170.250 ft. /min. )--- 10,000 8,000 6,000 9,000 ro 3,000 2,200 1,800 1,500 1,300

"Engraver's brass and 10,00010,00010,000 8,000 6.000 5,004 4,000 3,500 3,000 aluMinum (375.425ft. /min. ) to to to,

15,00015,00015,000

Cast iron (130.250 ft. /min. )--- 8,000 7,500 5,500 3,500 2,500 2,000 1,650 1,400 1,200

Hard bronze and machine steel 7,000 6,00 3,000 2,200 1,600 1,200 975 800 700 (80.200 ft./min.)

Annealed tool steel (70.100 ft. / 5,000 4,500 2,300 1,600 1,200 1,000 850 725 600 min.)

Stainless steel, Monel (45.75 3,500 2,754 1,400 1,050 700 575 500 435 350 ft./min.)

Very hard die and alloy steels 2,000 1,250 800 600 475 400 350 300 250 (30.45 ft./min.)

'Also celluloid, hard rubber, pearl,ivory, and synthetic plastics. "Slightly lower speeds for ordinary brass, zinc, copper, silver, gold,soft bronze, and German silver. 30'9

3;q12&278 MACHINERY REPAIRMAN 3 & 2

CUTTING EDGE

BACK SIDE 28.240X OF CUTTER Figure 12-25.Grinding the flat. A. Fiatnot ground to center. B. Flat ground to center.

28.241X small, delicate work it is absolutely essential to Figure 12-26.First operation in grinding clearance. grind this flat EXACTLY to center. If the flat is oversize, you can readily see it after grinding the cone, and the point will appear as in figure work, regardless of how perfectit may be 12-25A. To correct this, grind the flat to center farther out on the taper of the cone. as in figure 12-25B. TIPPING OFF THE CUTTER POINT.For GRINDING CHIP CLEARANCE.The engraving hairline letters up to 0.0005 inch in cutter now has the correct angle and a cutting depth, the cutter point is not flattened, or edge, but has no chip clearance. This must be TIPPED OFF. For all ordinary work, however, it provided to keep the back side of the cutter is best to flatten this point as muchas the work from rubbing against the work and heating will permit. Otherwise, it is very difficult to excessively, and to allow the hot chips to fly off retain a keen edge with such a fine point, and readily. The amount of clearance varies with the whenthepointwearsdown,thecutter angle of the cutter. The procedure for grinding immediately fails to cut cleanly. Tipping off is chip clearance is as follows. usually done by holding the cutter in the hands Gently feed the cutter into the face of the at the proper inclination from the grinding wheel. Do not rotate the cutter. Hold the back wheel face and touching the cuttervery lightly (round side) of the conical point against the againstthewheel, or by dressing with an wheel. Gradually feed in toward the wheel while oilstone.Angle A(fig.12-27)shouldbe rockingthecutter continuouslyacrossthe wheel's face and without turning, untila flat is ground which runs out exactly at the cutter point (fig.12-26). Check this very carefully, with WIDE AS POSSIBLE a magnifying glass if necessary, to be sure you have reached thepoint withthisflat. Be extremely careful not to go beyond. Rough away stockas in figure12-24B. \B Rotate the cutter against the face of the wheel A SEE to grind away all stock on the back of the TABLE conicalside,up tothecuttingedge. Be 12-4 extremely careful not to turn the cutter too far and thus grind away part of the cutting edge. Clean up all chatter marks. Be careful of the point; this is where the cutting is done. If this 28.242X point is incorrectly ground, the cutter will not Figure 12-27.A tipped off cutter.

12-28 3 Chapter 12SHAPERS, PLANERS, AND ENGRAVERS

Table 12-4.Rake Angles for Single-Flute Cutters

Material to be cut Angle B (See figs. 12-27)and 12-28) Tool steel 5-10degrees Machine steel 10-15degrees Hard brass 15-20degrees Aluminum 20-25degrees Bakelite, celluloid, wood, fiber 20-25degrees

28.2

approximately 3°; this angle, ,..auses the cutterto grinding the flat to center (easily checked wi bite into the work likea drill, when fed down. micrometer), clearance is ground by feedin Angle B (fig. 12-27) varies, dependingon the the required amount toward the wheel material to be engraved. Table 12-4 willserve as turning the cutter untilallstock has 1 a guide in maintaining angle B. removed from the back (round side) rightu thecuttingedge.Table 12-5 prov Grinding Square-Nose information on chip clearance for variouss Single-Flute Cutters cutters.

The properly ground square-nose single-flute Grinding Three- and Four-Sided Cutters cutter should be similar to the illustration in figure12-28. When square-nosecuttersare Three- and four-sided cutters (see fig. 12 ground, they should be tipped off in thesame are used for cutting small steel stamps and manner as described in connection with figure small engraving where a very smooth finis 12-27. All square-nose cutters have peripheral desired. The index plate on the toolheadcc clearance ground back of the cutting edge.After spindle has numbered index holes for inde) to grind three- and four-sided cutters.

Set the toolhead for the desired angle. 1 the pin in the index hole for the desiredrim SEE TABLE 12-4\ of divisions and grind the flats. Now with loosening the cutter in the toolhead collet, r

28.243X Figure 12-28.Square-nose cutter with properly ground 28.244 tip. Figure 12-29.Three-sided cutter.

12-29 MACHINERY REPAIRMAN 3 & 2

Table 125.Chip Clearance Tablefor Square-Nose Cutters

Cutter diameter Clearance Cutter diameter Clearance Inches Inches Inches Inches 1/10 .004 1/4 1/8 .010 .006 5/16 .012 5/32 .006 3/8 3/16 .015 .008 7/16 .015 1/2 .020

28.244.0

Table 12-6.Clearance Angles for 3- and4-Sided Cutters

Degrees of cutting 45° 40°35° 30°. 25° 20° 15° 10°5° Angle of clearance:(Degrees)

3 sides 261/223 19 1/216 13 101/2 71/25 21/2 4 sides 351/223251/2 22 1/2181/2141/2 10 7 31/2

28.245.0

the toolhead to theproper clearance angle. Clearance angles are listed in table12-6.

PANTOGRAPH ATTACHMENTS

Some attachments commonly usedwith the pantograph engraving machineare: copy dial holders, indexing attachments,forming guides, and rotary tables. Theuse of these attachments extendsthecapabilities of the pantograph engravingmachine fromflat,straightline engraving to include circular work,cylindrical work, and indexing.

The copy dial holder shown infigure 12-30 28.245X Figure 12-30.Copy dial holder andplate. is used instead of the regularcopyholder when a circular copy plate is used. Thisholder has a

12-30 3:,)3 Chapter 12SHAPERS, PLANERS,AND ENGRAVERS

spring-loaded indexing pawl whichis aligned the dividing head (usedon the milling machine) with the center pivot hole. This pawlengages in isused the notches in circular for this purpose. The workto be copy plates to hold the engraved is held in this attachmentand may be plate in the required position forengraving the indexed for any number of divisions character concerned. available on the plate. Figure 12-31 showsa micreter, An indexing attachment suchas that shown collar being held for graduation and in en ving. figure12-31 may be usedfor holding A forming guide (sometimes called cylindrical work to be graduated. radius In some cases plate)isusedwhenengraving hntlrical

71Meammem.

28.246X Figure 12-31.Using an indexingattachment.

12-31 3!)..1 MACHINERY REPAIRMAN 3 & 2 surfaces. The contour of the guidemust be the These stops will not be moved until the entire ev.ct opposite of the work; if the work is job is completed. concave the guide must be convex and vice 2.Set the circular plateon the copyholder versa. The forming guide is mountedon the so that the plate can be rotated by hand. Check forming bar. (See fig. 12-32.) When the spindle to ensure that the indexing pawlengages the floating mechanismisreleased,the spindle notch on the rim so that the plate will be steady follows the contour of the forming guide.This while tracing the character. causes the cutter to move vertically in direct 3.Setthemachineforthe required relation to the contour of the formingguide. reduction and speed, and adjust the worktable so that the spindleisinposition over the The rotary table shown in figure12-32 is workpiece. used for holding work suchas face dials. It is similar to the rotary table used 4.Clamp the first workpiece in placeon on milling the worktable. (Aligning stops, step 1,ensures machines. The rotary table is mounteddirectly accurate positioning.) on the worktable and provides ameans of rapid 5.Rotate the circular plate until the letter graduation and of engraving the faces of disks. A is under the tracing stylus and theindex pawl is engaged in the notch. USING A CIRCULAR COPY PLATE 6.Engrave the first piece with the letterA. Check the operation for required adjustmentsof the machine. The circular copy plate might beefficiently 7.After the first piece is fmished, usedinengraving remove it anumber ofsimilar from the machine. Do not changethe alignment workpieceswithsinglecharactersused of the aligning stops (step consecutively.For example, 1), worktable, or to engrave 26 copyholder. Place the second workpiecein the similar workpieces witha single letter, but with each machine. Index the circular plate to thenext piecehavingadifferentletter,the letter and proceed as previously de'Acribed. following setup can be used: 8.Continue loadingtheworkpiece, indexingtheplatetothe next 1.Set the workpiece conveniently character, on the engraving,andremovingthework,until worktable and clamp two aligningstops in place. completion of the job.

ENGRAVING A GRADUATED COLLAR

To engrave a graduated collar,as shown in figure12-31, a forming guide and indexing attachment are used. The circularcopy plate can also be used to speed up the numberingprocess. After each graduation is engraved, thework is indexed to the next division until thegraduating is completed. When engravingnumbers with more than one digit, offset the work angularly by rotating the workso that the numbers are centered on the required graduationmarks.

ENGRAVING A DIAL FACE

28.247X A rotary table and circularcopy plate might Figure 12-32.A rotary table. be used in engraving the dialface shown in 12-32

%-ft.ra Chapter 12 SHAPERS,PLANERS, AND ENGRAVERS figure 12-33. Note that the figures on the right 5. Rotate the side of the dialare oriented differently from copy plate until the copy those on the left side; this character for makinggraduation marks is aligned illustrates the usual with the center of the method of positioningcharacters on dials. The copy plate and the center graduationsare of the work. Set thestylus in this mark. Now, radiallyextended from the by feeding the worktable center of the face.' Thegraduations also divide straight in toward the the dial into eight equal back of theengraver, adjust the tableso that the divisions. cutter will cut the graduation To set up andengrave a dial face, proceedas to the desired follows: length. 6. Startthemachineandadjustthe 1. Set the reduction required.'The size of engraver worktable vertically forthe proper the copy on thecircular copy plate andthe depth of cut. Thenclamp the table to prevent desired size of numerals on the work are the misalignmentofthework.Anyfurther basis for computing thereduction. movement of the work willbe made by the 2. Set the copy plateon the copyholder, rotary table feed mechanishm. ensuring that it is freeto rotate when the ratchet 7. Engrave the first is disengaged. graduation mark. 8. Using the rotary tablefeed wheel, rotate 3. Mount a rotary, tableon the worktable the dial to theproper position for the next of the engraver.Position the dial blank graduation. As there rotary table so that on the are eight graduations here, the center of the dial rotate the table 45°;engrave this mark and coincides with thecenter of the rotary table. continue until the circle Clamp the dial blank is graduated. You will to the rotary table. now be back to the startingpoint. (Note: The 4. Place the tracingstylus in the center of circular copy plate isnot moved during the the circular copy plateand adjust the worktable graduating process.) so that the center of the dialis directly under 9. To engrave numbers the point of the cutter. positioned as shown on the right side of the dialin figure 12-33, move the worktableso that the cutter is in position for engraving thenumbers. Rotate the circular copy plateto the numeral 1 andengrave it. Rotate the rotarytable 45° and the circular copy piste to 2, andengrave. Continue this Irocerc 'anti' all the numbersare engraved. If *.:(( a. more) digit numbersare required, offset tit. dial as previouslydescribed. 10. To engrave thenumbers, as shownon the left side of thedial in figure 12-33,rotate the copy plate to therequired number and then, using the crossfeed andlongitudinal feed of the engraver table, position thecutter over the work at the point where thenumber is required. This methodrequiresthattheworktablebe repositioned for eachindividual number. As previously stated,movement of theengraver worktable in twodirections results in angular misalignment of the characterwith the radius of 28.248 the face; in thisexample, angular misalignment Figure 12-33.A dial face. isrequired.

12 -32. '4)6 CHAPTER 13

PRECISION GRINDING MACHINES

Modem grinding machinesare versatile and sometimes a universal grinder. The UNIVERSAL are used to perform work of extreme accuracy. } grinder is similar to a tool andcutter grinder These machines are used primarily for finishing' except that it is designed for heavier work and surfacesthathave been machined in othei usually has a power feed system anda coolant machinetooloperations.Surfacegrinders, system. sylindrical grinders, and tool and cutter grinders, Before operating a grinding machine,you installedin most repair ships, can perform must understand the underlying principles of practicallyallofthegrindingoperations grinding and the purpose and operation of the required in Navy repair work. various controls and parts of the machine. You A Machinery Repairman must demonstrate must also know how to set up the work in the an ability to: (1) mount, dress, and true grind machine. The setup procedures willvary with machine wheels; (2) perform precision grinding the different models and types of machines. operations using a magnetic chuck; (3) grind Therefore, you must study the manufacturer's cutter bits (tool bits) on a surface grinder for technical manual to learn specific procedures for Acme and square threading; and (4) setup and using a particular model of machine. grind milling cutters usinga . SPEEDS, FEEDS, AND COOLANTS To perform these jobs, you must havea knowledge of the construction and principles of As with other machine tools, the selection of operation of commonly used grinding machines. proper sp.ied,. feed, and depth of cut isan You gain proficiency in grinding through important factor in successful grinding. Also, the practical experience. Therefore,you should take use of coolants may be necessary for some everyirailable opportunity to watchor perform operations.Thedefinitionsoftheterms grinding operations from setup to completion. "speed," "feed," and "depth of cut,"as applied to grinding, are basically the sameas for other There are many classes of each type of machining operations. grinder. The SURFACE grindermay have a IN FEED is the depth of cut that the wheel rotarytable with a horizontal ora vertical takes in each pass across the work. TRAVERSE spindle,orareciprocatingtablewitha (longitudinal or cross) is the rate that the work horizontal or a vertical spindle. CYLINDRICAL is moved across the working face of thegrinding grinders may be classified as plain, centerless,or wheel. WHhi.:1_ SPEED,unless internal otherwise grinders. The TOOL AND CUTTER lefined, means the surface speed in fpmof the grinder can be appropriately consideredas a grinding wheel. class of . Grinders generally found in the shipboard machine shopare the WHEEL SPEEDS reciprocating table, horizontal spindle (planer type),surfacegrinder; theplain cylindrical Grinding wheel speeds commonly usedin grinder;thetoolandcuttergrinder; and precision grinding vary from 5,500 to 9,500 MACHINERY REPAIRMAN 3 & 2

fpm. You can change wheel speed by changing

the spindle speed or by using a larger or smaller GRINDING wheel. To find the wheel speed in fpm, multiply WHEEL

thespindlespeed(rpm)bythewheel PASS circumference (inches) and divide the product 174ND. PASS by 12. IRD. PASS 1RD. PASS ICROSS TRAVERSE fpm =(circ. X rpm) 12 WORK 4.4* =7TXD Xrpm LONGITUDINAL TRAVERSE 12 28.427 The maximum speedlisted on grinding Figure 13-1.Surface grinding a flat workplace. wheels is not necessarily the speed at which the wheel will cut best. The maximum speed is based on the strength of the wheel and allows To select the proper work speed, takea cut for a margin of safety. Usually, the wheel will with the work speed set at 50 feetper minute. If have better cutting action at a lower speed than the wheel acts too soft, decrease the work speed. that listed by a manufacturer asa maximum If the wheel acts too hard, increase the work speed. speed. Wheel speed and work speed are closely One method of determining the proper related. Usually by adjusting one or both,you wheel speedistosetthe wheel speed at can obtain the most suitable combination for approximately .000 rpm. Take a trial cut. If the efficient grinding. wheel acts too soft (wears away too fast), increase the speed. If the wheel acts too hard DEPTH OF CUT (slides over the work or overheats the work), decrease the speed. The depth of cut depends on such factorsas material, heat treatment, wheel and work speed, TRAVERSE (WORK SPEED) and condition of the machine. Roughing cuts

During the surface grinding process, the work movesintwodirections.As aflat workpiece is being ground (fig. 13-1), itmoves LATERAL under the grinding wheel from left to right TRAVERSE (longitudinal traverse). The speed at which the work moves longitudinally is called work speed. The work also moves gradually from front to rear (cross traverse), but this movement occurs at the end of each stroke and doeS not affect the work speed. The methodforsetting cross traverse is discussed later in this chapter.

A cylindrical workpieceis ground in a CROSS TRAVERSE manner similar to the finishing process used on a lathe (fig. 13-2). As the surface of the cylinder 440 rotates under the grinding wheel (longitudinal traverse) the work moves from left to right 28.428 (cross traverse). Figure 13-2.Surface grinding a cylindrical workplace.

13 -2 3US Chapter 13PRECISION GRINDING MACHINES

should be as heavy as the machinecan take; lubricating properties of the cutting fluid. The finishing cuts are usually 0.0005 inchor less. addition of the soluble oil to water will alter the For rough grinding, you mightuse a 0.003-inch grinding effect to a certain extent. Soluble oil depth of cut and then, after a trial cut, adjust decreases the tendency of the machine and the the machine until you obtain the best cutting work to rust, thereby eliminating the need fora action. rust inhibitor. When you prepare a mixture of soluble oil and water as a grinding coolant,use A ratio of three parts water to one part of oil. This COOLANTS mixture will generally prove to be satisfactory. The paste compounds are made ofsoaps of The cutting fluids used in grindingopera- either soda or potash, mixed with a light mineral tions are the same types of fluids used in other oil and water to form an emulsion. Asa coolant, machine tool operations. They consist of water, these solutions are satisfactory. However, they water and soluble oil, water solutions of soda have a tendency to retain the grinding chips and compounds, mineral oils, paste compounds, and abrasiveparticles,which maycause synthetic compounds. They also serve thesame unsatisfactory finishes on the work. purposes as in other machine tool operations Mineral oils are used primarily for work plus some additional purposes. As in most where tolerances are extremely smallor in such machining operations,thecoolant helps to work as thread grinding, gear grinding, and crush maintain a uniform temperature between the form grinding. The mineral oils do not haveas tool and the work, thus preventing extreme great a cooling capacity as water. However, the localized heating. In grinding work, excessive wheel face will not load as readily with mineral heat will damage the edges of cutters,cause oils as with most of the other coolants. This warpage,orpossiblycauseinaccurate factor allows you to select a finer grit wheel and measurements. requires fewer wheel dressings. In other machine tool operations, the chips will fall aside and present no great problem; this When selecting a cutting fluid fora grinding is not true in grinding work. Ifno means is operation, consider the following characteristics: provided for removing grinding chips, theycan become embedded in the face of the wheel. This It should have a high cooling capacity to embedding, or loading, will cause unsatisfactory reduce cutting temperature. grinding and you will need to dress the wheel frequently. A sufficient volume of cutting fluid It should prevent adhesion between the will help prevent loading. Otheruses of the work and the chip material. cutting fluid are to reduce friction between the wheel and the work and to help producea good It should be suitable for a variety of finish. machineoperationsondifferentmaterials, In most other machining operations, the reducing the number of cutting fluids needed in primary factor of a cutting fluid is its lubricating the shop. properties. In grinding, however, the primary factoristhecoolingproperty,withthe It should have long life and should not lubricating property second in importance. For\ emit obnoxious odors or vapors harmfulto this reason, water is the best possible grinding ) personnel. coolant, but if used alone,it will rust the machine parts and the work. Generally, when It should not cause rustor corrosion. you use water, you must add a rust inhibitor. The rust inhibitor has very little effecton the It should have a low viscosity to permit cooling properties of the water. gravityseparationofimpuritiesandchips A water and soluble oil mixture givesvery collected by the fluid as it is circulated in the satisfactory cooling results and also improves the cooling system.

13-3 303 MACHINERY REPAIRMAN 3 & 2

It should not oxidize or formgummy BASE deposits which will clog the circulating system. The base is a heavy casting which houses the It should be transparent, allowinga clear wheelhead motor, the hydraulic power feed view of the work. unit, and the coolant system. Ways on top of the base are for mounting the cross traverse table; It should be safe, particularly in regard vertical ways on the back of tM baseare for to fire and accident hazards. mounting the wheelhead unit.

It should not cause skin irritation. The hydraulic power unit includes a motor, a pump, andpipingtoprovide hydraulic The principles discussed above are basic to pressure to the power feed mechanisms on the precision grinding machines. You should keep cross traverse and sliding tables. The smooth, these principles in mind as you study about the direct power provided by the hydraulic unit is machines in the remainder of this chapter. very advantageous in grinding. The piping from this unit is usually connected to power cylinders under the traverse tables. When the machine is SURFACE GRINDER operating automatically, control valves divert pressurizedhydraulicfluidtotheproper Most of the features of the surface grinder cylinder, causing the tableto move inthe shown in figure 13-3 are common to all planer desired direction. Suitable bypass and control type surface grinders. The basic components of valves in the hydraulic system let you stop the this machine are a base, across traverse table, a traverse tables in any position and regulate the sliding worktable, and a wheelhead. Various speed of movement of the tables within limits. controls and handwheels are used for controlling These valves provide a constantpressure in the themovement of the machine during the hydraulic system so that you do not need to grinding operation. secure the system to stop the feed.

CROSS TRAVERSE TABLE [OoToirizi- pCwrikuj

(*HEEL HEA A9SEM The ways on which the cross traverse table

(TAILE fenil are mounted are parallel to the spindle of the wheelhead unit. These ways guide thecross TABLE ANDWITEEL traverse table in a path of movement parallel to the spindle. This allows the entire width of the workpiece to be traversed under the grinding wheel.

Dfii:IFEED The piston in a power cylinder is fastened to the cross traverse table to provide power feed. Manual feed (by means of a handwheel attached to a feed screw) is also available. The amount of crosstraversefeedperstrokeofthe reciprocating sliding table is determined by the

TAAWE ABE thickness (width) of the grinding wheel. During TABLE ii roughing cuts, the work should traverse slightly less than the thickness of the wheel each time it passes under the wheel. For finish cuts, decrease 28.249X the rate until you obtain the desired finish. Figure 13-3.Surface grinder (planer type). When the power feed mechanism is engaged, the

134 U Chapter 13PRECISION GRINDING MACHINES

cross traverse table feeds only at each end of the WHEELHEAD stroke of the sliding table; the grinding wheel clearstheendsof theworkpiecebefore crossfeed is made, thereby decreasing side thrust The wheelheadcarriesthemotor-driven on the grinding wheel and preventing a poor grinding wheel spindle. Youcan adjust the surface finish on the ends of the workpiece. wheelhead vertically to feed the grinding wheel into the work. The adjustment is a leadscrew Thetotaldistanceof crosstraverse on type of mechanism similar to that used on the grinding machines in shipboard machine shops is cross traverse table. A graduated collar on the usually 12 inches or less. It is notnecessary to handwheel lets you keep track of the depth of traverse the full limits for each job. To limit the cut. cross traverse to the width of the work being ground, use the adjustable cross traverse stop The wheelhead is not usually power fed dogs which actuate the power cross traverse because the depth of cut is quite small andany control valves. These dogs, when properly set, lar,:e movement of this part of the machine is limit the cross traverse to the area being ground needed only in setting up the machine. The and secure the cross traverse when the grinding adjusting mechanism is quite sensitive and the wheel reaches these limits. depth of cut can be adjusted in amountsas small as 0.0001 inch. SLIDING TABLE WORKHOLDING DEVICES

The sliding table is mounted on wayson the As surface grinding is usually doneon flat top of the cross traverse table. Recall that the workpieces, most surface grinders have magnetic sliding table moves from left to right, carrying chucks. These chucks are simple touse; the the workpiece under the grinding wheel. work can be mounted directly on the chuckor The top of the sliding table has T-sluts on angleplates,parallels,or other devices machined in it so that work or workholding mounted on the chuck. Nonmagnetic materials devices (such as magnetic chucksor vises) can be cannot be held in the magnetic chuck unless clamped onto the table. The sliding tablemay special setups are used. be traversed manually or by power. The universal viseisusually used when The arrangement for power feed of the table complex angles must be ground ona workpiece. is similar to the cross traverse table. During The vise may be mounted directly on the manual traverse, a pinion turned by a handwheel worktable of the grinder oron the magnetic engages a rack attached to the bottom of the chuck. sliding table. Table stop dogs are provided to limit the Magnetic Chucks length of stroke during manual operation of the sliding table. Table reverse dogsreverse the direction of movement of the table (whenpower The top of a magnetic chuck (see fig. 13-4) feed is used) at each end of the stroke. The isaseriesof magnetic poles separated by reverse dogs actuate the control valve to shift nonmagnetic materials. The magnetism of the the hydraulic feed pressure fromone end of the chuck may be induced by permanent magnetsor power cylinder to the other. by electricity. In a permanent type magnetic chuck, the chuck control lever positionsa series The rate of speed of the sliding table, given of small magnets inside the chuck to hold the in feet per minute (fpm), can usually be adjusted work.In an electromagnetic chuck, electric within a wide range to give the most suitable current induces magnetism in the chuck; the speed for grinding. control lever is an electric switch. Work will not

13-5 MACHINERY REPAIRMAN 3 & 2

A

28.250 Figure 13-4.Magnetic chuck used for holdinga tool grinding . remain in place unless it is in contact withat be ground when it is replaced to least two poles of the chuck. ensure that it is parallel with the grinder table. To grindthe Work held in a magnetic chuckmay become table, use a soft grade wheel witha grit size of magnetized during the grinding operation.This about 46. Feed the,chuck slowly witha depth of is not usually desirable and the work shouldbe cut not to exceed 0.001 or 0.002 inch. Use demagnetized. Most modern magnetic chucks ample coolant to help reduce heat and flush are equipped with demagnetizers. away the grinding chips. Magneticchuckwillbecome worn and scratchedafterrepeateduseandwillnot Universal Vise produce the accurate results normally required of a grinder. You canremove small burrs by The universal vise (fig. 13-5)can be used for hand stoning with a fine grade oilstone.But you setting up work, such as lathe tools,so that the must regrind the chuck toremove low spots surface to be ground can be positionedat any from wear and deep scratches. If thechuck is angle. The swivels can be rotated through 360°. ever removed from the grinder, its table should The base swivel (A of fig. 13.5)can be rotated in 13-6 411 Chapter 13PRECISION GRINDING MACHINES

r

28.258 Figure 13-8.Grinding a spacer on a surface grinder.

28.251X Figure 13-5.Universal vise (mounted on a tool and 4. Set the longitudinal traverse speed of the cutter grinder). (A) Base swivel; (B) intermediate worktable. For rough grinding hardened steel, swivel; (C) Vise swivel. use a speed of about 25 fpm; for finishing, use 40 fpm.

a horizontal plane; the intermediate swivel (B of 5. Set the cross traverse mechanism so that fig. 13-5) can be rotated in a vertical plane; the the table moves under the wheela distance vise swivel (C of fig.13-5) can be rotated in slightly less than the width of the wheel after either a vertical or a horizontal plane depending each pass. (Refer to the manufacturer's technical on the position of the intermediate swivel. manual for specific procedures for step; 4 and 5.) USING THE SURFACE GRINDER 6. Start the spindle motor; let the machine To grind a hardened steel spacer similar to run for a few minutes and then dress the wheel. that shown on the magnetic chuck in figure 13-6, proceed as follows: 7. Feed the moving wheel down until it just touches the work surface; thenmove the work 1. Place the workpiece on the magnetic clear of the wheel, using the manualcross chuck. Move the chuck lever to the position that traverse handwheel. Set the graduate feed collar energizes the magnetic field. on zero to keep track of how much you feed the 2. Selectandmountanappropriate wheel into the work. grinding wheel. This job requiresa straight type wheel with a designation similar to A60F12V. 8. Feed the wheel down about 0.002 inch 3. Set the table stop dugs so that the sliding and engage the longitudinal power traverse. table will traverse the work clear of the wheel at Using the cross traverse handwheel, bring the each end of the stroke. If power traverse is to be grinding wheel into contact with the edge of the used, set the table reverse dogs. workpiece.

13.7 4u3 MACHINERY REPAIRMAN 3 & 2

9. Engage the power cross traverse and let CYLINDRICAL GRINDER thewheelgrindacrossthesurface of the workpiece. Carefully note the cutting actionto The cylindrical grinder is used for grinding determine if you need to adjust the wheel speed work such as round shafts. Althoughmany of or work speed. theconstruction features of the cylindrical grinder are similar to those of surface grinders, 10. Stop the longitudinal andcross traverse thereisaconsiderabledifferencein and check the workpiece. the functionsofthecomponents.Cylindrical grindershave no crosstraversetable. An Figure 13-5 shows a universal vise being used additional piece of equipment (the workhead) is on a tool and cutter grinder in grinding a lathe mounted on the sliding table, and the wheelhead tool bit. In this particular application, the base spindle is parallel to the sliding table. See figure swivel (A) is set to the required side cutting edge 13-7. angle, the intermediate swivel (B) is set to the As in the surface grinder, the base of this side clearance angle, and the vise swivel (C) is set machine contains a hydraulic power unit anda so that the vise jaws are parallel to the table. A coolant system. Longitudinal waysare for the cup type wheel is then used to grind the side of sliding table. Horizontal ways (at right anglesto the tool. The universal vise is resetto cut the the longitudinal ways) are provided to permit end and top of the tool after the side is ground. movement of the wheelhead toward or away from the workpiece. This horizontalmovement The universal vise can also be usedon a is used for feeding the grinding wheelinto the surface grinder for very accurate grinding of work for a depth of cut. lathe cutting tools such ac threading tools. For example, to grind an Acme threading tool,set the vise swivel at 14 1/2° from parallelto the SLIDING TABLE table.Settheintermediateswiveltothe clearance angle. Set the base swivel so that the The sliding table of the cylindrical grinderis tool blank (held in the vise jaws) is parallelto mounted directly on longitudinalways on the the spindle of the grinder. Rememberto leave base of the grinder. This tablemoves back and the tool blank extending far enough out of the forth to traverse the work longitudinally along end of the vise jaws to prevent the grinding the width of the grinding wheel. wheel from hitting the vise. After grindingone An adjustable taper table, locatedon top side of the tool bit, turn the toolbit one-half of theslidingtable,isusedfor grinding turn in the vise and set the intermediate swivel long (small angle) tapers on the workpiece. The to an equal but opposite angle to the angleset taper table is adjusted like the taper attachment for the first side. This setting willresult in a on a lathe. Workholding devices are clampedon clearance equal to the clearance of thefirst side. top of the taper table. The motor-driven workhead is mountedon Another method for grinding single point the taper table. This component holds and tools is to hold the tool ina special jig as rotatesthe work during thegrindingcut. illustrated in figure 13-4. The jig surfacesare cut Variable speed drive motorsor step pulleys are at the angles necessary to hold the toolso that provided for changing the rate of rotating speed the angles of the tool bit are formed properly. of the workpiece to meet therequirements of the job. When using either method for grinding tool A chuck, a center, or a faceplatecan be used bits, check the tool bit occasionally withan in mounting work on the workhead.Center rests appropriate gage until you have obtained the and steady rests are also used in conjunction correct dimensions. To save time, you can rough withtheworkheadformountinglong grind the tool bit to approximate sizeon a workpieces for cylindrical grinding. bench grinder before setting the tool bit in the jib. On most cylindrical grinders used bythe Navy, the workhead is mountedon a swivel base

13-8

4 U,1 Chapter 13PRECISION GRINDING MACHINES

!TAPER TABLE TAPER TABLE r. ADJUSTING DEVICE tft

!SLIDING TABLO

"1r

28.252X Figure 13-7.Cylindrical grinder (with workhead andfootstock mounted). to provide a means of setting the work for The same center holes are then used for the grinding relatively large taper angles. grinding setup. Center restsor steady rests (as applicable) are used to support long workor WHEELHEAD overhanging ends. Short workpiecescan be held , in chucks. For internal grinding (on machines The wheelhead ofacylindricalgrinder that have an internal grinding spindle), the work movesonhorizontalways(platen).Since is held in a chuck; steady restsare used/ if cylindrical grinding is done with the axis of the necessary, for support. spindle level with the center of the work,no To set up a workpiece for grinding between verticalmovementofthewheelheadis centers proceed as follows: necessary. Some wheelheads are mounted on swivel bases to provide versatility intaper and I. Ensure that the centers in the/workhead angle grinding setups. andfootstock and the center holes in the workpiece are in good condition. USING THE CYLINDRIC GRINDER 2. Clamp a driving dog onto the workpiece. '3. Position the workhead and footstock and set 'the traverse stop dogsso that when the The methods used for settingup stock in a workpiece is in place, the table will cylindrical grinder are similar to the methods traverse used (longitudinally) the proper distance to grind the forlathesetups. Work to be ground surface. betweencentersisusuallymachinedto 4. Ensure that the workhead swivel, the approximate size between centerson a lathe. tapertableattachment, and the wheelhead 13.94v0 MACHINERY REPAIRMAN 3 & 2

swivel are set properly for straight cylindrical end of the longitudinal traverse stroke.) grinding (or for the taper Clamp or angle required if an the table dogs in the correct positionsto limit angle or taper is being ground). longitudinal traverse. 5. Adjust the workhead speed mechanism 11. Start the workhead motor andfeed the to get the proper rotational speed. A slow speed grinding wheel in sufficiently to make is usually used for roughing, while a cleanup a high speed cut (a light cut the entire length of thesurface is used for finishing. to be ground). 6. Set the longitudinal traverse speedso 12. Using power longitudinaltraverse, take a that the work advances from 2/3to 3/4 the cut. Then disengage the power traverse,stop the thickness of the wheel during each revolution of workhead motor and wheelhead rotation,and the workpiece. Fast traverse feed isused for checkthe workpiecefortaper. Make any roughing and a slow feed is used forfinishing. changes required. (If an adjustment ofthe taper 7. Set the workpiece in place and clampthe table attachment isnecessary at this point the footstockspindleafterensuring that both wheel should be dressed again). centers are seated properly and that the driviy: dog is not binding. No information is given hereon methods of 8. Select and mount the grinding wheel. setting the various controls and speedsas there is 9. Start the spindle motor, hydraulicpower a variation in specific methods for each machine. pump, and coolant pump. After the machine has The manufacturer's technical manual run for a few minutes, start the coolant flow and for the machine youaretouseprovidesthis dress the wheel. information. 10. Usingthecrosstraverse mechanism, bring the wheel up to the workpiece andtraverse the table longitudinally by handto see that the TOOL AND CUTTER GRINDER wheel willtravel through the cycle without hitting any projections. (About one-half of the A tool and cutter grinder (fig. 13-8)can best wheel width should remainon the work at each be described as havinga combination of the

WORK HEAD WHEEL HEAD ROOTSTOCK IL --

28.253 Figure 13-8.Tool and cutter grinder (workhaadand footstonk).

13-10 1 U6' Chapter 13PRECISION GRINDING MACHINES

features of the plain cylindrical and the planer damaged beyond, repair if you continue touse type surface grinders. A tool and cutter grinder the cutter in this condition. A good rule for isusedprimarilyforgrinding multi-edged determining when to sharpen a cutter is to cutting tools such as milling cutters, reamers, sharpen it when the wear land on the cutting and taps. The worktable has thesame basic edge is between 0.010 to 0.035 inch. Sharpening construction features as the surface grinder, but cutters at thefirst sign of dullness is both a taper table is mounted on the sliding table so economical and a sign of good workmanship. you can grind tools that have small tapers such Cutters to be sharpened may be divided into as tapered reamers. two groups: (1) those that are sharpened on the relief and (2) those that are sharpenedon the WHEELHEAD face. In the first group are such cuttersas plain milling, side milling, stagger tooth, angle cutters, Thewheelhead,is adjustableintwo and end mills. In the second groupare the directions. It can be moved verticallyon its various form cutters such as involutegear cutters support column and will rotate through 360°. If and taps. The relief on the second type of cutter you need to change the rotational direction of is provided when it is manufactured; the faces of the grinding wheel, simply rotate the wheelhead the teeth are ground to sharpen them. 180°. Additionally, the spindle is double ended, Figure 13-9 shows two methods for grinding allowing you to mount two wheels on the cylindrical cutting tools on a tool and cutter wheelhead. grinder. Part A of figure 13-9 showsa setup for grinding a staggered tooth cutter usinga straight WORKHEAD wheel. Part B of figure 13-9 showsa setup for grinding a reamer using a cup type wheel. Either The basic workholding devices usedon the type of wheel can be used; the cup type wheel tool and cutter grinder are the workhead and the produces a straight clearance angle; the straight footstock (fig. 13-8). When a workhead is not wheel produces a hollow ground clearance angle. provided, you can use a left-hand footstock When you use the straight wheel, set the similartotheright-handfootstock shown spindle parallel to the table. When youuse a mounted on the table in figure 13-8. Also,a flaring cup wheel, turn the spindle at an angle of varietyof tooth rests(forsupporting and 89° to the table. This provides thenecessary gUiding the teeth of a cutter being sharpened) clearance for the trailing edge of the grinding are usually provided. wheel as it is traversed along the cutter. A distinctive feature of most tool and cutter When you grind a cutter, you should have grinders is that there are control handwheels at the grinding wheel rotating as shown in B of both the back and the front of the machine. The figure 13-10. This method tends to keep the dual controls permit you to stand in the most tooth of the cutter firmly against the tooth rest, convenient position to view the work and still ensuring a correct cutting edge. If this method operate the machine. You can usually disengage causes too much burring on the cutting edge, the sliding table handwheel to push the table you may reverse the direction of wheel rotation back and forth by hand. Graduated collarson as shown in A of figure 13-10. If you use the the handwheels are a quick visible guide to latter method, ensure that the tooth being indicate the amount of movement of the various ground rests firmly on the tooth rest during the feed components. cut. CUTTER SHARPENING Dressing and Truing The working efficiency of a cutter is largely determined by the keenness of its cutting edge. Consequently, a cutter must be sharpened at the Sharpening a high-speedsteelcutter or first sign of dullness. A dull cutter not only reamer generally requires a soft grade wheel. A leaves a poorly finished surface, but also may be soft grade wheel breaks down easily and Is MACHINERY REPAIRMAN 3& 2

28.257X Figure 13- 10. Direction ofwheel rotation: (A) Toward cutting edge; (B) Away fromcutting edge.

To compensate for wheelwear and to ensure that all the teethare the same size, rotate the cutter 180° and grind all the teethagain. Be careful not to grind thecutter undersize. To ensure a good cutting edgeon the cutter, there must be a good finishon the clearance angle; therefore,you will occasionally need to dress the grinding wheel.The wheel truing attachment is used for thisoperation and for the initialtruing and dressing operationon the wheel. yr Tooth Rest Blades and Holders

Tooth rest bladesare not carried in stock, so they must be made in theshop. You will find that once you understand therequirements for the blades, you will be ableto readily fabricate various shapes to suit thetypes of cutters that you willbecalled upon to sharpen.Itis 28.253A normally recommendedthat these blades be Figure 13-9.Tool grindingsetups on a tool and cutter made of spring steel. grinder: (A) Straight wheel grindinga milling cutter; The plain (straight) tooth (B) Cup wheel grindinga reamer. rest blade (A in fig.13-11) is used for sharpeningside milling

therefore less likely to burnthe cutter. You should true and dress the wheelprior to starting the sharpening operation andthen re-dress as necessary, depending on the amount ofwheel wear. As you grind each cutter tooth,the grinding wheel diameter decreasesbecause of wear.Thegrinding k. machinedoesnot A ' automatically adjust itself forwear of the wheel. As a result, succeeding teethhave less metal ( removed and the teeth graduallyincrease in size. 128.48X Figure 13-1 1.Typical toothrest blades. 13.12 Chapter 13PRECISION GRINDING MACHINES

for sharpening metal slitting saws and straight tooth plain milling cutters with closely spaced teeth is shown in figure 13-12. Other shapes of tooth rest blades may be made to fit the specific type of cutter or the cutter grinder being used. Holders for the tooth rest blades may be either plain or universal. Figure 13-13A shows a tooth rest blade inplain holder and figure 13-13B shows a tooth rest blade mounted in a universal type holder. The universal tooth rest holder has a micrometer adjustment atits bottom to enable you to make precise up and down movements in the final positioning of the blade. 126.47X Figure 13-12.L-shaped tooth rest blade. SETTING THE CLEARANCE ANGLE cutters, end mills, straight-fluted reamers, or any straight-fluted cutter. The rounded tooth rest Correct clearance back of the cutting edge of blade (B in fig. 13-11) is used for cutters with any tool is essential. With insufficient clearance, the teeth on a helix, shell end mills, and small the teeth will drag, producing friction and slow end mills. The offset tooth rest blade (C in fig. cutting. Too much clearance produces chatter 13-11) is a universal blade that can be used for and dulls the teeth rapidly. The cutting edge most applications. The L-s!9ped tooth rest blade must have strength, and the correct clearance

A B

47

126.48X Figure 13.13. A. Tooth rest blade In plain holder; B. Tooth rest blade In a universal holder. 13-13 409 MACHINERY REPAIRMAN 3 &2

will provide this strength. Figure13-14 shows a typical cutter tooth and theangles produced by grinding. LAND The primary clearance angle isthe angle ground when a cutter requiressharpening. The number of degrees in the PRIMARY primary clearance CLEARANCE angle varies according to thediameter of the ANGLE. cutter and the material beingcut. A large diameter cutter requires lessclearance than a small cutter. Cutters of hardmaterials such as SECONDARY alloy and tool steels require CLEARANCE less clearance than ANGLE cutters of softer materials suchas brass and aluminum. The primary clearance anglesrange from 4° for a large cutter to 13° fora smaller cutter. Some manufacturers of tool andcutter grinders have charts that can assistyou in determining 28.429 the correct clearance angle.The width r`f the Figure 13-14.Cutter clearanceangles. primary land (the surface createdwhen tlu r ,-;mart' clearanceangleisground) 1/4-331tr ltdi!ag I . the size of thecutter. Primary land clearance angle. Determine theamount to raise widths ralige from 0.0005-0.015inch for a small or lower the wheelhead bymultiplying the cutter to 0.030-0.06,-' inei fora large cutter. clearance angle (in degrees)by the diameter of You should grind thq. idndsvery carefully. A the wheel (inches)and then multiplythis ;and that is toonarrow will allow the cutting product by the constant0.0087. edge to chip orwear rapidly. A land that is too When usinga cup wheel, mount the tooth wide will cause thetrailing side of the land rest on the wheelhead.Position the center of the (heel) to rub the work. cutter in the same planeas the tooth rest. Then When thewidth of theprimaryland becomes excessive dueto repeated grindings, you must grind the secondary clearanceangle to reduce it. The secondaryis normally 3° to 5° greater than the primary clearanceangle. The desired clearanceangle is obtained by the positioning of the grindingwheel, the cutter, and the tooth rest. The generalprocedure is to position the center of the wheel,the center of A the work, and the toothrest all in the same plane and then raiseor lower the wheel head the proper distance to give the desiredclearance angle. When using the straightwheel, bring the center of the wheel and thecenter of the work into the same plane by usingthe centering gage (fig. 13-15) or by usinga height gage. Then, fasten the tooth rest to themachine table and adjust to the same heightas the center of the work. Raiseorlowerthewheelheada predetermined amounttogivethecorrect 128.49X Figure 134 6.CenterInggage.

13-14 Chapter 13 PRECISION GRINDING MACHINES raise or lowcr the wheelhead the proper amount PLAIN MILLING CUTTERS to give use desired clearance. Determine the (HELICAL TEETH) amount to raise or lower the wheelhead by multiplying the clearance angle (in degrees) by the diameter of the c. to (in inches) and then Since essentially the same method may be multiply this p'Jduct by the constant 0.0087. usedfor sharpening many cutters, we will discuss in some detail the steps involved in Some tool and cutter grinders have a tilting setting up the machine for a specimen cutter. wheelhead or a clearance setting device. Where a The plain milling cutter with helical teeth will tilting wheelhead is provided, simply tilt the serve very well as an example. The steps are: wheelhead to the desired clearance angle. If you use a clearance setting device, follow the steps 1. Remove all accessory equipment from listed below. the machine table.

1. Clamp a dog to the mandrel on which 2. Clean the table and the bottoms of the the cutter is mounted. footstocks. 3. Mount thefootstocks on thetable, 2.Insert the pin on the side of the dog into allowing just enough space between them to the hole in the clearance setting plate that is accommodate the mandrel with a slight amount Mounted on the footstock. of tension on the spring-loaded center. Loosen the setscrew in the clearance 4. Swivelthewheelheadto89°. (This setting plate and rotate the cutter to the desired allows the end of the cutter io clear the opposite setting(graduations found on the clearance cutting face when you use a cup type wheel.) setting plate). 5. Mount the wheel and wheel guard. 4.Tighten the setscrew. 6. Thin the cutting face of the wheel to not., more than 1/8 inch, using a dressing stick. True 5.Remove the dog. the wheel, using a diamond truing device. When you grind the teeth of end mills, side 7. Usingthecenteringgage,bringthe milling cutters, or stagger tooth cutters, use the wheelhead axis into the same horizontal plane as graduated dials on the workhcad to set the the axis of the footstock centers. clearance angle. 8. Mount the cutter on a mandrel. (A knurled sleeve on the end of the mandrel will help you to maintain an even, effective grip CUTTER SHARPENING SETUPS while the cutter is being ground. 9. Mountthemandrelbetweenthe Tool and cutter grinders vary in design and footstock centers, preferably in such a position in the type of accessory equipment; however, that the grinding wheel cuts onto the cutting most tool and cutter grinders operate in the edge of the teeth. same way. By using only the standard workhead, footstocks,andtoothrestbladeholders, 10. Mount the plain tooth rest holder (with practically any cutter can be sharpened. Most a rounded tooth rest blade) on the wheelhead. cutters can be sharpened using essentially the 11. With the centering gage on, top of the samemethod. A thoroughstudyof the wheelhead and the tip of the gage directly in following sections, along with a little ingenuity front of the cutting face of the wheel, adjust the and forethought, will enable you to sharpen any tooth rest blade to gage height. (This brings the cutter that may be sentto your shop for blade into the same horizontal plane as the sharpening. footstock centers.)

13-15 MACHINERY REPAIRMAN 3 & 2

12. Traversethesaddletowardthe wheelhead until one tooth restson the tooth rest blade; then lock the table intoposition. 13. With a cutter tooth restingon the tooth rest, lower the wheelhead untilthedesired clearance is indicated on theclearance setting plate. If no clearance settingdevice is available, calculate the distance to lowerthe wheelhead using the method previously described.

Before starting the sharpeningoperation, run through it without the machinerunning. This will let you get the feel of themachine and also ensure that thereis nothing to obstruct the grinding operation. Traverse thetable with one hand while the other hand holdsthe cutter against the tooth rest blade.On the return movement, the tooth rest blade will cause the 28.430 mandreltoturninyourhand,thereby eliminating the necessity of moving Figure 13-16.Grinding side teeth ofside-milling cutter the table (Norton Co.). away from the wheel on the returntraverse. In sharpening the teeth ofany milling cutter, grind one tooth, then rotatethe cutter 180° and grind another tooth. Check The procedure for grindingclearance angles the teeth with a varies, depending on the typeof grinding wheel micrometer to ensure that thereis no taper used. If you are using being ground. If there is a cup wheel, swivel the taper, you must remove workhead vertically tomove the tooth toward it by swiveling the swivel tableof the machine. or away from the wheel. The clearance As the width of the landincreases with angle repeated sharpenings, increases as the tooth is swivelledaway from the you will need to grind a wheel. (Fig. 13-17). If. secondary land on the cutter. you use a straight wheel, Never allow the set the cutter arbor horizontallyand raise or primary land to becomegreater than 1/16 inch lower the wheel to change wide because the heel of the the clearance angle. teeth may drag on The clearance angle increasesas the wheel is the work. To control the widthof the primary raised (fig. 13-18). land, double the clearanceangle and grind a secondary land.

SIDE MILLING CUTTERS

The peripheral teeth ofa side milling cutter are ground in exactly thesame manner as the teethofaplainmillingcutter,with the exception that a plain toothrest blade is used. To sharpen the side teeth,mount the cutter on a stub arbor and clamp thearbor in a universal workhead. Thenmount a universal tooth rest holder ontothe workhead so that when the workhead is 28.431 tilted the tooth rest Figure 13.17. Changing clearance angle byswiveling the holder moves with it (fig.13-16). cutter in a vertical plane.

13-16 412 Chapter 13PRECISION GRINDING MACHINES

28.432 Figure 13-18.Changing the clearance angle by raising the grinding wheel.

STAGGERED TOOTH There is, however, a method for sharpening CUTTERS all of the cutter's teeth in one setting (see setup, fig. 13-9A). Staggered tooth milling cutters (fig. 13-19) 1. Mount the cutter on a mandrel held may be sharpened in exactly the same manner as between centers. plain milling cutters with helicalteeth (fig. 13-20). If you use this method, grind all of the teeth on one side of the cutter. They turn the cutter over and grind all of the teeth on the other side. 't ,4

k I

28.434 28.433 Figure 13-20.Tooth rest mounted on wheelhead in Figure13-19.Staggered-tooth sidemillingcutter grinding a helical-tooth cutter (Brown & Sharpe Mfg. (National Twist Drill). Co.).

13-17 41 3 MACHINERY REPAIRMAN 3 & 2

tooth rest. Continue alternatingteeth on each pass until you have sharpened all the teeth.

ANGULAR CUTTERS

To sharpen an angularcutter, mount the cutter on a stub arbor and mount the arbor ina universal workhead. Then swivel theworkhead on its base to the angle of the cutter. Ifthe cutter has helical teeth, mount the toothrest on 126.50 the wheelhead. But if the cutter Figure 13-21.Tooth rest blades for staggeredtooth has straight cutters. teeth, mount the tooth reston the table or on the workhead. To set the clearanceangle for both types of teeth,tilt the workhead the required number of degrees toward 2.Fasten the tooth rest holderto the or away wheelhead. from the grinding wheel. Thenuse a centering 3. gage to align the cutting edge ofone tooth Grind the tool rest bladeto the helix. parallel with the cutting face of angle of the cutter teethon each side of the the wheel. Take blade (fig. 13-21). a light cut to check your settings and make fine 4. adjustmentsuntilyouobtainthedesired Position the high point of thetooth rest clearance angle. blade in the center of thecutting face of the wheel. END MILLS 5.Align the wheelhead shaftcenterline, the footstock centers, and the highpoint of the A damaged end millmay be salvaged by tooth rest blade in thesame horizontal plane. cuttingoffthedamaged 6. portionwitha Raise or lower the wheelheadto give the cylindrical grinding attachment,as shown in desired clearance angle. figure 13-23. When salvaging 7.Rest an end mill in this thefaceofatooth onits manner, use a coolant if possibleto avoid corresponding side of the toothrest blade (fig. removing the temper at the 13-22). end of the cutter. The center of the end must berelieved in the 8. Move the cutting edgeof the tooth same way as the original cutter. across the face of the wheel. On thereturn cut, Generally, it will not be rest the next tooth on the opposite necessary to sharpen angle of the the peripheral teeth. If,however, the peripheral teeth must be ground,use the same procedure that you would use to sharpena plain milling cutter except for the method ofmounting the cutter. Mount the end millin a universal workhead(fig.13-24)insteadof between centers. You must remember thatwhenever you TOOTH grind the peripheral teeth of REST an end mill you BLADE change the size (diameter) ofthe cutter. You, therefore, must indicate that thecutter size has been changed. Either mark thenew size on the cutter or grind off the old sizeand leave the cutter unmarked. Use the following stepsto sharpen the end teeth: 28.435 Figure 13-22.Resting the face ofa tooth on its 1.Mount the mill ina universal workhead. corresponding side of the tooth rest blade. 2.Swivel the wheelhead to 89°.

13-18 414 Chapter 13PRECISION GRINDING MACHINES

m41' a

126.51X Figure 13-23.cutting off the damaged end of a helical end mill.

74' S'42,.

I

126.52X Figure 13-24.Grinding the peripheral teeth of in end mill.

13-1941 MACHINERY REPAIRMAN 3& 2 3.Bring the cutting edge of a tooth into clearance angle and grindallthe secondary the same horizontal planeas the wheelhead lands. spindle axis by usinga centering gage. Place the gage on top of the wheelhead and raise or lower On large diameter wheel end mills,it is often the wheelhead sufficientlyto place the blade of the gage on the tooth cutting a good idea to back off the faces of the teeth edge. This will at toward the center of thecutter, similar to the the same time align the cuttingedge with the centerline of the wheel. teeth of a face mill. An angleof about 3° is 4. sufficient, allowing a land of 3/16to 5/16 inch Lock the workhead spindle inplace to long. prevent the cutter from moving. 5. Clamp the tooth rest bladeonto the It is important thatyou use as much care workhead sothatits supporting edge rests when grinding thecorners of the teeth as when against the underside of the toothto be ground. grindingthefaceof the peripheralteeth; 6.Swivel the workhead downwardto the otherwise, the cutting edges will dullrapidly, desired clearance angle and clampit in position. and a poor finish will result. Thecorners of the At this point, makesure that the tooth next to teeth are usually chamfered 45°by swiveling the the one being ground will clearthe wheel. If it workhead or table andare left 1/6 to 1/8 inch does not, raise or lower thewheelhead until the wide. tooth does clear the wheel. .7. To sharpen the end teeth ofa shell end mill Unclamp the workheadspindle and (fig. 13-25), mount the cutter begin grinding the mill. on an arbor set in 8. a taper shank mill bushing. Then insertthe After you have ground all of theprimary bushing into the taper shank mill lands,tiltthe workhead to bushing sleeve the secondary held in the universal workhead.To obtain the

F.4',A444;

amla

126.53X Figure 13-2b.Grinding the endteeth of a shell end mill.

13-20 416 Chap ter 13 PRECISION GRINDING MACHINES desired clearance angle, swivel the workhead in the vertical plane and swivel it slightly in the horizontal plane to grind the teeth low in the center of the cutter. Turn the .cutter until one of the teeth is horizontal; then raise the wheel until that tooth can be ground without interference.

FORMED CUTTERS There are two methods commonly used to sharpenformedmillingcutters.Thefirst method,usingaformedcutter sharpening attachment, is by far the most convenient to use. The second method consists of setting up the cutter on a mandrel, grinding the backs of theteeth and then reversing the cutter to sharpen the cutting face. The involute gear cutter (fig. 13-26) will serve as an example. Since these cutters are form relieved, the only correct way to sharpen them is to grind the faces of the teeth. This type of cutter is ground radially on the cutting face after the backs of the teeth have been ground. Besure to grind the backs of the teeth. If the teeth are to be ground uniformly, they must all have the same thickness from the back to the cutting face.

To sharpen a formed cutter using the formed cuttersharpeningattachment,attachthe wheelhead shaft extension to the shaft and 28.436 mount a dish-shaped wheel on the extension. Figure 13-26.Involute gear cutter. With the wheelhead swiveled to 90°, clamp the attachment to the table with the pawl side of the attachment away from the wheel. Place the the table to move the cutter away from the cutter on the stud in the reverse position, so that wheel. Lift the cutter off the stud and turn it to the backs of the teeth can be ground. the next tooth. Be sure to hold the cutter The backs of the teeth must be in the same against the solid pawl with one hand while planeasthefaceof thewheel. This is grinding. accomplished by placing the centeringgage on top of the wheelhead and adjusting the head Due to the deformations set up in hardening, vertically until the cutter and the gage are about the amount ground off one tooth may be greater central. Then remove the gage. Adjust the saddle than the amount ground off the next tooth, but in or out and at the same time rotate the cutter after the backs of the teeth have been ground, (by hand) on the stud. Place the edge of the there will be a uniformity between the backs of pawl on the relief, behind the cutting face of the the teeth and the outside diameter. tooth being ground, and clamp in place by To sharpen the cutting faces of the teeth, tightening the locking knob. reverse the cutter on the stud and line up- the After grinding the back of the first tooth, cutting face of a tooth with the attachment index for grinding the next tooth by traversing centering gage. Loosen the pawl locking knob

13-21 MACHINERY REPAIRMAN 3& 2

and adjust the pawl to the back ofthe tooth. HONES AND HONING Then adjust the saddle to bring theface of the tooth in line with the face of the grinding wheel. In honing, the cutting is doneby abrasive Once this adjustment has been made,do not action. Honing may be used to readjust the saddle except to remove stock compensate for from a drilled, bored, reamed,or ground hole to wheel wear. After grindingone tooth, move the correct taper, out-of-roundness, saddle away from the wheel, index or bow (bell to the next mouthedbarrelshapeormisalignment). tooth, and grind. If, after all teethhave been Honing is also used to develop ground once, the teeth have not a highly smooth been ground finish while accurately controllingthe size of the enough, rotate the tooth face towardthe wheel hole. and make a second cut on each tooth. You may do cylindrical honingon a honing If a cutter has been initially providedwith a machine or on some other machine radial rake angle, this angle must tool by be retained or attaching the honing deviceto the machine the cutter will not cut thecorrect form. To spindle, or you may do it by hand. sharpen this type of cutter, line Regardless of up the point of the method you use, either thehone or the work one cutter tooth with the attachmentgage, must rotate, and the honing tool swivel the table to the degree of must move undercut, adjust back and forth along the axis ofrotation. the saddle to bring the face of thetooth in line with the face of the wheel, and grind. If a formed cutter sharpening attachment is PORTABLE HONING EQUIPMENT not available, formed cuttersmay be sharpened using a setup similar to that ofa plain milling cutter; between centers on The portable hone shown in figure13-27 is a mandrel. Using this similar to the type used inmost Navy machine method the setup for grindinga radial tooth shops. It is normally available in formed milling cutter and for grinding sizes ranging a tap are from 1 3/4 to 36 incheswith each hone set essentially the same. We willuse a tap in this being adjustable to example. cover a certain range within those sizes. The hone illustratedhas two honing stones and two soft metal guides. The Grinding a Tap stones and the guides advance outwardtogether to maintain afirmcutting To grind a tap, use the following actionduring honing. An steps: adjusting nut just above thestone and guide assembly is used to regulate thesize of the 1.Mount the wheelhead shaftextension and the dish wheel on the machine. honed bore. Accuracy to within0.0005 inch is possible when theproper operating procedures 2.True the wheel with the diamondtruing are observed. device. To use the portable hone, followthese basic 3.Line up the face of the wheel withthe steps: footstock centers. Placea straightedge across the face of the wheel and adjust the saddle toward 1. Clamp the hone shaft inthe drill press the wheelhead until the wheelface is centered. chuck. 4.Place the tap between centers. 2. Clamp the workpieceto the drill press 5. Fasten the tooth rest to thetable, with table. the blade against the back ofthe blade to be 3. ground. Put the hone intothe holeto be polished. Use honing compound 6.Adjust the tap to the wheel with as required. the 4. Turn on the drillpress and use the drill micrometer adjustment on the toolrest. 7. press feed handle to move the rotatinghone up Grindlhe tap. and down in the hole. To produce accurate results in grinding taps, When a lathe (verticalor horizontal) is used grind the backs of the teeth beforeyou grind the faces. to hone, the work can be mountedin a chuck or on a faceplate and rotated. The honingtool is

13-22 41s Chapter 13PRECISION GRINDING MACHINES

ADJUSTING NUT

STONE

28.437 Figure 13-V.Portable hone. held' in the tailstock with a chuck and moved reservoir, a workholding device, and a spindle to back and forth in the workpiece bore by the rotate and stroke the honing stones. Controls to tailstock spindle. adjust the rpm, rate of stroke, and the pressure On a milling machine or a horizontal boring feeding the stones to the desired size are usually mill the workpiece is mounted on the -table and standard. Some models have a zero setting dial the honing tool is mounted in the spindle. The indicator that lets you know when the desired hone is passed back and forth in the workpiece bore sizeis reached. This indicator must be bore by moving the machine table. preset with a gage that is the same size as the required size of the bore. Another method is to use a hand held power drill to rotate the hone in the workpiece. Move the rotating hone in and out of the hole by STONE SELECTION hand. Each of these methods requires that the The honing stone is made of grit, a bond, hone be allowed to self-align with the workpiece and air voids similar to a grinding wheel. The grit bore. To assistinthis,place one or two is the cutting edge of the tool. It must be tough universals between the hone shaft and the device enough to withstand the pressure needed to or spindle which will hold or drive the hone. make it penetrate the surface, but not so tough These universals and shaft extensions are usually that it cannot fracture and sharpen itself.The available from the hone manufacturer. bond must be strong enough to hold the grit, When honing large boxes, use a device that but not so strong that it rubs on the bore and attaches to the hone and lends support to the interferes with the cutting of the grit. Air voids stones and guides to ensure a rigid setup. in the structure of the stone aid the coolant or honing oil in clearing chips and dissipating heat.

STATIONARY HONING EQUIPMENT Honingstonesareavailableineither aluminum oxide grit for ferrous metals or silicon Stationary honing equipment is not used as carbide grit for nonferrous metals and glass..Grit often in the machine shop as the portable hone. sizes from 150 to 400 are available. If a large Con;tr often found in too many amount of metal must be removed, a coarsd grit ,o ate usually self-contained stone such as a 150-grit should be used to bring hones . honing oil pump and the base to within 0.0002 to 0.001 inch of the

13-23 449 MACHINERY REPAIRMAN 3 & 2

finish size. A finer grit stone shouldthen be used rotating and reciprocating motions to obtain a smooth finish. must be at an Specific odd ratio to each other. Thus,every part of the recommendationsforstone bore is covered beforeany grit repeats its path selectionisavailablefromthehone of travel. manufacturer. If a bore requires honingto correct taper or out-of-roundness, about twiceas much stock should be left for honing STONE REMOVAL as there is error in the bore. It is sometimes practicaland economical to perform two honing operations:(1) rough Honing does not change the axiallocation of a hole. The centerlin.. of the honing to remove stock and (2) finishhoning to honing tool developthedesiredfinish.As previously aligns itself with the centerline ofthe bore. mentioned, from 0.0002 to 0.001 Either the tool oil the inch should part floats to ensure that be left for finish honing. Ifa machined bore the tool and the base align.Floating enables the tool to exert equal must be heat treated, rough hone itbefore heat pressure on all sides of the treating to producean accurately sized, round, bore. and straight bore. After heat As the honing tool is stroked through treating, finish the hone to correct any minordistortion and to bore, the pressure of the gritsis greatest at the produce the desired finish. tight spots. Thus all taper andout-of-roundness Honing produces a crosshatch are taken out before any stock is removed finish. The from depth of cut dependsupon the abrasive, speed, the larger section of the bore.Also any bow is taken out. Since the honing pressure, and the coolant or honing oil used.To stones are rigid produce a finer finish,you can do one or all of throughout their length, theycannot follow a the following: buwthey bridge the low spotsand cut deeper on the high spots, tending to straightenout a 1. bow. Use a finer grit stone. 2.Increase the rotating speed. After you have honed out theinaccuracies, 3.Decrease the stroking speed. you must abrade every section of thebore equally. To ensure 4. Decrease the feedpressure. thatthishappens, the 5.Increase the coolant flow. CHAPTER 14

METAL BUILDUP

Metalbuildupisa rapid and effective haveincreasedtheuseofthermalspray method of applying practically any metal to a processes. Metal coatings are especially useful in base material with a spray gun to restore worn rebuilding worn shafts and other machine parts mechanical equipment, salvage mismachined or not subject to tensile stress, in hard surfacing otherwise defective parts, and protect metals where resistance to wear and erosion are desired, againstcorrosion. As comparedtooriginal and in protecting metal surfaces against heat and component replacement costs, metal buildup is a corrosion.Navalshipyards,Intermediate low cost, high quality method of restoration. Maintenance (IMA), and repair ships use thermal spray processes to coat metallic and nonmetallic As you advance in the MR rating you must surfaces with practically any metal, metal alloy, know how toprepare a surfacefor metal ceramic, or cermet that can be made in wire or buildup and be able to set up and operate the powder form. (Cermet is a strong alloy of a heat equipment used in the thermal spray systems resistant compound and a metal used especially and the contact electroplating process. In this for turbine blades.) chapter, we shalldiscuss the thermal spray systems and the contact electroplating process. In this chapter we shall discuss the wire Additional information on metalizing can be oxygen-fuelsprayprocess and the powder found in Mil Std1687(SH) Thermal Spray oxygen-fuel gas spray process with emphasis on Processandin NAVSHIPS 0919-000-6010, the latter. These are the two thermal spray Instructions for Metalizing Shafts or Similar processes you will most likely use as an MR3 or Objects. MR2.

APPROVED APPLICATIONS THERMAL SPRAY SYSTEMS

Therearefour differentthermal spray Thermal spray coatings have been approved processes:wireoxygen-fuelspray, by NAVSEA for several applications. Case by wire-consumableelectrodespray,plasma-arc case approval is not needed for use of thermal spray, and powder oxygen-fuel gas spray. In sprayingintheapplicationslistedbelow. general,all four processes perform the same Procedures usedfortheseapplicationsare basic function: They heat the wire or powder limited to those which have been approved by that will be applied to its melting point, atomize NAVSEA. the molten material with either high velocity gas or air, and propel it onto a previously prepared 1.Repair of seal (packing) areas of shafts surface. used in oil and freshwater systems to obtain original dimensions and finish. The rapid rate at which metal coatings can 2.Repair of bearings' interference fit areas be sprayed and the portability of the equipment of shafts to restore original dimensions and

14-1 421 MACHINERY REPAIRMAN3 & 2 finish (except formotord-generators where chrome plating is permissible). operator will be responsiblefor setting up the spraying equipment accordingto the parameters (gun-to-workdistance,air, 3.Buildup of pump shaftwear ring sleeves fuelgas,etc.) to original dimensions. required by the sprayingprocedure. An operator failing theinitial qualification 4.Repair of miscellaneousstatic fit areas, tests may be permittedone retest for each type such as thoseon electric motor end bells, to of test that failed tomeet the requirements. restoreoriginaldimensions,finishand alignment. Operators meeting therequirements for the performance tests will becertified to perform manual spraying withthe coating system and SAFETY PRECAUTIONS spray process used in qualificationtesting. Certification of the operatorwill be retained unless 6 months haveelapsed since the last Metalizing melts metal inwire form in a of the thermal use flame and atomizes it byajet of compressed air spray process. Operators whose into a finespray. The metal particles certification has lapsedmay be requalified by may be satisfactorily completing inhaled easily byanyone present. Personnel the qu'alification tests. usingmetalizing Complete informationregardli igcertification equipmentmustwear can be found in MIL-STD-1681. respirators that have beenapproved for this kind of work. WIRE OXYGEN SPRAY You must wear safetyglasses or face shield and proper protectiveclothing at all times during thermal spraying operations. The wireoxygen-fuelsprayprocessis suitable for allpurpose use. It Offers variable, Cleaningsolventsaretoxicand controlled wire feed hazardous rate within theranges toyour health. Use only ina required forall commonly used well-ventilated area. metallizing wires, and it can be usedin both hand held and machine mountedapplications., Figure14-1 Warning signs must beposted near the shows a typical installation. operation to warn personnel. The Type 12E FlameSpray Gun (fig. 14-2) can spray metalizing wires, suchas aluminum, Adhere strictly to the safetyprecautions zinc, copper, Monel, noted in the WeldingHandbook, Sixth Edition, nickel, etc., in wire sizes Section 1 Chapter 9, ranging from 3/16 inchdown to 20 gage using published by the American acetylene, propane, natural WeldingSociety,andthemanufacturer's gas, manufactured handbook. gas, or MPS as the fuelgas. The wire is drawn through the gun andnozzle by a pair of wire feed . e rolls, powered bya self-contained QUALIFICATION OF PERSONNEL compressed air turbine.At the nozzle, the wire iscontinually melted inan oxygen/fuel gas flame. Then, a controlledstream of compressed Thermal air blasts the moltentip of the wire, producing sprayoperationsmustbe fine metal spray. a performed only by qualifiedpersonnel. The Systems of this typeare commonlyusedtosprayaluminum operator must prepare testspecimens for visual, coatings wire microscopic, bend and bond forshipboardcorrosioncontrol tests using qualified applications such procedures developed forthe particular coating as steam valves, stanchions, and thermal exhaust manifolds, deckmachinery, equipment spray process. In addition, the foundation, etc.

14-2 404.40 Chapter 14METAL BUILDUP

ALSO SUITABLE FOR GAS COMBUSTION POWER SPRAYING GUN

AIR LINE GAS FLOWLINE AIRFLOW METER

GAS COMBUSTION WIRE SPRAYING WIRE

FROM COMPRESSOR

LINE PRESSURE LINE PRESSURE REGULATORS

MAIN AIR DRYING AIR AIR ACETYLENE OXYGEN UNIT RECEIVER FILTER PRESSURE CONTROL 28.440 Figure 14-1.Typical installation for combustion gas spraying.

POWER CANISTER

POWDER FLOW CONTROL VALVE OXYGEN

MR CAP BODY FAIR

TPIGGER ACETYLENE 28.441 Figure 14-2.Type 12E spray gun. GAS VALVE HANDLE

POWDER OXYGEN-FUEL SPRAY

Figure 14-3 shows a powder spray gun. The 28.442 powder feeds by gravity through a metering Figure 14-3.Gravity feed oxygen-fuel powderspray valve and is drawn at reduced pressure intoan gun.

14-34:23 MACHINERY REPAIRMAN3 & 2

aspiratorchamber. From the chamberthe The type of roughening powder is propelled throughthe flame where it treatment used and the melts and then deposits degree of roughness will dependon the type and on the work in the form thickness of coating to be of a coating. The Type 5PThermo Spray Gun applied and on the anticipated conditions ofservice. Frequently, willspraymetal,ceramic,cermetand exothermic powders. preparation is inadequate simplybecause proper preparation is not convenientor the necessary Exothermic coatings compositesare those that produce equipment may be lacking.But even the best an exothermic (heat evolved) and most elaborate surface reactionderivedfromtheir preparation is the chemical least costly part of the job.The operator should composition. These coatingmaterials include see to it that the required equipment METCO 402 and 405 wiresand 442, 444, 445, is available 447, 450 powders. When and that the job of preparingthe surface is the composites reacha carefully and thoroughly done. certain temperaturein the spray gun flame, nickel and aluminum, for example;react to form Cleaning Methods nickel aluminide and evolvea great deal of heat. The extra heat provided to the molten particles To ensure a good bond by the exothermic reaction,coupled with the between the sprayed highparticle `coating and the base materialto which it is velocity of the thermalspray applied, be sure the process,accountsforthe areas to be coated and the self-bonding --jacent areas are free fromoil, grease, water, characteristics of the coatingand its exceptional .At, and other foreign matter strength, both perpendicularand parallel to the which may substrate (base). contaminate the coating. Exothermic materialsare often referred to as `solvent Cleaning one-step coatings. They produceself-bondini,, one-stepbuildupcoatingsthatcombine Prior to any blastingor spraying, clean with metallurgical bonding with goodwear resistance. solvent all surfaces that They also eliminate the needfor separate bond have come in conta:t and buildup coatings. 'ith any oil orgrease. (Vapor degreasing is preferred, but you may The gravity fedoxygen fuel powder spray use solvent washing.) gun must be used in When using solvent, bevery careful to prevent a horizontal position. any detrimental attacks on the base Deposit efficienciesare very high, almost as high material; do as 100% in some cases. Only NOT leave any residue filmon the base surfaces. a minute amount of METCO-Solvent Trichloroethane the powder is lost bybeing blown awayor 0-T-620 or consumed in the flame. Toluene ITT-548are suitable solvent cleaners. Because of the flammableand toxic nature of mostsolvents,you MUST followproper PREPARING THE SURFACE precautions during solventcleaning. You must also be very careful toprotect any parts that may be attacked by the solvents. Surface preparation isa very important step inthemetallizing process. An improperly Abrasive Cleaning prepared surface maycause failure of the part underoperatingconditions.Preparingthe surface consists of three distinct You can use abrasiveblasting to remove operations: (I) heavy or insoluble deposits.Do not use the cleaning,(2)undercutting, and (3)surface roughening. abrasive blasting equipmentyou use for general We cannot overemphasize cleaningoperationsforsurfaceroughening the importance of operations. proper surface preparation. Althoughit is often the most ...deal part of the totaljob, it is Heat Cleaning frequently given the leastconsideration. Even in the case of coatings that are to be fused, very Solvent clean thorough preparation issometimes necessary. porous materials that have been contaminated withgrease or oil and then

14-4 Chapter 14METAL BUILDUP heat them for 4 hours to char and drive out the service, the amount of wear expected in service, foreign materials from the pores. Heat steel the depth of metal loss, the remaining thickness castingsat 550°F (288°C) maximum; heat of the load carrying member, and The limits of aluminum castings, except age hardening alloys, the particular coating. In general, the minimum at 300°F (149°C) maximum. In thin sections, specified depth of undercutting should be at use lower temperatures to minimize warpage. leastequaltothe recommended minimum thickness for the particular coating, plus the UNDERCUTTING wear or corrosion tolerance for the application. Undercutting and surface roughening reduce the Toobtain A satisfactorythicknessof effective structural cross section of the part to' metalized deposit on the finished job, usually be metalized. Also, sharp grooves and re-entrant you need to undercut the surface to be built up. angles may produce stress risers. When preparing (See fig.14-4.) 'Undercutting must be a dry for thermal spraying, carefully examine froma machining operation, as any cutting lubricants design standpoint all parts subjected in service to or coolants used will contaminate the surface of high stresses, shock loads, or critical applications the workpiece. When building up shafts, be todeterminethatadequatestrengthis extremely careful to ensure that the undercut maintained in the structure. Metal spray deposits section is concentric to the original axis of the cannot be depended upon torestore such shaft. The length of the undercut should extend qualities astensilestrength or resistance to beyond both ends of the sleeve or bearing or the fatigue stress. NOTE: Shot peening may be used limits of the carbon or labyrinth ring, or the inapplicationsthatrequirehighfatigue packing gland in which the shaft will operate. resistance of the coating system. Shot peening is However, you must be careful not to remove done by impinging a high-velocity stream of any fillets at points where the shaft section metal or glass particles suspended in compressed diameter changes. The ends of the undercut air onto Ahe metal substrate. Shot peening is should be straight or chamfered at 45° to the normally performed by dry blasting with cast base metal. steel shot with a hardness of Rockwell C 40 to The depth to which a shaft should be 50. Steel shot must not be used on aluminumor undercut is determined by a number of factors. stainless steel; glass beads should be used for Some of these factors include the severity of aluminumorstainlesssteelalloys.When

THICKNESS OF COAT UNDERCUT s MINIMUM COAT THICKNESS EQUALS UNDERCUT FINISHING PLUS WEAR ALLOWANCE PLUS FINISHING ALLOWANCE ALLOWANCE FINISHED T ICKNESS r wegoossemsegu -:....,,,

remowtwmwagrm---- ORIGINAL UNDERCUT SURFACE BUILD UP FINISHED DIAMETER PREPARATION T ORIGINAL DIAMETER STEP I STEP 2 STEP 3 STEP 4

126.1 Figure 14-4.Major stops in restoration of dimensions with thermalspray.

14-5 4t)r- MACHINERY REPAIRMAN 3 & 2

required, shot peening is performed following should not be used for any otherpurpose. Use machining and before abrasive blasting. the following ranges of grit sizeas a guide in selecting the desired grit. SURFACE ROUGHENING GRIT SIZE GRIT SIZE MESH USE Nfter undercuttingtheshaft, you must r...ghen the undercut section to providea bond for the metal spray. During undercuttingand roughening, do NOT use a lubricantor coolant. Coarse (-10 to +30) Use where the coating Keep the surface clean and dry. Even touching thickness will be greater the surface with your hands would contaminate than 0.010", and where it.If,for any reason,the surface becomes theroughestblasted contaminated, you must thoroughly clean and surface is required degreaseit.Thecleanlinessand roughness greatly affect the strength of the bondbetween Medium (-14 to +40) Use where the coating the base metal and the sprayed coating.You thicknesswill be less must always carefully control cleanlinessto than 0.010", and where ensure adequate bond strength for the service to theroughestblasted which the part will be subjected. Two methods surface is not required of surface roughening are abrasive blasting and or cannot be tolerated macroroughening for restoration of dimensions greaterthan 1/2inchwhereexothermic Fine (-30 to +80) Use under thin coatings materials cannot be used. which will be used as sprayedorfinished Abrasive Blasting for lightlybybrush Surface Preparation blasting

Prior to thermal srraying, conditionthe General Notes on Blasting surfaces to be coated by abrasive blasting.The required amount of surface roughness is related to the configuration of the part. Wherepart Clean, dry air is essential. Traces of oil in the configuration permits, a roughness of 200-300 airwhich cannot be readily detraedcan microinchesis desired.Blastingpressureis seriously affect the bond. A goodtest is to put a normally 60 to 80 poundsper square inch (psi) drop of cleaning solvent, forsuction or equivalent fast typeequipmentandthe drying solvent, on the blasted surface.A distinct nozzle-to-work distance is about 3 to 6 inches. dark ring after the solvent dries usually indicates Blasting must not be so severeas to distort the oil in the air. part. When distortion can occur, suchas with Keep the blast angle within 10°or 15° from thin walled sheet metal parts, reduce roughening the perpendicular. Where access to the surfaceis as necessary to a minimum surface roughness of difficult and you must blast from 63 a steeper microinchesandregulatetheblasting angle,applythesprayfrom pressure as necessary. thesame approximate angle. If you blast atan angle from Abrasive blasting particles used for surface one direction and spray from an angle in the preparation may be either angular nonmetallic other direction, the bond strengthmay be close grit (e.g. aluminum oxide) or angular chillediron to zero. grit. To prevent rusting, the abrasive particles Thorough blasting is important. It isgood cannot contain any feldspar or other mineral practice to blast until the surfaceappears fully constituents which tend to break down and blasted, that is, until further blastingproduces remain on the surface invisiblequantities. no visible change, and then to blast further for Chilled iron grit must be kept dry during a storage short period. In other words, blastevery piece and use. Grit designated for coating preparation about 150% as long as appears to benecessary. 14-6 11111s. Chapter 14METAL BUILDUP Masking for Grit Blasting primary and secondary pressures, and power output) contained in the approved procedure for All areas of a component that are not to be the material being sprayed. grit blasted must be covered and masked to You muststartthespraying operation preventdamageorcontamination bythe within 2 hours after completing the preparation abrasive blasting media and debris. Rebound grit of the surface. If more than 15 minutes, but not from the walls of the blast room or blast cabinet over 2 hours is expected to elapse between the may scratch and damage areas of the work preparation of the surface and the spraying which are not to be blasted unless they are operation, or when the part must be removed to adequately covered. Masking for blasting may be another location, you must protect the prepared an expensive part of the operation and this surface from oxidation,contamination, and should be taken into account when selecting the handling and fingermarks. Clean paper (free of masking method. Following abrasive blasting, newsprint)willusuallyprovideadequate remove anmasking material that is unsuitable protection. as a masking material for the thermal spray Whenever possible (or practical) preheat the process and replace it with masking material workto200°-225°Ftoeliminatesurface suitable for thermal spraying. moisture. (Higher preheats may be required on a Metal masks and blasting jigs are commonly case basis for specific substrates/coatings which developed for this purpose. You can sometimes may develop defects due to thickness of coating, fit the work into a jig in such a way that the part thermal gradients, or differences in coefficients to be blasted is the only part exposed. Where of expansion.) Take temperature readings witha necessary, you must use additional covers or contact pyrometer. Do NOT use temperature metal masks. One great disadvantage in using sticks or similar devices in thermal sprayarea. If metal for masking in blasting, however, is the you preheat with a gas flame, do not apply the metal mask itself which blasts away rapidly and flames directly onto the area to be sprayed to must be replaced frequently. avoidpossiblesurfaceoxidationand Rubber has provedtobe much more contamination from carbon deposits. successful in masking for blasting purposes, and To safeguard against the possibility of cracks you should use it wherever possible. Sometimes that may occur in the sprayed deposit due to it is quite practical to construct whole jigs from difference in the expansion of the substrate and blocks of rubber rather than from metal. Rubber the sprayed metal, do not spray on substrates or aluminum masking tape is very satisfactory with a temperature' below 60°F. for all operations where hand masking can be Interrupt the spraying operation only to used- conomically. Since rubber is not cut by measure thickness or temperature, to change tife blting operation, you can use rubber jigs spraying material from bond or undercoat to almosindefinitely. You can use thin rubber finish coat, or to permit cooling to prevent tape/for heavy blasting protection. overheating. During spraying, do not allow the temperature of the work to exceed 350°F or the Macroroughening tempering/aging temperature of the substrate, whichever is lower. For cooling usea blast of Macrorougheningisalatheoperation clean air, carbon dioxide, or other suitable gas performed on bearing areas of shafts or similar introduced near but not directly upon thearea surfaces.Itconsistsof cuttinganarrow, being sprayed. low-pitch,shallow groove or threadinthe In general, keep the direction of the metal surface. spray as close as possible to a 90° angle with the surface being coated and never less than 45°. APPLICATION OF COATING Apply the coating in multiple passes of 0.005 ±0.001 inch for wire spray and 0.003 ±0.001 Spray the component using the parameters inch for powder spray. Cover the entire prepared (e.g. gun-to-work distance, rotational or linear surface with a pass of spray before proceeding to speed of gun to work piece, air,fuel, gas, the next pass.

14-7 MACHINERY REPAIRMAN 3 & 2

When you use the macrorougheningmethod of surface preparation, apply as thermal-spraying masking materials. Tapes at least the first used for spray masking must bedesigned for four layers of deposited metal in eachdirection high-temperature use. Masking materials with the spraying stream directed at 45° must to the not cause corrosion or contaminationof the perpendicular, alternately from leftto right, in sprayed coatings. order to deposit metal onto eachface of the thread. Then complete the work byspraying at More generally, however, masking right angles to the surface. tape and masking compoundareusedfor masking For cylindrical parts, direct thespray stream at the axis at all materials to be sprayed. Usea pressure sensitive times. Coat the part ata masking tape which is designedto withstand the rotational speed of 40 to 100 surfacefeet per usual spray temperatures. minute or as otherwise specified. When a machined finish is required, spray a Masking compound (METCOor equivalent) minimum of 0.005 inch thicknessof sprayed is designed for masking where metal in excess of that required a liquid masking for finished material is more convenient. Itis a water soluble dimensions onthesurface toprovidefor material which can be brushedonto any surface machining or grinding. For shafts,make the topreventadhesion measurements on the radius. Follow the of sprayedmaterial. coating Approved masking compound willnot run or manufacturer's recommendations. bleed at the edges. Allow the work to cool normallyto room temperature after spraying. If it isnecessary to Masking compoundmay also be used to cool the work more quickly,direct an air blast protect the spray booths and otherequipment against it. Do not quench witha spray of water which is subject to overspray, or other liquid. such as rotating spindles, chucks, lathes, and thelike. When used Application of Sealant for this purpose, the surfaces shouldbe cleaned on a regular schedule and the compoundshould be re-applied, since it will eventuallydry out and To prevent corrosive attackor fluid leakage, the sprayed material will sprayed coatings must be treated then stick tc the with a sealant. substrate.For instanceswhen holes, The particular sealant selectedwill depend upon slots, the keyways, or other types ofrecesses cannot be maximumuse temperatureofthe protected by tapes or shields, inserts component andthe purpose of sealing the of carbon or metal calk or rubber should be used.These coatings. The sealant is applied afterspraying inserts are installed before abrasive andbeforefinishmachining.For blasting and severe spraying, left in place throughoutthe thermal applications, a sealant should beapplied again, following finish machining. spray operation, and removed after completion of surface finishing priorto the final sealer Sealants used in thermalspray processes may be of the following types: application. SURFACE FINISHING 1.Paraffin wax 2.Resins a. Air dried The 'structure of sprayed metaldeposits is granular rather than homogeneous. b. Baked (heat cured) In spraying, c. Pressurized the minute particles of metalstrike the surface at high velocity, flatten out,and build up on d. Vacuum impregnated eachother. 3.Inorganic Thisstructure,which byits relativelylowcoefficientoffrictionand Masking for Spraying oil-retaining qualities makes sprayedmetal ideal for all bearing surfaces,creates a problem in You finishing. Experimentation andresearch indicate canusetapes,liquid-masking that with understanding and compounds, silicone rubber,or metal shielding appreciation of the characteristics of sprayed metal,machining and 14-8 428 Chapter 14METAL BUILDUP

grinding can be done in the toolroom or on the soft substrates, the finishing operations must be production line with less trouble than is caused done in a way to avoid loads on the coatings by many alloy materials in solid or wrought that could seriously deflect it. form. A machinist unfamiliar with sprayed metal Requirements will grind the tool bit and set it according to past experience on similar metal in its solid or Thermal sprayed coatings are sufficiently wrought form. As a result, crumbly chips similar different than the same material in wrought to those from cast iron will occur regardless of form that different grinding wheel and finishing the metal or the tool setting, and the surface will toolrecommendationsarealmostalways appearfullof"pin ricks" anddecidedly required. Therefore, tools and wheels should not porous. bechosen on experience with theparent material in wrought or cast form. Selection of A grinding wheel o erator will tend to use the finishing method depends on the type, the grain and grade wheel used on thesame material in wrought form. Regardless of the hardness, and thickness of the coating and the manner in which the operator dresses the wheel, finish desired. Softer coatings are often finished itwill by machining with a carbide tool, using speeds load up immediately and produce a and feeds for cast iron. Harder coating materials spiralled and discolored surface. If the operator continues and attempts to remove stock with a are generally finished by grinding. loaded or glazed wheel, surface checks that Wet grinding is usually recommendedover cannot be removed -Willappear.Sufficient dry grinding if the proper wheel is used. Wheels working data for both machining and grinding with coarse grain and low bond strengthare used have been establishedto permit production to grind sprayed coatings to prevent loading the finishing of all of the commercially used metals wheel. When a coolant is used, it should contain that have been developed for thermal spraying. a rust inhibitor, and it must be kept clean and Naturally, some finish better than others, but free of foreign matter. The grinding wheel must commercialfinisheswithincommercial not remain immersed in the coolant because it tolerances can and are being obtained on all will become unbalanced due to the absorption thermal spray alloys. of moisture. Because of the possibility of plucking out Thecoatingmanufacturer'sfinishing individualparticlesduringthefinishing recommendationsmustbeconsultedand operation, thefinishing parameters are most followed in selecting the finishing technique, important with sprayed coatings than with solid including the proper tool, feeds and speeds. materials.Withmanysprayedmaterials, Masking materials should be removed prior maintaininggrindingwheelsharpness,for to surface finishing. Finishing dimensions areas instance, and adhering to proper feeds and required by specification or drawing. speeds may be quite critical. Most applications Where finishing difficulties do arise even forsprayedmaterialsconsistoffairly thoughproperfinishingtechniqueswere thin-sprayed coatings over a substrate. Grinding followed, the spraying operation itself should be andfinishingoperationsshouldtakethis reviewed. It is quite obvious that if partic:es structure into account and avoid overheating the pluck out, for instance, the faultmay not be in coatingsorseriouslydeflectingthem. For the grinding but rather in substandard coatings. instance, if the coating material is a refractory Excessive moisture or oil in the air supply during material with low heat conductivity, there is the spraying operation can cause this trouble. some danger of developing hot spots during Maintainingproper gun-to-work distancein grinding. Machinists who are accustomed to accordance with the instruction manuals and grinding metals should be cautioned to grind spraying at the proper angle to the substrate slowly enough and apply sufficient coolant to surface are typical parameters which may affect avoid local overheating of such materials. Where the structure of the coating adversely and show thin coatings have been applied over relatively up as finishing difficulties.

14-9

Aw MACHINERY REPAIRMAN 3 &2 Machining becauseitrequiresspecialattention during machining. Thesprayedcoatingstreamhasan appreciable area (approximately '8 to 1/2 inch) The buildup at the shoulderusually has a and, therefore, the sprayedcing cannot be ragged edge and, if the tool is set terminated sharply at the end of to "hog it off", the undercut the sprayed material will crack offin chucks, section. At the end of the undercutsection (at possibly starting a crack which will the shoulders in thecase of a shaft), the coating penetrate the main section of the coating. Toavoid this will build up on top of thesurface adjacent to trouble, it is good practice to the underctit justas thick as in the undercut. If remove the ragged the undertht is 1/8 inch, edge by machining it separately, witha series of then something over fairly thin cuts, until the surfaceis nearly down 1/8 inch of sprayed materialwill be built up at to the shoulder before proceeding the shoulder. This buildup to take the at the shoulder of the full cut across the entiresurface. (See figure undercutisemphasizedinthisdiscussion 14-5.)

For Steps 1 and 2, use same RPMas for preheat, with slow feed and light inbred. Ilse tungsten carbide tool bit.

ENDS OF COATING TEND TO LIFT FROM MASKED ARIA. CROSS SECTION OF SPRAYEDCOATING.

\0.1. 46° 4411 \DIRECTION OF FEED. I, FIND HIGH SPOT OF COATING. 2. HANDFEED TOOL TO CUT CONTINUOUS OR STEPPED CHAMFER, BOTH ENDS FLASH WILL BREAK OFF.

COATING AFTER STEP 2. COATING AFTER STEP 5. /04117AIIIMAYANPAA

3. MACHINE OFF AREAS MARKED ',6*. 4. MACHINE TO REQUIRED DIAMETER, USE FEED TOOL FROM CENTER TO OUTSIDE. SPEEDS AND FEEDS FOR CAST IRON. INF'EED NOT TD EXCEED .010" PER PASS KEEP TOOL BIT SHARP.

S. MACHINE DRY.

6. LEAVE THE PIECE IN THELATHE UNTIL EDGES OF COATING ARE FINISHED.

28.443 Figura 14.5. Finishing machining ofa thermal spray posting.

14-10 ilj1) Chapter 14METAL BUILDUP

A general guide to finishing is to avoid followed since they do not apply to machining applying pressure in directions that tend to lift sprayed. materials. For instance, when machining the coating from the workpiece. Inmany cases, sprayed materials, it is never necessaryto take a a sprayed coating is subject to more stress in cut deeper than about 0.025". The side cutting finishing than it is in service. The procedures angle (see figure 14-6) is not important since described the aboveminimizethemachining cutting is done by the tool on the radiusat the stresses. nose of the tool. No back rake is required but it may be as much as 8°. Machining sprayed metal is not difficult. A tungsten carbide tool bit, sharpened forcast iron, will be satisfactory. The sprayedcoating Grinding contains hard oxides. High work speed, slow traverse and light infeed are required. When itis necessary to hold dimension to tight tolerance, tool Wherever the ground surface is to be used bit wear must be taken intoaccount. for a journal or bearing surfaceitis most Cemented carbide tools have been foundmore important that the final surface is clean andnot satisfactory than softer tools for machiningmost contaminated with grinding abrasive. While such sprayed metals. Even the softer sprayed metals surfaces can be cleaned by scrubbing after which can easily be cut with high-speedsteel grinding, it is often much tools, have an abrasive action more satisfactory to on the tool tip. seal the surface prior to grinding. Sealers,such as Carbidetoolsarenecessary for the harder METCO-SEAL AP and METCO 185 Sealer,have materials where machining is to be done. been developed for thispurpose. The use of sealer before grinding prevents contamination of Figure14-6 illustratespropertool the pores of the sprayed coating andalso helps configuration for machining sprayed materials. to provide a cleanly cut ground surface The usual rules that apply to the instead use of carbide of a surface with the particles smearedor drawn tools for heavy machining work shouldnot be into feathers.

END COATING SIDE NOSE RADIUS e r l O RAKE ANGLE r

7I7 IIRELRELIEF 13 r. ANGLE SIDE A r EDGE ANGLE

BACK RAKE ANGLE 8° MAX.

16o .

B 94 NOSE RADIUSh i.

0° BACK RAKE ANGLE END CUTTING EDGE ANGLE

C +I

28.444 Figure 14-8.Cutting tool angle for machining thermalspray-metal coating. 14-11131 MACHINERY REPAIRMAN 3 & 2 salI o smosismIr

Heavy grinding equipment with carefully retainabrasivesonthesurfacethansolid trued concentric wheels should always be used. materials. As mentioned earlier, sealing priorto (Seefig.14-7.) Pounding from an eccentric grinding will ensure clean final surfaces. wheel or vibration due to theuse of equipment that is too light for the job will damage the Figures 14-8, 14-9, and 14-10 illustrate the coatings or produce a poor finish. proper techniques for finishing keyways, holes Wet-grindingisrecommendedwhenever and other openings, and the ends of coatings. suitable equipment is available. Whenproper equipment is used no special difficulties arise in grindingsprayedmaterialsas compared to CONTACT ELECTROPLATING grinding these same materials in other forms. Of course, attention should be given to the special Contactelectroplating(brush-on)isa problems resulting from the structure of sprayed method of depositing metal from concentrated materialsas discussedearlier.It should be electrolytesolutionswithouttheuseof remembered, however, that sprayed materials immersion tanks. The solution is held inan are not the same materials structurally as those absorbent material attached toan inert portable in solid form and that different wheels, feed, electrode (anode) of a d.c.power pack. The speeds, etc. should be used,in accordancewith cathode lead of the power pack is connectedto the coating manufacturer's recommendations. thework piecetoprovidetheground, The softer sprayed materials, particularly the completing the plating circuit. Electroplating sprayed metals, tend to "loadra wheel. Wheels deposits metal by contact of theanode with the withrelatively coarsegrainand low bond work area. Constant motion between theanode strength are necessary for such materialsso that and the work is required to produce highquality the wheel will break down before loading. uniform deposits. Groundsurfacesshouldbe thoroughly cleaned after grinding whenever the surface is to Contact electroplating (also referred toas be used for a journal surfaceor a mating contact plating) can be used effectivelyon small machineelementpart.Thisprocedureis to medium sizeareas to perform the same emphasized because the porous structureof functions .as bath plating; for example,corrosion most sprayed coatings are more inclinedto protection,wearresistance,lowerelectrical contact resistance, repair of wornor damaged machineparts,etc.Thisprocessisnot recommended to replace bath plating. However, there are some advantages which makecontact electroplatingsuperiorinsomefieldsof application:

The equipment is portable; platingcan often be done at the job site.

It can reduce the amount of maskingand disassembly required.

It permits plating of smallareas of large assembled components or parts too largefor available plating tanks.

28.445 By plating to the required thickness,it Figure 14.7. Lathe grinder for dry grinding ofthermal can often eliminate finish machiningor grinding spray coating. of the plated surface.

14-12 4 32 Chapter 14METAL BUILDUP

1. FINISH COATING TO REQUIRED DIAMETER.

2. FILE OR GRIND CHAMFER ON KEYWAY THROUGH EDGE OF COATING TO BASE METAL.

.4% When filing or grinding, v COATING always work in direction COATING which pushes the coating 130 130 against the part.

Base Bose WRONG RIGHT

3. FINISH CHAMFER AS SHOWN BELOW. I. REMOVE SPRAYED METAL. FROM SIDES AND BOTTOM OF KEYWAY WITH CHISEL OR SCREWDRIVER. BREAK SHARP CORNERS

BASE METAL ABOUT 60° MUST SHOW

Sprayed metal is brittle.It is important to relieve the edges of the coating around a keyway so that when the part is put bock in service, the key cannot bear on the coating edge and break pieces out of it.

28.448 Figure 14.8. Finishing keyways.

Damaged or defective area of existing POWER PACK plating can be touched ur, instead of complete stripping and replating of the entire part. Contact plating power packs are available in direct current output ranges of 0-15amperes at Althoughthecontactelectroplating 0-20 volts to 0-150 amperes at 0-40 volts. These equipmentpower pack, plating tools, solutions, power packs operate on 115- or 230-volt 60-Hz plating tool coveringsare discussed in detail single- or three-phase a.c. input. throughout this chapter, the following sections contain brief descriptions which you need at this The intermediate sizes, 25 to 100ampere point. maximum output, are most commonly used.

14-13 433 MACHINERY REPAIRMAN 3 & 2

1,4. FINISH COATING TD REQUIRED DIMENSION.

2. FILE OR GRIND CHAMFER THROUGH EDGEOF COATING TO BASE METAL. GRINDING FILING

PRESSURE PRESSURE

SHAFT WITH BORE

USE BALL POINT

3. FINISH CHAMFER. 4. CLEAN ALL LOOSELY ATTACHED PARTICLES OUT OF BORE. BREAK SHARP CORNERS

BASE METAL ABOUT 60° COATING MUST SHOW

Bose BREAK SHARP REMOVE CORNERS OVERSPRAY WITH SCRAPER OR When ground with ball point, SCREWDRIVER this surface will not be flat. This is satisfactory.

The edges of the coating must be relieved around oil holes, slotsor other openings in the part, so that there is no possibility of pieces of sprayed metal breakingoff and getting between matingsurfaces. CAUTION: Clean the metallized piece thoroughly before r ling it back service. Any loose particles of sprayed metalmight cause trouble.

28.447 Figure 14-9.Finishing holes and otheropenings.

The units in this range are portable, weighing Power packs are traz:-.norl.ill: less than 150 lbs, yetcan provide the required through both a 25-inch diameter op,! .sing!t71: '/0 X 15-inch power for most shipboard and shop typework. rectangular opening. A unitinthe 60- to100-ampere rangeis recommendedasbasic contact plating shop PLATING TOOLS equipment. Even though subsequentworkload demand may require supplementing itwith Contact platingtools consist (4 smaller or larger units,a unit of this size will stylus lundlewith n conductivecore, mich is always re.nain useful. Thereare units available insulated for up to 200 amperes. jnerators:. -Pty, and ani-,sohlble anode normally of WO qualitygraph:i.l. Since

14.14 Chapter 14METAL BUILDUP

A. COATING IN MIDDLE OF SHAFT OR BORE

1. IF COATING FINISHES FLUSH AND SMOOTH, NO FURTHERWORK IS REQUIRED.

2.IF COATING FINISHES ABOVE SURFACE OF PART, CHAMFEREACH END AT ABOUT 45°.

RIGHT WRONG B. COATING AT END OF SHAFT OR BORE

1.IF COATING FINISHES FLUSH AND SMOOTH, NO FURTHERWORK IS REQUIRED.

2.IF COATING FINISHES ABOVE SURFACE OF PART, CHAMFER END AT ABOUT4V.

BREAK SHAFP CORNERS

CHAMFER

RIGHT WRONG

3.IF NO SHOULDER, CHAMFER AT ABOUT 4V.

BREAK SHARP 'CORNERS

RIGHT WRONG

The ends of the coating must be finished offso that there is no load on any edge of the sprayed coating when the part is put back inservice.

28.448 Figure 14.10. Finishing unds of coating.

considerable heat is generated during plating made of 90% platinum and 10% iridiummaterial operations there must bea means of cooling the are recommended. plating tool. The handles of plating toolshave The removable anodes cooling fins to dissipate heat. In are available from the some cases, equipment manufacturers ina wide range of largetools may requirethe use of plating standard sizes and three basic shapes: solution or water as a cooling medium. cylindrical Graphite OT convex forplatinginsidediameters; anodes are brittle and are not practicalfor use in concavefor outside diameters; and,flat or locations where a very small diameteranode is spatula shaped. required. For plating holes less than 1/2 inch in Graphite material may also be purchasedfor diameter, or narrow slots and keyways,anodes manufacturing special tools. MACHINERY REPAIRMAN 3& 2 SOLUTIONS qualify the operator must showproficiency in the contact platingprocess which includes the The solutions used in contact platinginclude following: preparatory solutions for cleaning and activating the surface to be plated, platingsolutions for (a) Preparation of metalsurface for depositing pure or alloy metals, andstripping contact plating solutions for removing defective plating:These (b) Selectionoftheproper power solutions are manufactured and soldby the settings, tools and solution process equipment manufacturers. Solutions of (c) Proper masking technique any trade name can be used if the deposits meet (d) Proper plating technique the applicable plating specificationand if they (e) Calculation of platingthickness arequalifiedby proceduretests.However, (I) Proper surface finishingtechnique plating and preparatory solutions of different 2.Successfully plate mock-ups, manufacturers must not be intermixedor simulating substituted in a plating procedure. typical plating work requiredat the facility, to For plating operations, solution the specified qualityrequirements and thickness is either range indicated in NAVSHIPS 0919-000-6010. poured into shallow glassor porcelain dishes or beakersfor dipping or intoa pump for Completion of an approved trainingcourse dispensing through solution-fed tools. and certification willnot always assure that the operator isskilled enough to accomplishall PLATING TOOL COVERINGS possible jobs thatmay be encountered. Much of the required skill can be gainedonly from actual Cotton batting of surgical grade U.S.P.long plating experience. Newly trainedand certified fiber, sterile cotton is the mostcommon tool operators should generally workunder the covering. It is fastened to the anodeto hold and guidance of an experiencedoperator for a distributethe solutionuniformly.Cotton minimumof30days.Ifthereareno batting alone can be used for jobsinvolving a experienced operators at the facility,experience few short preparing and platingoperations or to can be gained by limiting the plating workto facilitatemaximumtooltoworkpiece simpleapplicationsatfirst,avoiding jobs conformanceforplatingincorners or on requiring heavy plating buildup,especially for irregularly shaped areas. When longertool cover critical and rubbing contactapplications, and life is desired, cotton, Dacronor cotton-Dacron gradually progressing tomore difficult tasks. In tubegauze sleeving should be usedover the either event, the plating vendoror distributor cotton batting. In addition to cottonbatting and should be consulted wheneverplating problems tubegauze, Dacron batting, Pellon andtreated arise. If the problem cannotbe resolved by "Scotchbrite" may alsobe used asplating consultationorifa plating job is beyond tool coverings. in-house capability, vendorservices should be required to assist with the actualplating and to OPERATOR QUALIFICATION provide concurrent on-the-jobtraining.

Only qualified operatorsare permitted to HEALTH AND SAFETY PRECAUTIONS performproductionplating.The cognizant plating shop and the quality control department The plating solutionsmay be poisonous and maintaina listofqualified operators. may produce fumes which are irritatingto the Qualification of operators is theresponsibility of eyes. For these reasons, you must takethe the performing activity andis based on the following precautions: operator's ability to: You must wear safety glassesor face 1. Successfullycompletea process shield, rubber gloves andrubber apronor equipmentmanufacturer'straining course, laboratoryclothingat all timeswhen in-house, or other approved trainingcourse. To electroplating. Chapter 14METAL BUILDUP

NEVER let your skin come in contact ALLOY: Metallic combination of twoor with the solutions. If it does occur, wash your more elements. skin thoroughly with soap and water. ALTERNATING CURRENT(a.c.): ---,en electroplating in air conditioned Electricalcurrentthathasan compartments, alternating nonventilatedcompartments, direction of current flow, usually 60 timesper confined areas of ventilated compartments,or in second. compartments with only minimal ventilation, be sure that portable ventilation exhaust blowers \ AMPERE-HOURS (also AMP-HRor Ah): A are installed and operating BEFORE you begin. m)sure of a total quantity of electrical current Direct the exhaust hose from these blowersto sue as may becontainedinabattery. anadequatelysized exhaustterminalor Co parable to a quantity or volume ofwater. dischargedirectlytotheweatherwhere practical. AMPS, AMPERES, or AMPERAGE:A measure of the quantity of electrical current Warning signs must be postednear the flowing through a conductor suchas wire or a operation to warn personnel that toxicand conductive solution. Comparable torate (gal per poisonous chemicals are being used. minute) at which water flows througha pipe. Adhere strictly to the safety precautions noted in the caution plate on the equipmentor ANODE: Positive terminal ina conductive specifiedinthemanufacturer's.operating solution. Metal ions in the solution flowaway procedures. from thepositiveterminal.Inthereverse direction, the workpiece is positiveand there is a TERMINOLOGY tendency to remove materialor "etch" the workpiece.Intheforwarddirection,the Contact electroplatingis workpiece is negative and metal ionsflow to the highly technical part; that is, the workpiece is plated. and introduces many terms of whichyou probably have little knowledge. Thenext few pages contain definitions which will be of great ANODE-TO-CATHODE SPEED: The rate of benefit as you study theprocess of contact movement of the plating tool relative to the electroplating. Read them carefully and then surface being plated. The relative movementcan refer to them asnecessary as you progress be obtained by moving the tool, bymoving the through the remainder of the chapter. workpiece, or by moving both.

ACTIVATE: Removing passive film whichis ANODIC CORROSION PROTECTION: normally present or which forms quicklyon Corrosion protection offered bya deposit more certainmetals. Thisisconducted using an reactive than the base material. The deposit, appropriatesolutionandforwardcurrent. therefore, corrodes preferentially to the base Activating improves adhesion of the platingto material. The coating, therefore, doesnot have follow. to be pore-free.

ADHESION: Thedegreetowhich an BAKE: Heating a part for several hours electroplate is bonded or "sticks" to the at base approximately400°F,usuallytoremove material. entrapped gases such as hydrogen.

ANODIZED COATING: An oxide coating BATH PLATING:Electroplatingby formed on aluminum by making it theanode in immersing the workpiece ina tank of plating an appropriate solution. Thickness varies from solution. 0.000020 to 0.001 inch dependingupon the application. BHN: Brinell Hardness Number.

14-17 437 MACHINERY REPAIRMAN 3 & 2

BURNED DEPOSIT: A loose,powdery, COHERENT: Holds firmly together defective deposit applied by improper as one plating. piece; that is has high resistanceto breaking Burned deposits tend tooccur first at high apart in pieces. current density areas, such as masked edgesand sharp external corners, andcan be recognized by beingdistinctlydarkerincolor. A burned CONSTANT FACTOR:Thefactoris constant deposit can be covered, but the burnedlayer will andisnotaffectedbyplating have poor cohesion and the funlsurface will be conditions, such as current density,temperature, rougher. Moderate, localizedburning can be etc. A certain number of amp-hr,therefore, tolerated in most applications. Severe, always deposits a certain'volume ofmetal from overall the solution. burning requires that the platingoperation be stoppedtoallowchemical or mechanical removal of the burned layer. Platingthen can be CONTACT AREA: Thearea of contact resumed after the surface is properlyprepared. made by a platingtool on the workpiece measured in square inches. CARBURIZED: A part that has beencase hardened by impregnating carbonin the surface CURRENT DENSITY: The platingcurrent and then heattreating the part. being passed per square inch ofcontact area. The value is determined by dividingthe plating CASE HARDEN: Hardeningan iron base current by the contact area. When 10amps are alloy, such as steel or cast iron,so that the drawn with a tool making 5square inches of surface layer or case is substantiallyharder than contact with a part, the current densityis 2 the interior. amps per square inch.

CATHODE:Negativeterminalinan DENSE: Has no voids, cracks,or pores. electrolyte. Metal in an electrolyte flowsto the negative terminal. In the "forward"or plating DESMUT: To removea loose, powdery, direction, the workpiece is negativeand metal darker surface film formed bya previous etching flows to it. operation.

CATHODE EFFICIENCY: Thepercentage DIFFUSION: The movement ofatoms in a of current flow (amperes)or quantity of current solid, liquid, or gas; usually tendsto make the (ampere-hours) used to electroplate metal.(See system uniform in composition. NOBLE METALS.) The remainderof the total amperes or ampere-hours (current) deposits DIRECT CURRENT(d.c.):Electrical hydrogen which dissipates in theatmosphere. current that flows in onlyone direction.

CATHODIC CORkOSION PROTECTION: DPH or DIAMONDPYRAMID Corrosion protection offered bya deposit more HARDNESS: A microhardnesstestthatis noble than the base material. The depositmust suitable for testing the hardnessofthin or small be pore-free, since the base materialwill corrode areas, such as an electrodeposit. It develops in preference to the coating. aqu areimpressionlDPHhardnessesare converted to more familiar Brinellor itc values using conversion charts. CHROMATE COATING: A coatingapplied on many metals, often zinc and cadmium.The colorofthecoatingvariesfrom almost DRAG-OFF: The solutionleftonthe transparent to yellow or brown. It is appliedfor workpiece when platingiscompleted. This additionalcorrosionprotection,decorative solutionwill be lost in the followingrinse reasons, or as a base for . operation.

14-18 Chapter 14METAL BUILDUP

DUCTILITY: The property ofa material that permits it HARDCOAT: An oxide coating formedon to be stretched permanently aluminum by makingitthe anodeinan without fracture. The opposite of brittleness. appropri.ae, solution. Thickness variesfrom 0.001to a.005 inch. The coating is used ELECTROLYTE: A solutionthatwill primarily for wear resistance. conduct electricity. HARDNESS: The ability ofa material to ELECTROPOLISH: To polishasurface resist indentation. Brinell and It,are common whileelectrochemicallyetching in a special hardness tests. solution. ETCH: To HYDROGEN EMBRITTLEMENT: Embrit- electrochemicallyremove tlement of a material caused by absorptionof materialfromasurface.Conducted with hydrogen. Occurs only with certain appropriate solution and reverse current. materials such as steel overl40 Itc, titanium, andcertain harder stainless steels. "F"or FACTOR:Theampere-hours requiredto depositthevolume of metal IMMERSIONIDEPOSIT: A metallic deposit equivalent to a 0.0001-inch thicknesson 1 whichforms on morereactive square inch of area. metals by chemical reaction with certain platingsolutions. No flow of d.c. current is required.Immersion FORWARD CURRENT: Direction ofd.c. deposits ordinarily havepoor adhesion. current flow in which metal ions tend to flow away from the anode and toward the workpiece. IONS: Electrically charged atoms Theanodeis or groups positivelycharged andthe of atoms in a solution. Metalatoms are charged workpiece is negatively charged. positive and migrate toward the cathode. FRETTING: Wear that occurs betweentwo KNOOP: A microhardness test which is adjacent surfaces caused by a minute back dad suitable for hardness testing thinor small areas forth rubbing movementor vibration. such as an electrodeposit. Knoop hardnessvalues are converted to more familiar Brinellor It, FRETTING CORROSION: Wear thatoccurs hardness values, using conversion charts. between two adjacent surfaces caused bya minute back and forth movement or vibration. LITER: Volume equal to 1.0567quarts. The wear is accompanied by formationof oxides from the small, worn off particles. MATTE: A dull, satinyappearance resulting from a fine microroughpess. GALLING: The damaging ofone or both metallic surfaces by removal of particles from MICROCRACKED: A typeof localized areas during sliding friction. deposit structure in which there arenumerous fine surface-to-basemetal cracks. Cracks areso GASSING:Evolutionof hyd:ogengas numerous and fine that they can be seen only at bubbles on the workpiece, either by activating, high magr ificatinns. plating, or by chemical attack of theactivator on chromium. MICROPOROUS: Atypeofdeposit structure in winch numerous finepores exist. GRAIN STRUCTURE: All metalshave a The pores are so numerous and finethat they granular or cellular structure. The grainsize can be seen only at high magnification. varies from invisible to the nakedeye to perhaps 1/8 inch in diameter. Grain structure refers to MICROSTRUCTURE:The the overall appearance of the structureof arrangement of deposit when viewed at SOXmagnification and grains. over.

14-19 4 3:). MACHINERY REPAIRMAN 3 & 2 mn.=1.. MILKY: A type of deposit appearance that PREWET: Applying plating solution to the is almost bright but has a cloudy appearance due surfa'3e before applying current. The operation to a very fine microroughness. improves adhesionof deposits from certain solutions by ensuring that plating beginson a NITRIDED:Casehardenedsurfaceon surfacecoveredallover withfullstrengt\li certain steels formed by heating in a nitrogen solution. II containing material. Nitrogen diffuses into the surface, causing a hard case. Rc : Rockwell C Hardness.

NOBLE METALS: Metals may be classified REACTIVE METALS:Metals maybe, according to their tendency to be corrodedor classified according totheir tendency to be chern Ica'' ittacked. The noble metals are less corroded or chemically attacked. The reactive easily 'died or chemically attacked. They metals are more easily corroded or chemically include metals such as copper, nickel, and gold. attacked.Thdyincludemetalssuchas aluminum, steel, and zinc. NODULAR: Type of electrodeposit that has, rounded projections on the surface, visible toy REVERSE CURRENT: Direction of lc. the naked eye upon close examination. current flow in which metal ions tencl to flow away from the workpiece and toward the anode. "i he anodeisnegatively OHMS or SYMBOL. n: A unit ofmeasure chargedandthe resistance to the flow cf electrical current. workpiece is positively charged. SACRIFICIAL CORROSION PROTEC- OXIDE: Reaction product ofa metal with TION: Anodic corrosion protection. oxygen. SCALE: Surfaceoxidation on a metal PASSIVATE: The formation ofa thin, caused byheatinginairor an oxidizing invisible oxide film on certain metals which atmosphere. impairs adhesion of a following electroplate. SEIZING: Same as GALLING. pH: A measurement value on a scale of 0to 14 of the acidity or alkalinity ofa solution. 0 SMEARED METAL: Deformed material for example is strongly acidic, 4 less acidic, 7 near the surface caused by machining, grinding, neutral,10 mildly alkaline, and 14 strongly or wear. alkaline. STRESS: Pressure(force per unit area) PLATING RATE: The rateat which a existing in a deposit. Tensile stress isa "pulling deposit builds up. Ih this manual it is expressed apart" type of stress. Compressive stress isa in inches per hour. "pushing together" type of stress.

PORES: Small random holes ina deposit STRESS CRACK LIFTING: The type of just barely visible to the nakedeye. deposit structure caused by the development of surface-to-base metal cracks which then curlup POROUS: A type of deposit that contains on the edges because of poor adhesion. Can be pores. seen visually or at low magnification. Similar in appearance to a dried up clay lake bed. PREPLATE: A thinpreliminary plating applied using plating solution other than the STRESS CRACKS: Cracks running from the final desired solution. Preplatesare used to plated surface to the base material. Can beseen improve adhesion. visuallyorat low magnification. Normally

14-20.

44(1 Chapter 14METAL BUILDUP detrimental only when corrosion protection is conditions, therefore, must be controlledto get desired of the plating. desired thickness of deposit. STRIPPING: Removingan electroplate from a workpiece by chemical or electrok liemical VOLTS: A measure of the electricalforce means. applied. Comparable to waterpressure.

TANK PLATING:SameasBATH 'WATER BREAKS: The breakingof a water PLATING. film into beads such ason a waxed car. THROWING POWER: The abilityof a APPLICATIONS platirri solution to providea uniform deposit on a part that ha.,surfaceirregularities readily The contact platingprocess is a relatively visible to the nakedeye. A solution with good new and rapidly expanding field. When usedfor throwing power is particularlyuseful for pit depositingacorrosionresistantcoating, filling since relativelymore plating is applied at electroplating has shown sufficientsuccess to\ the bottom of the pit. permit almost unrestricteduse of the process in \ this area. However, the vast: geld VARIABLEFACT_ 3k: of possible Factorisnot applications for repairingwow or damaged parts constantbutvariesdependingon plating ofhigh-speedrotatingandreciprocating conditionssuchascurrentdensityand temperature. A given machinery has just begun to beexplored and number of amp-hr, warrantsa morecautious therefore,willdeposit different amounts of approach. Requirements lur contact platingare specified in metal, depending on platingconditions. Plating Table 14-1 whichdefinestheareasof

Table 14-1.Requirements For ProductionContact Plating

Allowable Class Thickness (Max) Restrictions Qualification Requirements

I No limit' None See Operator Qualifications

II 0.030" None

III 0.020" Excluding Class IV Original qualification plus plating of a mock-up and V simulatingthe production plating. The plated mock-up must be approved by the Quality Control Department of the performing facility.

IV NAVSEA Approval V required on a case basis.

1 Limitations to be governed bypractical and economical use of the metals deposited.The material man- ufacturer's recommendations should not be exceeded. 2Thickness limit does not apply to fillingInpits, scores, dents, etc. where the total surfacearea comprises 10% or less of the area to be plated. The maximum allowable platingthickness shall not exceed that recommended by the material manufacturer.

14-21 4 4/ MACHINERY REPAIRMAN 3 & 2

permissibleuseofcontactplating.For 0-Ring Grooves and Sealing Surfaces simplification,applicationsareclassifiedas follows: Repair of pits, scratches, andgouges on parts used for air,oil,salt- and freshwater Class I: Platingusedfordecorativeor service. corrosion preventive functions only. Close Tolerance: Mating Parts Class II: Parts that remain in staticcontact with other plated or unplated parts. Pump impellers: Repair of worn bores and keyways to restore design size 'and fiton Class III: Parts that make rubbing contact with shaft. otherplatedorunplatedparts, excludingti,usewhichapplyto Hydraulic Equipment Class IV. Scored,scratchedpittedor gouged Class IV: Rubbing contact parts in elements of surfaces of cylinder walls, tailrods, steeringgear turbine/reduction gear, turt,,,u- diesel rams, spool valves, and 0-ring seal grooves. electric power generating.nits, and main propulsion shaftings. Masts,Periscopes,Antennas,and Associated Hull Fittings Class V: Parts under the cognizanceof the Nuclear Power Division. Shafting

List of Successful, Typical Areas worn by contact with seals and Repair Applications packing.

Steam Valves Bearing Seats, Saddles, and Supports Repair turbine nozzle control valve seat's Ball Bearings: Plating of shafts and bores hardfacingbyplating0.003-0.005inch to reestablish close tolerance fits. Theuse of an thickness of cobalt overcopper and nickel outer layer of tin (0.002 to 0.003 inch thick) substrates. Apply a thickness has produced significant results as required to in reducing repair steam cutting and erosion damageand fretting of bearing bores in electricmotor end restore valve seat geometry. bells and also contributes to noisereduction. Applications Approved by NAVSEAon Sleeve Bearings: Plating of seats, saddles, a Case Basis and supports to correct for oversizemachining and out-of-roundness caused by distortion. Repair of steam turbine rotor bearing journals. Flanges and Flat Surfaces Repair of diesel engine crankshaft main Steamturbinecasingjointflanges: bearing journals. Repair steam cuts and erosion damage. LIMITATIONS Diesel engine cylinder blocks: Restore mating surfaces damaged by fretting. Cracks:Plating cannot be madeover areascontainingcracks.Cracksmustbe Wave guide plumbing: Plating flange seal completelyremoved bygrindingorother areas to provide corrosion resistant metallic mechanicalmeans.Fill shallow grooves by gaskets. copper plating and then plate the area with the

1422

4 4 1,,9 Chapter 14METAL BUILDUP

specifiedmaterial. Repair deep grooves by literature covering the use of theirproducts. welding. You should closely follow these instructions, especiallythose Chromiumplating onexisting concerningproceduresfor bath preparing base metals for plating and chromium deposits: Brushing chromiumplating the use of on existing bath chromium deposits has not individualplatingsolutions,toensure satisfactory plating results. A list of beenconsistentlysuccessful.Theproblem vendors' experienced by vendors and literature is shown in table 14-2.Detailed, step users alike has been by step contact plating procedures for poorbonding.Forthisreason,selective the most depositionofchromium on commonly usedmetalsarealsofound in existingbath Engineered chromium depositisnot recommended for Uniform Method and Standard. engine parts that make rubbing No. 3426-801. (Copiesmay be obtained from contacts. To Commander,Mare plate such parts, completelyremove previous IslandNavalShipyard, Vallejo, California 94592). Another chromium deposits prior to.contactplating. As Government analternate, apply a nickel document onthissubjectisMIL-STD-865 flash over the (USAF).(Copies existing bath plated chromium andfollow with maybeobtainedfrom contact chromium or other plating material. Commander,Hill Air Force Base, OOAMA/ OONEO, Utah 84401.) Babbitt restoration: The feasibilityof contact deposition of babbitton worn or Refer questions arising from difficultywith damaged babbitt surfaces of bearings isbeing equipment or solutions to themanufacturer or evaluated by a government laboratory.Pending his nearest local sales representativeand send a affirmativerecommendations,babbittres- report,identifyingtheproblemandits toration by the contact platingprocess should resolution,to NAVSEC (Code 6101D) for not be made. information.

Depositionof chromium:Contact platingsolutions can produce deposits with QUALITY CONTROL mechanical properties which willsatisfy the requirements for most plating work. Therefore, Quality controliscomprised of several selective plating coatingscan normally be used factors: documentation,process control, general to repair or as a substitute for bathplated (allplating) inspection, and liquidpenetrant coatings. The exception to this is theuse of inspection of plating for rubbingcontact service. chromium to refurbish worn parts.Deposition of chromium by coatact electroplating is not Documentation recommendedbecausethedepositis much softerthanthatdepositedbybath electroplating, the thickness of the buildupis The c )gnizant quality controldepartment limited, and the process is tediousand slow. As will ensure that plating producedmeets the an alternate, other metals suchas cobalt or requirements of 'theapplicable specifications nickel will provide wear resistanceand hardness listed below: propertieswhicharesuitableformost applications where chromium wouldnormally Deposit Specification be used. For areas requiringextensive buildup, deposit copper up to about 0.020inch of the Cadmium QQ-P-416 final dimension, and then depositan outer layer Chromium QQ-C-320 of cobalt, nickel-tungstenor cobalt tungsten for Copper Mil-C-14550 greater wear resistance and surface hardness. Gold Mil -G-45 204 Nickel QQ-N-290 PROCESSING INSTRUCTIONS Silver QQ-S-365 Tin The equipment and solution manufacturers MA-T-10727 Tin-lead Mil-P-81728 havep re p a redcomprehensive instruction Zinc QQ-Z-325 14-2344 Jf, MACHINERY REPAIRMAN 3 & 2

Table 142.Publications of Major Vendors of Contact Plating

The major vendors of contact plating equipment and materialare listed below. These vendors also provide consultant and operator training services.

VENDORS PUBLICATIONS*

Dalic Process Operating Instruction Manual

SIFCO Metachemical Division of Steel Containing Technical Bulletins: Improvement and Company IM-1, 2, 3, 10 and 11 through 20 935 E. 63rd Street IM-200, 202 through 210 Cleveland, Ohio 44103 IM-302, 303, 305, 307, and 308

Piddington & Associates Ltd. Equipment and Material price list 3221 E. Foothill BOulevard Pasadena, Calif. 91107

Selectron Process Technical Instruction Manuals SI-115 and SI-130

Selections Ltd. Technical Bulletins SL-81, SL-82, SP-1023 and 116 E. 16th Street Navy-Fact File New York, N.Y. 10003 Selectron "Plating Guide" slide rule Vanguard Pacific Inc. 1655 Ninth Street Equipment and Material price list Santa Monica, Calif. 90406

*Publications may be obtained on request.

Process Control 3. A sketch of the area requiring plating. All parts to be plated will be handled in 4.Identification of base metal. accordancewitha writtenProcess Control 5.Final thickness of deposit required. Procedure approved by the individual activity. Plating work should be set up toensure a 6.Plating material(s) to be used. smoothflowofplating work frominitial 7.Step by step processing procedure. engineering approval through final inspection. Adequate records must be kept of work 8. Method of surface finishing (grinding, performedbythe plating shop.Processing honing, etc.) informationrecordedshouldincludethe 9.Final inspection, including method and followin dimensional checks when applicable.

1.Name of ship, date and job order Items 1 through6aboveshouldbe number when applicable. engineering and job planning functions and 2.Description of part to be plated by represent the minimum information required by proper name and drawing piece numbers. the plating shop.

14-24 Chapter 14METAL BUILDUP

Process control records of completed work MIL-STD-271. Indications must not be are a ready reference for handling repeat jobs greater thar1/16inchandtheconcentrationof and for assessing the capability ofthe plating indications must not exceed 3 in shop. any square inch area. For chromium plating only, because of the General (All Plating) inherent crazying characteristic of thematerial, water washable penetrant material (GroupIII or Inspection Procedure IV of MIL-STD-271)may be used for liquid penetrant inspection. Visual Inspection: All platingsmust be smooth andfree of blisters,pits, nodules, porosity, excessiveedge buildup, and other POWER PACK COMPONENTS defects which will affect the functionaluse of theplated part. The finished plating must The equipment must contain safety conform to the required design features surface finish for in accordance with MIL STD 454.Operations the part and must be free of burningsand stress that could create personnel hazards concentrations. Burning is or result in defined as rough, damage to the equipmentor work will be noted coarse grained, or dull plates caused by localized on a caution plate permanently attachedto the high current density or arcing.Highly stressed front of the equipment. deposits are normally indicated bycracks or crazing. The parts of the power packammeter,d.c. circuit breakers, voltmeter, ampere-hourmeter, Adhesion Test: The adhesiontestis startandstop performed with Scotch #250 buttons,outputterminals, tapeoran forward-reverseswitch,outputleadsare equivalent high tack strengthpressure sensitive tape as follows: discussed below and labeled in figure14-11.

1.Thoroughly clean and dry the plated AMMETER surface. 2. Cut a piece of 1 inch wide unusedtape approximately 6 inches longer than the width of There is at least one ammeteron the power the plated area. pack. The ammeter 3.Stick the tape across the width measures the rate of current of the flow through the plating tool.Since the rate at plated area so that approximately1 1/2 inches of the base metal which metal is being applied is exactlyor nearly on each side is taped. Tamp proportional to the rate ofcurrent flow, the thetapedowntoensure thatitsticks ammeter gives a second to second ideaof how thoroughly. fast you are plating. 4. Grip the loose end of thetape and rip rapidly upward (at right angleto the plating) removing the tape witha single jerk. D.C. CIRCUIT BREAKERS 5.Inspect the tape. Any plating adheringto the tape is cause for rejection. power packs have at least one d.c. circuit Platings for Rubbing Contact Service 2 All breaker. Its purposesare to prevent overloading the power pack and to minimize Inadditiontothe damage to the generalinspection, workpiece in case there isan accidental direct platings for rubbing contact servicemust meet shorting of a lead or a tool the liquid penetrant inspection. on the workpiece. VOLTMETER LiquidPenetrantInspection:The finished plating will be inspected with Group I Thevoltmetermeasuresthevoi.age liquidpenetrantinaccordancewith (electricalpressure)appliedacrossthed.c.

14-25 4'+ 5 MACHINERY REPAIRMAN 3 & 2

' 4g, ekti,".11;# 44,141

28.449 Figure 14-11.Dalic power packsdigital display. circuit or through the solution. Different voltage through the d.c. circuit and allows control of the ranges are used with different solutions. The thicknessofdeposits.Theformulafor "volts" control knob makes the adjustments for determining ampere-hours will be discussed later applied voltage, whichisthe initial step in in this chapter. The meter also has a zero reset. obtaining the proper plating conditions. The resetbuttonispushedafter cleaning, etching, etc. are finished. When the computed AMPERE-HOUR METER amp -hours are passed, the plating operation has been completed. The white dot below, the numbers indicates the decimal point; example Theampere-hourmetermeasuresthe 0012.61 means 12.61 amp-hours have been quantity(amps X time)ofcurrentpassed passed. 14264 4p Chapter 14METAL BUILDUP

START BUTTON you should ube a plating tool that gives 20 square inches of contact area. Thestart button energizesthecircuit b. You are to use code 2080solution on a breaker and makes the d.c. circuit operative. job where the contactarea is up to 5 square inches. Use a 30-25 power packor larger on this STOP BUTTON job.

The stop button deenergizes the d.c.circuit OPERATION OF POWER PACK and makes it inoperative. . PRIOR TO PLATING, take the OUTPUT TERMINALS following steps on the power pack you willuse:

Each power pack has at leastone black and 1.If the power pack has one red output terminal. Larger power packs an external ground post, connect the post with sufficientsize wire have a number of black and redterminals, to a suitable ground. sometimes of various sizes. Plating tool leads, 2.If necessary, connect the suitablemale usually color coded red,are always connected to connector to the a.c. input line, and a red terminal. The alligator clamp lead, usually connect to color coded black, proper (volts and phase) a.c. power supply. is always connected toa 3. Turn the "volts" controlto extreme black terminaL A leadcan be connected to any "low" position. terminal if the color and size are compatible. 4. Connect theappropriatesize output leads for the plating tools FORWARD-REVERSE SWITCH you will use to the appropriate terminals on thepower pack. (Black alligator clamp leadto black terminal; red Theforward-reverseswitchchanges the plating tool lead to red terminal.) direction of current flow in the d.c.circuit. DURING PLATING OPERATION. OUTPUT LEADS Press the "start" button toenergize d.c. Larger power packs havea number of wire circuit. leadsofdifferentsizes.Smallleadsare correlated with small terminals for small tools Adjustthe"volts" controlandthe where low amperages will bedrawn. Large size "forward-reverse"switch wire leads are correlated with large asnecessaryfor terminals for various preparatory and platingsteps. large tools where high currents willbe drawn. Press the amp-hour meter buttonto reset the indicator to zero just priorto plating. SELECTION OF POWER PACK When plating The power pack size is determined is completed, press the by the "stop" button to deenergize d.c.circuit. solution used and the plating toolcontact area. Use Table 14-3 in selecting the size.It lists (1) the plating tool contact area desirable with a PLATING TOOLSSELECTION given solution and power packand (2) the AND PREPARATION power pack size required for a given solution and plating tool contactarea. Selection and preparation of theproper preparatoryandplatingtools EXAMPLES IN USING TABLE 14-3: isa VERY IMPORTANT factor in determininghow rapidly and effectively you carry outa particular job. In a. You are to use a 60-35 power pack and plating operations (preparation of code 2050 solution ona given job. If possible, the surface or plating), work is done only whereand when the

14-47 MACHINERY RI.??A':.:.;vf..\N

,-----.---- WW1M11, Table 14-3.Optimum Plating Tool Contact Areas (sq to.)ttJ: Various Plating Solution and Power Packs

Solution Code Power Packs: 10-15 15-20 30-25 60-35 100-40 150-40 200-25 10 Amp 15 Amp 30 Amp60 Amp 100 Amp 150 Amp 200 Amp Antimony 2000 2 6 12 24 40 60 80 Bismuth 2010 4 10 20 40 67 100 iD4 Cadmium 2020 1 3 5 10 17 25 34 Cadmium 2021 3 8 15 30 50 75 100 Cadmium 2022 2 5 9 18 29 43 57 Cadmium 2023 2 4 8 15 25 38 50 Chromium 2030 1 3 5 10 17 25 34 Chromium 2031 3 8 15 30 50 75 100 Cobalt 2043 1 2 5 9 15 22 29 Copper 2050 2 5 10 20 34 50 67 Copper 2051 2 5 9 18 29 43 57 Copper 2052 2 5 9 18 29 43 57 Copper 2054 1 4 I 14 23 34 45 Copper 2055 0.5 2 3 5 8 12 16 Iron 2061 1 3 5 10 17 25 34 Lead 2070 3 8 15 30 50 75 100 Lead 2071 3 8 15 30 50 75 100 Nickel 2080 1 3 5 10 17 25 34 Nickel 2085 1 2 5 9 15 22 29 Nickel 2086 1 3 6 12 20 30 40 Nickel 2088 1 3 5 10 17 25 34 Tin 2090 3 8 15 30 50 75 100 Tin 2092 3 8 .15 30 50 75 100 Zinc 2100 2 5 10 20 34 50 67 Zinc 2101 1 2 5 9 15 22 29 Zinc 2102 1 2 5 9 15 22 29 Zinc 2103 1 2 5 9 15 22 29 Gallium 3011 4 10 20 40 67 100 134 Gold 3020 4 10 20 40 67 100 134 Gold 3021 ir; 4 10 20 67 100 134 Gold 3022 4 10 20 40 67 100 134 Gold 3023 20 60 120 240 400 600 800 Indium 3030 3 8 15 30 50 75 100 Palladium 3040 2 5 10 20 34 50 67 Platinum 3052 1 3 5 10 17 25 34 Rhenium 3060 2 5 10 20 34 50 67 Rhodium 3072 2 5 10 20 34 50 67 Rhodium 3074 3 8 15 30 50 75 100 Silver 3080 2 4 8 15 25 38 50 Silver 3081 5 15 30 60 100 150 200 Silver 3082 2 6 12 24 40 60 80 Silver 3083 . 2 6 12 24 40 60 80 Nickel-Cobalt 4002 1 3 5 10 17 25 34 Tin-Indium 4003 3 8 15 30 50 75 100 Tin-Lead-Nickel 4005 4 10 20 40 67 100 134 Cobalt-Tungsten 4007 1 3 5 10 17 25 34 Nickel-Tungsten 4008 1 3 5 10 17 25 34 Babbitt-5AE 11 4009 5 15 30 60 100 150 200 Babbitt-Soft 4010 5 15 30 60 100 150 200 Babbitt-Navy #2 4011 5 15 30 60 100 150 200

14-28 4 4 s Chapter 14METAL BUILDUP

tool meets the part. Rapid,proper, and uniform solution to be used, the size of the processing of a part largely depends area to be on: plated, and the shape of thearea to be plated. 1.Whether the tool you select covers a In determining the optimum contactarea, sufficient or optimum contactarea on the part. refer to table 14-3 which gives the 2. maximum Whether the tool covers the full length contact area required for a given solutionto be of an inside diameter, outside diameter,or flat plated and the power pack to be used. area. 3.'How you pump the solution through the If, for exan ple, Code 2080 solution plating tool when plating higher thicknesses is to be on used with a 60-amp power pack, themaximum 1Rsger areas. contact area required is 10 square inches. PREPARATORY TOOLS

The preparatory steps (cleaning,deoxidizing, etching,etc.) arerelativelyshortsteps as NOTE: FORMULAS1 THROUGH 7 compared to the plating operation. Selectionof ARE DISCUSSED AT THE END OF the preparatory tools, therefore, is notas critical THISCHAPTER, BEGINNING ON as for the plating tool. The preparatory tools, PAGE 14-65 however, should contact approximately 10%or more of the area to be plated, and, if easily practicable, cover the full length of thearea to be plated to assure uniform preparation. Formula 3 can be used alternatelyOp obtain this Sufficient solution is supplied bydipping for value. The maximum contactarea is required on solution. In most cases, a standard platingtool verylarge will meet the above requirements areas only. On very smallareas and special optimum contact area is maximumcontact that preparatory tools need not be made. can be practicably obtained; that is, full contact for flat areas and 50% of the totalarea for Proper Plating Tools outside diameters (0.D.) and insidediameters (I.D.). In other words, optimumcontact area for a flat surface is full contact up to an The plating step generally ,represents area the the size given in table 14-7 and for largerareas it major part of a complete plating operationand remains that size. selection of the proper plating tool is, therefore, more critical than for the preparatory tools. The On O.D.'s and I.D.'s. where itis usually higher the thickness of plating to beapplied, the difficult to get a tool that contacts larger the area to be plated and the more than larger the 50% of the total area, optimumcontact area is number of partstobeplated,the more 50% contact area up to a contact important it is to have the area of the size proper tool. It is also given in table 14-3; for larger 0.D.'sand I.D.'s it importantto havethepropertool when remains that size. uniform-v of deposit thickness isnecessary.

Optimum Contact Area Covering Full Length for Plating Tool

Covering the full length of A tool that gives optimum contact an O.D., I.D., or area on flat surface with a tool makes itrelatively easy the area to be plated lets you platea good to get a uniform thickness. When thetool does deposit as fast as possible. Optimum contact not cover the full length, problems arise. area depends on the power pack to be used, the For example, take the case of trying to platean O.D. 14_194a MACHINERY REPAIRMAN 3 & 2

3 inches long with a tool that willcover only 2 Use the following procedure to determine if inches. If you move the tool as shown in figure it is worthwhile to use solution-fed tool. 14-12A, the center 1 inch is always covered, but

in moving the tool to the ends there is less 1.Use J. ormnia 1 (page 14-65)to coverage time. The plate distribution you would determine amp Ilo,;r_ required for one part and getis shown at the bottom (plating). The then multiply by the number of parts ifmore alternative to this is to move the tool as shown in than one. figure 14-12B.Yougetanevenplate 2.Determine the +oe of tool to be used distribution, but now you wastesome time with and also its conte area. Then use formula 4 the tool off the part. This motion, also,may not (page 14-66) to determine total plating time if be practical if there is a shoulder atone side. solution is pumped through the tool. The same situation applies to I.D.'s and flat surfaces. Summarizing, always try to have the Since dipping for solution usually doubles tool cover the full le-gth of O.D.or I.D. or the plating time, the value arrived at in step 2 above full length or width of a flat surface. also represents the extra time you will spend dipping for solution. This possible savings in time can help you determine if it is worthwhile Solution-Fed Tool to set up to pump solution.

Standard Tools Solution-fed tools are used for plating high thicknesses on large areas of a large number of Standard tools (figures 14-13 and 14-14)are parts. It is, of course, not worthwhile touse a available for preparing and platinga wide variety solution-fed tool when a small thickness of of sizes and shapes of parts. Theseare described deposit is required on a small area ofone part. on the following pages. You can use standard Solution-fed tools are not used with precious tools if they meet the following requirements. metals, since a higher volume of a high cost solution is required. Solution-fed tools usually Preparatory Tools: double plating speed and improve quality and reliabilityofdepositbecausetb:,flowing 1.Cover approximately 10% ormore of solution (1) cools the anode, allowing higher area to be plated. currents to be passed; (2) ensures that sufficient 2.Cover full length. fresh solution is maintained in the workarea; and (3) eliminates time wasted in dipping for Plating Tools: solution. 1.Provide optimum contact area. 2.Cover full length. 3.Allowforpumpingsolutionwhen

Tool required.

NOTE: You must allow 1/8 to 1/4 inchon the radius for the tool cover when considering Part standard tools for 0.D:'s and I.D.'s.

Special Plating Tools Plating You should use special plating tools when A B standardplatingtoolswillnoteffectively accommodate a particular area to be plated. The 28A50 greater the thickness of plate desired and/or the Figure 14-12.Platingcovering the full length. larger the number of pieces to be plated, the

14 30 4 ) Chapter 14METAL BUILDUP

TOOL COMPONENTS Cat. No. Handle Anode Adapter AIR-COOLED (for smallareas and l.D.'s) Solution Dip AC 0 AC 1-3 AC0" .09 0 x 2" AC 1 AC 13 AC-1 .180 0 x 2.25" AC 2 AC 1.3 AC-2 .25' 0 x 2.25" AC 3 AC 1.3 AC-3 .31" 0 x 2.25" AC 4 AC 4-7 AC-4 .375" 0 x 3" AC 5 AC 4-7 AC-5 AC - SERIES -5" 0 x 3" AC 6 AC 4.7 AC-6 AC .75" 0 Y 3.5" AC 7 AC 4-7 AC-7 AC 1,0" d x AC 8 AC 4.7 AC-8 AC 2.25" x 1.5" x .75" AC 9 AC 4.7 AC-9 AC 2" x 3" x .75" 'AC 0 ANODE is platinumclad titanium

WATER - COOLED (for largerW.'s) Solution Dip

WC - 25 WC 25 WC-25 FG 1.125" 0 x 3.75" WC 40 WC 40 WC-40 FG WC SERIES 1.625" 0 x 3.75" WC 55 WC 75 WC-55 FG 2.125" 0 x 3.75" WC 70 WC 75 WC-70 FG 3" 0 x 3.75" WC 75 WC 75 WC-75 FG 3.125" 0 x 2.1n"

SOLUTION FED (for larger I.D.'s)

RF 15 F RF-15 FG 1.5" 0 x 3.75" c 20 F RF-20 FG 2" p x 3.75" RF 25 F RF -25 FG 2.5" 0 x 3.75" RF 30 F RF-30 FG 3" 0 x 3.75"

28.451 Figure 14-13.Standard plating tools. MACHINERY REPAIRMAN 3 & 2

TOOL COMPONENTS Cat. No. Handle Anode Adapter SOLUTION FED (for 0.D.s)

SCC-10 AC 4-7 SCC-10 AC 1" I.D. x 1" wide SCC15 AC 4-7 SCC15 AC 1.5" I.D. x 1" wide SCC-20 AC 4-7 SCC-20 AC 2" 1.0. x 1" wide SCC-25 AC 4.7 SCC-25 AC 2 5" I.D. x 1" wide SCG-25 G SCG25 FG 2.5" I.D. x 2" wide %%err SCG-30 G SCG-30 FG 3" I.D. x 2" wide SCC - SERIES / SCG- SERIES SCG-35 G SCG-35 FG 3.5" I.D. x 2" wide SCG-40 G SCG40 FC 4" I.D. x 2" wide

FLAT & MULTI-PURPOSETOOLS Solution Dip

FG 1 G FC-1 FG 2.5' x 2.5" x 1" FG G FG-2 FG 3.5" x 3.5" x 1" FG 3 G FG-3 FG 4.5" x 4.5" x 1"

SOLUTION FED

FF -1 F FF1 FG 2.5" x 2.5" x 1" FF 2 F FF-2 FG FG - SERIES / FF- SERIES 3.5" x 3.5" x 1" FF - 3 F FF.3 FG 4.5" x 4.5" x 1" FF - 4 F FF-4 FG 4" x 3" x 2" FF 5 C FF5 FG x 4" x 2"

NOTE: All anodes except AC-0are made of special grades of graphite. Anodes ofany size, shape or m:rterial can be made on short order, pleaseinquire.

28.452 Figure 1414.Standard plating tools.

14-32 4(.7;2, Chapter 14METAL BUILDUP

more desirable it is to use special tools, since This establishes one contact dimension. Toget there is more opportunity to offset the extra the second, divide the optimum contactarea by cost by savings in plating time. the first dimension. The height of the anode is not critical. It 1.Obtain required information on the job: should be high enough to accommodate the handle hole and solution flow lines. If the anode a. Amperage output of the power pack is too high, it just adds to tool weight. Heights to be used. of 1 to 2 inches are generally used. b. Plating solution to be used. 6.Select handles, solution inletfittings, c. Shape and size of the area to be etc. based on design plating amperage. When plated. dimensions of anodes are basedon optimum contact area, the plating amperage should be the 2.Determine the optimum contactarea amperage output of the power pack. When the using either table 14-3 or formula 3 (see page anodedimensionsarebasedon maximum 14-66). practical contact area, compute expected plating 3.Determinethemaximumpractical amperage using formula 4 (page 14-66). contact area: At this point you will finda ruler and a a. On flat surfaces it is the total area. helpful in sketching in the anode. Keep b. On O.D.'s it is 507 of the totalarea the following rules in mind: since one can always cover the full lengthbutonly 50%ofthe On radii for I.D. and O.D. tools, allow circumference. for the anode cover, usually 1/4 inch thick. c. On I.D.'s it is 50% of the totg, area since one can always cover theSfull Space the solution outlet holes coming length, but practically only 50% of out the working face of the anode at intervals of the circumference. Attempts to get at least every 1 inch in the direction of the more .than 50% contact on an I.D. are length of an 1.D. or O.D. tool and perpendicular generally defeated by coknpression of to the direction of tool movementon a flat the tool cover during plating. surface tool. This eliminates the possibilityof platingtapersthroughunevensolution 4. When the maximum practical contact distribution. In the other direction, they should area (3 above) is less than optimum contact area be at least every 2 inches toensure reasonably (1 above) the special tools should beas follows: complete wetting of the cover andto permit passage of current throughout the cover. The a. On flat areas the tool should be 1 or outlet holes are usually 3/32 inches in diameter. 2 inches wider than thearea to be plated. This allows for moving the Make the main distribution hole in the tool while plating. anode next to the inlet fitting at least 1/4 inch b. On I.D.'s and O.D.'s the tool should in diameter when using a small submersible cover the full length and one-half of pump and 1/2 inch In diameter when usinga the circumference. large submersible pump. This helpsensure that all outlet holes are reasonably well fed. 5. When the optimum contactarea is less Thefollowingexampleswillhelp than the maximum practical contact you area, the understand how to make the special toolsyou special tools should be designed to givethe may need in contact electroplating. optimum contact area. EXAMPLE #1: Intheinterestofgettingauniform thickness, the full length of an I.D.or O.D. and Platea16-inch length on /13 inch O.D. the smaller dimension of a rectangle is covered. tubing with .006 inch of nickel/Code 20r.Use

14-33 4 5 3 MACHINERY REPAIRMAN 3 & 2

a 200-amp power pack. You can rotate the part in a lathe. 64"

.1 Optimum contact area is 34 sq in. which is DRILL AND TAP TO RECEIVE INLET less than 50% of the total area to be plated. HOSE FITTING Covering the full length of 16 inches givesone I" contact dimension. The contact width around .11 the surface then is

34 CW = = 2 1/8 inches 16

Allowing for a cover thickness of 1/4 inch,a 6 3/4-inchradiuswillbeputinthe 16 inch X 2 1/8-inchface. help keep the rather long tool squarely on the part, use two .1."11..-

G-handles. Solution outlet holes will be slightly 101 largerthefarther away they are from the I solution inlet port. (See figure 14-15.) 101 1 17 IJ EXAMPLE #2: 0, 5-2- DIA. 10. , 64 OUTLET HOL ES II A 12-inch 1.D., 3 inches long requires 0.0035 SCALE 2 inch of nickel, Code 2085. The part isvery large Pi and cannot be rotated. Therefore, you must move the tool by hand. Use a 100-amp power 28.453 pack. The amp-hours required for the jobare Figure 14-15.Design of special tool.

Amp-hr = .015 X 35 X 113= 59 EXAMPLE #3: A tool such as the Rf30 will give a small Ten bearings must be plated ona 20 inch contact area, draw only approximately 30amps, and result in a plating time of 2 hours. It is long, 26 inch I.D. with .002 inch of babbitt, elected to make a pie-shaped tool which has the Code 4009, per side. The part will be rotated in a barrel rotator, leaving the I.D. accessible from a. disadvantage of having to be rotated in both ends. Use a 100-amp power pack. addition to being moved around the I,D. The optimum contact areais100 sq in. Sincethecontact lengthis20 inches,the b. advantage of being able to draw 100 contact width is 100/20 or 5 sq in. Solution will amps which reduces the plating time to be pumped in from both ends to obtainmore 0.6 hours. uniform solution distribution, since thickness control is critical. Use two G-handles to help In view of the difficulty in moving the tool, keep the tool properly located on the part. Mill make the tool 3 3/4 inches long to ensure full a channel into the anode face around the outlet contact along the length. The bore being 3 hole to get better distribution along the length inches long, the contact length retr gins 3 inches. of the anode. (See fig. 14-17.) (See fig.14-16.) The optimum contact area is 15 sq in. The contact width thenis PLATING TOOL ANODE MATERIALS

15 A CW= = 5 inches gradeofgraphitewithmaximum 3 resistance to breakage and anodic corrosion is 14-34 Chapter 14METAL BUILDUP

FRONT VIEW

s-) DRILL AND TAP TO IQ RECEIVE 11" INLET HOSE FITTING ' I 2 PLACES I"DIA- 1. Z mt. 3

I I I I r- I I

I I II I I, TYP, II II If'

DIA. TYp G HANDLES J2 DIA, J2 IL OUTLET HOLES IL. 22

DRILL AND TAP FOR HANOLE

SCALE 4 rye TYP

28.454 28.455 Figure 14.18. Design of special tool. Figure 14.17. Design of special tool. usedonmoststandardtoolsandinthe forward "Cleaningand Deoxidizing" and fabrication of special tools from block form. ' 'A c t i va ting"operations. Since thorough Other materials, however, have been used and cleaningofthetoolmaynot always be are recommended. Check the manufacturer's effectively accomplished, a given tool should be instruction manual for particular a, pileations. identifiedfor and used withonly one preparatory or plating solution, Care of Anodes

Use sandpaper, Scotchbeite, etc. to remove loose graphite from the working area of graphite PLATING TOOL COVERS anodes used as part of the recovering operations. This helps keep subsequently used solutions The platingtoolcover performs several clean. Then, thoroughly soak the anodes in clean important funk ',ions: water and wipe off the abraded area. Thoroughcleaningofthe anode is 1. It insulates the anode from the part and particularly important when the tool will be thereby (a) prevents damage to the part by used later with a different solution. Thorough direct shorting and (b) forces current to pass cleaning of the anode (or use of one tool for one throughthesolutionwhicl,allows operation) is of maximum importancein electrocleaning, plating, etc. to occur.

14-35 MACHINERY REPAIRMAN 3 & 2

2.It mechanically scrubs the surfacebeing plated ADVANTAGES, DISAD- which permits sound deposits tobe COVER TYPE VANTAGES, AND USES rapidly applied. Cotton FinalUsed to moderate degreeas 3.It holds and uniformly distributes the Tubegauze final cover. Very low cost solution where it is needed. andhighpurityand absorbency. Has less wear TYPES OF COVERS resistancethanDacron tubegauze.Usedasfinal Several covering materialsare used with the cover for preparatory tools plating process and they may be categorizedas and for rhodium plating. follows: Dacron FinalWidely used as finalcover Tubegauze especially for plating tools INITIAL COVER: Holds and distributes whereitssuperiorwear solution, but requires a finalcover since it is not wear resistant. resistancetocotton tubegauze isimportant. Low cost, moderate purity, FINAL COVER: Overlaycover on an initial and absorbency. cover to provide wear resistance. White Com bi- Used frequently for plating Scotch-nation COMBINATION COVER: Can be usedby toolsbecauseofits itself sinceitholds and distributes solution brite moderatecostandhigh uniformly and it has satisfactorywear resistance. purity and wear resistance. Absorbencyispoorand SPECIAL COVERS: Used for specialeffects therefore satisfactory only such as described below. when solution-fed toolsare used with workpiece under The following list of plate coveringswith tool. their advantages and disadvantages willhelp you Dacron Combi- Used frequently for plating in selecting the proper coveringfor a particular Felt nation ')1 because of its excellent plating job. wear resistance, absorbency, andmoderatecostand ADVANTAGES, DISAD- purity. COVER TYPE VANTAGES, AND USES Gray Special Used occasionally whena Cotton Scotch-Purposehigherthannormal Initial Widely used because of its brite Batting very low cost and excellent thickness,i.e.,0.005to 0.0.15 inch is required in absorbencyandpurity. a Cannot certaindeposit.Keeps be used %kith deposit chromium, Code 2031, and smootherthan copper,Code normalsinceithasan 2055. abrasive which polishes Requiresfinalcoverfor as wear resistance. plating is proceeding. One problem in usingthis Dacron Initial Used very little because of material is that an effect called"Plating in Cover" Batting itshighcostrelativeto cotton batting. Used as a usuallystartsin replacementfor approximately 10 minutes. cotton Itis batting with very corrosive the actual plating of solutions such as chromium metal in the form ofa fine 2031 and copper 2055. powder in the cover at the expense ofthismaterial

14-36 Chapter 14METAL BUILDUP

ADVANTAGES, DISAD- ADVANTAGES, DISAD- COVER TYPE VANTAGES, AND USES COVER TYPI- VANTAGES, AND USES

beingappliedonthe noi. conductive enough to workpiece. This is indicated Damage the part by shorting bybrighteningofthe ifthe thinfinal cover is surface being plated and a wornthrough. Two considerablerisein importantadvantagesare amperage at a given voltage. thereby gained usingthe This in turn requires that combinationcarbonfelt the voltage be decreased to and thin final cover: maintain a constant (I) Betterthrowing amperage.Asthis power intointernal continues, more and more cornerssuchasin plating occurs in the cover 0-ring grooves. and less occurs on the part (2) Less tool overheating requiringatsome point with solutions plated replacement of the cover, at high voltages and, sometimesseveraltimes. therefore,higher Replacement of the cover is possibleplating usually donewhenthe times. voltage has been reduced to half of the starting voltage. Cost is high and absorbency Replacement of the cover is and purity are excellent. ordinarily done by quickly takingofftheold OrlonSpecial Usedforlowthickness Scotchbriteand applying Purpose deposits (0.001 inch or less) newmaterial,pre-soaked Final where an as plated surface is with plating solution. This Cover desired that will be brighter eliminatestheneedto thanonestartedwith. prepare (clean, etch, etc.) There is some sacrifice of thesurface for additional qualityofdepositand p'ating.Costis moderate adhesion. and wear resistance is good.. BonnetCombi- PellonSpecial Verythinwear resistant Usedmoderatelyfor Purpose coverusefulforplating Materialnation preparatoryand plating Combi- smallI.D.'s,grooves,etc. tools.Moderateincost, nation where conventional covers wearability,and purity. Cover cannot be used. Absorbency Highinabsorbency. Not is poor. recommended with certain preparatoryandplating Plating tools and their covers can often be solutions.Referto used for a number of successive operations instruction manual. without any maintenance being required. When Carbon Special Applieddirectlyonthe plating tool covers become noticeably dirty or Felt Purposeanode andthencovered worn, replace them. with a thin final insulating Plating tools with clean and unworn covers, cover.Thecarbonfelt which will be used the next day, may be tightly serves as an extension of the wrapped in a clean plastic sheet or bag. Plating anode,i.e.,theoutside ,ols that will not be used for several days surface of the anode. The should be re-covered. Plating solution remaining felt is conductive enough to in the covers can be squeezed out and filtered carry plating current, but for reuse. 14.37 A MACHINERY REPAIRMAN3 & 2

PREPARATION OF ANODESFOR THE ELECTROPLATINGPROCESS

STEP-BY-STEP WRAPPING OF SCC AND SCG SERIES ANODES

USED FOR PLATING OUTSIDE DIAMETER SURFACES

PREPARATION OF COTTON BATTING

Cut a piece of cotton batting largeenough 2 to cover the concave side of the anodeto be wrapped. It is important thatthe cotton fibers run along the longest dimensionof the pad. This pad can be splitinto two layers for use on smaller anodes (picture1). Thickness of the cotton usedmay vary according to the application. Experience has shown that 3/16" thickness workswell 3 7,1 4 for the average application.

MOLD COTTON TO ANODE

Mold the cotton to theconcave side of the anode (picture 2).

FASTEN TUBEGAUZE 5 Cut a suitable size of tubegauze (atleast twice the length of the anode) and sliphalf the tubegauze over the anode andcover (picture3). The remaining half ofthe tubegauze is then twisted (picture 4)and slipped over the anode. Twolayers of tubegauze cover are thus provided, theends of which are secured with rubber bandsor

25,451 tubegauze ties around the base Jf the Dalic Plating Solution flow tube (picture 5).Cut a hole in the tubegauze for the Da lic tool handle and insert the handle (pictures6 and 7). The finished tool shouldhave a smooth concave surface (picture 8).

14-38 Chapter 14METAL BUILDUP

STEP-BY-STEP WRAPPING OF AC, WC AND RF SERIES ANODES

USED FOR PLATING INSIDE DIAMETER AND FLAT SURFACES

PREPARATION OF COTTON BATTING

Cut a piece of long-fiber cotton batting about one inch wider than the length of the Valk anode and six to eight timed onger than the diameter. Split the cotton to about 3/32thickness sonthat the final cover thickness after rolling will be 3/16. Lay the cotton on a table and wet 10 the anode with water so that it will adhere to Uend of the cotton (picture 9).

FOLD ENDS EVENLY

Fold the protruding end of the cotton evenly over the tip of the anode (picture 10).

, WRAP TIGHTLY

12 Wrap the cotton around the anode tightly by rolling from one end to the other. Feather the ends of the cotton so that the long fibers can be intertwined (picture 11).

TUBEGAUZE SECURES COTTON WRAP

The application of tubegauze provides maximum wear 28.458 resistance and prevents cutting through on sharp edges. Apply the tubegauze as on a finger (picture 12). The finished wrapping should be near and co npactth no bulges or thin spots (picture 13).

STEP-BY-STEP WRAP1. .: FG AND FF SERIES

USED FOR PLATING ", LA I" AND OTHERSURF ,crs FOLD COTTON %IND Atif t E 14 The long-fiber cot on padt'..); FG and FF anodes should be cut tor ;,i.tea 1/2,1,ap around the anode. Place the anode ot, the rytton / mg sure that the length of the cotton fibel. 1.1ni Arection of the long side of the anode (plebs. 4). d the cotton evenly around the anode and kee, 'tom surface smooth (picture 15).

INSERT INTO TUBEGAL7E

17 Hold...the wrapped anode by the bottom to keep the cotton smooth, insertI. into a pieceortubegauze(I. appropriate size (picture 16). Secure the ends of ma 'ubegauze tightly by twisting them and binding them with rubber bands co tubegauze ties (picture 17).

CUT HOLE FOR HANDLE

Cut a hole in the tubegauze largo enough to law/ the Dalic tool handle Into the anode (picture 18). The fully wrapped FG or FF anode should have a smooth oven pad ofcotton on the bottom, securedtightlyt,ythe 11 tubegauze (picture 19).

14-39 453 MACHINERY REPAIRMAN 3 & 2

STEP-BY-STEP WRAPPING OF SCC AND SCG ANODES

WITH SCOTCAIBRITE, DACRONFELT AND SIMIL.`4R MATERIALS

USED FOR VI-ATING OUTSIDE DIAMETER SURFACES

PREPARA '; ON OF SCOTCHERITE

Cut a pie. .f Scotchbrite 1/4-1/2" wider 20 21 than the anode and long enoughto cover the concave side of the anodeand partway up the end. Punch holes for.ouegauze ties (Picture. 20'.

MAIN ?ES

r. 10.11IMINI.O.. Cut tut, :.3 Dacron is best) as 22 Dorn, 23 shown (Pie , 28.459 TIE COVER TO OOL

Secure cover to tool with ties (Picture23). It may Iv: ..lecesary to makea cover with "e,tb- h some applicationswhere a more ( )ver is required.

SI LP-BY-STEP WRAPPING OF FG, FF AND SOME SPECIALANODES WITH SCOTCHBRITE, DACR.ONFELT AND SIMILAR MATERIALS

24 USED FOR PLATING FLAT AND OTHER SURFACES

PREPARE SCOTCHBRITE ANDTIES

Cut a piece of Scotchbrite 1/4-1/2"wider than the anode and long enoughto cover the working surface and extendonto the top. Punch holes and make tubegauzeties (Picture 24).

TIE COVER TO TOOL 25 28.460 secure cover to tool with ties(Picture 25).

14-40 '1 Chapter 14METAL BUILDUP

STORAGE AND SHELF LIFE Careful masking includes: OF SOLUTIONS 1.Careful cleaning of the surface before The shelf life of the majority of solutions is tape is applied. unlimited. Each manufacturer can be consulted forspecificinformation. As a general 2.Pressing in tape where a second layer of solutions should be stored at room temperaltio, tape rises to cover a preceding layer of tape. away from light. Excess cold, in storage transit, may lead to"salting out,"thatis, 3.Applying vinyl tape on surfaces such as formation of solid crystals at the bottom of the I.D.'s with no tension, since vinyl tape tends to container. These solutions may be restored to spring back. full effectiveness by heating to approximately 140°F and stirring until all salted out material is Vinyl tapes are ordinarily used for most redissolved. solutions. However, there are exceptions listed Used plating solution should be returned to by individual vendors. Consult your instruction used plating solution bottles along with a log of manual for particular solutions where it cannot the ampere-hours passed through the solution. be used. This will provide some idea of how heavily the solution has been used. The used solution is best Use aluminum tape on demanding masking 'Bed on less critical applications requiring lower jobs such as when using corrosive solutions, thicknesses of deposits. when plating with solutions that develop heat, A small percentage of dilution of solutions and when masking difficult areas such as I.D.'s. (from rinse water on the part or evaporation of Aluminum tape has an excellent adhesive and is water while in use) will have no effect on the strong and ductile. It will stay when carefully solutions.Whendilutionreaches 25% the pressed down. Vinyl tape may then be used on solution should be discarded. top, and it will stay better since it is on a fresh, clean surface.

MASKING A masking technique _hat offers a number of advantages is to mask with aluminum tape and Masking performs several functions in the then mask off a larger area with a nonconductive electroplating process: It prevents plating from tape such as vinyl. A 1/8 to 1J4,-inch band of being applied on areas where it is not wanted. It aluminumtapeis --- thus -1`texposed. The gives a definite size area that is being plated aluminum tape,being conductive,willina which permits more accurate thickness control. minute or so start taking plating. The first traces Itreduces waste of metal from the plating of burning and high buildup will then occur at solution. It reduces possibility of contaminating thenonconductivemaskededgeonthe the solution. aluminum tape. The area of interest, therefore, will have no buildup and is less likely to be Masking tapes are generally used to mask off burned at the edges. areas immediately adjacent to the area being plated. The materials used include vinyl tape, Large areas occasionally must be masked off polyester tape, aluMinum tape and copper tape. to prevent corrosive solutions from attacking the Absorbent tapes, such as painter's masking tape, part and to prevent solution contamination. In should not be used since they can lead to cross thesecases,tapes areused on immediately contamination of the solution. adjacent areas; areas farther away are masked with(1)"Contact Paper" which comes in Masking must be done more carefully when 18-inch wide rolls, (2) quick drying acrylic spray a corrosive solutionis used on reactive base paints, (3) vinyl drop cloth, or (4) "Orange materialor when considerable heatwillbe Paint" which is a tough adherent, heat resistant developed in plating. brush-on type paint. MACHINERY REPAIRMAN 3 & 2

SETTING UP JOBLONGER oralloywill be obvious, such RANGE PREPARATIONS as cadmium would be used to touchup a defective cadmium deposit. in these This section deals with howto properly cases, if there is a choice of solutions, make the longer range preparationsto carry out onlythe a job. It includes recommendations on selecting selectionof the proper and assuring that the specific solution remains. Thereare proper solutions, power other cases where a particular metalor pack, preparatory tools, platingtools, etc. are alloy is not specified or obvious such available. The material is arrangedin a step by as in salvage or repair. Tables 14-4, stepmannerdevelopedbypastpractical experience. 14-5, 14-6, 14-7 and 14-8 have been It prepared to assist in both instances. is assumed that a basic installationis Review these tables carefully before availableincluding a power pack.Steps 1 making a selection. through 7, however',can be used to select an appropriate installation includinga power pack or to assure that an appropriate installationhas Step #3Calculate amp-hours using formula 1, been purchased. page 14-65.

Step #1Obtain necessary information on job Step #4Decide on the general approachto the including: plating job: a. Number of parts to be done. b. Material on which deposit willbe a. Whether the part will be rotated, applied. In mostcases, it will be or whether the tool will 'De moved the material from which thepart is by hand. made. If the part, however, has had b. Whetherthesolutionwillbe a surface treatment such asan pumped or dipped. electroplate,carburizing,etc., platingisto be applied on the Step #5Decide on what type of plating tool surface material and not what is you will use, whether a standard tool underneath. or specialtool.If youwill use a c. Area to be plated; that is, havea specialtool, determine the design. concrete idea of size and shape of area to be plated. (See figures 14-15, 14-16, and 14-17.) d. Purposeandrequirementsof deposit; thatis,why coating is Step #6Based LH;platingtool to be used, beingappliedand whatitis determinecontactareaifnot expected to do. determined in Step #5. e. General idea of what is adjacent. f. Thickness of deposit required. Step #7Based on contactarea, determine the plating current if not established Step #2Selecting plating solution to be in used. Step #5. Use formula 4,page 14-66. This is,in most cases, an extremely importantstep.Properselection Step #8 Determinetheplatingtime using assures that the desired results will be formula5, page 14-66. Ifthe obtainedwith maximum ease and solution will be dipped for, doublethe minimum cost. Inmany cases, the plating time. pure metal or alloy will have already been chosen either bya specification Step #9 Determinetheamount of plating or blueprint; in other cases, the metal solution necessary, using formula 6,

14-42 4, Chapter 14-METAL BUILDUP

Table 144.-Characteristics of Solutions and Deposits

Plating Code Normal Ease in Ease in Corrosion Special Solution Maximum Using Reactivating Tendency Toxicity Thickness Solution Deposit in Base Problems In One Materials Layer (In.)

Antimony 2000 Very Difficult Low Toxic Metal Bismuth 2010 Very Difficult Low None Cadmium 2020 .007 Easy Very Easy Some Toxic Meal Cadmium 2021 .005 Easy Very Easy Low Toxic Metal Cadmium 2022 .007 Very Easy Very Easy Low Toxic Metal Cadmium 2023 .005 Easy Very Easy Low Toxic Metal Chromium 2030 .002 Difficult Very Difficult Low Toxic Metal Chromium .2031 .0005 Very Difficult Very Difficult Some Toxic Metal Cobalt 2043 .008 Easy fy'lrage Low NGne Copper 2050 .015 Very Easy Very Easy High Very Acidic Copper 2051 .006 Average Difficult Low None Copper 2052 .004 Easy Difficult Low None Copper 2054 .015 Easy Easy High Very Acidic Copper 2055 .012 Easy Easy High Very Acidic Iron 2061 .007 Average Average Low None Lead 2070 .007 Very Easy Easy Low Toxic Metal Lead 2071 .007 Very Easy Easy Low Toxic Metal Nickel 2080 .007 Average Average Low None Nickel ?185 .015 Easy Easy Low None Nickel 2086 .007 Average Average Low None Nickel 2088 .007 Average Average Low None Tin 2090 .007 Very Easy Easy Low None Tin 2092 .007 Very Easy Easy Low None Zinc 2100 .003 Easy Easy Low Toxic Metal Zinc 2101 .008 Very Easy Very Easy Low Toxic Metal Zinc 2102 .006 Very Easy Very Easy Low Toxic Metal Zinc 2103 .012 Very Easy Very Easy Low Toxic Metal Gallium 3011 Average Low None Gold 3020 .007 Easy Very Easy Low Has Cyanide Gold 3021 .007 Easy Very Easy Low Has Cyanide Gold 3022 .007 Easy Very Easy Low Has Cyanide Gold 3023 .001 Easy Very Easy Low Has Cyanide Indium 3030 .010 Very Easy Very Easy Low None Palladium 3040 .005 Easy Average Low None Platinum 3052 .005 Average Easy Low Very Acidic Rhenium 3060 .0001 Very Difficult Low Very Acidic Rhodium 3072 .002 Difficult Average High Very Acidic Rhodium 3074 .001 Difficult Average High Very Acidic Silver 3080 .005 Average Easy Some Has Cyanide Silver 3081 .007 Average Easy Some Has Cyanide Silver 3082 .010 Very Easy Easy Low Has Cyanide Silver 3083 .010 Very Easy Easy Low Has Cyanide Nickel-Cobalt 4002 .007 Average Average Low Toxic Metal Tin-Indium 4003 .007 Very Easy Very Easy Low Toxic Metal Tin-Lead-Nickel4005 .015 Very Easy Very Easy Low Toxic Metal Cobalt-Tungsten 4007 .005 Difficult Difficult Low Toxic Metal Nickel-Tungsten 4008 .005 Difficult Difficult Low Toxic Metal Babbitt SAE 11 4009 .010 Very Easy Very Easy Low Toxic Metal Babbitt -Soft 4010 .010 Very cisy Very Easy Low Toxic Metal Babbitt-Navy #24011 .010 Very isy Very Easy Low Toxic Metal

14-43 Table 14-5.-Data on Solutions

Plating Code Metal Fac- Current Plating Yield % Solution Cost Solution Con- for Density Rate Required S per tent A/In2 In/Hr per Cu. In. G/L Nor. Avg. A FF71Tiii. Cu. In Liter Max. Max. Lit. Gal. Price Antimony 2000 80 .008 5 2.5 .062.031 50 2.7 .72 Bismuth 2010 70 .008 128 3 1.5 .038.019 50 4.6 Cadmium 2020 160 1.21 287 .007 12 6 .172.086 40 Cadmium 2021 2.2 ,56 109 70 .007 4 2 Cadmium .L.57 .029 50 4.1 1.07 216 2022 110 .007 7 3.5 .100.050 50 2.6 .68 Cadmium 2023 100 139 .007 8 4.0 .114.057 50 Chromium 2030 2.8 .75 150 30 .137 12 6 .009 Chromium .005 7 56.014.8 2,974 2031 150 .120 4 2 .003.002 5 15.7 Cobalt 2043 80 4.15 874 .020 14 7 .070 Copper .035 33 5.4 1.44 242 2050 60 .013 6 3 .046.023 50 4.9 1.29 94 Copper 2051 60 .013 7 3.5 .054.027 66 3.7 Copper 2052 60 .97 98 .013 7 3.5 .054.027 Copper 66 3.7 .97 102 2054 60 .013 9 4.5 Copper .069.035 50 4.9 1.29 2055 145 .013 25 12.5 Iron .192.096 25 4.1 1.07 2061 50 .018 116 12 6 .067.033 12.5 20.6 Lead 2070 100 5.45 864 .006 4 2 .067.033 Lead 2071 50 3.7 .98 98 100 .006 4 2 .067 rr, Nickel .033 3.7 .98 106 2080 110 .021 12 6 Nickel .057.029 16.6 8.0 2.1 2085 50 .015 338 14 7 .093.047 50 Nickel 2086 5.8 1.54 160 40 .025 10 5 .040 Nickel .020 37.5 9.7 2.57 445 2088 55 .021 12 6 Tin 057.029 30 8.8 2.34 2090 BO .007 4 2 .057.029 50 Tin 2092 3.0 .79 172 30 .007 4 2 .057 Zinc .029 50 3.0 .79 166 2100 100 ,011 6 3 .055.027 50 2.3 Zinc 2101 75 .62 56 .011 14 7 .127 Zinc .064 50 3.1 .82 75 2102 100 .011 14 7 .127.064 40 2.9 Zinc 2103 80 .77 75 .011 14 7 .127 Gallium .064 50 2.q .77 84 3011 30 .015 3 1,5 .020.010 50 6.5 Gold 3020 100 1.71 .006 3 1.5 .050.025 50 Gold 3021 6.3 1.67 98 .006 3 1.5 .050 Gold .025 50 6.5 1.71 3022 90 .006 3 1.5 .050.025 50 7.0 Gold 3023 25 1.86 .007 .5 .25.007.004 50 Indium 3030 60 25.3 6.7 .009 4 2 .044.022 50 Palladium 3040 4.0 1.05 30 .017 6 3 Platinum .035.018 50 13.1 3.47 3052 50 .150 12 6 Rhenium .008.004 20 35.2 9.3 3060 20 .750 6 3 .001.0005 33 52.213.8 Rhodium 3072 50 .030 6 3 .020.010 60 Rhodium 3074 20 6.8 1.80 .030 4' 2 .013.007 50 Silver 3080 20.4 5.4 190 .005 8 4 .160 Silver .080 33 2,7 .72 3081 100 .005 2 1 .040 Silver .020 50 3,4 .91 3082 100 .005 5 2.5 .100.050 50 3,4 Silver 3083 100 .91 .005 5 2.5 .100 Nickel-Cobalt .050 50 3.4 .91 4002 84.2 .030 12 6 .040.020 16.6 10.4 Tin-Indium 4003 73.4 2.75 361 .008 4 2 .050.025 50 Tin-Lead-Nickel 4005 84 3.3 .86 265 .006 3 1.5 .050.025 Cobalt-Tungsten 4007 40 3,8 1.01 158 80 .020 12 6 .060.033 12.5 14.5 3.83 640 Nickel- Tungsten 4008 123 .025 12 6 .048.024 10 11.9 Babbitt SAE11 4009 )0 .006 3.13 487 1 1 .017.017 33 Babbitt-Soft 4010 4.5 1.19 245 8c .006 1 1 .017.017 33 4.5 1.19 Babbitt-Navy #2 4011 .006 245 1 1 .017 .017 33 4,5 1.19 231

14-44 Chapter 14METAL BUILDUP

Table 14-8.Properties of Deposits

Deposit Code Hardness Structure Ductility Adhesion Knoop DPH 8HN R Properly Plated

Antimony 200D 47 4D 38 -- Very Poor Poor Bismuth 2010 19 16 15 -- Very Poor Poor Cadmium 2020 25 21 20 -- No Defects Good Excellent Cadmium 2021 23 20 19 -- Micro Porous Fair Fair Cadmium 2022 30 26 25 -- No Defects Good Excellent Cadmium 2023 27 23 22 -- Micro Porous Fair rair Chromium 2030 681 584 553 54 Micro Cracked Not Coherent Fair Chromium 2031 908 778 709 63 Some Stress Cracks Very Poor Fair Cobalt 2043 514 441 418 45 No Defects Fair Excellent Copper 2050 165 141 134 -- No Defects Excellent Excellent Copper 2051 249 213 202 (14) No Defects Poor Fair Copper 2052 244 209 198 13) No Defects Poor Fair Copper 2054 206 177 16 8 5 ) No Defects Good Good Copper 2D55 260 223 211 16) No Defects Fair Good Iron 2061 595 510 483 50 Some stress CracksVery Poor Excellent Lead 2070 7 6 6 -- No Defects Excellent Good Lead 2071 7 6 6 -- No Defects Fair Good Nickel 2080 530 454 430 46 No Defects Very Poor Excellent Nickel 2085 683 585 554 54 Micro Cracked Very Poor Fair Nickel 2086 326 279 264 27 No Defects Excellent Excellent Nickel 2088 400 343 325 35 No Defects Fair Excellent Tin 2090 8 7 7 -- No Defects Excellent Good Tin 2092 9 8 8 -- No Defects Excellent Good Zinc 2100 48 41 39 -- Micro Porous Fair Good Zinc 2101 61 52 49 -- No Defects Good Excellent Zinc 2102 63 54 51 -- No Defects Excellent Excellent Zinc 2103 55 47 45 No Defects Excellent Excellent Gallium 3011 M.M. ..M. Gold 3020 148 127 120 -- No Defects Fair Excellent Gold 3021 140 12D 114 -- No Defects Fair Excellent Gold 3022 143 123 117 -- No Defects Fair Excellent Gold 3023 140 120 114 -- No Defects Fair Exce1lent Indium 303D 2 2 2 -- No Defects Excellent Excellent Palladium 3040 436 374 354 38 Micro Cracked Not Coherent Fair Platinum 3052 550 471 446 47 No Defects Fair Good Rhenium 306D MMOO. MOOMM Rhodium 3072 927 795 718 64 Some Stress CracksVery Poor Fair Rhodium 3074 950 814 729 64 Some Stress CracksVery Poor Fair Silver 3080 110 94 89 -- No Defects Very Poor Fair Silver 3081 163 140 133 -- No Defects Poor Good Silver 3082 80 69 65 -- No Defects Poor Excellent Silver 3083 142 122 116 -- No Defects Poor Excellent Nickel-Cobalt 4002 543 465 441 47 No f49ects Very Poor Excellent Tin-Indium 4003 11 10 9 -- No Defects Excellent ;Jood Tin-Lead-Nickel 4005 9 8 8 -- No Defects Excellent Excellent Cobalt-Tungsten 4007 630 540 512 52 Micro Cracked Very Poor Good Nickel- Tungsten 4008 620 531 503 51 Some Stress CracksVery Poor Good Babbitt SAE 11 4009 25 21 20 -- No Defects Fair Good Babbitt-Soft 4010 22 19 18 -- No Defects Fair Good Babbitt-Navy #2 4011 23 20 19 -- No Defects Fair Good

1445 (I t) Table 141.-CommonlyUsed Data

Plating Code Factor Platilq\lolAL Solution Current Solution Minimum Maximum Maximum Procedures Density Required Small Tools Recommended large Tools \on A/In2 per and Areas Use and AreasNew fobs Nor. Aug Cu. In, Amp Hrs. Per Max lit, Gal. liter Gal, Antimony 2600 .008 7 18 5 2.5 2,1 .72 29.5111.6 Bismuth 2010 ,008 2 10 3 1.5 4.61.21 11.4 66.0 Cadmium 2020 .001 6 20' 6+1.1 12 Cadmium 6 2.2 2021 .001 .56 31.6 5 20 119,6 5+1.1 4 2 Cadmium 2022 4.1 1,07 .007 1 17.3 65.4 22 7+1.1 1 Cadmium 3,5 2,6 2023 .007 .68 21.1' 102.8 6 20 6+1.1 8 4.0 2.1 .15 24,1 93.4 Chromium 2030 ,131 8 25! 8+1-1 Chromium 12 6 2031 ')k, 14,8 .120 4 24,4 92.4 10' Ste 6.3.7 4 2 '' 4.15 76.4289.0 Cobalt 2043 .020 it 25 See 6.3.8 14 1 .d 1.44 36.8139,2 Copper 2050 ,013 3 12 3 +1-1 Copper 6 3 4.9 2051 .013' 1.29 26.6 1 20 100.5 7+1-1 1 Copper 2052 3,5 3.1 :013 4 .97 18 35.4-'134.0 4+1.1 1 iNker 2054 3,5 3.1 .013 5 .91 35.4 15 134.00 5+1-1 9 Copper 4.5 4.9 2055 .013 1.29 26.6 100.5 6 18 6+1.1 25. 12.5 4.1 1.01 32.1 121.4 Iron 2061 .018 6 20 6+1.1 12 6 20.E 5,45 8.1 33. ',tad 2010 .006 6 20 6+1.1 lead 4 2 3.1 .98 2011 ,,006 8 16,1 61.1 20 8+1.1 4 2 3.7 .98 16.1 61.1 Nickel 2080 .021 8 25 Nickel See 6.3.17 12 2085 6 8.02,1 .015 6 26.4 99.9 20 6+1-1 Nickel 14 1 2086 .025 5,8 1.54 25:7 7 25 97.3 Nickel See 6,3.19 10 5 2088 9.1 2,57 ,021 8 ,25.7 97.3. 25 See 6.3.20 12 6 8.8 2,34 23.1 89.9 Tin 2090 .001 5 20 Tin 5+1-1 4 2092 2 3.0 . 01 .19 23.4 6 25 88.6 6+1.1 4 2 3,0 .19 23.4 88.6 Table 141.-Commonly Used Date-Continued

Plating Code Factor Plating Voltages Current Solution Maximum

Solution Minimum MaximumProcedures Density Required Recommended

Small Tools Large Tools on A /In2 per Use

and Areas and Areas New Jobs Nor.Avg, Cu. In. AIHrs. Per

Max lit, Gal, Liter Gal. /in 2100 .011 8 20 8+117 6 3 2.3 .62 47,1170.1

Linc 2101 .011 9 20 9+1.2 14 7 3.1 .82 35.3 133.6 lint 2102 .011 9 20 9+1.2 14 1 2.9 .77 311142.5

2103 .011 7 11 7+1.2 14 7 2.9 .77 37.6 142.5

Gallium 3011 .015 12 - 3 1.5' 6,5 1.71 23,2 87.9

Gold 3020 .006 4 20 See 6,3.21 3 1.5 6.3 1.67 9.5 35.9

Gold 3021 .006 4 20 See 6,3.27 3_ 1,5 6.5 111 9,3 35.1 Gold 3022 .006 4 15 See 6.3.28 3 1.5 1,0 1.86 8.5 32.3

Gold 3023 .001 4 10 See 6,3.29 .5 .25 25.3 6.1 2.8 10.5

Indium 3030 .009 8 25 See 6.3,30 4 4.0 1.05 22.5 85.3 Palladium 3040 .017 4 14 4+1-1 6 13.1 3.41 12.9 49.0 Platinum 3052 ,150 3 10 See 6,3,32 12 35.2 9,33 42.1 161.5

Rhenium 3060 .150 6 3 52.213,84 152.5 571.3 Rhodium 307L ,C30 4 15 1+1.1 6 3 i.81,80 44,1 167,1 Rhodium 3074, ,030 3 12 3+1.1 4 2 20,4 5.4 14.1 55.1

Silver 3080 .005 8 20 8+1.1 8 4 2.7 32 18,4 69,1

Silver 4 3081 .005 10 4 +. -1 2 1 3.4 .91 14.5 55.0 Silver 3082 .005 5 16 5+1-1 5 2.5 3.4 .91 14.5 55.0

Silver 3083 .005 5

Nickel-Cobalt 4002 .030 8 25 See 6.3,39 12 6 10.1 2.75 28,9 109.2 Tin - Indium 25 - R.Q3_,Q08 8 4 J , 3.3 .85 24.5 92.9 Tin-Lead-Nickel 4005 .006 5 15 5+1.1 3 1.5 3.8 1.01 15.6 59,2

Cobalt-Tungsten4007 .020 10 25 See 6,3.41 12 6 14.5 3.83 13.1 52.2 lickel-Tungsten 1008 ,02 __See 6,3.42 11.9 3.13 21.1 798

Babbitt SAE 11 4009 .006 3 15 See 6.3.43 1 1 4.5 1.19 13.2 50.0

1Q1 .006 3 15 Sae 6.3.43 1_ 1 4.5 1,19 13.2 50.0 Babbit'vy q 4011 .006 3 15 See 6.3.43 1 1 4.5 1,19 13.2 50.0

Aeon MACHINERY REPAIRMAN 3 & 2

Table 14-8.Solutions Used for Salvage Sol ution Code BHN Ductility Normal Ease MaximumSolution Maximum in PlatingCost $ Build Up Plating Speed PerI n. 3 One In . /Mr ayer- Inches

Chromium 2031 709 Very Poor .0005 Very .003 Difficult 874.00 Nickel 2085554 Very Poor .015 Easy .093 160.00 Chromium 2030 553 Not Coherent .002 Difficult .0092,974.00 Cobalt- 4007 512 Very Poor .005 Tungsten Difficult .060 640.00 Nickel - 4008 503Very Poor .005 Tungsten Difficult .048 487.00

Nickel 2080430 Very Poor .007 Average .057 338.00 Cobalt 2043 418 Fair .008 Easy .070 242.00 Nickel 20(58 325 Fair .007 Average .057 Nickel 2086 264 ExcEllent .017 Average .040 445.00 Copper 2055 211 Fair .012 Easy .192 116.00 Copper 2052 198Poor .004 Easy .054 102.00 Copper 2050 134 Excellent .015 Very Easy .046 94.00 Silver 3083 116 Poor .01'J Very Easy .100 391.00 Zinc 2102 51 Excellent .006 Very Easy .127 75.00 NOTE: Code 2085, 4007, and 4008 required after plating. deposits should be ground ifmachining is Code 2080, 2043, 2088, and2086 deposi,:s should be ground, but can be machinedbut with difficulty and 2055. 2052, 2050, 2102 and high tool wear. Code 3083 deposits are easilymachined.

page 14-66. Multiply by some factor Step #11 Determine if some solution will be covers to beused on all inadvertently preparatory and plating tools. lost. Factors vary from 1.5 toas much as 4. Factors will be found on solution Step #12 Determine masking bottles. (See figure 14-18.) required. Two examples of the planning Step #10 Determinepreparatory and preplate procedure usedonactualjobsfollowbelow.This solutions required using table 14-9. information is furnished from the Determine type of tools to be Dalic Selective used Plating Instruction Manual foryou to use as a withthesesolutions usingfigures guideline. Consult your particular 14-13 and 14-14. instruction manual before any platingoperation. 14-48 Chapter 14METAL BUILDUP

a k Milk

r't Kra VIt to i , RUC Ill ;Pal 210

um Weis

i*/""41".';."7.75..;.v.:::.. 28.466 Figure 14-18.Platir9 soNtions.

EXAMPLE #1: e. Generalideaofwhatis adjacentPart overii has a 3-ft Step #1Information on the job. O.D. and a maximuh, thickness of about 1 inch. Numerous turbiiu a. No. of parts-1 blades are at the O.D. b. Base Material Steel f. T!,icknessofdeposit c. Areatobeplated-1" requiredD'ameter after t. sing up long x 3.500 + 0.000bore in I.D.by grindingis1..5015. A turbine wheel. plating thickness of 0.001 inch will bring bore to middle ')f desire° d. Purpose of depositRepair worn tolerance. I:D. Color match important. Good hardness, adhesion and cohesion Step #2Select plating solutiontc. be used. required. Cobalt 2043 meets all requir:,nents. MACHINERY REPAIRMAN 3 & 2

Table 14.9. Solution and Deposit Properties

Solution Code Applications

Chromium 2031 Used' occasionally as-ail overlaya few ten-thousandths inches thick on nickel or n.obaltwhere a little more wear resistance is desires, suchas on hydraulic piston rods.. Never used alone fnrsalvage.

Nickel 2085 Used extensively for salvage andrepair of aluminum, cast iron, and steel parts. Works well under roller bearings, riding against babbitt bearings,etc. Not used in cases where there isextreme shock such as on cutting ends of punches, etc.

Chromium 2030 Very seldom used for salvage.

Cobalt- 4007 Used occasionally for highwear applications, partic- Tungsten ularly at high temperature, i.e.,up to approximately 10000F. Maximum thickness approximate12,.005 inches.

Nickel 2080 Used of, where a good combination ofwear resistance, corrosion resistance, and toughnessis desired. Used primarily on steel, stainless steel,nickel, etc.

Cobalt 2043 Used often where a good combination,of we -esistance, and toughness is desired. Used primarily orsteels stainless steel, nickel, etc. Excellent culor match with steel and stainless steel.

Nickel 2088 & Used often where maximumductility a ...'corr. qion 2086 protection are desired along withsc..2 hrrdness. Copper 2055 Used occasionally for high-buildupson smaller areas where maximum plating speed is impertant. Adhesion and coherence not quite as goodas Code 2050. Copper 2052 Used occasionally for buildupsup to Zs'4 incies on aluminum, steel, cast iron, and zinc,,articularly where it is difficult to mask andprevent attack by other solutions.

Copper 2050 Used extensively on steel,copper, cast iron, nickel, and stainless steel particularlyin high buildups. Often overlaid with nickelor cobalt for extra wear or corrosion resistance.

Silver 3083 Used occasionallyon worn surfaces where the plaring must be hand-worked to meet finaldimensionai recuire- ments. Is hard enough for most applications,but is soft enough to be easilyscraped or sanded.

Zinc 2102 USEA extensively on aluminumand zinc particularly in high buildups.

14-50

/Po4, Chapter 14METAL BUILDUP

Step #3Amp-hr required. short that turning the part in a lathe orpumpingthesolutionisnot A - 3.14 DL - 3.14 x 3.50 x 1.30 - 11.0 necessary and the tool will be moved Arno - Fx A x T- 0.020 x 11 x 10 - 2.2 by hand.

Step #4( eneral approach. Step #9Plating solution required. The small area, amp-hr, and thickness involved suggest that (1) a special tool Liters - Q(L) x T(I) x A - 5.4 x 0.0010 x 11 is not required and (2) that sol ition - 0.059 need not be pumped. This will be justified in the following steps. The Thisobviouslyisnot enough to part will be cleaned, etched, rinsed, thoroughlywetthecover.Itis etc. over a drain and then, being light estimated that 1 liter will be sufficient enough,willbeplacedovera for the purpose. 14" x 17" collecting pan. A hole in thecollecting panwilldirectthe solution b acktothesclution Step #10 Preparatoryand preplatesolutions container. The solution container is and tools. large enough to hold all the solution, butsmall enough to have enough a. Code 1010, 1022, 1023, and 2080. depth of solution to thoroughly wet all of the plating tool. b. Tools:AC-5.These,although relatively small, give a 1/2" x 1" Step #5Plating tool to be used. c on t actareaandshouldbe satisfactory. A RE-30 tool with a 1/4" thick cover will just match the internal diameter. c. Quantityofsolutionrequired: Approximately 0.1 liter for each. Step #6Plating tool contact area. This amount, when a small beaker is used, should thoroughly wet the cover. Although tool with cover just matches the I.D., pressure on the tool cover will compact it and lead to perhaps Step #11 Covers to be used. 50% contact area,i.e.,5.5 square inches. Preparatory tools: Cotton batting and cotton tubegauze. Step #7Plating amperage. Platingtool:Cottonbatting and cottcn tubegauze, since the cover is Plating Amps - CA x ACD - 5.5 x 7 - 38.5 purl. a ndinexpensive.Although cotton tubegauze is not wear resistant, Step #8Plating time. itshouldeasilyhold upin the 15-minute plating time. Amp-hr 2.2 PT(hr) - 0.057 hr Plating Amps38.5 Step #12 Masking. Doubletheplatingtimebecause solution will be dipped for. The total Aluminum tape and contact paper to plating time, therefore, is 0.114 hr or prevent the part from contaminating 6.84 minutes. The plating time is so the solution.

14-51 473 MACHINERY REPAIRMAN 3 & 2

EXAMPLE #2: Step #4General approach. Step #1Information on job. The ,'.it will be rotated ina lathe a. Number of parts-1 becF.,: ze a lathe is available. Solution b. BasematerialSteel withloose will also be wriped througha special metal spray from previous repair. tool. c. Area to be plated-7" long areaon 2.436 + 0.001 O.D.- 0.000 d. Purpose andrequirementsof Step #5Plating tool to be used. depositRepair loose fiton inner race of roller bearing. e. Althoughthepart isalarge A special tool will be preparedfor recirculating fan about 5 feet long copper plating since no standard tool and with a maximum O.D.of 3 feet,the area being plated is is available to cover the full 7" length. a The largest power pack available isa simple O.D. on a shaft. 60-35. f. Thickness requiredIt Planningondrawing55 was decided amperes, the Optimum Contact Area to machine off the metalspray was determined: coating which was obviouslyvery loose, leaving a gentletaper at MA edges.Aftermachining,the OCA = 55 diameter was 2.285". Thickness ACD = 18'3 requiredtherefore,is 0.152" in diameteror0.076" onradius. Sinceplating Since the length of the O.D. is 7",the willhaveto be contactlengtharoundthe stopped one or two timesfor machining to remove buildupat circumferenceshouldbe18'3or edges and improve the surface,a approximately 2.6 inches. A special total of approximately 0.100inch anode,therefore,will be prepared plating should be plannedon. about7 1/2"longx 2 3/8"wide Step #2 x 1 7/8" high. It will have a 1 1/2" Select plating solution to beused. radius (1/4" allowance for toolcover) placed in the 2 3/8"x 7 1/2" face. Copper 2050 will be usedbecause of Solutionwillbefedthrough an the high thickness required.Copper F-handle to a 1/2" hole in theanode, 2050 stays smooth to highthicknesses running n the 7" direction (capped and is easy to reactivatefor more off at ends) and P. en throughsix 1/8" plating. Machining will berequired holesdistribui A alongthe7" becauseof thehigh thickness of direction t.) the face having the radius. deposit to be applied. Thedeposit, therefore, after copper plating willbe machined 0.0005 inch undersizeon Step #6Plating tool contactarea. the diameter and then be platedwith 0.0005 inch of nickel 2085for color match. CopperNot required (determined in Step #5). Step #3 Amp-hr required. NickelIf an F-3 plating tool is used for nickel plating, the contactarea A= 3.14 DL = 3.14 x 2.436 x 7 = willbe3 1/2" x 1"alongthe Amp-hr (Cu) =FxAxT = 0.013 x 53.5 x 1000 = 696 circumferencewith a softpad. Amp-hr (Ni) =FxAxT= 0.015x 53.5 x 54.01 CA = 3.5 x 1 = 3.5sq in.

14-52 47.1 Chapter 14METAL BUILDUP

Step #7Plating current. b. Tools required. cz) CopperNot required (determined in 4 (F-2 or F-3) Step #5). c. Amount of solution required. NickelPlating amperage Plaiing Amps - CA x ACI) - 3.5 x 7 - 24.5 1010-1 liter (will be used severd, times) Step #8Plating time. 1022-1/2 liter (will be used once) Amp-hr 696 Copper PT (hr) - 12.7 Plating Amps 55 .323-1(willbeusedseveral times) Amp-hr 4.01 Nickel PT (hr) - - 0.164 Plating Amps24.5 2080-1/2 liter (will be used once) If solution is dipped for total nickel Step #11 Covers tp be used. plating, time would double, i.e., 0.328 hour.Theuseof an F-3tool, Preparatory toolsCotton batting and therefore, is justified and the solution cotton'tubegauze. neednot be pumped through the Copperplatingtool--White anode. Scotchbrite

Step #9Plating solution required. Step #12 Masking. Aluminum tape 2" and vinyl tape 2". Copper 2050 (gal)Q(G) x T(I) x A - 1.29 x 0.100 x 53.5 - 6.90 FINAL PREPARATION Sincealmostallsolutioncanbe caught for reuse, 7 gallons of copper Longer range planning should have assured 2050 should be sufficient. thatappropriateequipment,materials,and supplies are available to carry out the job. This Nickel 2085 (gal) - Q(G) x T(I) x A - 1.54 x section deals with the final preparations you .0005 x 53.5 - 0.041 should make just prior to plating. Nickel 2085 (liter) - Q(L)T(I) x A - 5.8 x .0005 x 53.5 - 0.155 FAMILIARIZATION WITT' Since an F-3 tool will be used to apply EQUIPMENT AND PROCILDURES nickel,0.155literwould not be sufficient to wet the tool and the area to be plated. Ai:proximately 1/2 liter Success in carrying out plating operations is is required. assured by quickly and knowledgeably carrying out the various steps. As the operator you Step #10 Preparatoryand preplate solutions should be familiar with the following: and tools. 1.The power pack and the position and a. To activate base material-1010, purpose of the various controls and meters. 1022, 1023, and 2080. To activate copper for more copper and the 2. How the base material should look at final nickel coating 1010,1023. various stages of preparation.

14-53 0 MACHINERY REPAIRMAN 3 & 2

3.What a good and bad deposit looklike as 3. Mask off the the plating is being applied. area to be plated. 4.If the part is to be rotated ina lathe or Some practiceis recommended when the turning head, set the equipmentis rpm to obtain optimum new,a new base materialis anode-to-cathode speed as given in table encountered, or a new plating solution 14-10. is to be If plating tool will be moved by hand,visualize used.In practicing ona new base material, the proper tool movement speed. shorter and longer operations should'be tried until the operator is certain when he is obtaining 5. When thesolutionplatesbetterat the desired appearance. In practicingwith a new temperatures higher than room temperature, solution, very high andvery low voltages should be used until the operator is preheat the part and the solution,as required, certain that he by a suitable means. Methods usedto preheat knows what a good deposit and baddeposit solutions include: (burned or otherwise) looks like. Ifpossible, the operator should run a plating test on a 1" X 1" a. Placing tightly capped bottles ina area using an AC-5 or similar size tool;the basin or tank of hot water. operator should be able to plate a good deposit b. Pouring solutions intopyrex or stain- at the volts and amps given in table 14-3and the "Plating Example." less steel containers and heatingover a range. c. Putting immersion heaters into the solution. DRAFT A FLOW CHART

SETTING UP THE EQUIPMENT A very valuable tool forany operation is a good plan. Figure 14-19 showsa recommended plan or flow chart which will help you conduct Set up the power packnear the work so it is the operation smoothly, and remindyou of all easilyaccessibleand the important elements of the youcanviewthe operation. instruments. Connect appropriate sizeoutput leadstothe power pack and connectthe PREPARE PART alligator clamp lead to the partor the lathe. FOR PLATING Wrap the tocls, makingsure the covers do not get dirty.

I.Inspect the area to be platedfor any Pourout signs of a foreign surface being sufficientsolutioninclean present such as containers. Set up the solutionpump and test an electr- gate, paint, scale, anodizedcoating, operate it. Soak the covered tools etc. Remove by suitablemeans such as vapor or as long as dry possible in their respective solutions(at least five blast,sandpaper,wirebrush,etc.In minutes). pit-Idling applicationspay particular attention to ensure that the bottom of the pit is clean. Arrange so everythingyou will use is handy. 2.Preclean, if necessary, thearea to be plated andthesurroundingareaswitha GENERAL SETUP quick-drying solvent that leavesno residue (such as trichlorethylene, perchlorethylene, etc.).This should assure that masking materialswill still Asthe stick and that solutions and operator,youshouldbeas tools will not come comfortable as possiole, particularlyon lengthy in contact with dirty, oily surfaces.The area to plating jobs. You can then be plated should look clean. concentrate your full attention on the job,you will not be diverted by

14-54 1; base Material- Cast Ir.r---TreiPTaTe-17 I.D, x 2' [Ong DepaRied- Nickel Code 2085 Thickness Recuiled- .003" Tool to Part Movement - Lathe 64 r.p.m. Plating Tool- Special, Covers 112 of Area Solution Su,lily- Pump Amp.Hrs, - 8.5 Erected Amps- 66 Step Operation Material is Po arity Visua Test What you are oo ingsfor

1 Preclean As required -- Clean until surface free of visible film', of oil,

grease, dirt and oxide films.

2 Electrocledn Cleaning & Deoxidizing 18 Forward No Water breaks after followinvinse. Code 1010

3 Rinse Clean tap water Thorough rinse of entire area. No water breaks.

4 itch No, 2 Etch Code 1022 12 Reverse Uniform etch of entire area. Dark gray color. Cast

iron grain structure visible.

5 Rinse Clean tap water Thorough rinse of entire area. No water breaks,

6 Desmut No. 3 Etch Code 1023 20 Reverse Uniform lightening to a light gray r,:lor. Will not

become any lighter. Some cast irons change their

grain structure.

1 Rinse Clean tap water, Thorough rinse of entire area. No water breaks.

8 Nickel Nickel Code 2080 8 then +1 to Forward Change of surface to a more nickel color, No darker Preplate approx. 13 burned areas.

9 Rinse Oft NO Clean tap water Thorough rinse of entire area. No water breaks.

10 Prewet Nickel Code 2085 Replacement of water on entire area with Nickel Code 2085,

11 Nickel Plate Nickel Code 2085 8 then +1 Forward Medium gray, matte surface.

to approx. 13

12 Rinse Clean tap water -- Thorough rinse of entire area. No water breaks.

13 la Neutralize Cleaning & Deoxidizing -- Replacement of water on entire area with Code 1010.

Code 1010

14 Dry As required -- Complete drying of surface,

Figure 14.19.Sample flow chart for setting up plating. MACHINERY REPAIRMAN 3 & 2

Table 14-10.-Plating Solution Data for Operators

Plating Code Factor Plating Maximum Anode to Temperature 0 F Solution Amp-Hrs. for Example Recommended Cathode Optimum O.K. .0001" Using Use Speed at on 1 in.2 AC-5 Tool Amp-Hrs. Per ft./min. Room Volts Amps Liter Gal. Temp.

Antimony 2000 .008 8 1.3 29.5 111.6 50 60-120 Yes, Bismuth 2010 .008 4 1 17.4 66.0 50 60-120 Yes Cadmium 2020 .007 8 5 31.6 119.6 75 60-120 Yes Cadmium 2021 .007 8 1 17.3 65.4 50 60-120 Yes Cadmium 2022 .007 16 2 27.1 102.8 50 60-120 Yes Cadmium 2023 .007 8 1.2 24.7 93.4 50 60-120 Yes Chromium 2030 .137 12 6 24.4 92.4 20 Chromium 60-120 Yes 2031 .120 6 4 76.4 289.0, 50 105 Yes Cobalt 2043 .020 13 5 36.8 139.2 25 60-150 Yes Copper 2050 .013 4.5 2.5 26.6 100.5 50 60-120 Yes Copper 2051 .013 10 3 35.4 134.0 50 60-120 Yes Copper 2052 .013 8 3 35.4 134.0 50 60-120- Yes Copper 2054 .013 8 3 2b.6 100.5 5U 60-120 Yes Copper 2055 .013 10 10 32.1 121.4 50 60-120 Yes Iron 2061 ,018 14 4 8.7 33. 50 60-150 Yes Lead 2070 .006 10 1.5 16.1 61.1 50 60-120 Yes Lead 2071 .006 12 1.2 16.1 61.1 50. 60-120 Yes Nickel 2080 .021 14 4 26.4 99.9 50 110-170 No Nickel 2085 .015 8 3 25.7 97.3 75 60-150 Yes Nickel 2086 .025 14 4 25.7 97.3 50 110-170 No Nickel 2088 .021 14 4 23.7 89.9 50 110-170 No Tin 2090 .007 8 1.2 23.4 88.5 50 60-120 Yes Tin 2092 .007 8 1.0 23.4 88.6 50 60-120 Yes Zinc 2100 ,011 8 2 47.1 178.1 50 60-120 Yes Zinc 2101 .011 13 4 35.3 133.6 50 60-120 Zinc 2102 Yes .011 13 4 37.6 142.5 Zinc 50 60-120 Yes 2103 .011 9 2.5 37.6 142.5 50 60- s Yes Gallium 3011 .015 1 23. 50 72 max. Yes Gold 3020 .006 8 1.0 9.5 35.9 50 60-120 Yes Gold 3021 .006 8 1.2 9.3 35.1 50 60-120 Yes Gold 3022 .006 8 1.0 8.5 32.3 50 60-120 Yes Gold 3023 .007 7 .25 2.8 10.5 50 60-120 Ye. Indium 3030 .009 10 3 22.5 85.3 50 60-120 Yes Palladium 3040 .017 8 2.0 12.9 49.,. 50 60-120 Yes Platinum 3052 .150 5 2.5 42.7 161.5 50 6J-120 Yes Rhenium 3060 .750 12 2.5. 152.5 577.3 50 Rhodium 60-120 e..., 3072 .030 10 3.5 44.1 Rhodium 167.1 50 60-120 Yes 3074 .030 7 2 14.7 55.7 Silver 50 60-120 Yes 3080 .005 13 2.5 18.4 69.7 --(liver 50 60-120 Yes 3081 .005 7 .8 14.5 Silver 55.0 50 72 min. Yes 3082 .005 13 2 14.5 55.0 Silver 50 60-120 Yes 3083 .005 12 2.5 14.5 55.0 50 60-120 Yes Nickel-Cobalt 4002 .030 14 4 28.9 109.2 50 110-170 No Tin- Indium 4003 .008 6 .75 24.5 92.9 50 60-120 Yes Tin-Lead-Nickel 4005 .006 10 1.2 15.6 59.2 50 60-120 Yes Cobalt-Tungsten 4007 .020 13 4 13.7 52.2 50 110-170 No Nickel-Tungsten 4008 .025 16 4 21.1 79.8 50 110-170 No Babbitt SAE 11 4009 .006 9 .5 13.2 50.0 50 60-120 Yes Babbitt-Soft 4010 .006 9 .5 13.2 50.0 50 60 -120 Yes Babbitt-Navy #2 4011 .006 9 .5 13.2 50.0 50 60-120, Yes

14-56 Chapter 14METAL BUILDUP unnecessary distractions, and your efficiency 3. The operations follow each other as will not decrease from fatigue. rapidly as possible and with the surface not being allowed to dry between operations. You should have adequate lighting so you can see that the preparation and plating is 4. The desired results are obtained in each proceeding properly. operation.

Refer totable14-11for special safety In most operations, you can tell by the precautions such as necessity for ventilation, appearance whether you have achieved the gloves, special clothing, etc. desired results. The visual tests are important and you should pay particular attention to those Have sufficient clean tap water available for given in this chapter. rinsing the part. Each operation is usually carried out within Review the setup nrocedure one last time to a certain voltage range asis shown in the ensure that everything necessary is available and followingpages onpreparirigspecificbase handy. This step is to avoid delays during plating materials. When a small tool is used on a small andinturnwillproduce afinerfinished area, a low voltage in the range is used. When a product. large tool is used on a large area, a high voltage in the range is used. The voltage used in a preparatory step, however, is not critical and can PREPARATION INSTRUCTION: vary by several volts.Obtaining the desired GENERAL results as determined by the visual test is again the important part of the operation. Electroplates and tank electroplates depend The following sections discuss the various on atomic attraction of the electroplate to the types of operations carried out on various base base material for adhesion. Extremely thin, materials. invisible films of oil, grease, dirt, oxides, passive films, etc. are sufficient to prevent an atomic attraction andthereisno adhesion of an CLEANING AND DEOXIDIZING electroplate. A preparationcycleisused, therefore, just prior to plating to remove step by step all the last traces of these obstacles to A cleaning and deoxidizing operationis developing excellent adhesion. usually performed first on most base materials to remove the last traces of dirt, oil and grease.. A preparation cycle consists of a number of It also removes the light oxide films on some operations,each one performing aspecific metals.Forwardcurrent(cathodic function. The number and types of operations electrocleaning) is usually used. The cleaning and the solutions used depend on the base and deoxidizing solution, however, must be used material, not on the plating solution to be used with reverse current (anodic electrocleaning) later. Each operation should be carried out whenever hydrogencontaminationand properly to ensure maximum adhesion. The embrittlement of the base material must be operations and cycle are properly carried out avoided,suchas, inthecaseofultra when: high-strength steel. The cleaning and deoxidizing operationisperformed at8to20 volts, 1.The proper solutions are used in the depending on the base material and the size of proper sequence. the tool. Higher voltages, longer cleaning times, and development of heat in-the tool are helpful 2.The solutions are used in the proper in cleaning stubborn areas. Areas surrounding direction, i.e., forward or reverse. the area to be plated should be cleaned, since oil

14-5716 MACHINERY REPAIRMAN 3 &2

Table 14-11.-Safety Precautions for Operators

Plating Coie Ave. Special Problems Ventilation Requirements Solution pH Required For Precautions Against Skin Contact

Antimony 2000 7.3 Poisonous Metal Seldom Very Strong Bismuth 2010 10.8 Poisonous Metal Seldom Moderate Cadmium 2020 0.5 Poisonous Metal- Corrosive Solution Usually Vent Strong Cadmium 2021 9.0 Poisonous Metal Seldom Very Strong Cadmium 2022 8.8 Poisonous Metal Seldom Very Strong Cadmium 2023 11.0 Poisonous Metal Seldom Very Strong Chromium 2030 6.3 Poisonous Metal Frequently Very Strong Chromium 2031 0.5 Poisonous Metal- Corrosive Solution Usually Very Strong Cobalt 2043 1.5 Seldom Moderate Copper 2050 0.5 Corrosive Solution Seldom Very Strong Copper 2051 11.1 Seldom Moderate Copper 2052 6.4 Seldom Moderate Copper 2054 1.7 Corrosive Solution Seldom Very Strong Copper 2055 1.0 Corrosive Solution Frequently Very Strong Iron 2061 2.8 Seldom Moderate Lead 2070 8.0 Poisonous Metal Seldom Very Strong Lead 2071 8.0 Poisonous Metal Seldom Very Strong Nickel 2080 2.4 Frequently Moderate Nickel 2085 7.3 Seldom Moderate Nickel 2086 3.0 Seldom Moderate Nickel 2088 3.0 Frequently Moderate Tin 2090 7.2 Seldom Moderate Tin 7.3 Seldom Moderate Zinc 2100 7.7 Poisonous Metal Seldom Very Strong Linc 2101 5.8 Poisonous Metal Seldom Very Strong Zinc 2102 4.9 Poisonous Metal Seldom Very Strong Zinc 2103 2.7 Poisonous Metal Seldom Very Strong Gallium 3011 11.0 Seldom Very Strong Gold 3020 9.9 Contains Cyanide- Cyanide In Fumes Usually Very Strong Gold 3021 7.5 Contains Cyanide- Cyanide In_fumes_ Usually Very Strong Gold 3022 5.1 Contains Cyanide- Cyanide In Fumes Usually Very Strong Gold 3023 9.7 Contains Cyanide- Cyanide In Fumes Usually Very Strong Indium 3030 9.3 Seldom Moderate Palladium 3040 8.3 Seldom Moderate Platinum 3052 0.5 Corrosive Solution Seldom Ver. Strong Rhenium 3060 1.0 Seldom Very Strong Rhodium 3072 .6 Corrosive Solution Seldom Very Strong Rhodium 3074 1.1 Corrosive Solution Seldom Very Strong Silver 3080 10.6 Contains Cyanide Seldom Very Strong Silver 3081 10.3 Contains Cyanide Seldom Very Strong 'Silver 3082 9.6 Contains Cyanide- Cyanide In Fumes Usually Very Strong Silver 3083 116 Contains Cyanide Frequently Very Strong Nickel-Cobalt 4002 2.5 Frequently Moderate Tin-Indium 4003 8.7 Seldom Moderate Tin -Lead- Nickel 4005 7.3 Poisonous Mete Seldom Vary Strong Cobalt-Tungsten 4007 2.0 Frequently Moderate Nickel-Tungsten 4008 2.5 Frequently Moderate Babbitt. SAE 11 4009 7.5 Poisonous Metc Seldom Very Strong Babbitt-Soft 4010 7.5 Poisonous Metal Seldom Very Strong Babbitt-Navy #2 4011 7.5 Poisonous Metal Seldom Very Strong

14-58 Chapter 14METAL BUILDUP and grease travel on the surface of water. A Cleanliness is of extreme importance in the thorough water rinse should follow. If water activating operation since it is the last operation "breaks" onthesurface,thecleaning and before. plating. Contamination of the solution deoxidizingtimewastooshortandthe from any source must be avoided since this step operation should be repeated. is in the forward direction and contaminants may be plated out as a nonadherent film. ETCHING With the exception of chromium, there are no visual keys as to whether the operation has An etchingoperationusinganetching been conducted properly. The passive film is solution and reverse current usually follows the invisible and on most materials such as nickel cleaninganddeoxidizingoperation.The and stainless steel no change can be detected operationelectrochemicallyremovesoxides, whenitis removed. Any change on these corrosionproductsandsmearedand materials may indicate contamination from the contaminatedsurface material,all of which activating solution, anode, or plating tool. The impair adhesion. When the unwanted surface operation, therefore, must be carried out on a materialis removed, a uniform, dull, grainy time basis with about 3 seconds spent on each appearance develops and the etching operation is part of the total area. With an activating tool discontinued. Normally, 0.000050 to 0.0002 coveringalltheareatobeplated spend, inch of material is removed and this requires therefore, about 3 seconds in the operation. 0.006 to 0.026 amp-hr per square inch of area. With a tool covering 1 /5 of the area, conduct the operation for 15 seconds, spending an equal DESMUTTING amount of time on all parts of the area. PLATING The etching operation on some materials results in the formation of a loose layer of The final preparatory operation should be insoluble material on the surface. An example of followedasquicklyaspossiblewiththe this is carbon films on the surface after etching subsequent plating operation whether itis a carbon steels. These layers can interfere with the preplate or the final desired plating. This is of development of maximum adhesion. These films particular in1;.; rl ance whenanactivating are removedby__ an_appropriate desmutting operation has D.;,:n the last step. THE PART operation. The operation is completed when the SHOULD NOT BE ALLOWED TO DRY surface is uniform in appearance and will not BETWEEN THE ACTIVATING AND PLATING become any lighter in color. OPERATIONS.

ACTIVATING VERIFYING IDENTITY OF BASE MATERIAL An activating operation is used on some base materials, such as chromium, nickel, stainless Obtaining good adhesion of a deposit begins steel,etc. to remove a "passive" film which with proper identification of the surface being quickly forms on these materials. A cleaning and plated. Frequently, the operator is misinformed deoxidizing operation on these materials does as to the identity of the base material and is not notremovethepassivefilm.An etching informed that a coating is present. This, of operation on these removes material from the course, can lead to adhesion problems. An alert surface, but simultaneously forms the passive operator, by carefully watching theetching film. Passive films prevent maximum adhesion. operation,however,cantiequentlydetect An activating operation is, therefore, conducted incorrect identification-,o-thepresence of

on these materials just prior to plating, using- coatings. The folio 7' may be helpful in this forward current and an appropriate solution. matter. (Also refer to tz ble 14-3.)

14-59 MACHINERY REPAIRMAN 3 & 2

Result of No. 2 or No. 4 Etch Reverse Operation Surface rusts Appearance of Color of Solu- after etching Material Etched Surface tion in Cover when kept wet Magnetic

Low Carbon Light Gray No Color Yes Yes Steel

Medium or Medium Gray Black smut Yes Yes High Carbon to Black in cover Steel

300 Stainless Light Gray Yellow at first No No green later

400 Stainless Light Gray glue-green No Yes Soft

400 Stainless Black Blue-green Hard with Black smut No Yes

Monel Light Gray Pale Orange No Yes

Chromium Shiny White Yellow No No

PREPLATE INSTRUCTIONS plating the preplate on the base material, a satisfactory thickness has been applied. Since It may be necessary, in some cases, to apply new operators often do not apply a sufficient a preplate with an appropriate plating solution. thickness of preplate, they should calculate and The preplate is applied immediately after the pass the ampere-hours necessary for a thickness preparation of thesurface and isfollowed ofatleast0.000025inch.Examples for immediately by a water rinse and plating with solutions are from the Dalic Selective Plating the final desired solution. The preplate ensures Manual.Eachmanufacturerhasitsown maximum adhesion of the final deposit. The instruction manual and solution guide. basematerial and thefinaldesired plating solutiondeterminewhetherapreplateis The preplate voltages used are as follows: required and, if so, what preplate is required. r. Table 14-12liststhe preplates required fer commonly used solutions on commonly plated Code Very Small ToolVery Large Tool base materials. A Code 2080 preplate and then Code 2050 preplate, for example, are required 2080 8 12 on stainless steel before plating copper 2055. A 2050 4 6 preplate is not required for plating Code 2103 on low carbon steel. 2051 5 8 The preplatc thickness applied varies from 2085 7 10 0.000010 inch on smooth surfaces to 0.000050 3023 5 8 inch on roughsurfaces.Normally, when a uniform color change is noted as a result of 3040 5 8

14-60

,5 3 Chapter 14METAL BUILDUP

Table 14-12.Preplates for Base Materials for Various Solutions

Plating Code Aluminum Copper Iron, Steel Nickel Stainless Zinc Solution and and and Cast Iron and Steel and Aluminum Copper Nickel Zinc Alloys Base Base Base Alloys Alloys Alloys

Antimony 2000 2080 2080 2080 2051 or 2085 Bismuth 2010 2080 2080 2080 2051 of2085 Cadmium 2020 2080 2080 2080 2051 0. 2085 tidmium 2021 2080 ?080 2080 2051 or 2085 Cadmium 2022 2080 1032 2080 2080 2051 or 2085 Cadmium 2023 2080 2080 2080 2051 or 2085 Chromium 2030 2080 2020 2080 2080 2080 Chromium 2031 2080 2080 2080 2080 2080

Cobalt 2043 2080 2080 2080 2080 - 2051 Copper 2050 2080 2080 2080 2051 Copper 2051 2080 2080 2080 2080 Copper 2052 2080 2080 2080 2080 2051 Copper 2054 2080+ 2050 2080+ 2050 2080+ 2050 2080 + 2050 2051 Copper 2055 2080+ 2050 2080+ 2050 2080+ 2050 2080 42050 2051 Iron 2061 2080 2080 2080 2080 2051 Lead 2070 2080 2080 2080 2080 2051 or 2085 Lead 2071 2080 2080 2080 2080 2051 or 2085 Nickel 2080 2051 Nickel 2085 2080 2080 7080 2080 Nickel 2086 2051 Nickel 2088 2051 Tin 2090 2080 2080 2080 2080 2051 or 2085 Tin 2092 2080 2080 2080 2080 2051 or 2085 Zinc 2100 2080 2080 2080 Zinc 2101 2080 2080 Zinc 2102 2080 2080 Zinc 2103 2080 2080 Gallium 3011 2080 2080 2080 2080 2051 or 2085 Gold 3020 2080 2080 2080 2080 Gold 3021 2080 2080 2080 2080 Gold 3022 2080 2080 2080 2080 Gold 3023 2080 2080 2080 2080 Indium 3030 2080 208C 2080 2051 or 2085 Palladium 3040 2080 2080 2080 2080 2051 or 2085 Platinum 3052 2080 2080 2 '1 2080 2051 or 2085 Rhenium 3060 2080 2080 2080 2051 or 2085 Rhodium 3072 2080 2080 2080 2051 Rhodium 3074 2080 2080 2080 2051 Silver 3080 2080+ 3040* 3040 2080+ 3040* J + 3040* 2080+ 3040*2051 + 3040* Silver 3081 2080+ 3040* 3040 2080+ 3040* &A0 + 3040* 2080+ 3040*2051 + 3040* Silver 3082 2080+ 304J* 3040 2080+ 3040* 2080+ 3040* 2080+ 3040*2051 + 3040* Silver 3083 2080+ 3040* 3040 2080+ 3040* 2080+ 3040* 2080+ 3040*2051 + 3040* Nickel-Cobalt 4002 2051 Tin-Indium 4003 2080 2080 2080 2080 2051 or 2085 Tin-Lead-Nickel 4005 2080 2080 2080 2080 2051 Cobalt-Tungsten 4007 2080 2080 2080 2080 2080 2051 Nickel-Tungsten 4008 2080 2080 2080 2080 2080 2051 B_ciWAt511E 11 4009 20$0 2080 20&0 2C80 2080 2051 Babbitt-Soft 4010 2080 2080 2080 L080 2080 2051 Babbitt-Navy =2 4011 2080 2080 2080 2080 2080 2051

* Gold Code 3023 may be used in place of Palladium Code 3049

14-61 MACHINERY REPAIRMAN 3 & 2

SUMMARY OF ELECTROPLATING preparations priorto plating should prevent contamination of the area being plated. Watch, The ideal plating operation is carried out however, for a possibly overlooked source of when simultaneously (1) the quality of deposit contamination such as thetool or solution is the best possible; (2) the deposit is applied in moving over a dirty surface; correct as soon as a minimum amount of time; and (3) the deposit possible. has a uniform desired thickness. A number of steps should have been taken in initial and final preparations to ensure that the Keep the Surface Wet best possible quality deposit will be applied. with Plating Solution Some of them include use of clean anodes, uncontaminated solution, proper cover material, etc.The operator,atthe time of plating, Dryingofthesolutiononthearea however, must stillcarry out the operation being plated is obviously a significant change properly. inthecompositionofthesolution.This canaffecttheadhesionofthefollowing GUIDELINES FOR THE OPERATOR deposit. Proper setups will largely ensure that the surface will not dry during plating. However, The guidelines for the operator discussed in you should watch for signs of "overheating" of detailthroughoutthis chapter, are reviewed the part and the solution. If this occurs, supply briefly in the following sections. more solution.If dipping for solution, you should dip often enough every 5 seconds or as Keep the area being plated clean. required.

Keepthesurfacewetwithplating solution. Keep Interruptions to a Minimum Keep the number and length of plating interruptions to a minimum. Some metals, primarily nickel, cobalt, and chromium are subject to passivation which is the Prevent the solution from depleting in formation, in a short period of time, of a thin the work area. invisibleoxide film. Good bond cannot be obtained without activation. Passivation can be Maintain proper anode-to-cathode speed. preventedbyavoidingallunnecessary interruptionsoftheplatingoperation, Plate at the proper current density. minimizing the length of time of unavoidable interruptions, and ensuring that all areas being Plateatapproximatelytheproper plated are covered periodically (at least every temperaturewhenplatingtemperatureis 10 seconds) during plating. important.

The first three guidelines assure obtaining Prevent Solution from good adhesion of the deposit to itself, the last Depleting in Work Area four assure obtaining best deposit quality.

Keep the Area Depletionof solutioninthe work area Being Plated Clean (Where cover meets the part) has various effects depending on the solutio;.. With most plating Contamination of the area by oil, grease, solutions, there is a greater tendency to get dirt, etc. can result in adhesion problems and shiny, low thickness deposits. Other indications possibly poor depositquality.Careful final are a drop-off in plating current and a change in

14-62 4 L'Z') Chapter 14METAL BUILDUP

color of the solution in the cover. To prevent Chisel, Knife, and Saw Test this, provide a sufficient amount of fresh plating solution and then pump fast enough or dip often If the deposit is sufficiently thick to permit enough to get it in the work area. the use of a chisel, test the adhesion by forcing the chisel between the coating and basic metal. Maintain Proper Use a hammer to apply the force. Test thinner Anode-to-Cathode Speed coatings by substituting a knife or scalpel for the chisel and lightly tap it with a hammer. Test Ensurethatthetoolisalways moving very thin coatings by scratching through the relative to the part (fig.14-12). If you set a coating to the basic metal. After these tests, plating tool on the part then move it straight closely examine thetest areafor lifting or back and forth instead of in a rotary motion on peeling of the deposit at the base material to flat parts and move the tool in the direction of a plating interface. rotating part, in some spots momentarily you have no relative movement. Burning of the deposit can result from this. Grind and Saw Tests

Visual Control Another good test for adhesion is to grind an edge of the plated specimen with a grinding While plating, you can see what the deposit wheel with the direction of cutting from the lookslikeasitisgoingdown.Deposit basic metal to the deposit. If adhesion is poor, appearance givesvaluableinformationon the deposit is torn from the base. You can use deposit quality and overall plating efficiency. If hacksaw instead of the grinder. It is important you know the significance of variations in the to saw in such a direction that a force is applied deposit and what causes them, you can, when that tends to separate the coating from the basic necessary, make appropriate corrections such as metal. Grinding and sawing tests Pre especially by changing the voltPge, the anode-to-cathode effective on hard or brittle deposits. speed, or the rate of solution supply. You should be aware of what good and bad deposits look like, pay attention to appearance while plating, and be able to make the appropriate TROUBLESHOOTING corrections when they must be made. POOR ADHESION EVALUATING DEPOSITS Carefullyinspecttheplatedareato The qualities to look for in plating deposits determine if the deposit is coming off the base inallapplications are good adhesion, proper material, the final deposit is coming off the thicknessofcoating,and highdensityof preplate, or the final deposit is coming off itself. deposit. In corrosion protection applications Examine the back side of the material coming where nonsacrificial coatings are used, also look off. Etch tests using Code 1022 or 1024 solution for freedom from pores and surface-to-base on the area where the material came off and a metal cracks. comparison cf appearance with etched deposit and etched base material is often helpful. EVALUATING ADHESION In some cases, such as when plating on metal Some of the tests that can be used in spray, tungsten carbide, electroless nickel, etc., sampling or prequalification testing, all of which the separationisinthe base material, and, are excellent, are (1) the chisel,knife, and therefore,theDALICplatingcannotbe scratch test or the grind and saw test. faulted.

14-63 4vGs MACHINERY REPAIRMAN 3 & 2

1.COMMON CAUSES FOR DEPOSIT POOR DEPOSIT QUALITY COMING OFF BASE MATERIAL Poor depositquality includes roughness, a. Base material not correctly identified. stress-cracking, and stress-crack lifting. Common 1. Determine for certain identity of causes are as follows: base material. 2. Check to determine if surface was 1.Selected wrong solution. etched as it should have been. 2.Plating solution contaminated. 3,,Plating tool contaminated. b. Surface has a foreign coating such as 4.Used wrong cover or cover too thick or metal spray, chrome plate, etc. too thin. 5.Plating wrong. 1. Determine if plated area and other areas on workpiece etch the same. LOW THICKNESS DEPOSIT Use Code1022or1024 and reverse current. Low thickness deposit, i.e., did not achieve the desired thickness. Common causes are as c. Did not thoroughly, properly, and follows: quicklycarryoutpreparatory procedure. 1.Did not properly calculate area. d. Contaminated preparatory solutions. 2.Did not properly calculate amp-hr. 3.Considerable plating went on aluminum e. Contaminated preparatory cr preplate tape or adjacent areas. tools. 4.Overetched base material. f. Preparatory tools too small. 5.Platedwrong with"variablefactor" g. Did or did not pre-wet surface prior to solution. plating. 6.Certain solutions overused. 7.Insufficient solution supply with certain h. Selected wrong plating solution. solutions. i. Did not use recommended preplate. 8.Plated in cover. Wash and examine cover to see if this actually occurred. 2. FINAL DEPOSIT COMING OFF 9. Nonuniform distribution of plating and PREPLATE measuring in low areas.

a. Did not followquickly withfinal NONUNIFORM THICKNESS OF DEPOSIT plating solution. 1.Tool not right. b. Did or did notpre-wet surface per 2. Tool not used right. instructions. 3.Solution not distributed uniformly in cover. c. Selected wrong plating solution. 4. Tool cover thickness varied.

3. FINAL DEPOSIT COMING OFF TOOK TOO LONG TO FINISH JOB ITSELF 1.Used wrong solution. a. Burned deposit. 2.Plating tool too small. b. Plating operation interrupted too long. 3.Power pack too small. c. Solution contaminated. 4. Not plating as fast as possible with existing tool or solution.. d. Contaminated anode. 5.Did not preheat properly certain variable e. Wrong anode cover used. factor solutions.

14-64 eLj.-7 Chapter 14METAL BUILDUP

MACHINING AND GRINDING used, assurefast,efficient, and trouble free DALIC plating operations. Machining Formula 1: Formula to control thickness of The deposits softerthan 250 Brinell are metal deposited easily machined and specific recommendations are not necessary for these. Amp-Hr=FXAXT The cobalt, iron, and nickel deposits or their alloys are difficult to machine. If possible, grind ratherthan machine. Whenitisabsolutely This formula should be used to necessarytomachine, good equipment and determine the ampere-hours that techniqueisrequired.Recommendations should be passed while plating to include: obtainthedesiredthicknessof deposit on the area to be plated. 1.Use new tight machine tools. Inthis formula, F is the factor 2.Use sharp carbide bits. obtainedfromplatingsolution 3.Use plenty of coolant. bottle or table 14-5. 4. Take light cuts of approximately 0.005 A = area of surface to be plated in inch. square inches. 5.Uselowcuttingspeeds,i.e., T = thickness of deposit desired in approximately 50 ft/min. one ten-thousandths inches.

Grinding Nickel and Deposit Thickness T equals Cobalt Deposits DesiredInches

TheNortonCompany,Worcester, 0.010 100.0 Massachusetts,makes thefollowing recom- 0.002 20.0 mendations relative to grinding nickel or cobalt 0.001 10.0 deposits: 0.0005 5.0 0.000060 0.6 1.Wet grinding recommended. Use plenty 0.000008 0.08 of coolant. Note: The proper value for T to 2.WheelSilicon Carbide Vitrified. put in the above formula may, also, beobtainedbywritingthe 37060KVK Recommended. thickness desired in inches and then moving the decimal point four (4) 3.Wheel and Work SpeedsWheel 6000 places to the right. surface feet per minute. Example: 4.Depth of Cut-0.0002 inch maximum to ensure against overheating of the deposit and deposit to base metal interface. 0.001 inch thickness desired 0.001 is the same as 0.0010 FORMULAS move the decimal point four places to the right, There are a number of formulas that prove i.e., 0010. very useful with the DALIC Process. They, when T, therefore, is 10

14-65 4 MACHINERY REPAIRMAN 3 & 2

Formula 2: Formulatodeterminecurrent Thisformulais(usedfor two density purposes, i.e.,

1. In conjunction with Formula PA CD= 5 to estimate plating time. CA CD = current density in amps per 2. By itself to determine if one square inch isplatingattheright PA = plating amperage amperage. CA = contact area being made by the plating tool on the part in Formula 5: Formula to estimate plating time square inches Arap-Hrs PT (Hrs) Thisformulaallowsoneto compute thecurrent density at PA = valuefrom Formula 4 for which you are plating in a given purpose1 or average current operation. A comparison can then while plating for purpose 2 be made with values given in table 14-3 to determine if one is plating Thisformulaisusedfortwo at a low current density, a normal purposes: currentdensity,or an excessive current density etc. The operator 1. To estimate plating time in withthis information canthen setting up a job makeappropriateadjustments 2. To control thickness when while plating. no ampere-hour meteris available Formula 3: Formulato determine optimum platingtoolcontact area when Formula 6: Determining amount of solution designing special tools required

MA Liters = Q(L) X T(I) X A OCACD7 Thisformulaisused(1)in MA = maximum aperage output of estimating jobs and (2) to ensure power pack to be used thatappropriateamountsof ACD = average current density for solution are available and used in a solution to be used given job. This formula should be used when Q(L) is Solution Required Average designing special tools to develop per Inch3 in liters from table 14-10. the right size tool, neither too large or too small. T(I) = thickness of deposit desired in inches Formula 4: Formulatoestimateplating amperage to be drawn with a given A = area of surface to be plated solution and plating tool Formula 7: Formulatocheckampere-hour PA = CA X ACD meter accuracy ACD = average current density for solution Amp-Hrs = Amps X Hrs

14-66

4 tr Chapter 14METAL BUILDUP

This formula is used periodically as Placing these values in the above a maintenance procedure to ensure fcrmula that the amp-hr meter is accurate, or in cases where its accuracy is Amp-Hr = 20 X 0.05 suspect. The test is run by shorting the d.c. Amp-Hr = 1.00 output leads and running the power pack for a set time (hr) at a set amperage. Assume a test is run for The computed value (1.00) should 3 minutes at 20 amps. be close (within a small percentage) to that passed on the amp-hr meter Amps = 20 when shorting the d.c. output leads 3 and running for 3 minutes at 20 Hrs = -6-0- or 0.05 amps. CHAPTER 15

THE REPAIR DEPARTMENT AND REPAIRWORK

As a Machinery Repairman you may be tenders, the repair department on a repair ship gned to almost any type ship. Aboardmany or tender makes a direct and vital contribution ps, you will be a member of the engineering to fleet support. The operating forces of the d artment;mostMachineryRepairmen, fleet depend upon the services provided by all howver, are assigned to repair and tender type personnel of tht.. repair department. ships. On ships of this type, you will be pait of therepairdepartmentandshouldknow something about its functions, personnel, and REPAIR DEPARTMENT shops. In this chapter, you will also findsome ORGANIZATION AND PERSONNEL examples of tin type of repair work you are likely to encounter. The type of repair ship to which you will probably be assigned will be a destroyer tender Ineffect,repairships andtendersare (AD), a repair ship (AR), an internal-combustion floating bases, capable of performing a variety of engine repair ship (ARG), or a submarine tender maintenance and repair services that are beyond (AS). When you are assigned to shore duty,you the capabilities of ships they se-ve. They are will almost certainly be assigned to a billet in the rather like small-scale Navy yards, with the same Repair Department of a shore installation. Since primary mission: to provide repair facilities and theshore-basedinstallationhasthe same services to the forces afloat. essentialmissionastherepairship,the organization will be similar. The most common type of repair designated AR, provides general and spe,-.t1 When you report aboard ship, you will need repairs to all types of ships. Special types to learn the lines of authority and responsibility repair ships have been developed for specialuses; in the repair department. You will need to find for example, the ARG is designed for the repair outwhere.yourordersandassignments of internal-combustion engines. originate, exactly what is expected ofyou, and where to go for information, assistance, and Each type of tender provides services for one advice. You can start acquiring this knowledge type of ship, as indicated by the designation of by studying the following material on repair the tender. The two best known types of tenders department organization and personnel. are the destroyer tender (AD) and the submarine tender (AS). Both conventional submarines and Rep airdepartmentorganizationvaries fleet ballistic missile submarines are tended by somewhat from one ship to another, as you can the AS; however, the organization of the repair see by comparing figures 15-1 and 15-2. Figure department of an AS that tends fleet ballistic 15-1shows the organizationof therepair missile submarines differs somewhat from that department in a typical repair ship (AR); figure of an AS that tends conventional submarines. 15-2 shows the organization of therepair Since repairs and services to other ships are department in a fleet ballistic missile (FBM) the primary functions of all repair ships and submarine tender (AS).

15-1 MACHINERY REPAIRMAN 3 & 2

REPAIR OFFICER SHIP SUPERINTENDENTSI

MAINTENANCE DATA ASSISTANT REPAIR ADMINISTRATIVE COLLECTION COORDINATOR OFFICER ASSISTANT

RI DIVISION R-2 DIVISION R-3 DIVISION R-4 DIVISION R-5 DIVISION HULL REPAIR MACHINERY REPAIR ELECTRICAL REPAIR ELECTRONICS REPAIR ORDNANCE REPAIR

SHIPFITTER SHOP MACHINE SHOP ELECTRICAL REPI!R TYPEWRITER & GAGE CANVAS SHOP SHE EimETAL SHOp OUTSIDE REPAIR SHOP SHOP SHOP OPTICAL SHOP PIPE SHOP BOILER SHOP I.C. REPAIR SHOP WATCH & CLOCK SHOP PHOTO SHOP CARPENTER SHOP DIESEL SHOP ELECTRONICS SHOP ORDNANCE DIVING ENGRAVING SHOP TELETYPE SHOP FIRE CONTROL MELDING SHOP VALVE SHOP ELECTRONICS CALIBRA DRAF TING FOuNCRY TOOL ROOM TION LAB PRINTING PATTERN SHOP

63.10 Figure 15- 1. Organization of repair department in typical repair ship (AR).

In comparing the two illustrations, you will ships tended or granted availabilities. The repair notice several differences. For one thing, the officerisalsoresponsibleforaccomplishing repairdepartmentinthe AR includes an repairs and alt,rations to the ship itself (tender ordnance repair tlivision (R-5) which is not or repair ship) wnich are beyond the capacity of included in the repair department of the AS. the engineering or other departments. The repair Instead, the AS has a separate weapons repair officerisresponsibleformaintaining a department under a weapons repair officer. In well-organizedandefficientlyoperated all types of repair ships, you will probably be department, or, in other words, for ensuring that assigned to the R-2 division. The machine shop subordinates perform as required. He issues and is normally within the R-2 division organization. enforces repair department orders which govern department procedures. Like other department Thedutiesofpersonnelintherepair heads, he is also responsible for enforcing orders department vary somewhat according to the of higher authority. He must know the current type of ship. However, the following descriptiou workload and capacity of his crew and facilities, of personnel functions will give you a general and keep the staff maintenance representative idea of the way thingsarein most repair informed of the current status in order that the departments. latter officer may properly schedule and assign ships. He is responsible for the review of work requestsreceivedviathestaff maintenance REPAIR OFFICER representative from the ships assigned for repair and for acceptance or rejection of the individual jobsaccordingtothecapacityofhis In a repair ship or tender, the repair officer department. He is responsible for the review and is head of the repair department. As head of the acceptance of any work lists or work requests repairddpartment,therepairofficer is which develop after an availability period has responsible under the commanding officer for started. He is also responsible for operating the accomplishing repairs and alterationsto the department within the allotment granted and for l5-i Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

LRE; AIR OFFICER _1 ASS AT REPAIR OFFICER

MAINTENANCE DATA COLLECTION COORDINATOR

DEPARTMENT TRAINING OFFICER ADMINISTRATIVE ASSISTANT

[PRODUCTION ENGINEERING RADIOLOGICAL CONTROL ASSISTANT OFFICER I

REPAIR SERVICES OFFICER REPAIR TECHNICAL OFFICER R-S DIVISION

RADIOLOGICAL . R6 DIVISION R-7 DIVISION PHOTO SHOP PLANNING OIL & WATER TEST LABORATORY NOISE, VIBRATION, AND REPAIR OFFICE SOUND ANALYSIS PRINT SHOP ELECTRONICS DRAFTING STANDARDS TECHNICAL LIBRARY QUALITY CONTROL DIVING GANG

SHIP SUPERINTENDENTS REPAIR ASSISTANT

I HULL REPAIR MACHINERY REPAIR ELECTRICAL REPAIR ELECTRONICS REPAIR OFFICER OFFICER OFFICER OFFICER

12-, DIVISION R-2 DIVISION 12-3 DIVISION 124 DIVISION

SHIeFITTER SHOP MACHINE SHOP ELECTRICAL SHOP SHOP 67 PIPE SHOP OPTICAL SHOP RUBBER & PLASTIC SHOP SHOP 57 SHEETMETAL SHOP INSTRUMENT SHOP GYRO REPAIR SHOP SHOP 61 WELDING SHOP OUTSIDE MACHINE SHOP CARPFNTER SHOP PATTERN SHOP CANVAS SHOP

63.10A Figure 15- 2. Organization of repair department in fleet ballistic missile submarinetender (AS). the initiation of requests for further funds, if advancement in rate, assignment to divisions, required..Hemustensuretheaccuracy, and leave. To acquire a thorough knowledge of correctness,andpromptnessof allcor- conditions and ensure adequate standards, he respondence,includingmessages, prepared mustmakefrequentinspectionsofthe for the commanding officer's signature. The department and require the division officers to repair officer is charged with the review of all make corrections as necessary. personnel matters arising inall the divisions Specific duties of the repair officer vary withinthedepartmentsuchastraining, somewhat, depending upon the type of repair

15-3 4 MACHINERY REPAIRMAN 3 & 2 ship or tender. In general, however, a .ummary Specific duties of the assistant repair officer oftherepairofficer'sdutiesincludethe may vary somewhat, depending upon the type following: of repair ship or tender. In general, however, the duties of the assistant repair officer include the following: Plan,prepare,and execute schedules covering alterations and repair work assigned to the repair department. Assign personnel to divisions, schools, shore patrol, and beach guard. EstablishandoperatethePlanned Maintenance System of the 3-M System. Have a basic knowledge of applicable courses, schools, and rating programs necessary capabilities,work Coordinaterepair tofurther education of personnel and their assignments, and available personnel to ensue advancement in rateforthe benefit of the maximum use of manpower. personnel, the ship, and the Navy.

Supervise and inspect repairs and service to ensure timely and satisfactory completion of Maintain the office stores and accounts. work; provide controls for quality control. Assist the repair officer in all matters Preparerecords,reports,forms, and pertaining to general office routine, current orders in connection with repair functions and availabilities of ships assigned to the repair ship duties. or tender, and liaison between the repair office and the ship alongside and in shipyards. Ensureproperoperationofall equipment and material assigned to the repair department. Review all work requests on receipt.

Ensurestrictcompliance with safety Assign work and priority rating to the precautions and security measures. division and shops. Report progress of major repairs and alterations to the commanding officer; keep the Maintainliaisonwiththesupply executive officer informed; report promptly any department for materials on order or to be inability to meet scheduled completion dates. ordered for the work requested.

ASSISTANT REPAIR OFFICER Procurethenecessaryblueprints, sketches, or samples for the shops.

In the absence of the repair officer, the Schedule the services of tugs, cranes, and assistantrepairofficerischarged with the technical services, as available, for successful responsibilities of therepairofficer. As the completion of an availability. assistantrepairofficer, heisthe personnel administrator for the repair department. Under his cognizance are the assistant of personnel, the Survey the report from the shop to administrative control of the repair office, and ascertain the successful completion of all work the department control of training. during the allotted time.

15-4 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

Analyzeman-hour shopreportsto also learn about the work of these ratings by determine aneven balance of work versus observing how the work is handled in the repair personnel assigned. Regulate the coordination department. In handling repair work, it is often between the repair office and the shops toward necessary for two or more shops (and two or thefullproductivecapacityof therepair moreratings)tocooperatetocomplete facilities. corrective maintenance actions. In addition to the assistant repair officer, there are usually several other officers who assist the repair officer in the performance of repair REPAIR DEPARTMENT SHOPS department functions. These may include a productionengineeringassistant,arepair assistant,aradiologicalcontrolofficer,a Each shopintherepair department is departmenttrainingofficer,andan assigned to one of the divisions. As a Machinery administrative assistant. Repairman you will be concerned primarily with the machine shop. However, you will find itvery useful to learn as much as you can about the DIVISION OFFICERS other shops. After you have gotten acquainted with personnel in your own shop and have learned to find your way around your own Each division within the repair department is working spaces, make at: effort to find out under a division officer. The division officer may something about the other shops in the division be a commissioned officer, a warrant officer, or and department. Find out where each shop is a chief petty officer. The duties of the division located, what kind of work is done in each shop, officer vary, of course, according to the nature andwhatadministrativeproceduresare of the work done in the division. necessary when one shop must call on the services of another for assistance in completing corrective maintenance actions. ENLISTED PERSONNEL

MACHINE SHOP LAYOUTS As a Machinery Repairman assigned to the repair department of a repair shop or tender, you will work with people in a number of other Shoplayoutan d arrangementvary ratings. It will be very much to your advantage somewhat from one ship to another depending to learn who these people are and what kind of upon space available, the nature and amount of work they do. Ratings that are often assigned to equipment installed, and the services that must the repair department include (but are not beprovidedbytheship.Thefollowing limited to) Opticalmen, Electronics Technicians, discussion is intended to give a general picture of Radiomen, Fire Control Technicians, Gunner's a shop layout in AR, AS, and AD type ships. Mates,Draftsmen,Lithographers,Hull Figure 15-3 shows the layout of a Navy machine MaintenanceTechnicians,Patternmakers, shop in a new submarine tender. Molders, Machinist's Mates, Boiler Technicians, Enginemen, Gas Turbine Systems Technicians, Most machine shops are broken down into Electrician's Mates, and IC Electricians. sections as you can see in figure 15-3. These sections are lathe, milling, engraving, grinding, You can get some idea of the work done by and heavy. Also included in the layout is a people of these ratings by looking through the toolroom and shop office. The toolroom should Manualof NavyEnlistedManpower and be as centrally located as possible and be of PersonnelClassificationsandOccupational adequate size to store all the tools needed for Standards,NAVPERS 18068 (revised). You can the work required of the shop.

15-5

4 ' ' MACHINERY REPAIRMAN 3 & 2

ISTORAGE BENCH

TABLE COFFEE 3-0 SAW MESS AND PANTOGRAPH WASH AREA

VERT. ENGRAVING-SECTION PAINT LAY-OUT MILL-SECTION BENCH SPINDLE BENCH P1NTOGRAP STORAGE TABLE MILL LADDER CUT-DFF SAW BAND SAW

VERTICAL HORIZONTAL SHAPER SHAPER DRILL PRESS STOCK DRILL RACK PRESS FOAM SMALL LATHE TRUNK STATION VERTICAL PLANER L ATHE TJRRET HYO. PRESS] LATHE

DRILL ABRASIVE GRIND. L ATHE L ATHE CUT-OFF PRESS

BALANCING TRUNK MACHINE L L A A A HEAVY- BENCH A A E LARGE GAP L ATHE- T T T SECTION LATHE LATHE H BENCH SECTION H H H H C ULT dASON,C CLEANER AFT

FORWARD SHOP OFFICE TOOL ROOM

LADDER

SURFACE TOOL 8 DRILL GRIND SECTION BENCH STORAGE GRINDER CUTTER GRINDER AREA

HONE TOOL MAKERS (HEAT TREATMENT' 'CYLINDRICAL GRINDER MACH LATHE OVEN

28.313 Figure 15-3.Machine shop layout (new submarine tender).

The positioning of the machines is of great that the monorail system covers all machines importance. In figure 15-4, you can see that the and work benches. lathesarepositionedheadstock endto footstock end. This way the operators won't interfere with one another, and the chips from OTHER REPAIR SHOPS one machine will not fly in the direction of the nextoperator. Goodlightingisof prime importance also. In figure 15-4 you can see good As previouslystated, you should get to overhead lighting as well as work lights on the knowtheothershopswithintherepair machines.Theproblemofonemachine department. Machining is only a small portion of interfering with another is taken care of by a Machinery Repairman's work. You can expect angular placement as illustrated in figure 15-5. A to work with every shop within the Repair good monorail system is another important asset Department. An example of this might be hatch to the machine shop. You can see in figure 15-5 dogs. The pattern shop makes the pattern, the

15-6 110 4I) () Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

,11111 LOSS. $ 6off

28.314 Figure 15-4.Machine shop lathe secdon.

molders cast them in the foundry, the machine and gears must be made in the machine shop shop machines them, and possibly the outside (see fig. 15-6). repair shop installs them. You can see from this example that a smooth flow of work demands A major portion of the repair work done in close cooperation between many shops. shipboard machine shops involves machining worn or dPmaged parts so that they can be piacc.d back in service. For example, the sealing REPAIR WORK surfaces of valves and pumps must be machined if leaks occur; broken studs must be removed, and bent or damaged shafts must be repaired. Replacementparts for most equipment are This repair work is usually more difficult than usuallyavailablethroughthe Navy supply manufacturing workbecauseofalignment system. But occasionally, parts such as shafts problems in the machining operation. MACHINERY REPAIRMAN 3 & 2

28.315 Figure 15.5. Machine shop milling section.

Many of the repair jobs that you will be the drawing or sample until you are familiar assigned to do will require you to make certain with the details and ensure that you have all mathematical calculations such as finding the pertinent information. areas of circles, rectangles, and triangles and Decide which machines are required for calculating linear dimensions. You may also have making the part and calculateall necessary to find the volume of cylinders and cubes. dimensionsfromthe informaticn provided. Information such as this may be obtained by Choose the most logical sequence of machining usingtheformulasfoundinthevarious operations so that the part is machined in a machinist's handbooks andinMathematics, minimum number of setups. Volume 1,NAVPERS 10069-C. When you are making a replacement part, GEARS the leading petty officer of the shop will usually give you a working drawing of the part or a When manufacturing gears, you may need to sample part similar to the one required. Study calculate simple gear trains or gear trains using

15-8 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

28.361 Figure 15-7.Cutting specially shaped grooves.

28.360 Figure 15-6.Part made in a machine shop. paranthesesarestandardgear nomenclature symbols used and taught at MR Schools): compound gearing. Information on this subject OUTSIDE CIRCLE (OC): The circle formed may be found inBasic Machines,NAVPERS by the tops of the gear teeth. 10624-A. OUTSIDE DIAMETER (OD): The diameter A gear is made by cutting a series of equally to turn the blank to; the overall diameter of the spaced, speciallyshapedgroovesonthe gear. periphery of a wheel (see fig.15-7). A rack is made by cutting similar grooves in a straight surface. The grooves and teeth of a spur gear are PITCH CIRCLE (PC): (a) Contact point of straight and parallel to the axis of the wheel. mating gears, basis of all tooth dimensions. (b) Imaginary circle one addendum distance down To calculate the dimensions of a spur gear, the tooth. you must know the terms used to designate the parts of the gear. In addition, you must know PITCH DIAMETER (PD): (a) The diameter the formulas for finding the dimensions of the of the pitch circle. (b) In parallel shaft gears, the parts of a spur gear. To cut the gear you must pitch diameter can be determined directly from know what cutter to use and how to index the the center to center distance and the number of blank so that the teeth are equally spaced and teeth. have the correct profile. In chapter 11 of this manual, you learned how to index. ROOT CIRCLE (RC): The circle formed by the bottoms of the gear teeth. Spur Gear Terminology ROOT DIAMETER (RD): The distance The following terms (see fig. 15-8) are used from one side of the root circle to the opposite to describe gears anc' gear teeth (symbols in side passing through the center of the gear.

15-9

4 MACHINERY REPAIRMAN 3 & 2

ADDENDUM CIRCLE PITCH CIRCLE LINE OF ACTION WHOLE DEPTH BASE CIRCLE PRESSURE WORKING DEPTH ANGLE

ADDENDUM

DEDENDUM

FACE CLEARANCE FLANK

RIM

HUB

CT= CIRCULAR THICKNESS CP= CIRCULAR PITCH tc = CHORDAL THICKNESS ac 7. CHORDAL ADDENDUM ROOT CIRCLE

28.259.1 Figure 15.8. Gear terminology.

ADDENDUM (ADD): The height of that DEDENDUM (DED): (a) The depth of the part of the tooth extending outside the pitch tooth inside of the pitch circle. (b) The radial circle. distance between the root circle and the pitch circle. CIRCULAR PITCH (CP): The distance from a point on one tooth to a corresponding point WHOLE DEPTH (WD): The radial depth onthenexttooth measured on the pitch between the circle that bounds dr top of the circle. gear teeth and that which bounds the bottom. WORKING DEPTH (WKD): (a) The whole CIRCULAR THICKNESS (CT): (a) One-half depth minus the clearance. (b) The depth of of the circu,dr pitch. (b) The length of the arc engagement of two mating gears, the sum of between the two sides of a gear tooth, on the their addendums. pitch circle. CHORDAL THICKNESS(tc):(a)The CLEARANCE (CL): The space between the thickness of the tooth measured at the pitch top of the tooth of one gear, and the bottom of circle. (b) The section of the tooth that is the tooth of its mating gear. measured to see if the gear is cut correctly.

15-10 GO Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

CHORDAL ADDENDUM (a,): The distance Diametral Pitch System from the top of a gear tooth to a chord subtending (to extend under) the intersections The diametral pitch system was devised to of the tooth thickness arc and the sides of the simplify gear calculations and measurements. It tooth(usedforsettinggeartoothvernier is based on the diameter of the pitch circle, calipers for measuring tooth thickness). rather than on the circumference. Since the circumference of a circle is 3.1416 times its DIAMETRAL PITCH (DP): (a) The most diameter, this constant must always be taken important calculation, it regulates the tooth size. into consideration in calculating measurements (b) The ratio of the number of inches of the basedonthepitch circumference.Inthe pitch diameter. (c) The number of teeth that diametral pitch system, however, the constant is will go into each inch of the pitch diameter inasense"builtinto" thesystem,thus evenly. simplifying computation. NUMBER OF TEETH (NT): The actual When using this system, there is no need to number of teeth of the gear. calculate circular pitch. Indexing devices based on the diametral pitch system will accurately BACKLASH (B): The difference between spacetheteeth,andtheformedcutter the tooth thickness and the tooth space of associated with the indexing device will form the engaged gear teeth at the pitch circle. teethwithinthenecessaryaccuracy.All calculations, such as center distance between The symbols used by the American Gear gears and working depth of teeth, are simplified Manufacturers Association to describe gears and by the diametral pitch system. gear teeth are different from those used by the Navy. The following listwill familiarize you Many formulas are used in calculating the with these symbols. dimensions of gears and the gear teeth. Only the formulas needed in this discussion are given Spur Gear Terms Machinery American Gear here; a more complete list of formulas for Repairman Manufacturers calculating the dimensions of gears is provided in School Association AppendixIIof this manual. Appendix III Abbreviations Abbreviations contains explanations of how you determine the formulas to calculate the dimensions of gear Pitch Circle PC teeth. Pitch Diameter PD D Center to Center CC C Usually the outside diameter (OD) of a gear Distance and the number of teeth (NT) are available from Addendum ADD a a blueprint or a sample gear. Using these two Dedendum DED d known factors, you can calculate the necessary Working Depth WKD hk data. aearance CL c For example, to make a gear 3.250 inches in Whole Depth WD ht diameter that has 24 teeth: Root Circle RC * Do Outside Diameter OD 1.Find the pitch diameter (PD) using the Circular Thickness CT tc formula: Circular Pitch CP P Diametral Pitch DP P Number of Teeth NT N PD(NT) OD Root Diameter RD DR NT + 2 Chordal Thickness tc * Chordal Addendum ac * PD =24 x 3.250783.000 inches * None 24 + 2 26 MACHINERY REPAIRMAN 3 & 2

2.Find the diametral pitch (DP) using the (on-board a repair ship) run from 1 to 48 formula: diametral pitch and 8 cutters to each pitch. To check the dimensional accuracy of gear NT DP = teeth, use a gear tooth vernier caliper (see fig. PD 15-9). The vertical scaleisadjusted to the CHORDAL ADDENDUM (ac)andthe 34 horizontal is DP = =8 scale usedforfindingthe 3 CHORDAL THICKNESS (tc). Before calculating the chordal addendum, you must determine the 3.Find the whole depth of tooth (WD) by arc tooth thickness (t) and addendum (a). the formula: The formula for the addendum is

WD 2'157 ADD = PD DP NT Using values from the preceding example, 2 157 WD ='8 0.2696 inch 3 000 ADDn 0.125 24

You can select the cutter for machining the The formula for circular thickness is gear teeth as soon as you have computed the diametral pitch. Formed gear cutters are made 1.5708 CT with eight different forms (numbered from 1 to DP 8) for each diametral pitch, depending upon the number of teeth for which the cutter is to be used. The following chart indicates the ranges of Using values from the example, teeth for various cutters. 1'58 708 CT = 0.1964 inch Number of cutter Range of teeth

1 135 to a rack 2 55 to 134 3 35 to 54 4 26 to 34 5 21 to 25 VORTICAL SCALE 6 17 to 20 PV 14 to 16 7 iiift'ft 8 12 to 13

rV HORIZONTAL SCALE If you need a cutter for a gear that has 24 teeth, use a number 5 cutter inasmuch as a number 5 cutter will cut all gears containing GEAR TOOTH from 21 to 25 teeth. Most cutters are stamped, showing the number of the cutter, the diametral pitch, the range for the number of cutter, and 28.280 the depth. The involute gear cutters usually Figure 15-9.-Measuring gear teeth with a vernier caliper.

15-12 e- t)LI ;2 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

The formula used for finding the chordal Machining the Gear addendum is The procedures for making a gear of the ac = ADD +(Ct)2 dimensions given in the preceding example are as 4(PD) follows:

=0.125 +(0.1964)2 1. Select and cut a piece of stock to make 4X3 the blank. Allowatleast1/8 inch on the diameter and thickness of the blank for cleanup 00386 = 0.125 = 0.128 inch cuts. 12 2. Check the stock in a chuck on a lathe, The formula for the chordal tooth thickness and at the center of the blank, face an area is slightly larger than the diameter of the hole required. 3. Drill and bore to required size (within t, = PDsin( X) tolerance). 4. Remove the blank from the lathe and From the example, press the blank on a mandrel. 5. Setthe mandrel and gear blank up tc = 3 x sin(V01 between centers on the lathe and machine to proper dimensions. = 3 x sin 3°45" 6. Remove the gear blank and mandrel from the lathe and set up between center of the = 3 x 0.0654 indexhead andfootstockonthemilling machine. Dial within tolerance. = 0.1962 inch 7. Select a number 5 involute gear cutter (8-pitch) and mount and center as described in chapter 11 of this manual. (No:Mathematics, VolumeII, NavPers 8. Set the index headfel.indexing 24 10071-B and variousmachinist's handbooks divisions. contain information on trigonometric functions.) 9. Start the milling machine spindle and move the table up until the cutter just touches Now set the vertical scale of the gear tooth the gear blank. Set the micrometer collar on the verifier caliper to 0.128 inch. Adjust the caliper vertical feed handwheel to zero, then feed the so that the jaws touch each side of the tooth as table up toward the cutter slightly less than the shown in figure15-9. If the reading on the whole depth of tooth. horizontal scale is 0.1962 inch, the tooth has 10. Cutonetoothgroove,indexthe correct dimensions; if the dimension is greater, workpiece for one division and take another cut. the tooth groove is too shallow; if the reading is Check the tooth dimensions with a vernier gear less, the tooth groove is too deep. tooth caliper as described previously. Make the required adjustments to provide an accurately Sometimesyoucannotdeterminethe "sized" tooth. outside, diameter of a gear or the number of 11. Continue indexing and cutting until the teeth from available information. However, if a teeth are cut around the circumference of the gear dimension and a tooth dimension can be workpiece. found, these dimensions can be keyed into one or more of the formulas in Appendix II of When machining a rack, space the teeth by thistrainingcoursesothattherequired moving the worktable an amount equal to the dimensions can be calculated. circular pitch of the gear for each tooth cut.

157.13 U3 MACHINERY REPAIRMAN 3 & 2

Calculate circular pitch by dividing 3.1416 by the manufacturer's technical manual for the the diametral pitch or machinery component for which the shaft is required. The encircled numbers indicatea 3.1416 sequenceofoperationsfor CP machining the DP various surfaces of that shaft. Select and cut a piece of round stock which Calculationsforcorrectedaddendumand is at least 1/16 inch larger in diameter and 1/8 chordal pitch need not be made for checking inch longer than the shaft. Face and centerdrill rack teeth dimensions because on racks the each end of the stock. In facing, ensure that the addendum is a straight line dimension and the workpiece is faced to the correct length for the tooth thickness is one-half the linear pitch. shaft, which in this example is 20 11/16 inches. Most of the linear dimensions in figure 15-10 are given in the form of mixed numbers or proper SHAFTS fractions which indicate that rule measurement of these dimensions will be sufficiently accurate. In manufacturing a new shaft, you must take all The repair or manufacture of components linear dimensions from the same reference point such as pump or rotor shafts is an important to ensure the correct lengths. However, the partofmachineshopwork.Information linear position of the grooves at numbers 11 and provided here will help you to see the proper 12 are in the form of decimal fractions and method of manufacturing a new shaft and also require greater accuracy than is available by rule theproper methodof repairing a bent or measurement. damaged shaft. The shaft shown in figure 15-10 may be machined in two lathe setups and two mill setups.Plainturning required on surfaces 1 Manufacturing a New Shaft through 6 (see encircled numbers infigure 15-10) is performed in the first lathe setup; surfaces 7 through 12 are machined in the second Figure 15-10 illustrates a shaft that might be lathe setup. Keyways 13 and 14 are machined in made in the machine shop. The information the first milling setup and then the cuaer is given in the illustration is normally available in changed for machining the Woodruff keyway

@ 8 s/e t.C) (1) .4, e ® cas,v2% .,(.1 04' If' O`1 1. A C "' 40" p 0° 047°01: °k5141'" 9/ isv 1, 1, g41,41° "/ .1$ 1-Ck rlx 0,8 T 05)

f-9' sz i 149 - 1.119

2 h 5-1 sir ? zori

28.281 Figure 15.10. Steps in making a shaft.

15-14 r- Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

(15).Formachiningtheshaft,takethe 8. Remove the shaft from the lathe and following steps: mount inthe milling machine and mill the keyways to the required dimensions. 1. Turn the workpiece to a 2 3/16 ini..h diameter. Check the diameter for taper and Because relatively small depths of cuts are make corrections as necessary. taken, each surface of this shaft is finished in 2.Set hermaphrodite calipers to 11 3/32 one pass. Check the dead center frequently to inches and lay out the shoulder between the see that it does not overheat and to prevent the 2 3/16 inch diameter and 2.050 inch diameter. workpiece from becoming loose on the center. Usingthecrossfeedhandwheelwiththe Use a center rest as necessary, for supporting the micrometer collar set on zero, feed the tool in work. 0.068 inch (which is one-half of the difference you get by subtracting 2.050 from 2 3/16). Repairing Shafts Make a short length of cut at the end of the shaftandmeasurethediameterwith Bent shafts 1 1/4 inches and less in diameter micrometers. Adjust the crossfeed handwheel as which are used for low-speed operations can be straightened so that they have less than 0.003 - +.0 required to provide the 2.050.0000diameter to0.004-inch runout. Before attempting to straighten a shaft, however, always ensure that and complete the cut to the Id/outline. the leading petty officer of the shop is informed 3. Useproceduressimilartothose of the operation. To straighten a shaft take the described in step 2 for machining surfaces 3 following steps: through 6. Be :xtremely careful to accurately measure the kilometer of the beginning of each 1.Mount the shaft between centers in a cut to ensure that you hold the dimensions lathe. If the shaftis too long for mounting within the range provided in the illustrations. between centers, mount it in a 4-jaw chuck and 4. Turn the workpiece end-for-end and center rest. machine surfaces 7, 8, and 9 as described in step 2.Clamp a dial.indicator on the compound 2. ' rest and locate the area of the bend and measure 5.'Seta3/16-inchparting toolinthe how much theshaftisbent (runout). To toolholder and (by rule measurement) position determine the area of the bend, run the dial the tool for making groove 10 and make the indicator along the shaft longitudinally. The groove. greatest variation of the pointer from zero 6.Set the compound rest parallel to the indicates the bend area. With the dial indicator axis of the workpiece for laying out grooves 11 set at this point, rotate the shaft and note the and12.Place . a sharp pointed toolin the amount of fluctuation of the pointer. This toolholder and align the point of the tool with fluctuation is the amount of runout. Mark the the shoulder between surfaces 7 and 8. Then use longitudinal position of the bend and the high the compound rest to move the tool 1.152 side of the bend with chalk or a grease pencil. incheslongitudinallyasindicatedbythe 3. Remove the shaft from the lathe and micrometer collar on the compound feed screw. place it on a hydraulic press. Place a V-block on Feed thetool wardthe work with the each side of the bend area and turn the shaft so crossfeed until a lineis scribed on the that the high side is up. Move the press ram s..rfaceoftheworkpiece. Now swivelthe downward until it touches the shaft. Set up a compound to the angle required for cutting the dial indicator so that the contact point contacts chamfer and cut the chamfer. (Calculate the the high side of the shaft as near to the ram as angular depth from the given dimensions.) Then possible. using a parting tool between 0.053 and 0.058 4.Carefully apply pressure on the shaft inch wide, make the groove. with the ram. Watch the pointer of the dial 7. With a fine cut file, remove all sharp indicator to determine how much the shaft is edges from shoulders and grooves. "sprung" in the direction opposite the bend.

15.15 5U5 MACHINERY REPAIRMAN 3 & 2

When the indicator reading is 0.002 or 0.003 portion of the shaft plus the depth of the hole inch greater r'an the amount of ninout. release drilledintheshaft.Thisprovidesample the un. pressure, machinirg allowance. 5.Set up the shaft between centers and 9. Machine one end a the stub to a press check again as explained in step 1. Repeat steps fit diameter of the hole in the shaft. The length 2, 3, and 4 until the runout is decreased to the of this portion should be slightly less than the required limits. depth of the hole in the shaft. (A screw fit between the shaft and stub can be used instead If little or no change in runout results from of the press fit.) thefirststraighteningprocedure,theshaft 10. Chamfer the shoulder of the machined should be sprung farther in the second operation end of the stub the same amount as the shaft is to overcome the elasticity of the shaft so that it chamfered. bends in the required direction. However, it is 11. Press (or screw for a threaded fitting) the better to use several steps for straightening the stub into the shaft and have the chamfered joint shaft a few thousandths of an inch at a time welded and stress relieved. than to attempt to straighten the shaft in one or 12. Mount the shaft with welded stub back two steps with the possibility of bending the in the lathe and machine the stub to the original shaft too far in the direction opposite to that of shaft dimensiors provided by the drawing or the original bend. blueprint. Damaged ends of shafts can be repaired by removing the bad section and replacing it with a VALVES new stub end. Check with the type commander to ensure that stubbing of shafts is allowed. Inrepairingvalves, you must havea Take the following steps when stubbing a knowledge of the materials from which they are shaft: made. Each materialhasitslimitations of pressureandtemperature;therefore,the 1. If a blueprint is not available, make a materials used in each type of valve depend drawing of the shaft showing all dimensions. upon, the temperatures and pressures of the 2. Machine a piece of scrap stock (spud) in fluids which they control. the lathe to the diameter of the shaft at the Valves are usually made of bronze, brass, point wherethecenterrestwillbe used. ..ast or malleable iron, or steel. Steel valves are Careftilly aligltheti center rest on this spud. either cast or forged and are made of either plain 3. Mount the undamaged :,nd of the shaft steel or alloy steej. Alloy steel valves are used in in a 4-jaw chuck and "zero in" the shaft near the high-pressure,high-temperaturesystems;the jaws of the chuck. Use sofa jaws or aluminum disks and seats of these valves are usually shims to prevent damage to the shaft surface. surfaced with a chromium-cobalt alloy known as 4. Position the previously set center rest Stellite. This material is extremely hard. under the shaft so that the center rest is between Brass and bronze valves are never used for the chuck and the damaged ens: of the shaft. temperatures exceeding 550°F. Steel valves are 5. Cut off the damaged portion of the used for all services above 550°F and for lower shaft. temperatures where conditions, either internal 6. Face, centerdrill, and drill the end of the or external, such as high-pressure, vibrations, or shaft. The diameter of the hole should be about shock, may be too severe for brass or iron. 5/8 of the diameter of the shaft; the depth of Bronze valves are used almost exclusively in the hole should be at least 1 1/2 times the hole systems carrying saltwater. The seats and disks diameter. of these valves are usually made of Monel, an 7. Chamfer the end of the shaft liberally to excellent corrosion- and erosion-resistant metal. allow space for weld deposits. Information on the commonly used types of 8. Make a stub of the same material as the valves and their constructionis provided in shaft. The stub should be 1/4 inch larger in Fireman, NAVEDTRA 10520-E. The infor- diameter and 3/8 inch longer than the damaged mation supplied here applies to gate and globe

15-16 5UG Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK valves but the procedures discussed can usually be adapted for repairing any type of valve.

Glove Valves

Closely inspect the valve seat and disk for erosion, cuts on the seating area, and proper fit of disk to seat. Inspect all other parts of the valve for wear and alignment and, if found defective,repairor renew. Generally, valve repair is limited to overhaul of the seat and disk. Overhauling of the disk and seat is usually done by grinding-in the valve seat and disk or by lapping the seat and machining the disk in a lathe. Where the disk and seat surfaces cannot be reconditioned by grinding or lapping, you must machine both the valve disk and valve seat in a 8.71 lathe. Figure 1511.Examples of spotted-In valve seats. If upon inspection, the disk and seat appear to be in good condition, spot them in to find out whether they actually are in good condition. process is also used to follow up all seat or disk machining work on a valve. SPOTTING-IN.The methodusedto To grind-in a valve, apply a small amount of visually determine whether or not the seat or grinding compound to the face of the disk, disk make good contact with each other is called insert the disk into the valve and rotate the disk spotting-in. To spot-in a valve seat, first apply a back and forth about a quarter turn. Shift the thin coating of prussian blue evenly over the disk-seat relation from time to time so that the entire machined face surface of the disk, then disk will be rotated gradually in increments insert the disk into the valve and rotate it a through several rotations. During the grinding quarter turn, using a light downward force at the process, the grinding compound will gradually same time. The prussian blue will adhere to the be displaced from between the seat and disk valveseatat points where the disk makes surfaces, so you must stop every minute or so to contact. Figure 15-11 shows what a correct seat replenish the compound. For best results when looks like upon spotting-in, and also shows what you do this, wipe both seat and disk clean and various kinds of imperfect seats look like upon then apply the compound to the disk face. spotting-in. After you have noted the condition When it appears that the irregularities have of the seat surface, wipe all the prussian blue off been removed, spot-in the disk to the seat as the disk face surface and apply a thin, even coat described previously. of prussian blue on the contact face of the seat When a machined valve seat and disk are and again place the disk on the valve seat and initially spotted-in, the seat contact will be very rotate the disk a quarter turn. Examine the narrow and located close to the edge of the resulting blue ring on the valve disk. If the ring is bore. Grinding-in, using finer compounds as the unbroken and of uniform width, the disk is in work progresses, causes the seat contact to good condition, if there are no cuts, scars, or become broader until a seat contact is produced irregularities on its face. If the ring is broken or as illustrated in figure 15-11. The contact area wavy, the disk is not making prop contact should be a perfect ring, covering approximately with the seat and must be machined. one-third of the seating surface, as shown in the correct seat in figure 15-11. GRINDING.Valve grinding is the method Avoid overgrinding. It will produce a groove of removingsmallirregularitiesfromthe in the seating surface of the disk and also will contacting surfaces of the seat and disk. This tend to round off the straight angular surface of

15-17 5u.-; MACHINERY REPAIRMAN 3 & 2 the seat. The effects of overgrinding can be 8. Do not lap more than is necessary to corrected only by machining the surfaces. produce a smooth and even seat. LAPPING.Lapping is the truing of a valve 9. Always use a fine grinding compound to seat surface by means of a cast iron lapping tool, finish the lapping job. shaped like and of exactly the same size as the disk for that particular valve. 10. Upon completion of the lapping job, By use of such a tool, you can remove spot-in and grind-in the disk to seat. slightly larger irregularities from the seat than it is possible to remove by grinding the disk to the Abrasive compound forgrinding-in and seat.(Seefig.15-12.)NEVER USE THE lapping-in valve seats and disks is available in VALVE DISK AS A LAP. Navy stock in four grades. The grades and the Below is a summary of the essential points recommended sequence of use are as follows: you must keep in mind while using the lapping tool GRADE USE

1. Do not bear heavily on the handle of the Coarse Forlapping-inseats lap. that have deepcuts andscratchesor 2. Do not bear sideways on the handle of extensive erosion. the lap. Medium For following up the 3. Shift the lap-valve seat relation so that coarse grade; may be the lap will gradually and slowly rotate around used also at the start the entire seat circle. o freconditioning process where damage 4. Check the working surface of the lap; if is not too severe. a groove wears on it, have the lap refaced. Fine Forusewhenthe 5. Use only clean compound. reconditioning process nears completion. 6. Replace the compound often. Microscopic fine Forfinishlapping-in 7. Spread the compound evenly and lightly. and for final grinding-in purposes.

REFACING.If the seat of a valve has been deeply cut, scored, or corroded to the extent that lapping will not correct the condition, it must be machined, or, in an extreme case, a new seat installed.

Many valves have removable seats which are threaded,welded, threaded and welded, or pressed into the valve body. In A of figure 15-13, the valve seating surface has been welded so that it has become an integral part of the valve body. In B of figure 15-13, the seating 11.353 surface has been welded so that it has become an Figure 15.12. Lapping tools. integral part of the seat ring. The seat ring is

15-18 5 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

28.262 Figure 15-13.Valve seat construction.

threaded into the body and seal-welded after RETAINER NUT HARDWHEEL installation.If theseatingsurface of A is damaged to the extent that it must be renewed, THRUST you need only to remove the existing weld WASHER material by machining and then rebuild the HANDWHEEL seating surface with successive deposits of new BUSHING weld material. After a sufficient deposit of weld BONNET material has been made, you can machine a new LOCATING seating surface.If the seating surface of B PIN requires renewal, you must first machine the seal weld from the ring and remove it from the valve body. A new seat ring may then be installed or theexistingseatsurface may be removed, rebuilt, and machined as previously described.

The actual machining operations for valve BODY seats and disks are described in chapter 8. After machining is completed, the seat and disk must SEAT BALL RETAINER be spotted-in, ground-in lightly, and respotted to SEAT RING BALL ensure that the valve disk-seat contact is as it should be. 47.196 Figure 15-14.Typical seawater ball valve.

Ball Valves theball rotates to a point where the hole through the ball is in line with the valve body Ball valves, as the name implies, are stop inlet and outlet. When you shut the valve, which valves that use a ball to stop or start the flow of requires only a 90° rotation of the handwheel fluid. The ball, shown in figure 15-14 performs for most valves, the ball rotates so that the hole the same function as the disk in a globe valve. is perpendicular to the flow openings of the When you turn the handwheel to open the valve, valve body, and the flow stops.

15-19 503 MACHINERY REPAIRMAN 3 & 2

Most ball valves are the quick-acting type located within the ball to give the valve a check (requiring only a 90° turn of a simple leveror valve feature. Figure 15-15 shows a ball-stop handwheel to completely openor close the swing-check valve with planetary gear operation. valve), but many are planetary gear operated. Ball valves are normally found in the following This type of gearing requires a relatively small systems on-board ship: seawater, sanitary, trim handwheel and operating force to operatea and drain, air, hydraulic and oil transfer. Repair fairly large valve. The gearing does, however, procedures forballvalves can be found in increase the time for opening or closing the PortsmouthProcessInstructionsdiscussed valve. Someballvalves have a swing-check below. In the case of the smaller types, repairs

INDICATOR INDICATOR INDICATOR ECCENTRIC DISK SHAFT SHAFT

HANDWHEEL

BEARING GREASE PLUG

BONNET

OPERATOR RING GEAR BODY GEAR INTERNAL GEAR BUSHINGS

BEARING

BEARING RETAINER

VALVE STEM RETAINING NUT

THRUST WASHERS GASKET ?IN RETAINING RING DISK

BUMPER

TAILPIECE

VALVE BODY BALL BALL SEATS

47.197 Figure 15-15.Typical ball stop swing-check valve for seawater service.

15-20 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK consistofpartreplacementsratherthan force against a partially open gate causes it to machining and rebuilding. vibrate, resulting in extensive damage to the valve.

There are two basic instructionv published Gate valves are classified as either rising stem NavalShipyardwhichare byPortsmouth (fig. 15-16) or nonrising stem valves (fig. 15-17). guidelines in the repair procedures of seawater On the nonrising stein gate valves, tile stem is ball valves and the balls themselves. In most threaded on the lower end into the gate. As you cases the most common repair to the ball itself is to pit fill any erosion and recoat the ball. The rotate the handwheel on the stem, the gate travels up or down the stein on the threads while guidelinesforthisprocessarecoveredin Instructionnumber the stem remains vertically stationary. This type PortsmouthProcess valve almost always has a pointer type indicator 4820-917-338D change 1 of 31 January 1977. The other instruction which covers the actual valve body is the PPI 4820-921-339B. The latter instruction applies to the repair of seawater ball valves when the waterway lip area has been YOKE SLEEVE corroded/eroded to the extent that its function NUT is reduced and serviceabilityis affected. The WHEEL repairof valveballwaterwaylipsinthis instruction applies only tostraight waterway YOKE valves whose stem connection does not enter the YOKE SLEEVE waterway and those without sea chest blow holes. This instruction also applies to the repair STEM of the stem cavity and 0-ring sealing areas and to seawater ball valves whose back seat areas are corroded and eroded to the extent that leakage between the valve seat and back seat areas exceeds allowable leakage requirements. The GLAND detailed repair steps are in Portsmouth Process BONNET InstructionNumber 4820-921-339Bof BUSHING 24 June 1977 which cancels number 4820-921 - PACKING 339A. BONNET

BODY BONNET BOLTS

Gate Valve BODY

GATE Gate valves are used when a straight line flow of fluid with minimum flow restriction is BODY SEAT desired. Gate valves are so named because the RINGS part (gate) which either stops or allows flow throughthevalveacts somewhatlikethe opening or closing of a gate. The gate is usually GUIDE RIBS wedge shaped. When the valve is wide open, the gate is fully drawn up into the valve, leaving an opening for flow through the valve which is the same size as the pipe in which the valve is installed.Gatevalvesarenotsuitablefor 11.317X throttling purposes since the control of flow Figure 15-16.Cutaway view of gate stop valve (rising would be difficult due to turbulence, and fluid stem type).

15-21

517 MACHINERY REPAIRMAN 3 & 2

1413

13 14

II 21 NOT USED ON 2"S1ZE 9 8 0 7 22 I0 23 7

5

3 ---2

LIST OF PARTS PART NO. NAME OF PART PART NO. NAME OF PART I BODY 13 HANDWHEEL WASHER 2 SEAT RING 14 HANDWHEEL NUT 3 GATE 15 BONNET STUD 4 STEM 16 BONNET STUD NUT 5 BONNET GASKET 17 STUFFING BOX GASKET 6 BONNET 18 INDICATOR PLATE 7 STUFFING BOX 19 LOCK WASHER 8 PACKING 20 INDICATOR PLATE SCREW 9 GLAND 21 INDICATOR NUT 10 GLAND STUD 22 STUFFING BOX STUD II GLAND STUD NUT 23 STUFFING BOX STUD NUT 12 HANDWHEEL

38.118 Figure 15-17.Cross-sectional views of gate stop valves (nonrising stem type).

threaded onto the upper end of the stem to the stem rise and lower together as the valve is indicate valve position. operated. With this basic information on the principles of the gate valve, you are ready to The rising stem gate valve (fig. 15-16) has learn about repair procedures and manufacturing the stem attached to the gate, and the gate and of repair parts.

15-22 512 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

Defects such as light pitting or scoring and A Leslie constant-pressure pump governor imperfect seat contact can be corrected best by for a main feed pump is shown in figure 15-18. lapping. Use a lapping tool designed for the type The governors used on fuel oil service pumps, of valve to be reconditioned. NEVER use the lube oil service pumps, fire and flushing pumps, gate as a lap. and various other pumps are almost identical. The chief difference between governors used for The lapping process is the same for gate different servicesisin the size .of the upper valves as for globe valves, but you turn the lap diaphragm. A govern used for a pump that by a handle extending through the inlet or operates with a high discharge pressure has a outlet end of the valve body. Insert the lapping smaller upper diaphragm than one used for a tool, minus the handle, into the valve so that pump thatoperateswitha low discharge you cover one of the seat rings. Then attach the pressure. handle to the lap and begin the lapping work. You can lap the wedge gate to a true surface, Two opposing forces are involved in the using the same lap that you used on the seat operation of a constant-pressure pump governor. rings. In some cases when a gate is worn beyond Fluid from the pump discharge, at discharge repair and a shim behind the seat will not give a pressure, is led through an actuating line to the proper seat, it is possible to plate the gate or space below the upper diaphragm. The pump seat,orboth,asdescribed in chapter14, discharge pressure exerts an UPWARD force on Electroplating. (Note: Shim has to be applied theupperdiaphragm.Opposingthis,an behind both seats to maintain proper angle.) It is adjusting spring exerts a DOWNWARD force on also possible to weld repair the damaged gate the upper diaphragm. and then machine it to its original specifications in either a mill or lathe, using an angle plate or When the downward force of the adjusting fiXture. One of the advantages of plating over spring is greater than the upward force of the the weld repair method is that no heat is pump discharge pressure, the spring forces both involved in the selective brush plating method. the upper diaphragm and the upper crosshead Building up metal by welding always heats the downward. A pair of connecting rods connects surfaces being repaired and can cause loss of theuppercrossheadrigidlytothelower temper or other weaknesses in the metal. crosshead, so the entire assembly of upper and lower crossheads moves together. When the crosshead assembly moves downward, it pushes Constant-Pressure Governor the lower mushroom and the lower diaphragm downward. The lower diaphragm is in contact with the controlling valve. When the lower Many turbine driven pumps are fitted with diaphragm is moved downward, the controlling constant-pressure pump governors. A constant- valve is forced'down and open. pressure pump governor maintains a constant The controlling valve is supplied with a small pumpdischargepressureundervarying amount of steam through a port from the inlet conditions of load. The governor, which is side of the governor. When the controlling valve installed in the steam line to the; pump, controls is open, steam passes to the top of the operating the amount of steam admitted to the driving piston. The steam pressure acts on the top of the turbine, thereby controlling the pump discharge operating piston, forcing the piston down and pressure. opening the main valve. The extent to which the main valve is opened controls the amount of Twotypesofconstant-pressurepump steam admitted to the driving turbine. Increasing governors are used by the Navythe Leslie and the opening of the main valve therefore increases the Atlas. The two types of governors are very the supply of steam to the turbine and so similar in operating principles. Our discussion is increases the speed of the turbine. based on the Leslie governor, but most of the The increasedspeedof the turbineis information applies also to the Atlas governor. reflected in an increased discharge pressure from

15 -23i MACHINERY REPAIRMAN 3 & 2

HANDWHEEL ADJUSTING SCREW

LOCK NUT

STEAM CHAMBER ADJUSTING SPRING

DIAPHRAGM DISK (UPPER MUSHROOM)

UPPER DIAPHRAGM

ACTUATING LINE FROM DISCHARGE SIDE OF PUMP NEEDLE VALVE

INTERMEDIATE DIAPHRAGM .77° 9PIP"r DIAPHRAGM STEM CROSSHEAD CONNECTING ROD 414 (LOWER MUSHROOM) Nw\ DIAPHRAGM STEM CAP 7isk DIAPHRAGM STEM GUIDE (INTERMEDIATE MUSHROOM) , 11:\,e/ CONTROLLING VALVE BUSHING LOWER DIAPHRAGM CONTROLLING VALVE

CYLINDER LINER CONTROLLING VALVE SPRING OPERATING PISTON

STEAM INLET STEAM OUTLET He*(TO TURBINE) MAIN VALVE

MAIN VALVE SPRING

STEM (FOR BYPASS)

INDICATOR PLATE

HANDWHEEL( FOR BYPASS)

38.90 Figure 15.18. Constant - pressure governor for main feed pump.

15-24 514 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

the pump. This pressure is exerted against the it finds the new position required to maintain underside of the upper diaphragm. When the pump discharge pressure at the new load. pump discharge pressure has increased to the point that the upward force acting on the A pull-open device, consisting of a valve underside of the upper diaphragm is greater than stem and a handwheel, is fitted to the bottom of the downward force exerted by the adjusting the governor. Turning the handwheel to the spring,theupperdiaphragmismoved open position draws the main valve open and upward. This action allows a spring to start allows full steam flow to the turbine. When the closing the controlling valve which in turn allows main valve is opened by means of this bypass the main valve spring to start closing the main arrangement, the turbine must be controlled valve against the now-reduced pressure on the manually.Underallnormaloperating operating piston. When the main valve starts to conditions, the bypass remains closed and the close,the steam supplytotheturbineis pump discharge pressure is raised or lowered, as reduced, the speed of the turbine is reduced, and necessary,byincreasingordecreasingthe the pump discharge pressure is reduced. tension on the adjusting spring.

At firstglance,itmight seem that the CONTROL AND MAIN VALVE.If there is controlling valve and the main valve would be leakage in the generator through the control constantly opening and closing and the pump valve or its bushing, steam will flow to the top discharge pressure would be continually varying of the operating piston, opening the main valve, overawiderange. This does not happen, and holding it open, even though there is no however, because the governor is designed to tension on the adjusting spring. The main valve prevent excessive opening or closing of the must be able to close off completely or else the controlling valve. An intermediate diaphragm governor cannot operate properly. The only bears against an intermediate mushroom which remedy is to disassemble the governor and stoi. in turn bears against the top of the lower the steam leakage. In most instances, you must crosshead. Steam is led from the governor outlet renew the control valve. If the leakage is through to the bottom of the lower diaphragm and also the bottom of the bushing and its seat, you must throughaneedle valve to the top of the lap the seat. A cast iron lap is best for this type intermediatediaphragm. A steamchamber of work. provides a continuous supply of steam at the Rotate the lap through a small angle of required pressure to the top of the intermediate rotation, lift it from the work occasionally, and diaphragm. move to a new position as the work progresses. This will ensure that the lap will slowly and Any up or down movement of the crosshead gradually rotate around the entire seat circle. Do assembly is therefore opposed by the force of not bear down heavily on the handle of the lap. thesteampressureactingoneitherthe Replace the compound often, using only clean intermediate diaphragm or the lower diaphragm. compound. If the lap should develop a groove or Thewholearrangementservestoprevent cut, redress the lap. Lapping should never be extreme reactions of the controlling valve in continued longer than necessary to remove all responsetovariationsinpump discharge damaged areas. pressure. When you are installing the control valve and Limiting the movement of the controlling its bushing, remember that the joint between the valve in the manner just described reduces the bottom ofthebushing anditsseatisa amount of hunting the governor must do to find metal-to-metalcontact.Installthebushing eachnewposition.Underconstant-load tightly, and when it is all the way down, tap the conditions, the controlling valve takes a position wrench lightly with a hammer, to ensure a that causes the main valve to remain open by the steamtight joint. required amount. A change in load conditions When the controlling wive is installed, you causes momentary hunting by the governor until must check the clearance between the top of the

15-25 i5 MACHINERY REPAIRMAN 3 & 2

valve stem and the diaphragm. It is absolutely start the reassembly, be sure that all ports in the mandatory that this clearance be between .001 top cap and diaphragm chamber are free of dirt and .002 inch (fig. 15-19). If the clearance is less and other foreign matter. Check to ensure that than .001 inch, the diaphragm will hold the the piston rings are free in their grooves. The control valve open, allowing steam to flow to cylinder liner must be smooth and free of the main valve at any time the throttle valve is grooves, pits, or rust. open. If the, clearance is more than .002 inch, When installing the cylinder liner, make the diaphragm will not fully open the control certain that the top of the liner does not extend valvewhich means that the main valve cannot above the top of the valve body. The piston open fully, and the unit cannot be brought up to must work freely in the liner; if there is binding, full speed and capacity. the governor willnot operate satisfactorily. When the main valve seating area is damaged, Renew the controlling valve spring and the main it must be lapped in by the same process. valvespringif theyareweak, broken or ALWAYS lap in the main valve with the piston corroded, or if they have taken a permanent set. in the cylinder liner to ensure perfect centering. If necessary, renew all diaphragms; if you use If the damage to the seating surfaces is the old diaphragms, install them in their original excessive, you must install new parts. Use only position; do not reverse. parts supplied by the manufacturer, if available. Followtheinstructionsinthemanu- TOP CAP.If the top flange of the top cap facturer'stechnicalmanualinreassembling of the governor becomes damaged, you must be the governor. All clearances must be as designed extremely careful machiningit.Consult the if the governor is to operate satisfactorily. You manufacturer's technical manual for the correct must check each moving part carefully to ensure clearances. (See fig. 15-19.) freedom of movement. All seating surfaces must be square with the When the governor is reassembled, test it as axis of the control valve seat threads and must soonaspossiblesothatyou can make have the smoothest possible finish. Before you corrections, if necessary.

"

96.36 Figure 16-19.Critical dimensions of Leslie top cap. 15-26 5i 6 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

Double Seated Valves HAMMER-BLOW WHEEL Depending on the extent of damage to the ON 3 AND 4-INCH SIZES disk of a double seated valve, you can lap or weld-repair it and remachine it to fit the body. YOKE BRUSHING The normal seat angles remain the same as for YOKE globe valves and the spotting-in procedure will GLAND FLANGE be the same. Most valve disks can be held on a GLAND spud or mounted on a mandrel and can be cut in BONNETLG OOKING RIN the same manner as a globe valve. In this case as AND BONNET in the others, it is best to consult local quality assurance directives and local procedures in the SEAL RING STEM repair of this type of valve. Also, in most cases DISC AND MSC the blueprints will show "ND" (no deviations) STEM RING EYE BOLT and must be closely adhered to, as far as type of "Ae RING weld and quality. In all cases shop LPO's should li*t///4L. BODY be able to provide the necessary information. WV.NOos<

Pressure Seal Bonnet Globe Valves Assembling High-Pressure Steam Valves The bonnet joint of a high-pressure seam In many cases you may be required to repair valve is always made up with a metallic or a pressure seal bonnet globe valves. This type of flexible gasket and high-temperature-use alloy valve (fig. 15 -20) is usually the welded bonnet stud bolts and nuts. When you assemble such a type, and you willbeinvolvedinasfar as valve, be sure that you use the correct kind of machining the bonnet seal area to specifications gasket and stud bolts. If you are the least bit provided by either the applicable blueprint or doubtful of what you should use in a particular the Hull Technician doing the welding. This valve, ask your leading petty officer. basic type valve is used in steam systems; it is There are two ways to identify a high- also commonly found in the nuclear systems in temperature-use alloy stud bolt: (1) the thread submarines and submarine tenders. This type of runs the entire length of the body and one end valve repair is also referred to as canopy seal of the bolt has a small center hole recess and

15-27 5i7 MACHINERY REPAIRMAN 3 & 2

(2) the bolt will have either an "H" or an "A" instruction on correct tension for different sizes stamped on one end. of stud bolts. High-temperature nuts have either an "H" or "A" stamped on the crown. If you do notsee such an identification on a nut, do not use it on Testing Valves a high-pressure valve.

When assemblingavalve,useantiseize After a valve has been overhauled in the compound on the stud bolt threads, and always shop, itis standard practice to test it under be sure to back the disk away from the seat hydrosLac pressure to prove the tightness of before tightening any of the bonnet nuts. In the seat and the bonnet joint. Figure 15-21 setting up on bonnet flange nuts,alternate shows a Machinery Repairman in the process of approximately 180° and 90° from the starting applying a hydrostatic test to a high-pressure point until you have all of them set up evenly steam valve. In this particular setup, the valve is and fairly tight. For final all-round setup on the held on a thick rubber gasket by U-clamps and nuts, use a strain gage to measure for correct water delivered under pressure from a hydraulic tightening tension or a micrometer to measure test pump will be led into the bottom of the elongation of the studs to compute the tension. valve from a connection underneath the test Your leading petty officer can give you practical stand.

r

28.283 Figure 15-21.Applying hydrostatic test to a high-pressure steam valve.

15-28 51 S Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

After applying a test pressure to the lower these pumps are the ones that a Machinery part of the valve, the valve will be placed with Repairman will usually be required to repair. the other flange down to test the bonnet joint. Figure 15-22 is a sketch of the internal parts When testing valves hydrostatically, be sure of a centrifugal pump. Look at the arrangement to use the specified test pressure. Too low a of the impeller, casing wearing rings,' impeller pressure will not prove the tightness of the valve wearingrings,shaft,andshaftsleevesin and too high a pressure may cause damage to the particular. valve. In a centrifugal pump, the portion of the shaft in the way of the packing gland and the casing-impeller sealing areas are subject to wear REPAIRING PUMPS in operation. They must be renewed from time to time, to maintain the operating efficiency of A description of the common types and uses the pump. of pumps on-board ship is provided in Fireman, To prevent having to renew the entire shaft NAVEDTRA 10520-E. The following discussion solely because of wear in the packing gland area, is limited to repair of centrifugal pumps because shafts in centrifugal pumps are often provided

EXHAUST STEAM INLET

C')VERNOR VALVE

2ND STAGE IMPELLER

IMPELLER WEARING RING 1ST STAGE IMPELLER CASING WEARING RING SHAFT SLEEVES SHAFT

GOVERNOR

THRUST BEARING

CARBON PACKING

OIL PUMP OIL TANK T,

38.109 Figure 16 -22. Two -stage main feed pump. 15-29j MACHINERY REPAIRMAN 3 & 2 with tightly fitting renewable sleeves. To offset before you can install a new one. On centrifugal the need for renewing or making extensive pumps, the shaft sleeve is a snug slip-on fit, repairs to the casing and impeller, these two butted up against a shoulder on the shaft and partsalso have renewable wearing surfaces, held securely in place with a nut. In the latter called the casing wearing ring. and impeller pumps, the sleeve-shaft shoulder joint is usually wearing rings. You can seethearrangement made up with a hard fiber washer to prevent clearly in figure 15-23. leakage of liquid through the joint and out of the pump between sleeve and shaft. When it is necessary to renew these parts, The impeller wearing ring is usually lightly the rotor assembly, consisting of the pump press-fitted to the hub cc the impeller and keyed shaft, the impeller and its wearing ring, and the in with headless screws (also referred to as casing rings, is usually brought into the shop. "Dutch keyed"). To remove the worn ring, The method of replacing these parts is described withdraw the headless screws or drill them out in the following paragraphs. and then machine the ring off in a lathe. Theamounto fdiametricalrunning The repair parts generally are available from clearances between the casing rings and impeller the ship's allowance, but often you may need to ringsaffects the efficiency of a centrifugal turn them out in the shop. Before you can pump. Too much clearance will let an excessive proceedwiththeserepairs,consultthe amount of liquid leak back from the discharge ra a nufacturer'stechnicalmanualandthe side to the suction side of the pump. Insufficient app)Ca hl e blueprintstogetthecorrect clearance willcause the pump to "freeze." information on vital clearances and other data. Before you install a new wearing ring on the In some pumps, the shaft sleeve is pressed impeller, measure the outside diameter of the onto the shaft tightly with a hydraulic press, and impeller hub, the inside and outside diameters of you must machine off the old sleeve in a lathe theimpellerwear ring,andthe inside

LIQUID RADIAL SEAL CLEARANCE

STUFFING BOX (INTEGRAL WITH CASING) 2 ow IMPELLER

..:veneeneeammeamemeadOMIR SHAFT SLEEVE

'e-WZOOMOCCMVat.M.

IMPELLER WEARING STUFFING RING BOX PACKING CASING WEARING GLAND LANTERN THROAT RING RING BUSHING

28.35 Figure 16.23. Stuffing box on centrifugal pump.

15.30 4i1 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK diameter of the casing ring. (See fig. 15-24.) If (The casing rings may be chucked in a 4-jaw the measurements do not agree with the fit and chuck but there is danger of distorting the ring if clearance data you have on hand, ask your this is done.) leading petty officer for instructions before proceedinganyfurther.Sometimesitis 2.Take a light cut on the inside diameter necessary to take a light cut on the inside of the casing ring to clean up the surface. Do diameter of the impeller ring to get its correct this to all casing rings. press fit on the impeller hub: The difference between the outside diameter of the impeller 3. Mounttheshaftassembly between wearing ring and the inside diameter of the centers or in a chuck and align with the lathe casing wearing ring is the diametrical running axis. clearance between the ring. If this clearance is too small, correct it by taking a cut on either the 4.Machine away the impeller wearing rings. outside diameter of the impeller ring or the Be careful not to cut into the impeller. inside diameter of the casing ring. Another thing to check is the concentricity of the two rings; if 5.Take a light cut on the packing sleeves to they do not run true, you must machine their. clean up the surfaces. mating surfaces so that they do run true, bearing in mind, of course,to keep the specified 6. Remove the shaft assembly from the diametrical clearance. lathe. When a pump like the one shown in figure 15-22 needs repairs, usually only the shaft 7. Make the impeller rings. The size of the assembly and casing wearing rings are brought to inside diameter of the impeller rings should theshop. To renew the wearing rings and provide a press fit on the impeller; the outside resurface the !Jacking sleeves of the pump shown diameter should be slightly larger than the inside in figure 15-22, take the following steps: diameter of the casing rings.

1. Clamp the casing wearing ring on a 8.Press the impeller rings on the impeller faceplate and align the circumference of the ring and lock in place with headless screws, if so concentrically with the axis of the lathe spindle. stated on blueprint. 9. Mount the shaft assembly back in the lathe and machine the diameter of the impeller rings to provide the proper clearance between impeller rings and casing rings. Blueprints and/or 1C.... IMPELLER WEARING RING technical manuals will list the desired clearance in one of two ways: (1) If diametrical clearance is used, that is the total amount of clearance required; (2) if it is listed as radial clearance, the amount desired has to be doubled to get diametrical clearance.

MACHINE SHOP MAINTENANCE

IMPELLER WITH IMPELLER CASING WEARIN RING The ship in which you serve and the shop in WEARING RING which you work were designed to accomplish a particular mission or job. As an MR3 or MR2, 75.281X you will be expected to assist in the proper Figure 15-24.Impeller, impeller wearing ring, and casing maintenance and preservation of the machines wearing ring for a centrifugal pump. and spaces you use. Generally, you can give a

15-31 (.44 MACHINERY REPAIRMAN 3 & 2

workshop one good look and tell whether it is Avoid scoring the platen of a planer, efficient and well run. The Ship's Maintenance drilling holes in the table of a drill press, or Material Management (3-M) System has been gouging thevise or footstock of a milling implemented by the Navy as an answer to the machine. ever present problem of maintaining a high degree of operational readiness. A thorough Do not us:. the table of any machine for studyof Military Requirements for Petty a workbench. Officers 3 & 2, NavPers 10056-D, will give you all the information you need on the 3-M System. When using a toolpost grinder on a lathe, Although the 3-M System is designed to cover the ways and other finished surfaces to improve the degree of readiness, its effectiveness protect them against grit. and reliability are dependent upon you, the individual.Theaccuracy withwhich you Seethatpneumaticpower-driven performyourwork,alongwith neatand handtools are lubricated after each 8 hours of complete recording of required data on the operation or more often where found necessary. prescribed forms is one of the keys to the degree ofreadinessofyourship.Remember PREVENTIVE MAINTENANCE(scheduled Before taking an electric power-driven checks)willleadtolessCORRECTIVE handtoolfromthetoolroom,examineit MAINTENANCE (repair of equipment). Control carefully for mechanical and electrical defects over rust and corrosion will be a major problem. and ensure that theelectrical safetytagis Equipment used often is not likely to "freeze up-to-date before using. up," but machinery which is seldom used may fail to operate at a crucial moment. It is a good Whensecuringforsea,take all pllicy to check and operate all shop machinery precautionstoensurethatmachineryor immediately after the weekly lubrication. components will not sway or shift with the Therewillberustfilmtroubleinall motion of the ship. The precautions should climates, but it will occur more frequently in the include the following: tropics because of humidity (moisture). All bare metal surfaces should be kept clean and bright, a. In securing top-heavy equipment such and a light coat of machine oil should be applied as a radial drill press arm, lower it to rest on the to protect them. The rust prevention program table or base of the machine and then make sure should be a part of your daily cleanup routine. that it is locked and blocked securely. Using an approved rust preventive compound b. Secure chain falls, trolleys, overhead will help prevent rusting of decks and bare metal cranes, and other suspended equipment, such as surface., and machinery parts. counterweights on boring mills and drill presses. Itis sometimes said that a machine tool operator can be judged by the condition of his tools, machines, and spaces. Good maintenance practices will save you many hours of oxtra work.Somegoodprecautionsforthe maintenance of machinery are listed below:

Before applying power to a machine, see thatthe machineis ready for starting. For example, move the carriage of a lathe by the hand feed to ensure that all locking devices have been released. 1.21C Do not lay work or handtools on the Figure 15-25.Removing a broken stud with vise-grip ways of a machine. pliers. Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

c. Secure tailstocks of lathes. possible to back it out with light blows of a d. Secure spindles of horizontal boring prick punch or center punch. However, if the mills. bolt was broken due to rusting, this method will e. Protect and secure tools stowed in not remove it.If you cannot remove it by cabinets or drawers. Secure drawers and cabinet carefully punching first on one side and then the doors. other, use a screw and bolt extractor. (See fig. 15-27B.) When using this extractor, file the broken REMOVING BROKEN BOLTS AND STUDS portion of the bolt to provide a smooth surface at the center for a punch mark, if possible. Then When you must remove a broken bolt or carefully center punch the exact center of the stud,flood the part being worked on with bolt. (See fig. 15-27A.) plenty of penetrating oil or oil of wintergreen. Refer to table 15-1 To select the proper drill Time permitting, soak the area for several hours to use according to the size of the broken bolt or overnight. A week's soaking may loosen a that you are trying to remove. If possible, drill bolt which would otherwise have to be drilled through the entire length of the broken bolt. out. Thencarefullywork some penetratingoil If enough of the broken piece protrudes, through the hole so that itfillsthe cavity take hold of it with vise-grip pliers, as shown in beneath the bolt and has a chance to work its figure 15-25, and carefully try to ease it out. If way upward from the bottom of the bolt. The you cannot turn the bolt, further soaking with more time you let the penetrating oil work from penetrating oil may help. Or try removing the both ends of the broken bolt, the better are pliers and jarring the bolt with light hammer your chances of removing it. blows on the top and around the sides. This may In drilling a hole in a stud that has broken loosen the threads so that you can remove the off below the surface of the piece which it was belt with the vise-grip pliers. holding (fig. 15-28A), use a dell guide to center If a bolt has been broken off flush with the the drill. This method may be preferred rather surface as shown in figure 15-26, it is sometimes than a center punch mark. After you have drilled the hole and added penetrating oil and let it soak, put the spiral end of the screw and bolt extractor into the hole. Set it firmly with a few light hammer blows and securethetapwrench as shown infigure 15-28B. Carefully try to back the broken bolt

44.188 44.20BB.2 Figure 16-28.Removing a broken bolt with a prick Figure 15-27.Screw and bolt extractors for removing punch. broken studs.

15- -32 MACHINERY REPAIRMAN 3 & 2

Table 15-1.Chartfor Screw and Bolt Extractors

Extractor Used For Use Drill Size Nominal Screw Dia., Inches Size No. Overall Length, Nominal Pipe Inches And Bolt Size, Inches Size, Inches 1 2 3/16-1/4 5/64 2 23/8 1/4-5/16 7/64 3 211/16 5/16-7/16 5/32 4 3 7/16-9/16 1/4 5 33/8 9/16 -3/4 1/4 17/64 6 33/4 3/4 -1 3/8 13/32 7 41/8 1 - 1 3/8 1/2 17/32 8 43/8 13/8- 1 3/4 3/4 13/16 9 45/8 13/4 - 2 1/8 1 11/16 10 5 21/8- 2 1/2 11/4 15/16 11 55/8 21/2 - 3 11/2 19/16 12 61/4 3 - 3 1/2 2 115/16

44.220

DRILL TAPt EXTRACTOR GUIDE WRENCH

A B

44.2000 Figure 15-28..Removing a stud broken off below the 44.20DD surface. Figure 15.29. Removing an Allen head capscrew with a bolt extractor. outofthehole.Turntheextractor counterclockwise. (This type of extractor is removal, carefully grind off the end of the designed for right-hand threads only.) extractor so that it will not bottom before the Sometimes you can use a screw and bolt spiral has had a chance to take hold. Figure extractor to remove an Allen head capscrew 15-29 shows this end clearance. In doing this when the socket has been stripped by the Allen grinding operation, be very careful to keep the wrench. (Sec fig.15-29.) When attempting this temperature of the extractor low enough so that

15-34 5:.!,1 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK you can handle the tip with your bare hands. If the hardness is drawn from the tip of the extractor by'Overheating during the grinding, the extractor will not take hold.

REMOVING A BROKEN BOLT AND RETAPPING THE HOLE

To remove a broken bolt and retap the hole, file theboltsmooth,ifnecessary,and A B centerpunch it for drilling. Then select a twist drill which is a little less than the tap-drill size 44.189 for the particular bolt that has been broken. As Figure 15-31.Removing broken bolt and retapping hole shown in figure 15-30, this drill will just about to larger size. but not quite touch the crests of the threads in the threaded hole or the roots of the threads on the threaded bolt. Carefully start drilling at the away andtheoriginalthreadshavebeen center punch mark, crowding the drill one way, restored. or the other as necessary so that the hole will be In cases where the identical size of capscrew drilled in the exact center of the bolt. or bolt is not necessary as a replacement, center The drill in figure 15-30 has almost drilled punch and drill out the old bolt with a drill the remaining part of the bolt away and will larger than the broken bolt, as shown in figure eventually break through the bottom of the 15-31A. Tap the hole first, and then finish it bolt. When this happens, all that will remain of with a bottoming tap as shown in figure 15-31. the bolt will be a threaded shell. With a prick Replace with a larger size capscrew or stud. punch or other suitabletool, chip out and remove the first two or three threads, if p -sible, REMOVING A BROKEN at the top of the shell. Then carefully start a TAP FROM A HOLE tapered tap into these several clean threads and continue tapping until the shell has been cut To remove a broken tap from a hole, generously apply penetrating oil to the tap, working it down through the four flutes into the hole. Then, if possible, grasp the tap across the flatswith vise-grippliers.This operationis shown in figure 15-32. Carefully ease the tap out of the hole, adding penetrating oil as necessary.

44.20EE 1.21D Figure 15-30.Removing a broken bolt andretapping Figure 15-32.Removing a broken tap with visegrip hole to same size. pliers.

15-35

Pa. MACHINERY REPAIRMAN 3 & 2

If the tap has broken off at the surface of the work or slightly below the surface of the PLUG WELD work, the tap extractor shown in figure 15-33 AREA HEX NUT may remove it. Again, apply a liberal amount of penetrating oil to the broken tap. Place the tap extractor over the broken tap and lower the BROKEN upper collar to insert the four sliding prongs /TAP down into the four flutes of the tap. Then slide the bottom collar down to the surface of the work so that itwill hold the prongs tightly against the body of the extractor. Tighten the tap wrench on the square shank of the extractor and carefully work the extractor back and forth 44.192 to loosen the tap. You may need to remove the Figure 15-34.Using a plug weld to remove a broken t extractor and strike a few sharp blows with a small hammer and pin punch to jar the tap loose.Thenreinsertthetap remover and which you may be able to remove the tap more carefully try to back the tap out of the hole. easily. If the heating is too slow, the tap will expand with the adjacent metal of the work and Each size of tap will require its own size of there will be no loosening effect. tapextractor. Tap extractors come inthe following sizes: 1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 3/4, 7/8 and 1 inch. MAKING PISTON RINGS When a tap extractor will not remove a To make a cast iron piston ring, select a broken tap, you may be able to do so by the billet of sufficient size to permit removal of following method: Place a hex nut over the tap surface defects. For example, in making a ring (fig. 15-34), and weld the nut to the tap. Be sure that has a 10-inch outside diameter and a 9-inch to choose a nut with a hole somewhat smaller inside diameter, use a billet with an outside than the tap diameter to reduce the possibility diameter of 11 inches and an inside diameter of of welding the nut and the tap to the job itself. 8 inches. A billet this size has a wall thickness of Allow the weld to cool before trying to remove 1 1/2 inches and will allow removal of 1/2 inch the tap. When the nut, tap, and job have come of metal from the inside surface and 1/2 inch of to room temperature, it is often helpful to heat metal from the outside surface. To make the quickly the immediate area around the hole with ring, proceed as follows: an oxyacetylenetorch.This quick heating expands the adjacent metal of the work after 1.Mount the billet in a chuck on the lathe.

2.Face the end. SLIDING BROKEN UPPER TAP PRONG 3.Rough bore and then finish bore to the COLLAR inside diameter of the ring. Bore a sufficient distance into the billet to make the desired width of the ring or rings. BOTTOM SQUARE COLLAR SHANK 4.Rough turn the outside of the billet to a diameter that is 0.010 inch larger per inch than the bore of the cylinder into which the ring is to 44.191 be fitted. For example, for a 10-inch cylinder Figure 15-33.Removing a broken tap with a tap bore, the rough turn diameter would be 10.100 extractor. inches.

er; Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK INMINIVEIN

5.Cut off the ring to width with a parting lathe is geared in the same manner as for screw tool. cutting.Table15-2indicates which gearing should be used. The figures in the body of the 6.Split the ring with a 45° cut, using a table give the number of threads per inch for hacksaw. Place a piece of chart paper in the cut which the lathe should be geared to wind coil and then wrap a piece of wire around the springs of a given wire gage. The figures in the circumference of the ring and draw it up until column headed "A" are for closewound tension the ends butt up snugly. springs, while the figures in the columns headed "B" are for compression springs. Assume as an 7.Mount the ring on a faceplate to finish example, that you must wind a compression turn to exact cylinder bore size. Place faceplate spring of No. 10 Brown and Sharpe gage wire. clamps on the inside of the ring to prevent From the table, you will note that this spring interfering with the operation. Place a piece of should have four and one-half coils per inch, or paper between the ring and the surface of the in other words that the lathe should be geared faceplate to keep the ring from slipping and also the same as for cutting four and one-half threads to keep the tool from cutting into the faceplate per inch. when turning. When you have centered the ring on the faceplate and taken up the clamps Table 15-3 gives data for winding piano wire securely, remove the binding wire, and proceed tension springs and may be best explained by an with the finish turning operation. example. Assume that you must wind three different springs; the first to be wound from 0.035-inch wire to fit in an 11/16-inch hole, the SPRING WINDING second to be wound from 0.040-inch wire to fit a 3/8-inch hole, and the third to be wound from The methods and tools used for winding or 0.060-inch wire to be a sliding fit on a 1/2-inch coiling springs vary greatly in form and also in diameter shaft. The table shows the proper sizes regard to productive capacity. The method used of mandrels for winding to be as follows: for the ordinarily depends upon the number of springs first spring 0.562 inch; for the second spring, requited and to some extent upon their form. 0.250 inch; and for the third spring, 0.437 inch. When a comparatively small number of springs In the latter case, 0.011 inch is allowed for play are needed in connection with repair work, etc., between spring and shaft. The wire sizes given in it is common practice t, wind them in a lathe; the table conform to the English music wire whereas when springs are manufactured in large gage. quantities, special machines are used. In all cases when the mandrel diameter is Sprir Is are often .a(lewith an "initial larger than 3/8 inch, the mandrel is mounted in tension's wnich caus the coils to be drawn a lathe chuck. Mandrels less than 3/8 inch in tightlytogethc, resultissecuredby diameterare mounted in adrillchuck. In twisting the wire as the spring is wound. A fastening the wire in a lathe chuck, one jaw is common example of a spring of this type is the usually loosened. When the mandrel is driven by ordinary screen door spring. When in a static a drill chuck, place the wire between the jaws condition (as before being installed on a door), and the mandrel. If a long spring is required, use such springs will not begin to deflect as soon as a mandrel of corresponding length, which is the load is applied, it being necessary to first ground to an angle of 60° at the end to fit into a overcometheinitialtension alreadyin the female dead center for support. Place the wire in spring. a bench lathe boring tool holder or a V-holder in the toolpost. Place a piece of brass about 1/8 TABLES FOR SPRING WINDING inch by 1/2 inch by 3 inches between the wire and the toolpost screw. File a V-shaped groove When springs are to be wound by using a in the brass to hold the wire in place. File the lathe instead of a spring-coiling machine, the groove in the lengthwise direction of the brass

15-37 t... MACHINERY REPAIRMAN 3 & 2

Table 15-2.Gearing Lathe for Winding Wire Coil Springs

Tension Spring r Compression Spring -- II

Brownrown 4e& Birming- Washburn OldEnglish Num- ham or Trenton Sharpe & Mocn Iron Co. Prentiss Brass Man- ber of Stub's Mfg. Co. Wire ufacturers' Gage II I II I II I II I IIIII

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- - mata *Plan optnuo quila ovigui opinno 4anN unla 411PN MOM p =viala =via io .ualia PAK =Who .tea Jag JO p old 'v 10 mom 41131( P Y3 imp lulas upds ossui imp am/ 4muit "VA /Mg' qupg8 lapse allAi sKragl seqPul 'NMI *Mai *MR 11WAI 1334313I ofgo o6g'o ggf'o gz ogfo'o gsto 691'0 Lgto eg o6too gzf'o fff'o Lgto gz ogfo'o the° gft'o tffo Cs o61oo thes) ogto gz g6to ogfo'o Lfto ooSo g69o eg o6too Lft fgt° £99, 91 0910.0 clos0 999.0 199.0 CS o610o ggg'o oofo offo 91 ogfo'o ggf'o 919.0 9140 fc o61oo ggS'o fzgo fgg'o 91 ogfo'o fgro ooLo g6L'o fc o6to fgg'o fggo ffLo 91 ogfoo ca° zhto LLto ts ago° ofso g6go ggfo Li ogfo'o fLfo grto tOfo tg offoo gito gft'o tfto Li ogfoo Let.° toSo ozgo ts offoo fhto fgto 66to 41 ogfoo oofo ggfo tLco tt ottoo Lfto ggt'o ggf'o 42 ogfoo ggfo ofg'o 9140 tg offoo oofo tff'o otgo Li ogfoo fgro goLo gog'o tg ago° ggf'o . ftgo z69o Li ogero W.° theo ggto fs ogfo'o fggo ggg'o 19Lo Lz ogeo 9L10 ztO'o effo fg ogfo'o ofgo gz t6go thfo ootoo Lfto gofo ogro fc ogfo'o szf'o zgfo gz ztto ootoo oofo zLfo fgg'o fg ogfo'o 9Lf0 90'0 90I*0 91 000'0 199'0 1190 91FLo fg ogfo'o Lets) 6gto 699'0 gz ootoo fggo goLo pro fg ogfo'o oofo LfSo £19'0 gz ooto'o ca° fLfo f6to gg oogo'o 91910 ggf'o 969'0 gz ootoo fLeo gtOo ggf'o gc oogo'o fgo 069'0 oLLo gz ootoo crt0 zzfo sfo 91 oogo'o gzf'o £91'0 Ltto 6z ogtoo oofo fLfo 169o gg oogo'o fLeo Lgto zzfo 6: ogtoo ggf'o ffiro ffLo gg oogo'o Leto t6to fLfo 6: ogtoo 919'0 ort °fro gr oogo'o odo gffo gtg'o 6z ogtoo f4o ftt'o f49o Lc otgo'o 10'0 6190 fOL'O 6z cute° hCto fzfo stfro 4s otgo'o fgg'o '49'o fLL0 6z ogtoo oof'o fLf'o foLo 48 otwo szf'o 01 191"o oft'o ottoo ggf'o hero f9Lo Lc otgo'o 94fo 6g1o fzf'o oc otto'o fgro fzLo ttgo Is otgo'o Lfto f6to 6L9'o oc ottoo 94fo gtOo tgfo gs fgpo oof'o of ogf'o 9109'0 oftoo Lfto tzfo sfcro gs fggo'o 199'0 S19'0 1,0LO oc ofto oofo fLfo sz4o gs fegoo Scrip f69'o 644'o 01 oftoo rgfo gego fLLo gs fogoo szfo fgfo tft'o zs fttoo feg'o tz4o zfgo gg fggoo f4fo zfto zg ogSo Sttoo SLt'o gtto 16o 68 fzio Lfto is 061'0 tgfo fttoo Lft'o gzf'o 659'0 68 fzioo oofol z9So ofgo zg fttoo ooto 449o ogLo 6s filioo ggf'o Ig fg90 gIL'O fttoo ggf'o otgo fg4o 68 fitoo Sggo 969.0 tg4o zg Stto Sggo tz4o Lgo 64 fzioo czto Lgeo zgto cc o4too 14o :fto togo of o94co S49o ftto 4g9o cc o4too 4Cto gzf'o (aro of o94o 4ftco L6to z69o cg oity'o oofo ogfo 804'o of ogPoo °of* fgS'o LS90 cc cato'o 1950 ftgo $64'o of 091AO ggfo fggo 6z4o cc o4two fgo LzPo 6go of ogkoo fgg'o 96911 g6Lo cc 0/to fLtv Ift'o Izo zf ozgoo

I Ob-S Chapter 15--THE REPAIR DEPARTMENT AND REPAIR WORK

Table 15-3.-Data for Winding Piano Wire Tension Springs-Continued

Dia=InsideOutside ,,,.... Dian'.InsideOutside of Dim.Diem. 01 Diem.Dian'. Man- of of ber ofof Pianoman. d of bee ofof Piano Piano Wire. Piano Wire, drel. *wing.Swing, v..y...h.. dill.spring.Spring.wininches InchesInchesInches --^-InchesInchesInches o.437o.322 o.684 31 o.o81 0.3730.48oo.682 34 0.101 0.300 0.383 0.747 31 0.081 0.4370.5500.752 34 0.101 o.362 0.647 0.809 31 o.olit o.3ooo.6zoo.8t2 34 o.to: o.623 o.722 0.884 31 o.olit o.362p.673u.873 34 0.101 0.373 0.461 0.633 32 o.o86 o.6230.7300t952 34 0.102 0.437 0.327 0.699 32 0.086 0.3730.490o.7o8 35 0.109 o.soo o.390 o.762 32 o.o86 o.437o.36oo.778 39 o.t69 0.562 o.6s1 0.823 32 o.o86 0.3000.6220.84o 39 0.109 o.623 0.727 0.899 32 o.o86 42.562o.6860.904 39 0.209 0.373 0.467 0.649 33 0.091 o.6230.7630.983 3s 42.109 0.437 0.533 0.713 33 0.091 0.3750.3000.736 36 oa18 0.300 0.395 0.777 33 0.092 0.4370.572o.8o8 36 oat8 o.562 0.637 0.839 33 0.091 0.3000.6370.873 36 oat8 o.623 0.733 0.915 33 0.091 o.5620.7020.938 36 o.1z8

plate. Make the groove the proper depth for the will have to follow local guidelines. In most size of wire from which the springs are being ships and at shore installations there is also a wound. Tighten this clamping arrangement with calibrationprogramwhere allmeasuring the toolpost wrench. Use just enough tension instrumentsareperiodicallycheckedfor onthewrenchtokeepthewirefrom accuracyagainststandards.Usually,this slipping. program is coordinated by the IM shop. Before using measuring tools from the toolroom, you as Further information and strengths of wire the machine operator, should check for an can be found in the Machinery's Handbook. up-to-datesticker affixedtothe measuring device, and then check the instrument against the standard usually kept in the toolroom. In most cases, upon completion of a manufactured part, the shop quality assurance inspector will QUALITY ASSURANCE check the part against the blueprint for accuracy and document the result on a Quality Assurance Form. On this form is recorded the name of the Qualityassuranceisaninspectionof ship,part manufacturer, print number used, manufactured parts to ensure that they meet serialnumber and calibrationdate of the blueprint specifications. Quality assurance is also instrument used to check the workpiece, the used to lay out procedures in assembling and name of the person who manufactured the part, disassemblingdifferentcomponents. Quality and the person who made the final quality assuranceshouldbeusedinallstepsof assuranceinspection.Todeterminetype manufacturing, such as checking diameters and commander quality assurance guidelines, your lengths, etc. Basic quality assurance guidelines shopleadingpettyofficershould beable are usually set by type commanders such as to find up-to-date information and have access SERVLANT, SUBLANT, SERVPAC, SUBPAC. totheappropriatedirectivesanddocu- Until itis coordinated under one system, you ments.

15-41 MACHINERY REPAIRMAN 3 & 2

CALIBRATION SERVICING over the entire range of the instrument. Only the LABELS AND TAGS needed quantities and ranges are calibrated. A SPECIAL CALIBRATION label(black and Standards require a sticker or equivalent yellow) is used to draw attention to the special certification, showing the date and place of conditionsunderwhichtheinstrumentis calibration, before they can be used to check calibrated. In addition to the label, a special operating instruments. Instruments calibrated by calibration tagis attached to the instrument. MIRCS require labels and tags to indicate the This tag is filled in by the servicing activity to status of calibration or testing. In marking labels adequately describe the conditions which are to and tags, MIRCS personnel should insert in the be observed in the use of the instrument. The DATE and DUE columnstheappropriate label and tag remain on the instrument until the month, day, and year, such as 8 Dec 1980. The next calibration. The 3-inch by 2-inch special Metrology Engineering Center's 3-letter code calibration label may be used alone in lieu of the designation of the servicing MIRCS is written or labelandtagcombination whenspaceis stamped on applicable labels and tags. The available on the instrument and reasons for various labels and tags for calibration standards special calibration can be shown on the label or test and measuring equipment within MIRCS itself. are shown in figures 15-35 and 15-36. Calibration Not RequiredNot Calibrated Used for Quantitative Measurement

Some instruments normally fall within the The CALIBRATED label is placed on each category of equipment requiring calibration, but standard or test and measuring equipment that are not used for quantitative measurements for has been checked against a standard of higher various reasons. With several like instruments, accuracy,usingapprovedNavycalibration for example, only one or two are calibrated and procedures and checklists, and adjusted to meet used for quantitative measurements; the others (1) a predeterminedspecification(manu- areusedasindicatorsonly.Also,some facturer'stolerance,orother)or(2)a instruments do not require calibration because specified value of magnitude and uncertainty. they receive an operational check each time they Thisspecifiedvalue may beexpressed for areused,ormalfunctionsand/orlossof single-value instruments, such as standard cells, accuracyarereadilyapparent duringtheir orformultivalueinstruments,suchas normaluse.Theseinstrumentscomprise potentiometers.Whenaninstrumentis components, such as amplifiers, junction boxes, calibratedtomeetapredeterminedspec- line transformers and line regulators. A label ification,onlytheknowledgethatthe (orange on white), indicating that calibration is instrument is within this specificationissig- not required because the instrument is not used nificant, and a black on white label is used. for quantitative measurements, is placed on the When an instrument is calibrated to maet an instrument. expressed value of magnitude and uncertainty, theactualmeasuredvalueandar'ociated Calibrated-In-Place uncertainty are reported, a red on white label is used, and a Report of Calibration is provided The CALIBRATED-IN-PLACE label is used with the instrument. by on-site calibration teams to identify items, suchasliquidometerindicators,thatare Special Calibration calibrated in place and should not be forwarded to the calibration laboratory. These labels (blue On occasion, specific user requirements do on white) alert the ships' forces that the items not involve the full instrument capability. In should not be off-loaded when ships come into such instances a calibration is not performed port.

15-42 #2 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

CALIBRATION NOT REQUIRED

NOT USED POR QUANTITATIVE MEASUREMENT NAVY CALIBP P.TION J PROGRAM (BLACK ON WHITE) (ORANGE ON WHITE)

CALIBRATED

NAVY NAVY fk--CALIBRATED CALIBRATION CALIBRATION NAVY PROORAM CP IBRATION PROGRAM PM NAM DATE. CALIBRATED DATE .. DUE (RED ON WHITE) (RED ON WHITE) (BLUE ON WHITE)

NAVY CALIBRATION PROGRAM CALIBRATED

(BLACK ON WHITE)

CALIBRATION VOID IF SEAL BROKEN (BLACK ON WHITE )

CALIBRATED NAVY' MULTIPLE INTERVAL CALIBRATION PARTIAL PROGRAM DUE DATE COMPLETE

DUE

DATE

(BLACK ON WHITE ) (GREEN ON WHITE)

1/3.6 Figure 15.35. Labels.

15-43 MACHINERY REPAIRMAN 3 & 2

SPECIAL REJECTED

CALIBRATION SERVICING ACTIVITY MANUFACTURER

SERVICING ACTIVITY MANUFACTURER DATE MODEL

DATE MODEL SUBMITTING ACTIVITYSERIAL

SUBMITTING ACTIVITY SERIAL REASON

REASON

USE REVERSE SIDE IF REQUIRED SUGGESTED CORRECTIVE ACTION 1

11011 REJECTE1 00111101100 AMR TO 101001100 ATTACHED TAG SPECIAL NAVY CALM= CALIBRATION _,I. 10 100 PROGRAM 0111

`DATE

USE REVERSE SIDE IF REQUIREL UE" REVERSE SIDE IF REQUIRED NAVMAT FORM NO. 4355 22 NAVMAT FORM NO 4355 23

(BLACK ON YELLOW', ( BLACK ON RED) 173.6A Figure 16-36.Libels and Tags.

Calibration Void If Seal Broken servicing activity giving the reason for rejection and other information as required. The rejected This label (black on white) is used to prevent label and tag remain on the instrument until it is tampering with certain adjustments which would repaired and reserviced. The instrument is not to affect the calibration. be used while bearing a rejected label.

Rejected Inactive

If an instrument fails to meet the acceptance The INACTIVE labelisplaced on an criteriaduringcalibrationandcannotbe instrument of the type which normally requires adequately serviced, a REJECTED label (black calibration and is found to have no foreseeable on red) is placed on the instrument and all other usage requirements. The inactive label remains servicing labels are removed. In addition to the on the instrument until itis reserviced. The REJECTED label, a REJECTED tag is placed on instrument is not to be used while bearing the the instrument. The tagisfilled in by the inactive label.

15-44 Chapter 15THE REPAIR DEPARTMENT AND REPAIR WORK

MRCS Labels on engines, boilers, and systems not used to test or calibrate other instruments. The labels\ Labels printed or procured locally are to may be printed using the MIRCS three-letter beused ongages,tachometers, and other code, with date and date due,as shown in figure normal work instruments, such as those used 1 5-35. APPENDIX I TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table 1-1.-Decimal Equivalents of Fractions (Inch) frac-St ..itt- # 44 St decimal frac-####'it decimal tions64ths32ds 1 6ths 8ths4ths equiv. tions64ths 32cs l6ths 8ths 4ths equiv.

1/64 1 0.015625 33/64 33 0.515625 1/31 2 1 0.03125 0/32 34 17 0.53125

3/64 3 0.046875 3%4 35 0.546875

3/16 4 2 1 0.0625 /16 36 18 9 0.5625

5/64 5 0.078125 31/44 37 0.578125 3/32 6 3 0.09375 39/32 38 19 0.59375

1/44 7 0.109375 39/64 39 0.609375 1/8 8 4 2 1 0.125 Ye 40 20 10 5 0.625

9/64 9 0.140625 43/64 41 0.640625 'Az 10 5 0.15625 21/32 42 21 0.65625

3%4 11 0.171875 43/64 43 0.671875

3A 6 12 6 3 0.1875 1116 44 22 11 0.6875

13/64 13 0.203125 4%4 45 0.703125 7/32 14 7 0.21875 23/32 46 23 0.71875

35/64 15 0.234375 4%4 47 0.734375

V4 16 8 4 2 1 0.250 34 48 24 12 6 3 0.750

17 11/44 0.265625 4%4 49 0.765625

9/32 18 9 0.28125 25/32 50 25 0.78125

1944 19 0.296875 53/64 51 0.796875

5/), 20 10 5 0.3125 13/16 52 26 13 0.8125

21/44 21 0.328125 53/64 53 0.828125 33/32 22 11 0.34375 2132 54 27 0.84375

23A4 23 0.359375 '5/64 55 0.859375

Ye 24 12 6 3 0.375 Ys 56 28 14 7 0.875

25A4 25 0.390625 5%4 57 0.890625 13/32 26 13 0.40625 29/32 58 29 0.90625

27/64 27 0.421875 59/64 59 0.921875

'/16 28 14 7 0.4375 01/26 60 30 15 0.9375

29/64 29 0.453125 61/64 61 0.953125 35/32 30 15 0.46875 31/32 62 31 0 4.96875 3%4 31 0.484375 0%4 63 0.984375

1/2 32 16 8 4 2 0.500 1 inch 64 32 16 8 4 1.000

AI-1 r Liu)1' MACHINERY REPAIRMAN 3 & 2

Table I-2.-Decimal Equivalents of Millimeters mm inches mm inches mm inches rr rn inches mm inches

0.1 0.00394 3.5 0.13779 6.9 0.27165 10.3 0.40551 13.8 0.54330 0.2 0.00787 3.6 0.14173 7.0 0.27559 10.4 0.40944 13.9 0.54124 0.3 0.01181 3.7 0.14566 7.1 0.27952 10.5 0.41388 14.0 0.55118 0.4 0.01575 3.8 0.14960 7.2 0.28346 10.6 0.41732 14.1 0.55511

0.5 U 91968 3.9 0.15354 7.3 0.28740 10.7 0.42125 14.2 0.55905 0.6 0.02362 4.0 0.15748 1.4 0.29133 10.8 0.42519 14.3 0.56299 0.7 0.02156 4.1 0.16141 7.5 0.29527 10.9 0.42913 14.4 0.56692 0.8 0.03149 4.2 0.16535 7.6 0.29921 11.0 0.43307 14.5 0.57086

0.9 0.03543 4.. 0.16929 7.7 0.30314 11.1 0.43700 14.6 0.57480

1.0 0.03937 4.4 0.17322 1.8 - 0.30108 11.2 0.44094 14.7 0.57813 1.1 0.04330 4.5 0.17716 1.9 0.31102 11.3 0.44488 14.8 0.58261 1.2 0.04124 4.6 0.18110 P 0 0.31496 11.4 0.44881 14.9 0.58661

1.3 0.05118 4.7 0.18503 8.1 0.31889 11.5 0.45215 15.0 0.59055 1.4 0.05512 4.8 0.18891 8.2 0.32283 11.6 0.45669 15.5 0.61023 1.5 0.05905 4.9 0.19291 8.3 0.32677 11.1 0.46062 16.0 0.62992 1.6 0.06299 5.0 0.19685 8.4 0.33070 11.8 0.46456 16.5 0.64960

1.7 0.06692 5.1 0.20018 8.5 0.33464 11.9 0.46850 17.0 0.66929 1.8 0.07086 5.2 0.20472 8.6 0.33858 12.0 0.47244 17.5 0.68897 1.9 0.01480 5.3 0.20866 8.1 0.34251 12.1 0.47631 18.0 0.70866 2.0 0.07874 5.4 0.21259 8.8 0.34645 12.2 0.48031 18.5 0.72834

2.1 0.08267 5.5 0.21653 8.9 0.35039 12.3 0.48425 19.0 0.74803 2.2 0.08661 5.6 0.22041 9.0 0.36433 12.4 0.48818 19.5 0.76771 2.3 0.09055 5.7 0.22440 9.1 0.35826 12.5 0.49212 20.0 0.78740 2.4 0.09448 5.8 0.22834 9.2 0.36220 12.6 0.49606 20.5 0.80708

2.5 0.09842 5.9 0.23228 9.3 0.36614 12.7 0.49999 21.0 0.82677 2.6 0.10236 6.0 0.23622 9.4 0.31007 12.8 0.50393 21.5 0.84645 2.1 0.10629 6.1 0.24015 9.5 0.31401 12.9 0.50187 22.0 0.86614 2.8 0.11023 6.2 0.24409 9.6 0.37795 13.0 0.51181 22.5 0.88582

2.9 0.11417 6.3 0.24803 9.7 0.38188 13.1 0.51574 23.0 0.90551 3.0 0.11811 6.4 0.25196 9.8 0.38582 13.2 0.51968 23.5 0.92519 3.1 0.12204 6.5 0.25590 9.9 0.38976 13.3 0.52362 24.0 0.94488 3.2 0.12598 6.6 0.25984 10.0 0.39370 13.4 0.52155 24.5 0.96456 13.5 0.53149 25.0 0.98425 3.3 0.12992 6.7 0.26377 10.1 0.39163 13.6 0.53543 25.5 1.00393 3.4 0.13385 6.8 0.26771 10.2 0.40157 13.7 0.53936 26.0 1.02362

AI-2 I? Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-3.-Dividing a Circle into Parts

To find the length of the chord for dividing the circumference ofa circle into a required number of equal parts, multiply the LA:tor in the table by the diameter.

no. of chord no. of chord no. of chord spaces length spaces length spaces length

3 0.866 21 0.149 39 0.0805 4 0.7071 22 0.1423 40 0.0785 5 0.5878 23 0.1362 41 0.0765 6 0.5 24 0.1305 . 42 0.0747 7 0.4339 25 0.1253 43 0.073 8 0.3827 26 0.1205 44 0.0713 9 0.342 27 0.1161 45 0.0698 10 0.309 28 0.112 46 0.0682 11 0.2818 29 0.1081 47 0.0668 12 0.2584 30 0.1045 48 0.0654 13 0.2393 31 0.1012 49 0.0641 14 0.2224 32 0.098 50 0.0628 15 0.2079 33 0.0951 51 0.0616 16 0.1951 34 0.0932 52 0.0604 17 0.1837 35 0.0896 53 0.0592 18 0.1736 36 0.0872 54 0.0581 19 0.1645 37 0.0848 55 0.0571 20 0.1564 38 0.0826 .

AI-3533 MACHINERY REPAIRMAN 3 & 2

Table 1.4. Formulas for Dimension, Area, end Volume

1/1 ALT ALT W WIDTH BASE X 11547 W MVP 1/BASEI ALTS Y 1 4142 W BASE fNYP= - ALT2 Z 10824 W ALTVI+TP2 - BASE' DIA BASE ALT - myP

.--- BASE BASE BASE BASE RAD ALT COT A - COT B COT + COT,

PERIMETER BASE ALT R BASE x ALT R PERIMETER

12 L

fi 0

0. D -

1 * 0 OR L 12 r 12 1 D - o TAN,. r - 2 L X 5 SINE OF 4

0 PLUG SIZE TAN .1 -5 r TAPER PER FT

TAN 4 Y (.; CEC.1A).;

T 2IL TAN 4.1 2 2 COT .1A o0 -r 2 90 X Y - I = X COT .- 2 2 A INCLUDED 4 P PLUG SIZE X P 2, X 5 SIN INC 4 Y x 15 2

AI-4 . (-) Appendix ITABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table 1.4.Formulas for Dimension, Area, and VolumeContinued

TRIANGLE TRAPEZOID CIRCLE [6 B

B B

AREA .4- BXA AREAi (A +B)H AREA. 3.1416 At

FILLET SEGMENT RECTANGULAR PRISM

ARt 3 14I5RI 4 2H VOLUME ABC

TRIANGULAR PYRAMID FRUSTUM OF PYRAMID SPHERE

D. 2 RNs AREA OF BASE X H Hf A +B+/^.0 VOLUME VOLUME 3 3 VOLUME 4X3.1416R3 3

CYLINDER CONE FRUSTUM OF CONE

VOLUME. 3 1415 RI X H VOLUME. 31416RI X H VOL02618H(Ol+DI +DO 3

AI-5 5u MACHINERY REPAIRMAN 3 & 2 .1)

Table I-5.Formulas for Cirdes

Circumference of a circle = Diameter multiplied by 3.1416 = Diameter divided by 0.3183 Diamet r o a circle = Circumference multiplied by 0.3183 = Circumference divided by 3.1416 Side of a square inscribed in a given circle = Diameter multiplied by 0.7071 = Circumference ,nultiplied by 0.2251 = Circumference divided by 4.4428 Side of a square with area of a given circle = Diameter multiplied by 0.8862 = Diameter divided by 1.1284 = r'ircumference multiplied by 0.2821 rcumference divided by 3.545 Diameter of a circle with area of a given square = Side multiplied by 1.128 Diameter of a ci:cle circumscribing a given square = Side multiplied by 1.4142 Area of a circle = The square cf the diameter multiplied by 0.7854 = The square of the radius multiplied by 3.1416 Area of the surface of a sphere or globe = The square of the diameter multiplied by 3.1416 Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-6.-Number, Letter and Fractional Identification of Drill Sizes (Letter drillsare larger than number drills; they begin where number drills end.)

no.& fiat- dec- no.& frac- dec- no.& frac- dec- no.& frac- dec- lettertional imal letter tional imal letter tional imal lettertionalimal drills drills equiv. drills drills equiv. drills drills equiv. drills drillsequiv.

80 ... .0135 42 ... .0935 13;4 .2031 13 2 .4062 79 ... .0145 '32 .0937 6 ... .2040 Z ... .4130 1/44 .0156 41 .. .0960 5 ... .2055 '27,4;4 .4219 78 ... .0160 40 ... .0980 4 ... .2090 7/1 6 .4375 77 .... .0180 ... 39 .0995 3 ... .2130 -1,164 .4531 76 ... .0200 .38 ... .1015 72 .2187 1 % 2.4687 75 .. . .0210 37 ... .1040 2 ... .2210 3 1/6 4 .4844 74 ... .0225 36 ... .1065 1 ... .2280 1/_ .50005000 73 ... .0240 7, G4 .1094 A . .. .2340 72 ... .0250 35 ... .1100 1 r;,64 .2344 3 % 4 .5156

71 ... .0260 34 ... .1110 B ... .2380 1%2 .5312

70 ... .0280 33 ... .1130 C ... .2420 3 % 4 .5469

69 ... .0292 32 ... .1160 D ... .2460 %6 .5625

...... 68 .0310 31 .1200 E 1/4 .2500 3 6 4 .5781 1/32 .0312 1/8 .1250 F ... .2570 1% 2 .5937 67 ... .0320 30 ... .1285 G ... .2610 3 % 4 .6094 66 ... .0330 29 ... .1360 1%4 .2656 % .6250 65 ... .0350 28 ... .1405 H ... .2660 4 Y64 .6406 64 ... .0360 %4 .1406 I ... .2720 2 lA .6562 63 ... .0370 27 .... .1440 J ... .2770 4 %4 . 62 ... .0380 26 ... .1470 K ... .2810 1%6 .6875 61 ... .0390 25 ... .1495 %2 .2812 4 %4 .7031 60 ... .0400 24 ... .1520 L ... .2900 2%2 .7187 ... 59 .0410 23 ... .1540 M ... .2950 4% .7344 58 ... .0420 % 2 .1562 1%4 .2969 % .7500 57 ... .0430 22 . .. .1570 N . .. .3020 56 ... .0465 21 ... .1590 5/ 6 .3125 4 %4 .7656 %4 .0469 20 ... .1610 0 ... .3160 2%2 .7812 55 ... .0520 19 ... .1660 P . .. .3230 51/c4 .7969 .. .3281 54 . .0550 18 ... .1695 21/64 13/16 .8125 53 ... .0595 11/44 .1719 ... Q .3320 5%4 .8281 1/16 .0625 17 ... .1720 R ... .3390 2% .8437 52 ... .0635 16 . .. .1770 11/32 .3437 5%4 8594 51 .. .0670 15 ... .1800 S ... .3480 74 .8750 50 ... .0700 14 ... .1820 T ... .3580 49 ... .0730 13 ... .1850 2%4 .3594 57/64 .89'J6 2%2 .9062 48 ... .0760 % 6 .1875 U ... .3880 %4 .0781 12 . .. .1890 % .3750 5%4 9219 . 47 .. .0785 11 ... .1910 V ... .3770 15/1 6 .9375 6 1/64 46 .0810 10 ... .1935 W ... .3860 .9531 45 ... .0820 9 ... .1960 2% .3906 31/2 .9687 44 ... .0860 8 ... .1990 X ... .3970 6%4 .9844 43 ... .0890 7 .. .2010 Y . .. .4040 , 1 1.0000

AI-7 3 & 2 07111.04110111INMB 1101 00

Table I-7.Units of Weight, Volume, and Temperature

AVOIRDUPOIS WEIGHT SQUARE MEASURE 16 drams or 437.5 grains = 1 ounce 144 square inches = 1 square foot 16 ounces or 7,000 grains = 1 pound 9 square feet = 1 square yard 2,000 pounds = 1 net or short ton 30.25 square yards = 'I square rod 2,240 pounds = 1 gross or long ton 160 square rods = 1 acre 2,204.6 pounds = 1 metric ton 640 acres = 1 square mile BOARD MEASURE TEMPERATURE One board foot measure is a piece of wood 12 Freezing, Fahrenheit scale = 32 degrees inches square by 1 inch thick, or 144 cubic inches. Freezing, celcius scale = 0 degrees A piece of wood 2 by 4, 12 feet long contains 8 feet Boiling, Fahrenheit scale = 212 degrees board measure. Boiling,celcius scale = 100 degrees DRY MEASURE If any degree on thecelcius scale, either 2 pints = 1 quart above or below zero, be multiplied by 1.8, the result 8 quarts = 1 peck will, in either case, be the number of degrees above 4 pecks = 1 bushel or below 32 degrees Fahrenheit. 1 standard U.S. bushel = 1.2445 cubic feet TROY WEIGHT 1 British imperial bushel = 1.2837 cubic feet 24 grains = 1 pennyweight LIQUID MEASURE 20 pennyweights = 1 ounce

4 gills = 1 pint . 12 ounces = 1 pound 2 pints = 1 quart WEIGHT OF WATER 4 quarts = 1 gallon 1 cubic centimeter = 1 gram or 0.035 ounce 1 U.S. gallon = 231 cubic inches 1 cubic inch = 0.5787 ounce 1 British imperial gallon = 1.2 U.S. gallons 1 cubic foot = 62.48 pounds 7.48 U.S. gallons = 1 cubic foot 1 U.S. gallon = 8.355 pounds LONG MEASURE 1 British imperial gallon = 10 pounds 12 inches = 1 foot 32 cubic feet = 1 net ton (2,000 pounds) 3 feet = 1 yard 35.84 cubic feet = 1 long ton (2,240 pounds) 1,760 yards = 1 mile 1 net ton = 240 U.S. gallons 5,280 feet = 1 mile 1 long ton = 268 U.S. gallons 16.5 feet = 1 rod ENGLISH-METRIC EQUIVALENTS PAPER MEASURE 1 inch = 2.54 centimeters 24 sheets = 1 quire 1 centimeter = 0.3937 inch 20 quires = 1 ream 1 meter = 39.37 inches 2 reams = 1 bundle 1 kilometer = 0.62 mile 5 bundles = 1 bale 1 quart = 0.946 liter SHIPPING MEASURE 1 U.S. gallon = 3.785 liters 1 U.S. shipping ton = 40 cubic feet 1 British gallon = 4.543 liters 1 U.S. shipping ton = 32.143 U.S. bushels 1 liter = 1.06 quarts 1 U.S. shipping ton = 31.16 imperial bushels 1 pound = 0.454 kilogram 1 British shipping ton = 42 cubic feet 1 kilogram = 2.20 pounds 1 British shipping ton = 33.75 U.S. bushels 1 watt = 44.14 foot-pounds per minute 1 British shipping ton = 32.718 imperial bushels 1 horsepower = 33,000 foot-pounds per minute 1 kilowatt = 1.34 horsepower

AI-8

5 543 Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERYREPAIRMAN

Table I 8.-Screw Thread and Tap Drill Sizes (American National) threads tap drill per inch dimensions, inches 75% full thread NC NF single screw coats? fine major pitch depth of minor tap decimal bodydecimal size thread thrz:.td diameter diameter thread diameter drill equiv. drill equiv. 0 80 0.060 J.0519 0.00812 0.0438 3/64 0.0469 52 0.0635 1 64 0.073 0.0629 0.01015 0.0527 53 0.0595 47 0.0185 1 72 0.073 0.0640 0.00902 0.0550 53 0.0595 47 0.0785 2 56 0.086 0.0744 0.011;0 0.0628 50 0.0700 42 0.0935 2 64 0.086 0.0759 0.01015 0.0651 50 0.0700 42 0.0935 3 48 0.099 0.0855 0.01353 0.0719 47 0.0785 37 0.1040 3 56 0.099 0.0874 0.01160 0.0758 45 0.0820 37 0.1040 4 40 0.112 0.0958 0.01624 0.0795 43 0.0890 31 0.1200 4 48 0.112 0.0985 0.01353 0.0849 42 0.0935 31 0.1200

5 40 0.125 0.1088 0.01624 0.0925 38 0.1015 29 0.1360 5 44 0.125 0.1102 0.01416 0.0955 37 0.1040 29 0.1360 6 32 0.138 0.1177 0.02030 0.0974 36 0.1065 27 0.1440 6 40 0.138 0.1218 0.01624 0.1055 33 0.1130 27 0.1440 8 32 0.164 0.1431 0.02030 0.1234 29 0.1360 18 0.1695 8 36 0.164 0.1460 0.01804 0.1279 29 0.1360 18 0.1695 10 24 0.190 0.1629 0.02706 0.1359 25 0.1495 9 0.1960 10 32 0.190 0.1697 0.02030 0.1494 21 0.1590 9 110.1960 24 12 0.216 0.1889 0.02706 0.1619 16 0.1770 2 0.2210 12 28 0.216 0.1928 0.02320 0.1696 14 0.1820 2 0.2210

1/4 20 0.2500 0.2175 0.03248 0.1850 7 0.2010 1/4 28 0.2500 0.2268 0.02320 0.2036 3 0.2130 5/16 18 0.3125 0.2764 0.03608 0.2403 F 0.2570 5/is 24 0.3125 0.2854 0.02706 0.2584 I 0.2720 % 16 0.3750 0.3344 0.04059 0.2938 3/16 0.3125 3/ 24 0.3150 0.3479 0.02706 0.3209 0 0.3320 7/16 14 0.4375 0.3911 0.04639 0.3441 U 0.3680

1/16 20 0.4375 0.4050 0.03248 0.3725 25/64 0.3906 V2 13 0.5000 0.4500 0.04996 0.4001 21/64 0 4212

1/2 20 0.5000 0.4675 0.03248 0.4350 29/64 0.4531

9.46 12 0.5625 0.5084 0.05413 0.4542 344 0.4844

3/16 18 0.5625 0.5264 0.03608 0.4903 31/44 0.5156 % 11 0.6250 0.5660 0.05905 0.5069 17/32 0.5313 5/8 18 0.6250 0.5889 0.03608 0.5528 31/64 0.5781 % 10 0.1500 0.6850 0.06495 0.6201 21/42 0.6562 y4 16 0.7500 0.7094 0.04059 0.6688 II/16 0.6875

7/4 9 0.8750 0.8028 0.07217 0.7307 49/64 0.1656 N 14 0.8750 0.8286 0.04639 0.7822 '346 0.11125

1 8 1.0000 0.9188 0.08119 0.8376 Ye 0.8750 1 14 1.0000 0.9536 0.04639 0.9012 15 /i6 0.9375 11/4 7 1.1250 1.0322 0.09279 0.9394 67/64 0.9844 11/4 12 1.1250 1.0709 0.05413 1.0167 1%4 1.0469 11/4 7 1.2500 1.1572 0.09279 1.0644 V/64 1.1094

11/4 12 1.2500 1.1959 0.05413 1.1411 111/44 1.1719 11/4 6 1.3750 1.2667 0.10825 1.1585 1'/32 1.2188 1% 12 1.3750 1.3209 0.05413 1.2667 11%4 1.2969 11/4 6 1.5000 1.3917 0.10825 1.2835 111/22 1.3438 11/4 12 1.5000 1.4459 0.05413 1.3917 121/44 1.4219 1% 5 1.7500 1.6201 0.12990 1.4902 14/I6 1.5625

2 41/4 2.0000 11557 0.14434 1.7113 125/32 1.1813 AI-9 574 MACHINERY REPAIRMAN 3 & 2

Table I-9.-Full Thread Produced in Tepoed Holes (Percentage)

tap decimal usual thread tat, decimal usual thread tap drill . tap drill hole size percentage tap drill tap drill hole size percentage

81-80 56 0.0465 0.0480 14 9.1065 0.1088 55 % 0.0469 0.0484 11 6-32 31 0.1040 0.1063 18 1.64 54 0.0550 0.0565 31 36 0.1065 0.1091 11

53 0.0595 0.0610 59 7/64 0.1094 0.1120 64 35 0.1100 0.1126 63 1.72 53 0.0595 0.0610 61 34 0.1110 0.1136 60

1/16 0.0625 0.0640 50 33 0.1130 0.1156 55

2.54 51 0.0610 0.0681 14 6-40 34 0.1110 0.1136 15 50 0.0100 0.0111 62 33 0.1130 0.1156 69 49 0.0130 0.0141 49 32 0.1160 0.1186 60

2-64 50 0.0100 0.0111 10 8-32 29 0.1360 0.1389 62 49 0.0130 0.0141 56 28 0.1405 0.1434 51

3.48 48 0.0160 0.0119 78 8.36 29 0.1360 0.1389 10 544 0.0181 0.0800 10 28 0.1405 0.1434 51 41 0.0185 0.0804 69 %4 0.1406 0.1435 51 46 0.0810 0.0829 60 45 0.0820 0.0839 56 10-24 21 0.1440 0.1412 19 26 0.1410 0.1502 14 3-58 48 0.0810 0.0829 69 25 0.1495 0.1521 69 45 0.0820 0.0839 65 24 0.1520 0.1552 64 44 0.0860 0.0819 48 23 0.1540 0.1512 61

5/32 0.1563 0.1595 56 4 -40. 44 0.0860 0.0880 14 22 0.1570 0.1602 55 43 0.0890 0.0910 65 42 0.0935 0.0955 51 10.32 542 0.1563 0.1595 15 142 0.0938 0.0951. 50 22 0.1570 0.1602 13 21 0.1590 0.1622 68 4.41 42 0.0935 0.0955 61 20 0.1610 0.1642 64 142 0.0938 0.0958 60 19 0.1660 0.1692 51 41 0.0960 0.0980 52 12-24 11/64 0.1719 0.1154 15 5.40 40 0.0980 0.1003 16 11 0.1130 0.1165 13 39 0.0995 0.1018 11 16 0.1110 0.1805 66 38 0.1015 0.1038 65 15 0.1800 0.1835 60 31 0.1040 0.1063 58 14 0.1820 0.1855 56

5.44 38 0.1015 0.1038 12 12 -28 16 0.1110 0.1805 11 31 0.1040 0.1063 63 15 0.1800 0.1835 10 Appendix I -TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-9.-Full Thread Produced in Tapped Holes (Percentagel-Continued

top decimal usual thread top decimal usual thread lap drill tap drill hole size percentage top drill top drill hole size percentage

12-28 14 0.1820 0.1855 66 1/2 -13 27/64 0.4219 0.4266 73 13 0.1850 0.1885 59 Vis 0.4375 0.4422 58 Ms 0.1875 0.1910 54 1/2 -20 Ns 0.4531 0.4578 65 'A -20 9 0.1960 0.1998 77

8 0.1990 0.2028 73 9/16-12 1%2 0.4688 0.4736 82

7 0.2010 0.2048 70 31/64 0.4844 0.4892 68 Iy64 0.2031 0.2069 66 6 0.2040 0.2078 65 9/1 1 8 1/2 0.5000 0.5048 80

5 0.2055 0.2093 63 33/44 0.5156 0.5204 58 4 0.2090 0.2128 57 %-11 1%2 0.5313 0.5362 75 1/4 -28 3 0.2130 0.2168 72 3%4 0.5469 0.5518 62 2A2 0.2188 0.2226 59 2 0.2210 0.2248 55 % -18 Ms 0.5625 0.5674 80 37/4 0.5781 0.5831 58 M6-18 F 0.2570 0.2608 72

G 0.2610 0.2651 66 3/4 -10 41/44 0.6406 0.6456 80 17/64 0.2656 0.269 i 59 21/32 0.6563 0.6613 68 H 0.2660 0.2701 59

3/ -16 I1/16 0.6875 0.6925 71 %6-24 H 0.2660 0.2701 78 I 0.2720 0.2761 67 %-9 4%4 0.7656 0.7708 72 I 0.2770 0.2811 58 2%2 0.7812 0.7864 61

% -16 %6 0.3125 0.3169 72 %-1 4 5%4 0.7969 0.8021 19 0 0.3160 0.3204 68 'Ms 0.8125 0.8117 62 P 0.3230 0.3274 59

1-8 55/64 0.8594 0.8653 83 21/64 %-24 0.3281 0.3325 79 % 0.8750 0.8809 13

Q 0.3320 0.3364 11 57/64 0.8906 0.8965 64

R 0.3390 0.3434 58 29/32 0.9063 0.9122 54

7/16-14 T 0.3580 0.3626 81 1.12 25/32 0.9063 0.9123 81 2%4 0.3594 0.3640 19 W64 0.9219 0.9219 61

U 0.3680 0.3126 , 15/16 0.9375 0.9435 52 % 0.3750 0.3796 6i V 0.3770 0.3816 60 1-14 5%4 0.9219 0.9219 78 1%6 0.9375 0.9435 81 Vi6 -20 W 0.3860 0.3906 72 25/n 0.3906 0.3952 85 X 0.3970 0.4016 55

Al-1 I MACHINERY REPAIRMAN 3 & 2

Table 1-10.-American National Pipe Thread Li Length of effective thread F itch diameter of thread of end of pipe Ineffectivethread BPitch diameter of thread at gouging notch Engagement 's 111N D 2 Outside diameter of pipe 124 Normal engagement by hand between D Taper 3/4 in. per foot eat I and Internal thread on diameter =MIz.V/7/74',

Tap Dab fee Pipe Three& Nib Disaster 18110 INN Os, 4 Direeds 0.0. el 044. Use Per 0 larewd Oleeweer Ilse Wee kids A I u 1.1 bode' ladles leis/ led OM Wee Wee 1A.Aes Wks* if PIP9 4 27 .36351 .37476 .2639 .180 .405 .02963 .3339 R 14 18 .47739 .48989 .4018 .200 .340 .04444 .4329 3S4 % 18 .61201 .62701 .4078 .240 .675 .04444 .5676 as, 1 14 .75843 .77843 .5337 .326 .840 .05714 .7013 3/4 % 14 .96768 .98887 .5457 .339 1.050 .05714 .9105 ilia

1 11% 1.21343 1.23863 .6828 .400 1.315 .06957 1.1441 13h 1% 11% 1.55713 1.58338 .7068 .420 1.660 .06957 1.4876 11/2 1% 111/2 1.79609 1.82234 .7235 .420 1.900 .06957 1.7265 141Ia 2 111/2 2.26902 2.29627 .7565 .436 2.375 .06957 2.1995 2Ps 2% 8 2.71953 2.76216 1.1375 .682 2.875 .10000 2.6195 2% 3 8 3.34062 3.38850 1.2000 .766 3.500 .10000 3.240d 3% 3% 8 3.83750 3.88881 1.2500 .821 4.000 .10000 3.7375 334 4 8 4.33438 4.38712 1.3000 .844 4.500 .10000 4.2344 4% Table 1-11.-3 Wire Method-American National Std.

M = D - (1.6156 X P) X W) D PD = -- 3- - (3 X W) No. of thds. per inch -M. To Check Angle W, - W.

61 = Measurerr,ent over best size wire. PD M. = Measurement over maximum size wire M. = Measurement over minimum size wire D = Outside Diameter of Thread. P.D. = Pitch Diameter. W = Diameter Best size wire. 0.57735 X pitch W, = Diameter maximum size wire. 0.90 x pitch. W. = Diameter minimum size wire. 0.58 x pitch

No. Thds. Pitch Best Wire Size MaximumMinimum per inchThds. per inch.57735 x Pitch Wire SizeWire Size 4 .250000 .144337 .226000 .140000 41/2 222222 .128300 .200000 .124444 5 .200000 .116470 .180000 .112000 5'/a .181818 .104969 .163636 .101818 6 .188888 .096224 .149999 .093333 7 .142857 .082478 .128571 .080000 7'4 '33333 .078979 .120000 .074666 14 .125000 .072168 .112600 .070000 9 .111111 .084149 .100000 .062222 10 .100000 .067736 .090000 .056000 II .093999 .05°459 .081818 .050909 11'4 .088968 .050204 .078280 .048695 12 .083333 .048112 .075000 .046666 1:1 .078923 .044411 .069231 .043077 14 .071426 .041239 .084285 .040000 In .062500 .035084 .066250 .036000 18 .055565 .032074 .060000 .Z2,11I 20 .050000 .028867 .046000 .028000 22 .043454 .026242 .040909 .025454 24 .041666 .024055 .037499 .023333 6 .038461 .022206 .034615 .021538 27 .037037 .021383 .033333 .022543 28 .035711 .020820 .032143 .020000 30 .033333 .019244 .030000 .018666 32 .031250 .018042 028125 .017600 38 .027777 .018037 .024999 .015555 JO .025000 .014433 .022600 .014000 41 .022727 .013121 .020454 .014727 48 .020833 .012027 .018750 .011666 50 .020000 .011647 .018000 .011200 56 .017857 .010309 .018071 .010000 61 .015621 .009021 .014083 .008750 72 013888 .00E1018 .012499 .007777 140 0125011 .007216 .011260 .007090

AI-12 0 i 7 Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-12.-Diagonals of Squares and Hexagons

E- 1.4142 d 1.1547 d

d D E d D E d D I

ri0.21960.3535 1.44341.76772 g 2.67043.2703 3 0.32470.3977 1 3 1.47941.81192 2.74243.3587 4 0.36080.441 1 iv1.51551.85612 14 2.81453.4471

its 0.39680.4861111 y 1155161.9003 2.98673.5355 0.43890.5303 1 1.58771.94452 14 2.95833.6239 3 0.46900.5745 1 31.62381.911872 A 3.03113.7123

7 0.50510.6117.17 1.65982.0329 3.10323.1007 3 0.54120/62 1 21.69592.0771214 3.17543.81191 0.5773O.'71 1 1.73202.12132 3/14 3.247 3.9794

1364 0.61330.751311;iig1.76112.16552% 3.31974.0658 1 4 0.64940.795513 41.80422.209721%4 3.391 4.1542 1As 0.3155Q.1397 1 ,441.84032.25393 3.46414.2426 % 0.72160.883 1% 1.87642.2981 3.53624.3310 1144 0.75760.91181131/441.912 2.34233 3.60844.4194 1 4 0.79370.972311%61.94852.3165334, 7.68' 4.5078 Ii4 0.82981.01 1371,1.91462.4306 3.75274.5962 0.86591. 114 2.02072.47087144 3.82494.6846 I0.90201.104811/422.05682.51903 3.89714.7729 "4, 0.93801.14 111/162.09292.563231/ 3.96924.8613 37 3 0.97411.193213%42.12892.60743 4.04144.9497 74 1.01021.237 1% 2.16502.65163 HI 4.11365.0381

11p4 1.04631.281 2.20112.69583% 4.18575.1265 1 14 1.08241.325811 4123722.740031%4 4.25795.2149 1 ha1.11841.37 13 3 2.27332.784233/4 4.33015.3033

1 1.15471.414!2 2.30942.828431%4 4.40235.3917 1%4 1.19071.458 2%42.34532.87263% 4.47445.4801 11/14 1.22681.502 NI2.38152.9168331/14 4.54665.5684

1 t 1.26291.5468 2.41762.96104 4.61885.6568 1 1.29901.591 2 2.45373.005241/4 4.76315.8336 1 4 1.33511.63522 3 2.48983.04944% 4.90746.0104 1%4 1.37121.679323A4 2.525J.09364% 5.05186.1872 1%3 1.40731.72352% 2.5981118204% 5.19616.3639 MACHINERY REPAIRMAN 3 & 2

Table I-13.-Circles Circumference of a circle - diameter X 3.1416 When doubled, the diameter of a pipe increases Diameter of a circle - circumference X .31831 capacity four times Area of a circle - the square of the diameter X .7854 Radius of a circle X 6.283185 - circumference Surface of aball(sphere) - the square of the Square of the circumference of a circle X .07958 diameter X 3.1416' area Side of a square inscribed in a circle - diameter X 1/2 circumference of a circle X 1/2 its diameter .70711 area Diameter of a circle to circumscribe a square - one Circumference of a circle X .159155 - radius side X 1.4142 Square root of the area of a circle X .56419 - radi Cubic inches (volume) in a ball cube of the Square root of the area of a circle X 1.1283e diameter X .5236 diameter

Table 1.14.- Keyway Dimensions

Woodruff keyways* shaft square dia keyways key thickness cutter dia slot depth

0.500 1/4X 1/5 404 0.1250 0.500 0.1405 0.562 1/4X Me 404 0.1250 0.500 0.1405 0.625 Y32 X 5Ag 505 0.1562 0.625 0.1669 0.688 3A6 X 342 606 0.1875 0.750 0.2193

0.750 346 X %2 606 0.1875 0.750 0.2193 0.812 3A6 x3 /32 606 0.1875 0.750 0.2193 0.875 x'/64 607 0.1875 0.875 0.2763 0.938 1/4 x Ye 807 0.2500 0.875 0.2500

1.000 Y4 X Ye 808 0.2500 1.090 0.3130 1.125 5/16 x M2 1009 0.3125 1.125 0.3228 1.250 5/16 X 5/32 1010 0.3125 1.250 0.3858 1.375 Ye x Mg 1210 0.3750 1.250 0.3595

1.500 Ye x Me 1212 0.3750 1.500 0.4535 1.625 Ye x Mg 1212 0.3750 1.500 0.4535 1.150 1/ie x1/32 1.875 1/2 X 1/1

1/2 2.000 1/4 2.250 Ye xY16 2.500 X 5/15 2.75^ y4 X %

3.000 3/4 X % 3.250 Ye X /8 3.500 //s x ' /16 4.000 1 X 1/4

'The depth of a Woodruff keyway Is measured horn the edge of the slot,

AI-14 t-4 t).) Teble I.15, -Tepee Per Foot end CoffemondIng Angles

angle with taper included angle with included angle velll taper included taper center line angle center line angle center line angle per per per min.sec, mittset deg, min, sec, foot deg,min,sec, deg, fool deg,min,sec. deg,min, sec,foot deg.

11 52 50 11 4 3% 11 15 I 2 II NA, 1 31 10 144 0 1 21 31 1 11 11 23 9 3% II 13 4 11 1 1 11 11 Vu I 1 9 21 1 11 11 11 32 8 1 11 9 SI 1 51 1%1 5 1 1)11 0 11 1% 11 30 II 9 15 1 11 I% 5 21 11 41 52 Ily 0 21 52 13 2 31 54 1 11 4% 20 S 2 10 11 54 1%, 5 39 1 0 15 If

39 11 10 11 II V S 54 1% 11 Ily 0 41 ii 21 12 1% S 11 31 I 31 49 4% 21 14 1 21 II 1%1 1 15 %1 0 53 4 51 11 I 13 1% 21 4 51 10 11 I% 1 9 11 /k I 2 31 31 I% 11 23 11 II 11 II l'/N 1 51 20 2 II % I II N 35 4 12 91 II 11 21 14 1 1 10 3 35 01 I/g I 10 N 0 15 1%

13 32 12 II 40 1 11 51 1 29 5 % 21 11 11 15 1%1 3 N 14 5% 24 1 11 12 I% 1 14 41 51 Illy I 31 11 11 II 21 ID 12 11 20 21 1 31 1 19 51/4 I 11 11 53 12 1% I 31 21 13 5% 25 II 4 11 12 I% I 20 1 II 1%1 I 51 21 5$ 5% 25 4$ 4 I/ 54 14 1 31 I 19 1 2 S 2 39 I% %1 II

51 13 11 21 21 1 5% 21 11 1 11 Ilk 1 11 I 1 1 1 l'i 11 11 21 11 55 51/4 20 N 11 II 35 I% 1 13 5 % 2 13 11 15 11 41 5% 11 30 31 13 2 2 9 11 3 15 % 1 32 i II 2 I 3 35 1 21 1 1 II 32 2% 0 1 I IA, 1 11 1 10

11 11 1% 21 11 SI II II 9 25 I 2% 0 12 1 % 2 50 2

IS 11 39 5 1% 21 II 31 II 29 31 1% I II 1 % 2 9 1 31 N 11 0% 21 15 II 11 52 33 2% I II 11 114/ 3 1 N 9 21 IS 1 13 2 II 1% 10 11 31 21 1% 1 11 li 1141 3 11 9 IS 25 11 32 12 0% 10 51 4 n V 11 55 2% 3 1 21 1 15 12 11 19 51 1% 31 15 11 11 2% 1 39 12 % 3 11 4

11 5 11 1% 11 9 10 15 3 I 11 0 1 % 3 g II 51 12 IS 31 1 1 12 II 12 11 11 3% 1 SI 11 25 1%1 3 V II 4 1 V i 42 II 1% 11 1 II I I 11 3% 1 0 21 % 1 N 41 N 0 11 1% 11 N 41 11 1 11 3% 1 0 11 % 1 11 It 55 1% 31 1 9 11 1 1 11 M 1 15 10 11 9 1141 1 11 14 20 II 10 34 % 1 21 21 11 12 3% 1 MACHINERY REPAIRMAN 3 & 2

unsaMIIMEMMED,

Table I-16.-Tapers In Inches (Brown and Sharpe)

MOWS COACT! TAM 1VePER FOOT

limit for plug depth ( P) kivwdy plug arbor tongue toper dla, at from arbor arbor tongue 'tongue to loper per small end of shankkeywaykeywaytongue tonguethick-circle tongue project no. foot end, for spindle,depth,length,width,length, dkck, nese radius,radius,through ass mill feet tool D eland, mach,misc. K S L W T d t c a

I 0.50200 0.20000 'Me "Al 1 %, 1i 0.135 VII 0.110 1/4 MG 0.030 0.003

2 0.50200 0.25000 1Ms 111/2, 11/2 1/2 0.111 % 0.220 '/ Ms 0.030 0.003

WI 1 "At 11/2 1/2 0.111 Me 0,212 VI, VI, 0.040 0.003 3 0.50200 0.31250 1% 1% 21/2 1/2 0.191 Me 0.212 Ms Ms 0,040 0.003

2 PA: 8', 1/4 0.111 IA, 0.212 Ms Ms 0.040 0.003

11/4 114 4 111/1/ "a, 0.221 11/41 0,320 1/4/ Ms 0,050 0.003 4 0.50240 0.35000 111/4, 14144 Nat "II g 0.221 I'M 0.320 1/4, Ms 0.050 0.003

1% 1"/Is 2'4s NI 0.210 1/4 0.420 1/4 Mg 0.010 0.003 S 0.50110 0.45000 2 1% 2'4, 1/2 0.210 1/4 0.420 Ni VI, 0.010 0.003

214 2' /,, 2' /,, V. 0.210 1/4 0,420 V. Ms 0.090 0.003

1 0.50329 0.50000 21/4 21%, 21/2 1/2 0.291 VI, 0.410 Mt Ms 0.010 0.005

21/4 2"4: 31/2: % 0.322 111/4: 0.510 Ms li 0.010 0.005 1 0.50141 010000 21/4 2% 3 "/,, "4, 0.322 "At 0.510 Ms 54 0.010 0.005 3 2% "II IV" 0.322 11/21 0.510 Ms 54 0.010 0.005

1 0.50100 0.15000 31/ is 31%, 41/4 I 0.353 1/4 0.110 HA: 1/4 0.000 0.005

4 31/4 4% 11/4 0.315 '4, 0.110 Ps 1/2s 0.100 0.005 11 0.50015 0,10010 4% 41/4 41/4 11/4 0.315 Yjs 0.110 1/4 1/4, 0.100 0.005

5 01/21 5% 11/2, 0,441 114, 1.010 'As YI, 0,110 0.005

10 0.51112 1.04415 51Ms 511/4, 111/4. WI, 0.441 71/41 1.010 1/11 'A, 0.110 0.005

I'M 1Ms 11Ms PM 0.441 "Ai 1.010 1/2s 1/2, 0.110 0.005

51%, 5"I, r' /" 11/2, 0,441 "Al 1.210 Ms '4 0.130 0.005 11 0.50100 1.24115 ______.- I% f 1/2: 1"/Ii Ns 0.441 21/4/ 1.210 'As 1/2 0.130 0.005 11/4 11/4 10/1, 1 M§ 11/4 0.510 % 1.410 1/4 1/4 0.150 0,006 12 0.49913 1.50010 114 ,

13 0.50020 1.15005 1% pm IM, 11/4 0.510 5', 1.110 1/4 1/4 0.110 0.010

14 0.50000 2.00000 114 11/4 10/o Wu I " a, 0.512 11/4: LW '46 % 0.110 0.010

15 0.50000 2.25000 1% 111/41 VIM 1"/is 0.512 % 2.210 Ms 1/2 0.210 0.010

11 0.50000 2,50000 9% 9 1014 11/4 0.135 114, 2,450 1/4 1 0.230 0.010

17 0.50000 2,15000 941,

11 0.50000 3.00000 101/4

AI -16 Table I.17.American Standard Tapers (Morsel

N 614 ,r, VONA

REAMER TEO 61T

i yf V / 41 PLUG GAGE A 4, 1I / IA ,...:s

diameter thank tang tong clot end of

plug at drilled reamed Ilan. WOtaper taper taperemail Oilwhole hole hole plugMild to tong per per dill no. end, line,length,depth,depth, depth, depth,neon, length, radius,dlo.,rodlue, width,length,clot, Inch foot cc

PABCM N OPEFGHJK L

0 0 1,112 121 NI NI NI hi 1 0,151 1/4 '/Ji 1'4I '44 VIII 944 1'44 1,052000 0,111111

I I 1,311 1,115 NI 21/41 21/16 1' /I 11/4 0,202 '4 'Ai 'IA? i4 1.113 1/4 Ni. 0,111112 1,11151

0,250 //ii i ''hr 1/3 0.211 '4 21/4 0,0111110,51111 1 2 On 1.130 21/4 211/4i 1% 2% Vii

1,111 11/41 31/3 0,1501111,10/35 1 3 0.111 0,111 11/4 311/41 0V 0'4 11/41 1.011 V 'iv 11/4r 1/44

1 1120 1,131 01 Iy, I 1y, I',, 0,119 Yi /it In lilt 0.119 ri 31/4 0.111131OMI

VI 111/11 % 1,105 11/4 1% 0,1511111.11151 5 5 1111 1.111 11/4 11/4 Pig 11/4 4'116 0115 li

I 2,116 2,181 PA, 114 111/1/ PA, 1% no 11/4 14 2 $4, 0160 PI 1 1.051111UM/5f

1115 1% 11/4 0,0510000,11110 1 1.111 1,111 11% 11% IN IN 11 1,115 11/4 1/4 11/4 1/41

DIrneniloni agree modally with thou of the Amerloon Standard on Machine Tam

4 The No 5 drift will alto Out Noi6 toper Iliad tole

0.' MACIINERY REPAIRMAN 3ft, 2

Table I-18.Drill Sizes For Ti.p.Ir Pins

Length

Small Lurge Diameter Diameter Drill sizesliti4.! 31approximately 0.005 smc Hee than small diameter

Taper 2 I/4 In. per foot

Small diameter r large diameter - length X 0.02083

MI MITI1/I 1/1 1/1 I/1 3/1 2/I I 2 3 ' 1 10 It 11AMIT11 AT LOUIS III 1.11211.171 1.114 1.111 0.121 1.141 0.101 0.172 1.113 0.211 0.250 0.211 0.141 0 401 0.412 0.511 0.707 1,157 if

111111211 DIANTEN OF SMALL END OF PIN ANC 0,111, SIZE LENITN 111731,1721 14 10 54 1.11471.17121,1112 Ih 51 45 Ih 1.11211,11711,1131 0.01111,11411.13010.1451 0.1111 Ih 12 41 34 31 944 54 1,14111,11111,1111 1,11100,11210,12101.1430 0.1511 Ih 1,44 7/, 12 '44 14 944 21

14 1.11111.11141.1714 1,11341,10141.12140,14040.15140.1;, 0.20340.2344 II 53 41 43 31 31 21 24 14., 1 I 1.11111.07110 /III1.10110,12210.13710.10310,174'1.20012.2311 14 41 43 37 31 21 21 11 1 0.01720.0732 0.01120,10420,12020.13520,11120.17120.11120.22120,21120.3202 14 II 44 31 32 30 21 II 10 2 0 14 0,11111,10116.11110,13110,14110,11110,11110.22110.21510.3111 1% 31 33 30 7/ II II 2 1

0.01300,01100.11000,1300.1410 11100.11300,22400,21300.3110 0.3130 41 33 14 6,4. 0 Vs /Ai F N I% 0 01140.11240.12740.14340.11140,11040,22140,21040,3124 0.3104 14 oh IA, 94 4 20 Me 3 I N 14 14 0.01310.10111.12410.14010.11111.11710,21110.21710.3011 0.3771 0,4101 1% 43 31 31 21 6/11 14 3 N U 1944 151 0.1041 3,33330,130, 0,1111 11200,21350,21210,3041 0.3725 0,4011 114 31 32 30 24 II 4 1:1 U

0.01130.'14,0,13030.11130.11130.22010,24130,1113 0.3113 0,41030.1414 2 41 34 54 21 "4, 144 C "At ?AI 174, 2% 1,12110.14110.17210,20310.24210.2141 0.31210,441!0.1442 24 21 27 II 1 1 T Ivo 24 ..11110,14010.11110.11710.13110,1111 :mu 0.43110,13100,1040 32 21 20 10 "At 'At 1 "At Ivo "At 251 0.13170.11170.11270.23170,2137 0.3017 0.43470,13310,1411 24 30 'At 'As I 1%1 8146 tt44

AI-18 Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-18.-Drill Sizes For Taper Pins-Continued

NV MIER 1/0 1/0 5/1 4/0 3/0 2/0 0 1 2 3 4 5 1 1 1 1 10 11

DIAMETER AT LARGE END 0.01250.011 0.014 0.101 0.125 0.141 0.151 0.112 0.113 0.211 0.250 0.211 0.341 0.401 0.412 0.111 0.101 0.151

LENGTH DIAMETER OF SMALL END OF PIN AND DRILL SIZE LENGTH

3 0.1305 0.1515 0.1115 0.2215 0.21150.34150.42150.52150.14350.1115 3

30 24 11 2 1 A "44 Wm 1/4 "/I4

31/4 0.11230.2213 0.21330.34130.42430.52330.13130.1123 31/4 I1 Yu 11/14 0 2 "1/44 % l/u 314 0.11110.21110.21110.33110.41110.51110.13310.1111 314 "44 3 0 0 Wu 1/2 1/4 H/s: 3% .. 0.21210.33010.41310.51210.12110.1111 31/4

F R1/44 WU % 11544 411/24

0.25110.32510.40110.50110.12210.1111 4 P Y 14 4,44 '%

41/4 0.32050.40350.10250.11151.1115 4% 0 0 "44 4144 4%4 0.31530.31130.11130.11230.7113 114 '/S4 "44 "44 10/u % 4% 0.31310.11210.111111.1111 43/4 W "44 %

0.31710.11111.11110.7111 1 y, 154, i,A, %

11/4 0.41110.51111.1501 51/4 IA, $4,4,

0.41150.11110.1455 114 u 114, 41,44

1% 0.17130.51130.1403 1% 211A4 /A, , /A,

1 . 0.41100.51100.1310 1 I% 'As "4, 11/4 0.17111.7211 I% '4. "At 114 0.17110.7211 114 11/1: 1% 0.51541.1114 1% iv% 44,44

7 0.51111.1142 1 4444 4%4

7% 1.1111 11/4 44,44 0.1031 SS "As MACHINERY REPAIRMAN 3 & 2

Table 1-19.--Grinding of Twist Drills

(Do Not Dip High-Speed Drills In Water)

Drilling different grades of materials sometimes requires modification of the commercial 118° drill point for maximum results. Hard materials require a blunter point with the more acute angle for softer materials. ANGLE OF POINTS Point

Fig. 1-19-1 Average Class of Work 118° included angle and 1-19-2 12° to 15° lip clearance

Fig. 1-19-3 Alloy Steele, Monel Metal, 125° included angle StainlessSteel,Heat 10° to 12° lip clearance TreatedSteels,Drop Forgings(Automobile Connecting Rods) Brinell Fig.I-19-3 Fig.I-19-4 Hardness No. 240

Fig. 1.19-4 Softand Medium Cast 90° to 130° included angle Iron, Aluminum, Marble, le lip clearance Slate, Plastics, Wood, Hard Flat cutting lip for marble Rubber, Bakelite, Fibre

Fig.I-19-5 Fig.I-19-6 Fig. 1.19-5 Copper, Soft and Medium [100° to 118° included angle Hard Brass 12° to 15° lip clearance 60° to 118° included angle Magnesium Alloys 15° lip clearance Slightly flat face of cutting lips reducing rake angle to 5 Fig.I-19-7 Fig. 1.19-6 Wood, Rubber, Bakelite, 60" included angle Fibre,Aluminum,Die 12° to 15° lip clearance Castings, Plastics

Fig. 1-19.7 Steel 7%to130 150° included angle Manganese, Tough Alloy 7° to 10° lip clearance Steels,Armor Plate and Slightly flat face of cutting hard materials lips

Fig. I-19.8 Brass, Soft Bronze 118° included angle 12° to 15° lip clearance Slightly flat face of cutting lips

Fig. 1.19-9 Crankshafts, Deep Holes In 118° Included angle Flg.I -19 -9 SoftSteel,HardSteel, Chisel Point \ CastIron,Nickeland 9° lip clearance +" Manganese Alloys Fig. 1.19-10 Thin Sheet Metal, Copper, -5° to +12° lip angles Fibre, Plastics, Wood Fordrillsover1/4" diameter make angle of bit Fig.1-19-10 point to suit work

AI-20 Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-20.-AllowancesFor Fits

(Grinding Limits for Cylindrical Parts

Diameter Limits Diameter Limits (inches) (inches) (inches) (inches)

Running Fits -- Ordinary Speed Driving Fits -- Ordinary

Up to1/2 - 0.00025 to -0.00075 Up to 1/2 0.00025 to + 0.0005 1/2 to 1 - 0.00075 to -0.0015 1/2 to 1 4- 0.001to + 0.002 1 to 2 - 0.0015 to -0.0025 1 to 2 + 0.002to + 0.009 2 to 3-1/2 - 0.0025 to -0.0035 2 to 3-1/2 + 0.009to + 0.004 3-1/2to 8 - 0.0035 to -0.005 3 -1/2 to 6 + 0.004to + 0.005

Running Fits -- High-Speed, Heavy Forced Fits Pressure and Rocker Shafts

Up to1/2 - 0.0005 to -0.001 Up to1/2 + 0.00075 to + 0.0015 1/2 to 1 - 0.001to -0.002 1/2 to 1 + 0.0015 to + 0.0025 1 to 2 - 0.002 63 -0.003 1 to 2 + 0.0025 to + 0.004 2 to 3-1/2 - 0.003to -0.0045 2 to 3-1/2 + 0.004to + 0.006 3-1/2to 6 - 0.0045 to -*-0.0065 3-1/2to 6 + 0.006to + 0.009

Driving Fits -- For such Pieces Sliding Fits as are Required to be Readily Taken Apart

Up to1/2 - 0.00025 to - 0.0005 Up to1/2 + 0 to + 0.00025 1/2 to 1 - 0.0005 to - 0.001 1/2 to 1 + 0.00025 to + 0.0005 1 to 1 - 0.001to -0.002 1-1/2to 2 + 0.0005 to + 0.0007! 2 to 3-1/2 - 0.002to -0.0035 2 to 9-1/2 + 0.00075 to + 0.001 3-1/2to 6 - 0.003to -0.005 3-1/2 to 6 + 0.001 to + 0.0015 101211111 ®m E3111 6911314 11111111© El J913E111111114911111111111111 FM s6121311111170111111211111111111 IliiiniCiinlii litEgili0 Nil IMEMIIIIIIIIKIBMINOCII EME1011111111115113" 1111111 1111111E Prililifillifiiiiiiiiiid 11111561113111MMERM1111111111 eon EI19 Mel DEEM DM I 1041111111161101211111111111 Ommmm ®m Om 1381311MIEV9132111111111 ...loomNED ma9' IMBEEMIEN1132198111111IMMI BE J9inchioni ©®111118011111111310 g111111111111 nom.9 En mai ..riennum ma EEGam 6, mug0081111111111 IMO91 11111111 /6 OM 0 en MINE=13118111111111M01110111110E1 6Eime a mil 65 ODOM MEEMEM918111911 1:161 Ela Enlinglarl56 DOMIIIMDC: MIME IS IDEZEINIENICI ON /1111111111111 I " MEI IMICIERIDOWISOSIOCIIIIIIIMECIIIIIIIIII ODIECIIMEMEIE11111613 m ©® 1111111116M Q1111111111, MIN DOME One ©m ommum193 comma; , LEXICIOMMIll ,6 non 11112 MI 13111111 033110=11111111 CI MEIN II r101111111113 MOICIMIZIECI esommoma all TUE 19 0 ...... r... 13 cron 1 11 nagninci otim11111111 Eril 31 CI IIIIMMICED II Oualagli gpm1111FECI DIEGEIDIMEIDIES WI owilidrumm 9E1U° IIII

Graduations in tableare for setting of the arms of sector when index crank moves through arc "A", except when marked when the Index crankmoves through arc "B",

=====fmtn1141!A111141U Ilammummomm9WW I I MI

I Appendix I-TABULAR INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Table I-22.-Machinability Ratings/Other Properties of Various Metals

Tensile Yield Elongation , Reduction Machinability SAE AISI Strength Point in 2 in. In Area Hardness Rating Number Number psi psi ( % ) ( To ) Brinell ( %)

Carbon Steels

1015 01015 65,000 40,000 32 65 137 50 1020 C1020 67,000 45,000 32 65 137 52 x1020 C1022 69,000 47,000 30 58 143 62 1025 C1025 70,000 41,000 31 58 130 58 1030 C1030 75,000 46,000 30 56 138 60 1035 C1035 88,000 55,000 30 56 175 60 1040 C1040 93,000 58,000 27 52 190 60 1045 C1045 99,000 60,000 24 47 200 55 1095 C1095 10C 000 60,000 23 47 201 45

Free-Cutting Steels

x1113 B1113 83,000 73,000 15 45 193 120.140 140 100 . 1112 81112 67,000 40,000 27 477, C1120 69,000 36,000 32 55 117 80

Manganese Steels

x1314 71,000 45,000 28 52 I 135 94 x1335 A1335 95,000 I 60,000 20 35 185 70

Nickel Steels

2315 A2317 85,000 6,000 29 60 163 50 2330 A2330 98,000 65,(,00 25 50 207 45 2340 A2340 110,000 5,000 22 47 225 40 2345 A2345 108,000 75,000 23 46 235 50

Nickel-Chromium Steels

3120 A3120 75,000 60,000 30 65 151 50 3130 A3130 100,000 72,000 24 55 212 3140 A3140 96,000 64,000 26 56 195 3150 A3150 104,000 73,000 19 51 229 JJ 3250 107,000 75,000 24 55 217 44

Molybdenum Steels

4119 91,000 52,000 28 62 179 60 x4130 A4130 89,C )0 60,000 32 65 179 58 .:140 A4140 90,000 63,000 27 58 187 56 4150 A4150 105,000 71,000 21 54 220 54 x4340 A4340 115,000 95 000 18 45 235 58 4615 A4615 82 000 55,000 30 61 167 58 4640 A4640 100,000 87,000 21 50 201 60 4815 A4815 105,000 73,000 24 58 212 55

AI-23 5 u MACHINERY REPAIRMAN 3 & 2

Table l-22.-Machinability Ratings/Other Properties of Various Metals-Continued

Tensile Yield Elongation Reduction Machinability SAE AISI Strength Point in 2 in. in Area Hardness Rating Number Number psi psi (%) (%) P-inell (%)

Chromium Steels

5120 A5120 73,000 55,000 32 67 143 50 5140 A5140 174-229 60 52100 E52101 109,000 80,000 25 57 235 45

Chromiuni-Vandium Steels

6120 I A6120 179-217 50 6 .30 A6150 103,000 70,000 27 51 217 50

Other Alloys and Metals

Aluminum i i 1S) 40.000 42,000 14 95 300-2,000 Brass, Leoded 55,000 45,000 32 RF 100 150 -600 Blass, Red or Yellow 75.35,000 15-30,000 40-55 200 11ratize 10.00 jawing 22-32,000 8-20,000 3-16 5-18 30-65 200-500 Cost Iron, Hcrd 45,000 220-240 50 Cost Iron, Medium 40,000 193-220 65 Cost Iron, Soft 30,000 160-193 80 Cost Steel '0.35 C) 86,000 55,000 25 34 170-212 70 Copper (F. M.) 35,000 33,000 34 RF 85 65 Ingot Iron 41-45,000 18-25,000 45 70 101-131 50 Low-Alloy, High- Strength Steel 98,000 65,000 18 34 187 80 Mognesium Alloys 500-2,000 Molleable Iron Stondord 53-60,000 35-40,000 18-25 110-145 120 Peo rlitic 80,000 55,000 14 480-200 90 Peo rlitic 97,000 75,000 4 \ 227 80 Stoinless Steel 12`',. Cr F.M. 120,000 86,000 23 64 207 70 18-8 Stoinless Steel (Type 303 F.M.i 80,000 30,000 60 75 150 45 18-8 Stainless Steel (Type 304) 80,000 40,000 65 70 150 25

Properties for wrought materials are for hot-rolled Condition. Properties in this table are only a rough guide to the machining of various common steels and alloys.

AI-24 Appendix ITABULAit INFORMATION OF BENEFIT TO MACHINERY REPAIRMAN

Tabic 1-23.Selection Chart for Cutting Fluids

Ferrous Metals Nonferrous Metals

Group I II HI IV V VI Machinability Ow 70 % 30-70 %40-50 % Under 40 %Over 100 %Undii 100%

Materials LowcarbonSteels StainlessSteels Aluminumand Alleys HighcarbonSteels Ingot Iron Tool Steels Brasses andBronzes Malleable Iron Cast Iron Wrought Iron Highspeed Magnesium Copper Cast Steel Steels and Alloys Nickel Stainless Iron Zinc Inconel Monel Severity Type of Machining Operation

(Grelest) 1. Broaching, internal Em. Sul. Sul. Em. Sul. Em. Sul. Em. MO. Em. Sul. ML.

2. Broaching; surface Em. Sul. Em. Sul. Sul. Em. Sul. Em. MO. Em. Sul. ML.

2. Threading; pipe Sul. Sul. ML Sul. Sul. Sul.

3. Tapping; plain Sul. Sul. Sul. Sul. Em. Dry Sul. ML.

3. Threading; plain Sul. Sul. Sul. Sul. Em. Sul. Sul. 4. Gear shaving Sul. L. Sul. L. Sul. L. Sul. L.

4. Reaming; plain ML. Sul. ML. Sul. ML. Sul. ML. Sul. ML. MO. Em.ML. MO. Sul.

4. Sul. ML. Em.Sul. Sul. Sul. ML. Sul. ML.

5. Drilling; deep Em. ML. Em. Sul. Sul. Sul. MO. ML. Em.Sul. ML.

6. Milling; plain Em. ML. Sul. Em. Em. Sul. En.. MO. DrySul. Em.

6. Milling; multiple cutter ML. Sul. Sul. Sul. ML. Fm. MO. DrySu!. Em.

7. Boring; multiple head Sul. Em. Sul. HDS Sul. HDS Sul. Em. K. Dry Em. Sul. Em.

7. Multiplespindle automatic screw maSul. Em. ML.Sul. Em. ML.Sul. Em. ML.Sul. ML. Em.Em. Dry ML. Sul. chines and turret lathes: drilling, HDS HDS forming, turning, reaming. cutting.

off, tapping, threading . 8. High speed, light feed automatic screw Sul. Em. ML.Sul. Em. ML.Sul. Em. ML.Sul. ML. Em.Em. Dry ML. Sul. machines: driiling, forming, tapping, threading, turning, reaming, boa mill- ing, cutting off 9. Drilling Em. Em. Em. Em. Sul. Em. Dry Em. 9. Planing, shaping Em. Sul. ML.Em. Sul. ML.Su/. Em Em. Sul. Em. Dry Em.

9. Turning; single point tool, form tools Em. Sul. ML.Em. Sul. ML.Em. Sul. ML.Em. Sul. ML.Em. Dry ML.Em. Sul.

(LPast) 10. Sawing; circular, hack Sul. ML. Em.Sul. Em. ML.Sul. Em. ML.Sul. Em 'ML.Dry MO. Em.Sul. Em. ML. Grinding; 1. plain Em. Em. Em. Em. Em. Em. 2. form Sul. Sul. Sul. Sul. MO. Sul. Sul. (thread, etc.)

%-..1 Key K.= Kerosene Sul.= Sulphurized Oils, with or without chlorine 1..=Lard Oil Em.=Soluble or emulsifiable oils and compounds MO.=Mineral oils Dry= No cutting fluid needed MI..=Mineral-lard oils HDS= Heavy duty soluJe oil

AI-26' ) APPENDIX II FORMULAS FOR SPUR GEARING

Having To Get Rule Formula 3'1416 Diametral pitch Circular pitch Divide 3.1418 by theCP = diametral pitch DP Pitch diameter and OD number of teeth. Circular pitch Divide the pitch di- PD ameter by the 0.3183 NT product of 0.3183 and the number of teeth. OD Outside diameter andCircular pitch Divide the outside CP number of teeth. diameter by the 0.3183 NT + 2 product of 0.3183 and the number of teeth plus 2. Number of teeth and Pitch diameter The product of the PD = 0.3183 CP NT circular pitch. number of teeth, the circular pitch, and 0.3183. N OD Number of teeth and Pitch diameter Divide the product PD NT+ 2 outside ii...meter. of the number of teeth and the out- side diameter by the number of teeth plus 2.

Outside diameter andPitch diameter ----Subtract from the PD = OD - 0.6366 CP circular pitch. outside diameter the product of the circular pitch and 0.6368. Addendum and num- Pitch diameter ----Multiply the num- PD = NT ADD ber of teeth. ber of teeth by the addendum. Number of teeth and Outside diameter-- The product of the OD = (NT + 2) 0.3183 CP circular pitch. number of teeth plus 2, the cir- cular pitch, and 0.3183. MACHINERY REPAIRMAN 3 & 2

Having To Get Rule Formula Pitch diameter and Outside diameter--Add tc the pitch OD = PD + 0.6366 CP circular pitch. diameter the product of the circular pitch and 0.6366. Number of teeth and Outside diameter-- Multiply the adden- OD = (NT +2)ADD addendum. dum by the num- ber of teeth plus 2. Pitch diameter and Number of teeth -- Divide the product NT=3'1416PD circular pitch. of the pitch di- CP ameter and 3. 1416 by the circular pitch. CP Circular pitch Chordal Thickness -- One half the cir- (tc) cular pitch. Circular pitch Addendum Multiply the cir- ADD = 0.3183 CP cular pitch by 0.3183. Circular pitch Working depth - - -- Multiply the cir- WKD = 0.6366 CP cular pitch bi 0.6366.

Circular pitch Whole depth Multiply the cir- WD = 0.6866 CP cular pitch by 0.6866. Circular pitch Clearance Multiply the cir- CL= 0.05 CP cular pitch by 0.05. 3.1416 Circular pitch Diametral pitch Divide 3.1416 by DP the circular CP pitch. NT Pitch diameter and Diametral pitch Divide the number DP= p-D- number of teeth. of teeth by the pitch diameter. PD PDP Pitch diameter of Center distance- - - Add pitch diameter C g2+ gear and pinion. of gear (PDg) to pitch diame4. pinion (PDp) divide by 2. Outside diameter andDiametral pitch--- Divide the numoer DPNT =- + 2 number of teeth. of teeth plus 2 by 01) the outside di- ameter. Appendix IIFORMULAS FOR SPUR GEARING

Z=t riaving T> Get Rule Formula Number of teeth and Pitch diameter -- Dl,ide the number PD=NT diametral pitch. f teeth by the DP diametral pitch.

Outside diameter andPitch diameter -- Subtract from the PD = OD diametral pitch. outside diameter DP the quotient of 2 divided by the diametral pitch. NT +2 Number of teeth and Outside diameter-- -Divide the number OD = DP diametral pitch. of teeth plus: 2 by the diametral pitch. 2 Pitch diameter and Outside diameter Add to the pitch OD = PD + diametral pitch. diameter the DP quotient of 2 divided by the. diametral pitch. .NT Pitch diameter and Outside diamet-r Divith? the number OD = NT + 2 number of teeth. of teeth plus 2 -"PD by the quotient of the number of teeth divided by pitch diameter. Pitch diameter and Number of teeth Multiply the pitch NT = PD DP diametral pitch. diameter by the diametral pitch. Outside diameter Number of teeth Multiply the out- NT = OD DP 2 and the diam- side diameter by etral pitch. the diametral pitch and sub- tract 2. 1.5708 Diametral pitch Chordal Thickness - Divide 1.5708 by DP the diametral pitch.

Diametral pitch ddendum------Divide 1 by the ADD = 1 diametral pitch. DP

Diametral pitch Working depth-- Divide 2 by the WKD = diametral pitch. DP 2157 Diametral pitch Whole depth Divide 2.157 by WD ='DP the diametral pitch. - 0.157 Diametral pitch Clearance Divide 0.157 by CL-- the diametral pitch. AII-6L' APPENDIX III DERIVATION OF FORMULAS FOR DIAMETRAL PITCH SYSTC:1

1. TOOTH ELEMENTS based on a #1 diametrai (2) Measure the pitch on the pitch gear (fig. III-A). pitch line. If yu..k . ; craw a circle inside the ,.1 tch ADD a. Addendum (ADD) - 1.000 as the diametc;. th+' of thecircle wo b:.;.1 n16.:'sing (1) The distance from the top of the your imag,inatinH break the at tooth to the pitch line. onepointonthecit.; urnfe:cence, imaginingthe string. Lay the imaginary, string on b. Circular Pitch (CP) - 3.1416 the pitch line at one side of the tooth. Stretchtheother end asraras (1) The length of an arc equal to the possible on the pitchline:itwill ci-cumference of a one-inch circle, stretch to a corresponding point on covers one tooth and one space on the next adjacent tooth on the pitch the pitch circle. line.

78.43 Figure III-A.Tooth elements on a #1 diametral pitch gear.

All I -1

._57, MACHINERY RFPAIRMAN 3 & 2

c. Circular Thickness (CT) - 1.5708 j. Chord, Thickness - t, (1) One-half ofthecircularpitch, (1) The thickness of the tooth, measured measured at the pitch line. at the pitch circle. d. Clearance (CL) - 0.15708 t, = PDsin(C (1) One-tenth of the chordal thickness; move decimal one place to the left. 2. GEAR ELEMENTS e. Dedendum (DED) - 1.15708 e. Number of Teeth (NT) (1) The sum of an addendum plus a clearance. (1) Connecting link between the tooth elements and gear elements (2) 1.000- ADD + .1570 - CL (2) Number of teeth in gear 1.1570 - DED

f. Working Depth (WKD) - 2.000 (3) ADD= DNT

(1) The sum of two addendums. Pitch Diameter (PD)

(2) 1.000 - ADD (1) Diameter of the pitch circle. +1.000 - ADD 2.000 - WKD (2) Fol ever' 400th in the geal there is an ade iclum on the pitch diameter. g. Whole Depth (WD) - 2.15708 (3) ADD x NT = (PD) (1) The sum of an addendum and a dedendum. c. Outside Diameter (OD)

(2)1.000- ADD (1) The eqameter of the gear +1.1570 - DED 2.1570 - WD (2) Since there is an addendum ('ADD) on thepits-itdiameter (PD) for each h. Diametral Pitch (DP) - re tvbo elements axdirect!,' related.Therefore,theoutsic (1) The ratio of the number of teeth par diameter is simply the pitch cliarnetf; inch of pitch diameter. (PD) plus two addendums (A.OD), or F.'-nulai.ed teeth. The formulas read: (2) Try=NT DP (a) ADP YNT =PD L Chordal Addendum ac (b) ADD X (NT + 2., = )D or (1) The distance from the top of a gear toothtoachordsubtending (c) PD + 2 ADD - OD (extending under) the intersections of the tooth thickness arc and the sides a. Linear Pitch (LP) of the tooth. frrro (2) ac = ADD+ (1) The linear patch is the same as the 4(PD) circular pitch except that itis the AIII-2 Appendix IIIDERIVATION OF FORMULAS FOR DIAMETRAL PITCH SYSTEM

lineal measurement of pitch on a gear FORMULAS rack.

(2) CP = L2 1 00 1. ADD (3) Figure III-B illustrates linear pitch. DP 3 1416 3. GEAR AND TOOTH ELEMENT 2. CP'DP RELATIONSHIP 1.57085708 TOOTH GEAR 3. CT a. ADD h. PD 4. CL '15708 b. DED i. OD DP 1'15708 c. CP ac 5. DED DP d.CT k. tc 2.000 6. WKD e. WD DP 2.15708 f. CL 7. WD DP g. DP 8. DP =12L.Tpr, or transpose any other (1)NT is the connecting link between formula with DP involved. tooth elements and gear elements. (2)To complete calculate a gear, one 9. Kyr PD tooth and one gear element must be "1 ADD known. (3)For every tooth in the GEAR there is 10. PD = ADD X NT a CP on the PC. (4)For every tooth in the GEAR there is an ADD on the PD. 11. OD = ADD X (NT + 2)

LINEAR TOOTH 41--PITCH ADDENCUM THICKNESS

28.439 Figure III-B.Linear pitch.

AIJI-3 LJ APPENDIX IV

GLOSSARY

When you enter a new occupation, you must ARBOR: The principalaxis member, or learn the vocabulary of the trade so that you spindle, of a machine by which a motion of understand your fellow workmen and can make revolution is transmitted. yourself understood by them. Shipboard life requires that Navy personnel learn a relatively ASTM: American Society for Testing Metals. new vocabularyeven new termsfor many commonp.ace items. The reasons for this need BABBITT: A leadbasealloyusedfor are many, but most of them boil down to bearings. conveniencean d safety.Undercertain circumstances, a word or a few words may mean an exact thing or may mean a certain sequence BEND ALLOWANCE: Anadditional of actions which makes it unnecessary to give a amount of metal used ina bend in metal lot of explanatory details. fabrication.

This glossary is not all-inclusive, but it does BENCH MOLDING: The process of making contain many termsthatevery Machinery small molds on a bench. Repairman should know. The terms given in this glossary may have more than one definition; BEVEL: A term for a plane having any angle onlythosedefinitionsasrelatedtothe other than 900 to a given reference plane. Machinery Repairman are given. BINttRY ALLOY: An alloy of two metals. AISI: American Iron and Steel Institute. BISECT: To divide into two equal parts. ABRASIVE: A hard, tough substance which has many sharp edges. BI,OWHOLE: A hole in a casting caused by trapped air or gases. ALLOWANCE:Differencebetween maximum size limits of mating parts. BOND: Appropriate substance used to hold grains together in grirliding Wheels. ALLOYING: Procedure of adding elements other than those usually comprising a metal or BORING BAR: A tool used for boring, alloy to change its characteristics and properties. counterboring, reboring, facing, grooving, etc. where true alignment is of primary importance. ALLOYING ELEMENTS: Elements added to nonferrous and ferrous metals and alloys to BRINELL: A type of hardness test. change their characteristics and properties. BRITTLENESS: That property of a material ANNEALING: The softening of metal by which causes it to break or snap suddenly with heating and slow cooling. little or no prior sign of deformation.

AIV-1 5-, oMACHINERY REPAIRMAN 3 & 2

BRONZE: A nonferrous alloy composed of FINISH MARKS: Marks used to indicate the copper and tin and sometimes other elements. degree of smoothness of finish to be achieved on surfaces to be machined. CALIBRATION: The procedure required to adjust an instrument or device to produce a GRAIN: The cutting edges of a grinding standardized output with a given input. wheel.

CARBON: An alloying element, HARDNESS: The ability of a material to is.sist penetration. CASTING: A metal object made by pouring melted metal into a mold. HELIX: A groovewhichadvances longitudinally on a cylindrical object. CHAMFER: A bevelsurface formed by cuttingawaytheangleofoneortwo HONING: Finishingmachineoperation intersecting faces of a piece of material. using stones vice a tool bit or cutting tool.

CONTOUR: The outline of a figure or body. INVOLUTE: Usually referred to as a cutter used in gearing. : A conical-shaped pin gradually tapered from a blunt point to a diameter larger JIGS: A fixed fixture used in production than the hole diameter. machining,ortoholdaspecific jobfor machining. DUCTILITY: The ability to be molded or shaped without breakage. KNOOP: Trade name usedinhardness testing. EXTRACTORS: Tool used in removal of MANDREL: Tool usedto mount work broken tape. usually done in a lathe, or milling machine.

FABRICATE: To shape,assemble,and NORMALIZING: Heating iron-base alloys to secure in place the component parts in order to approximately 100°Fabovethecritical form a complete whole for manufacture. temperature range followed by cooling to below that range in still air at ordinary temperature. FALSE CHUCK: Sometimes applied to the facing material used in rechucking a piece of OCCUPATIONAL STANDARDS: Require- work in the lathe. ments that are directly related to the work of each rating. FATIGUZ: The tendency of a material to break under repeated strain. PERISCOPE: Aninstrumentusedfor observing objects from a point below the object FILE FINISH: Finishing a metal surface lens. It consists of a tube fitted with an object with a file. lens at the top, an eyepiece at the bottom and a pair of prisms or mirrors which change the FILLET: A concave internal corner ina direction of the line of sight. Mounted in such a metal component. manner that it may be rotated to cover all or a part of the horizon or sky and fitted with a scale FINISH ALLOWANCE: An amount of stock graduated to permit taking of bearings, it is used left upon the surface of acasting forthe bysubmarinestotakeobservationswhen operation of machine finish. submerged. Appendix IVGLOSSARY

PERPENDICULAR: Vertical lines extending SPOT FACING: Turning a circular bearing through the outlines of the hull ends and the surface about ahole.Itdoes not affect a designer's waterline. pattern. PIG IRON: Cast iron as it comes from the STANDARD CASING: The half of a split blast furnace in ,which it was produced from iron casing thatisbolted tothe foundation, as ore. opposed to the half, or cover, which can be removed with minimum disturbance to other PINHOLE: Small hole under the surface of elements of the equipment. the casting. STRAIGHTEDGE: Relatively long piece of PLAN: A drawing preparedforusein material having one or both edges a true plane. building a ship. STRENGTH: The ability of a material to PLASTICITY: That property which enables resist strain. a material to be excessively and permanently deformed without breaking. STRESS RELIEVING: Heat treatment to remove stresses or casting strains. PREHEATING: The application of heat to the base metal before it is welded or cut. STUD:(1)Alightverticalstructure member, usually of wood or light structural PUNCH, PRICK: A small punch used to steel, used as part of a wall and for supporting transfer the holes from the template to the moderate loads. (2) A bolt threaded or. both plate. Also called a CENTER PUNCH. ends, one end of which is screwed into a hole drilled and tapped in the work, and is used QUENCHING: Rapid cooling of steels at where a through bolt cannot be fitted. different rates. SYNTHETIC MATERIAL:A complex REAMING: Enlarging a hole by the means chemical compound which is artificially formed of revolving it in a cylindrical, slightly tapered by the combining of two or more simpler tool with cutting edges running along its sides. compounds or elements. RECHUCKING: Reversing of opiece of TEMPER: To relieve internal stress by heat work upon a faceplate so that the surface that treating. /as against the faceplate may be turned to shape. TEMPLATE: A pattern used to reproduce parts. REFERENCE PLANE: On a drawing, the normal plane from which all information is TOLERANCE: An allowable variation in the referenced. dimensions of a machined part.

RPM: Revolutions per minute. VICKERS: A scale or tect used in metal hardness testing. SCALE: The ratio between the measurement used on a drawing and the measurement of the VITRIFIED BOND: A ma, made bond used object it represents. A measuring device such as in grinding wheels. a ruler, having special gradations. WAVINESS: Used as a term in the testing of SECTOR: A figure bounded by two radii finish machining of parts. and the included arc of a circle, ellipse, or other central curve. ZINC: An alloy used widely in die casting.

AIV-3

5 frlA., INDEX

A Annealing, 4-19, 4-20 Anode materials, plating tool, 14-34, 14-35 Apron, 7-7, 7-8 Acid test, 4-18, 4-19 Arbor and hydraulic presses, 3-34, 3-35 Activating, 14-59 Arbors, 11-31 to 11-35 Adhesion, evaluating, 14-63 Adjustable gages, 2-5 to 2-11 Assemblies, shaper, 12-1 to12-4 adjustable parallel, 2-10 crossrail, 12-3 cutter clearance gage, 2-9,2-10 drive, 12-2, 12-3 dial bore gage, 2-8 main frame, 12-1 dial indicators, 2-5, 2-6 table feed mechanism, 12-3, 12-4 dial vernier caliper, 2-8 toolhead, 12-4 gear tooth vernier, 2-9 Assignments and duties, typical, 1-2 internal groove gage, 2-8 Attachments, 11-10, 11-11, 11-58 to 11-61 surface gage, 2-10, 2-11 milling machine, 11-58 to 11-61 universal bevel, 2-8 special, 11-10, 11-11 universal vernier bevel protractor, 2-8 vernier caliper, 2-6, 2-7 Attachments and accessories, lathe, 7-15 to 7-27 vernier height gage, 2-7, 2-8 carriage stop, 7-24, 7-25 Adjustable parallel, 2-10 center rest, 7-22, 7-23 Advanced engine lathe operations, 9-1 to 9-25 follower rest, 7-23 buttress thread, 9-13, 9-14 grinding attachment, 7-25 classes of threads, 9-14, 9-15 lathe centers, 7-21, 7-22 measuring screw threads, 9-15, 9-16 lathe chucks, 7-18 to 7-21 pipe threads, 9-la lathe dogs, 7-22 ring and plug gages, 9-16 to 9-25 mining attachment, 7-25 screw threads, 9-8 to 9-13 taper attachment, 7-23, 7-24 straight pipe threads, 9-14 thread dial indicator, 7-24 tapered pipe threads, 9-14 toolholders, 7-16 to 7-18 tapers, 5- 1 to 9-8 toolposts, 7-16 thread micrometer, 9-16 tracing attachments, 7-25, 7-26 Alloy steels, 4-6 Aluminum alloys, 4-8 Angular cutters, 13-18 B Angular holes, drilling, 5-28 to 5-31 equipment, 5-29, 5-30 operation, 5-30, 5-31 Ball valves, 15-19 to 15-21 Angular indexing, 11-15, 11-16 Bandsaws, metal cutting, 5-5 to 5-18 Angular milling, 11.40 to 11-46 Base material, verifying identity of, :4-59, 14-60

I-1 573 MACHINERY REPAIRMAN 3 & 2

Basic engine lathe operations, 8-1 to 8-26 Cemented carbide, 6-16 to 6-19 knurling, 8-23 to 8-26 brazed on tip, 6-16, 6-17 machining operations, 8-15 to 8-20 carbide cutting tools-insert type, 6-17 methods of holding the work, 8-6 to 8-15 to 6-19 parting and grooving, 8-20 to 8-23 Center rest and follower rest, using, 8-14, 8-15 preoperational procedures, 8-1, 8-2 Center rest, lathe, 7-22, 7-23 setting up the lathe, 8-2 to 8-6 Centers, lathe, 7-21, 7-22, 8-3 to 8-5, 8-6 to 8-8 Bed and wars, 7-1 to 7-4 holding work between, 8-6 to 8-8 preparing, 8-3 to 8-5 Bench and pedestal grinders, 6-2 Chip breaker grinder, 6-12 to 6-14 Benchwork, 3-22 to 3-48 Chucks, holding work in, 8-10 to 8-12 fastening devices, 3-40 to 3-48 draw-in collet chuck, 8-12 precision work, 3-23 to 3 -38 four-jaw independent chuck, 8-10, 8-11 safety: oxyacetylene equipment, 3 -38 to rubber flex collet chuck, 8-12 3-40 three-jaw universal chuck, 8-11, 8-12 Blade selection, power hacksaws, 5-2, 5-3 Chucks, lathe, 7-18 to 7-21 Blueprints and mechanical drawings, 3-1 to 3-10 Circular copy plate, using a, 12-32 Boring, &22, 8-23, 9-6 to 10-29 to 10-25, Circular milling attachment, 11-59 Classes of threads, 9-14, 9-15 11-57, 11-58 1. forming, 10-20, 10-21 Clearance angle, setting the, 13-13 to 13-15 grinding boring cutters, 10-20 Coating, application of, 14-7, 14-8 taper, 9-6 to 9-8 Combination boring and facing head, 11-67 to taper turning, 10-23 to 10-25 11-69 threading, 10-21, 10-22 Components, horizontal turret lathes, 10-3 to 10-8 Boring mill operations, 11-69 to 11-72 feed train, 10-5 Broaching, 3-26 feed trips and stops, 10-5 to 10-7 Brinell hardness test, 424 headstock, 10-3 to 10-5 Brittleness, metals, 4-2 threading mechanism, 10-7, 10-8 Broken bolts and studs, removing, 15-33 to ! 3 -36 Compound indexing, i 1-16, 11-17 Buttress thread, 9-13, 9-14 Constant-pressure governor, 15-23 to 15-26 Contact electroplating, 14-12 to 14-25 applications, 14-21, 14-22 C health and safety precautions, 14-16, 14-17 limitations, 14-22, 14-23 operator qualification, 14-16 Calibration servicing labels and tags, 15-42 to plating tool coverings, 14-16 15-45 plating tools, 14-14, 14-15 Carbide tool grinder, 6-10, 6-11, 6-1 2 power pack, 1413, 1414 operation of, 6-11, 6-12 processing instructions, 14-23 Carbon tool steel, 6-15 quality control, 14-23 to 1425 Care and maintenance of gages, 2-19 to 2-21 solutions, 14-16 dials, 2-21 terminology, 14-17 to 14-21 mizrometers, 2-19, 2-20 Continuous feed cutoff saw, 5-4, 5-5 vernier gages, 2-20, 2-21 band se:ection and installation, 5-4, 5-5 Carriage, 7-6, '1 -7 operation, 5-5 Carriage, holding work on the, 8-13 Coolants, 11-64, 13-3, 13-4 Carriage stop, lathe, 7-24, 7-25 Copper alloys, 4-7 Case hardening, 4-21 Corrosion resistance, metals, 4-3 Cast alloys, 6-16 Counterboring, countersinking, and spotfacing, Cast iron, 4-5 5-27 INDEX

Cross traverse table, surface grinder, 13-4, 13-5 Double seated valves, 15-27 Cutter clearance gage, 2-9, 2-10 Draw-in collet chuck, 8-12 Cutters and arbors, 11-20 to 11-35 Drilling and reaming, 8-21, 8-22 arbors, 11-31 to 11-35 Drilling machines and drills, 5-18 to 5-28 cutters, 11-20 to 11-31 drilling operations, 5-23 to 5-28 Cutter sharpening, 13-11 to 13-13 safety precautions, 5-19 Cutter sharpening setups, 13-15 to 13-22 twist drill, 5-21 to 5-23 angular cutters, 13-18/ types of machines, 5-19 to 5-21 end mills, 13-18 to 13121 Drilling, reaming, and boring, I 1-,i7, 11-58 formed cutters, 13-21, 13-22 Ductility, metals, 4-2 plain milling cutters (helical teeth), Duplex strainer plug valves, 15-27 13-15, 13-16 Duties and assignments, typical, 1-2 side milling cutters, 13-16 staggered tooth cutters, 13-17, 13-18 Cutter speeds, pantographs, 12-22 E Cutoff saw, continuous feed, 5-4, 5-5 Cutting speeds and feeds, 8-15 to 8-18 chatter, 8-17 Elasticity, metals, 4-2 coolants, 8-17 Electroplating, contact, 14-12 to 14-25 direction of feed, 8-18 End mills, 13-18 to 13-21 Cutting tool materials, 6-15 Engineering handbooks, 178 Cylindrical grinder, 13-8 to 13-10 Engine lathe, 7-1 to 7-15 sliding table, 13-8, 13-9 apron, 7-7, 7-8 using the, 13-9, 13-10 bed and ways, 7-1 to 7-4 wheelhead, 13-9 carriage, 7-6, 7-7 compound rest, 7-15 feed rod, 7-8, 7-9 D gearing, 7-9 to 7-15 headstock, 7-4, 7-5 lead screw, 7-9 Deposits, evaluating, 14-63 tailstock, 7-5, 7-6 Depth micrometer, 2-18 Engine lathe cutting tools, grinding, 6-19 to 6-21 Depth of cut, 13-2, 13-3 Engine lathe operations, basic, 8-1 to 8-26 Derivation of formulas for diametral pitch system, Fngraver units, pantograph, 12-18 to 12-21 AIII-1 to AIII-3 copyholder, 12-21 Designations and markings of metals, 4-8 to 4-l3 cutterhead assembly, 12-18 to 12-21 ferrous metal designations,, 4-9 to 4-11 pantograph assembly., 12-18 nonferrous metal designations, 4-11 to supporting base, 12-18 4-13 worktable, 12-21 Desmutting, 14-59 Engraving, 12-32, 12-33 Dial bore gage, 2-8 dial face, 12-32, 12-33 Dial face, engraving, 12-2,2, 12-33 graduated collar, 12-32 Dial indicators, 2-5, 2-6 Etching, 14-59 Dial vernier caliper, 2-8 External keyseat, 11-47, 11-48 Diametral pitch system, 15-11 to 15-13 Dies and hand taps, 3-26 to 3-31 Differential indexing, 11-17 to 11-20 Direct indexing, 11-12, 11-13 Disintegrators, metal, 5-31 to 5-33 Dividing head, 11-7 to 11-9 Facing, 8-18 Dogs, lathe, 7-22 Face milling, 11-37 to 11-40

1-3 5 MACHINERY REPAIRMAN 3& 2 Faceplate, holding work on a, 8-12, 8-13 G Fastening, devices, 3-40 to 3-48 gaskets, 3-47 keyseats and keys, 3-44 to 3-46 Gaskets, 3-47 packing, 3-47, 3-48 Gate valve, 15-21 to 15-23 pins, 3-46, 3-47 Gearing, 7-9 to 7-15 seals, 3-48 idler gears, 7-10 to 7-12 screw thread inserts, 3-42 to 3-44 quick-change gear mechanism, 7-12to 7-15 threaded fastening devices, 3-40to 3-42 Gears, 15-8 to 15-14 Gear tooth vernier, 2-9 Fatigue, metals, 4-3 Feed rod, 7-8, 7-9 Glove valves, 15-17 to 15-19 Feeds and speeds, Glossary, AIV-1 to AIV-3 power hacksaws, 5-3 Graduated collar, engraving, 12-32 Feeds, speeds, and coolants,11-61 to 11-64 Graduated gages, 2-11 to 2-14 coolants, 11-64 Grinding and machining, 14-65 feeds, 11-62 to 11-64 Grinding attachment, lathe, 7-25 speeds, 11-61, 11-62 Grinding cutters, pantographs,12-22 to 12-30 Feed train, 10-5 single-file cutters, 12-23 to 12-29 square-nose single-flute cutters, 12-29 Feed trips and stops, 10-5to 10-7 three- and four-sided cutters, 12-29,12-30 Grinding engine lathe cutting Ferrous metals, 4-5, 4-6 tools, 6-19 to 6-21 alloy steels, 4-6 grinding tools for roughingcuts, 6-20, 6-21 cast iron, 4-5 pig iron, 4-5 steps in grinding a tool bit, 6-20 Grinding handtools and drills, 6-25 plain carbon steels, 4-5, 4-6 wrought iron, 4-5 Grinding machines, precision, 13-1to 13-24 Grinding wheels, 6-2 to 6-10 Finishing, surface, 14-8 to 14-12 diamond wheels, 6-6 Fits, classes of, 3-32 to 3-34 grain depth of cut, 6-6, 6-7 Fixed gages, 2-11 to 2-18 grinding wheel selection anduse, 6-7 to 6-9 depth micrometer, 2-18 sizes and shapes, 6-3 graduated gages, 2:-1 1 to 2 14 truing and dressing the wheel, inside micrometer, 2-17, 2-18 6-10 micrometers, 2-16 wheel installation, 6-9, 6-10 wheel markings and composition,6-3 to miscellaneous micrometers, 2-18 6-6 nongraduated gages, 2-14 to 2-16 outside micrometer, 2-17 Grooving and parting, 8-20to 8-23 . thread micrometer, 2-18 Ground-in chip breakers, 6-14,6-15 Flow chart, drafta 14-54 Flutes and keyseats, slotting,parting, and milling, H 11-46 to 11-57 Fly cutting, 11-56, 11-57 Hacksaws, power, 5-1 to 5-3 Follower rest and center rest, using, 8-14, 8-15 blade selection, 5-2, 5-3 Follower rest, lathe, 7-23 coolant, 5-3 Formal schools, 1-3 feeds and speeds, 5-3 Formed cutters, 13-21, 13-22 operation, 5-3 Formulas for spur gearing, All -1to All -3 Hand reaming, 3-24 to 3-26 Four-jaw independent chuck, 8-10, 8-11 Hand taps and dies, 3-26to 3-31 INDEX

Handtools and drills, grinding, 6-25 Indexing equipment, 11-7 to 11-10 Hardenability, metals, 4-2 dividing head, 11-7 to 11-9 Hardening, 4-20, 4-21 gearing arrangement, 11-9, 11-10 Hardness, metals, 4-2 Indexing the work, 11-12 to 11-20 Hardness tests, 421 to 4-25 angular indexing, 11-15 to 11-16 Brinell, 4-24 compound indexing, 11-16, 11-17 Rockwell, 4-22 to 4-24 differential indexing, 11-17 to 11-20 sclerosct.pe, 4-24, 4-25 direct indexing, 11-12, 11-13 Vickers, 4-25 plain indexing, 11-13 to 11-15 Headstock, 7-4, 7-5, 10-3 to 10-5 Information, sources of, 1-7, 1-8 Heat resistance, metals, 4-3 Heat treatment, 4-19 to 4-21 Inside micrometer, 2-17, 2-18 annealing, 4-19, 4-20 Internal groove gage, 2-8 case hardening, 4-21 hardening, 4-20, 4-21 normalizing, 4-20 K tempering, 4-21 Helical teeth (plain milling cutters), 13-15, 13-16 High-pressure steam valves, assembling, 15-27, Keyseats and flutes, slotting, parting, and mill- 15-28 ing, 11-47 to 11-57 High-speed steel, 6-15 Keyseats and keys, 3-44 to 3-46 High-speed universal attachment, 11-58 Knee and column milling machines, 11-1 to 11-6 Holding the work, methods, of, 8-6 to 8-15 major components, 11-3 to 11-6 between centers, 8-6 to 8-8 care of chucks, 8-12 Knee, toolmaker's, 11-61 in chucks, 8-10 to 8-12 Knurling, 8-23 to 8-26 on a faceplate, 8-12, 8-13 on a mandrel, 8-8 to 8-10 on the carriage, 8-13 using the center rest and follower rest, 8-14, 8-15 Hones and honing, 13-22 Labels and tags, calibration servicing, 15-42 to 15-45 Horizontal boring mill, 11-64 to 11-72 boring mill operations, 11-69 to 11-72 Lathe operations, basic engine, 8-1 to 8-26 combination boring and facing head, 11-67 Lathes and attachments, 7-1 to 7-27 to 11-69 attachments and accessories, 7-15 to 7-27 right angle milling attachment, 11-69 carriage stop, 7-24, 7-25 Horizontal turret lathes, 10-1 to 10-8 center rest, 7-22, 7-23 clrsification of, 10-2, 10-3 follower rest, 7-23 cG,nponents, 10-3 to 10-8 grinding attachment, 7-25 Hydraulic and arbor presses, 3-34, 3-35 lathe centers, 7-21, 7-22 lathe chucks, 7-18 to 7-21 lathe dogs, 7-22 I milling attachment, 7-25 other types of lathes, 7-26, 7-27 taper attachment, 7-23, 7-24 Identification of metals, 4-13 to 4-19 thread dial indicator, 7-24 acid test, 418 419 toolholders, 7-16 to 7-18 spark test, 4-14 to 4-18 toolposts, 7-16 Idler gears, 7-10 to 7-12 tracing attachments, 7-25, 7-26 MACHINERY REPAIRMAN 3 & 2

Lathes and attachmentsContinued Marking of metals, standard, 4-13 engine lathe, 7-1 to 7-15 Masking, 14-41 apron, 7-7, 7-8 Measuring gages, shop, 2-5 to 2-21 bed and ways, 7-1 to 7-4 Measuring screw threads, 9-15, 9-16 carriage, 7-6, 7-7 Mechanical drawings and blueprints,3-1 to 3-10 compound rest, 7-15 common blueprint symbols, 3-2 to 3-8 feed rod, 7-8, 7-9 limits of accuracy, 3-9, 3-10 gearing, 7-9 to 7-15 units of measurement, 3-8, 3-9 headstock, 7-4, 7-5 working from drawings, 3-2 lead screw, 7-9 Metal buildup 14-1 to 14-67 tailstock, 7-5, 7-6 contact electroplating, 14-12 to 14-25 Layout and benchwork, 3-1to 3-48 final preparation, 14-53 to 14-57 benchwork, 3-22 to 3-48 masking, 14-41 assembly and disassembly, 3-23 plating tool covers, 14-35 to 14-37 fastening devices, 3-40 to 3-48 plating toolsselection and preparation, precision work, 3-23 to 3-38 14-27 to 14-35 safety: oxyacetylene equipment, power pack components, 14-25 to 14-27 3-38 to 3-40 preparation instruction: general, 14-57to layout, 3-10 to 3-22 14-59 materialvand equipment, 3-11, preparation of anodes for the electroplat- 3-12 ing process, 14-38 to 14-40 methods, 3-12 to 3-22 preplate instructions, 14-60, 14-61 mechanical drawings and blueprints,3-1to selection of power pack, 14-27 3-10 setting up joblongerrange preparations, common blueprint symbols, 3.2 to 14-42 to 14-53 3-8 storage and shelf life of solutions, 14-41 limits of accuracy, 3-9, 3-10 summary of electroplating, 14-62, 14-63 units of measurement, 3-8, 3-9 thermal spray systems, 14-1 to 14-12 working from drawings, 3-2 troubleshooting, 14-63 to 14-67 Lead alloys, 4-8 verifying identity of base material, 14-59, 14-60 Lead screw, 7-9 Metal cutting bandsaws, 5-5 to 5-18 Left-hand screw 9-22, 9-23 sawing operations, 5-16 to 5-18 selection of saw bands, speeds andfeeds, 5-10 to 5-13 sizing, splicing, and installing bands, 5-13 to 5-16 terminology, 5-6 to 5-10 Machine shop maintenance, 15-31to 15-33 Metal disintegrators, 5-31 to 5-33 Machinability, metals, 4-3 Metals, 4-3 to 4-8 Machining and grinding, 14-65 ferrous, 4-5, 4-6 Machining operations, 8-15 to 8-20 nonferrous, 4-6 to 4-8 cutting speeds and feeds, 8-15 to 8-18 Metals and plastics, 4-1 to 4-31 facing, 8-18 designations and markings of metals, 4-8to planning the job, 8-15 4-13 turning, 8-18 to 8-20 hardness tests, 4-21 to 4-25 heat treatment, 4-19 to 4-21 Magnetic chucks, 13-5, 13-6 identification of metals, 4-13 to 4-19 Maintenance, machine shop, 15-31to 15-33 metals, 4-3 to 4-8 Malleability, metals, 4-2 plastics, 4-25 to 4-31 Mandrel, holding work op a,3 t... 8-10 properties of metals, 4-1 to 4-3 Manufacturers' technical 1-7, 1-8 standard marking of metals, 4-13 '-r INDEX

Micrometers, 2-16 Offhand grinding of toolsContinued Micrometer, thread, 9-16 chip breaker grinder, 6-12 to 6-14 Milling attachment, lathe, 7-25 cutting tool materials, 6-15 Milling machines and milling operations, 11-1to 11-73 grinding engine lathe cutting tools, 6-19 cutters and arbors, 11-20 to 11-35 to 6-21 feeds, speeds, and coolants, 11-61 to grinding handtools and drills, 6-25 11-64 grinding safety, 6-1, 6-2 horizontal boring mill, 11-64 to 11-72 indexing the work, 11-12 to 11-20 grinding wheels, 6-2 to 6-10 knee and column milling machines, 11-1 to ground-in chip breake,s, 6-14, 6-15 11-6 high-speed steel, 6-,3 milling machine attachments, 11-58 to 11-61 milling machine operations, 11-35 to 11-58 operation of the carbide tool grinder, 6-11, safety precautions, 11-72, 11-73 6-12 special attachments, 11-10, 1 1 -1 1 shaper and planer tools, 6-23 to 6-25 workholding devices, 11-6 to 11-10 turret lathe tools, 6-21 to 6-23 MIRCS labels, 15-45 wheel care and storage, 6-25 wheel selection, 6-11 Multiple screw threads, 9-23 to 9-25 On-the-job training, 1-3, 1-4 Operation of the carbide tool grinder, 6-11, 6-12 N Operations, shaper, 12-7 to 12-13 angular surfaces, shaping, 12-10 feeds and speeds, 12-7 to 12-9 NAVSEA publications, 1-7 internal keyway, shaping on, 12-11, 12-12 Nickel alloys, 4-7, 4-8 irregular surfaces, shaping, 12-12, 12-13 Nonferrous metals, 4-6 to 4-8 keyways in shafts, shaping, 12-10, 12-11 aluminum alloys, 4-8 rectangular block, shaping, 12-9, 12-10 copper alloys, 4-7 lead alloys, 4-8 Operations, turret lathe, 10-8 to 10-25 nickel alloys, 4-7, 4-8 boring, 10-19 to 10-25 tin alloys, 4-8 horizontal turret lathe type work, 10-25 zinc alloys, 4-8 tooling horizontal turret lathes, 10-8 to 10-19 Nongraduated gages, 2-14 to 2-16 Nonresident career courses and rate training Organization and personnel, repair department, manuals, 1-3 15-1 to 15-5 assistant repair officer, 15-4, 15-5 Normalizing, 4-20 division officers, 15-5 enlisted personnel, 15-5 repair officer, 15-2 to 15-4 0 Outside micrometers, 2-17 Oxyacetylene equipment, 3-35 to 3-38 Offcenter starts, correcting, 5-26, 5-27 Offhand grinding of tools, 6-1 to 6-25 bench and pedestal grinders, 6-2 carbide tool grinder, 6-10, 6-11 carbon tool steel. 6-15 cast alloys, 6-16 Packing, 3-47, 3-48 cemented carbide, 6-16 to 6-19 Parting, 11-47

1-7 5 ;/) MACHINERY REPAIRMAN 3 & 2

Parting and grooving, 8-20 to 8-23 Power saws and drilling machines, 5-1 boring, 8-22, 8-23 to 5-33 continuous feed cutoff saw, 5-4, 5-5 drilling and reaming, 8-21, 8-22 drilling angular holes, 5-28 to 5-31 Pantographs, 12-18 to 12-33 drilling machines and drills, 5-18 to 5-28 attachments, 12-30 to 12-32 metal cutting bandsaws, 5-5 to 5-18 cutter speeds, 1 2-22 metal disintegrators, 5-3 1 to 5-33 engraver units, 12-18 to 12-21 power hacksaws, 5-1 to 5-3 engraving a dial face, 12 -32, 12-33 power saw safety precautions, 5-1 engraving a graduated collar, 12-32 Precision grinding machines, 13-1 to 13-24 grinding cutters, 12-22 to 12-30 cutter sharpening setups, 13-15 to 13-22 setting copy, 12-21 cylindrical grinder, 13-8 to 13-10 setting the pantograph, 12-21, 12-22 hones and honing, 13-22 using a circular copy plate, 12-32 portable honing equipment, 13-22, 13-23 Pedestal and bench grinders, 6-2 setting the clearance angle, 13-13 to 13-15 speeds, feeds, and coolants, 13-1 to 13-4 Personnel and organization, repairdepartment, stationary honing equipment, 13-23 15-1 to 15-5 stone removal, 13-24 Pig iron, 4-5 stone selection, 13-23, 13-24 Pins, 3-46, 3-47 surface grinder, 13-4 to 13-8 tool and cutter grinder, 13-10 to 13-13 Pipe threads 9-14 Precision work, 3-23 to 3-38 Piston rings, making, 15-36, 15-37 broaching, 3-26 Plain carbon steels, 4-5, 4-6 classes of fits, 3-32 to 3-34 Plain indexing, 11-13 to 11-15 hand reaming, 3-24 to 3-26 Plain milling, 11-36, 11-37 hand taps and dies, 3-26 to 3-31 Plain milling cutters (helical teeth), 13-15,13-16 hydraulic and arbor presses, 3-34, 3-35 Planer and shaper tools, 6-23 to 6-25 oxyacetylene equipment, 3-35 to 3 -38 Planers, 12-14 to 12-18 removal of burrs and sharp edges, 3-24 construction and maintenance, 12-14 removing broken taps, 3-31, 3-32 operating the planer, 12-14 to 12-17 scraping, 3-23, 3-24 surface grinding, 12-17, 12-18 Preparation of anodes for the electroplating types of, 12-14 process, 14-38 to 14-40 Planned Maintenance System,purposes, Preplate instructions, 14-60, 14-61 benefits, and limitations of, 1-6, 1-7 Pressure seal bonnet globe valves, 15-27 Properties of metals, 4-1 to 4-3 Plasticity, rstst 4-2 brittleness, 4-2 Plastics, 4-": , 4-31 corrosion resistance, 4-3 chars h.:ics, 4-25 to 4-30 ductility, 4-2 macl verations, 4-30, 4-31 elasticity, 4-2 major groups, 4-30 fatigue, 4-3 Plating, 14-59 hardenability, 4-2 hardness, 4-2 Plating tools, 14-14, 14-15, 14-27 to 14-37 heat resistance, 4-3 covers, 14-35 to 14-37 machinability, 4-3 selection and preparation, 14-27 to 14-35 malleability, 4-2 Plug and ring gages, 9-16 to 9-25 plasticity, 4-2 Portable honing equipment, 13-22, 13-23 strain, 4-1 strength, 4-1, 4-2 Power oxygen-fuel spray, 14-3, 14-4 stress, 4-1 Power pack, 14-13, 14-14, 14-25to 14-27 toughness, 4-2 components, 14-25 to 14-27 weldability, 4-3 selection of, 14-27 Pumps, repairing, 15-29 to 15-31

1-8 C) INDEX

Q S

Quality assurance, 1541 to 15-45 Safety, 1-4 to 1-6 calibration servicing labels and tags, Safety, grinding, 6-1, 6-2 15-42 to 15-45 Safety precautions, milling machinz,11-72, Quality control, 14-23 to 14-25 11-73 Quick-change gear mechanism, 7-12 to 7-15 Saw bands, speeds, and feeds, selection of,5-10 to 5-13 band speeds, 5-12, 5-13 R band width and gage, 5-12 feeds, 5-13 tooth pitch, 5-12 Reamer flutes, 11-54 to 11-56 Reaming, 5-27, 5-28 Sawing operations, 5-16 to 5-18 Reaming, and drilling, 8-21, 8-22, 11-57 angular cutting, 5-16 Removal, stone, 13-24 contour cutting, 5-16, 5-17 Removing broken bolts and studs, 15-33to 15-36 disk cutting, 5-17, 5-18 Repair department and repair work,the, 15-1 to filing and polishing, 5-18 15-45 general rules, 5-16 machine shop maintenance, 15-31to 15-33 inside cutting, 5-17 making piston rings, 15-36, 15-37 straight cuts with power feed, 5-16 organization and personnel, 15-1 to 15-5 Schools, formal, 1-3 quality assurance, 15-41 to 15-45 Scleroscope hardness test, 4-24, 4-25 removing broken bolts and studs,15-33 to Scope of the Machinery Repairman rating,1-1 I.-36 to 1-8 repair work, 15-7 to 15-31 addendum, 1-8 shops, 15-5 to 15-7 on-the-job training, 1-3, 1-4 spring winding, 15-37 to 15-41 other training manuals, 1-4 Repair work, 15-7 to 15-31 purposes, benefits, and limitations of the gears, 15-8 to 15-14 Planned Maintenance System, 1-6, 1-7 pumps, 15-29 to 15-31 rate training manuals and nonresidentcareer shafts, 15-14 to 15-16 courses, 1-3 valves, 15-16 to 15-29 safety, 1-4 to 1-6 sources of information, 1-7, 1-8 Rack milling attachment, 11-59 training, 1-2, 1 -3 Raising block, 11-59 to 11-61 typical assignments and duties, 1-2 Rate training manuals and nonresidentcareer courses, 1-3 Screw thread inserts, 3-42 to 3-44 Ring and plug gages, 9-16 to 9-25 Screw threads, 9-8 to 9-13 iiow to cut screw threadson a lathe, 9-18 other forms of, 9-11 to 9-13 to 9-22 V-form, 9-10, 9-11 left-hand screw threads, 9-22, 9-23 Seals, 3-48 multiple screw threads, 9-23 to 9-25 Setting the clearance angle, 13-13to 13-15 threads on tapered work, 9-25 Setting up joblongerrange preparations, 14-42 three wire method, 9-16 to 9-18 to 14-53 Setting up the lathe, 8-2 to 8-6 Right angle milling attachment, 11-69 preparing the centers, 8-3 to 8-5 Right angle plate, 11-59 setting the toolholder and cutting tool, Rockwell hardness test, 4-22 to 1-24 8-5, 8-6 Roughening, surface, 14-6, 14-7 Shafts, 15-14 to 15-16 Rubber flex collet chuck, 8-12 Shaper and planer tools, 6-23 to 6-25 1-95si MACHINERY REPAIRMAN 3 & 2

Shapers, planers, and engravers, 12-1to 12-33 Spark test, 4-14 to 4-18 pantographs, 12-18 to 12-33 Speeds, 11-61, 11-62 attachments, 12-30 to 12-32 Speeds, feeds, and coolants, 13-1 to 13-4 cutter speeds, 12-22 coolants, 13-3, 13-4 engraver units, 12-18 to i 2-21 depth of cut, 13-2, 13-3 engraving a dial face, 12 -32, 12-33 traverse (work speed), 13-2 engraving a graduated collar, 12-32 wheel speeds, 13-1, 13-2 grinding cutters, 12-22 to 12-30 Spotfacing, counterboring, and countersinking, setting copy, 12-21 5-27 setting the pantograph, 12-21, Spring winding, 15-37 to 15-41 12-22 tables for, 15-37 to 15-41 using a circular copy plate, 12 -32 Spur gearing, formulas for, All -1 to All -3 planers, 12-14 to 12-18 Spur gear terminology, 15-9 to 15-11 construction and maintenance, Staggered tooth cutters, 13-17, 13-18 12-14 Stationary honing equipment, 13-23 operating thet.finer, 12-14 to Stone removal, 13-24 12-17 Stone selection, 13=13, 13-24 surface grinding, 12-17, 12-18 Storage and shelf life of solutions, 14-41 types of, 12-14 Straight external keyseats, 11-48 to 11-50 shapers, 12-1 to 12-13 Straight flutes, 11-53 assemblies, 12-1 to 12-4 Straight pipe threads, 9-14 operations, 12-7 to 12-13 Strain, metals, 4-1 safety precautions, 12-6, 12-7 Strength, metals, 4-1, 4-2 toolholders, 12-5, 12-6 Stress, metals, 4-1 types of, 12-1 Surface gage, 2-10, 2-11 vise, 12-4, 12-5 Surface grinder, 13-4 to 13-8 vertical shapers, 12-13, 12-14 cross traverse table, 13-4, 13-5 Sharpening setups, cutter, 13-15 to 13-22 sliding table, 13-5 Shop measuring gages, 2-5 to 2-21 using the, 13-7, 13-8 adjustable gages, 2-5 to 2-11 wheelhead, 13-5 care and maintenance of gages, 2-19 to 2-21 workholding devices, 13 -S to 13-7 fixed gages, 2-11 to 2-18 Surface grinding on the planer, 12-17, 12-18 Shops, repair department, 15-5 to 15-7 Shoulder stud job, 10-25 Side milling cutters, 13-16 Sizing, splicing, and installing bands, 5-13to 5-16 Sliding table, 13-5, 13-8, 13-9 cylindrical grinder, 13-8, 13-9 Tabular Information of Benefit to Machinery surface grinder, 13-5 Repairman, Al-1 to AI -25 Slotting attachment, milling machine, 11-10, Tags and labels calibration servicing, 15-42 11-11 to 15-45 Slotting, parting, and milling keyseatsand flutes, Tailstock, 7-5, 7-6 11-46 to 11-57 Taper attachment, lathe, 7-23, 7-24 external keyseat, 11-47, 11-48 Tapered pipe threads, 9-14 fly cutting, 11-56, 11-57 Tapered stud job, 10-25 parting, 11-47 Tapers, 9-1 to 9-8 reamer flutes, 11-54 to 11-56 boring, 9-6 to 9-8 slotting, 11-46, 11-47 methods of turning, 9-3 to 9-6 straight external keyseats, 11-48 to 11-50 Taper turning on a vertical turret lathe, 10-30to straight flutes, 11-53 10-32 tap flutes, 11-53, 11-54 Tap flutes, 11-53, 11-54 Woodruff keyseat, 11-50 to 11-53 Tapping, 5-28

I-10 0 L. 4,t) INDEX

Tempering, 4-21 Turning, 8-18 to 8-20 Terminology, contact electroplating, 14-17to finish turning, 8-19, 8-20 14-21 rough turning, 8-19 Terminology, spur gear, 15-9 to 15-11 to a shoulder, 8-20 Thermal spray systems, 14-1 to 14-12 application of coating, 14-7, 14-8 Troubleshooting, 14-63 to 14-67 approved applications, 14-1, 14-2 formulas, 14-65 to 14-67 power oxygen-fuel spray, 14-3, 14-4 low thickness deposit, 14-64 preparing the surface, 14-4, 14-5 machining and grinding, 14-65 qualification of personnel, 14-2 nonuniform thickness of deposit, 14-64 safety precautions, 14-2 poor adhesion, 14-63, 14-64 surface finishing, 14-8 to 14-12 poor deposit quality, 14-64 surface roughening, 14-6, 14-7 tool too long to finish job, 14-64 undercutting, 14-5, 14-6 Turning tapers, method of, 9-3 to 9-6 wire oxygen spray, 14-2 Turret lathes and turret lathe operations,10-1 to Thread dial indicator, 7-24 10-32 Threaded fastening devices, 3-40to 3-42 horizontal turret lathes, 10-1 to 10-8 Threading mechanism, 10-7, 10-8 classification of, 10-2, 10-3 Thread micrometer, 2-18, 9-16 components, 10-3 to 10-8 Three-jaw universal chuck, 8-11, 8-12 operations, 10-8 to 10-25 Tin alloys, 4-8 boring, 10-19 to 10-25 Tool andutter grinder, 13-10to 13-13 horizontal turret lathe type cutter sharpening, 13-11 to 13-13 work, 10-25 wheelhead, 13-11 tooling horizontal turret lathes, workhead, 13-11 10-8 to 10-19 Toolholder and cutting tool, setting, 8-5,8-6 safety, 10-1 Toolholders, 7-16 to 7-18 vertical turret lathes, 10-25 to 10-32 Toolholders, shaper, 12-5, 12-6 taper turning, 10-30 to 10-32 Tooling, 10-8 to 10-19, 10-28 to 10-30 tooling, 10-28 to 10-30 horizontal turret lathes, 10-8 to 10-19 Turret lathe tools, 6-21 to 6-23 vertical. turret lathes, 10-25 to 10-32 Twist drill, 5-21 to 5-23 Tool issue room, 2-1 to 2-5 Toolmaker's knee, 11-61 Toolposts, 7-16 U Toolpost grinder, settingup the, 8-24 to 8-26 Toolrooms and tools, 2-1 to 2-21 shop measuring gages, 2-5 to 2-21 Undercutting, 14-5, 14-6 adjustable gages, 2-5 to 2-11 care and maintenance of gages, Universal bevel, 2-8 2 -19 to 2-21 Universal vernier bevel protracter, 2-8 fixed gages, 2-11 to 2-18 Universal vise, 13-6, 13-7 tool issue room, 2-1 to 2-5 control of tools, 2-4 organization of the toolroom, 2-1 V to 2-4 safety in the toolroom and the shop, 2-4, 2-5 Verifying identity of base material, 14-59,14-60 Toughness, metals, 4-2 Vernier caliper, 2-6, 2-7 Tracing attachments, lathe, 7-25, 7-26 Vernier height gage, 2-7, 2-8 Training, 1-2, 1-3 Vertical milling attachment, 11-58 Traverse (work speed), 13-2 Vertical shapers, 12-13, 12-14

Ill 51/45,3 MACHINERY REPAIRMAN3 & 2

Vertical turret lathes, 10-25 to 10-32 Wheel selection, 6-11 taper turning, 10-30 to 10-32 Wheel speeds, 13-1, 13-2 tooling, 10-28 to 10-30 Winding, spring, 15-37 to 15-41 Vickers hardness test, 4-25 Wire oxygen spray, 14-2 Vises, 11-7 Woodruff keyseat, 11-50 to 11-53 Vise, shaper, 12-4, 12-5 Workhead, tool and cutter grinder, 13-11 Workholding devices, 11-6 to 11-10 indexing equipment, 11-7 to 11-10 vises, 11-7 Workholding devices, surface grinder, 13-5 to 13-7 Ways and bed, 7-1 to 7-4 Weldability, metals, 4-3 Work speed (traverse), 13-2 Wheel care and storage, 6-25 Wrought iron, 4-5 Wheelhead, 13-5, 13-9, 13-11 cylindrical grinder, 13-9 surface grinder, 13-5 tool and cutter grinder, 13-11 Zinc alloys, 4-8 MACHINERY REPAIRMAN3&2 NAVEDTRA 10530-E

Prepared by the Naval Education and TrainingProgram Development Center, Pensacola, Florida

Your NRCC contains a set of assignments and designated to grade it. The graded perforated answer sheets. The Rate answer sheet Training Man- will not be returned to you. ual, Machinery Repairman 30

NAVEDTRA 10530-E , is your textbook for the If you are completing this NRCC tobecome NRCC. If an errata sheet comes with theNRCC, eligible to take the fleetwide advancementexam- make all indicated changesor corrections. Do not ination, follow a schedule that will enableyou change or correct the textbook or assignmentsin any other way. to complete all assignments in time. Yoursched- ule should call for the completion ofat least one assignment per month. HOW TO COMPLETE THIS COURSE Although you complete the coursesuccess- SUCCESSFULLY fully, the Naval Education and Training Program Development Center will not issueyou a letter Study the textbook pages given at the begin- of satisfactory completion. Your commandwill ning of each assignment before tryingto answer make an entry in your service record, givingyou the items. Pay attention to tables and illustra- credit for your work. tions as they contain a lot of information. Making your own drawings can helpyou understand the subject matter. Also, read the learningob- jectives that precede the sets of items. WHEN YOUR COURSE IS ADMINISTERED The BY THE NAVAL EDUCATION learning objectives and itemsare based on the subject matter or study material in the AND TRAINING PROGRAM textbook. DEVELOPMENT CENTER The objectives tell you what you should beable to do by studying assigned textual materialand answering the items. After finishing an assignment,go on to the next. Retain each completed At this point you should be ready to answer sheet until answer you finish all the assignments in the items in the assignment. Read each a unit (or in item care- the course if it is not divided fully. Select the BEST ANSWER for each into units). item, Using the envelopes provided, mail consulting your textbook when your com- necessary. Be sure pleted answer sheets to the Naval to select the BEST ANSWER from the subject Education and matter Training Program Development Center in the textbook. You may discuss difficult where they points will be graded and the in the course with others. However, score recorded. Make sure the answer all blanks at the top of each you select must be your own. Remove a perforated answer sheet are filled in. Unlessyou furnish all the informa- answer sheet from the back of this text, write tion required, it will be impossible in the proper assignment number, and to give you enter your credit for your work. The graded answer for each item. answer sheets will not be returned.

Your NRCC will be administered byyour com- mand or, in the case of small commands,by the The Naval Education and TrainingProgram Naval Education and Training Program Development Development Center will issuea letter of satis- Center. No matter who administersyour course factory completion to certifysuccessful comple- tion of the course (or you can complete it successfully by earninga 3.2 a creditable unit of the course). To receive for each assignment. The unit breakdown ofthe a course-completion letter, course, if any, is shown later under Naval follow the directions givenon the course-com- Reserve Retirement Credit. pletion form in the back of thisNRCC.

You may keep the textbook andassignments WHEN YOUR COURSE IS ADMINISTERED for this course. Return them BY LOCAL COMMAND only in the event you disenroll from the courseor otherwise fail to complete the course. Directionsfor returning As soon as you have finishedan assignment, the textbook and assignmentsare given on the submit the completed answer sheet to the officer book-return form in the backof this NRCC.

5 PREPARING FOR YOUR ADVANCEMENT COURSE OBJECTIVE EXAMINATION

Your examination for advancement is based This course provides knowledge that on the Occupational Standards for your rating as will help you develop your skills inthe found in the MANUL OF NAVY ENLISTED MANPOWER following areas: AND PERSONNECULASSIFICATIONS AND OCCUPATIONAL STANDARDS (NAVPERS 18068). These OccupiffEgT- Use and care of precision handtools, 3Eirialai define the minimum tasksrequired of managing a toolroom, layout of parts, your rating. The sources of quest ons in your general bench work, working with metals advancement examination are listed in the BIBLI- and plastics and basic metallurgy. OGRAPHY FOR ADVANCEMENT STUDY (NAVEDTRA 10052). For convenience, the Occupational Standards use and care of shop equipment and the sources of questions foryour rating are including power saws, band saws, drill combined in a single pamphlet for the series of presses, grinders, engine lathes, turret examinations for each year. These OCCUPATIONAL lathes, milling machines:shapers, STANDARDS AND BIBLIOGRAPHY SHEETS (calledBib planers, engravers, metal plating equip- Sheets), are available from your ESO. Sinceyour ment, and tool and cutter grinders. textbook and NRCC are among thesources listed in the bibliography, be sure to study bothas Shop work, including grinding of you take the course. The qualifications for your lathe and shaper tool bits, cuttingspur rating may have changed since your course and gears, turning shafts, metal buildup, textbook were printed, so refer to the latest and machining various parts. edition of the Bib Sheets. The organization of a shipboard repair department and planning and NAVAL RESERVE RETIREMENT CREDIT organizing shop work.

This course is evaluated at 22 Naval Reserve Retirement points. These points are creditable to personnel eligible to receive them under current directives governing retirem'at of Naval Reserve personnel. Points will be credited in unitsas follows:

Unit 1: 12 points upon satisfactory comple- tion of AssiRnmen's lthrough 6.

Unit 2: 10 points upon satisfactory comple- tion of Assignments 7 through 11.

While working on this correspondence course, you may refer freely to the text. You may seek advice and instructionfrom others on problems arising in thecourse, but the solutions submitted must be the result of your own work and decisions. You are prohibited from referring toor copying the solutions of others,or giving completed solutions to anyone else taking the same course.

ii Naval courses may include a variety of questions-- multiple-choice, true-false, matching, etc. The questions are not grouped by type; regardless of type, theyare presented in the same general sequence as the textbook material upon which they are based. This presentation is designed to pre- serve cintinuity of thought, permitting step-by-step development of ideas. Some courses use many types of questions, others only a few. The student can rear "'' identify the type of each question (and the action required) through inspection of the samp' ;:v,..1 below.

MULTIPLE-CHOICE QUES!

Each question contains several alternatives, one of which provides the bestanswer to the question. Select the best alternative, and blacken the appropriate boxon the answer sheet.

SAMPLE

s-1. The first person to be appointed Secretary Indicate in this way on the answer sheet: of Defense under the National Security Act of 1947 was 1. George Marshall 1 2 3 4 2. James Forrestal 3. Chester Nimitz 4. William Halsey

TRUE-FALSE QUESTIONS

Mark each statement true or false as indicated below. If any part of the statement is false the statement is to be considered false. Make the decision, and blacken the appropriate box on the answer sheet.

SAMPLE

s-2. Any naval officer is authorized to corres- Indicate in this way on the answer sheet: pond officially with any systems command of the Department of the Navy without his

commanding officer's endorsement. 1 2 3 4

s-2

MATCHING QUESTIONS

Each set of questions consists of two columns, each listing words, phrasesor sentences. The task is to select the it in column B which is the best match for the item in column A that is being considered. Items in column B may be used once, more than once, or not at all. Specific instructions are given with each set of questions. Select the numbers identifying the answers and blacken the appropriate boxes on the answer sheet.

SAMPLE

In questions s-3 through s-6, match the name of the shipboard officerin column A by selecting from column B the name of the department in which the officer functions.

A B Indicate in this wayon the answer sheet:

s-3. Damage Control Assistant 1. Operations Department 1 .2 3 4 s-4. CIC Officer 2. Engineering Department s-3 LI s-5. Disbursing Officer 3. Supply Department s-4 s-6. Communications Officer s-5 s-6 00

iii

5L'LI Assignment 1 Scope of the Machinery Repairman Rating; Toolrooms and Tools4 Layout and Benchwork

Textbook Assignment: Pages 1-1 through 3-18

In this course you will demonstrate that learning has taken place by correctly answering training items. The mere physical act of indicating a choice on an answer sheet isnot in itself important; it is the mental achievement, in whatever form it may take, priorto the physical act that is important and toward which course learning objectives are directed. The selection of the correct choice for a course training item indicates that you have fulfilled, at least inpart, the stated objective(s).

The accomplishment of certain objectives, for example, a physical act suchas drafting a memo, cannot readily be determined by means of objective type course items; however,you can demonstrate by means of answers to training items that you have acquired the requisiteknowledge to perform the physical act. The accomplishment of certain other learning objectives, for example, the mental acts of comparing, recognizing, evaluating, choosing, selecting,etc., may be readily demonstrated in a course by indicating the correctanswers to training items.

The comprehensi-e objective for this course has already been given. It states the purpose of the course in terms of what you will be able to do as you complete thecourse.

The detailed objectives in each assignment state what you should accomplishas you progress through the course. They may appear singly or in clusters of closely related objectives,as appropriate; they are followed by items which will enable you to indicateyour accomplishment.

All objectives in this course are learning objectives and items are teaching items. They point out important things, they assist in learning, and they should enableyou to do a better job for the Navy.

This self-study course is only one part of the total Navy training program; by itsvery nature it can take you only part of the way to a training goal. Practical experience, schools, selected reading, and the desire to accomplish are also neceFsary to round outa fully meaningful training program.

1-4. The courses that are mandatory to meet Learning Objective: Identify the advancement requirements are listed in Machinery Repairman rating, listing what publication(s)? the sources of training, information, 1. BUPERSINST 1430.16 and overview functions of the rating. 2. NAVSEA publications Textbook pages 1-1,through 1-8. 3. NAVPERS 10530E 4. NAVEDTRA 10194-C

1-1. Machinery Repairmen always work in 1-5. The Bibliography for Advancement Study, machine shops which are fully equipped NAVEDTRA 10052, is revised annually. and have all the associated machinery. 1-6. Preventive maintenance reduces the need 1-2. Which of the following types of training for major corrective maintenance. is/are provided by the machinery repair- man class "A" school? 1-7. By what procedure is the Naval Ships' 1. Classroom theory Technical Manual kept up-to-date? 2. Hands on experience 1. Annual changes *. Project procedures 2. Quarterly changes 4. All of the above 3. Monthly changes 4. Changes when revised 1-3. By what training system is the heat treatment of metals taught? 1. "A" school. 2. On -job- training 3. Self- taught 4, "C" school

1 1-8. In what order are the drawings listed in 1-14. Which of the following is a good practice the Ship Drawing Index (SDI)? for a toolroom keeper to follow? 1. Alphabetical order 1. Check the accuracy of precision tools 2. Numerical order before issuing them and again after 3. By ship'e hull number they are returned 4. By compartment numbers 2. Repair damaged tools immediately after they are returned to the toolroom 3. Remove all oil and foreign matter from Learning Objective: Identify the tools returned to the storeroom and duties/responsibilities of a toolroom store them dry keeper and the characteristics of a 4. Sharpen all cutting tools before properly organized toolroom. Textbook placing them in their storage spaces pages 2-1 through 2-4. 1-15. What recommended procedure should a storeroom keeper use as a means of con- 1-9. Normally, which of the following functions trolling tools loaned to all departments is NOT a duty of the toolroom keeper? on a ship? 1. Controlling the custody of tools 1. Provide a checkout log at the issuing 2. Testing metal for hardness window and require the borrower to 3. Storing measuring instruments properly sign his name and list the tool 4. Replacing broken hammer handles borrowed 2. Issue numbered tool checks to all 1-10. Which of the following provisions is NOT departments; when a department borrows normally required in a toolroom ashore, a tool, it surrenders a tool check to but should be provided in a shipboard the toolroom keeper toolroom? 3. Maintain a columnar checkout board with 1. Cushions for reducing damage to tools a separate column for each department; 2. Fasteners for holding tools in place when a tool is issued, its name is 3. Special bins for storing power tools recorded in the proper column on the 4. Replacement parts for repairing board broken tools 4. Use checkout slips or formson which are recorded the borrower's name, 0 For items 1-11 through 1-14, assume that name of the tool and its location, you have the following storage spaces in and the date your toolrooms onboard ship: A. Metal shelves 1-16. If maintaining a custody record of tools B. Metal rotating bins issued fails to provide you with adequate C. Lined wooden boxes control of the tools, what additional D. Metal cabinet with various sized measures should you take to make your drawers control of tools more effective? E. Wooden wall rack 3 feet wide, extend- 1. Take a periodic physical count of each ing to the overhead, and equipped with tool and each item of supply spring-loaded fasteners 2. Require each department to submit a list of tools and supplies in its 1-11. Where should the cutter illustrated in possession at the end of each week figure 2-12 in the textbook be stored? 3. Require departments to turn in tools 1. On A at the end of each working day 2. In C 4. Co to each department at least once a 3. In D month and check the tools and supplies 4. On E in its possession against your record

1-12. Which storage space should youuse for 1-17. Aboard ship, who initially signs the a gear tooth vernier? custody card for an item listed as 1. B "controlled equipage" when it is received 2. C from the supply department? 3. D 1. User 4. E 2. Toolroom keeper 3. Division officer 1-13. Storage space B is most suitable for 4. Department head 1. wood chisels 2. hammers 1-18. Inventory of controlled equipage is 3. nuts and bolts conducted at least once each quarter. 4. small power drills

I .11J,, 2* 1-24. What method is used to determine the Learning Objective: Identify the height at which an adjustable parallel characteristics and uses of adjustable is locked? gages. Textbook pages 1-4 through 2-10. 1. A scale on the diagonal edge of one block 2. An outside micrometer measurement 1-19. Using a lathe, you are to turn a piece of 3. A feeler gage placed between the 8-inch stock down to 7 1/2 +1/64inch. ',lock and the workpiece Normally, what is the most accurate pro- 4. A direct comparison with a gage block cedure to use? 1. Measure the stock with a 6-inch rule, scribe a circle on the end of the Learning Objective: Identify the stock, and turn it down until the characteristics and uses of fixed cutting tool reaches the scribe mark gages. Textbook pages 2-11 through 2-15. 2. Set a caliper at a reading slightly greater than 7 1/2 inches and gage the workpiece at intervals during the 1-25. The steel rule with holder set is used turning operation normally for measurin 3. Set the lathe to cut to a fixed depth 1. recesses and repeat the turning operation the 2. gear teeth required number of times 3. thicknesses 4. Measure the workpiece at intervals 4. cylindrical surfaces during the turning operation withany type of gaga, and continue to cut 1-26. A one-quarter size scale that is 12 inches until reaching the desired dimension long is calibrated to read fromzero to 1. 3 in. 1-20. For what purpose is a dial indicatormost 2. 4 in. useful? 3. 36 in. 1. To locate the center of a piece of 4. 48 in. round stock 2. To check a shaft for out-of-roundness 1-27. Acme thread tool gages are usfd to 3. To true the internal surfaces ofa 1. measure the pitch of screw or bolt cylinder threads 4. To measure distances between two 2. estimate the thread angle of screws closely mated surfaces or bolts 3. set up thread-cutting tools 1-21. Standard vernier calipers have scales 4. determine clearances between bolt and graduated in what increments? nut threads 1. 0.0001 in. 2. 0.001 in. 1-28. SuppOse that a mechanism hasa bushiat 3. 0.01 in. with a 6-inch diameter and has a clearance 4. 0.1 in. of 0.001 inch between it and the mechanism housing. Which tool should you use to 1-22. To check the inside of a cylinder for check the clearance of the housing? out-of-roundness, you should use a/an 1. Feeler gage 1. master ring gage 2. 6-inch metal scale 2. dial vernier caliper 3. Cutter clearance gage 3. outside micrometer 4. Micrometer 4. dial bore gage 1-29. A rounded shoulder on a part to he 1-23. A gear tooth vernier is able to measure machined is measured with a what dimension(s)? 1. Center gage 1. One linear dimension 2. Feeler gage 2. One linear dimension and one angle 3. Surface gage simultaneously 4. Radius gage 3. Two linear dimensions simultaneously 4. Two linear dimensions and two arcs 1-30. A sine bar is used to locate very small simultaneously irregularities on a machined surface.

3 1-31. Which of the foll(..ing is an ordinaryuse 1-36. In what order should these steps to of parallel blocks? performed? 1. To check the concavity of a curved 1. B,D,F,C,A, E surface 2. B,D,F,A,C, E 2. To determine whether the opposite 3. F,D,B,A,C, E edges of a wo :kpiece are parallel 4. F,D,C,A,B, E 3. To compare workpiece dimensions with a finished piece 1-37. A cylindrical standard is used to test a 4. To accurately position work for micrometer for machining 1. incorrect positioning of the anvil 2. master gage variations 3. concave wear of the measuring faces Learning Objective: Identify the 4. distortion of the frame proper procedures for using and maintaining micrometers. Textbook 1-38. If the measuring surfaces of a micrometer pages 2-15 through 2-21. are concave, how should they be corrected? 1. By grinding 2. By lapping 1-32. Which of these measuring tools is the 1. By filing most precise for checking the accuracy 4. By facing on a lathe of a micrometer? 1. Gage block 1-39. Which of the following instruments is 2. Machinist's rule required to zero set an inside micrometer? 3. Dial indicator 1. Hollow cylindPt standard 4. Vernier caliper 2. Micrometer caliper 3. Vernier caliper 1-33. How can you determine if a micrometer 4. Cylinder gage needs to be recalibrated? 1. Ask your supervisor 1-40. To lubricate the internal parts ofa 2. Ask the supply clerk micrometer, you should use 3. Read index B in Tools and Their Uses, I. petroleum jelly NAVEDTRA 10085-B1 2. silicone grease 4. Check the tool calibration sticker 3. graphite powder 4. light oil 1-34. When using a micrometer, you should avoid all EXCEPT which of the following 1-41. A sticky or sluggish dial in a vernier practices? dial indicator can be freed by applying 1. Back the spindle away from the anvil a few drops of light machine oil. when placing it in storage 2. Measure moving parts 3. Open it by spinning the frame Learning Objective: Indicate the 4. Carry it in your pocket proper uses of blueprints and identify basic blueprint symbols. Textbook 1-35. Which of these conditions can cause a pages 3-1 through 3-7. zero adjusted micrometer to read more than zero when its spindle is in contact with the anvil? 1-42. What is a blueprint? 1. Thread wear 1. A detailed enlargement of a portion 2. Burrs on the spindle of a drawing 3. Worn anvil 2. A reduced copy of a large drawing 4. Rusted barrel 3. An original drawing 4. An exact copy of an original drawing A number of steps in adjusting a thimble 11 cap type micrometer are listed below in 1-43. You can locate your shipboard duty station scrambled order. by referring to a blueprint coned a/an A. Rotate the thimble to zero 1. plan view B. Back the spindle away from the anvil 2. assembly print C. Rotate the spindle counterclockwise 3. subassembly print D. Release the thimble cap 4. detail print E. Tighten the thimble cap F. Bring the spindle into contact with the anvil 1-44. The blueprints thatyou will use most 40 In answering items 1-50 and 1-51, refer oftti in shop work are knownas to figure 1A. 1. plan iews 2. assemLiy prints 1-50. What type of lay is required bythis 3. subassembly prints drawing? 4. detail prints 1. Angular in both directions to surface boundary line 1-45. Which of the following types of view is 2. Parallel to the surface boundary line most commonly used on detail prints? 3. Multidirectional with respect to the 1. Isometric surface boundary line 2. Perspective 4. Perpendicular to the surface boundary 3. Orthographic line 4. Auxiliary 1-51. What is the maximum permissibleroughness 1-46. Which section of a blueprintfor a part height rating? contains the pattern number of the part? 1. X.007 1. Reverse side 2. 52 2. Upper right-hand corner 3. 3 3. Upper left-hand corner 4. 0.005-3 4. Title box

For items 1-47 through 1-49, refer to Learning Objective:Locate and textbook figures 3-2 through 3-5. correctly interpret dimensions on blueprints. Textbook pages 3-7 1-47. Which symbol indicatesa short break? through 3-10.

2. Awnivvvvvv. 3. 1-52. What is the decimal equivalent of 1/32 4. r---- I inch? 1. 0.625 in. 1-48. Which symbol indicates parallelism? 2. 0.0625 in. 1. 3. 0.0313 in. 2. 4. 0.313 in. 3. 4 1-53. One inch is equal to howmany millimeters? 1. 1.00 mm 1-49. Which symbol indicates concealededges? 2. 2.54 mm 3. 25.40 mm 2. 4. 100.00 mm 3. 4. 1-54. How many inches are there in 190.5 millimeters? 1. 7.5 2. 8.0 0,005-3 3. 8.5 52 23 4. 9.0

mar i" 1-55. Tolerance is the difference betweenthe allowable minimum and maximum dimensions.

Figure lA

5 A I- 4° Figure 1B

In answering items 1-56 through 1-58, refer to figure 1B. Learning Objective: Identify the terminology and procedures used 1-56. What is the -otal tolerance of dimension during layout. Textbook pages 3-10 A? through 3-18. 1. 0.0005 in. - 2. 0.001 in. 3. 0.002 in. 1-61. The term layout is used to describe the 4. 0.006 in. 1. positioning of parts on the workbench 2. marking of metal surfaces as an 1-57. What is the maximum permissible length of outline for machining dimension B? 3. guide which aids in the disassembling 1. 2.0 in. of the equipment to be repaired 2. 2.05 in. 4. orfginal drawing used to make a 3. 2.005 in. blueprint 4. 2.0005 in. 1-62. The usual way of improving the visibility 1-58. What is the short limit of dimension D? of layout lines on the surface of a metal 1. 5/8 in. is to 2. 11/16 in. 1. coat the metal surface with layout 3. 3/4 in. dye before inscribing 4. 13/16 in. 2. retrace the lines with chalk 3. rub the surface with chalk before 1-59. A shaft 2.276 inches in diameter is inscribing fitted into a hole 2.275 inches in 4. exert heavy pressure on the scribe diameter. The difference in the diameters of the shaft and the hole is called the 1-63. What devices should you place under 1. clearance allowance layout work to vary its height? 2. interference allowance 1. Surface plates 3. tolerance 2. Parallel blocks 4. isometric allowance 3. Angle plates 4. V-blocks 1-60. How can you assure that the required clearance allowance will be kept while 1-64. What procedure is uced in layouts to some tolerance is permitted between a maintain the best accuracy? shaft and the hole into which it fits? 1. Use each preceding layout line as a 1. Give both the shaft and the hole a reference for the next line plus tolerance 2. Establish a baseline to which all 2. Give both the shaft and the hole a other lines are referenced minus tolerance 3. Establish a minimum of two reference 3. Give the shaft a plus tolerance and lines and refer to both in laying out the hole a minus clearance successive lines 4. Give the shaft a minus tolerance and 4. Always place layout lines in such a the hole a plus tolerance way that a maximum amount of material is removed from one surface 1-65. When inscribing a line or a metal surface, 1-67. Which of the following tools may be used how should you position the handle of the in conjunction with a surface plate? scratch awl you use with reference toa 1. Sine bar straightedge and the direction of move- 2. Angle plate ment? 3. Parallels 1. Point it opposite to the direction 4. Each of the above of movement and over the straightedge 2. Point it in the direction of movement and over the straightedge 3. Point it opposite to the direction of movement and away from the straight- edge 4. Point it in the direction of move- ment and away from the straightedge

1

A b B Figure 1D

41 In answering items: 1-68 and 1-69, refer to figure 1D. a

1-68. In drawing a line perpendicular to line BC through point A, you first prick punch point A. Your second step is to 1. draw arc BC C 2. A0=AC prick punch points B and C 2 3. draw arcs 1 and 2 Ab:AB 4. prick punch point D 2 1-69. Arc 2 is drawn with dividers centered on point Figure 1C 1. A 2. B 1-66. What is the best way to find the center 3. of the rectangle ABCD shown in figure 1(? 4. D 1. Scribe a line parallel to AC through point b; find the midpoint of this line 2. Scribe lines from points a and b square with the edge until they intersect 3. Scribe a line from A to D and another from B to C 4. Scribe two arcs with radius Aa In answering items 1-70 and 1-7l,'Tefer 1-70. Your first step is to 40 to figure 1E. Youaresdrawirig a line 1. prick punch point A perpendicular to line BC thrOugh point A. 2. draw arcs B and C 3. draw arcs at D and E 4. prick punch points D and E

1-71. Your second step is to 1. prick punch point A 2. draw arcs B and C 3. draw arcs at D and E 4. prick punch points D and E

1-72. When scribing parallel lines 2 inches

A apart using dividers to establish the points you need, you set the dividers to 1. 1 1/2 in. 2. 2 in. 3. 6 in. C 4. any convenient length

Figure lE

8 Assignment 2

Layout and Bcnchwork; Metals and Plasti,:,

Textbook Assignment: Pages 3-18 through 4-8

Learning Objective: 7dentify the terminology and procedures used to layout flange bolt holes. Textbook pages 3-18 through 3-21.

2-1. The straight-line distance between the centers of two adjacent flange bolt holes is called the 1. horizontal bisector 2. vertical bisector 3. pitch circle 4. pitch chord

2-2. The horizontal line across the face of the flange is called the 1. vertical bisector 2. horizontal bisector 3. pitch chord 4. pitch circle Figure 3A 2-3. What is the flange bolt hole circle In answering Items 2-6 through 2-10, called? 41 refer to figure 3A. 1. Pitch circle 2. Horizontal bisector 2-6. The horizontal bisector in figure 3Ais 3. Pitch chord indicated by line 4. Vertical bisector 1. AC 2. AD 2-4. What is the name of the vertical line 3. BE across the face of a flange? 4. DF 1. Pitch circle 2. Horizontal bisector 2-7. The pitch chord in figure 3A is indicated 3. Pitch chord by 4. Vertical bisector 1. line AC 2. line AE 2-5. How many pitch chords are used in laying 3. line BC out a 6-hole flange? 4. CF 1. Six 2. Two 2-8. What line in figure 3A bisects a pitch 3. Three chord? 4. Four 1. Line CE 2. Line DE 3. Line FE 4. Line CB

9 2-9. What part of the construction shown in 2-15. In the benchwork required to restore figure 3A is located first when a valve equipment to operational status, what flange is laid out for drilling? are the first and last steps respectivel: 1. Line BC 1. Get information about the equipment 2. Line DF and test it 3. Point A 2. Disassemble the equipment and 4. Point E reassemble it 3. Inspect the equipment for defects 2-10. When the pipe flange in figure 3A is and repair those uncovered laid out for drilling, witness marks are 4. Inspect the equipment for defects placed on the and reassemble it 1. pitch circle 2. pitch chords 2-16. In overhauling equipment, which of the 3. hole centers following precautions should you take 4. hole circumferences to protect the surfaces of parts? 1. Use only the force that is needed in 2-11. The following list is some of the steps disassembling and reassembling you take in laying out valve flange bolt 2. U.e only hammers or with holes. faces made of lead, plastic, or A. raw- Scribe the bolt circle hide B. Draw the bisectors 3. Free stuck bolts or nuts with pene- C. Mark off bolt hole centers trating oil D. Plug the flange opening 4. Take all of the above precautions

In what order do you carry out these steps? 1. A,B,C, D Learning Objective: Identify terms 2. B,C,A, D and procedures associated with 3. D,A,B, C precision work. Textbook pages 3-23 4. D,C,B, A through 3-32. 2-12. The pitch chords of a 6-hole pipe flange are equal to the 2-17. In metal workings scraping is used 1. radius of the pitch circle primarily to 2. diameter of the pitch circle 1. remove sharp edges from castings 3. radius of the flange 2. produce curved surfaces 4. inside diameter of the pipe 3. smooth a machined surface 4. prepare castings for machining 2-13. What is the approximate pitch chord ofa flange that has 5 bolt holes and a pitch 2-18. You are scraping a flat surface to diameter of 4 inches? achieve a correct clearance. Why do you 1. 0.59 in. need to use prussian blue in this work? 2. 1.18 in. 1. It sticks to the high spots on the 3. 2.00 in. workpiece and shows up the areas that 4. 2.35 in. should be scraped 2. It helps prevent "frictional drag" in the scraping operation Learning Objective: Identify basic 3. It helps to maintain longitudinal as terminology and procedures associated well as radial clearance on the flat with Benchwork. Textbook pages 3-21 surface through 3-23. 4. It keeps chips from breaking off the edges when the part is operating agail

2-14. Benchwork includes all EXCEPT which of the 2-19. A solid metal surface which has across- following types of work? hatched appearance has been correctly scraped because cuts were made atan 1. Machining a part of a piece of angle of 90° to each other. equipment 2-20. 2. Makini. layouts of parts One reason for removing burrs and sharp 3. Fittirg mating parts of equipment edges from machined pieces is to precisely prevent damage to the equipment you are 4. Assembling and disassembling equipment repairing.

10 f."-,1 2-21. Machine reaming is more accurate than hand reaming. Learning Objective: Identify the 2-22. You are going to use a reamer which has three types of fits and characteristics a diameter of 1/4 inch. Which of the and manufacture of each type. Textbook following is the properly sized rough pages 3-32 through 3-34. hole? 1. 0.2500 in. 2. 0.2350 in. 2-30. What are three types of fit of plain 3. 0.2505 in. cylindrical parts? 4. 0.2600 in. 1. Interference, clearance, transitional 2. Clearance, moderate, transitional 2-23 Which of the following tools is used to 3. Transitional, moderate, interference shear a particular shape of hole during 4. Clearance, loose, tight the machining process? 1. Reamer 2-31. What is the PRI( Y reference for 2. Broach dimensional Biz and maintenance matters? 3. Scraper 1. The manufaccuers' technical manual 4. Babbitt 2. The appropriate NAVSHIP's Technical Manual 2-24. When you cut threads in a blind hole, 3. The ship's preventive maintenance what tap should you use first? program 1. Taper 4. The appropriate Preventive Maintenance 2. Bottoming System Maintenance Requirement Card 3. Plug 4. Cutting 2-32. What class of fit includes locational fits? 2-25. What size tap drill should you select 1. Clearance fits for a 3/8 -20 NC tap? 2. Transitional fits 1. 0.3906 3. Interference fits 2. 0.3680 4. Transitional and interference fits 3. 0.3250 4. 0.3125 2-33. Which of the following classes of fits moFt likely requires the use of heat? 2-26. A tap that is NOT perpendicular to the 1. Class 1 surface being tapped will usually align 2. Class 2 itself if it is turned into the hole a 3. Class 3 few additional turns. 4. Class 4

2-27. The size of a die is usually found on the 1. trailing face of the die Learning Objective: Identify the 2. edge of the die correct uses of hydraulic presses. 3. leading face of the die Textbook pages 3-34 and 3-35. 4. case of the die

2-28. The easiest and least damaging method 2-34. Tha only way to determine the amount of of removing a broken tap is to break the pressure exerted by a hydraulic press tap into small pieces by using a punch is to watch the pressure gage. and a hammer. 2-35. What should you do to prevent mutilation 2-29. Why should you NEVER add water to acid? of the surface of a workpiece that is 1. The acid solution is premixed being pressed? 2. Acid should be used full strength 1. Increase ram pressure 3. The acid may react violently 2. Lubricate ram pressure 4. Water will cause the tap to rust 3. Heat the workpiece 4. Insert a soft metal plate between the work and the ram 2-36. What should you do to prevent seizing 2-42. From the flame characteristics listed between mated parts that are being below, select the characteristics ofa force-fitted by a hydraulic ram? neutral flame. 1. Increase ram pressure 2. Lubricate the parts A. Sooty 3. Heat the parts B. Bluish-white 4. Insert a soft metal plate between C. Yellowish the work D. Bright inner cone E. Long and bushy F. Outer flame envelope

Learning Objective: Identify 1. A, B, D terms and procedures associated 2. E, F, B with oxyacetylene welding. Text- 3. D, A, E book pages 3-35 through 3-39. 4. B, D, F

2-43. If a flashback occurs, you should 2-37. Compressed oxygen should NEVER come into immediately shut off the torch oxygen contact with oil or grease becausean valve and then shut off the acetylene explosion could occur. valve.

2-38. What color is the oxygen hose? 1. Red 2. Green Learning Objective: Identify types 3. Blue and uses of fastening devices.Text- 4. Yellow book pages 3-39 through 3-48. 2-39. On an oxyacetylene welding machine, how can the thread direction be used to 2-44. Two general groups of fasteners identify the oxygen and acetylene hose commonly used by a Machinery Repairman connections? ara threads and keys. What is the third 1. The oxygen hose connection has left- grcu,? hand threads; the acetylene hose 1. Nuts connection has right-hand threads 2. Pins 2. Both acetylene and oxygen hose 3. Bolts connections have left-hand threads 4. Stays 3. Both acetylene and oxygen hose connections have right-hand threads 2-45. After a nut which has been completely 4. The oxygen hose connections have torqued down, what is the minimum number right-hand threads; the acetylene of full bolt threads allowed to protrude hose connections have left-hand above the nut? threads 1. One 2. Two 2-40. What is the maximum amount the acetylene 3. Three cylinder valve should be opened? 4. Four 1. 1/4 turn 2. 1/2 turn 2-46. What is the designation for a Woodruff 3. 1 turn key with a diameter of 3/8 inch and a 4. 1 1/2 turns width of 1/16 inch? 1. 203 2-41. What is the maximum working pressure of 2. 206 acetylene? 3. 403 1. 5 psig 4. 606 2. 10 psig 3. 15 psig 2-47. Taper pins are usually installed with a 4. 20 psig small hydraulic press.

2-48. Which of the following types of pins is used to align the end casing and housing of a pump? 1. Cotter pin 2. Taper pin 3. Dowel pin 4. Any of the above

12 2-56. Which of the following terms best Learning Objective: Identify the describes the ease with whicha metal basic properties of metals which may be planed and shaped? affect the shaping and uses of 1. Malleability the metals. Textbook pages 4-1 2. Plasticity through 4-3. 3. Ductility 4. Machinability

In items 2-49 through 2-51, select fromcolumn B the behavior of the metal that is made possible by the property in column A. Learning Objective: Identify the characteristics and uses of ferrous A. Property B. Behavior metals. Textbook pages 4-3 through 4-6. 2-49. Ductility 1. Enables a metal to resist breaking 2-50. Tensile 2-57. Which of the following materialsare strength 2. Enables a metal to be melted together to make cast iron? rolled or hammered 1. Steel and iron ore 2-51. Toughness into sheets 2. Iron ore and pig iron 3. Pig iron and scrap iron 3. Enables a metal to be 4. Scrap iron and steel drawn out or pulled into wire form 2-58. The grade of carbon steel alloys produced in converting pig iron to steel 4. Enables a metal to is determined by the resit pulling apart 1. amoun, c' carbon burned out in under stress refihAn, 2. amount 01 noaferoj_ netr.t refining 2-52. If a part having a factor of safety is 3. mixtnic e: coke and limestone used designed to withstand a working load of in refining 1150 pounds per square inch (psi), its 4. amount of carbon adA,t1 afor !fining ultimate strength is at least 1. 1150 psi 2-59. High carbon sttc: is commonly used for 2. 1600 psi which of the fol.:',wing applications? 3. 1950 psi 1. Ship framing 4. 2300 psi 2., Ship plating 3. Cutting tools 2-53. High fatigue resistance is desirable in 4. Electric wiring a material that is subjected to 1. abrasion 2-60. Which of the following metals is 2. repetition of stress contained in atainless steels? 3. corrosive substances 1. Molybdenum 4. high temperatures 2. Chromium 3. Tungsten 4. Vanadium 2-54. A coarse-grained surface over part ofa break in a steol4shaft indicates the area of 2-61. Which of the following metals is used 1. abrasion for valves for high-temperature, high- 2. crystallization pressure, piping systems? 3. final failure 1. Tungsten steel 4. early failure 2. Bronze 3. Copper 2-55. The heat resistance of a metal is 4. Carbon-molybdenum steel indicated by its ability to 1. conduct heat 2. withstand stress at high temperatures 3. maintain a temperature that differs Learning Objective: Identify the from the surrounding temperature characteristics and uses ofnon- 4. maintain constant dimensions under ferrous metals. Textbook pages wide variations in temperature 4-6 through 4-8.

13 2-62. Which metal is commonly used for objects 2-66. Which of the following metals requiring high electrical conductivity? has the 1. Tin greatest weight per unit volume? 1. Bronze 2. Brass 2. Cast iron 3. Copper 3. Lead 4. Zinc 4. Copper-nickel alloy 2-63. Which metal is the strongest and best to 2-67. True brass is produced by .--loying use on-board ship because of its high 1. copper and zinc resistance to the corrosion effect of 2. saltwater? copper and nickel 3. bronze and tin 1. Aluminum 4. 2. Copper copper, aluminum, and phosphorus 3. Bronze 2-68. 4. Copper-nickel Which of these materials is usedin K Monel but not in regular Monel? 1. Iron 2-64. Sherardized steel sheet has a coating of 2. Aluminum zinc applied by 3. Silicon 1. electroplating 4. Cobalt 2. depositing vaporized zinc 3. rolling 2-69. 4. hot dipping K-Monel metal can be madeeasier to machine by 1. 2-65. Which of the following metals soaking in brine at least 24 hours is used to before machining protect a steel-hulled ship against the 2. effects of electrolysis? annealing immediately before machining 3. 1. Iron alloying with copper several days 2. Copper before machining 4. 3. Lead sherardizing with zinc immediately 4. Zinc before machining

14 f, Assignment 3 Metals and Plastics; Power Saws andDrilling Machines

Textbook Assignment; Pages 4-8 through 5-3

3-7. 'What marking designation in the Aluminum Association Marking System identifies Learning Objective: an Identify aluminum which is more than 99% standard metal marking systems pure with no control over impurities? and characteristics of marked 1. 1075 metals. Textbook pages 4-8 through 4-14. 2. 1999 3. 2030 4. 3056

3 -1. Which of the following systems are used Items 3-8 and 3-9 refer to an aluminum for marking iron and steel? alloy bearing the Aluminum Association 1. AA, AMS designation 5052-H16. 2. ANSI, MIL-S-XXXX 3. CDA, ASME 3-8. The number 5052 in the designation 4. SAE, AISI indicates that the major alloy is 1. magnesium 3-2. A 4- or 5-digit SAE number is used to 2. silicon identify 3. manganese 1. nonferrous metals 4. copper 2. plain 6teels 3. alloy steels 3-9. The number H16 in the designation shows 4. plain and alloy steels that the aluminum is 1. strain hardened, then partially 3-3. What AISI number rep-esents an alloy annealed and 1/4 hard steel containing 5% nickel and 1/5% 2. carbon? strain hardened only and 3/4 hard 3. strain hardened, then stabilized and 1. 2205 1/2 hard 2. 3105 4. artificially aged only and 3/4 hard 3. 5220 4. 2520 3-10. What technique is used in markinga steel bar according to the continuous identifi- 3-4. The SAE designator 1050 indicatesa cation marking system? 1. carbon-molybdenum steel 1. A continuous strip of specified 2. nickel steel width is painted along the entire 3. medium carbon steel length of the bar 4. copper-nickel alloy 2. The appropriate marking is printed with heavy ink at specified intervals 3-5. What is the approximate content of along the bar's length alloying elements in a free cutting 3. The appropriate marking is punchedon steel with the claisification SAE 1115? with a metal stamper at specified 1. 1% manganese and 0.15% carbon intervals along the bar's length 2. 1% phosphorus, 1% sulfur, and 5% 4. The appropriate symbol of specified carbon color is painted on each end of the 3. 11% chromium and 5% nickel bar 4. 11% carbon and 157 chromium

3-6. What are the chemical symbols for the elements in plain bronze? 1. Cu and Ni 2. Cu and Sn 3. Fe and V 4. Sn and Zn

15 6/1`)i 3-11. What information is shownon metals marked with the continuous identification Learning Objective: marking system? Identify the steps performed and the results 1. Producer's name or registered trade- obtained when the spark test is used mark and commercial designationof to identify metals. the steel Textbook pages 4-14 through 4-17. 2. Name and trademark of the producer who finished the steel beforeit was marketed 3-18. The reliability of the sparktest in 3. Military Standards designation and identifying metals depends on what Federal Government job order number conditions? 4. U.S. Bureau of Standards quality 1. A properly lighted, draft-free control number and SAE designation testing location 2. A clean, dressed, 30- to 60-grain 3-12. Thin copper wire is identified by grinding wheel 1. continuous identification marking 3. The same wheel speed and feed 2. spot symbols pressure for both the known test 3. peripheral symbols specimen and the unknown sample 4. tagging 4. All of the above 3-13. Which symbol designates the physical 3-19. In the spark test, why is it important condition of a metal? to apply medium pressure against the 1. CI' grinding wheel? 2. CR 1. 3. CQ Hard pressure will increase the 4. CO temperature of the spark stream and the burst, giving an impression of much higher carbon content than that 0 In answering items 3-14 through 3-17, in the metal refer to textbook table 4-2. 2. Hard pressure will cause the spark stream to be diminished or eliminated, 3-14. The characteristic color ofa newly filed surface of aluminum is giving an impression that there is little or no carbon in the metal 1. light gray 3. 2. dark gray Hard pressure will cause the color of the spark stream to change, 3. white 4. dark silver throwing off identification of the metal entirely 4. Too little pressure can cause the 3-15. Which of the following metals, when it spark stream to be too short and the is in the unfinished state, has a smooth volume of sparks to be too few for surface but is velvety in appearance? identification 1. Aluminum 2. Lead 3-20. If the spark stream has shafts and forks 3. Gray cast iron only, the metal under test is 4. White cast iron a 1. steel of high carbon content 2. steel of low carbon content 3-16 Which of the following metals produces 3. nickel alloy short chips when turned on a lathe? 4. molybdenum alloy 1. Aluminum 2. Copper-nickel 3-21. Which of the following metals 3. Nickel-copper gives off tiny blocks of brilliant white light? 4. Bronze 1. Nickel alloy steel 2. High carbon steel 3-17. If a metal coated with green oxide 3. Molybdenum steel reacts positively to the magnet test, 4. Silicon alloy steel it is probably composed of 1. nickel 3-22. The presence of a large quantity of 2. copper white sparks indicates that the metal is 3. bronze 1. aluminum 4. stainless steel 2. cast steel 3. wrought iron 4. high carbon steel

16 ; 3-29. Slow cooling to room temperature is Learning Objective: Identify the required for annealing steps performed and the results 1. copper obtained when the acid test is used 2. brass to identify metals. Textbook pages 3. Stellite 4-18 and 4-19. 4. Monel

3-30. What process is used to 3-23. How should you mix acid and water during help retain the cutting edge on chisels? preparations for making an acid teat? 1. Annealing 1. Pour the acid rapidly into the water 2. Process annealing 2. Pour the acid slowly into the water 3. Normalizing 3. Pour the water rapidly into the acid 4. Hardening 4: Pour the water slowly into the acid 3-31. What happens to a steel that is heated 3-24 The first step that should be taken if to its critical temperature? acid is splashed on the hand of t'he man 1. Nothing if the steel is cooled carrying out a nitric acid test is to gradually 1. wash the skin with soap and water 2. Nothing if the steel is quenched in 2. send the man to sick bay water or oil 3. call a hospital corpsman or the 3. The steel is always made more medical officer machinable 4. rinse the skin with a great deal of 4. The grain structure and physical water properties of the steel are changed noticeably 3-25. No reaction to the acid test indicates that the metal is one of the 3-32. In which of the following heat treatments 1. molybdenum steels is the metal always cooled rapidly by 2. nickel steels quenching? 3. stainless steels 1. Annealing 4. tungsten steels 2. Normalizing 3. Hardening 3-26. What metal gives a quick reaction and 4. Tempering a blue-green color when a drop of nitric acid is applied to it? 3-33. Why is oil sometimes used as a quenching 1. Copper medium for the hardening of steel? 2. Wrought iron 1. To slow down the rate of cooling 3. Aluminum 2. To prevent surface corrosion 4. Nickel 3. To provide carbon impregnation of the surface 3-27. A slow reaction and a pale green color 4. To produce greater hardness after nitric acid is placed on a metal indicates that the metal probably con- 3-34. In which of the following heat treatments tains the element is the temperature held below the 1. iron critical temperature of the metal? 2. copper 1. Normalizing 3. aluminum 2. Hardening 4. nickel 3. Tempering 4. Case hardening

Learning Objective: Identify the 3-35. A metal is case hardened to produce purposes and procedures of heat greater treating metals. Textbook pages 1. corrosion resistance 4-19 through 4-21. 2. surface hardness 3. uniformity of internal stress 4. uniformity of carbon distribution 3-28. Which effect results from the annealing of a metal? 1. Softening Learning Objective: Identify the 2. Hardening characteristics and uses of standard 3. Improvement of corrosion resistance hardness tests for metals. Textbook 4. Reduction of malleability Pages 4-21 through 4 '-27,

17 3-36. Standard hardness tests are based on a 3-42. Which of the following substances metal's resistance to penetration is a basic element of most plastics? because penetration resistance 1. Sodium chloride 1. varies more than other types of 2. Carbon hardness 3. Aluminum 2. is easier to measure accurately than 4. Silicon other types of hardness 3. is the most important quality in 3-43. Which of the following properties is metals for shipboard use a 4. is the only possible definition distinct characteristic of thermoset- of tings? hardness 1. Elasticity 2. Fire resistance 3-37. After you have placed the metal on the 3. anvil of the Rockwell tester Tendency to absorb moisture at the 4. Malleability start of the test, what is the first thing that you should do? 3-44. Which of the following properties is 1. Apply the minor load a distinct characteristic of thermo- 2. Apply the major load plastics? 3. Turn the zero adjuster 1. 4. Hardening on exposure to heat Bring the test piece into contact 2. with the penetrator Softening on exposure to heat 3. Rapid conduction of heat 4. Effective insulation of heat 3-38. When you read the hardness numberon the Rockwell tester dial, what are the posi- 3-45. The thermoplastic most resistant tions of the major and minor loads? to heat distortion is called 1. The minor load rests on the specimen 1. lucite and the major load is raised 2. celluloid 2. The major load rests on the specimen 3. nylon and the minor load is raised 4. polythene 3. Both loads rest on the specimen 4. Both loads are raised 3-46. You can use a fire test to differentiate between thermoplastics and thermosettings 3-39 If the hardness of a hard steel sample because a thermoplastic will burn were measured in a Brinell tester, how readily and a thermosetting will resist burning. large a load would be applied? 1. 500 kg 3-47. 2. 720 kg You are working with a thin laminated plastic that breaks when bent sharply. 3. 1,500 kg 4. 3,000 kg In all likelihood, the layers ofthis plastic are made of 1. wood 3-40. All EXCEPT which of the following hard- 2. glass ness tests are based on the principle of 3. canvas penetration of a soft material by a 4. paper harder one? 1. Rockwell test 3-48. Why is it important NOT to feed 2. Brinell test the work into a saw too fast when you 3. Scleroscope test are sawing plastics? 4. Vickers test 1. Since plastics do not take away heat 3-41. A metal which offers considerable generated by a saw, it is easy to burn work resistance to a file but can be filed by 2. Since plastics are sawed easily and repeated effort is said to be 1. soft quickly, it is easy to make an error 3. The saw might become gummy with 2. hard plastic chips 3. ver hard 4. The saw could be broken by the 4. ex rely hard toughness of the plastic

Learning Objective: Identify the Learning Objective: Identify machine basic characteristics of plastic shop power saw operations and materials. safety Textbook pages 4-25 precautions. through 4-31. Textbook page 5-1.

18 6/ , I. 0 3-49. All EXCEPT which of the following are 3-54. Which blade should be used on a power examples of machine shop work? hacksaw to cut high-speed steel? 1. Cutting metal stock into pieces with 1. Coarse a power saw 2. Regular 2. Drilling holes in flat metal stock 3. Medium with a drill press 4. Fine 3. Grinding cutting edges on cold chisels with a power grinder 3-55. In a power hacksaw, what type of feed 4. Cutting metal pipe into pieces with mechanism automatically controls the an oxyacetylene torch feed when it is cutting through a hard spot in the work? 3-50. Which of the following is a safe 1. Hydraulic practice to be observed by Machinery 2. Mechanical Repairmen while operating a power saw? 3. Gravity 1. Wearing goggles or a face shield 4. Hydraulic or gravity 2. Keeping hands as far from the saw blade as possible 3-56. Which of the following materials is cut 3. Supporting ends of long pieces of on a power hacksaw without the use of a work coolant? 4. Each of the above 1. Mild steel 2. Carbon steel 3-51. Adjusting a power saw while it is in 3. Cast iron operation is an unsafe practice. 4. Brass

3-52. When performing machine work, you should 3-57. What is the recommended cutting speed first stress when a power hacksaw is used to cut 1. accuracy annealed tool steel? 2. efficiency 1. 50 strokes per minute 3. safety 2. 60 strokes per minute 4. speed 3. 90 strokes per minute 4. 136 strokes per minute

Learning Objective: Identify the 3-58. Which of these practices is likely to characteristics and operating pro- cause blade breakage on a power hacksaw? cedures of power hacksaws. Textbook 1. Applying coolant directly to the pages 5-1 through 5-3. blade rather than to the work 2. Failing to align the cutting mark on the work with the blade 3-53. What is the minimum number of teeth that 3. Starting the4machine with the blade must be kept in contact with the work touching the work when .11 power hacksaw is used to cut thin 4. Using a coarse blade to cut cast steel sheet? iron 1. Eight 2. Two 3. Ten 4. Four Assignment 4

Power Saws and Drilling Machines; OffhandGrinding Tools

Textbook pages 5-4 through 6-11

Learning ObjecLive: Identify the characteristics and operating procedures of continuous feed cutoff saws (bandsaws). Textbook pages 5-4 through 5-18.

4-1. What will the continuous feed cutoffsaw do automatically as it completeseach cut? 1. Raise the saw head 2. Stop the drive motor 3. Stop the drive motor and start the coolant motor 4. Stop the drive motor, start the coolant motor, and raise thesaw head

4-2. After the saw nand is installed and stretched properly, band tension is preserved during operation by the 1. tension handwheel 2. hydraulic system 3. V-belt 4. saw guides

4-3. Which of the following operationscan be Figure 4A more easily performed on a tiltable blade bandsaw than on a tiltable table handsaw? In answering Items 4-4 through 4-7,refer 1. Cutting long pieces to figure 4A. 2. Contour cutting 3. Mitering 4-4. The saw segment has a pitch of 4. Polishing 1. 7 2. 8 3. 9 4. 10

4-5. The saw segment has a width of 1. 0.024in. 2. 0.040in. 3. 0.25 in. 4. 1 in.

4-6. What is the gage of thesaw segment? 1. 0.008 in. 2. 0.016 in. 3. 0.024 in. 4. 0.040 in.

20 t. 4-7. What is the set of the teeth of the saw 4-15. Excessive wear between a fabric polishing segment? band and its guide is prevented by 1. 0.008 in. 1. cutting oil applied to the work 2. 0.020 in. 2. water coolant applied to the work 3. 0.032 in. 3. a graphite impregnated fabric-face on 4. 0.040 in. the backup strip 4. lubricating oil fed from the pressure 4-8. A sawband having which set pattern is system used to cut metal pipes? 1. Raker 4-16. What factor limits the gage of the saw 2. Straight band that can be used with a particular 3. Wave band tool machine? 4. Any of the above 1. Type,of feed 2. Size of the band wheels 4-9. Which type of saw band is likely to be 3. Type of band guide used for cutting solid slab stock? 4. Range of band speeds available 1. Straight set, temper B 2. Wave set, temper R 4-17. What factors influence the quality of 3. Raker set, temper A work produced with a metal cutting 4. Straight set, temper A bandsaw? 1. Band speed 4-10. The ends of a file band are joined with 2. Feed pressure the 3. Band type 1. gate clip and tail gate 4. All of the above 2. spacer and gate clip 3. segment and spacer 4-18. Which bandsaw setup is correct for 4. tail gate and segment cutting cast steel with a maximum thickness of 2 inches? 4 -1].. A file-band spacer is inserted between the 1. Pitch8,velocity50fpm 1. gate clip and tail gate 2. Pitch10,velocity50fpm 2. gate clip and back band 3. Pitch12,velocity75fpm 3. back band and file segment 4. Pitch14,velocity125 fpm 4. file segment and tail gate 4-19. Which setup is correct for cutting 4-12. The abrasive material on a polishing band 3/4 inch cast iron on the metal-cutting is carried on a backing of bandsaw? 1. treated paper 1. Medium feed pressure, velocity 200 fpm 2. fabric 2. Heavy feed pressure, velocity 200 fpm 3. steel 3. Light feed pressure, velocity 225 fpm 4. rubber 4. Medium feed pressure, velocity 150 fpm

4-13. The upper movable band guide of a bandsaw 4-20. Which saw band should be used for a 3- should clear the workpiece by inch radius cut in a 1-inch aluminum 1. 1/4 in. sheet? 2. 1/2 in. 1. 1/2in.wide, 8-pitch band 3. 1 1/2 in. 2. 1/2in.wide,16-pitch band 4. 2 in. 3. 5/8in.wr.ic,16-pitch band 4. 3/4in.wide, 6-pitch band 4-14. When using a file belt on a metal-cutting bandsaw, you replace the standard bandsaw 4-21. Manual work feed on a bandsaw is generally guides with used only on materials up to 1. insert type guides 1. 1/4 in. thick 2. roller type guides 2. 1/2 in. thick 3. lubricant-impregnated, fabric-faced 3. 1 in. thick guides 4. 1 1/2 in. thick 4. metal backup support strips 4-22. Inadequate feed pressure on work in a bandsaw is likely to 1. break the teeth of the saw band 2. dull the saw band 3. snag the saw band 4. bind the saw band in the work

21 4-23. Which cut on a bandsaw requires the use 4-28. of a butt welder? Before starting to cut metalwith a 1. Inside cut bandsaw, what shouldyou always be sure to adjust? 2. Straight cut 1. 3. Angular cut The band guide insertsso they clear 4. Disk cut the angle of cut 2. The worktable so its levelmatches 4-24. The correct length for the angle of cut a replacement band 3. on a two-wheel bandsaw is equal to The upper band guideso it clears 1. twice the circu.nference of the work by 3/8 to 1/2 inch one wheel 4. pus the distance between wheel All of the above centers 4-29. 2. twice the distance between wheel Which factors determinethe tension to be centers plus ;1,- circumference of applied to a newly installedsaw band? one wheel 1. Set and gage of the band 2. 3. twice the sum of the distance Width and gage of the band between 3. wheel centers plus the circumference Width and temper of the band of two wheels 4. Temper and gage of the band 4. three times the distance between 4-30. wheel centers plus the circumference Inadequate tension ona saw band is of one wheel likely to cause 1. wandering 2. overheating 3. dulling 4. snagging

4-31. Corner'holes are usedon a complex saw workpiece to permit theuse of 1. higher cutting speeds 2. a narrower band B 3. a thinner gage 4. a smaller pitch

4-32. What type of feed is usually usedfor filling operations on a band tool machine? 1. Gravity 2. Hydraulic C D 3. Mechanical 4. Manual Figure 4B

4-25. Which of the saw band ends in figure 4B Learning Objective: is properly prepared for splicing? Identify 1 A characteristics of drills and 2. B drilling machines and procedures 3. C which an MR must followduring 4. D their use. Textbook pages 5-18 through 5-33. 4-26. Which step follows the weldingand grinding of a spliced saw band? 4-33. 1. Annealing To drill a hole usingan upright drill 2. Polishing press, you position the workpiece;using 3. Quenching a radial drill press you position the 4. Installing drilling head.

4-27. Improper tracking of a newly installed saw band is corrected by adjustment of the 1. band tension 2. band guides 3. backup bearings 4. wheel tilt control

22 4-34. For which of the following types of work 4-38. What is the function of part A? is the sensitive drill press particularly 1. To cut the material as the drill is useful? fed to the work 1. Work requiring many holes to be 2. To provide side clearance for the drilled in a large piece of metal drill body 2. Large castings requiring holddown 3. To center the drill on the work clamps during drilling 4. To provide chip clearance as the 3. Work requiring the operator to drill advances through the work rely on his sense of touch to determine how the drill is cutting 4-39. Which part is intended to simplify the 4. Work requiring high-speed drilling removal of the drill from its mounting? in which vibrations are not harmful 1. D 2. E 3. F 4. H

4-40. Which high-speed drill speed is preferred if alloy steel and cast iron are to be cut without changing drills or spindle speeds? 1. 50 fpm 2. 70 fpm 3. 100 fpm 4. 150 fpm

4-41. What is the approximate speed of the drill press with which you are drilling a 1/2-inch hole using a twist drill whose cutting speed is BB fpm? 1. 90 rpm 2. 200 rpm 3. 670 rpm 4. 750 rpm

4-42. The feed of a drill press is expressed in 1. centimeters per revolution Figure 4C 2. inches per minute 3. thousandths of an inch per minute 4. thousandths of an inch per revolution In answering items 4-35 through 4-39, 41 refer to the twist drill shown in 4-43. In drilling a hole through a metal plate, figure 4C. you should ease up on the feed pressure as the drill pierces the bottom of the 4-35. The body is indicated by plate. 1. B 2. F 4-44. To line up the center-punch mark on the 3. G workpiece exactly under the spindle when 4. H you are getting ready to drill, you will find it useful to 4-36. The land consists of parts 1. use a drill larger than the required 1. A and B size to make the lead hole 2. C and D 2. insert a dead center in the spindle 3. E and F socket 4. G and H 3. chisel a groove away from the punch- mark 4-37. The difference in the diameters of points 4. use a counterbore pilot to guide your CB-AD is to drill to the punchmark 1. facilitate removal of the drill from the spindle of a drill press 2. provide the body clearance that helps to reduce drilling friction 3. separate the flutes of the drill 4. accentuate the taper at the tip of the drill

23 6 4-45. You are to drill a large hole in a 4-48. What type of shank is found curved piece of brass.Your twist drill on a reamer has a dead center as large designed for use in a drillpress or as the center- lathe? punch mark which you made at the point 1. Straight to be drilled. What should you do to 2. Tapered keep the twist drillon the punchmark 3. Fluted when you start drilling the large hole? 4. Splined 1. Exert heavy pressure on the twist drill at the beginning and then ease 4-49. What is the rate of taper of up after you have drilled awhile a taper pin reamer? 2. Insert a center drill in the spindle 1. 1/8 in. per foot and make a center hole before you 2. 1/4 in. per foot start drilling the large hole 3. 1/3 in. per foot 3. Chisel two small grooves on opposite 4. 1 in. per foot sides of the punchmark 4. Use angle plates to supportyour work 4-50. Which of these items is NOTused to make 4-46. Which of the following practices an angular hole by the Watts method? is 1. Floating chuck recommended for bringing a drill back 2. Broach to center after it has started off 3. center? Guide plate 4. Drill press 1. Remove the drill from the hole and start again 2. Put pressure on the work from the side toward which the center is to be drawn Learning Objective: Identify the proper procedures associated with 3. Chisel a groove on the side of the the setting up and use of bench hole toward which the center isto be drawn and floor mounted grinders. Text- book pages 6-1 and 6-2. 4. Recenter the work on the table under the drill 4-51. To become proficient at grindingsmall handtools and single-edged cuttingtools, you must combine experience and practice with a knowledge of which of thefollow- ing things? 1. The safety precautions to observe 2. The composition of the toolmaterials 3. How to install grinding wheels 4. All of the above

4-52. Before an operator startsto use a grinder, he should read the safety A precautions which are postedon or near the grinder.

4-53. How should the tool reston a bench or pedestal grinder be setup in relation to the grinding wheel? 1. 1/8 inch from the wheelface and level with the center of the wheel C D 2. 1/8 inch from the wheel faceand level with the bottom of the wheel 3. 1/2 inch from the wheel Figure 4D face and level with the center of the wheel 4. 1/2 inch from tht wheel face 4-47. The shaded portion of which and level part of figure with the bottom of the wheel 4D is removed by a countersinkand drill? 1. A 2. B 3. C 4. D

24 p . ; 1 4-54. Why does the operator of a grinder stand In answering items 4-59 through 4-61, select to one side of the machine while starting from column B the grinding wheel bond having it? characteristics listed in column A. 1. To prevent getting injured if the wheel explodes A. Characteristic B. Grinding Wheel Bond 2. To be in position for side grinding 3. To check whether the toolrest is 4-59. When used as cut- 1. Rubber positioned properly off wheel has 4. To inspect the condition of the cool cutting 2. Shellac grinding wheel action 3. Vitrified 4-55. Normally a grinding wheel installed on a 4-60. Strong and shock bench grinder does NOT exceed what resistant 4. Resinoid thickness? 1. 1/4in. 4-61. Not affected by 2. 7/8in. oil, acid, or 3. 1 in. water 4. 11/2in.

4-62. Assume a diamond grinding wheel is marked D 100 C 50 B 1/8". This desig- Learning Objective: Identify the nation indicates the wheel basic characteristics and markings 1. is 1/8 inch wide of grinding wheels. Textbook pages 2. contains manufactured abrasive 6-2 through 6-11. 3. bond is not modified 4. has a grit size of 50

4-56. During grinding operations, the abrasive 4-63. Which of the following changes will make grains on a grinding wheel wear down a grinding wheel "act softer"? causing the wheel to become dull. 1. Reduce the wheel diameter 2. Increase the wheel speed 4-57. The number A 100 D 15 V indicates a 3. Reduce the grain depth of cut grinding wheel with a 4. Increase the arc of contact of the 1. coarse grit and dense structure wheel 2. fine grit and open structure 3. hard bond and aluminum oxide abrasive 4-64. In choosing a wheel for grinding high- 4. soft bond and silicon carbide speed steel, you should select one with abrasive an aluminum oxide abrasive.

4-58. A hard grade grinding wheel possesses 4-65. Which type of bond should a wheel have which of the following qualities? for general purpose grinding? 1. A large number of strong abrasive 1. Resinoid grains 2. Shellac 2. A small amount of bond surrounding 3. Rubber the abrasive grains 4. Vitrified 3. Thick bond posts interlocking the abrasive grains 4-66. What is the recommended grinding wheel 4. Thin bond posts offering greater for surface grinding a high-speed steel resistance to grinding pressure surface? 1. A60K8V 2. C36K5V 3. A46H8V 4. A46K8V

4-67 What can you tell about the condition of a grinding wheel which gives off a dull thud when tapped with a piece of hard wood? 1. It is out of round 2. It is safe to use 3. It has invisible cracks 4. It has been soaked in coolant and baked dry

25 4-68. A purpose of using flangesand cardboard 4-69. Which grinding wheel or rubber washers in installinga condition is caused by leaving part of the grinding wheel ona spindle is to grinding wheel 1. soaking in coolant? remove play of the wheelon the spindle 1. Imbalance 2. 2. Out-of-roundness distribute and even out thepressure on the wheel 3. Grooved grinding surface 4. Cracks 3. hold the wheel on the -spindle 4. grip the wheel so that itcan rotate with the spindle Assignment 5 Offhand Grinding of Tools; Lathes and Attachments

Textbook Assignment: Pages 6-11 through 7-27

5-4. Which angle of the facing cutter is the back rake angle? Learning Objective: Identify the 1. D terms and steps associated with the 2. E orinding of single point cutting 3. F tools. Textbook pages 6-11 through 4. G 6-20.

In items 5-5 and 5-6, select from column B the cutting tool material that is generally used for the Turpose given in column A.

A. Purposes B. Materials

5-5. General Cutting 1. Stellite CUTTING LOGE 5-6. Fine finishing at 2. Carbon tool I low cutting speed steel A -r 3. High-speed steel 4. Tungsten carbide Ii

5-7. In grinding a cutter bit, why should you remove as little of the bit as necessary to obtain the appropriate rake ngles? 1. To enable the bit to cut wi h less chatter 2. To eliminate the use of a co lant during the grinding process 3. To enable the bit to absorb ore of the heat that results during use Figure 5A-Cutting tool terminology. 4. To eliminate the need for ho ing the bit In answering items 5-1 through 5-4, refer to figure 5A. 5-8. In grinding a tool bit, your last step should be to 5-1. Which of the angles of the facing cutter 1. honeiton an oilstone is the side rake angle? 2. grinditto obtain rake angles 1. A 3. grinditto obtain a radius on the 2. B end 3. C 4. grindit to obtain clearance angles 4. D

5-2. The back rake angle is a positive back Learning Objective: Identify the rake angle. characteristics and uses of engine lathe bits. Textbook pages 6-17 5-3. Which angle of the facing cutter is the through 6-21. end relief angle? 1. A 2. B 3. F 4. G

6 4 5-9. What is the direction of feedof a 5-16. Side and front relief angleson steel roundnosed turning tool whichis ground flat on top? turret lathe tools should all beground to 1. Right to left 1. 12° 2. Left to right 2. 10° 3. Either 1 or 2 above 3. 8° 4. Away from the lathe center 4. 5° 5-10. A left-hand or right-hand facing tool 5-17. has a sharp point for the The cutters used on turretlathes are purpose of usually 1. cutting outside threads than the 2. cutting inside threads (larger, smaller) cutters used on engine lathes because 3. machining square corners a turret lathe is designed to 4. machining necks remove quantities of metal (large, small) 5-11. Which of these lathe tools is used to rapidly. machine a groove? 1. 1. Cutoff tool Smaller, small 2. Larger, small 2. Threading tool 3. 3. Turning tool Smaller, large 4. 4. Facing tool Larger, large

5-12. 5-18. The clearance ground on Which of these lathe toolsis usually zue shank of a ground in the shape ofa left-hand carbide-tipped cutter should beslightly turning tool? larger than the clearance angleto be 1. Threading tool ground on the tip in order that 1. 2. Round-nosed turning tool hot.: shank and tip may beground 3. Cutoff tool simultaneously 2. '4. Boring tool the grinding wheelcan be kept off the shank when the tip clearance angle is being ground 5-17, How should you vary the feedand depth 3. better support can be given of cut of the tool bit ingoing 'rom to the roughing to finishing work? tip by the shank 4. 1. Increase feed and depth of the shank can remain intactif the cut tip breaks 2. Decrease feed and depth ofcut 3. Increase feed of cut and decrease depth of cut 4. Learning Objective: Identify the Decrease feed of cut andincrease depth of cut characteristics and rises of shaper and planer tools. Textbook pages 5-14. 6-23 through 6-25. In an engine lathe tool properlyground from a roughing tool toa finishing tool, the side clearance angle will be 5-19. 1. 0° The relief angles of shaper andplaner 2. 4° cutting tools are equal to therelief 3. 5° to 9° angles of lathe cutting tools. 4. 6° to 10° 5-20. What is the mainpurpose of the side rake angle in a cutting tool? 1. To prevent the tool from Learning Objective: Identify the roughing characteristics of cutting tools the surface of the workpiece 2. To prevent binding of the used in turret lathes. Textbook tool on pages 6-21 through 6-23. the workpiece surface 3. To reduCe the power neededto make a cut 4. To reduce the probability 5-15. The back rake angle fora turret lathe of the cutting edge breaking tool used for cutting castiron should be ground to 5-21. 1. 5° Which shaper or planercutting tool is 2. 8° NOT given a back rake angle? 3. be 1. Downcutting tool 4. 12° 2. Shovel nose tool 3. Shear tool 4. Gooseneck tool

28 eJ 5-22. Downcutting in either right- or left- 5-30. The distance between centers on an hand direction may be accomplished by a engine lathe may be adjusted by moving 1. roughing tool the 2. shovel nose tool 1. headstock 3. shear tool 2. tailstock 4. cutting-off tool 3. tailstock and headstock 4. carriage 5-23. Which cutting tool is normally used as a finishing tool? 5-31. Rotation of the tail. , handwheel on 1. Shear tool an engine lathe resul in a movement of 2. Downcutting tool the tailstock 3. Cutting-off tool 1. base 4. Shovel nose tool 2. spindle 3. top 4. clamp bolt Learning Objective: Identify and select some of the purposes of the 5-32. Which part of an engine lathe is attached priilcipal parts of the engine directly to the crossfeed slide of the lathe. Textbook pages 7-1 through carriage? 7-15. ,. Cutting tool 2. Workpiece 3. Tool post 5,-24. In a routine machining operation with 4. Compound rest an engine lathe the workpiece is rotated about a horizontal axis. 5-33. When an engine lathe is used for milling, the workpiece is mounted on the 5-25.)6fheswing of a 16-inch by 8-footlathe 1. headstock and tailstock centers is 8 feet. 2. tailstock spindle 3. carriage 5-26. .What are the upper surface shapes of the 4. face plate ways of a typical lathe? 1, Square or curved 5-34. Which of the following operations on an 2. Curved or V-shaped engine lathe is usually performed with 3. V-shaped or flat the carriage locked in position? 4. Flat or square 1. Turning 2. .Facing 5-27. Driving power is applied to the work- 3. Boring piece on a lathe tfirough the 4. Drilling 1. tailstock spindle 2. headstock sp dle 5-35. The w'ar trains in the apron of an 3. crossfeed sc ew engine lathe are driven by the 4. dead center 1. control rod 2. lead screw 5-28. How many spindle speeds can be obtained 3. reverse rod on a lathe that has a 6-position head- 4. feed rod stock cone pulley? 1, 6 5-36. Friction clutches are operated on the 2. 12 apron to engage and disengage the 3. 18 1. headstock speed 4. 24 2. tailstock 3. power-feed mechanism 5-29. Why does a headstock spindle have a hole 4. hand-feeds running through its center? 1. To permit the bars or rods to pass 5-37. The half-nuts in the apron are engaged through the spindle with the lead screw when an engine lathe 2. To improve the cooling of the is used for gearbox 1. turning 3. To permit thorough lubrication of 2. facing the spindle bearings 3. boxing 4. To dissipate heat from the cutting 4. threading tool

29 5-38. Which of the followingparts of an 5-44. The stud gear of the leadscrew gear engine lathe receive powerthrough the feed rod? train of an engine lathemeshes with the 1. screw gear 1. Headstock spindle and longitudinal 2. idler gear feed mechanism 3. 2. spindle gear Longitudinal feed mechanism and 4. crossfeed mechanism small compound gear 3. Crossfeed mechanism andtailstock 5-45. A rod was threaded with spindle a pitch of 7 on an engine lathe equipped with 4. Tailstock spindle .nd headstock a lead spindle screw having a pitch of 5. Which of the following pairs of changegears were 5-39. In lathes that have used to thread this rod? no feed rod, the 1. feedrod function is performed 15-tooth gear and a 10-toothgear by the 2. 1. rack and pinion 21-tooth gear and a 18-toothgear 3. 2. splined lead screw 35-tooth gear and a 24-toothgear 4. 3. worm gear 42-tooth gear and a 30-toothgear 4. V-ways 5-46. Which ratio is commonly usedfor the 5-40. When an engine lathe is used compound gears of a lathe? for thread 1. 1:1 cutting, the number of threads per inch 2. 2:1 is determined by the relationship 3. 8:3 between the speeds of the 4. 10:1 1. drive motor and spindle 2. spindle and feed rod 5-47. A lathe you are assigned 3. lead screw and feed rod to work on is 4. lead screw and spindle equipped with a quick-changegear box and a sliding compoundgear. One lever 5-41. on the gearbox has three possible The pitch of threads cut byan engine lathe is changed by changing positions while the otherlever has six the positions. 1. spindle drive speed How many screw speedsare available? 2. pitch of the leadscrew 1. 3 3. lead screw gears 2. 6 4. size of the rack pinion 3. 18 4. 5-42. 36 A workpiece in an enginelathe must be threaded with 15 threads per inch. If 5-48. Feeds on the quick-change the lead screw has 10 threads gear box are per inch, identified in terms of which of the followingsets of gears ten thousandths can be used? of an inch per 1. second 1. 15-tooth spindle gear and 10-tooth 2. minute screw gear 3. spindle revolution 2. 15-tooth spindle gear and 30-tooth 4. screw gear feed rod revolution 3. 15-tooth spindle gear and30-tooth screw gear Learning Objective; 4. 20-tooth spindle gear and Identify some 30-tooth of the characteristics screw gear and uses of major lathe attachmentsand accessories. 5-43. Textbook pages 7-15 through Idler gears in a gear trainare used to 7-27. 1. adjust the speed ratiobetween the driving and drivengg,rs 5-49. The toolpost is used only 2. couple the driven gear to provide to the driving rigid support for the gear without affecting the speed toolholder. ratio 5-50, 3. Which type of work is doneon a lathe with stabilize the speed of thedriven the help of a knurling toolattachment? gear with changes in load 1. 4. Trimming an oversize metalworkpiece permit reversal of thedriving gear 2. rotation Roughing the surface ofa round metal workpiece 3. Threading the outside ofa solid metal workpiece 4. Threading the inside ofa solid metal workpiece

30 5-51. What type of lathe chuck is used to hold 5-58. A function of the center rest used on an workpieces that have irregular cross engine lathe is to support sections? 1. long workpieces 1. Scroll chuck 2. workpieces being machined to a 2. 4-jaw chuck noncircular cross section 3. Standard collet chuck 3. especially heavy workpieces 4. Hexagonal collet chuck 4. workpieces that have no indented centers 5-52. What type of lathe chuck can be used to automatically center round workpieces 5-59. A follower rest is used on a lathe to of many sizes? prevent 1. Scroll chuck 1. springing of the work 2. 4-jaw chuck 2. improper centering of the work 3. Standard collet chuck 3. irregular feed pressure in thread 4. Hexagonal collet chuck cutting 4. out-of-round turning of the work 5-53. What type of lathe chuck is preferred for precision turning of small work? 5-60. The guide bar support of a taper attach- 1. Combination chuck ment is connected directly to the 2. Universal chuck 1. carriage saddle 3. Independent chuck 2. headstock 4. Draw-in collet chuck 3. tailstock 4. lathe bed 5-54. What is the angle of the points of Morse-tapered lathe centers? 5-61. A carriage stop may be used on an engine 1. 30° lathe to remove the need for 2. 45° 1. manual operation at the end of a cut 3. 60° 2. individual measurements on duplicate 4. 75° parts 3. setup measurements made directly on 5-55. A tailstock center differs from a the workpiece headstock center mainly in 4. Variable rates of feed across a 1. shank taper workpioce 2. point taper 3. metal hardness 5-62. The depth of a cut made by a milling 4. diameter attachment on an engine lathe is con- trolled by the 5-56. Which mark is used to identify the 1. lead screw tailstock center of an eng!no lathe? 2. cross feed 1. Longitudinal cut 3. tailstock position 2. Dimple 4. longitudinal feed 3. Circular groove 4. Punched depression 5-63. Which type of lathe is constructed in such a way that a piece can bu removed 5-57 Which workholding devices are used in from its bed to accommodate work of combination? large diameter? 1. Tailstock center and clamp dog 1. General purpose screw cutting 2. Lathe dog and driving plate precision lathe 3. Faceplate and collet chuck 2. Toolroom lathe 4. Collet chuck and tailstock center 3. Gap lathe 4. Bench lathe Assignment 6

Basic Engine Lathe Operations)Advanced Engine Lathe Operations

Textbook Assignment: Pages 8-1 through 9-25

6-6. What should be the large diameterof the center hole in a lathe workpiece that Learning Objective: Identify the has an outside diameter of 2 1/2 inches? proper procedures required to set 1. 5/32 in. up an engine lathe for basic lathe 2. 3/16 in. operations. Textbook pages 8-1 3. 5/16 in. through 8-14. 4. 7/16 in.

6-7. In a properly formed center hole, 6-1. What should you use to the remove burrs in lathe centers rest against the the tailstock spindle of a lathe? 1. bottom of the drilled hole 1. A grinder 2. sides of the countersunk hole 2. A tail center coated with lapping 3. inner rim of the countersunk hole compound 4. outer rim of the countersunk hole 3. A 60° taper reamer 4. A Morse taper reamer 6-8. Driving torque is usually appliedto a mandrel through 6-2. To positively align lathe centers without 1. the live center making a test cut, you should use a 2. a lathe dog 1. test bar and indicator 3. a collet chuck 2. center gage 4. a drill chuck 3. Morse taper gage 4. steel rule between the centers 6-9. Which of the following workpieceswould probably be turned on a soft mandrel? 6-3. The tool used to truea lathe center is 1. A plastic gear blank for a 1 1/4-inch fed to the work by means of the shaft 1. longitudinal feed 2. A brass pulley for a 1/2-inch shaft 2. compound-rest feed 3. A steel collar with a nonstandard 3. cross feed inside diameter 4. rotation of the tool post swivel 4. a steel spindle with a nonstandard outside diameter 6-4. Which of the following lathe operations is performed with the workpiece mounted 6-10. Why must the surface of on the carriage? a standard mandrel be lubricated before the work 1. Turning is mounted? 2. Facing 1. To prevent damage to the work when 3. Threading the mandrel is removed 4. Milling 2. To permit free rotation of themandrel on the tail center 6-5. Centers are usually made in finished round 3. To permit free rotation of the workpieces with a work on the mandrel 1. lathe 4. 2. punch To prevent tilting of the workon the tapered surface 3. hand drill 4. drill press

32 6-11. A hollow workpiece that has two cylindri- 6-17. Which of the following attachments must cal surfaces, each with a different axis, you use to accurately machine thread may be turned on an engine lathe by the length of a long shaft? mounting the work on 1. Follower rest 1. a universal chuck 2. Center rest 2. a gang mandrel 3. Either 1 or 2 above 3. an eccentric mandrel 4. Collet chuck 4. an arbor

6-12. The centering of work in a 4-jaw indepen- dent chuck should be checked by Learning Objective: Identify the 1. taking a light test cut steps involved and measurements 2. holding a piece of chalk against the taken in basic engine lathe rotating work machining. Textbook pages 8-15 3. bringing the tail center against the through 8-26. face of the work 4. locating the axis of the cylindrical portion with a combination square 6-18. Cutting speeds on a lathe are stated in units of 6-13. Which of the following precautions should 1. revolutions per minute you take when you chuck a thin-walled 2. feet per minute cylinder in a lathe? 3. inches per revolution 1. Insert paper or shim stock under the 4. thousandths per revolution chuck jaws 2. Expand the chuck jaws against the 6-19. Which metal is machined at the highest bore of the work cutting speed? 3. Use only enough jaw pressure to 1. Bronze prevent slipping 2. Cast iron 4. Adjust the jaws individually to 3. Aluminum prevent distortion 4. Tool steel

6-14. When work is held in a draw-in collet 6-20. The time required to perform a rough chuck for precise machining, what is the turning operation can often be shortened maximum diameter of the collet? by reducing the 1. 0.00001 in. 1. cutting speed and increasing the feed 2. 0.0001 in. 2. depth of cut 3. 0.001 in. 3. longitudinal feed and increasing 4. 0.002 in. cutting speed 4. lubricant flow 6-15. When a universal chuck is used on the headstock spindle of a lathe, the live 6-21. Which of the following lathe operations center should be replaced with a requires the highest cutting speeds? 1. pipe center 1. Rough facing 2. collet chuck 2. Rough turning 3. rag 3. Finish turning 4. block of wood 4. Thread cutting

6-16. Suppose that after you prick punch the 6-22. Which lubricant is preferred for threading center of a workpiece that you mount it a cast iron workpiece? on the faceplate of a lathe. You then 1. Kerosene use the dead center to determine whether 2. Lard oil or not the workpiece is on center. If it 3. Soapy water is on center, which of the Mowing 4. Graphite solution illustrations represents what you would see on the end of the workpiece? 6-23. What is the most common source of chatter 1. 0 in lathe operation? 1. High cutting speed 2. Inadequate lubrication 3. Slow feed 4. Exc.utiive depth of cut 6-24. What is normally the directionof feed 6-31. of a facing cutter? What should you do to keepthe reamer 1. Toward the headstock from overheating? 1. 2. Toward the tailstock Pause for a moment whenyou sense 3. Toward the lathe center the reamer is gettingtoo hot, 4. Away from the lathe center increase the feed, and lubricatethe reamer 2. Chill the reamer before 6-25. When a facing cut is made ina workpiece starting the operation and use a cutting speed on an engine lathe, which feedmoves the of tool? less than 40 fpm 3. 1. Cross feed Chill the reamer beforeyou begin, 2. Longitudinal feed use a cutting speed of 60 fpm, and 3. Compound-rest feed pause if you sense that it is getting 4. too hot Both longitudinal feed and compound- 4. rest feed Lubricate the reamer anduse a cut- ting speed of 40 fpm 6-26. A depth of cut of 0.040 inch reduces the 6-32. Which process is used diameter of a lathe workpiece by to bring a hole 1. 0.020 in. to finished size when highaccuracy is required? 2. 0.040 in. 1. Boring 3. 0.080 in. 2. Coring 4. 0.120 in. 3. Drilling 6-27. 4. Reaming Shoulders are commonly locatedwith a parting tool to eliminate the need for 6-33. Which feed is used when 1. using a pointed turning tool a boring bar is mounted between centers 2. facing the shoulder on a lathe? 1. Cross feed 3. cutting a fillet 2. Longitudinal feed 4. measuring during the rough turning 3. Compound-rest feed 4. Longitudinal feed and cross feed 0 For items 6-28 through 631,assume ti,at you are operating a lathe to drill a 6-34. What is the relationship betwen 1-inch diameter hole througha thick metal the spindle speeds for roughing and block. To complete the job, you plan to use a knurling a particular metal? pilot drill, a finish drill,a boring tool, and 1. Roughing speed is twice knurling a reamer. When drilling, you willuse a cutting speed of 80 fpm. speed 2. Roughing speed is equalto knurling speed 6-28. Failure to feed enough pressure to a 3. Roughing speed is half knurling drill is likely to cause the speed 1. drill to get too hot 2. drill to chatter 6-35. When you refinish a damaged lathe 3. workpiece to be spoiled center, at what angle should you set the compound 4. drill to be broken rest in relation to the lathe spindle axis? 6-29. The flutes of your finish drill are 1. 15° cleared occasionally by 2. 30° 1. running the pilot drill through the 3. 60° hole 4. 90° 2. flushing with lubricating oil 3. backing the drill out 4. reducing the cutting speed of the drill Learning Objective: Identify the terminology and procedures associated 6-30. What is the approximate diameter of the with the turning and boring of hole after you finish the drilling and tapers. Textbook pages 9-1 through boring? 9-7. 1. 3/4 in. 2. 7/8 in. 3. 15/16 in. 4. 63/64 in.

34 6-36. A 4-inch tapered workpiecehas a diameter 6-44. Which of the following devices should you of 3 inches on one end and3 3/8 inches use to check the accuracy of a bored on the opposite end. Whatis the taper taper? of this workpiece? 1. A bevel protractor 1. 0.025 in. per in. 2. An inside micrometer 2. 1/8 in. per ft 3. A dial-indicator cylinder gage 3. 3/8 in. per ft 4. A plug gage 4. 1 1/8 in. per ft 6-45. The boring of a blind tapered hole is 6-37. What is the taper of a shaft that has an usually preceded by included angle of 3° between opposite 1. taper reaming surfaces? 2. drilling to the small diameter of the 1. 1/8 in. per ft taper 2. 3/8 in. per ft 3. drilling to slightly less than the 3. 5/8 in. per ft small diameter of the taper 4. 1 3/8 in. per ft 4. drilling to the large diameter of the taper 6-38. Which taper has the greatest included angle between opposite sides? 1. Brown and Sharpe taper 2. Milling machine taper Learning Objective: Identify the 3. Morse taper terminology associated with machine 4. Pipe taper threads. Textbook pages 9-8 through 9-10. 6-39. Which taper is commonly used on drill shanks? 1. Morse taper 2. Jarno taper 3. Brown and Sharpe taper 4. Pipe taper

6-40. What is the diameter of the small end of a No. 3 Morse taper? 1. 0.4 in. 2. 0.778 in. 3. 0.938 in. 600 4. 1.25 in. 0.125 6-41. What method is normally used to cut large angles of taper on short workpieces? 1. Taper-attachment method 2. Compound-rest method 3. Offset-center method 4. Simultaneous-feed method 0.0156 0.0156 6-42. What instrument is used to obtain 0.838 -44 accurate angular settings of the compound 0.919 rest? 1.000 1. Steel rule 2. Micrometer 3. Vernier bevel protractor Figure 6A 4. Center gage In answering items 6-46 through 6-48, 11 6-43. When a taper attachment is used with a refer to figure 6A. lathe, the oepth of cut is adjusted with the 6-46. What is the pitch ofthe screw thread 1. shoe clamp shown in figure OA? 2. crossfeed screw 1. 0.0625 in. 3. compound-rest feed screw 2. 0.125 in. 4. longitudinal feed screw 3. 0.162 in. 4. 0.919 in.

35

Aft., A.., 6-47. Which dimensions of the threi shown in 6-53. figure 6A are equal? Failure to set a threadingtool per- 1. Crest width and root. width pendicular to the work axisresults in an incorrect 2. Crest width and half pitch 1. 3. Crest diameter and root diameter pitch 2. 4. Root diameter and pitch diameter pitch diameter 3. helix angle 4. angle of thread 6-48. What is the major diameterof the thread shown in figure 6A? 1. 0.419 in. 2. 0.838 in. 3. 0.919 in. Learning Objective: Identify basic 4. 1.000 in. characteristics of the following threads: Acme, square, buttress, 0 Use the following information pipe, tapered pipe, and rtraight in answering pipe. item 6-49. Textbook pages 9-11through 9-14.

You desire to locate a bolt that has the 6-54. following characteristics: What is the depth ofan Acme thriNad that has a pitch of 0.25 inch? A. Nominal thread diameter ' = .75 inch 1. B. Threads per inch = 16 0.125 in. 2. 0.135 in. C. Series . American Nationalcoarse D. Class = 3 3. 0.260 in. 4. 0.510 in. 6-49 What is the thread designation? 6-55. What is the cutting edge 1. .75-ANC-16-3 width of a tool 2. 16-3-ANC-.75 used to cut square threads, 1/4-inch 3. 3-NC-3/4-16 pitch, on a screw? 1. 4. 3/4-16-NC-3 0.125 in. 2. 0.127 in. 3. 0.500 in. 4. 0.502 in. Learning Objective: Identify terms 6-56. What is the basic depth of and procedures associatedwith the a buttress thread which has 10 threads cutting of V-form threads. Textbook per inch? pages 9-10 and 9-11. 1. 0.07140 in. 2. 0.06627 in. 3. 0.03318 in. 4. 0.01631 in. 6-50. What information doyou need to cut a V-form screw thread? 6-57. Straight pipe threads 1. Pitch and width of the thread are usually used to join sections of pipe that 2. Straight depth of the thread will carry water to fire hoses. 3. Slant depth of the thread 4. All of the above

6-51. What is the slant depth ofan American Learning Objective: Identify thread Standard (external) threadhaving 10 threads per inch? measurement tools and theiruses. Textbook pages 9-'5 and 9-16. 1. 0.061343 in. 2. 0.0708 in. 3. 0.1000 in. 6-58. Which of the follnvins: 4. 0.6250 in. Lois is used to measure an internal :ltrei.d? 1. Thread ffirr)IneLvi: 6-52. Which instrument is usually used toset a 2, Plug gage threading tool true with the work? 3, Coin g 1. Bevel protractor 4. Adjnetable Collau 2. Screw pitch gage snap gage 3. Center gage 4. Thread dial indicator 6-59. The most accurate test of threads is 6-61. A very light cut is usually scribed on made by using which of the following the surface of work that is to be threaded tools? to provide a check on the accuracy of the 1. Thread micrometer 1. thread angle 2. Adjustable thread snap gage 2. root diameter 3. Go/no-go ring gage 3. pitch 4. Micrometer and three wires 4. crest width

6-62. The best lubricant for thread cutting in steel is lard oil. Learning Objective: Identify the procedures involved in cutting 6-63. What is ec.e most common chamfer used to threads on a lathe. Textbook pages finish the thread of a capscrew? 9-16 through 9-25. 1. 15° 2. 30° 3. 45° 6-60. The lead screw on your lathe has a pitch 4.' 60° of 10. If you want to cut a screw having 32 threads per inch, what must 6-64. Threads on a lathe workpiece are most be the ratio of the headstock spindle to easily terminated at a the lead screw? 1. drilled hole 2. shoulder 1. 3.2:1 3. groove 2. 4.0:1 4. milled slot 3. 1:3.2 4. 1:4.0

37 Assignment 7 Turret Lathes and Turret Lathe Operations; Milling Machines and Milling Machineperations Textbook Assignment: Pages 10-1 through 11-57

7-7. Which workholding device is commonly used to hold finish-bored Learning Objective: cylindrical Identify the work for finish turning or facing? basic components and workpiece set 1. Expanding plug arbor up procedurns for turret lathes. 2. Expanding bushing arbor Textbook pages 10-1 through 10-13. 3. Spring-type collet 4. Independent chuck 7-1. Due to a system of automatic stops, 7-8. A 4-jaw independent chuck requires cutting tools, once adjusted and sep- set arate adjustment of each jaw in order in motion, need no further attention to hold the work. from the operator.

7-2. What type of workpiece is usually Learning Objective: machined or a bar machine? Identify the procedures used to grind and install 1. Large-diameter casting cutting toils. 2. Textbook pages 10-14 Nonsymmetrical workpiece through 10-16. 3. Long stock 4. Workpiece that requires onlyone machining operat.,n 7-9. A coolant is normally used duringthe grinding of 7-3. On a ram-type turret lache, the tools 1. carbide cutters on the hexagonal turret are fed into 2. high-speed steel cutters the work by the movement of the 3. Stellite cutters 1. ram 4. carbide and Stellite cutters 2. cross-slide 3. saddle 7-10. Dipping a cutter blade in coolant 4. chuck during dry grinding causes the cutting edge to 7-4. On a turret lathe, the independent 1. soften carriage-stop adjustments for each 2. become brittle of the six positions are located on 3. crack the 4. warp 1. dial clips 2. feed rod 7-11. A groove is sometimes grouri along 3. stod roll the cutting edge on the top face of 4. stc rod a cutter bit to 1. minimize chatter 7-5. Metal 6,1.1 should be removed often 2. break up chips from the Dorking parts of turret lathes 3. produce a double chip with 4. reduce the strain on the point 1. comprci.sed air 2. a VJCUUM cleaner 7-12. What is the Preferred method of 3. a honlbruTh or r.ig con- trolling chip run-off from a cutter 4. a TuAnn,: bit? 1. Adjusttherake angles and feed 7-6. Spring- ynn F :t 4 !.-.11etti arc used 2. Groovethe on aCL:' ,1( top face of Phe cutter 3. Groovethe 1. vipp' front face of the cutter 4. Adjusttheclearance angles 2. holdinh -ylinderm 3. feeding bar str,, k 4. allolng any wur ere 7-13. The tip angles of a cutter must be 7-19. Which of the following forming cutters changed during regrinding if the can be used to quickly produce an odd- cutter is used in a or curved-shape? 1. rear tool post 1. Forged 2. square turret 2. Dovetail 3. rocker type tool holder 3. Circular 4. shim type tool holder 4. All of the above

7-14. On the hexagonal turret of a lathe, 7-20. On a turret lathe, the holder of a overhead turning cutters are centered dovetail forming cutter is mounted on the work with the aid of a on the 1. center gage 1. saddle or ram 2. spirit level 2. hexagonal turret 3. scale 3. cross-slide 4. plumb bob 4. square turret

Learning Objective: Identify the Learning Objective: Identify steps lathe attachments and procedures involved in cutting tapers and used for turning bar stock. Textbook threads. Textbook pages 10-21 pages 10-17 through 10-21. through 10-25.

7-15. The rollers that back up a bar turner 7-21. Solid adjustable and self-opening cutter are mounted on the dies are usually used for threading 1. square turret in preference to solid tools unless 2. hexagonal turret 1. high cutting speeds are required 3. reach-over tool post 2. machining time must be minimized 4. carriage 3. smoothly finished threads are required 7-16. Back rests without rollers are 4. very coarse cuts are taken usually used to back up bar turner cutters that are used on 7-22. When a turret lathe is used for 1. cast iron threading with a single-point tool, 2. mild steel angular cutter feed is usually used 3. brass for 4. aluminum 1. tapered threading cuts 2. roughing cuts 7-17. On stock machined in a bar turner, 3. finishing cuts which of the following conditions 4. roughing and finishing cuts on usually produces the smoothest straight or tapered work finish? 1. Light cut with the rolls ahead 7-23. On a turret lathe, the taper produced of the cutter by a taper attachment is determined by 2. Light cut with the rolls behind the setting of the the curter 1. automatic cross feed 3. Heavy cut with the rolls ahead of 2. guide plate the cutter 3. automatic longitudinal feed 4. Heavy cut with the rolls behtn 1 4. spindle speed the cutter 7-24. Assume that you are tooling a shoulder 7-18. When work is machined on a lathe, the stud on a turret lathe. The diameters stream of coolant should be applied of the shoulder stud have been turned. to the What is the next step in the operation? 1. tip of the tool 1. Cutting off the workpiece 2. surface of the work below the tool 2. Cutting the thread 3. surface of the work above the tool 3. Machining the radius on the end 4. shank of the tool of the workpiece 4. Forming the front diametrr 7-25. The tooling setup for small and medium 7-28. The power feed to the main head of a lot production of taper studs is almost vertical turret lathe permits identical. However, there is a 1. vertical movement of the main head difference in the way the taper is pro- 2. vertical and horizontal movements duced between small and medium lot of the main head production jobs. What is the difference? 3. vertical and diagonal movements of 1. In small lot production, the taper the main head is usually formed with a standard 4. vertical, horizontal, -fld diagonal wide cutter, and the taper is later movements of the main t.Ad ground to make the matched cuts accurate; in medium lot production, In answering items 7-29 through 7-31, the taper is turned with the cross- assume that you are preparing to cut slide taper attachment givingmore tapersusing a 30-inch Bullard vertical turret accuracy to the taper lathe. 2. In small lot production, thetaper is turned with the cross-slide 7-29. How many degrees in the direction ofthe taper attachment;I,. medium lot angle being turned do you swivel the production, the taper is usually main turret head in cutting a 53° formed with the standard wide cutter, taper? and the taper is later ground co 1. 16° make the matched cuts accurate 2. 32° 3. In small lot production, the taper 3. 47' is usually formed with a standard 4. 53° wide cutter, and the taper is later turned with a cross-slide taper 7-30. In cutting a 30° to 45° taper, you attachment; in medium lot production, swivel the main turret head ina the taper is formed with the cross- direction opposite that of the angle slide taper attachment alone being turned. 4. In small lot production, thetaper is formed with the cross-slidetaper 7-31. How many degrees do you swivel the main attachment, and the taper is later turret head in turning a 40° taper? ground to make the matched cuts 1. 50 accurate; in medium lot production, 2. 10° the taper is turned with the cross 3. 15° slide taper attachment, and the 4. 20° taper is later formed with a standard wide cutter to make the cross cuts more accurate Learning Objective: Describe the construction, uses, an: limitations of the three common types of knee Learning Objective: Identify basic and column milling machines used by terms and procedures associated with the Navy. Textbook pages 11-1 vertical turret lathes. Textbook through 11-6. pages 10-25 through 10-32.

7-32. When only one type of knee and column 7-26. Vertical turret lathes are particularly milling machine can be installed, what suitable for machining type will it usually be? 1. several workpieces simultaneously 1. Bed type 2. large, heavy workpieces 2. Vertical spindle type 3. nonsymmetrical workpieces 3. Universal type 4. small precision parts 4. Plain type

7-27. The main rails of a vertical turret 7-33. What feature distinguishes the universal lathe are perpendicular to the milling machine from the vertical spindle 1. side head and plain type? 2. feed rods 1. Three directions of table movement 3. upright bedways 2. The table swivels on the saddle 4. lead screw 3. More rig {d construction 4. Horizontal spindle axis

4O( -I 7-34. Which milling machine is most efficient for taking deep cuts at rapid rates of Learning Objective: Describe feed and speed? operations and applications of 1. Plain milling machine the principal milling machine 2. Universal milling machine attachments. Textbook pages 11-6 3. Universal milling machine with high- through 11-11. speed vertical milling attachment 4. Vertical spindle milling machine 7-42. Which vise may be used to mill work 7-35. Which movement is possible on a vertical at an angle in a horizontal plane? spindle milling machine but noton 1. Plain vise or universal vise other knee and column machines without 2. Swivel vise or universal vise the aid of an attachment? 3. Swivel vise or plain vise 1. Horizontal movement of the vertical 4. Universal vise, plain vise, or spindle swivel vise 2. Vertical movement of the vertical spindle 7-43. Which milling machine attachment 3. Vertical movement of the table would be good for holding stock which 4. Horizontal movement of the table is being made into a gear? 1. Swivel vise 7-36. To do a face milling job quickly, you 2. Universal vise should select 3. Dividing head 1. a plain milling machine 4. Center rest 2. a universal milling machine 3. a vertical spindle milling machine 7-44. How many turns of the crank of the 4. either a plain or universal milling worm shaft of a dividing head are machine required to rotate the spindle one revolution? 1. 20 Match the component in column A with the des- 2. 40 cription in column B 3. 60 4. 75 A. Component B. Description 7-45. Which milling machine attachment 7-37. Column 1. The support for allows you to machine the smallest the table and lead on a worm? 7-38. Knee saddle 1. Enclosed driving mechanism 2. Long and short lead attachment 7-39. Saddle 2. A movable support 3. Wide range divider to which the work- 4. Lbw lead driving mechanism 7-40. Table piece is fastened 7-46. Which milling machine attachmentper- 3. Used to position mits the greatest variation in the the work closer angle at which the cutter can be set? to, or farther 1. Universal milling attachment from the column 2. Compound vertical milling attach- ment 4. The principal 3. High-speed vertical milling support to which attachment the knee is 4. Circular milling attachment attached 7-47. Which milling machine attachment is used in cutting keyways? 7-41. The cutting tool of a milling machine 1. Compound vertical milling attachment is attached to what component(s)? 2. Circular milling attachment 1. A workholder 3. Slotting attachment 2. The overarm dovetails 4. Rack milling attachment 3. Aroor supports 4. The arbor Learning Objective: Perform plain indexing. Textbdok pages 11-12 through 11-16.

41 6 s 7-48. Rapid indexing is accomplished by using 7-54. Assume that you are to divide a piece of a/an work into 37 parts and your index angle 1. index head sector is given in minutes. Which index plate 2. direct index plate should be used if approximate divisions 3. universal dividing head are acceptable? 4. compound index plate 1. 11-hole plate 2. 15-hole plate 7-49. Eight complete turns of the index crank 3. 18-hole plate will move a universal dividing head 4. 23-hole plate spindle 1. 1/40 of a revolution 7-55. How far should you turn the index crank 2. 1/8 of a revolution on a 21-hole index plate to move the 3. 1/5 of a revolution circumference of the work 180 minutes? 4. 1/3 of a revolution 1. 3 holes 2. 6 holes 7-50. You are given a piece of work that is 3. 7 holes to be divided into 12 parts and you 4. 9 holes have a 24-hole index plate available. How far should you revolve the index crank on the index plate to make each Learning Objective: Perform division? differential indexing. 1. Textbook 1 complete turn and 3 holes pages 11-16 through 11-20. 2. 1 complete turn and 8 holes 3. 3 complete turns and 3 holes 4. 3 complete turns and 8 holes Information for items 7-56 and 7-57: Luu are differential indexing for 72 7-51. You are given a piece of work that is divisions. Your selected number is 70. to be divided into 960 parts andyou have a 24-hole index plate available. 7-56. How many holes in a 21-hole circle of How far should you revolve the index the index plate do you turn the index crank on the index plate to makeeach crank? division? 1. 2 1. 1 hole 2. 4 2. 2 holes 3. 8 3. 6 holes 4. 12 4. 12 holes 7-57. What is the ratio of the required 7-52. You are given a piece of work that is spindle gear to the required driven to be divided into 48 parts and you gear? have an 18-hole index plate available. 1. 1:2 How far should you revolve the index 2. 2:1 crank on the index plate tG make each 3. 7:8 division? 4. 8:7 1. 3 holes 2. 5 holes 7-58. Within the wide range divider, the 3. 13 holes revolution ratio of the small index 4. 15 holes crank superimposed on that of theworm wheel is such that the resulting 7-53. How far should you turn the index crank causes the dividing head spindle to on a 27-hole index plate to move the rotate at the rate of circumference of the work 110? 1. one turn to every one hundred turns 1. 1 turn and 2 holes of the large index crank 2. 1 turn and 4 holes 2. one turn to every four thousand 3. 1 turn and 6 holes turns of the small index crank 4. 1 turn and 8 holes 3. one hundred turns for each turn of the large index crank 4. foUr thousand turns for eachturn of the small index crank 7-62 Cutters with helical teeth are superior to cutters with straight teeth in which of the following ways? 1 1. They can take a wider cut

2. They produce a smooth, shaving . action 3. They reduce the shock produced when a cutter begins operation 4. They have all of the above advan- I0 4 tages

7-63. What type of cutter can be used in pairs to mill slots? 1. Half-side milling cuts

2. Side milling cutter . locking teeth 3. Metal slitting saw 4. Half-side milling k: .11 a metal slitting saw betw,c.k Figure 7A.-12-hole circle. 7-64. What kind of cutter is ground thinner In answering item 7-59, refer to toward its center to provide clearance figure 7A. between the cutter and the work? 1. Plain milling cutter 7 -59. What hole in the 12-hole circle should 2. Side milling cutter be covered by the right-hand arm of 3. Metal slitt.tns saw the index head sector if the required 4. Shell and mill number of holes for indexing is 5 and the index pin is inserted into hole 1? 7-65. Which of the following statements is 1. Hole 5 most accurate about the use of an 2. Hole 6 arbor with a solid end mill? 3. Hole 7 1. Use of an arbor is necessary, since 4. Hole 8 a solid end mill has no shank 2. Use of an arbor is not necessary, even though a solid end mill has no Learning Objective:Describe and c shank, since it is mounted on a explain the applications of the small central stud for use principal types of cutters. Textbook 3. Use of an arbor is not necessary, pages 11-20 through 11-35. since the cutter head can be at- tached to a shank 4. Use of an arbor is not necessary, 7-60. To what parts of a milling machine are since the body and shank of a cutters attached? solid end mill are one piece 1. A plain arbor or arbor yoke 2. A screw arbor 7-66. What kind of cutter is used for milling 3. A collet or adapter an enclosed space inside a slot? 4. An arbor or directly to the spindle 1. End mill 2. Metal slitting saw 7-61. The principal characteristic of plain 3. T-slot cutter milling cutters is that they 4. Dovetail cutter 1. have teeth on the circumference only 7-67. Woodruff keyseat cutters less than 2. have only straight teeth 1 1/2 inches in diameter are usually 3. always have helical teeth mounted on a/an 4. have teeth on the end only 1. arbor 2. permanent shank 3. stub arbor 4. arbor support

43 6%.7)() 7-68. What type of cutter can be manufactured Match the cutter or accessory in locally and can be made to column A with cut a the type of arbor in column B. variety of forms? 1. Fly cutter A. Accessory 2. Cornerrounding cutter B. Arbor 3. Convex cutter 7-71. Drill chuck 4. Gear hob 1. Taper adapter 7-72. Straight shank 7-69. The fastest cutting is done with 2. Fly cutter cutters drill having arbor 1. fine teeth and minimum diameter 7-73. Locally manu- 2. coarse teeth and minimum liameter 3. Stub arbor factured single- 3. fine teeth and maximum diameter point cutter 4. coarse teeth and maximum diameter 4. Cutter adapter

7-70. Fine-tooth cuttersare best ft.r 1. eliminating chatter when cutting heavy stock 2. milling at high speed 3. milling thin stock 4. producing a continuous ,:hip

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44 Assignment 8 Milling Machines and Milling Operations (continued) and Shapers, Planers and Engravers

Textbook Assignment: Pages 11-35 through 12-22

8-6. How large a hexagon can be cut from 1-inch round stock? Learning Objective: Describe the princi- 1. 0.707 inch ple of milling operations. Textbook 2. 0.866 inch pages 11-35 through 11-57. 3. 1.0 inch 4. 1.555 inches

8-1. In mounting a cutt.sr on an arbor, you 8-7. In milling a 3-inch hexagon, what is the replace the arbor nut on the arbor after minimum diLleter cylinder that you can the use? 1. draw-in bolt locking nut is inserted 1. 2.f', inches 2. cutter and arbor bearing are in place .2. 3.24 .r.,:hes 3. sae t1c is locked 3. 3.47 inches 4. afro, support is in place 4. 4.67 inches

8-2. In setting up a milling machine, how do 8-8. To mill a hexagon on the end of round you gage that the surface of the work stock, the work is positioned by using is just touching the teeth of the cutter? an index head. 1. Insert a thin feeler gage between the teeth of the cutter and the work 8-9. What attachment changes the rotary 2. Raise the work until the cutter stops motion of the spindle to a reciprocat- it,thenback off slightly ing motion? 3. Withthe cutter turning slowly, bring 1. Index head attachment the workup until it stops the cutter 2. Slitting saw attachment 4. With a piece of paper on the work 3. Slotting attachment surface, raise it until the rotating 4. Sawing attachment cutter pulls the paper

8-3. Face milling must be done with Match the material in column A with the type 1. shell end mills only of slitting saw in column B 2. face milling cutters onl, 3. the surface being mil'cd perTendicular A. Material B. Slitting Saw to the cutter axis 4. the feed of the work in the vertical 8-10. Fine tooth direction 1. Brass

8-4 When cutting a square on the end of a 8-11. Coarse tooth 2. Plastic piece of stock, what type of milling is used? 8-12. Staggered tooth 3. Thick steel 1. Climb milling 2. Up milling 4. Thin steel sheet 3. Climb milling when the stock is vertical and up mi'ling when the stock is horizontal 8-13. To obtain a hooked cutting face on a 4. Up milling when the stock is vertical tap, the flutes are cut with a and climb milling wher. the stock is 1. concave cutter horizontal 2. convex cutter 3. slitting saw 8-5. How large a square can be cut from a 4. fluting cutter piece of 1-inch round stock? 1. 1.414 .aches 2. 1.0 inch 3. 0.800 inch 4. 0.707 inch 8-14. Some straight reamer flutesare not cut at equal angles apart. Why is this Learning Objective: done? Apply appropriate factors to determine cutting speeds, 1. It gives a better cutting edge feeds, and coolants. 2. The angle of the flutes is not Textbook pages 11-60 through 11-64. important 3. It prevents chatter 4. For all of the above reasons 8-22. What will be the most immediate result of overheating a cutter? 8-15. When fly cutter is being used as a 1. A clogged cutter formed cutter, why should you rough 2. Worn machine gear out the surface with ordinary cutters? 3. Excessive vibration 1. To obtain a smoother surface 4. Dulled blades 2. To save time since the flycutter is not as fast 8-23. High-speed steel cutters can be operated 3. To reduce the load on the fly at higher speeds than carbon steel cutter arbor cutters because they have greater 4. For all of the above reasons 1. corrosion resistance 2. heat resistance 8-16. The cutting tools used for boring on 3. tensile strength a milling machine resemble what other 4. type of cutter? compression strength 1. End mill 8-24. What is the proper spindle 2. Shell end mill speed for a 3/4-inch cutter that is 3. Slot cutter tobe run at 65 fpm? 4. Fly cutter 1. 257 rpm 2. 306 rpm 8-17. The size of the hole being bored is 3. 331 rpm most easily and accurately adjusted in 4. 341 rpm what way? 1. By Oanging the bed position 8-25. What is the proper spindle speed 2. HyChanging the boring bar for a 3. 1/2-inch cutter that isto be run at 'Sy offsetting the boring bar 85 fpm? 4. By moving the cutter in the boring bar 1. 611 rpm 2. 649 rpm 3. 679 rpm Learning Objective: Identify common 4. 688 rpm milling machine attachments. Textbook pages 11-58 through 11-60. 8-26. What is the cutting speed ofa 1 1/4- inch cutter running at 140 rpm? 1. 43.2 fpm 2. 44.3 fpm Match the function in Column B with the type of 3. 45.8 fpm attachment in Column A. 4. 46.9 fpm A. Attachment B. Function 8-27. While a narrow slot was beingmilled, the cutter of the end mill 8-18. Tool maker's was broken. 1. Increases the What is the most likely knee reason for the speed of. rotation breakage? of the cutter 1. A deep cut was being taken with 8-19. Htgh speed uni- a high rate of feed versal attach- 2. Changes the direc- 2. ment The cutter was overheated tion of the cutter 3. The work was improperly supported axis to the verti- 4. A high rate of speedwas being used 8-20. Vertical milling cal position attachment together with a low rate of feed 3. Permits milling of 8-28. To mill a metal to a fine finish, 8-21. Circular milling you arcs and circles should use a attachment 1. high cutter speed anda slow feed 4. Permits milling rate compound angles 2. low cutter speed anda high feed rate 3. low cutter speed anda low feed rate 4. high cutter speed anda high feed rate

46 ... 8-29. What rate of speed and feed are best for 8-34. When you are using a horizontal boring roughing? mill equipped with a boring and facing 1. Low speed and low feed head, a continuous ratcheting sound will 2. Low speed and high feed warn you when 3. High speed and high feed 1. the feed is engaged and the slide 4. High speed and low feed is clamped 2. either the feed is engaged or the 8-30. Which metal should be machined without slide is clamped a liquid coolant? 3. the feed is disengaged 1. Brass 4. the slide is unlocked 2. Aluminum 3. Cast iron 8-35. What is the fastest slide feed rate 4. Nickel that can be set on a combination boring and facing head? 8-31. In milling with a periphery cutter, the 1. 0.005 inch per revolution flow of the coolant should be directed 2. 0.010 inch per revolution onto the 3. 0.050 inch per revolution 1. work 4. 0.100 inch per revolution 2. cutter 3. work and cutter 8-36. Machinery Repairmen aboard Navy repair 4. work, cutter, and spindle ships perform drilling and reaming operations differently on the radial drill than on the horizontal boring Learning Objective: Describe the oper- mill. ation of the horizontal boring mill. Textbook pages 11-64 through 11-72. 8-37. Which bearing area is labeled foryou to use as the reference point when aligning a split-sleeve bearing on a 8-32 Which of the following factors may be horizontal boring mill? used to determine the size of a hori- 1. Horizontal flange zontal boring mill? 2. Front face 1. Maximum thickness of work the table 3. Circumferential groove will hold 4. Lining 2. Maximum size boring and facing head that will fit on the spindle sleeve 8-38. You desire to cut a pipe thread to 3. Largest diameter flycutter it can certain design specifications. What accommodate mechanism on a horizontal boring mill 4. Largest diameter boring bar that should you adjust to achieve the the machine is designed to receive desired lead? 1. Cutter advance 8-33. When you set up a boring and facing 2. Gear train head, which of the following is a 3. Driving gear lever safety precaution to be followed 4. Feed clutch before shifting the spindle back-gear to neutral? 8-39. During a threading operation on a 1. Engage the spindle over-running horizontal boring mill, what happens clutch when you shift the thread lead lever 2. Shift the spindle back-gear to to standard position while making a neutral and adjust the spindle back- pass? gear 1. The feed stops 3. Extend the spindle of the boring 2. The feed clutch is disengaged and facing head from the sleeve 3. Thread timing is lost 4. Rotate the sleeve by jogging until 4. All of the above happen the heavy end of the facing head is down Learning Objective: Identify the basic parts and setup procedures for the shaper. Textbook pages 12-1 through 12-5.

47 8-40. The size of a shaper is determined by 9-47. To make an internal cut you use a/an the 1. left-hand toolholder 1. size of the cutter 2. gang toolholder 2. depth of the stroke 3. swivel head toolholder 3. size of the motor 4. extension toolholder 4. length of stroke 8-48. 8-41. Under which circumstance(s) is a Which mechanism is used to drive the shaper likely to chatter? ram of a crank shaper? 1. When the tool bit is not set 1. Hydraulic cylinder properly 2. Rack and spur gear 2. When the work is loose in the vise 3. Rocker arm assembly 3. When a formed cutter is in a left- 4. Pushrod and camshaft hand holder 4. In all of the above situations 8-42. What happens when you set the crankpin of a shaper offcenter? 8-49. What is the purpose of the gear shift 1. The rocker arm is prevented from lever? moving when you turn the crank gear 1. To change the rate of feed 2. The rocker arm moves when you turn 2. To change the speed of the motor the crank gear 3. To raise the worktable 3. The ram is positioned 4. To change the speed of the shaper 4. The table is positioned horizontally' 8-50. What percentage of the total machining 8-43. How should you change the direction time is accounted for by the cutting of feed on a shaper? stroke? 1. Adjust the feed connecting link 1. 502 2. Change the nut on the saddle 2. 60% 3. Lift and rotate the pawl on the 3. 70% table feed mechanism 1/2 turn 4. 802 4. Turn the feed screw 8-51. If the cutting speed in a shaping 8-44. What should you do to prevent the tool operation is 40 feet per minute and bit from digging into the workon the the length of stroke is 12 inches, return stroke of a vertical cut? what is the approximate number of 1. Fix a hooked tool in the toolhead strokes per minute? 2. Lower the work on the return stroke 1. 16 3. Raise the tool bit on the return 2. 20 stroke 3. 24 4 Swivel the clapper box to the side 4. 30

8-45. What is the function of shaper hold- 8-52. When you change from a carbon steel downs? tool bit to a high-speed steel tool 1. To hold small work in the vise bit, you multiply the cutting speed 2. To hold the ram'in position by a factor of 3. To lock the table in place 1. 1.5 4. To hold the tool bit in the tool- 2. 2.0 slide 3. 2.5 4. 3.0

Learning Objective: Perform compu- 8-53. When a rectangular block is being tations for and identify steps requir- shaped, which edge or surface is ed in performing basic shaper operations. shaped last? Textbook pages 12-5 through 12-13. 1. A face surface 2. A side edge 3. An end edge 8-46. You have to cut a large deep channel 4. Any of the above in a piece of steel and the channel will require machining on the bottom and 8-54. In shaping a rectangular block,you both sides. Which toolholder should insert paper strips between eachcorner you use? of the block and the parallelsto 1. Straight toolholder 1. test for firmness of seating 2. Swivel head toolholder 2. prevent scratching surfaces 3. Spring toolholder 3. prevent chipping corners 4. Extension toolholder 4. establish a clearance

48 8-55. You are cutting a keyway that extends 8-61. The columns on a planer are designed to part way up a shaft. What do you do to support the prevent the tool from binding at the end 1. work of the cutting stroke? 2. table 1. Use a special tool bit 3. gear train 2. Drill a hole at the end of the slot 4. crossrail 3. Allow the tool bit to free itself on the return stroke 8-62. The crossrail on a planer is designed 4. Raise the tool bit at the end of to hold the the cutting stroke 1. table 2. vise 8-56. What device is used to line up an 3. toolheads internal keyway in a gear with the axis 4. column of the gear? 1. Micrometer 8-63. How should you compensate for normal 2. Feeler gage wear on a planer? 3. Calipers 1. Use heavier oil 4. Dial indicator 2. Install shims 3. Adjust the gibs 8-57. When you are machining an irregular 4. Install new lead screws surface on a shaper, how do you move the cutting tool? 8-64. What mot!.ons are controlled by the 1. Horizontally, by hand or power feed crossrail feed box? 2. Horizontally, by hand 1. Vertical movement of the crossrail 3. Vertically, by hand or power feed 2. Horizontal movement of the toolhead 4. Vertically, by hand 3. Vertical movement of the toolhead 4. Both 2 and 3 above 8-58. In rough cutting a rack tooth, when do you lock the graduated collar on the 8-65. A planer is making a series of horizon- toolslide feed screw of the shaper? tal cuts on a piece of metal. What 1. After you start the shaper would you do to stop temporarily only 2. After the tool has been brought the crossfeed of the tool bit? into contact with the work 1. Shut off the electricity 3. Before the work is clamped to the 2. Move the start-stop range selector vice or table to the off position 4. Before you set the graduated dial 3. Move -he directional feed control on the crossfeed screw to zero to the neutral position 4. Disengage the horizontal feed 8-59. What should you do first to rough out clutch a piece that will have concave radii? 1. Control by hand the feed on all the rough cuts Learning 01,jective: Identify parts 2. Use automatic feed !, make a series and operrcirg proLedares of the of horizontal cuts pantograph. Textbook pages 12-18 3. Use automatic feed to make a series throue. ]2. of vertical cuts 4. Set the horizontal and vertical feed to give the proper contour 8-66. What point should you check to deter- mine if a pantograph is level? 1. Spindle Learning Objective: Identify parts 2. Copyholder of planers and steps involved in 3. Worktable planer operation. Textbook pages 4. Support base 12-14 through 12-17. 8-67. On which arm of the pantograph is the tracing stylus attached? 8-60. The size of a planer is designated 1. Tracer arm according to the 2. Upper bar 1. length of stroke 3. Lower bar 2. size of the work which it will 4. Connecting link accommodate 3. size of the motor 4. length of the bed

49 (I,

Ar: 8-68. The blocks are set on the pantograph 8-72. What is the reduction if length of bars according to the copy is 1.8 inches and the length of the 1. spindle speed desired finished job is 1.2 inches? 2. size of the copy 1. 0.6 3. size of the finished work 2. 1.5 4. reduction desired 3. 2.2 4. 3.0 8-69. What is the highest spindle speed obtainable on a model 3-U pantograph? 8-73. Cutter speed on a pantograph is affected 1. 5,000 rpm by which of the following factors? 2. 10,000 rpm 1. Depth of cut 3. 15,000 rpm 2. Rate of feed 4. 20,000 rpm 3. Type of material being cut 4. All of the above 8-70. On a model 3-U pantograph, how isthe spindle speed adjusted? 8-74. In general, which of the following 1. By varying the voltage materials requires the slowest operation 2. By using the gear shift of the cutter on a pantograph? 3. By adjusting the drive belts 1. 4. By using the flow control lever 2. Cast iron 3. Hard bronze 8-71. On the copyholder of a pantograph, what 4. Hardened alloy steel is the main purpose of thestop screws? 1. To keep the pantograph arms from going too far 2. To keep the cutter from goingtoo far 3. To hold the work in the copyholder 4. To align the copy with the table

50 Assignment 9 Shapers, Planers and Engravers (continued) and PrecisionGrinding Machines and Metal Buildup

Textbook Assignment: Pages 12-22 through 14-12

9-5. Three- or four-sided cutters are normally used for engraving on Learning Objective: Identify the tech- 1. large, heavy work nology associated with, and the steps 2. very soft work involved in grinding pantograph cutters. 3. small steel pieces Textbook pages 12-22 through 12-29. 4. wood

9-1 When do you rotate a conical point Learning Objective: Identify special against a grinding wheel? purpose accessories for the pantograph 1. When rough grinding and how those accessories are used. 2. When grinding chip clearance Textbook pages 12-30 through 12-33. 3. When grinding flat to center 4. When grinding away stock on the clearance angle 9-6. A concave forming guide may be used for engraving on which of the following 9-2 What is the main purpose in tipping off shapes of workpieces? a cutter point? 1. Flat 1. To increase the life of the cutter's 2. Concave sharpness 3. Convex 2. To obtain special effects when 4. All of the above engraving 3. To remove the burr 9-7. To what part of a pantograph is the 4. To save grinding any clearance forming guide attached? 1. Copyholder 2. Worktable 3. Forming bar 4. Vertical feed control

9-8 When you use a circular copy plate to engrave various single letters on a number of similar workpieces, you must align worktable, copyholder, and align- ing stops for each workpiece.

9-9 When engraving a dial face that hss 10 graduations, how many degrees will you rotate the rotary table bAtween cuts? 1. 36° Figure 9A. 2. 45° 3. 60° 9-3. What name is usually given to the indi- 4. 72° cated angle in figure 9A? 1. Clearance angle 2. Rake angle Learning Objective: Select or deter- 3. Cutting angle mine the appropriate grinding wheel 4. Relief angle speeds, feeds, and coolants for specified situations. Textbook pages 9-4. What determines the size of the indicated 13-1 through 13-4. angle in figure 9A? 1. Spindle speed 2. Size of the cutter 3. Material to be cut 4. Size of the copy

51 wheel speed is most common iu 9-18. How does the cross traverse table vrecicion grinding? on the grinding machine shown in figure 13-3 1,000 to 2,000 fpm of your textbook move in relation 2. 3,000 to 4,000 fpm to the wheel evindle for each stroke of 3. 5,500 to 9,500 fpm the slicing table? 4. 9,500 to 10,500 fpm 1. It moves a direction parallel to the Ep1m11-, with a feed slightly 9-11. What is the surface speed ofagrinding wheel that hLo a circumference less than .';e thickness of the of 1p grinding inches and is set an a spindle whose 2. It :Infes in a direction perpendic- speed is 4,000 rpm? ular tc the spindle with 1. 4,500 fpm a feed 2. 6,000 fpm equal to the diameter of thegrind- ing wheel 3. 7,500 fpm 3. It moves ia a cirection parallel 4. 10,000 fpm to the spindle with a feed equal 9-12. In mast cases, a speed less to the thickness of the workpiece than the 4. It moves in a direction perpendic- speed indicated on a grinding wheel is ular to the spindle with the most effective cutting speed. a feed to the thickness of the grin6ing wheel 9-13. Which of the following effectsindicates that the grinding wheel is rotating too 9-19. slowly? How does the sliding tableon the grinding mechinr shown in figure 13-3 1. Wheel surface wears too fast of your textbook move in 2. Wheel slides over the work relation to the wheel spindle? 3. Work overheats 1. 4. All of the above effects It moves at right angles to the rpindle with a feed short enough to prevent the workpiece from 9-14. Rust formation on machine partspro- hibits the use of plain water clearing the grinding wheel as a 2. It moves at right angles grinding coolant. to the spindle with a feed long enough 9-15. Which of the following to allow the workpiece to clear characteristics the grinding wheel is not desirable ina cutting fluid? 3. It moves in a direction parallel 1. High cooling capacity 2. High viscosity to the spindle with a feed short 3. Low flammability enough to prevent the workpiece from clearing the grinding 4. Noncorrosiveness wheel 4. It moves in a directionparallel to the spindle with a feed long Learning Objective: enough tr allow the workpieceto Identify the clear the grinding wheel major parts of the surfacegrinder and state the use(s) of each part. 9-20. Both the cross traverse and Textbook pages 13-4 through the slid- 13-8. ing table on the grinding machine shown in figure 13-3 ofyour textbook may have the distances of their 9-16. The wheelhead motor of the surface strokes adjusted and may be manually grinder shown in figure 13-3 ofyour operated. textbook is located in the base of 9-Ll. To alter the depth of the grinder. cut on a work- piece being ground on the grinding 9-i7. In operating the surface grinder machine shown in figure 13-3 ofyour shown textbook, you have to adjust in figure 13-3 of your textbook, the you height of the position of the have to stop the hydraulicmotor in workpiece. order to stop the traverse tables. 9-22. Which condition is NOT esskntialto holding work in place ina grinding machine equipped withan electromag- netic chuck? 1. The control lever must bein the ON position 2. Work must be made of ferrousmetal 3. Work must be in contactwith two poleb of the chuck 4. The chuck must be equippedwith a demagnetizer 9-23. To finish grind a piece of hardened steel that you have just rough ground, Learning Objective: the longitudinal traverse speed of the Identify the basic parts and set up procedures worktable should be of the tool and cutter grinder. 1. increased from 10 fpm to 25 fpm Text- book pages 13-10 2. increased from 25 fpm to 40 fpm through 13-15. 3. decreased from 40 fpm to 25 fpm 4. decreased from 60 fpm to 40 fpm 9-29. Grinding wheels can be mountedon both ends of the spindle on the 9-24. What is the purpose of rough wheelhead grinding of a tool and cutter grinder. a single-point tool bit on a bench grinder before setting the toolbit in 9-30. a jig for finish grinding? Suppose that you are to grinda milling 1. To save time cutter with the tool and cutter grinder shown in figure 13-8. 2. To increase cutting accuracy Which of the following combinations of 3. To lessen chances of heat distortion devices do you use to hold the cutter on the 4. To lessen stress on finishing wheel grinder? 1. Workhead and footstock 2. Learning Objective: Sliding table and taper table Identify basic 3. parts and operating procedures Taper table and tooth rest 4. associated with cylindrical grinders. Wheelhead and tooth rest Textbook pages 13-8 through 13-10. 9-31. Which features of a tool andcutter grinder make it possible fora 9-25. Machinery Repairman torun the machine Which component of a surface grinderis NOT found on a cylindrical grinder? while standing at themost favorable 1. Coolant system position for seeing the work? 1. 2. Hydraulic power unit A left-hand footstock anda right- hand footstock 3. Cross traverse table 2. 4. Wheelhead A control handwheel at thefront of the grinder and anotherat the 9-26. The platen on the cylindrical grinder back it 3. permits an operator to A column-mounted wheelheadand a 1. double-ended spindle feed the grinding wheel into the 4. work A taper table and a slidingtable, used together 2. slide the table back and forthacross the face of the grinding wheel 9-32. A cutter is considered dull 3. move the grinding wheel above or and in need of sharpening when below the center of the work 1. the primary lands are 4. swivel the grinding wheel worn and rounded 2. the primary lands become 9-27. On a cylindrical grinder, the distance more than 0.035 inch wide of longitudinal traverseper revolution 3. the wear lands become less of the workpiece is equalto than 1. 0.010 inch wide a distance slightly less than wheel 4. thickness the wear lands becomemore than 2. the length of the workpiece 0.010 inch wide 3. the width of the workpiece 9-33. What can you do to correct 4. the diameter of the grinding wheel a situation in which the grinding wheelbegins to 9-28. In setting up work on a cylindrical burr the cutting edge ofa cutter you arc grinding? grinder, when do you start the coolant 1. flow? Have the grinding wheelrotate 1. When you begin grinding the work towatd the cutting edge 2. Reduce the grinding speed 2. Just before you dress the wheel 3. 3. After you have made a cleanup Increase the grinding speed cut 4. 4. As soon as you start the spindle Decrease the feed motor and hydraulic pump 9-.-Ja. Assume that you are grinding a stagger tooth milling cutter. Which of the following steps should you perform first? 1. Align the wheelhead axis with the footstock centers 2. Bring one cutter tooth in contact with the tooth rest blade 3. Bring one cutter tooth in contact Figure 9B. with the wheel 4. Swing the master electrical switch 9-34. Vaich of the following types of cutters to ON should b. Sharpened by using the blade shmin in figure 9B? 9-39. When you sharpen the peripheral teeth on 1. Straight-fluted reamer an end mill using a grinder, it will be 2. Helical tooth cutters necessary to change or remove the 3. Side milling cutters cutter's size markings. 4. Straight tooth plain milling cutter 9-40. To prevent rapid dulling of cutting 9-35. To grind a cutte requiring a 5° edges, the corners of the teeth on an clearance angle, how much should you end mill are ground with a 45° corner raise a 6-inch diameter straight wheel angle. head? 1. 0.002 inch 9-41. Which part of an involute gear cutter's 2. 0.026 inch tooth must be ground before you can 3. 0.250 inch sharpen the actual cutting surface? 4. 0.261 inch 1. Face 2. Back 3. Corner Learning Objective: Identify the 4. Periphery terminology and procedures associated with the grinding of cutters, mills 9-42. A formed cutter may be sharpened and taps. Textbook pages 13-15 while set up between centers on a through 13-22. mandrel in the same manner as for sharpening a/an 1. plain milling cutter 9-36. What occurs when you sharpen a plain 2. stagger tooth cutter milling cutter with helical teeth 3. end mill cutter using a cup type wheel head when the 4. angular cutter wheel head is swiveled to 89°? 1. Maximum compensation for wheel wear is accomplished Learning Objective: Identify 2. The wheel head axis is positioned characteristics of proper honing in the same horizontal plane as operations. Textbook pages 13-22 the axis of the footstock centers through 13-24. 3. The end of the cutter clears.the opposite cutting face 4. The end of the cutter does not 9-43. Which of the following polished sur- clear the opposite cutting face faces is/are the result of honing? 1. The insid,. of a cylinder 9-37 While you are sharpening a milling 2. The cutting edges of a reamer cutter on a grinding wheel, the gradual 3. The surface of a magnetic chuck wearing down of the wheel grinding sur- 4. The teeth of an end cutting mill face will cause inconsistencies among the various cutting teeth. How can you 9-44. What pattern should you see on a prevent this effect? properly honed surface? 1. Proportionately increase grinding 1. Ovals pressure from one tooth to the next 2. Circles 2. Use a cutting fluid or paste com- 3. Straight lines pound 4. Crosshatch lines 3. Alternate the grinding process by rotating the cutter 180° after com- pleting each revolution 4. Rotate the cutter 90° for each com- plete revolution Learning Objective: Identify the Learning Objective: Identify the capabilities of the spray metaliz- procedures to be followed in pre- ing process. Textbook pages 14-1 paring metal surfaces for spray through 14-4. metalizing. Textbook pages 14-4 through 14-7.

9-45 What is the basic principle ofspray metalizing? 9-50. What are the major steps in preparing 1. Spraying powdered metal on a a surface to receive a metal spray melted surface coating? 2. Spraying melted droplets of metal 1. Cleaning and surface roughening on a surface 2. Cleaning and undercoating 3. Coating the metallic surface with 3. Cleaning, undercutting and sur- a metallic spray paint face roughening 4. Wiping a heated metal surface with 4. Surface roughening, undercutting, metallic alloys having a low melting and polishing point 9-51. A shaft is to be restored by under- 9-46. Which of the following is a common cutting a worn section and building purpose of spray metalizing to form up with sprayed metal. a hard surface? Before it is roughened by abrasive blasting, which 1. Plating objects to improve weather of the following operations must be resistance done? 2. Increasing the tensile strength 1. Washing with solvent of a machine part 2. Undercutting 3. Creating a wear-resistant bearing 3. Cleaning by vapor degreasing atrface 4. Both cleaning and undercutting 4. Improving the appearance of cast metal objects 9-52. When heat cleaning is used on porous steel castings which have been 9-47. What two thermal spray processes con- are talinated with oily deposits, they most likely to be used by an MR 3 or should be heated to what temperature? MR 2? 1. 650°F 1. Wire oxygen-fuel spray and wire- 2. 550°F consumable electrode spray 3. 300°F 2. Plasma-arc spray and powderoxygen- 4. 200°F fuel spray 3. Wire-consumable electrode spray 9-53. When preparing a shaft for restoration, and plasma-arc spray you should finish the ends of the 4. Powder oxygen-fuel spray and wire undercut section in what way(s)? oxygen-fuel spray 1. Weld them 2. Braze them 9-48. Which of the following safety pre- 3. Chamfer or straight cut them cautions is applicable to the use of 4. Fillet them the cleaning solvents used in pre- paring metal surfaces for spray 9-54. When machining an undercut on a shaft, metalizing? how do you determine what length isto 1. Provision for adequate ventilation be undercut? 2. Wearing of an approved respirator 1. It is a multiple of the diameter 3. Use of a face shield of the shaft 4. Wearing of glores and protective 2. It is no more than the length of clothing the work area 3. It depends on the amount of 9-49. wear Exothermic coatings can be applied by anticipated which of these processes? 4. It depends on the length of the 1. Powder oxygen-fuel spray bearing or packing in which that 2. Wire oxygen-fuel spray section of the shaft will run

9-55. In preparing a surface for spray metal- izing, you should undercut toa depth at least equal to the recommended min- imum thickness for the particular coating plus the wear tolerance.

55 fl4 9-56. The abrasive blasting used for surface 9-62. If you are using a gas flame to preheat preparation should produce what desired work, you should avoid directing the degree of roughness? flame direztly onto that part of the 1. 100-200 microinches work which is to be sprayed. 2. 200-300 microinches 3. 300-400 microinches 9-63. If the surface being sprayed is too 4. 400-500 microinches cool, the sprayed metal may crack or not bond. If the surface is too hot, 9-57. When using suction equipment during either the tempar of the base metal abrasive blasting operations, you will be lost or the deposit will be should place the nozzle how far from unsatisfactory. Within what tempera- the work? ture range should the base metal be 1. 1 to 2 inches while being sprayed? 2. 2 to 4 inches 1. 50° to 250°F 3. 3 to 6 inches 2. 60° to 350°F 4. 6 to 12 inches 3. 70° to 450°F 4. 200° to 500°F 9-58. Having started abrasive blasting a surface, you pause and place a drop 9-64. If macroroughening (the cutting of of cleaning solvent on the freshly fine grooves in the work with a lathe) blasted surface. What are you look- has been used to prepare the surface, ing for? the stream of spray metal for the first 1. A da7k ring which indicate; oil few layers should be directed at an in the compressed air angle of 2. An oily smudge that indicat's the 1. 45° to the work axis part has not been completely 2. 50° to the work axis degreased 3. 55° to the work axis 3. Traces of the blasting grit being 4. 60° to the work axis embedded in the surface 4. All of the above 9-65. When the work is to be machined to its final dimension, what minimum amount 9-59. In abrasive blasting, what masking of excess spray should be applied? material will work best? 1. 0.003 inch 1. Aluminuny. 2. 0.004 inch 2. Paler tape 3. 0.005 inch 3. Electrical tape 4. 0.008 inch 4. Rubber 9-66. On completion of spraying the shaft, 9-60. After you have completed preparation how should you cool the work? of a surface, you should begin the 1. Quench it with water spraying operation within 2. Quench it with oil 1. 1 hour 3. Quench it with brine 2. 2 hours 4. Allow it to set at room temperature 3. 3 hours 4. 4 hours 9-67. If severe.conditions are anticipated during the service life of the surface, when are sealants applied to the metal- Learning Objective: Describe the ized surface? procedures for spray metalizing 1. Between the spraying and machining using the fuel-oxygen methods. operations Textbook pages 14-7 and 14-8. 2. After the machining operation 3. At either or both of the above times 9-61. rrior to applying metal spray, you 4. Befm-e the last layer of spray is should ensure the work is free of deposited moisture by preheating it to 1. 6L° to 80°F 9-68. What material(s) should be used to mask 2. 100° to i50°F against sprayed metal? 3. 200° to 2i.5*F 1. Common masking tape 4. 250° to 300°F 2. A high temperature resisting masking tape 3. A special liquid masking compound 4. Both 2 and 3 above

56 9-70. Which of the following techniques is Learning Objective: Identify special NOT suitable for finishing sprayed problems involved in machining and metal surfaces? finishing thermal sprayed metal 1. High work speed deposits. Textbook pages 14-8 2. Light cuts through 14-12. 3. High grinding wheel speed 4. Slow feed or traverse of the cut

9-69. Which of the following equipment is NOT 9-71. What is achieved by applying sealer to suitable for finishing sprayed metals? a sprayed surface of a journal bearing 1. Soft, coarse grinding wheels before grinding it? 2. Dry grinding wheels 1. The metal will not clog the wheel 3. Carbide tools 2. The metal will cut more cleanly 4. Clean coolants 3. Abrasive is kept out of the pores of the sprayed metal 4. Both 2 and 3 above Assignment 10

Metal Buildup (Continued)

Textbook Assignment: Pages 14-12 through 14-67

10-6. What is/are the function(s) of the covering on the contact plating tool? Learning Objective: Identify the 1. To prolong tool life equipment and materials used in 2. To facilitate plating flat areas contact electroplating. Textbook 3. To soak up and dispense the plati.g pages 14-12 through 14-16. solution 4. To do all of the above

10-1. Since it provides corrosion and wear 10-7. Which of the following is NOT an resistance and can be used to build important operator function of the up worn areas on machine parts, contact plating process? contact electroplating has replaced 1. Prepariag the surface to be plated the older system of bath plating. 2. Maintaining the power pack unit 3. Determining proper power settings for 10-2. The most commonly used electroplating the job to be done power packs have what output? 4. Using proper to hnic to apply the 1. 60to 100 amperes a.c. plating 2. 25to100 amperes a.c. or d.c. 3. 25to100 amperes d.c. 4. 60to100 amperes a.c. or d.c. Learning Objective: Identify the 10-1. A contact plating tool consists of an hazards associated with plating insulated handle with a conductive core solutions. Textbook pages 14-16 and an anode made of and 14-17. 1. an iridium-platinum alloy 2. graphite or high quality carbon 3. either a high quality graphite or an 10-8. Contact plating solutions are hazardous iridium-platinum alloy in which, if any, of the following ways? 4. conductive graphite with cooling fins 1. Irritating to the eves 2. Toxic and poisonous 10-4. What three types of solutions are used 3. Both 1 and 2 above for contact plating and related opera- 4. They are not toxic, but may stain tions? the skin 1. Cleaning, activating, and plating 2. Preparatory, plating, and stripping 10-9 Contact plating solutions and the vapors 3. Plating, stripping, and activating produced during the plating operationsare 4. Stripping, cleaning, and activating irritating to the eyes and skin but are not dangerous to the respiratory system. 10-5. In what way i contact plating solution applied to the work? 1. Dipped from a shallow dish 2. Brushed on the work Learning Objective: Interpret and 3. Poured on the work apply technical terms used in 4. The work is dipped in the solution describing the plating process. Textbook pages 14-17 through14-21.

58

f;I4 ,) In items 10-10 and 10-11, match the operation 10-18. What application of contact plating has in column A with the condition in column B. been the most successful and can be done with the least restriction? A. Operation B. Condition 1. Class I 2. Class II 10-10. Activating 1. Forward current; the 3. Class III work is the cathode 4. Class IV 10-11. Plating

2. Forward current; the 10-19. Which of the following products ofa anode is the cathode plating operation would be Class V? 1. A rubbing-contact part for galley 3. Reverse current; the equipment work is the cathode 2. A rubbing-contact part for a main propulsion turbine 4. Reverse current; the 3. Chrome-plated shell casings to anode 13 the cathode decorate the quarterdeck 4. A component of nuclear power propulsion machinery 10-12. In the electrical circuit used for plating the ions of the plating 10-20. Restoring surfaces by contact plating solution flow away from the anode and must be approved by NAVSEA in which of toward the cathode. the following cases? 1. Repairing steam cuts in a steam 10-13. Anodic corrosion protection is provided turbine casing flange by a deposit of reactive metal on 2. Repairing a steam turbine rotor noble metal. journal bearing 3. Improving sealing surfaces on wave 10-14. Sacrificial corrosion protection is guides provided by the same means as cathodic 4. All of the above corrosion protection.

10-15. Carburizing, hydrogen embrittlement, and nitriding ate all similar processes Learning Objective: Identify used to surfaceharden light alloys. applications which are not suitable for contact plating or which require special techniques. In items 10-16 and 10-17, match the electrical Textbook pages 14-22 and 14-23. term in column A with the characteristic of water flowing in a pipe in column B. 10-21. Plating is an effective way to repair B. Characteristic small cracks (not in excess of 1/2 inch in length). of water flowing A. Electricnl_Term in n pipe 10-22. How can additional layers of chromium 10-16. Ampere 1. Velocity of the be plated over an existing bath chromium deposit? flow 10-17. Volt 1. By completely removing the bath 2. Volume flowing chromium deponit 2. By firnt acid cleaning the surface of the bath 3. Pressure of the water 3. By first plating the bath chromium with nickel 4. By using normal surface preparation 4. Internal resin- tance of the of the bath chromium Pipe 10-23.Why 18 contact platingwith chromium to build up worn parts NOT recommended? Learning Objective: Cite Lypical 1. Other metals will do the job better applications of contact plating. 2. Thick chromium lnyern do not work Textbonk pages 14-21 and 14-27- well ------3. Contact plated chromium in not as - hard na bath plated chromium 4. For all of the above reasons 10-24. To restore a wear-resistant surface 10-30. When plating is inspected using where an extensive buildup is needed, Group I liquid penetrant, the indication shall you should deposit a layer of hard NOT exceed what amount? metal such as cobalt on a base of 1. 1/64 in. 1. nickel 2. 1/32 in. 2. cobalt-tungsten 3. 1/16 in. 3. copper 4. 1/8 in'. 4. chromium

Learning Objective: Identify the Learning Objective: Identify components and describe the general documentation associated with operation of the contact plating contact plating operations. Text- power pack. Textbook pages 14-25 book pages 14-23 and 14-24. through 14-27.

10-25. If a plating solution does not perform 10-31. What is the principal function of. the according to its specifications, you ammeter on the power pack? should notify the Nival Ship's 1. To indicate plating rate Engineering Center, and they will 2. To avoid overloading the pack notify the manufacturer. 3. To measure the thickness of deposit 4. To set the proper plating rate 10-26. As a quality control measure, liquid penetrant testing is used to check 10-32. To determine how much of a total 1. surfaces before plating plating operation has been completed, 2. flange surfaces you should observe the 3. all hard surfaces 1. ammeter 4. sliding contact bearing surfaces 2. voltmeter 3. volts control knob 10-27. Which of the following information 4. ampere-hour meter about a plating job is NOT part of the engineering and job planning function? 10-33. The rate at which plating willoccur is 1. Method of surface finishing controlled by the 2. Name of the ship that ordered the 1. reset button lob 2. volts control knob 3. Types of metals in the base and 3. ampere-hour meter used for plating 4. circuit breakers 4. Finished thickness of the deposit 10-34. Which of the following guidelines applies to the connecting of the plating Learning Objective: Describe the tool leads? principal inspections and tests 1. Always connected to n terminal of used to check the quality of the opposite color contact plating. Textbook page 2. .Large size lends are always connected 14-25. to the black terminal 3. Usually connected to the black terminal 10-28. A burned portion of plating has what 4. Color and size of leads must he appearance? compatible with the terminal to 1. Blistered which attached 2. Pitted 3. Coarse grained 10-35. You are going to plate a part with 4. bark blue .-Ad pitted nickel solution 2080 and desirea contact area of 16 square inches for 10-29. Inspection if the qualhfy of a deposit the tool. What rating (from Table 14-3) intended to: rubbing )ntact service power pack should you select? includes which of tilt following tests? 1. 30-25 1. Liquid penetrant 2. 60-35 2. Visual 3. 100-40 3. Adhesion 4. 140-40 4. All of the above

f'i

60 10-41. To plate an area of 40 sq in. toa depth Laming Objective: Select and of 0.003 in. with a solution of Nickel n .pare plating tools. Textbook code 2080, how many ampere-hours are ?an,s 14-27 through 14-33. required? 1. 12.6 amp -hr. 2. 25.2 amp-hr 10-36 Tools used in the cleaning, deoxidizing, 3. 29 amp-hr and etching steps do not have to meet 4. 36.2 amp-hr the requirements of plating tools. However, they should meet what minimum Use the following information in contact area requirements? answering question 10-42. 1. Contact 10% of the area 2. Contact 30% of the area You are using nickel 2080 to plate an 3. Contact 10% of the length of the area of 40 sq in. From Table 14-7 you area determine that ACD is 6. Your power 4. Contact 30% of the length of the pack is rated at 100 amperes. The area depth of plating is to be 0.003 in. and 25.2 amp-hr plating current is required. 10-37. The importance of selecting the proper Your plating tool has a contact area of plating tool is greatest when which of 17 sq in. the following factors is present? 10-42. 1. Thin plating on a small area About how much time can be saved by 2. Thick plating or a small area using a solution-fed tool? 3. Thick plating on a large area 1. 0.105 hr 4. Thin plating on a large area 2. 0.240 hr 3. 0.247 hr 10-38. You are using solution 2080 with a 4. 0.252 hr 100-40 power pack. What is the optimum 10-43. (maximum) contact area? (Use Table If a 150-40 power pack is used to plate 14-3.) the bearing area of a shaft that has a 1. 5 sq in. total surface area of 40 sq in., what 2. 10 sq in. is the maximum practical contact area? 1. 3. 17 iq in. 40 sq in. 4. 25 sq in. 2. 20 sq in. 3. 17 sq in. 10-39. You must design a special plating tool 4. It depends on the length of the using Formula 3 on page 14-66 of the contact area text. Using solution 2080, you find 10-44. in Table 14-7 that the average current You are to plate a cylindrical outside density (ACD) is 6. Your power pack diameter surface that has a length of 4 is rated at 100 amps. What is the inches and a circumference of 10 inched. optimum contact area? You will use plating solution and equip- 1. 16 2/3 sq in. ment requiring an optimum contact area 2. 18 1/2 sq in. of 17 sq in. What should be the 3. 25 sq in. dimensions of the tool's (A) length And 4. 60 sq in. (B) internal arc? 1. (A) 4 in. (B) 10 in. 10-40. Which of the following is NOT an 2. (A) 4 in. (B) 5 in. advantage of a solution-fed tool? 3. (A) 4 in. (B) 4 1/4 in. 4. (A) 3 1/4 in. 1. Cooler anodes (B) 5 in. 2. Faster plating rate 3. Less solution required 4. Ensures more fresh solution Learning Objective: Identify available on the plating surface procedures for ensuring the use of clean anodes for plating opera- tions, and describe procedures for In answering item 10-41, use Formula 1 on page 14-65. covering anodes. Textbook pages 14-34 through 1.4 -40. 10-45. That is the best way to be sure an 10-51. When wrapping the anodes for plating anode is NOT contaminated with one inside or outside diameters, about what solution before being used with total thickness of cotton batting is another? desired? 1. Use one tool for preparatory 1. 1/16 in. operations and another for plating 2. 3/32 in. 2. Scrape and wash all anodes after use 3. 2/16 in. 3. Scrape and wash plating anodes 4. 3/16 in. before use 4. Identify specific anodes foruse with specific solutions Learning Objective: Identify general procedures for storing 10-46. What is the relationship between initial plating solutions. Textbook page covers and final covers? 14-41. 1. The final covers protect the initial covers 2. Final covers are used only for 10-52. Contact plating solutions should be finishing work stored at room temperature andaway 3. Initial covers can be used by them- from light. selves, hat final covers must be used wish initial covers 10-53. If solid crystals precipitate out ofa 4. The final cover is the one that plating solution and form on the bottom distributes 'Ile solution over the of the container, the solution always contact area must be discarded.

10-47. What is the most commonly used final 10-54. What information is kept in a log to cover? indicate how heavily the solution has 1. Dacron batting been used? 2. Cotton batting 1. The specific gravity of the solution 3. Dacron tubegauze 2. The number of times the solution 4. Cotton tubegauze has been used 3. The amount of electrical currant that 10-48. What is the most commonly used initial has passed through the solution cover? 4. The percentage of dilution of the 1. Dacron batting solution 2. Cotton batting 3. Dacron tubegauze 4. Cotton tubegauze Learning Objective: Recognize factors and techniques involved in 10-49. What covering material is subject to masking work to be contact plated. having the plating material deposited Textbook page 14-42. inside the cover? 1. Carbon felt 2. Orlon 10-55. Which of the following materials should 3. Cray Scotchhrite NOT be used for masking in contact 4. Dacron felt plating operations? 1. Common masking tape 10-50. What should you do with a covered 2. Copper tape plating tool that has been slightly 3. Vinyl tape used today and could be used to continue 4. Polyenter tape a atmilar plating operation tomorrow? 1. It must he discarded and a new tool 10-56 A small margin of aluminum tape exposed made up the next day at the edge of the plating area will 2. The cover must be discarded, but provide what beneficial factor? the tool can he cleaned and used 1. It will make a good surface for again another layer of vinyl tap( 3. Clean the tool and recover it today 2. It will confine the pla" to the 4. Squeeze the cove- dry, wrap it in desired area since alum, ,um does plastic, and use it the next day not plate 3. ft will give an early and nartileas indication of burning conditions 4. It will add some alumiIn co Inc plating metal

62

f) 4 j Learning Objective: Plan a Learning Objective. Cite practices typical plating job. Textbook which will develop and improve your pages 14-43 through 14-53. proficiency in contact plating. Textbook pages 14-53 and 14-54.

10-57. In Example #1 in the text, considering the purpose of the deposit and the 10-63. You are familiarizing yourself with a information in Tables 14-8 and 14-9, new solution by using very high and very why was Cobalt 2043 chosen instead low voltages while plating a scrap part. of Nickel 2080 as the plating Why? solution? 1. To see the effect on the controls 1. Greater maximum buildup is possible 2. To see the appearances of bad with cobalt deposits 2. The cobalt solutic.i is c!aper and 3. To test the quality of the solution easier to use 4. To determine the optimum contact area 3. The cobalt solution provides a better color match with steel 10-64 What is the principal reason you should 4. For the reasons given in both 2 ensure your working position is comfort- and 3 above able before starting a plating job? 1. To maintain maximum efficiency and 10-58. If the plating thickness on the bore in concentration for as long as the job Example 01 in the text were 0.002 inches, takes it would reduce the 3.5015 in. bore _o 2. To make the work more enjoyable 1. 3.4963 in. 3. To avoid boredom 2. 3.4975 in. 4. To decrease the overall preparation 3. 3.4985 in. and plating time 4. 3.4995 in.

10-59. If the plating solution were Nickel Learning Objective: Review 2080, what woul(t be the plating amperage procedures for preparing surfaces in step 07? for plating. Textbook pages 14-54 1. 38.5 through 2. 77.0

3. r, 4. 30-65. The operations performed in the preparation of a part for plating 10-60. Wh e formulas on page 14-66 will depend on 7 ankd to etermine the amount of 1. the type of plating solution to be ;-,t1,4r, s ution required? used 2. the available preparation solutions 1. Fnc .1: 4 3. the fequi,ements for producing a 9. FcrwJL 5 perfectly clean surface on the base metal 'ot t 7 4. the ultimate use of the plated part

, cotton tubegauze selected as 10-66. What factor must be considered in Anal cover in Example #1? performing a cleaning and deoxidizing 1. Greater durability operation on ultra-high strength steel? 2. less exrensive 1. The hardness of the oxides that 3. ngh aboorbancy form on these steels 4. Easier to wrap 2. Avoiding hydrogen embrittl_mstnt of surfaces being cleaned 10-62. In Example 02, what la the pho,..f 3. These steels can be cleaned only by using the Nickel 2085 solutes' abrasion 1. Faster buildup 4. Deoxidizing of thecae steels is not 2. Easier to machin' necessary 3. Color match wit tl ,sae metal #. Lower cost that, C,Ipper 2050 10-67. What ip toe indication ofa successful clean!rc; coo deoxidizing operation? 1. 4 uniform, dull, grainy appearance Learning Objective:Test plating 2. A light carbon film on the surface deposits. Textbook pages 14-63 3. Water flows off the surface without through 14-67. Forming droplets 4. 71a tool surface remains cool 10-71. In using the chisel, knife,or saw 10-68. VII: are the results of etching? test, you should cut in what direction? 1. Straight down into the plating 1. A uniiorm, dull, grainy appeaceice 2. Across the plating 2. At least 0.006 in. of material has 3. From the base metal to the plating been removed 4. From the plating to the base metal Water "breaks" on the surface 4. All of the above 10-72. Which of the following problems will cause separation between preplate and 10-69. 1.: 4diately before plating, stainless plate layers? st.ols must undergo what treatment? 1. The surface was not properly etched 1. Desmutting 2. The base is an improperly sprayed 1. Etching deposit Drying 3. The base metal was not identified Activating correctly 4. An incorrect plating solutionwas 10- ,n Yov. are prepte,ng stainless steel for used plp.-ing wit.. Copper 2055. Immediately acttywag the part you should 10-73. When a deposit is nct as thickas it 1. 4.,711 should be, underestimating thearea to reklte, it be plated or underestimating the amp-hr or: _1 factor are possible causes. 4. der : 10-74. Properly deposited metals can be successfully machined with which of the following devices? 1. Carbide and tool steel cutting tools 2. Dry grinding and high cutting speeds 3. Carbide tools and grinding wheels 4. Heavy cuts and soft wheels

f;

64 Assignment 11 The Repair Department and Repair Work

Textbook assignment: Pages 15-1 through 15-45

11-8. In the repair department of A repair ship, which officer(s), in addition to Learning Objective: Describe the the assistant repair officer, may be organization of a typical tender's assigned to help the repair officer repair department. Textbook pages carry out his functions? 15-1 through 15-8. 1. Production engineering assistant 2. Radiological control officer 3. Department training officer 11-1. Which type of repair ship provides 4. Any or all of the above general and specific repairs to all types of ships? 11-9. In a ship's repair department, who may 1. AR be assigned as the R-2 division officer? 2. ARG 1. Commissioned officer 3. AS 2. Warrant officer 4. AD 3. Chief petty officer 4. Any one of the above

In items 11-2 through 11-5, match the designa- 11-10. Shop layout and arrangement may vary tion of the division in column A with the from one repair'ship to another. associated repair department shop in column B.

A. Division B. Shop Learning Objective: Identify principal dimensions of a spur gear. 11-2. R-1 IC Repair Textbook pages 15-9 through 15-13.

11-3. R-2 Machine 11-11. The distance from one side of the root 11-4. R-3 Calibration circle to the opposite side passing through the center of the gear is 11-5. R-4 Shipfitter called the 1. whole depth 2. root diameter 11-6. The repair officer aboard a destroyer 3. circular pitch tender performs all EXCEPT which of the 4. working depth following functions? 1. Issuing and enforcing repair 11-12. What is the abbreviation symbol for department orders chordal thickness? 2. Scheduling and assigning ships for 1. CT availabilities 2. c t 3. Accepting or rejecting work requests 3. t 4. Initiating requests for additional 4. 'ft funds 11-13. In spur gear terminology, what is the 11-7. Aboard a typical repair ship, who is dedendum (DED)? responsible for the detailed training 1. The circle formed by the top of of repair department personnel? gear teeth 1. Senior division PO 2. The whole depth minus the clearance 2. Assistant repair officer 3. The circle formed by the bottoms 3. Repair officer of the gear teeth 4. Educational services officer 4. The depth of the tooth inside the pitch circle

65 11-14. Backlash (B) is the difference between 11-15. the tooth thickness and What is the most importantcalculation the tooth space of a spur gear? of engaged gear teeth at thepitch circle. 1. Pitch circle 2. Outside diameter 3. Diametral pitch 4. Chordal thickness

In answering items 11-16through 11-19, refer to figure 11Awhich follows.

Figure 11A 11-16. The pitch diameter is represented by 11-19. line If B is 4 inches and D is 5/8inch, 1. A what is the root diameter? 1. 2. 8 23/4in. 2. 3 3. C in. 3. 4. D 31/4in. A. 31/2in. 11-1/. The circular pitch of a gear Is 11-20. indicated by Computation involving geardimensions 1. E is simpler if measurementsare based oil 2. H the diameter of the pitchcircle 3. J instead of the circumferenceof the 4. K pitch circle.

Items 11-21 through 11-26, 11-18. The whole depth ofa gear tooth is refer to equal to a 32-tooth gear whose outsidediameter is 4.25 inches. 1. E + G 2. E + F 11-21. 3. B - A What is the whole depth oftooth of 4. E + F + G this gear? 1. 0.2696 in. 2. 0.4044 in. 3. 0.4348 in. 4. 0,5285 in.

66 11-22. What number cutter shot. i )e used to 11-29. What device is used to measure a shaft cut this gear? runout? 1. No. 3 1. Dial indicator 2. No. 4 2. Micrometer 3. No. 7 3. Vernier caliper 4. No. 8 4. Steel rule

11-23. To check the accuracy of gear tooth 11-30. In bending a shaft to eliminate a thicknesses, what should you use? runout 0.3 inch, you should release ram 1. A micrometer pressure when the dial indicator 2. A vernier caliper indicates a reverse bend of 3. An indexing device 1. 0.003 in. 4. Formulas based on the diametral 2. 0.03 in. pitch system 3. 0.30 in. 4. 0.303 in. 11-24. What Ls the chordal c4dendum of a tooth on this gear? 11-31. You are co stub a damaged shaft 2 inches 1. 0.0386 in. in diameter. After you cut off the 2. 0.1274 in. damaged part, you should drill a hole 3. 0.1964 in. at the end of the undamaged shaft of 4. 0.2696 in. what diameter? 1. 5/8in. 11-25. The chordal tooth thickness of a tooth 2. 11/4in. on this gear is equal to 4 times the 3. 2 in. sine of 4. 21/4in. 1. 1°51' 2. 2°49' 11-32. The stub you make for a shaft 2 inches 3. 3°45' in diameter should have a diameter of 4. 4° 1. 3/8in. 2. 1 1/4in. 11-26. What in the diameter of the stock you 3. 2 in. should use for making a gear of this 4. 2 1/4in. size? 1. 4 1/8 in. 11-33. When stubbing a damaged shaft, you 2. 4 1/4 in. should chamfer the shoulder of the 3. 4 3/8 in. machined end of the stub as much as 4. 4 1/2 in. the end of the undamaged part of the shaft has been chamfered.

Learning Objective: Perform typical shop calculations relating Learning Objective: Identify key to fabricating parts. Textbook points of common valve repair pages 15-14 through 15-16. operations. Textbook pages 15-16 through 15-28.

11-27. To make a tapered shaft 20 inches long whose maximum diameter is 2 1/2 inches 11-34. The bodies of high-temperature, high- and minimum diameter is 2 inches, what pressure valves are usually made of size of round stock should you use? 1. Monel 1. Length 19 15/16 in., diameter 2. alloy steel. 2 3/8 in. 3. Stellite 2. Length 19 7/8 in., diameter 2 5/8 4. bronze in. 3. Length 20 1/16 in., diameter 11-35. Which valve seat material has the 2 5/8 in. greatest maltwater corrosion resistance? 4. Length 20 1/8 in., diameter 1. Alloy steel 29/16 in. 2. Monel 3. Bronze 11 -2R. When machining steps 11 and 12 nr 4. Brass noted in figure 15-10 of the textbook are performed, the groove should he cut last.

67 11-36. In which situation willa globe valve 11-43. Most ball valves are of the likely be removed from theline for quick-acting repair of the valve seat? type, requiring only a 900turn to completely open or close the 1. When the valve seat issurfaced valve. with Stellite 11-44. 2. Gate valves are not suitablefor When the valve seat has beendeeply cut throttling purposes because theflow is difficult to control. 3. When the valve seat hasbeen threaded into the valve line 11-45. 4. To lap slight defectsin gate valve When the size of the valveis seat rings, you shoulduse the wedge between 1/4 in. and 12in. gate coated with a medium gradelapping 11-37. compound. Which operation includescoating a valve seat with prussian blue? 11-46. 1. Grinding '.'ow are gate valves classified? 2. Spotting-in 1. Rising stem valves 2. 3. Lapping Nonrising stem valves 4. Facing 3. Both 1 and 2 above 4. Quick-acting stem valves 11-38. In what valve-seatingoperation is 11-47. To repair gate valves for abrasive placed between thedisk and defects such seat of a globe valve? as light pitting or scoring, whatis 1. Grinding the correct procedure? 1. 2. Lapping Machine the gate on a lathe 2. 3. Refacing Replace the gate 4. Machining 3. Lap the gate 4. Grind the gate 11-39. On a globe valve seat, how should small 11-48. pits he removed? In repairing a Leslieconstant-pressure 1. By lapping governor for a main feedpump, you 2. By grinding should keep lapping of thedamaged 3. By refacing areas to a minimum. 4. By spotting-in 11-49. The letter A stampedon a valve holt or 11-40. nut indicates a special-purpose Which practice is likelyto produce a poor loppin3 job on a vi.ve? characteristic of its 1. 1. Rotating the working thread design position of 2. the tap on the seat thread gage 3. metal 7. lire ink; light pressure on the lap 4. surface 3. Using side pressureon the lap 4. Frequently renewing the lapping 11-50. compound Before tightening bonnetnuts on a high-pressure steam valve,you should 11-41. first hack the disk Which of the followingmaterials is away from the seat. hest suited for manufacturing a lapping 11-51. tool? What instrument is usedto determine 1. Monel the nut tension ina high-pressure 2. Alloy steel steam valve assembly? 1, 3. Brass Micrometer 2. 4. Cast Iron Ratchet wrench 1. Spring sccle 11-42. Compressible washer On a globe valve, what repairopera- tions require the use of an abrasive 11-52. compound? To tpNI overhluled steam valvesin the shop, y.0 should apply 1. Grinding and refacing 1. 2. Grinding and lapping high-pressure steam 2. 3, Lapping and spotting -In high-pressure water 3. 4. Spotting-in and grinding compressed air 4. prussian blue solution

68 1),. ;, 11-59. In the tropics especially, rust preven- Learning Objective: Identify key tion should be a part of the lubricating points applicable to repairing and cleanup routine. How often should pumps. Textbook pages 15-29 the bare metal surfaces of machines be through 15-31. gone over with a rust-preventive com- pound? 1. Daily 11-53. Which of the following parts of a 2. Weekly centrifugal pump generally has a renew- 3. Biweekly able surface? 4. Monthly 1. Impeller passage 2. Balance passage 11-60. In securing a machine shop for sea, 3. Rotor shaft which of the following procedures should 4. Discharge chamber you follow? 1. Pack small gear in locked drawers 11-54. Pre I-0 shaft sleeves are removed and cabinets

fro t p, with the aid of a 2. Lower, block, and secure all top-

1. r ; filler heavy machinery 2. slccve puller 3. Secure suspended equipment such as 3. lathe chain falls, trolleys, and overhead 4. torch cranes 4. Do all of the above 11-55. What tool is used to remove worn impeller wearing rings from a centri- fugal pump? Learning Objective: Describe how 1. Hydraulic press to remove broken bolts and studs. 2. Lathe Textbook pages 15-32 through 15-36. 3. Drill press 4. flex key 11-61. In the removal of broken studs with a 11-56. When replacement wearing rings for a screw extractor, what is the first step? centrifugal pump have inaccurate con- 1. Center punch the center of the bolt centricity, how can you usually 2. File the broken portion of the bolt correct the diameters? 3. Drill the hole to accept the screw 1. By grinding extractor 2. By lapping 4. Hit the bolt with a hammer to 3. By machining loosen the thread 4. By polishing with emery paper 11-62. When drilling a hole in a stud that 11-57. When chucking a casing ring in a 4-jaw has been broken below the surface of chuck, you should exercise caution to the piece it was holding, why;. shoul4 prevent you use to center the drill? 1. cutting the ring 1. Drill index 2. distorting the ring 2. Tap drill 3. enla ring the ring 3. Drill guide 4. shrinking the ring 4. Drill extractor

Learning Objective: Cite principal considerations in maintaining machine shop equipment. Textbook pagen 15-31 and 15-32.

11-58. As desigq,1 in the'-M system, imple- menting RyHtemntic planned maintenance

should improve the 1 vel of operational resdinean of maintainable imp:in:neat and preserve thin level of readin q at all timen.

69 11-64. In manufacturing a pistonring, what should you use for finish Learning Objective: Describe machining? how to make a piston ring. 1. A 4-jaw chuck 2. A mandrel Textbook pages 15-36 through15-45. 3. A faceplate 4. A grinder 11-63. In manufacturing a pistonring, how should you machine the insidebore of the billet? 1. Mat.,ine 0.010 inch oversize 2. Machine 0.010 inch undersize 3. Machine to finished size 4. Rough machine

4 U.S. GOVERNMENT PRINTINGOFFICEt 1981-740-086030 COURSE DISENROLLMENT

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NAVAL EDUCATION AND TRAINING PROGRAMDIVELOPMEN i.:ENTER WILDING 2435 (PD 4) PENSACOLA, FLORIDA32509 PR1NT OR TYPE NRCC Machinery Repairman 362 NAVEDTRA 10530-E

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