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Home , Abrasive, Coated abrasive, Grater, Jointing (sharpening)

Sam Brown

Editor Getting the Most Out of Your

13th ed 1939

Forty pages packed with details about using the belt , the disk sander, the grinder, the buffing head, with many other details -- over 220 photographs and line-drawings -- organized in 12 chapters and an appendix. Grinding twist , using cuttoff-wheels, and just tools makes this manual almost as useful today as in 1939.

I admit that I'm puzzled about the “13th edition”. My inclination is to think of “13th edition” as 13th printing. By edition, publishers usually mean “editorial changes and revisions”. Instead, I think Delta simply means that this is the 13th “printing”. Regardless, whether as the 13th edition or 13th reprinting, this number is indicative of how popular this manual on abrasive tools turned out to be.

Finally, please forgive me for the lack of uniformity in the document's pages. Very thoughtfully, a website reader pointed out the document's discrepancy: it had several missing pages. Since I was occupied with another area of history at the time, I simply did a “quick-and-dirty” fix; that is, I scanned in the missing pages, but did not worry about variations in coloriation. BookBook No. 45314531 250

fr OUTINGCE1TINC THETHE MOSTMOST OUTOUT OFOF YOURYOUR ABRASIVE TOOLS

• THE • THE DISK SANDER • THE GRINDER ELT • THE BUFFING HEAD MIL A EE

Published byby DELTIVDELTA/

GETTINGGETTING THE MOST OUTOUT OF YOUR ABRASIVE TOOLSTOOLS

THIRTEENTH EDITION A DELTA-CRAFT PUBLICATION

Edited by SAM BROWN

A CompleteComplete ManualManual Covering Covering the the Use Use of of Abrasive Abrasive Tools in thethe HomeHome Workshop,Workshop, Illustrated Illustrated with with Over TwoTwo Hundred Hundred Photographs Photographs and and Line Line Drawings. Drawings.

DELTA POWER DIVISION

ROCICM CI IMANUFACTURING COMPANY COMPANY MILWAUKEE 1, WISCONSIN

Printed in U. S. A.

Form AB-9395-9-50 Copyright The Delta Manufacturing Co., 1939

MAIN CONTENTSCONTENTS

GETTING THE MOSTMOST OUTOUT OFOF YOUR ABRASIVE TOOLS CHAPTER ONE-ABRASIVEONE-ABRASIVE TOOLS TOOLS The Grinder—The Buffing Buffing Head—The Head—The Belt Belt Sander—The Sander—The Disk Disk Sander—Sanding Sander—Sanding and and Grinding Attachments—Mounting Attachments—Mounting Sanding Sanding Disks—Fitting Disks—Fitting Abrasive Abrasive Sleeves—Sane Sleeves—Sane ing Belts—MountingBelts—Mounting Grinding Grinding Wheels Wheels 4-6 CHAPTER TWO-ABRASIVESTWO- Natural Abrasives—Artificial Abrasives—Artificial Abrasives—Grain Abrasives—Grain Size—Grinding Size—Grinding Wheels—Coated Wheels—Coated Abra• Abra• sives— Wheel Selection—Special Selection—Special Types Types of ofAbrasivesAbrasives 7-8 CHAPTER THREE-OPERATING THREE-OPERATING THE THE BELT BELT SANDER SANDER Surfacing—End Work—Sanding Work—Sanding Inside Inside Curves—Short Curves—Short Work—Use Work—Use of Sanding of Sanding Table— Table— Inside Corners—CircleCorners—Circle Jigs—Tilting Jigs—Tilting —Pivoted Fence—Pivoted Arm—Beveling Arm—Beveling —Use Jig—Use of Formsof Forms 9-12 CHAPTER FOUR-OPERATING FOUR-OPERATING THE THE DISK DISK SANDER SANDER Freehand Sanding—PivotSanding—Pivot Jigs—Rounding Jigs—Rounding Corners—Pointing Corners—Pointing —Use Dowels—Use of Miter of Miter Gage—Grinding —Large Metal—Large Work—Sanding Work—Sanding with with Pattern—Sanding Pattern—Sanding to Width—Use to Width—Use of Double Disk—SandingDisk—Sanding Long Long Edges—Selection Edges—Selection of of Abrasive Abrasive 13-1513-15 CHAPTER FIVE-GENERALFIVE-GENERAL GRINDING GRINDING Safety Suggestions—Odd Jobs—Position Jobs—Position of of Tool Tool Rest—Use Rest—Use of ofGuides Guides 1616 CHAPTER SIX-HOW SIX-HOW TO TO SHARPEN SHARPEN TOOLS TOOLS General— —— Chisels—Honing—Plane Irons—Wood Irons—Wood Turning Tools—The Tools—The Skew Skew Chisel —The Parting Tool—The Tool—The Gouge— Gouge—Lathe To& To& Bits—Circular Bits—Circular —Mortising Saws—Mortising Chisels Chisels —Grinding Jointer —Setting Knives—Setting Jointer Jointer Knives—Grinding Knives—Grinding Knives Knives in Head in Head 17-22 CHAPTER SEVEN-GRINDING SEVEN-GRINDING SHAPER CUTTERS CUTTERS Rake Angle—Amount of of —Projected Bevel—Projected Shape—Making Shape—Making a —Use a Knife—Use of Shaped of Shaped Wheels—Honing Knives Knives 23-24 CHAPTER EIGHT-GRINDINGEIGHT-GRINDING TWIST TWIST DRILLS DRILLS Point Angle—LipAngle—Lip Clearance— Clearance—Drill Grinding—Web Grinding—Web Thinning—Drill Thinning—Drill for Brass—Specialfor Brass—Special Grinding—Wheels forfor Drill Drill Grinding Grinding 25-27 CHAPTER NINE-BUFFINGNINE-BUFFING AND AND POLISHING Polishing—Polishing Wheels—Setting Wheels—Setting Up—Concerning Up—Concerning Glue—How Glue—How to to Polish—Buffing Polish—Buffing —Strapping Belts—Buffing Belts—Buffing Compounds Compounds 28-30 CHAPTER TEN-HOW TEN-HOW TO TO USE USE SANDING SANDING DRUMS DRUMS Sanding Drums—Sanding on on Lathe—Narrow-Face Lathe—Narrow-Face Drums—Sanding Drums—Sanding on on Drill Drill Press- Press— Pattern Sanding Sanding 31-32 CHAPTER ELEVEN-HOW ELEVEN-HOW TO TO USE USE CUT-OFF CUT-OFF WHEELS WHEELS General Use— Tubing—Cutting Tubing—Cutting Solid Solid Stock—Cutting-off Stock—Cutting-off on Grinder—Diamondon Grinder— —Cutting-off on on Lathe Lathe 33-34 CHAPTER TWELVE-MISCELLANEOUSTWELVE-MISCELLANEOUS ABRADING ABRADING OPERATIONS OPERATIONS Tumbling—Spun Finish—Grinding Finish—Grinding —Engine Glass—Engine Finish Finish — —Internal Internal Grinding Grinding — Other — Other Lathe Operations—GrindingOperations—Grinding Keyways—Surface Keyways——Grinding Grinding—Grinding on Shaper—- on Shaper—Sand- ing on Band on —Sanding Band on Lathe Saw—Sanding on Lathe 35-38 APPENDIX Abrasives andand Abrasive Abrasive Terms—Coated Terms— Abrasive Selection—Comparative Selection—Comparative Grain Grain Sizes Sizes —Grinding Wheel Wheel Selection—Wheel Selection—Wheel Speeds—Belt Speeds—Belt and and Drum Drum Speeds—Grinding Speeds—Grinding Wheel Wheel Speeds in R. P. M. 39-40

OTHER BOOKSBOOKS IN THIS SERIES: Each .250.250 PostpaidPostpaid • GETTING THE THE MOST MOST OUT OUT OF OF YOUR YOUR LATHE LATHE • GETTING THE THE MOST MOST OUT OUT OF OF YOUR YOUR SHAPER SHAPER • GETTING THE THE MOST MOST OUT OUT OF OF YOUR YOUR DRILL DRILL PRESS PRESS • GETTING THE THE MOST MOST OUT OUT OF OF YOUR YOUR CIRCULAR SAW AND AND JOINTER JOINTER • GETTING THE THE MOST MOST OUT OUT OF OF YOUR YOUR BAND BAND SAW SAW AND AND SCROLL SAW

[2] • ABRASIVEABRASIVE TOOLSTOOLS playplay anan importantimportant rolerole inin industryindustry andand inin thethe homeshop. Machines specifically designeddesigned forfor abradingabrading includeinclude the grinder, the belt sander, the disk sander and the buffing head,head, but practically every other tool in thethe shopshop cancan bebe setset upup forfor abrasive work. Typical operations which are done onon oneone oror moremore ofof these machines include sharpening tools, sanding wood and metal,metal, polishing and , gumming circular saws, holes in glass, cutting metals and so on through a long list ofof everydayeveryday shop operations. AA workingworking knowledgeknowledge ofof abrasives and abrasive methods is essential for thethe successfulsuccessful practicepractice ofof suchsuch work,work, andand it it is is the aim of this book to supply this information in aa simple,simple, non-tech-non-tech- nical style readily applied toto averageaverage equipmentequipment inin thethe smallsmall shop.shop. ABRASIVE TOOLS PULLEY GUARD 4111ftimig, TRACKING These photos show three typical abrasive tools—The ADJUSTMENT , the Belt Sander, and the DiskDisk Sander.Sander. The grinder is a light-duty model and is belt-driven. The belt sander is a medium-size unit using six inch wide abrasive belts. The disk sander is direct-motor ABRASIVE drive and uses twelve inch diameter abrasive disks. BELT BELT All units are commonly described according to the TENSIONER abrasive area—aarea—a six inchinch grinder (wheel diameter), a six inchinch belt sander (belt width),width), aa twelve inch inch disk TILTING sander (disk diameter). TABLE _TILT_T ILT SCALE

W1-4WHEEL EEL PULLEY •GUARD7:/ARD _ & BELT DUST GUARD DEFLECTOR

LIGHT-DUTY BELT BENCH SANDER GRINDER

G U ND 1/2 H,P, 1•1 MOTOR ABRASIVE DISK CEMENTED TO PLATE

T1TI LTLT IN G TABLE

TILT AOJUSTMEADJUSTME

MOTOR-DRIVE DISK SANDER

\M IT ,MITERER GAGE GAGE

141 CHAPTER ONE ABRASIVE TOOLS

The Grinder.Grinder.—The— The Grinder is is a a double double end end horizontal spindle, spindle, the the ends ends of of the the spindle spindle being threaded and and fitted fitted with with flanges flanges to to take thethe grinding grinding wheels. wheels. The The spindle spindle is is of ten aa continuationcontinuation of of the the motor motor shaft, shaft, in whichwhich casecase thethe unitunit is is direct-driven. direct-driven. Other models models employ employ a aconventional conventional belt belt drive. TheThe size size of of thethe grinder grinder is is commonly commonly taken fromfrom the the diameter diameter of of the the abrasive abrasive wheel used inin connectionconnection with with it, it, that that is, is, a a grinder swinging swinging a a 7-inch 7-inch wheel wheel would would be be called aa 7-inch7-inch grinder. grinder. Units Units are are further further described as as bench bench or or pedestal, pedestal, the the latter latter indicating aa floor floor model. model. An essential featurefeature of of all all grinders is is the the wheel wheel guards. guards. these shouldshould encloseenclose the the wheel wheel as fully asas possiblepossible inin order order to to prevent abrasive abrasive chips chips or or Above, belt-drive bench bench grinder grinder fitted fitted larger fragments fragments of of the wheel with safety safety hoods hoods as as wellwell as as wheel wheel from beingbeing thrownthrown at at the the oper- oper- guards. TheThe buffingbuffing head, head, left, left, is is ator. TheThe tool tool rests rests should should be similar to to a a grinder grinder except except guards guards wheel and tool restsrests areare omitted. omitted. Lower Lower adjustable to to allow allow for for photos show a light-duty buffing buffing head. head. , andand in in precision precision - grind- Like mostmost similarsimilar belt-drive belt-drive units, units, it it ers, areare alsoalso adjustable adjustable for for tilt. tilt. can be driven fromfrom either either bottom bottom or or The power requiredrequired to to operate operate back asas desired.desired. a 6 or 7-inch7-inch grindergrinder is is approx- approx- imately 1/31/3 h.h. p.p. WhereWhere the the unit unit is is direct- direct- driven, thethe motor motor must must be be a a3400 3400 r. p.p. in.tn. type inin orderorder to to give give the the grinding grinding wheel wheel an efficientefficient rimrim speed. speed. 5500 5500 surface surface feet feet per minuteminute is is a a fair fair standard standard for for average average grinding, although although much much higher higher speeds speeds are sometimessometimes used used for for special special work. work.

The Buffing Head.Head.—The— The buffing headhead is is mechanically similarsimilar to to the the grinder grinder except except that guardsguards and and rests rests are are not not required. required. A A surface speedspeed of of about about 6500 6500 f. f. p. p. m. m. is is suitable forfor average average work. work.

The Belt Sander.Sander.—The— The belt sander features features A plate ofof thisthis diameterdiameter should should be be run run at at a continuous abrasive abrasive belt belt which which works works over over about 17251725 r.r. p. p. m. m. (standard (standard motor motor speed). speed). pulleys at eithereither end end of of a a main main sanding sanding This willwill give a surfacesurface speed speed ranging ranging from from table. AdjustmentsAdjustments are are provided provided for for ten- ten-zero atat thethe center center of of the the disk disk to to about about 5500 5500 sioning andand tracking tracking the the belt. belt. The The size size of of f.p.m. atat thethe rim. rim. Materials Materials likely likely to to clog clog the unitunit is is commonlycommonly designated designated the the same same the abrasiveabrasive should should be be worked worked more more toward toward as the widthwidth of of the the sanding sanding belt belt which which it it the centercenter ofof thethe disk. disk. uses. One-half toto three-quarter three-quarter horsepower horsepower Sanding and Grinding Attachments. — Ac- is required to to operate operate the the belt belt sander. sander. Pul- Pul-cessories forfor sanding sanding or or grinding grinding are are used used leys should bebe suchsuch as as will will give give a a surface surface on the drilldrill press, press, lathe, lathe, scroll scroll saw saw and and other other speed betweenbetween 28002800 andand 3200 3200 feet feet per per machines. TheThe sanding sanding drum, drum, used used on on the the minute. lathe oror drill drill press, press, is is the the best best known known and and The Disk Sander.Sander.—The—The disk sandersander com- com- most used. TheThe surface surface speed speed of of such such drums drums prises aa circularcircular plate plate which which operates operates in ina a is best heldheld toto aa comparatively comparatively low low figure. figure. vertical position.position. Cloth Cloth or or paper backed backed say 12001200 f p. m.m. asas comparedcompared with with an an aver- aver- abrasive disks disks are are cemented cemented or or otherwise otherwise age of about 3000 3000 f.f. p.p. m. m. for for long long belts. belts. A A fastened toto thethe plate. plate. The The diameter diameter of of the the simple testtest forfor efficient efficient speed speed is is indicated indicated abrasive disk disk indicates indicates the the size size of of the the ma- ma- by the abrasiveabrasive drum drum itself, itself, which which will will glaze glaze chine, aa commoncommon size size beingbeing twelve twelve inches. inches. quickly whenwhen operatedoperated at at too too high high a speed.a speed. [51[ 5 1 ABRASIVE SLEEVE

,..„___Ro,,.,c047. RUBBER

DIST IC INTERLOCKINTERLOCK

PATCNPATCF1 1 SPINDLE NUT

CUTAWAY VIEW OF SANDINGSANDING DRUMDRUM STICK .§.1.122

• GRINDING - WNEELWHEEL

BLOTTER BIOMESKIVE FLANGE BELT SPLICES 11 SPINDLE k LEAD /— The proper mounting of the abrasive wheel,wheel, BUSHING disk or belt is important. Disks must be ad-ad- CUP hered flatlyflatly and smoothly in order to do WASHER good work; belt splices must bebe carefullycarefully 0 made in order to secure pliability, pliability, strength, 0 and a non-bump surface.

Mounting Sanding Disks.—In order to pre- This splice is very strong and easy to make, sent a true, flat abrasive surface to thethe but has the disadvantage of a bump at the work, sanding disks are mounted on an joining pointpoint causedcaused byby thethe patch. The accurately-machined metal plate. Glue can plain butt splice, Fig. 5, is made without be used as the , in which casecase thethe special cutting equipment, the cut ends of plate and disk must be clamped between the belt being simply patched together at boards and allowed to dry overnight. Spe- either 45 or 90-degrees. The skived joint.joint. cial types of adhesive are also used, one Fig. 6, is the one most commonly used. If of the most common being "Distic." Distic one end only of the belt is skived, the joint is a stick shellac which meltsmelts underunder heatheat is a single skive;skive; ifif bothboth endsends areare skived.skived and then quickly hardens. To applyapply Distic,Distic, the joint is a double skive. Any suitable a stick is placed flat against thethe angle can be used in making the joint. The bare revolving disk and held firmly inin placeplace grain can be skived from the belt ends by for about half-a-minute in order to heat the using an abrasive stick about threethree sizessizes plate. The stick shellac is then held againstagainst coarser than the belt. Where a suitable abra-abra- the revolving disk, asas inin Fig.Fig. 1,1, andand isis sive brick is not available, the skive cancan bebe moved over the surface until a thin even made by dipping the belt end into hot coat is applied. The abrasive disk is then water, as shown in Fig. 7, after whichwhich the pressed into position, as shown in Fig. 2. abrasive and glue can be readily removed

Fitting Abrasive Sleeves.Sleeves.—Abrasive—Abrasive sleeves from the cloth backing. The joint isis putput upup are mounted on special drums in which with a light coat of medium thick hot glue alternate layers of rubber and fiber, as and is held in a suitable presspress untiluntil dry.dry. shown in Fig. 3, can be expandedexpanded byby turn-turn- as in Fig. 9. ing the spindle nut, thus securing the sleeve Mounting Grinding Wheels.Wheels.—Good— Good quality in place. grinding wheels are metal bushed andand Sanding Belts.Belts.—Sanding— Sanding belts can be pur- should be a snug fit on the spindle.spindle. DisksDisks chased readymade for most belt . of blotting paper should be used on either The worker can also make his own belts side of the wheel to serve as shockshock absorb-absorb- by splicing the to form a ers. The washer which holds the wheel in belt of the proper length. Several varietiesvarieties place should be of the cup type—never a of belt splices are in common use. The flat washer. The spindle nut should bebe interlocking splice, Fig. 4, is made with anan turned up securely, and the thread of the inexpensive cutter.cutter. AA clothcloth patchpatch isis neces-neces- spindle must be such that the nut locks sary to retain the two ends in position.position. against the direction of rotation. [[ 6 ]]

CHAPTER TWO

ABRASIVES

Natural Abrasives.—Natural abrasives areare 12•GRAIN SCREENSCREEN found readyready made made in in the the earth earth and and include include , emery, emery, flint, flint, , garnet, etc. etc. Each Each has itsits ownown particularparticular use. use. Flint Flint is isthe the least expensiveexpensive andand is is the the type type of of abrasive abrasive commonly associatedassociated with with "sandpaper." "sandpaper." ♦ I" ®0 Garnet is is much much harder harder and and tougher tougher than than 000000DOOCIO OBLONG POLYHEDRAL flint andand isis thethe abrasive abrasive most most used used by by the the e'ec2;1519,TWELVE GRA/MS SHAPE SHAPESHAPE woodworker. Emery Emery is is commonly commonly used used for for 7 pockes.poaes. Al* Et* it 7 .11,Jad loves% loree0,7, • . sanding metals.metals. For For a acomplete complete list list of of ,,... 111.10,..- 44-40•440-40.44,,P 440P ois or- • noyit.•47,2.•noit.•47,11.a feefoe VI:4.W%%0' • abrasives and and their their characteristics, characteristics, see see the the BOND • . wft.w. • table inin thethe appendix. appendix. (e,"1147CABRASIVE GRAINS SECTION TFIRUTNRU GRINDINGGRINDING WHEELWHEEL Artificial Abrasives.Abrasives.—Artificial—Artificial abrasives STRA GATGRT CUP CUP DISH DISH are aa productproduct of of the the electric electric furnace. furnace. The The WHEELS GRINDING WHEELS two main groupsgroups are are (1) (1) aluminum aluminum oxide oxide ABRASIVE GRAINSGRAINS abrasives, (2) (2) siliconsilicon carbide carbide abrasives. abrasives. GLUE 1C Aluminum oxide oxide is is made made by by fusing fusing , bauxite, pkCY-lL 6 a highly aluminousaluminous , clay, in in an an electric electric arc arc COATING OF OF POLYHEDRAL POLYHEDRAL GRAIN GRANC D furnace at at about about 3,000 3,000 degrees degrees F. F. The The crystals areare usually usually brown brown in in color, color, but but .091 ν ZI4 1 k/111.0 DISKS AND SHEETS some types areare made made gray gray and and white. white. They They COATING OF OF OBLONG OBLONG GRAINS GRAINS are notnot as as hard hard as as silicon carbide but but are are much tougher.tougher. Silicon Silicon carbide carbide is is made made by by DRUMS ,SPLICE fusing sandsand andand coke coke at at a ahigh high temperature. temperature. ELECTROELECT RO COATING COATING The resultingresulting crystals crystals are are next next in in hardness hardness to the diamond,diamond, but but are are brittle brittle as asopposed opposed to the toughnesstoughness of of aluminum aluminum oxide. oxide. The The II color rangesranges from from black-gray black-gray to to blue-green. blue-green. COATED ABRASIVES BELTS Both aluminumaluminum oxide oxide and and silicon silicon carbide carbide Abrasive grains grains are are graded graded by by passing passing through through screens screens are soldsold underunder various various trade trade names names such such as as and areare thenthen made made into into various various abrasive abrasive products. products. Aloxite, Alundum and and Lionite Lionite (aluminum (aluminum oxide), and Carborundum,Carborundum, Crystolon Crystolon and and shapes, aa fewfew ofof thethe most most common common styles styles Carsilon (silicon(silicon carbide). carbide). being the straight,straight, cup cup and and dish dish wheels wheels shown inin Fig.Fig. 5.5. Grain Size.Size.—The—The grain sizesize oror grit grit is is de- de- Coated Abrasives. —— Abrasive grainsgrains termined by by passing passing the the crushed crushed ore ore over over glued toto sheetssheets ofof clothcloth or or paper paper are are known known various wirewire and and silk silk screens. screens. Fig. Fig. 1 1shows shows as coated abrasives.abrasives. Disks Disks and and sheets, sheets, a 12-grain screen. screen. Grains Grains passed passed by by this this drums, and and belts belts are are common common examples examples of of screen areare called called No. No. 12, 12, twelve twelve grains grains coated abrasives.abrasives. The The polyhedral polyhedral grain grain measuring about about 1 1 inch inch if if laid laid end end to to end. end. shape isis alwaysalways usedused when when coated coated abra- abra- Scientific control methods methods eliminate eliminate flat flat and and slivery grains, Fig. 2, unless desired for sives are mademade by by ordinary ordinary methods, methods, pro- pro- slivery grains, Fig. 2, unless desired for ducing a surface similar to that shown in some specific purpose, retaining only the ducing a surface similar to that shown in some specific purpose, retaining only the Fig. 6. It cancan bebe seen seen that that any any method method of of ideal polyhedral-shapedpolyhedral-shaped grain grain shown shown in in gravity coating with oblong grains would Fig. 3. Sizes range fromfrom No. No. 6 6 to to No. No. 240. 240. gravity coating with oblong grains would result inin an an unsatisfactory unsatisfactory surface, surface, many many of of Since it isis difficultdifficult to to make make a ascreen screen of of the grainsgrains being being almost almost completely completely em- em- more thanthan 240 240 meshes meshes to to the the inch, inch, finer finer grains upup to to No. No. 600 600 are are graded graded by by an an bedded inin thethe glue glue coating, coating, as as shown shown in in Fig. 7. If thethe oblongoblong grains grains are are placed placed on on elaborate water water flotation flotation system. system. end, asas in Fig. 8, the resultresult is is quite quite differ- differ- Grinding Wheels.Wheels.—Abrasive— Abrasive grains fusedfused erent, thethe abrasive abrasive particles particles being being fully fully ex- ex- with aa bondbond of of flux flux and and clay clay or or other other sub- sub- posed and capablecapable of of clean, clean, uniform, uniform, high high stance cancan be be cast cast into into any any convenient convenient speed sanding.sanding. This This vertical vertical coating coating of of shape, suchsuch as as the the familiar familiar grinding grinding wheel. wheel. abrasive grainsgrains is is done done by by an an electrostatic electrostatic Each graingrain thus thus becomes becomes a aminiature miniature cut- cut- method, andand the the greater greater portion portion of ofall all ting tool,tool, asas shownshown in in Fig. Fig. 4. 4. As As the the coated abrasivesabrasives used used today today are are made made in in grains wearwear down down and and become become dull, dull, they they this manner.manner. are torntorn loose loose from from the the bond, bond, exposing exposing a a Coated abrasivesabrasives are are divided divided into into many many new, sharp set set of of cutting cutting edges. edges. Grinding Grinding different classes, classes, depending depending upon upon the the abra- abra- wheels are mademade in in hundreds hundreds of of different different sive used, thethe kindkind of of backing, backing, whether whether for for [[7] 7 ] CLASSIFICATION OF GRINDING WHEELS

GRAIN SIZES: Number of Abrasive Grains to the Inch. VERY COARSE COARSE MEDIUM FINE VERY FINE FLOUR SIZES 8 12 30 70 150 280 10 14 36 80 180 320 16 46 90 220 400 20 60 100 240 500 24 120 600

GRADE: Strength of Bond. VERY SOFT SOFT MEDIUM I HARD VERY HARD Carborundum W, V, U T, S, R, P, 0, N M, L, K, J, I H, G, F E, D Norton E, F, G H, I, J, K L, M, N, 0 P, Q, R, S T, U, W, Z

wet or dry sanding, etc. In any of these, coarse grain gives best results; for hard, the normal coating is put on in a close, brittle materials, the abrasive grains should packed formation, hence the general de- be fine. The general run of work is done scriptive term "closed coat." The closed with 60-grit wheels. coat is fast-cutting and durable, but has the The grade of a grinding wheel describes disadvantage of clogging under certain the bond as being hard, medium or soft. conditions. Where the coating is spaced Grains are easily loosened from a soft to show a slight separation between the wheel, making it practically self-dressing, abrasive grains, the coating is described as while the hard wheel holds together under "open coat." Open coated abrasives are extreme pressure. Hard wheels are gen- not as durable as close coated, but they erally used for grinding soft materials, are useful for finishing certain materials while soft wheels are used for grinding where the abrasive dust tends to clog the hard materials. For all average work, a disk or belt. medium hard grade will wear well while retaining a sharp edge. In a somewhat similar manner, the grains The selection of the proper structure is in a grinding wheel are spaced, the word determined by the nature of the material "structure" being generally used to indicate to be ground. Generally, soft materials, this abrasive spacing. For all average which tend to clog any abrasive wheel, usage, grinding wheels are supplied in a require a wheel with abrasive grains widely medium structure. spaced. Opposite to this, hard, brittle Grinding Wheel Selection.—Most grinders materials require a wheel with closely- are supplied with a general-purpose grind- spaced abrasive grains. The wide spacing ing wheel and this wheel will handle most gives a coarse finish; the close spacing, fine. of the work encountered in the home or Vitrified wheels are the common selec- small production shop. Where, for any tion as to bond. Cut-off wheels subject to reason, a special wheel is required, the user deflection strains are generally bonded with can arrive at a workable selection by fol- , shellac or rubber. lowing a few simple rules. Every grinding wheel has five distinguishing features: (1) Special Types of Abrasives.—Both alu- Abrasive (aluminum oxide, silicon carbide, minum oxide and silicon carbide abrasives etc.), (2) Grain (size of abrasive grains), are made to special formula other than standard. The pure white aluminum oxide (3) Grade (strength of bond), (4) Structure (grain spacing), (5) Bond (what kind of wheel is not as tough as regular aluminum oxide, and hence fractures under mild pres- material used). sure. This feature prevents overheating, The abrasive should be considered first. making white aluminum oxide suitable for Only the aluminum oxide and silicon car- grinding high speed steel. The principal bide abrasives need be considered. Aluminum variation from regular silicon carbide is the oxide is used for grinding all materials of green crystal, which features a low order of high tensile strength, such as steels, toughness but is extremely hard and brittle. high speed steel, malleable iron, wrought This feature makes green silicon carbide iron, etc. Silicon carbide is used for grind- ideal for cutting and grinding glass and ing materials of low tensile strength, such extremely hard alloys. The hardest of all as gray iron, brass and soft bronze, alu- abrasive grains is the diamond, and this minum, copper, etc. Either type of abrasive type of grinding wheel, made from genuine will, generally speaking, give workable re- diamond chips, is extensively used for cut- sults in either class. ting and grinding glass, and for cutting The grain selection is comparatively shapes from blocks of silicon carbide and simple. For soft, malleable materials, a aluminum oxide.

[ 8 ] CHAPTER THREE OPERATING THE BELT SANDER

Surfacing.—The sanding table should be in a horizontal position for surfacing. Work zGOIDE can be done freehand, that is, the piece to be surfaced is simply placed on the table. A light but firm pressure should be used to keep the work in the proper position. Ex- cessive pressure against the belt is unneces- sary and should be avoided. If the work is longer than the table, it is started at one end and gradually advanced in much the same manner as surfacing on the jointer. Where long work is to be surfaced, it is advisable to use the sanding fence as a guide, especially if the board is close to 6 inches wide. End Work.—End sanding is best done with the sanding table in a vertical position, but can be done on the horizontal table by using a guide clamped to the fence, as shown in the drawing. The work is pushed down alongside the guide until it contacts the

Above, surfacing long work. Left, use of diagonal feed. sanding surface. The alignment block per- mits rapid attachment of the guide at proper right angle position. Diagonal Feed. — The use of a diagonal feed, as shown in the center drawing, permits the Curves are sanded on the surfacing of work con- outer drum, left. Photos show use of backstop. siderably wider than the 6-inch capacity of the belt. The angle of the fence should be kept as small as possible in order to minimize cross grain sanding. A fine belt should be used. Sanding Inside Curves.—Inside curves can be sanded on the end drum, as shown in the lower drawing. The table can be either vertical, horizontal, or at an angle. The fence is used as a guide, being held by one bracket only so it

1 9 1 secured toto the the forks forks of of the the pivoting pivoting arm arm by by means ofof anchoranchor points. points. A A master master form form should bebe usedused to to locate locate the the work work at at the the proper position. position. The The lower lower drawing drawing shows shows a simple jigjig forfor sanding sanding circles circles when when the the sanding tabletable is is horizontal. horizontal. Holes Holes in in the the fence to taketake thethe bolts bolts are are for for a aslide slide fit fit so that thethe nuts nuts can can be be turned turned to toobtain obtain adjustments for for circles circles of of a adiameter diameter be- be- tween thethe one-inchone-inch spacings spacings on on the the guide guide board. Normally, Normally, circle circle work work is isdone done with with the sandersander in in a a vertical vertical position, position, using using the the sanding tabletable as as a a support. support. The The same same jigs jigs as described for for use use on on the the disk disk sander sander can can be used onon thethe beltbelt sander. sander. Above, using the tilting table. table. Extremely largelarge circles circles Photo atat rightright shows shows how how inside inside corners are are sonded. sonded. can bebe workedworked by by mount- mount- ing the pivot point on any I ing the pivot point on any extends beyondbeyond thethe convenient benchbench or or sanding belt.belt. on the tabletable of of the the drill press.press. Short Work. —— No feed is required on on Jigs for circlescircles andand circu- circu- short workwork up up to to lar segments segments can can be be used used about 1212 inchesinches long, long, to advantoge.advantoge. since the fullfull lengthlength of such workwork isis inin positive contact withwith a level surface. ThisThis permits the the use use of of a a backstop toto simplify simplify sanding operations.operations. The backstopbackstop can can be be used alone oror in in con- con- nection withwith thethe fence, fence, as as shown inin thethe photosphotos at at the bottombottom of of thethe preced- preced- ing page.page. TheThe fencefence itself itself can can also be usedused asas aa stop stop by by swing- swing- ing it atat rightright angles angles across across the the sanding surface.surface. Use of Sanding Table. — Every kind ofof edgeedge oror end end work work can can be done byby usingusing thethe belt belt sand- sand- er inin aa verticalvertical position position in in con- con- nection withwith thethe sanding sanding table. table. With thethe tabletable level level and and with with the workwork guided guided by by the the miter miter gage, ends andand edges edges can can be be sand- sand- ed true andand smooth, smooth, either either , square, mitered, beveledbeveled or or compound compound beveled beveled as required. A A typical typical operation operation show- show- ing useuse ofof thethe mitermiter gage gage with with tilted tilted table table

is shown inin upperupper photo. photo. Other Other work work is is PIN done inin thethe same same manner manner as as described described in in

following chapter on on use use of of the the disk disk sander. sander. HOLES Inside Corners.Corners. —— Inside cornerscorners can can be be sanded afterafter tracking tracking the the belt belt so so that that it runsit runs exactly flushflush withwith the the edge edge of of the the main main sand- sand- ing table. TheThe side side guard guard plate plate must must be be re- re- moved to permitpermit feeding feeding the the work. work. The The work work is advanced toto the the belt belt alongside alongside the the miter miter gage, as shownshown inin thethe center center photo. photo. A A cut cut GUIDEGUIDE, can bebe takentaken on on both both edges edges of of the the corner corner in in one operation, or, or, each each edge edge can can be be worked worked BOLT in turnturn on on the the flat flat surface surface of of the the belt. belt. NUT— Circle Jigs.—AllJigs.—All of the variousvarious styles styles of of FENCEPENCE circle jigsjigs usingusing aa pivot pivot point point can can be be adapted adapted for useuse onon thethe belt belt sander. sander. The The lower lower photo photo shows the useuse ofof aa pivotpivot arm arm for for segment segment work. InIn this this form form of of jig, jig, the the work work s s [[ 10 ]] ARM V°WEKWORK PIVOTPNOTE0 ED ON BOLT STANDARD . FENCE

'

STOP FOR ARM

A tilting fence fence andand pivot armarm areare aids to „OPENING TO EtsSUIT iETN WOCIK WtelT KO accuracy inin productionproduction work.work. SEGivav contacting the . The arm is then tilted down to make the cut, Fig. 5, the oper- ation being completed when the arm comes in contact CHAMFERINGCI4AMFERI NG JIGJIG with the fence stop. The sander affordsaffords one ofof Beveling Jig.Jig. —— One of the the best methodsmethods of of work-work- cleanest and most accurate ing . methods of beveling, especial- Tilting Fence.Fence. —— For ly on short pieces and end some types of sanding grain, is done with the use work, such as beveling, of a simple vee-shaped jig. a tilting fence can be used Fig. 6 shows the general con- to good advantage. Within struction. The two piecespieces certain limits the regular the vee areare sander fence can be tilted by placing wedges fitted together at right angles, and areare sep-sep- under the bracket arms. More extreme arated at the bottom a suitable distancedistance toto bevels can be sanded by using the simple make the required cut. Fig. 7 shows thethe jigjig fence shown in Fig. 1. This consistsconsists ofof aa in use. The work is simplysimply placedplaced inin thethe veevee wood fence of the same size as the regular groove and held there until the sanding fence. The tilting fence is fastened to the belt ceases to cut. If the jig is mounted regular fence by means ofof twotwo metalmetal arms,arms, close to the belt, the width of the bevel which are slotted to permit adjustments be- will be wider than in the case where thethe ing made.made. A thin but rigid strip ofof metalmetal jig isis mountedmounted higher.higher. EvenEven wearwear onon thethe screw-fastened to the underside of the regu- sanding belt is accomplished byby movingmoving thethe lar fence, as can be seen in Fig. 2, supportssupports fence. Overcutting is impossible, and, pro-pro- the tilting fence above the sanding belt.belt. viding the jig is parallel with the sanding One of the metal arms can be fitted with belt surface, the bevel will be perfectly a scale reading in degrees. uniform and straight from one end of the Pivoted Arm.—A pivoted arm, as shown in work to the other. Fig. 4, can be used for various jobs where Use ofof Forms.Forms. — — Sanding in production the end of the work is to be pointed oror work can often be done more quickly withwith cut off on an angle. The arrangement isis the use of forms. These are made from simply a fairly heavy piece of wood, which wood to the proper curvature, thethe formform be- is bolted toto thethe regularregular sander sander fence. fence. A ing screw-fastened to the regular sanding washer between the pivoted arm and the table. It is necessary in most cases to make fence permits the arm to bebe tiltedtilted oror swungswung a sanding belt to fit, although a very shallowshallow to anyany position.position. A block clamped to the form can be used with the regular sanding fence limits the amount of swing while a belt. A common shape is the circular form, second block clamped to the arm furnishesfurnishes (see Fig. 3, p. 12). This form is a portion of a stop for the end of the work. In use, thethe a true circle, hence, the work can be pushed work is placed on the pivoted arm, one end along it since the curve is the same atat allall Forms cancan be be built built up, up, the the work work surface surface being coveredcovered with with , plywood, as as shown shown in in Fig. 2, oror thethe shape shape may may be be cut cut from from a solid piece ofof wood. TheThe preferablepreferable abrasive abrasive belt forfor useuse withwith forms forms is is the the cloth-backed cloth-backed style. A heavy weightweight backingbacking can can be be used used for mostmost work,work, the the exception exception being being very very abrupt curves curves where where a alight light backing backing gives gives better results. results. Forms Forms of of the the type type shown shown in in Fig. 7, always requirerequire a alight, light, flexible flexible belt belt in orderorder to to conform conform to to the the shape. shape. The The manner in in which which forms forms of of this this kind kind work work can bebe seenseen inin Fig.Fig. 6. 6. The The fence fence is is aligned aligned with thethe shapedshaped portion portion of of the the form form so so that that the workwork willwill bebe in in the the proper proper position position when itit isis pressedpressed oLTw000 against thethe fence fence and and Curved forms forms of of almost almost any any shape shape SANDKV, projected into into the the can be fitted to to the the regular regular sand- sand- FORM belt. Under pressure, pressure, ing table.table. ® the beltbelt takestakes on on the the same shapeshape asas the the points. Fig.Fig. 11 showsshows workwork form andand sands the the being sanded over over a a circular circular work toto thethe desired desired form. AA suitablesuitable fence fence is is shape. AA certaincertain nicety nicety made upup andand clamped clamped to to the the in knowingknowing justjust when when regular fence, fence, thus thus provid- provid- WORK to lift thethe workwork from from ing a sideside supportsupport for for the the FENOE /0 the beltbelt mustmust be be ac- ac- work andand insuring insuring square square BELT quired byby practice. practice. edges. The irregularirregular form, form, MINIU With aa light-weightlight-weight Fig. 4, is not aa partpart of of a a 474 backing surfacedsurfaced with with circle, andand workwork sanded sanded 511FORM" a fine-grit abrasive,abrasive, over thisthis typetype of of form form must must be set downdown atat a a certain certain position, placementplacement being being controlled by by means means of of a a stop block.block. HollowHollow forms,forms, Fig. 5, have curvescurves which which do do not conformconform to to the the belt belt shape. TheThe beltbelt in in this this case case is run ratherrather loose loose so so that that it willwill be fashionedfashioned to to the the same shapeshape asas the the form form when thethe workwork presses presses against it.it.

Above, usingusing aa groovedgrooved form form to to sand sand a around round edge. edge. Photo Photo at atleft left shows a slashed beltbelt being being used used to to sand sand abrupt abrupt edge edge curves. curves. sanding ofof practicallypractically any any moulded moulded shape shape is ispossible. possible. Where thethe shape shape of of the the form form is is composed composed of of very very abrupt abrupt curves, slashedslashed belts belts should should be be used. used. This This type type of of belt. belt. as the namename implies, implies, is is not not a asolid solid surface surface but but is isslashed slashed into stripsstrips about about Y 8Y-inch wide.wide. ShortShort sections sections of of the the belt areare leftleft uncut uncut and and these these uncut uncut portions portions serve serve to to hold the numerousnumerous narrow narrow belts belts together. together. Slashed beltsbelts areare ideal ideal for for sanding sanding odd-shaped odd-shaped edges. edges. This typetype ofof workwork is is done done without without a abacking backing plate plate hence either the the sander sander table table must must be be removed removed or theor the work donedone onon the the back back side. side. The The latter latter is ispreferable preferable for occasionaloccasional work work since since it it is is much much easier easier to toremove remove the backback plateplate than than the the table. table. In In use, use, the the belt belt is runis run rather slack slack so so that that the the work, work, when when projected projected into into it, it, as shown inin Fig.Fig. 8,8, willwill causecause the the belt belt to to assume assume the the proper shape. shape. Edges Edges finished finished in in this this manner manner will will show show a very slightslight curvature,curvature, but but for for all all practical practical purposes purposes the effecteffect isis aa right-angleright-angle cut. cut. Production Production runs runs are are best best done withwith thethe use use of of the the sander sander table, table, since since this this pro- pro- vides a rest forfor the the work work while while insuring insuring proper proper contact contact with thethe belt.belt. It It is is necessary, necessary, of of course, course, to to remove remove the the main sandersander table table before before the the tilt tilt table table can can be beused used [[ 12 ]] CHAPTER FOUR FOUR OPERATING THETHE DISK SANDER

Freehand Sanding.Sanding. —— Sanding onon PIVOT the diskdisk sandersander is is usually usually done done POINT"-POINT , freehand, the the work work being being held held flat flat on the tabletable and and projected projected into into the the sanding disk.disk. A A smooth, smooth, light light feed feed should be be practiced. practiced. Avoid Avoid heavy heavy 0 pressure. Best Best results results on on curved curved TIVT ou S1.10E work can canbe obtained be obtainedby going by going over thethe workwork two two or or three three times times with lightlight cuts.cuts. Sanding Sanding is is always always Imen...-iftwo„,,,r1114111111‘.‘111411 done onon thethe "down" "down" side side of of the the disk; workingworking on on the the opposite opposite side side would, ofof course, pushpush the the work work I /- LOCKING 7 k`ac."'"1ARM --- away fromfrom thethe sanding sanding table. table.

Pivot Jigs.—CircularJigs. — Circular work whichwhich is to bebe sandedsanded should should always always be be worked worked with thethe useuse of of aa pivot pivot jig. jig. Top Top and and bottom bottom views of a simple jigjig areare shown shown in in Figs. Figs. 1 1 and 2.2. CleatsCleats on on the the underside underside provide provide a a positive stop againstagainst the the front front and and side side of of the standardstandard table. table. The The sliding sliding strip strip can can be set atat anyany position, position, and and is is locked locked in in place by pushingpushing down down on on the the locking locking lever, lever, the endend ofof whichwhich works works like like a acam. cam. In In use, use, the workwork is is firstfirst band band sawed sawed to to shape, shape, after after which itit isis mountedmounted on on the the pivot pivot point. point. The The sliding stripstrip is is locked locked at at the the required required dis- dis- tance fromfrom the the sanding sanding disk. disk. Pushing Pushing the the table intointo thethe disk disk sets sets the the cut, cut, and and rota- rota- tion finishesfinishes thethe entire entire edge edge to to a aperfect perfect circular shape. shape. The The jig jig can can be be clamped clamped to to the sandersander table table or or simply simply held held with with one one hand whilewhile thethe other other hand hand rotates rotates the the work. work. Any other style style of of pivot pivot jig jig will will work work equally well,well, thethe simplestsimplest set-up set-up being being a a brad driven driven into into a aboard board which which is clampedis clamped to the sandersander table table at at the the required required distance distance from thethe sanding sanding disk. disk. An An overhead overhead pivot pivot point, asas shownshown at at the the right, right, can can be be made made from circularcircular saw saw hold-down hold-down parts. parts. This This type ofof jigjig isis fullyfully adjustableadjustable and and has has the the advantage of of a a visible visible pivot pivot point point which which can can be accurately set set in in the the center center of of the the work. work.

Rounding Corners.Corners.—The— The sanding ofof cor-cor- ners isis alliedallied toto circular circular work work in in that that the the A pivotpivot jig jig is is almost almost a anecessity necessity in in sanding sanding circular circular edge being workedworked is is part part of of a atrue true circle. circle. pieces if accurate workwork is is to to be be done. done.

SANDING DISK

•I PIVOT

LINES

METHOD OF ROUNDING CORNERS O

[13]

A pencil markmark is is then then drawn drawn on on the the table table of the jig,jig, thisthis markmark being being the the same same dis- dis- tance fromfrom the the pivot pivot point point as as the the pivot pivot point isis fromfrom the the sanding sanding disk, disk, as as shown shown in Fig.Fig. 4.4. TheThe workwork is is placed placed against against a a guide fastened to to the the rear rear edge edge of of the the jig, jig, as shown inin Fig.Fig. 5,5, andand is is brought brought down down on the pivotpivot pointpoint in in alignment alignment with with the the pencil mark. Rotating Rotating the the work work rounds rounds the the corner, see see Fig. Fig. 6. 6. Fig. Fig. 7 7 shows shows how how the the jig jig table cancan be be marked marked with with pencil pencil lines lines as as a a guide to placingplacing work work of of any any radius. radius.

Pointing Dowels.Dowels. — — A hole of the samesame diameter as as the the dowel stock stock is is drilled drilled through a scrap piecepiece ofof woodwood whichwhich is is clamped toto the the sanding sanding table table at at the the required required angle, asas shownshown in in Fig. Fig. 1. 1. The The work work is is pushed throughthrough the the hole hole until until it itcontacts contacts the sandingsanding disk, disk, after after which which it itis isrotated rotated to finish thethe point.point.

Use of Miter Gage.Gage.—A— A circular saw saw miter miter gage can bebe usedused to to advantage advantage in in sanding sanding square or or mitered mitered ends. ends. Where Where miters miters are are being sanded, the the preferable preferable position position is isas as shown inin Fig.Fig. 2,2, whichwhich permitspermits better better handl- handl- ing thanthan the the reverse reverse position position shown shown in in Fig Fig Above, pointing dowels dowels on on the the 3. Square endsends are are sanded sanded by by disk sander.sander. Right, Right, how how to to use use projecting the the work work along along the the the miter gage. gage. miter gagegage untiluntil it it contacts contacts Most work ofof thisthis nature nature the disk.disk. SandingSanding to to exact exact length length can bebe donedone freehand,freehand, can bebe donedone byby pre-setting pre-setting the the sweeping thethe cornercorner of of the the stop rodrod at at the the required required distance. distance . work acrossacross the the face face of of The rodrod is is free free to to slide slide in in the the the sandingsanding disk disk two two or or hole in the endend of of thethe gage, gage, as as three timestimes until until the the de- de- shown inin Fig.Fig. 4,4, thethe exact exact length length sired roundround is is obtained. obtained. being set whenwhen thethe rod rod comes comes to to More accurateaccurate results results are are a stop atat the the bottom bottom of of the the hole. hole. possible if the pivotpivot jig jig is is The bevelingbeveling ofof squaresquare posts posts is is used inin thethe mannermanner shown shown easily done byby usingusing the the miter miter in thethe drawingsdrawings at at the the bot- bot- gage with stopstop rodrod in in the the man- man- tom ofof thethe precedingpreceding page. page. ner shownshown inin Fig. Fig. 5. 5. The slidingsliding stripstrip is is first first Grinding Metal. —— Finishing locked inin placeplace atat the the re- re- metals andand plastics plastics on on the the disk disk quired distance distance from from the the sander is practically thethe same as face of the sandingsanding disk. disk. similar operationsoperations on on wood wood with with the exceptionexception thatthat an an aluminum aluminum Square postsposts areare easily easily beveled beveled by by using thethe gage gage and and stop stop rad rad as as oxide abrasiveabrasive disk disk should should be shown below. used instead ofof garnet.garnet. Large Work.Work.—Where— Where the workwork being sandedsanded is is so so large large that that it it cannot bebe easily easily held held on on the the sander table, table, an an auxiliary auxiliary wood wood table ofof suitablesuitable size size should should be be made, thisthis being being clamped clamped or or otherwise fastenedfastened to to the the stand. stand. and sandingsanding table. table.

Sanding with Pattern.Pattern.—In— In pro- duction work,work, sanding sanding with with the the use of a pattern can can be be used used to to advantage advantage and insuresinsures perfect perfect work. work. A A wood wood table, table, to to one side of which isis screw-fastenedscrew-fastened a a thin thin but rigidrigid strip strip of of metal. metal. is is clamped clamped in inplace place over thethe regularregular sanding sanding table, table, as as shown shown in Fig.Fig. 22 onon thethe oppositeopposite page. page. The The guid- guid- ing edgeedge ofof thethe metalmetal strip strip should should be be about about I/I/88 inch inch from from the the surface surface of of the the sanding sanding disk, andand the the pattern pattern should should be be made made Ye Ye inch undersizeundersize to to correspond. correspond. Anchor Anchor points points permit fasteningfastening the the pattern pattern to tothe the work. work. after whichwhich the the work work is is band band sawed sawed about about

[ 1•1•11‘‘ inch outsideoutside the the edge edge of of the the pattern. pattern. The The work isis thenthen sanded sanded smooth, smooth, the the pattern pattern being held inin contactcontact with with the the metal metal guide, guide, as shown inin Fig.Fig. 1,1, asas thethe work work is is pro- pro- jected intointo thethe sanding sanding disk. disk.

Sanding to Width.—CurvedWidth. — Curved surfaces cancan be sanded toto uniform uniform width width by by first first band band sawing andand smoothing smoothing one one side, side, and and then then using aa spacerspacer pin, pin, as as shown shown in in Fig. Fig. 3, 3, to to set the finishfinish cutcut on on the the opposite opposite side. side. While While the photophoto showsshows the the pivot pivot jig jig used used for for this this purpose, itit can can be be seen seen that that any any scrap scrap piece piece of wood with oneone cornercorner rounded rounded can can be be clamped toto thethe sanding sanding table table to to serve serve as as a a guide. Use of Double Disk. — When workingworking small woodenwooden oror plas- plas- tic parts requiring requiring two two grades ofof abrasiveabrasive for for Clean, accurate workwork in in produc- produc- tion runsruns can can be be done done by by sanding sanding finishing, goodgood useuse with thethe use use ofof aa potter,potter, can bebe mademade of of a a SANDING double sandingsanding disk. disk. SECT/ON DISK from thethe "up""up" side side of of the the This isis made byby cut- cut- GUIDE 1,404 disk, will not comecome inin con-con- DE ting outout thethe center center of of vArii tact withwith thethe sanding sanding sur- sur- the coarsercoarser disk, disk, ce- ce- face until itit reachesreaches the the menting aa smaller smaller "down" side. side. The The angle angle disk of finer abrasiveabrasive should bebe veryvery slight slight and and is purposely exaggeratedexaggerated in thethe illustrationsillustrations to to show show the the method method of of working. AA smoothsmooth feed feed is is essential. essential. Any Any length ofof workwork can can be be handled handled in in this this man- man- ner, or,or, short short pieces pieces can can be be run run through through one after another.another.

Selection of Abrasive.Abrasive.—The— The abrasive usedused on the diskdisk sandersander will will depend depend upon upon the the work. AsAs onon allall otherother abrasive abrasive machines, machines, garnet is is used used for for wood wood while while aluminum aluminum oxide and siliconsilicon carbidecarbide disks disks are are used used for for metal. SinceSince thethe disk disk sander sander is is commonly commonly employed forfor edgeedge work. work. the the abrasive abrasive gen- gen- erally cancan bebe somewhat somewhat coarser coarser than than for for surfacing. AA 11/2/2 or or 1/0 1/0 disk disk cuts cuts rapidly rapidly to to a fairly smoothsmooth sur- sur- (SANDING.(SANDING DISK face. Fine cabinetcabinet WORK work, however,however, re-re- _ quires finalfinal sanding sanding Above, usingusing aa spacerspacer pin pin to to with a 2/02/0 oror 3/03/0 diskdisk sand curved workwork to to exact exact width. width. so abrasive scratchesscratches Right, method method used used in in sanding sanding long, straightstraight edges. edges. 015K will not show. FENCE MOUNTIMOUNTED , ../NOLODOVitrIwoLo.DoverN )210l,D.DOWN401.,0•DOWN in thethe openingopening thus thus pro- pro- ATT SlI4I4TSLIGHT ANGLE ANGL II W vided. TheThe workwork is is first first sanded onon the the outer outer portion portion of of the the disk andand then then without without stopping stopping the the machine, isis finishedfinished by by means means of of the finerfiner abrasiveabrasive disk. disk.

Sanding Long Edges.Edges.—— While the disk sandersander is is not not particularly particularly suited forfor sanding sanding long long straight straight edges, good work cancan be be done done by by using thethe set-upset-up shown shown in in Figs. Figs. 4 and 5.5. AA woodwood fencefence toto which which is fastened aa hold-downhold-down block block is is clamped toto thethe sander sander table table at at the the required distance distance from from the the sanding sanding disk. TheThe woodwood fencefence should should be be mounted atat a a slight slight angle angle to to make make sure thatthat the the work, work, which which is is fed fed [ 15 ] CHAPTER FIVE FIVE GENERAL GRINDING

and safestsafest position position for for general general work. work. Work Work ground in in this this position, position, or or any any other other posi- posi- tion whenwhen thethe work work points points to to the the center center of of the wheel,wheel, willwill bebe finishedfinished with with a a square square edge. It cancan bebe seen, seen, Fig. Fig. 5, 5, that that work work pre- pre- sented inin anyany position position other other than than pointing pointing to the wheelwheel center,center, will will be be ground ground more more or or less on a bevel.bevel. FreehandFreehand grinding grinding without without the useuse ofof aa restrest should should always always be be done done on the lowerlower quarterquarter of of the the wheel. wheel. Use of Guides.—GuidesGuides.—Guides clamped toto thethe regular rest rest insure insure accuracy accuracy and and should should be used onon allall precisionprecision work. work. Fig. Fig. 7 7is is an an example. TheThe exactexact bevel bevel and and depth depth of of cut cut is controlled byby means means of of the the simple simple fence fence against whichwhich the the work work is is placed. placed.

FOLD The grinder plays plays an an Im• im• portant part part in in hundreds hundreds of odd jobsjobs aroundaround the the shop. shop. Smoothing welded joints and cuttingcutting sheet sheet metal metal are typical examples. Safety Suggestions.—The grinder is a safe tooltool toto operateoperate providing providing SHEET/ a few simple rulesrules are are followed. followed METAL Always use the guards.guards. If If guards guards are notnot provided, provided, wear wear suitable suitable goggles as a protection against against flying fragments of of abrasive. abrasive. Keep Keep the wheelswheels roundround by by dressing dressing whenever required.required. Do Do not not force force work againstagainst a a cold cold wheel, wheel, but but GRINDING exercise light pressurepressure until until the the WHEEL wheel becomes warm. Always Always use a tooltool restrest when when the the work work permits. PresentPresent the the work work to to the wheelwheel eithereither straight straight in in or or at at a "drag" angle, angle, reserving reserving the the "gouge" angle angle for for sharpening sharpening and and other operationsoperations demanding demanding a a minimum burr.burr. WWWHEEL Odd Jobs.Jobs.—An—An almost endlessendless number number of of odd jobsjobs areare done done on on the the grinding grinding wheel. wheel. Smoothing aa weldedwelded joint, joint, as as in in Fig. Fig. 1, 1, is is typical ofof thisthis class class of of work. work. Cutting Cutting thin thin metal byby firstfirst folding folding it, it, as as in in Fig. Fig. 2, 2, and and then grindinggrinding through through the the fold, fold, as as in inFig. Fig. 3, 3, is another example. example. Fig. Fig. 6 6 shows shows how how the the edge of the wheelwheel isis usedused to to nick nick rod rod stock stock preparatory to to chiseling chiseling or or sawing. sawing. Most Most offhand grindinggrinding is is done done on on the the face face of of the the wheel. When grindinggrinding is is done done on on the the flat flat sides of a straightstraight wheel, wheel, use use care care to to wear wear the wheelwheel smoothsmooth since since a a rough rough or or grooved grooved side can bebe veryvery dangerousdangerous on on certain certain jobs. jobs. Position of Tool Rest.—ARest. —A level tool rest set a littlelittle belowbelow thethe center center of of the the wheel, wheel, as shownshown inin Fig.Fig. 4, 4, isis inin the the most most practical practical [ 16 ]]

CHAPTER SIXSIX HOW TO I SHARPEN TOOLS

General. — — Two operations are necessary GRINDING Two operations are necessary WHEEL in sharpening most most tools: tools: (1) (1) the the edge edge is is ground to to the the proper proper shape shape on on the the grinder, grinder, (2) the edgeedge isis honedhoned to to perfect perfect sharpness sharpness on a suitablesuitable oilstone. oilstone. The The grinding grinding wheel wheel 0 0 PVEr used shouldshould bebe an an aluminum aluminum oxide oxide wheel, wheel, REMOVE NICKS BY TIL'T TOOLREST R TOOTIL'T TOOL R T PUSHING CHISEL about 60-grit,60-grit, and and of of medium medium hardness. hardness. irre.mort. sine WHEEL ININRoemaBuEiIvVREEtlb TO Keep the wheelwheel properlyproperly dressed. dressed. A A revolv- revolv- THE ing diskdisk typetype dresserdresser (see (see page page 24) 24) can can be be used satisfactorily. In In grinding, grinding, keep keep the the tool cool by constantly dipping dipping in in water; water; temper is is beingbeing drawn drawn when when blue blue spots spots ap- ap- pear onon thethe edge edge of of the the tool. tool. High High speed speed steel is best groundground entirely entirely dry, dry, using using a a very light feedfeed andand stopping stopping be- be- tween cutscuts toto allowallow the the tool tool to to air air cool. TheThe use use of of a awhite white aluminum aluminum MOVEIsEL oxide wheel willwill permit a a heavier heavier EVENEVENLY Y feed without overheating.overheating. `AACROSSCCESS FFACE OF Wood Chisels.Chisels. — — Wood Wood chisels chisels WHEEL . should bebe hollowhollow ground.ground. Project Project the chiselchisel straightstraight into into the the wheel wheel to remove nicks,nicks, as as shown shown in in Fig. Fig . 27 Tool grinding is is done done on on A Ye10 °BEVEL BEVEL IS IS 1; then.then. adjustadjust the the tool tool rest rest to to the the OBTAINED BY an aluminum oxide oxide required position position to to grind grind the the bevel, bevel, MAKING BEVEL BEVEL wheel, with thethe edge edge ofof TWICE.TWICE THETHE the tool againstagainst thethe di- di- Fig. 2, working thethe chisel chisel squarely squarely HOLLOW THICKNESS GROUND OF CHISEL rection ofof rotation.rotation. Lower Lower across thethe faceface ofof thethe wheel, wheel, as as drowing shows shows honinghoning shown inin Fig.Fig. 4.4. WorkedWorked on on the the methods. faceface of the wheel,wheel, thethe bevelbevel willwill have aa slightslight hollow,hollow, making making it it A 2e20° BEVEL 20° BEVEL A 30*° BEVEL easy to hone toto aa perfect perfect edge edge sev- sev- CAN BE BE USED USEDCRUMBLES CRUMBLES STANDS UPUP IN eral timestimes beforebefore regrinding regrinding again again FOR SOFTWOOD ONON HARDWOODHARDWOOD becomes necessary. necessary. TheThe bevel bevel

BEVEL should bebe aboutabout 30 30 degrees, degrees, this this BURR being obtained by by making making the the bevel bevel twice the thicknessthickness of of the the chisel, chisel, as shown inin Fig.Fig. 5. 5. AA 2020 degreedegree bevel can bebe usedused for for softwood, softwood, but but GRINDING FORMS FORMS A A CLEARANCE BURR ONON CHISELCHISEL EDGE EDGE this thinthin wedge wedge will will crumble crumble on on WHEN HONED BEVELBEVEL hardwood, as as pictured pictured in in Fig. Fig. 6.6 BECOMES TOO 700 LONG THE CHISELCHISEL SHOULD SHOULD Honing. — — Either Either an an aluminum aluminum BE REGROUND oxide or aa siliconsilicon carbidecarbide oilstone oilstone will give good results inin honing honing or or whetting thethe chisel chisel edge edge after after grinding. TheThe stone should alwaysalways be be oiled, oiled, the the purpose purpose of this being toto floatfloat the the particles particles of metal soso thatthat they they will will not not be- be- come embedded in in the the stone. stone. Use Use a thin oiloil oror kerosene. kerosene. Wipe Wipe the the stone afterafter using. using. Honing Honing is is neces- neces- sary becausebecause grinding grinding forms forms a a burr at at the the chisel chisel edge, edge, as as shown shown

THE BURR CAN 1.Ir in Fig.Fig. 7.7. ToTo removeremove the the burr, burr, HONING REMOVES REMOVES BE REMOVED place the chiselchisel diagonallydiagonally across across THE BURR ANDAND 121BY BY HONINGTHE HONINGTHE BRINGS CHISELCHISEL TO TO CHISEL ON ON THE THE the stone,stone, asas shownshown in in Fig. Fig. 8, 8, and and A KEEN EDGEEDGE NANDHAND stroke backwardbackward and and forward, forward, [[ 17 11 in Fig. 11 on the previous page andand thisthis isis the correct technique for chisels, plane GRINDWAD PLANC. PLANE IRONSIRONS AT 30°30* irons, knives, etc. ThisThis methodmethod givesgives aa AND NONE HONE / AT 3S• clean edge with a minimum amount of IN labor. When the honed bevel becomes too THE JACK PLANEPLANE BLADE long through repeated whettings, Fig.Fig. 12,12, ISIS SLIGHTLY ROUNDEDROUNDED 1 chisel should be reground. Figs. 13 and 14

NONE picture the common method ofof handhand honing.honing. GGRINDING I , ANGLE Fig. 15 shows standard test for sharpness— the chisel should "bite" on thethe thumbthumb .nail. irons should be Plane Irons.Irons.—Plane— Plane irons are sharpened CORNER slightly rounded;rounded; all others .T/L411.1. 70.4111/411/41 the same as wood chisels. A bevelbevel ofof 3030 are ground straightstraight withwith a degrees and a honing angle of 35 degrees SMOOTHING PLANES PLANES ARE ARE slight roundround at at the the corners. corners. GROUND STRAIGHTSTRAIGHT is satisfactory in most cases.cases. TheThe cornerscorners

A 45. 40t r

KEEP EDGESEDGES KEEP 25 ROUND FOR POINT ONON COVE CUTSCUTS CENTER- •• LINE 35°POR HARD- WOOD

SKEW GOUGE SPEAR PO PO NT NT FLAT NOSENOSE ROUND NOSE PARTING TOOL GRINDING ANGLES FOR TOOLS Bevels on wood turning tools should be ground flat. Simple jigs, as atat left,left, sim- bearing do w n with both plify thethe work. hands. The heel of the chisel should be a slight distance of the plane iron should be above the surface of the slightly rounded. Mechanical de-de- stone as shown in Fig. 99 vices to hold the plane iron or Next, turn the chisel over and chisel at the proper angle when stroke the back on thethe stone.stone. grinding are advantageous. making certain to keep thethe Wood Turning Tools. — Some tool perfectly level, as shownshown wood turning tools are not hol-hol- in Fig. 10. AlternateAlternate thethe low ground. Instead,Instead, thethe bevelsbevels honing on bevel and back un- are perfectly flat andand shouldshould bebe til the burr is completely re-re- kept flat during honing. Any sec-sec- moved. ondary bevel on a skew, for ex- It will now be noted that ample, will prevent it from being honing puts a secondary used satisfactorily in turning.turning. bevel on the chisel, as shown where the heel of the bevel must act as a fulcrum.

The Skew Chisel.Chisel.—The— The bevel of the skew chisel is double andand hashas an included angle of 25 toto 3535 de-de- grees. Grinding can be done on the disk sander, or on the side of a straight or recessed grinding wheel. The chisel can be held freehand, but better results will be obtained with a simple guide block, as shown in Fig. 1. Holding thethe chisel first against one of the beveled guideguide blocks and then the other, as shown in Figs. 2 and 3. will bring each of the bevels to the required angle. In honing. main-main- tain the same bevel.bevel.

The Parting Tool.Tool.—Make— Make a suitable guide block to present the parting tooltool toto thethe side of the grinding wheel. A grinding wheel mounted on the circular saw offers a convenient method of working since thethe bevel angle can be set on the miter gage.gage. [[ 18 ]]

The gouge is sharpened byby rolling rolling on on Lathe Tool BitsBits—Lathe— Lathe tool either aa cupcup oror straight straight wheel. wheel. bits areare sharpenedsharpened offhand, offhand, as shown inin thethe lower lower photo photo being heldheld inin the the hand hand on the oppositeopposite page. page. The The to present the the tool tool at at the the proper angle angle to to the the side side of of Darting tool tool can can also also be be hol- hol- the grindinggrinding wheel. wheel. A A light light low ground ifif desired.desired. touch onon thethe grinding grinding wheel wheel

The Gouge.Gouge.—Simplest— Simplest of all is all that is is usuallyusually required required methods ofof sharpeningsharpening the the to bring the the bit bit to to a akeen keen gouge is to use aa cupcup wheelwheel edge. Maintain the the original original on the lathe,lathe, rotating rotating the the bevels, or, ifif workingworking blank blank chisel inside thethe wheel,wheel, asas stock, followfollow the anglesangles forfor shown inin Fig.Fig. 1.1. TheThe curved curved 11/4/4 inch inch bits bits given given in in the the surface ofof thethe cup cup wheel wheel drawing below. below. Handling Handling lessens the amountamount of of rolling rolling during grinding grinding is is simplified simplified necessary andand makes makes grind grind If the bitbit is is held held in in the the tool tool ing quitequite simple.simple. Lacking Lacking the the holder. asas shown shown in in Fig. Fig. 6 6 cup wheel,wheel, thethe samesame general general Small abrasiveabrasive sticks sticks can can be be method cancan be be employed employed by by used to advantageadvantage for for touch- touch- turning a a wedge-shaped wedge-shaped re- re- up sharpening,sharpening, es es p p e eci ci a a1- 1- cess in a block ofof hard-hard- ly when thisthis isis donedone during during wood. Fed withwith 60-grit 60-grit the coursecourse ofof aa lathelathe job. job. abrasive grains grains combined combined with grease,grease, thethe wood wood block block works works just just the the same asas cupcup grinding grinding wheel. wheel. The The gouge gouge can alsoalso bebe groundground by by rolling rolling the the bevel bevel on on the faceface ofof thethe wheel,wheel, asas in in Fig. Fig. 2 2 or or on on the the side of the wheel.wheel. Fig.Fig. 3.3. InIn all all cases cases the the roll roll must bebe justjust a a little little less less than than that that of of a fulla full half-circle. Special sharpeningsharpening stones stones are are required required for for honing thethe gouge. gouge. The The best best type type is is hollow hollow on one sideside andand round round on on the the other other side— side— made especiallyespecially for for honing honing gouges. gouges. Fig. Fig. 4 4 shows this stonestone in in use. use. The The round round edge edge of of the stonestone cancan be be conveniently conveniently used used to to cut cut the burrburr on on the the inside inside flat flat edge edge of of the the gouge, gouge, Lathe tooltool bits bits are are ground ground freehand, freehand, the the bit bit being being or aa slipslip stonestone can can be be used used for for this this purpose. purpose. mounted inin the the tool tool holder holder as as shown shown above. above. Drawing Drawing as shown inin Fig.Fig. 5.5. below shows grinding angles angles for for lathe lathe tool tool bits. bits.

_i__}._. _A__ 4 + _i__ * .1—-1— TOP'TOP VIEWViEN.. . TOP VIEWVIEWAll11111111/ Allill. .:2"5-31-12"-1.. 5-31 ..r•r.-— VV END —

'° k.. SIDE VIEWVIEW SIDE VIEWVIEW R-1— LEFT CORNER, CORNER- 11 `,28,?T.Y6,28,`?T.Y6 TOOL BITBIT

.••• merlon, ,,ROuNo,...- OUNO e TOP VIEW 1414*° TOP VIEWVIEW TOOLTOOL TOP VIEW Secr/oNSecr/aw \\' / I_33•4-a2.- 11 \ ....t...... FINISHING .1 —A- SiD VIEW//, *4 ...9'')43° / TOOL BITBIT ...... i),irg; ?k? ,....,.... SIDE WV.WV., U WV — ------f—,..j 1 \\._90go .'"- 3.- L1 3S1..3S1.. `

GRINDING ANGLES FORFOR. LATHE LATHE TOOL TOOL BITS BITS BEST RESULTS WILL WILL BE BE OBTAINED OBTAINED BY BY USING USING EXACT EXACT SHAVES SHAVES SHOWN) SHOWN)

[ 19 11

ROUND EOGEEOGE GRINDING WHEEL. WHEEI. NAIL SERVES AS GUIDE TO BRING EACHEACH TOOTH INTOINTO CLAMPP GRINDING STOPS, POSITION-POSITION-. SLIDESLIOE RESItREST, FEEDPEED .

SAW BLBLADE ADE LEVEL WITHW ITH LATHE CENTE,I,CENTC,,

AIL PIVOT

GaiNOTEETrjI44., AT Y4 PITCH IF SAWSAW ISIS GUMMEDGUMMED FREE- FREE- 2-1-6111/V HAND, THETHE DEPTH DEPTH OF OF GULLETS SIS FIRST FIRST MARKED MARKED

Above, simplesimple automatic automatic method method of of gumming gumming and grinding circular circular saw saw blades. blades. Below, Below, grinding grinding a mortising chisel chisel on on the the lathe. lathe.

Circular Saws. — Saw blades cancan be be gummed freefree hand hand by by simply simply holding holding the the saw to thethe wheel.wheel. AA pencilpencil mark mark should should be be made aroundaround the the rim rim of of the the saw, saw, as as shown shown in Fig.Fig. 2,2, toto indicateindicate the the depth depth to to which which the gulletsgullets areare to to be be ground. ground. Grinding Grinding is is done onon aa narrow,narrow, round-edge round-edge wheel. wheel. An automatic set-up set-up for for grinding grinding and and gumming cancan be be made made on on the the lathe lathe with with the useuse ofof thethe slideslide rest, rest, as as shown shown in in Fig. Fig. 1. The grindinggrinding wheel wheel should should be be dressed dressed to the requiredrequired gullet gullet shape, shape, and and the the slide slide rest adjustedadjusted so so that that the the wheel wheel will will be be in in alignment to to cut cut a a quarter-pitch quarter-pitch tooth, tooth, as as shown inin thethe circlecircle inset, inset, Fig. Fig. 2. 2. Grinding Grinding is done byby feedingfeeding thethe saw saw into into the the wheel wheel by means ofof thethe slide slide rest rest feed. feed. A A nail nail in in the workwork tabletable provides provides a astop stop so so that that each each wet-or-dry abrasive abrasive paper. paper. The The method method of of tooth isis accuratelyaccurately aligned aligned for for grinding. grinding. A A working is is shownshown in in Fig. Fig. 3, 3, the the chisel chisel being being clamp fittedfitted across across the the slide slide rest rest base base pro- pro- centered onon the the lathe lathe tailstock tailstock center center and and vides a stopstop forfor depth. depth. Each Each tooth tooth is isground ground projected into into the the revolving revolving wheel wheel or or abra- abra- in turn.turn. The The saw saw should should be be free free from from gum gum sive-covered woodwood form.form. AA squaresquare abra- abra- which might causecause an an inaccurate inaccurate setting setting sive stick oror filefile cancan be be used used to to clean clean out out against thethe guide guide pin. pin. After After the the gullets gullets the corners.corners. and toothtooth faces faces are are ground. ground. the the position position of of the slideslide restrest can can be be changed changed to to grind grind the the Grinding Jointer Knives. —— Jointer knives knives backs ofof thethe teeth.teeth. Throughout Throughout the the whole whole are groundground on on an an angle angle of of 36 36 degrees, degrees, as as operation of of sharpening sharpening the the circular circular saw saw shown inin Fig.Fig. 11 onon the the opposite opposite page. page. When When by grinding, caution caution must must be be used used to to pre- pre- mounted inin the the cutterhead, cutterhead, the the rear rear edge edge vent burning. of the bevel shouldshould bebe about about 1 1/16/ 16 inch inch from from the surfacesurface ofof thethe cutterhead, cutterhead, as as in in Fig. Fig. 2. 2. Mortising Chisels.—The internal surface surface of of Since the knivesknives areare quite quite narrow, narrow, it itis is the mortisingmortising chisel chisel should should be be ground ground to to necessary forfor grinding grinding purposes purposes to to make make a a an includedincluded angle angle of of 78 78 degrees. degrees. The The sim- sim- holding block,block, thisthis being being made made by by running running plest method of of working working is is to to use use a asmall small in aa sawsaw cutcut with with the the block block in in one one of of the the grinding wheel wheel with with end end shank, shank, dressing dressing the the positions shownshown inin Fig. Fig. 3, 3, depending depending on on the the wheel to the requiredrequired angle. angle. Lacking Lacking the the method whichwhich will will be be used used in in grinding. grinding. The The wheel, a woodwood formform can can be be turned turned and and saw kerf usua.lyusua.ly will will be be a a snug snug fit fit for for the the then coatedcoated with with glue glue and and rolled rolled in in abrasive. abrasive, knife, but ifif anyany looseness looseness is is apparent, apparent, the the or, thethe formform can can be be covered covered with with 120-grit 120-grit knife can bebe heldheld secure secure by by means means of of screws screws [20][ 20 ]

I SCREW 11.1'Il NCCVAIVARR ItfTiGntf•C'FIGn"---KNIFE KNIFE HOLDERHOLDER FOR 22rOING.14A:140ING FIG.,FIG., KNIFE

CUTTING' KNIFEKNIFE VETCJAW STRAIGHT HOLDER-HOLDER

Fig. 6 shows one ofof thethe knivesknives being being sharpened on on the the grinder. grinder. The The tool tool rest rest is is adjusted to to the the required required angle, angle, and and a guide a guide block isis clampedclamped in in position position to to insure insure a a straight cut cut across across the the knife. knife. Each Each knife knife is worked inin turn,turn, making making a asingle, single, very very light cut.cut. AA stripstrip of of paper paper is is then then pasted pasted to the holdingholding block, block, the the purpose purpose of of this this being to setset thethe next next cut cut without without changing changing the originaloriginal position position of of the the guide guide block. block. Two or threethree very very light light cuts willwill usuallyusually bring bring all all of the knivesknives toto aa perfectperfect A number of different methodsmethods can edge. It cannotcannot be be stated stated be used in grinding jointer jointer knives. knives. InIn too strongly thatthat abrasive abrasive each case, grinding is is done dry.dry. Very cuts onon highhigh speedspeed steel steel light cuts cuts must must be takentaken to to avoid avoid knives must bebe light; light; heavy heavy burning. Cuts Cuts are are made made in in rotation rotation cuts willwill invariablyinvariably burn burn on all knivesknives untiluntil a a final final cut cut brings brings the knifeknife andand render render it ituse- use- each of the knives to a perfect edge.edge. less. The methodmethod of of grinding grinding jointer knivesknives on on the the drill drill press withwith aa cup cup wheel wheel is is shown inin Fig.Fig. 7,7, whilewhile Fig.Fig. 8 showsshows thethe operationoperation as as performed on on the the circular circular saw. The latterlatter method method can can also be usedused inin connection connection with the beltbelt or or disk disk sander. sander. Whatever method method is is used, used, best results will will be be obtained obtained if the grindinggrinding is is done done with with successive light cuts,cuts, takingtaking each knifeknife inin turnturn until until all all edges come up sharp.sharp.

Honing Knives.Knives.—Grinding— Grinding is not alwaysalways necessarynecessary to to sharpen the the jointer jointer since since STOP careful honinghoning at at regular regular BLOCK intervals will will maintainmaintain a a REAR sharp head head for for some some time. time. TAB[ To hone thethe knives,knives, partly partly cover aa finefine carborundumcarborundum stone withwith paperpaper so so it it will will REAR not markmark the the table, table, and and TA8LE place it onon thethe front front table, table, as shown inin Fig.Fig. 9.9. TurnTurn the cutterheadcutterhead until until the the stone stone rests rests fiat fiat on on the bevel,bevel, andand fix fix the the head head in in this this position position by clamping the the belt belt to to the the stand. stand. Whet Whet the knifeknife byby strokingstroking the the stone stone lengthwise lengthwise with thethe blade,blade, treating treating each each knife knife with with the samesame numbernumber of of strokes. strokes.

Jointing Knives.Knives.—Knives— Knives can bebe sharpenedsharpened and broughtbrought to to a atrue true cutting cutting circle circle by by theirtheir edges edges while while the the head head is isre- re- volving. In thisthis operation,operation, the the stone stone is is placed onon thethe rear rear table, table, as as shown shown in in Fig. Fig. [[ 21 ]] 10, and thethe table table lowered lowered until until the the stone stone barely touchestouches the the knives. knives. After After two two or or three jointingsjointings of of this this nature, nature, it itwill will be be necessary toto reconditionrecondition the the knives knives by by grinding in in order order to to maintain maintain back back clear- clear- ance. Setting JointerJointer Knives.Knives. — — After grinding,grinding, knives must bebe carefully carefully mounted mounted in in the the head OneOne ofof thethe best best methods methods of of doing doing this isis withwith aa magnet,magnet, as as shown shown in in Figs. Figs. 11 11 and 1212 onon thethe previous previous page. page. An An index index mark should should be be scribed scribed on on the the magnet magnet and and a stop blockblock should should be be clamped clamped to to the the front tabletable at at such such a aposition position as as to to bring bring the index mark in line with the cutting the index mark in line with the cutting Top, grinding jigilg inin useuse edge of the knifeknife whenwhen it it is is at at its its highest highest point. TheThe knifeknife is is placed placed in in its its slot slot and and is is Above, the jig with pulled upup to to the the required required level level by by the the jointer headhead removed.removed. magnet, afterafter which which the the setscrews setscrews are are tight- tight- Pillow blocksblocks should be ened OnceOnce thethe initial initial set-up set-up has has been been made, made, turned toto exact diameter. this methodmethod of of adjusting adjusting knives knives will will be be found found both accurateaccurate and and convenient, convenient, and and faster faster than wherewhere a a plain plain straight straight edge edge is isused. used. IY4/1 Grinding Knives inin Head.—KnivesHead.—Knives can be _L ground without without removal removal from from the the head head by by 3/4 the methodmethod shown shown on on this this page. page. The The com- com- r443-11%8 3 -1- plete head isis mountedmounted on on the the jig. jig. Saw Saw cuts cuts 5i-24 in thethe pulleypulley serveserve to to bring bring each each of of the the SCREW knives into thethe requiredrequired position position for for grind- grind- ing. TheThe jigjig isis boltedbolted to to the the drill drill press press table, table, grinding being being done done by by swinging swinging the the table table which isis supportedsupported on on a acolumn column collar. collar. An- An- other methodmethod of of grinding grinding the the complete complete head head is shown inin thethe headingheading to to this this chapter. chapter. This This makes useuse ofof aa flexibleflexible shaft shaft fitted fitted with with a a small grindinggrinding wheel. wheel. The The head head is isfixed fixed at thethe properproper position position to to maintain maintain the the bevel bevel by clamping thethe belt belt to to the the side side of of the the machine stand.stand. [[ 22 ]] CHAPTER SEVEN SEVEN GRINDING SHAPER CUTTERS

Rake Angle.Angle.—The— The rake angleangle of of anyany cutter cutter determines determines ,ts shapeshape andand other other characteristics. characteristics. As As shown shown in Fig.in Fig. 1, 1, a slanting lineline across across a a piece piece of of wood wood is is necessarily necessarily longer thanthan a a straight straight one. one. Applied Applied to toshaper shaper cutters, cutters, Fit cancan bebe seen,seen, Fig.Fig. 2, 2, thatthat the the length length of of the the cutter cutter work- work- HOW ANGLE AFFECTS LENGTH F ing onon anan angle,angle, B, B, must must be be greater greater than than if theif the cutter cutter worked straightstraight across across the the work, work, as asat atA. A.This This rake rake angle isis presentpresent in in all all shaper shaper cutters cutters and and is greatestis greatest when knivesknives areare mounted mounted in in a amoulding moulding head, head, as asshown shown in Fig.Fig. 3,3, wherewhere thethe angle angle is is approximately approximately 30 30 degrees. degrees.

It isis obviousobvious thatthat the the greater greater the the rake rake angle, angle, the the greater greater MOULDINGMOULoiNG HEAD, 1-WING the differencedifference between between the the shape shape of of the the knife knife and and the the - CUTTERCUTTER moulding itit cuts.cuts.

Amount of Bevel.Bevel.—Knives— Knives are beveledbeveled atat an an angle angle be- be- tween 3030 andand 45-degrees.45-degrees. It It can can be be seen, seen, Fig. Fig. 6, 6, that that a a 30° RAKE bevel which willwill provideprovide clearance clearance at at the the outer outer cutting cutting circle maymay notnot be be enough enough to to give give clearance clearance at atthe the inner inner cutting circle.circle. Examination Examination of of a afactory-sharpened factory-sharpened cut- cut- ter willwill showshow thatthat the the bevel bevel is is A KNIFE SNAPS greatest at at the the inner inner edges edges of of ------ the knife,knife, thusthus maintaining maintaining the the RAKE ANGLES SLOTTED COLLACOLLARR same amountamount of of clearance. clearance. e6L Portions ofof thethe knife knife parallel parallel CLEARANCE c‘"" with the lineline ofof travel,travel, such such as as o ;000.0.1ttnW ANA 0o 00o , the sides,sides, demanddemand only only a a min- min- BEVEL imum amountamount of of bevel bevel to to pro- pro- SIDE vide clearance. BEALBEVEL

Projected Shape. — The re- quired shape ofof anyany cuttercutter to to NO produce a a certain certain shapeshape can can Uy CLEARANCECLEARANCE - -

be obtained by by drawing drawing the the SAME.SAME •A moulding fullfull sizesize onon a a piece piece BEVEL BEVEL ISIS GREAT- B EST ON INNER -' of paper, as as shown shown in in Fig. Fig. 7. 7. EDGE OF KNIFEKNIFE q Along the edgeedge ofof thethe mould-mould- ing erect aa verticalvertical line, line, A. A. Be- Be- Above, factors governinggoverning the the knife knife low the moulding,moulding, draw draw a ahor- hor- shape. Left,Left, aa knife knife projection. projection. izontal line,line, B, B, and and where where A Drawing below below shows shows knife melting.

ROUND KNIFE II IS EDGEEDGE FINISHED •••••••— HOLDER IS II WHEEL KNIFE • • ;Li

I N SLIP g STONE IS

PATTERN intersects B B draw draw a aline, line, C, at the samesame angle as thethe rakerake angle angle of of the the cutter. cutter. Drop Drop lines from thethe moulding moulding shape shape to to the the line line C and.and. using using 0 asas a a center, center, carry carry these these f lines around to to line line B B on on the the onnosite onnosite MOULDING J,T1 side and thenthen nroject project them them upward upward Lines Lines D located atat allall points points where where the the vertical vertical PAPER PATTERN PATTERN lines cut thethe mouldingmoulding are are carried carried across across WITH ALLOW. ANCE MADE; the centercenter line line and and establish establish a seriesa series of of , FORFOR RAKE ANGL marks. which, which, when when joined, joined, show show the the shape shape of the cutter required required to to cut cut the the moulding moulding [[ 23 ]] STARSi AR WHEEL WHEEL SHAPE DRESSER.„DRESSER4 FOR GENERAL WORK - 'AuRi2'61€ GRINDING WHEEL

TOOL.TOOL 0 REST ICK DRESSER DRESSING WHEEL

The difference amounts to about 1/16 A starstar wheel dresser isis fast-cuttingfast-cutting while stick and diamond inch in depth where mouldingmoulding headhead cut-cut- dressers provide provide for for precisionprecision work.work. ters are being plotted and about half of this for three-wing cutters and slotted collars. For average work, thethe projected shape can be judged withwith fair accuracy without drawing. The basic rules to remember are (1) knives for cutting beads must be ground deep- er, and (2) knives for cutting coves must be ground fuller.

Making a Knife.Knife.—Figs.— Figs. 8 to 15 on the previous page show the variousvarious stepssteps in making a pair of knives for use with slotted collars. The required shape isis a full half-circle, as shown inin Fig.Fig. 9.9. A paper or metal pattern is made, as shown in Fig. 8, and, following thethe Use of Shaped basic rule, this is cut slightly deeper Wheels.—Wheels can than the shape of a truetrue circle.circle. Fig.Fig. be fashioned to any 10 shows the pattern shape being trans-trans- required shape byby us-us- ing a suitable dresser.dresser. The revolving wheel

CUTTER type is the fastest cut-cut- MOUNTED ting, but does not per-per- ON SPINDLE __ mit the precision which is possible with the silicon carbide stick type or the diamond dresser. The wheel type should be pushed straight into DRESS the wheel, while thethe stickstick oror dia-dia- WHEEL TO SHAPE mond work best at a drag angle, as GRiNpING G`41TLIWHEELG can be seen in Fig. 1. With a wheel cuTTER properly shaped, it is a simple mat- (( ter to grind any cuttercutter toto thethe samesame contour. Fig. 3 shows a three-wing LOCK .• cutter being ground. Stops and CUTTER AT PROPER • guides insures all wings being POSPOSITIONITION ground exactly the same. The use of a shaped wheel in a tool post grinder used on the lathe is shown in Figs. 4, 5 and 6.6. TheThe cuttercutter isis (erred to the knife blanks. The outer turned to the required position for the straight bevel is then ground, a suitablesuitable bevel, as in Fig. 6, and is then locked in method being as shown in Fig. 11 which this position by means of the index pin,pin, uses the lathe slide rest to set the required after which the cut can be made.made. angle. The curved portion ofof thethe knifeknife isis Sharpening Knifes. — Factory -- groundground then ground on a round edgeedge wheel,wheel, asas shaper knives with involute bevels should shown in Fig. 13, the tool rest being ad-ad- be sharpened by honing the flat side of the justed to provide the proper bevel. After cutting edge, as shown in Fig. 7. The in- grinding both knives, the shape is compared volute bevel will retain the samesame shapeshape re-re- and checked. readjustments mademade asas re-re- gardless of metal removed from the backback quired, after which the bevel is lightly side. Knives ground in the homeshop with honed, as in Fig. 15, to remove any burr a straight bevel can be resharpened in thethe left by the grinding. OnOn certaincertain shapes.shapes. same way, or, the bevel itself cancan bebe honed.honed. good use can be made of a cut-off wheelwheel toto Where the knife has an involute or curved remove excess knife stock,stock, therebythereby eliminat-eliminat- bevel, however, no grinding or honing ing tedious grinding. should be done on thethe bevel.bevel. [[ 24 ]] CHAPTER EIGHT EIGHT GRINDING TWIST DRILLS

Point Angle.—The two most im-im- • -DRILL POINT portant features features of of drill drill grinding grinding ;,e-• GAGEGAGE CUTTING are (1)(1) thethe point point angle, angle, and and (2) (2) the the LIP lip clearance. The The point point angle angle has has been established at at 59 59 degrees degrees for for general work,work, and and this this angle angle should should 9„, be maintained. It It is is easily easily checked checked 9° with aa drill-pointdrill-point gage. gage. Gages Gages in in OVER 59. a variety ofof stylesstyles cancan be be pur- pur- chased atat a a nominal nominal cost, cost, or, or, the the worker can can make make his his own own from from sheet metal.metal. The The markings markings on on the the O edge, which cancan bebe seenseen in in Figs. Figs. 1, 1, 2 and 33 needneed notnot be be exact exact since since 0 0 j they areare usedused only only to to check check the the CORRECT POINT POINT ANGLE ANGLE POINTPOINT ANGLE ANGLE TOO TOO POINT ANGLEANGLE TOO TOO S $9°. THIS IS MOSTMOST GREAT- DOES DOES NOT NOT SMALL- REQUIRES REQUIRES length ofof oneone liplip againstagainst the the other. other. EFFICIENT POINT POINT FOR FOR CENTERCENTER EASILY-DOES EASILY-DOES MORE DOWER DOWER TO TO In use,use, thethe drill drill body body is is held held ALL.ALL•AROVND ROUND WORK WORK NOT TRACK IN PUNCH MARK OPERATE against thethe edge edge of of the the gage, gage, and inin suchsuch a a position position that that Point angleangle andand IlpIlp the angularangular edge edge is is over over the the clearance areare thethe two two cutting liplip of of thethe drill. drill. The The factors whichwhich enter enter in- in- gage will then showshow whetherwhether to the grinding of of or notnot thethe point, point, or, or, rather, rather, drills. AA point point angle angle one edge of the point,point, is is "on "on of 5959 degreesdegrees and and a the 59."59." Fig.Fig. 1 1 shows shows a a drill drill lip clearanceclearance ofof fromfrom with thethe correctcorrect point point angle. angle. 12 to I5-degrees givegive

Fig. 2 shows drill withwith point point POINT ON ON CENTER CENTER BUT BUT LIP ANGLESANGLES TN TN E E SAME SAME best results for for general angle whichwhich isis tootoo great;great; LIP ANGLES ANGLES OIFFERENT OIFFERENT BUT POINTPOINT OFF-CENTER OFF-CENTER work. Fig. 3 shows aa drilldrill with with a a point angleangle tootoo small. small. Besides Besides being being ground ground HEELREEL OF OF CLEARANCE to the correctcorrect angle, angle, both both lips lips must must be be CUTTING LIPLIP exactly thethe samesame length. length. What What happens happens when thethe liplip anglesangles are are different different or or of of un- un- equal lengthlength is is shown shown in in Fig. Fig. 4 and Fig.Fig. 5.5. CUTTINGEletIT ING It cancan bebe seen seen that that the the resulting resulting hole hole will will LIP CUTTINCuTTIN4 be out ofof roundround and and larger larger than than the the drill. drill. O CLEARANC V V Lip Clearance. — Like any otherother cutting cutting 1 tool, there mustmust be be clearance clearance behind behind the the DRILL POINT POINT MUST HAVE CLEARANCE 1/42I cutting edgeedge beforebefore the the drill drill can can cut. cut. This This AT EVERY PART PART OF clearance can can be be readily readily seen seen on on a aproperly- properly- 0 THETHE MOLEHOLE IT IT CUTSCUBS ground drill drill by by using using the the drill-point drill-point gage, gage, LILIPP CLEARANCE placing itit overover the the heel heel of of the the point, point, as as LOTTING shown inin Fig.Fig. 6.6. ItIt will will be be noted noted that that the the LIP angle herehere is is 1212 degreesdegrees less less than than the the lip lip angle, andand thisthis is is the the proper proper clearance clearance for for the averageaverage drill—from drill—from 12 12 to to 15 15 degrees. degrees. • O® 0 Clearance can can also also be be observed observed by by holding holding CLEARANCE CORRECT- CORRECT- WRONGWRONG -HEEL WRONG- RUBS AT the drilldrill as as in in Fig. Fig. 8 8 and and noting noting the the differ- differ- LIPS CUT AT X RUBS AT X X-LIPS CANNOTCANNOT CUT CUT ence between thethe lip lip and and heel heel of of the the point. point. Two horizontal sections sections of of a a drill drill point point are are part of of the the heel heel rubs rubs against against the the conic conic shown inin Fig.Fig. 7.7. ItIt can can be be seen seen that that there there recess, Fig. 11,11, the lipslips cannotcannot cut. cut. must bebe clearanceclearance behind behind the the cutting cutting lips lips Drill Grinding.Grinding.—With—With a fair understandingunderstanding at everyevery partpart of of the the conic conic recess recess which which the the of point angleangle andand lip lip clearance, clearance, the the worker worker drill cuts.cuts. WithWith clearance clearance properly properly ground ground can nownow attemptattempt to to grind grind a drill.a drill. Even Even on, the drilldrill cuts cuts at at the the cutting cutting lips, lips, leaving leaving though thethe theory theory has has been been mastered, mastered, it isit is every partpart of of the the point point behind behind the the lips lips in in still somewhat ofof aa trick trick to to grind grind a drilla drill the clear.clear. Fig.Fig. 99 showsshows thethe correct correct clear- clear- offhand andand arrive arrive at at the the proper proper point. point. Ex- Ex- ance. Fig.Fig. 1010 showsshows justjust the the reverse reverse of of perienced mechanics,mechanics, through through long long practice, practice, correct clearance—the clearance—the drill drill rubs rubs at atthe the heel heel go through the the motions motions almost almost mechanical- mechanical- and thethe lips lips cannot cannot cut. cut. Likewise, Likewise, if ifany any ly, grinding points points which which are are extremely extremely ac- [[ 25 ]] EIK WHEEL, REST

16

POSITION AT FINISH

Drawing above above showsshows successivesuccessive steps inin sharpening drill onon aa wheelwheel mounted in the lathe. 59 degrees with the side of the grinding wheel, as shownshown inin Fig.Fig. 18.18. MarkMark off off 2 series of parallel guide lines, each of these being on an angle of 12 degrees (the clear- ance angle) with the guide block, as shown. Now, if the cutting lip is placed against the side of the grinding wheel, with the body ofof the drill against the guide block, as shown in Fig. 19, the proper point angle will be obtained. From this position thethe drilldrill isis rotated about one-sixth of a full turn, atat the same time moving to a position parallelparallel with the penciled guide lines, as shown in Fig. 20. Each lip is treated in turn, check- ing with the drill gagegage to see that both are the same exact length. If desired, the grinding procedure can be re- versed, starting at the A simple method of grinding utilizesutilizes a guide position shown in Fig.Fig. block to set the point angle. 20. This has the advan- tage that the surface curate without the use of any me- being ground can be chanical guides or other aids. The seen at all times, but it worker who only occasional grinds has the disadvantage a drill should always use some form of producing a heavier of guide. Figs. 12 to 16 inclusive show one method of working. In burr at the cutting lips. this example, grinding is done on the In any case, care must lathe. The tool rest is firstfirst setset byby be exercised not to ro- using the drill gage in the manner tate the drill too much,much, shown in Figs. 12 and 13. Now, if the since over rotation will lip of the drill is presented toto thethe bring the lip on the op- wheel while the body of the drill isis posite side into contact at right angles to the rest, the point with the wheel, with angle will be exactly as required,required, asas the result that the can be seen in Figs. 14 and 15. From grinding must be done this starting position, the drill isis ro-ro- all over again. One or tated about one-sixth of a full turn, at two light twists on each the same time dropping the end about lip will usually bringbring 12 degrees to give the required clear-clear- the drill to a sharpsharr ance. The proper swing isis bestbest ac-ac- point. Touch-up grind quired by swinging a properly-ground ing can be done by drill against the wheel, keeping the grinding the lips light- ground surface in contact with the ly and rotating about wheel and noting the movements re-re- one-eighth of a turn for quired to produce this surface.surface. clearance. T his will Instead of dropping the drill to give a clean edge and grind the lip clearance, the drill can can be done several be swung horizontally to produce the times before the condi- same effect. To grind drills in this tion shown inin Fig.Fig. 1111 manner, clamp a wood tabletable toto thethe results, when the drill tool rest of the grinder and on this FIN;31-4 POSITION will demand grinding table nail a guide block at an angle of overover the the entire entire surface. surface.

[26 ] OUNED EDGEDG ED WHEEL

Above, web thinning with with round-edge round-edge wheel. wheel. ness, providing the the metal metal is isre-re- Right, web web thinned thinned on on square-edge square-edge wheel. wheel. moved from thethe immediate immediate point point Various mechanicalmechanical drill drill grinders. grinders. only. Where the the shop shop owner owner does does both self-poweredself-powered and and for for attach- attach- not possesspossess aa suitablesuitable round-edge round-edge ment toto aa standardstandard grinder, grinder, can can be be wheel, the webweb cancan bebe thinned thinned on on purchased. Where Where considerable considerable drill drill an ordinaryordinary square-face square-face wheel. wheel. In In grinding must must be be done, done, it itis is usually usually this formform of of web web thinning, thinning, most most of of a savings ofof bothboth time time and and money money the grindinggrinding is is done done on on the the back back to use oneone ofof thesethese units.units. The The of the lips,lips, thethe grindgrind being being carried carried usual devicedevice willwill handlehandle drills drills from from up toto thethe center center of of the the point point on on 1/32 to 1/2-inch1/2-inch diameter.diameter. each side,side, asas shownshown in in Fig Fig 5. 5.

Drill for Brass.Brass.—For— For drilling brassbrass and coppercopper it it will will be be found found advantageous advantageous squAREsqREuA EDGE to modify thethe cuttingcutting edges edges of of the the drill. drill. WHEEL The effecteffect toto bebe obtainedobtained is is shown shown somewhat exaggeratedexaggerated in in Fig. Fig. 7, 7, which which shows howhow thethe cutting cutting edge edge of of the the lip lip is ground off. off. This This makes makes the the edge edge scrape scrape rather than than cut, cut, and and reduces reduces the the tendency tendency of the drilldrill toto "dig "dig in" in" in in brass brass and and other other soft metals.metals. This This form form of of grinding grinding can can be done onon aa fine-gritfine-grit wheel, wheel, as as shown shown in in Fig. Fig. 6. Very littlelittle metalmetal is is ground ground off, off, just just a a few thousandths of of an an inch, inch, and and for for this this reason itit isis oftenoften better better to to flatten flatten the the cut- cut- ting edgeedge withwith aa small small sharpening sharpening stone. stone.

Special Grinding.Grinding.—While—While a point angleangle of of 59 degrees andand a a clearance clearance angle angle of of from from 12 to 15-degrees hashas beenbeen found found best best for for aver- aver- age work, bestbest efficiency efficiency is is obtained obtained if if drills drills are specially-groundspecially-ground for for the the work work to to be be done. ForFor example,example, fiber fiber takes takes a adrill drill with with a point angleangle of of but but 30 30 degrees, degrees, while while man- man- ganese steel requiresrequires a a 75-degree 75-degree point point angle. TheThe countlesscountless drill-grinding drill-grinding varia- varia- tions nownow inin generalgeneral use use are are of of undoubted undoubted Drilling in in brass brass and and other other soft soft metal metal is bestis best done done with with value toto thethe productionproduction shop shop worker, worker, but but a drill ground ground in in the the manner manner shown shown above. above. are seldomseldom usefuluseful in in the the home home shop. shop.

Web Thinning.Thinning.—As—As shown inin Fig.Fig. 3,3, thethe Wheels for Drill Grinding.—AsGrinding. — As listed inin web of the drilldrill becomes becomes thicker thicker as as it itap- ap- the appendix,appendix, the the purified purified form form of of aluminum aluminum proaches thethe shank. shank. It It follows, follows, therefore, therefore, oxide (white inin color)color) makesmakes the the best best wheel wheel that thethe point point of of the the drill drill becomes becomes thicker thicker for grindinggrinding high high speed speed drills. drills. It Itis isnot not as as as the drilldrill is is ground ground down down and and resharp- resharp-tough asas regularregular aluminum aluminum oxide, oxide, but but runs runs ened, necessitatingnecessitating more more power power to to force force it it cooler and isis practicallypractically self-dressing. self-dressing. Sec- Sec- through the the work. work. To To partly partly eliminate eliminate this this ond choicechoice forfor highhigh speed speed drills drills and and first first heavy end thrust,thrust, the the web web of of the the drill drill should should choice for generalgeneral drill drill grinding grinding is is the the reg- reg- be thinned, as as shown shown in in Fig. Fig. 4. This opera- ular typetype of of aluminum aluminum oxide. oxide. In In either either case, case, tion isis usuallyusually donedone on on a a round-face round-face grind- grind- the gritgrit shouldshould be be about about No. No. 60 60 and and the the ing wheel, thethe drilldrill being being held held so so that that the the grade mediummedium hard. hard. The The best best wheel wheel shape shape wheel cuts inin thethe flutes. flutes. The The web web can can be be is a recessed center,center, but but good good work work can can be be thinned to to about about one-half one-half its its original original thick- thick- done onon thethe sideside of of a a straight straight wheel. wheel. [[ 27 ]] CHAPTER NINENINE BUFFING and POLISHING

Metals, plasticsplastics and .lacquer• coated surfaces cancan bebe broughtbrought to a smooth andand flawlessflawless fin-fin- ish by the application of suit•suit- ably-graded abrasive grains carried onon a polishing wheel .

LEATHER CEMENTED ANDAND PEGGED IN PLACEPLACE

0 7 '441:' • SOLID LEATHER POLISHING WHEEL WHEEL

LEATHER- COVERED GLUE ISIs APPLIEDAPPLI WOOD WHEEL TO THEThe Rion OF OF THE WHEELWHEEL Polishing.—Polishing is is the the general general A Setting Up Polishing G2ARWI E 441/41 term appliedapplied to to the the complete complete process process Wheels. — The old abra-abra- of removing tool tool marks, marks, scratches, scratches, sive is first cleanedcleaned offoff etc., from metals metals and and other other substances substances by applyingapplying an an abrasive abrasive to produce aa high-lusterhigh-luster finish. finish. The The stick aboutabout three three num- num- process is divided intointo three three distinct distinct bers coarsercoarser than than the the parts. FirstFirst of of these these is is roughing. roughing. abrasive onon the the wheel, wheel, as as Roughing is is done done dry dry with with abrasives abrasives WHEE COATEDtExtet yi5 shown inin Fig.Fig. 8. 8. The in gritgrit numbers numbers from from 40 40 to to 80. 80. Dry Dry RROLLINGOLLING v ABRASIVE GRAirtSGRAINS wheel fining or or fine fine wheeling, wheeling, as as the the second second Tt5,TESTING.SLATINt.E FOR wheel is then coatedcoated withwith operation is is called, called, can can also also be be done done dry, but but is is often often done done on on a agreased greased wheel. Grits used used areare from from No. No. 120 120 to 180. Finishing, alsoalso calledcalled oilingoiling and buffing, is is the the final final operation. operation. It It is done with finefine grain grain abrasives abrasives com- com- bined with lard lard oil, oil, tallow, tallow, beeswax. beeswax. water. etc.etc. TheThe exact exact size size ofof grain grain used in all operationsoperations will will depend depend up- up- on the original finish finish on on the the work work and and the the desired finish on on the the completed completed product. product.

Polishing Wheels.Wheels.—The—The first operationoperation of of roughing can can be be done done on on a a solid solid grinding grinding wheel. However, because because this this is is hard hard and and has no flexibility, polishing polishing is is usually usually done done on leatherleather or or canvas canvas wheels wheels made made espe- espe- cially forfor this this purpose. purpose. If If the the work work is isa aflat flat surface, aa solidsolid leatherleather or or leather-covered leather-covered wood wheel cancan bebe used; ifif the the work work is is curved, itit will will demand demand a cementeda cemented canvas canvas wheel or otherother type type which which has has the the required required flexibility.

[ 28 ]] THE RIPPLE BUFFBUCTI PARALLEL RUNS WITHEITHERwrn4 EITHER HARDWARD OR OR SOFT SOFT EDGE DEPENDINGDEPENDING CONCENTRICCONCENTRIC ON NOW IT IS IS MOUNTED ONON THE SPINDLESPINDLE 7--,724p,u0HARD

RIPPLE

METALTEETH

• KIZ691GAT;B ING WHEtLWHEE.1 BUFFING WHEEL RAKERAKE

WRONG 110 •• POSITIONPOSITION \ OF WORK

LOOSE WORKING BUFFS AREA

Buffing is is the the final final polishing polishing operation operation and and is is clone with softsoft cloth cloth or or leather leather wheels. wheels. glue, as inin Fig.Fig. 5,5, afterafter which which it it is is rolled andand pounded pounded in in the the abrasive abrasive grains, asas shownshown in in Fig. Fig. 6. 6. Ordinar- Ordinar- ily, one coat ofof abrasiveabrasive is is enough, enough, but twotwo oror more more coats coats can can be be applied applied to roughing wheels wheels to to lengthen lengthen their their period ofof service.service. Each Each coat coat should should be completely drydry before before the the next next is is ap- ap- plied. After thethe wheel wheel is is dry, dry, it it should should be be

balanced, as as shown shown in in Fig. Fig. 7. 7. If If any any heavy heavy \ RIGHTRIGHT POSITION spots areare found, found, they they should should be be corrected corrected OF WORK by nailing smallsmall pieces pieces of of lead lead to to the the wheel wheel or byby anyany otherother method method which which gives gives the the grains andand shortens shortens the the life life of of the the wheel. wheel. desired result.result. Apply grease oror other other lubricant lubricant if ifrequired. required. An occasional applicationapplication of of lump lump pumice Concerning Glue. — Animal hidehide ground ground glue is commonly usedused forfor applying applying abra- abra- will clean thethe wheelwheel ifif itit becomes becomes clogged. clogged . sives to polishing wheels.wheels. ItIt should should be be Work systematicallysystematically over over the the area area to tobe be soaked inin coldcold water water from from two two to to four four polished, inspectinginspecting the the work work frequently frequently for for hours, andand is is then then brought brought to toa heata heat of of140 140 defects which mustmust be be worked worked out. out. degrees F.F. inin aa suitable suitable gluepot. gluepot. Use Use definite definite Fine Wheeling.Wheeling.—Fine— Fine wheeling is done thethe weights of water and and glue. glue. Equal Equal parts, parts, by by same asas roughingroughing except except finer finer abrasive abrasive weight, is the rightright consistency consistency for for abrasive abrasive grains areare used. used. Also, Also, at at this this stage stage there there • grains fromfrom No. No. 20 20 to to No. No. 50. 50. Finer Finer grains grains is a greater use use of of the the softer softer polishing polishing demand a a thinner thinner glue. glue. 60 60 to to 70-grit 70-grit takes takes wheels, and frequentfrequent use use of of grease grease or or other other a 40-60 mix (glue-water), 8080 toto 120-grit120-grit takes takes lubricant to to prevent prevent the the wheel wheel from from clog. clog. 33-67, while very finefine abrasivesabrasives from from 150 150 to to ging. 220-grit willwill requirerequire 20 20 percent percent glue glue to to 80 80 Buffing.—Buffs are mademade of of disks disks of of mus- mus- percent water. water. Wheels Wheels should should set set at atleast least lin, felt, flannel,flannel, leather.leather. etc., etc., and and are are sewed sewed 48 hours beforebefore they they are are used. used. Instead Instead of of in aa widewide varietyvariety of of patterns patterns as as shown shown in in using glue,glue, manymany workers workers prefer prefer special special Figs. iu to 13,13, toto produceproduce hard hard or or soft soft polishing cementscements mademade for for this this purpose. purpose. wheels. The looseloose buffbuff (stitched(stitched once once These have thethe advantage advantage of of being being already already around the the hole) hole) as as shown shown in inFig. Fig. 10, 10, is isa mixed, and requirerequire a ashorter shorter drying drying time. time. popular style. style. The The ripple ripple buff buff can can be be made made How to Polish. — The workwork is is presented presented to run with with either either a ahard hard or orsoft soft edge edge by by freehand to to the the wheel wheel and and on on the the outer outer reversing it it on on the the spindle, spindle, as as shown shown in in quarter area area of of the the wheel wheel surface, surface, as asshown shown Fig. 9. As inin polishing,polishing, the the work work must must bebe in Figs.Figs. 11 andand 15. 15. Avoid Avoid using using too too much much done onon thethe lowerlower side side of of the the wheel, wheel, as as oressure. asas this this tears tears nut nut the the abrasive abrasive shown inin Fig.Fig. 18.18. WorkWork presented presented as as shown shown [[ 291 either withwith or or without without the the backing backing plate plate depending onon the the nature nature of of the the work. work. In In all respects, thethe belt belt can can be be treated treated the the same asas aa polishingpolishing wheel, wheel, and and can can be be coated coated with abrasiveabrasive grains grains or or buffing buffing compound. compound.

Buffing Compounds. — Buffing compounds.compounds are variousvarious natural natural abrasives, abrasives, such such as asemery, emery, tripoli, pumice,pumice, crocus, crocus, lime lime and and rouge, rouge, which areare combined combined with with a asuitable suitable wax or or grease toto formform a a mixture mixture which which can can be be readily appliedapplied to to the the revolving revolving buff. buff. The The compound should should be be applied applied lightly lightly and and frequently to to the the buff buff as as the the work work pro- pro- gresses, asas shownshown in in Fig. Fig. 19. 19. The The worker worker can makemake hishis own own buffing buffing compounds compounds by by melting beeswaxbeeswax in in a a double double boiler, boiler, as as . shown inin Fig.Fig. 20,20, andand then then adding adding the the I abrasive until until a a thick thick paste paste is isformed. formed. The The I molten massmass isis thenthen poured poured in- in- to cardboard tubes, tubes, as as in in Fig. Fig. 21, or mademade intointo cakes, cakes, and and BEESWAX9E SWAX when cold isis readyready for for use. use. All All of the various standard standard abra- abra- The buffing compound compound is is applied applied lightly lightly and and . r e) ) sives can alsoalso bebe purchasedpurchased frequently to to the the revolving revolving buffing buffing wheel. wheel. ready made.made. Very Very fine fine abra- abra- sives can bebe bondedbonded with with oil oil by the dotteddotted lines, lines, Fig. Fig. 18, 18, will will or water. be torn fromfrom the the hands hands with with con- con- Other than than polishing polishing metals, metals, siderable force. force. The The edges edges of of the the 0ro buffing wheelswheels chargedcharged with with buff shouldshould be be kept kept clean clean and and MIX ABRASIVE WITH WA% suitable compoundscompounds are are used used round. FrayedFrayed edges edges can can be be dressed dressed down withwith aa buffingbuffing wheel wheel rake, rake, for polishingpolishing plastics,plastics, lacquered lacquered Fig. 16, while the buffbuff is is running.running. surfaces, barebare wood, wood, ivory, ivory, Any rough edge,edge, such such as as a a house- house- horn, etc.etc. InIn all all cases, cases, such such POUR INTOINTO easily-obtained abrasivesabrasives as as hold food ,grater, can can be be used used to to CARDBOARD..CARDBOARD dress buffs.buffs. CYLINDERCYLINDER pumice andand rouge rouge will will usually usually do good work.work. BenzineBenzine or or Strapping Belts.Belts.—Belts— Belts of muslin, lacquer thinner thinner will will remove remove felt, leather, etc., etc., can can be be run run on on the the any filmfilm ofof compoundcompound left left on on belt sander,sander, as as shown shown in in Fig. Fig. 14,14 the workwork afterafter buffing. buffing.

BUFFING AND POLISHINGPOLISHING SCHEDULESSCHEDULES

MATERIAL METHOD OF OF WORKING WORKING

Polish at 5,5005,500 s.f.m.s.f.m. usingusing Nos. Nos. 80, 80, 120120 andand 180-grits. 180-grits. All wheels over 120-grit120-grit ALUMINUM should bebe wellwell greased.greased. Buff at 7,5007,500 s.f.m.,s.f.m., usingusing tripolitripoli for for the the first first buffing buffing and finishingfinishing with with red red rouge. rouge.

BRASS Polish at 6,0006,000 s.f.m.s.f.m. usingusing Nos. Nos. 80, 80, 120 120 and 180-grits. The 80-grit is necessary only for roughrough castings. castings. Buff Buff with with tripoli tripoli or or emery emery at aat speed a speed of aboutof about 5,500 5,500 s.f.m. s.f.m.

Same schedule asas brass.brass. COPPER Fine-grit wheelswheels should should be be greased. greased. Avoid heavy pressure since since copper copper heats heats quickly quickly and and holds holds heat heat longer longer than than other other metals. metals.

CAST Use grits 120, 150 and 180.180. The two coarsercoarser grits grits can can be be run run dry. dry. Buff at 7,500 IRON s.f.m. Buff with 220220 toto 240-grit240-grit silicon silicon carbide carbide applied applied to to a greaseda greased rag rag wheel. wheel.

LACQUERED Use a lacquer suitable suitable for for buffing. buffing. Buff at 6,0006,000 s.f.m.,s.f.m., usingusing any any reliable reliable brand brand SURFACES of lacquer buffingbuffing compound. compound.

NICKELED Buff at 7,5007,500 s.f.m.s.f.m. usingusing tripoli tripoli and and lime. lime. A perfect finishfinish is is necessarynecessary if if the the SURFACES work isis toto bebe chromiumchromium plated. plated.

Polish with 280-grit280-grit silicon silicon carbide. carbide. Buff with 400400 and 500-grit 500-grit silicon silicon carbide carbide on greased wheels.wheels. Finish withwith redred or or green green rouge. rouge.

Polish at 7,5007,500 s.f.m.,s.f.m., usingusing aluminum aluminum oxide oxide grits grits Nos. Nos. 90 90 and and 120 120 dry dry and and 180 180 greased. Buff with tripolitripoli or or a avery very fine fine grit grit STEEL aluminum oxide. oxide. For a mirror finish, buffbuff withwith greengreen rouge. rouge. For satin finish,finish, buff buff with with pumice pumice on on a aTampico Tampico brush.

[[ 30 ]] CHAPTER TEN HOW TO USEUSE SANDING DRUMS

Sanding Drums.—SandingDrums.—Sanding drums ofof vari-vari- ous sizes are extensivelyextensively used used for for edge edge work, andand can can be be satisfactorily satisfactorily worked worked on on the drilldrill press,press, lathe, lathe, flexible flexible shaft, shaft, or or direct- direct- coupled toto aa motormotor shaft. shaft. The The size size most most commonly usedused measuresmeasures 3 3 inches inches in in diam- diam- eter andand should should be be run run at at a speeda speed of ofabout about 1800 R. P.P. M.M. WithinWithin reasonable reasonable limits, limits, the higherhigher the the drum drum speed speed the the smoother smoother the the finish. ExcessiveExcessive speed,speed, however,however, causes causes overheating, and, and, where where wood wood is is being being fin- fin- ished, thethe heatheat extracts extracts a agummy gummy pitch pitch from from the workwork which which quickly quickly clogs clogs the the abrasive abrasive sleeve. Sanding onon Lathe. Lathe. — — Drums usedused on on the the lathe areare fitted fitted with with taper taper sh, sit, tks tks or orscrew- screw- on fittings toto permitpermit fastening fastening to to the the lathe lathe headstock. SandingSanding can can be be done done freehand, freehand, but wherewhere edge edge work work is is being being done, done, as as in in Fig. 1, a vertical support support greatly greatly simplifies simplifies the work.work. Drums Drums with with taper taper shanks shanks should should be safeguarded from from coming coming loose loose by by sup- sup- A vertical sandingsanding table table clamped clamped to to the the bed bed of ofthe the lathe lathe porting the the end end with with the the tailstock, tailstock, using using a a permits accurateaccurate sanding sanding of of curved curved edges. edges. sixty degree plainplain center. center. Another Another n method ofof fastening usesuses aa 11/4/4 inch inch Wee i: !F diameter stud stud which which is is turned turned into into the holehole inin thethe end end of of the the shank, shank, the oppositeopposite endend being being held held secure secure by means ofof aa washerwasher and and wing wing nut, asas shownshown in in Figs. Figs. 2 2 and and 3. 3.

Taper shank shank drums drums are are securely securely held held by bymeans means of a stud fittingfitting through through the the headstock. headstock.

Narrow-Face Drums.Drums. —— Standard sanding drumsdrums measure measure 3 3inches inches long and havehave a a projecting projecting nut nut on on the freefree end.end. Narrow-faceNarrow-face drums drums are 11 inchinch widewide and and are are flush flush on on the bottom,bottom, the the tightening tightening nut nut be- be- ing onon thethe shankshank end, end, as as shown shown in in Fig. 4. All standard operations operations can bebe donedone with with these these drums, drums, the the face face width ofof 11 inchinch beingbeing sufficient sufficient to to handle handle average 3/4/4 inchinch thickthick work. work. The The flush flush bot- bot- tom alsoalso permitspermits the the finishing finishing of of inside inside corners, as as shown shown in in the the lower lower photo. photo. When When doing thisthis kindkind of of work, work, it it is is advisable advisable to to mount thethe sleeve sleeve so so that that it it projects projects about about inch beyondbeyond thethe bottom bottom of of the the drum, drum, as as shown inin Fig.Fig. 5,5, inin orderorder to to prevent prevent the the drum bottom bottom from from burning burning the the work. work. Nar- Nar- row-face drumsdrums are are fitted fitted with with a speciala special tri- tri- shape shankshank which which permits permits mounting mounting in in either i inch inch collets or or three-jaw three-jaw chucks, chucks, as shown inin Fig.Fig. 6.6. [[ 31 ]] spindle. A second table can bebe used, or the regular table can be swung around under the drum. Fig. 3 shows work being sanded with the drill table in a vertical position. Furniture legs which are to be fittedfitted toto a round column can be cut to shape by using a sanding drum in this manner. Pattern Sanding.—TheSanding.—The most troublesome featurefeature inin edgeedge sand-sand- ing with a drum isis thatthat ifif thethe oper-oper- ator holds the work a moment too long at any one spot, thethe drumdrum im-im- mediately cuts into the work, caus- ing a ridge. This can be avoided and perfect work done if a pattern is used as a guide, as shown in Fig. 7. The pattern is a full-size template of the desired shape, with edges perfectly finished. It is fitted with two or more Above, using a sanding table.table. Right,Right, anchor points. These can be drum mounted directdirect to motor shaft. wood screws, with the projecting end filed to a Sanding on Drill Press. Press. — thin, flat p o i n t, as Drums used on the drill presspress shown inin Fig.Fig. 4. The run in a vertical position work is fitted to the most useful for average work.work. pattern, the anchor Good use can be made of points holding it in fences, pivot pins, and other place. Band sawing is jigs toto guideguide thethe workwork al-al- then done, keeping though most operations can about -1'-g116 inch inch outside outside be done freehand. Small the pattern, as shown drums will work inside thethe in Fig. 5. Fig. 66 showsshows opening in the drill press how the drill press table table, while larger sizes can is fitted with a hard- be worked by swinging the wood or metal ring. drill table to one side. Fig. When the pattern is 1 shows a useful sanding pressed against the col- table. It has holes in it to lar, the drum cuts thethe accommodate the various size work down to the same drums, so that the whole sur- size as the pattern. face of the drum can be util- ized by projecting the drum Pattern sanding, as shownshown through the hole provided below, eliminates ridge marks I when irregular curves are be. for it. Another worthy idea ing worked. is shown in Fig. 2, which shows how a sanding drum can be carried on the lower end of the drill press motor

[[ 32 ]] CHAPTER ELEVENELEVEN How to Use CUT-OFF WHEELS

General Use.—Cut-offUse.—Cut-off abrasive wheels wheels in in thicknesses fromfrom 1/32 1/32 to to 5/32-inch 5/32-inch are are used used for sawingsawing allall typestypes of of materials materials including including

metals, stone,stone, andand glass. glass. The The wheels wheels are are LAMP resinoid, shellacshellac or or rubber rubber bonded bonded to toper- per- mit aa slightslight measuremeasure of of flexibility. flexibility. The The work cancan bebe done done either either wet wet or or dry. dry. The The wet method isis considerablyconsiderably faster faster and and shows less wheel wear,wear, butbut the the dry dry method method of cutting isis quitequite suitable suitable for for average average homeshop work.work. The The surface surface speed speed of of dry dry wheels should bebe aboutabout 7,500 7,500 feet feet per per min- min- ute, whilewhile wetwet wheelswheels showshow bestbest results results at 6,000 s.f.m. Wheels can bebe run onon anyany spindle providingproviding only only that that they they are are proper- proper- ly mounted andand well well guarded. guarded. In In every every case, case, however, washerswashers of of blotting paperpaper should should be used onon eithereither side. side. These areare generallygenerally furnished as as part part of of the the wheel. CuttingCuffing Thin • Wall Above, cutting steel steel tubing tubing with with an an abrasive abrasive wheel on the circular saw. saw. Tubing. — One of the most commoncommon uses uses of of abrasive cut-offcut-off wheels wheels the mitermiter gage gage clamp clamp attachment, attachment, is the cuttingcutting ofof tubing.tubing. as shown inin thethe photo photo and and diagram diagram In thisthis operation,operation, as as above. NoticeNotice thatthat the the work work is is done onon thethe circularcircular ea. 11 supported on on both both sides, sides, a aslot slot in in saw, it isis advisableadvisable toto the blockblock permittingpermitting passage passage of of the the hold thethe tubingtubing in in a a wheel. suitable veevee block,block, thethe CuttingCuffing Solid Sfock.Stock.—Solid— Solid stock block being heldheld to to the the is cut inin muchmuch the the same same manner manner miter gagegage by by means means of of ill6t...... i...._ - .1 as wood isis sawedsawed onon thethe circular circular Some form ofof guideguide must must al- al- saw. Some formform ofof guideguide is is al- al- ways be used when cutting-off ways necessary. AA suitablesuitable guard guard on the gr,cler. should bebe used.used. If If a a special special abra- abra-

1 [[ 33 ]] at any dime store. The guard plate is used in actual operation andand isis removed in the picture only toto show how the bottom of the wheelwheel runs in the . The use of the grinder for cutting-off has one serious drawback in thatthat thethe pro-pro- jection of the motor limits the size of stock which can be worked toto about V2 inches square. The belt-belt- drive grinder, however, has much more clearance.

Diamond Blades.Blades.—Glass,—Glass, hard al- loys and gems are commonly cut with the use of a diamond cut-off wheel. This is a metal wheel with diamond chips impregnated around the rim. Ready-made wheels, six inches in diameter, cost about $5.$5. One carat of diamond (value about $2) will charge the home-home- made wheel. This is made from a disk of 1/161/16 inch thick steel. Nicks A breadbread pan fittedfitted below the grind-grind- er holds the coolantcoolant whenwhen wetwet cut-cut- cut around the wheel receive the ting oror grindinggrinding isis toto bebe done. bort mixed with vaseline, the chips then being sealed inin placeplace byby roll-roll- sive wheel guard is not ing with a hardened steelsteel roller,roller, available, the regular saw as shown in Figs. 2 and 3. Dia- guard can be fitted with a mond blades are generally run at sheet metal hood to serve somewhat lower speeds than other the purpose. Any metal cut types of cut-off wheels, and must with a dry wheel will dis- always be run wet. The grain sizesize color through heat gener- VI6 GROOVE for average work should be 50- ated by the wheel, but this ROLLER grit. surface film is easily re- -1" O Cutting-OffCutting - Off on Lathe.Lathe.—The— The lathe moved by sanding with fine performs excellently as a cut-off abrasive paper. Right, making a . Below, cut- True Wheels Essential.Essential.—A— A Right, making a diamond blade. Below, cut- balanced wheel with a clean ting-off onon thethe lathe. edge is necessary for good cutting.cutting. WheelsWheels out of round will wobble andand cutcut consider-consider- ably wider than their own thickness. The use of a stick type dresser atat regularregular in-in- tervals will keep the wheel inin goodgood condi-condi- tion. In using a stick dresser on cut-off wheels, do not be afraid to apply consider-consider- able pressure against the wheel. Wheel dressing is not a cutting operation, but a tearing away of the abrasive grains by pressing against the wheel with an abrasive which is somewhat harder than the wheel itself.

Cutting-OffCutting - Off onon Grinder. — CutCut-off- off wheels can be used successfully on thethe grinder.grinder. The work must never, however, be worked freehand. A simple method of working isis to turn the center link ofof thethe tooltool restrest up-up- side down, allowing it to pivot atat the bot-bot- tom. Work can then be clampedclamped toto thethe tooltool rest and swung into the wheel, asas shownshown inin machine, especially on small work which the lower photo on the previousprevious page.page. InIn permits the use of the slide rest for feeding . another method of working, a table withwith aa as shown in Fig. 4. Either the slide rest slot to accommodate a sliding block can be feed can be used or the work table can fitted to the tool rest or clamped toto thethe be advanced by hand, guided by the bar , as shown on the previous page.page. which works in the slot ofof thethe slideslide rest.rest. This provides a guide similar to the miter A special table can be made if desired soso gage used on the circular saw. A simple that work can be cutcut atat thethe toptop ofof thethe blade,blade, method of wet cutting is shown inin thethe much the same as on the circular saw. Wet photo above, and is quite clean in operation. cutting is more readily done on the lathe The water pan is a bread pan. obtainable than on any other machine. 34

CHAPTER TWELVE Miscellaneous ABRADING OPERATIONS

Tumbling.—TumblingTumbling. — Tumbling is extensively usedused in industryindustry for for finishing finishing small small metal metal parts. parts. The processprocess cancan be be worked worked successfully successfully in in the smallsmall shop,shop, using using a a wooden wooden barrel barrel driven onon the the outboard outboard end end of of the the lathe. lathe. The barrelbarrel should should be be made made from from hard hard , maple, as shown inin Fig.Fig. 2,2, andand must must be be solidly solidly constructed, especially especially if if castings castings of of fair fair size size are toto bebe tumbled. tumbled. If If tumbling tumbling is isdone done wet, wet, as is sometimes thethe case, case, the the barrel barrel must must also be watertight.watertight. One One section section is is hinged hinged to form aa lid.lid. The The barrel barrel is isfastened fastened to toa a 15-inch diameterdiameter hardwood hardwood pulley pulley The workwork isis generallygenerally processed processed through through a cycle of at leastleast threethree operations. operations. The The first isis anan ashingashing or or scouring scouring operation operation which removes allall tooltool marks marks and and rough- rough- ness on the surfacesurface of of the the article article and and ren- ren- ders itit smooth.smooth. The The second second stage stage is is the the burnishing or or semi-polishing semi-polishing operation, operation, while the finalfinal stagestage is is the the true true polishing polishing operation. The The time time required required to totumble tumble finish runsruns from from 16 16 to to 48 48 hours hours for thethe threethree operations. operations. The The Tumbling with with abrasive abrasive grains grains makes makes a good finish forfor metal metal or or plastic plastic first stagestage ofof thethe process process de-de- parts. AA cycle cycle of of three three operations operations mands the the most most time; time; is generally required.required. the finalfinal polishpolish can can be be done inin aa veryvery short short 6" FACEPLATE FACEPLATE time providingproviding the the pre- pre- vious abrading has has been been 2° 'PULLEYPULLEY - 1 0 done thoroughly.thoroughly. The The 11 % abrasive used used is is in in loose grain form, the La. loose grain form, the TUMBLING grit beingbeing somewhat somewhat BARREL coarser than than used used in in wheel polishing. Nos.Nos. 24 to 36 are usedused for for roughing; 40 40 to to 80 80 for for 2°. semi-polishing; 100 100 andand IS DIA. WOOD 60 RR.P.M. Scratch brushingbrushing at at slaw slaw speed speed pro- pro- PULLEY COUNTER- duces a serrated finish.finish. A A high high speed speed SHAFT gives a satin finish. DRIVE 120 for polishing.polishing. The The exact exact abrasive abrasive varies varies considerably, depending depending upon upon the the work work be- be- ing tumbled.tumbled. The The barrel barrel is isloaded loaded between between • one-third and and two-thirds two-thirds full, full, the the work work com com prising aboutabout 60 60 percent percent of of the the load load while while the balancebalance is is made made up up with with the the abrasive abrasive grains andand small small pegs pegs of of the the material material being being tumbled. Slow Slow speedspeed is is absolutely absolutely essen- essen- tial andand should should never never exceed exceed 90 90 R. R. P. P. M.M. AA suitable drivedrive which which does does not not interfere interfere with with the lathelathe drive drive proper proper is isshown shown in in Fig. Fig. 3. 3.

Spun Finish.Finish.—An— An attractive finish finish for for metal metal work isis obtainedobtained by by scratch scratch brushing brushing at at slow speed, asas shownshown inin the the lower lower photo. photo. A stick coated withwith coarse coarse abrasive abrasive grains grains can alsoalso bebe used.used. The The finish finish consists consists of of a a it [[ 35 ]] Engine Finish.Finish.—An—An engine or spot finish is produced on the drill press by the methods shown in Figs. 2, 3, and 4. Fig. 2 shows how a dowel stick is cappedcapped withwith anan abra-abra- sive disk for this purpose. Instead of using an abrasive disk, the tip can be leather and the abrasive bonded with waxwax oror greasegrease andand fed to the work. The drill press should runrun about 1200 r.p.m. Solid abrasive sticks can be used, butbut requirerequire careful careful alignment. alignment. A tiny cup wheel, Fig. 3, makes aa ringring pat-pat- tern. Fig. 4 shows a good methodmethod ofof work.work. ing the engine finish. AA softwoodsoftwood doweldowel isis used. A strip of thin, hard brass with a hole through it is located on the drill table immediately below thethe dowel.dowel. TheThe workwork isis fed with a mixture of abrasive grains andand oil or water, the dowel abrading this into the metal. Internal Grinding. —Small holes can be ground by mounting an abrasive stick in a Above, grinding glassglass edges. DrawingDrawing at held in the lathe right showsshows various methods usedused inin pro-pro- tailstock, as shown in ducing on engine finish.finish. Fig. 5. The setover series of minute rings spun tailstock se t s the around the work, the depth of depth of cut. A small hand grinder can be the serrations depending uponupon the softness of the metal itself used for the same job, and the grit of the abrasive and also for a wide used. This abrasive treatment variety of other work. is extensively used asas aa finishfinish Other Lathe Opera- for spun aluminum projects.projects. tions. —— Other ex- amples of grinding Grinding Glass.Glass.—Glass— Glass edges jobs which can be can be ground to an almost per- done on the lathe are fect polish with the use ofof sili-sili- shown in Figs. 7 and con carbide abrasive used 8. Fig. 7 shows a on the disk sander, as shown in groove being run in Fig. 1. Standard 9 by 11 inch on a bushing, using a sheets of wet-or-dry paper can round edge wheel be cut into disks for occasional The same set-up with work of this nature. 120-grit straight wheel and gives a smooth, mat edge, while slide rest feed is used 220 to 320-grit brings up a very for surfacing cylin- good polish. The glass should ders. Fig. 8 shows a air cool between cuts.cuts. flat being worked on the end of a shaft. The lathe does not turn in this instance, but is locked by means of the index pin.pin. Tool post grinders worked on the slide rest are used for aa wide variety of lathe grinding jobs.jobs.

[[ 36 ]] Drilling Glass.—The drillingdrilling of of glass glass is is an an operation thatthat may may be be done done with with ease ease on on the drill press,press, although although difficult difficult by by any any other method.method. The The drill drill employed employed is isa a piece of brass tubingtubing with with an an outside outside diam- diam- eter equalequal toto the the size size of of the the hole hole to to be be drilled. TheThe tubingtubing should should be slotted withwith one cut, using a veryvery narrow narrow saw. saw. The The cut cut need not extendextend more more than than about about 1/4 1 /inch4 inch from thethe endend of of the the tube. tube. Similar Similar results results are effected byby notching notching the the end end of of the the tube tube in two oror threethree places. places. The The tube tube is isnot not sharpened inin anyany way way — — it it is is simply simply cut cut square onon thethe end,end, and and then then slotted slotted or or notched asas mentioned.mentioned. The The glass glass should should be be supported on on a a perfectly perfectly flat flat piece piece of of wood, wood, or, better, on on a a piece piece of of felt felt or or rubber. rubber. A A dam of putty is is built built around around the the place place where where the hole isis toto bebe drilled, drilled, or or a afelt felt ring ring can can be used forfor thethe same same purpose. purpose. The The well well is is fed with aa mixturemixture of of 80-grit 80-grit silicon silicon carbide carbide abrasive grainsgrains combined combined with with machine machine oil oil or turpentine.

Grinding Keyways.Keyways.—Keyways— Keyways and similar work can be done withwith smallsmall abrasive abrasive wheels mounted in in the the drill drill press. press. The The best best method ofof holdingholding and and feeding feeding the the work work is to employemploy the the lathe lathe slide slide rest. rest. This This is is easily fitted toto the the lathe lathe table table by by means means of of the same boltsbolts used used to to attach attach it to thethe lathe.lathe. An An under under view, view, showing the slideslide restrest being being fitted, isis shownshown in in Fig. Fig. 2. 2. Fig. 3 shows the keywaykeyway being cut. AA speedspeed of of 5,000 R. P. M. shouldshould bebe used. Wheel shapesshapes in in Top, drillingdrilling glass. glass. Photos Photos above above any size, abrasive,abrasive, or or grit grit and at leftleft show show use use ofof slide slide can be obtained readyready rest in drilldrill press press grinding. grinding. mounted onon shanksshanks which which can be held inin thethe drill drill as already describeddescribed or or press chuck.chuck. in any suitablesuitable jig.jig. The The slide rest permitspermits feed- feed- Surface Grinding.Grinding.—A—A 3- inch cup wheelwheel workedworked ing the workwork to to the the in the drilldrill presspress offers offers wheel, while work held held one of the bestbest methodsmethods stationary in in a a machin- machin- of surface grinding. TheThe ist's visevise oror simplesimple wood wood work cancan bebe held held by by the the , Fig.Fig. 4, is sur- lathe slideslide restrest mounted mounted faced byby feedingfeeding the the wheel to thethe work. work. Fair- Fair- ly large surfacessurfaces cancan be be covered byby using using a a drill drill press columncolumn collarcollar and and swinging the workwork below below the abrasive wheel, the same method as as de- de- scribed forfor grindinggrinding jointer knivesknives (see (see page page 22). Large workwork can can al- al- so be handled byby using using a a sanding disk inin thethe man- man- ner shown inin Fig.Fig. 5.5.

Grinding on Shaper. — Sanding and grindinggrinding can can be done onon thethe wood , usingusing sandingsanding drums, straightstraight wheels, wheels, cup wheels, andand anyany A cup wheelwheel mountedmounted in in the the drill press press will will handle handle a awide wide other formform of of grinding grinding variety of of surfacing surfacing operations. operations stone which cancan bebe fitted [[ 3737 1] Almost anyany tooltool cancan bebe adapted for abrasive work. Photos on this page show the shaper, bandband sawsaw andand lathelathe setset upup forfor sanding and grinding.grinding.

to the spindle. For most work,work, thethe speedspeed isis exces-exces- sive and should be reduced to about 5,000 R. P.P. M.M. This can be done by belting the shaper pulley to aa pulley fitted to the lower end of the drill press motor, lowering the drill head toto suit.suit. Figs.Figs. 11 andand 22 aboveabove show typical set-ups. The operation shownshown inin Fig.Fig. 2 requires the use of a wood table to bring the work approximately level with the top ofof thethe cupcup wheelwheel which is being used. Final adjustment asas wellwell asas feed is provided by the standard travel of the shaper spindle. Sanding on Band Saw.—The use of narrow abrasive belts on the band saw provides an excellent methodmethod of sanding edge work. Belts up to 1 inch wide can be used. Guides are provided for some band saws to permit the use of belts, but onon otherother sawssaws thethe worker can improvise simple guides.guides. AsAs farfar asas guides are concerned, the belt will work perfectly well without them. Ribbon abrasive belts in all standard widths and grain sizes are obtainable andand are easily spliced to suit the size of the band saw. Perfect tracking is assured by the upper tilting wheel of the saw, while the standard band saw adjustment permits tensioning. Sanding on Lathe.—The use of a sanding disk on the lathe is so well knownknown asas toto requirerequire littlelittle descrip-descrip- tion. Where the lathe isis notnot fittedfitted withwith aa sandingsanding table, a table can be made from wood, as shown in the drawing at right, and fitted with a pipe shank which can be accommodated in the tool rest base. All operations described in the chapter on the diskdisk sander can be worked with equal facility onon thethe lathe with this addition. AA groovegroove toto taketake thethe mitermiter gage can be run in on the table surface ifif desired.desired.

Sanding on Other Tools.—Almost any shop tool can be usedused forfor sand-sand- ing and grinding. Sanding disks work perfectly when mounted on the circular saw arbor;arbor; smallsmall sand-sand- ing drums are commonly used on the scroll saw; simple jigsjigs cancan bebe made for the lathe to permit the use of sanding belts. Where the work cannot be taken to the ma- chine, a flexible shaft suitable for handling sanding disks andand grind-grind- ing wheels can bebe usedused toto advan-advan- tage for many operations.operations. [38]

%b. APPENDIX

ABRASIVES AND ABRASIVE TERMS

Aluminum OxideOxide ...... An artificial abrasive, Oilstones . . General descriptive term applied with a base of the natural clay-like , to all abrasives when made into stones for bench Bauxite. Color, brown-gray to black; in purepure use. Corm, white. Hardness, 9.* Pumice . . . A natural abrasive Used for final Bond . .. . Clay or other substance which holds polishing, cutting down finishin4finishin4 coatscoats ofof var-var- abrasive grains together toto formform wheels,wheels, etc.etc. nish, etc. Several grades of fineness. Color, off- white. Hardness, 4. Crocus . A natural abrasive formed from oxide of iron. Color, purple. Used for fine polishing. Quartz Commonly called Flint. A natural Hardness, 2. Quartz abrasive Least expensive of all abrasives but Emery... A natural abrasive, being an impure very softsoft. Color, yellow. Hardness, 6.6. form of crystalline alumina. Much softersofter thanthan aluminum oxide. Color, dull black.black. Hardness,Hardness, 8.8. Roffensfone ... A natural abrasive. Negligible cutting action but good polisher. Color, off-white.off-white. Garnet . A natural abrasive mined in the Hardness, 3 United States. Extensively used in woodwork- ing. Color, red. Hardness, 7.7. Rouge . A natural abrasive in powder form.form. Graded fine, very fine, extra fine. Color, red; Glazed .. .. Said of a wheel or stone which also, green (chromium oxide). Hardness, 0. has become clogged with metal particles soso that it will notnot cut.cut. Silicon Carbide ... An artificial abrasive made Grade .. The resistance of the bond in a by fusing silica sand. Color, gray, green or grinding wheel to any force tending to pry the black. Hardness, 10. abrasive grains loose. Has nothing to do with the hardness of the abrasive itself.itself. Structure . The spacing of abrasive grains Grit . . in a grinding wheel. Usually represented by a The size of the abrasive grains, deter- number from 1 to 12, the smaller numbersnumbers indicat-indicat- mined by the number of grains which, endend toto ing close spacing ofof grains.grains. end, equals one inch.inch.

Lime .. .. A fine natural abrasive, used exten Tripoli . A silicious powder consisting of sively in the final polishing ofof brassbrass andand nickel.nickel. tiny skeletons. Color, pink. Graded. Used in Color, white. Hardness, 1.1. fine polishing. Hardness,Hardness, 5.5. *Numbers•Numbers given in this fablefable list list the the hardness hardness of theof the abrasives abrasives in sequence, in sequence, from 10 from (the 10 hardest) (the hardest) fofo 0 (the softest). The number has no gradinggrading value,value, butbut isis simplysimply usedused toto indicateindicate thethe hardnesshardness of the abrasives in descending order.order.

COATED ABRASIVEABRASIVE SELECTION SELECTION

MATERIAL ABRASIVE ROUGH FINISH FINE Hard Garnet or Alum. Oxide 221/2-11/21/2-11/2 '/2-1/0'/2-1/0 2/0-3/0 Soft Woods Garnet 111/241/2 4 1/0 2/0 Aluminum Alum. Oxide 40 60-80 1001130 Bakelite Alum. Oxide 36-40 60-80 100100 Cast Brass Silicon Carbide 36-40 60-80 80-120 Comp. Board Garnet 1111/2/2-11 11/2/2 1/0 Copper Alum. Oxide 40-50 80-100 100-120100-120 Cork A. 0. or Garnet 3 I I-0 Fiber Alum. Oxide 36 60-80 100100 Glass Silicon Carbide 50-60 100-120100-120 120-320120-320 Horn Garnet 111/21/2 11/2-1/0/2-1/0 2/0-3/0 Iron (Cast) Silicon Carbide 24-30 60-80 100100 Ivory Alum. Oxide 60-80 100-120100-120 120-280120-280 (removing) Flint 3-13-11/21/2 11/2-1/0/2-1/0 Plastic A. 0. or Garnet 50-80 120-180120-180 2402:46 . Steel Alum. Oxide 24-30 60-80 100100

COMPARATIVE GRAIN GRAIN SIZES SIZES

NO. GARNET FLINT EMERY NO. GARNET FLINT EMERY NO. GARNET FLINT EMERY 400 10/0 ... 150150 4/0 2/0 VI 40 1111/2/2 2 1/2/2 ... 320 9/0 ... Fi 120120 3/0 1/0 11 36 2 3 .. 280 8/0 ... F 100100 2/0 V: 1111/2/2 30 211/2/2 ... 240 7/0 3/0 80 1/0 1 2 24 3 ... 220 6/0 4/04i0 2/0 60 W: 111/2/2 Vs 20 331/21/2 ...... 180180 5/0 3/0 1/0 50 I 2 3 I 1616 4 ......

39 1 GRINDING WHEEL SELECTION*SELECTION*

WORK ABRASIVE GRIT GRADE BOND

Aluminum (surfacing)(surfacing) Alum. Oxide (White)(White) 46 Soft Vitrified

Aluminum (cutting-off)(cutting-off) ' Alum. Oxide 29 Hard Resinoid Brass (surfacing)(surfacing) Silicon Carbide 36 Medium Vitrified Brass (cutting-off)(cutting-off) Alum. Oxide 30 Very Hard Resinoid Cast IronIron Silicon Carbide 46 Soft Vitrified Chisels (woodworking) Alum. Oxide 60 Medium Vitrified Copper (surfacing)(surfacing) Silicon Carbide 60 Medium Vitrified Copper (cutting-off)(cutting-off) Silicon Carbide 36 Hard Rubber Cork Alum. Oxide (White)(White) 60 Soft Vitrified Cutters (moulding) (moulding) Alum. Oxide 60 Medium Vitrified Drills (sharpening) Alum. Oxide (White)(White) 60 Medium Vitrified Glass (grinding) Silicon Carbide (Green) (Green) 150150 Hard Vitrified Glass (cutting-off) Silicon Carbide (Green) (Green) 90 Hard Rubber Glass (cutting-off) Diamond 60 Medium Copper Leather Silicon Carbide 96 Soft Vitrified Plastic Silicon Carbide 60 Medium Rubber Rubber (hard) (hard) Silicon Carbide 46 Medium Resinoid Saws (gumming) Alum. Oxide 60 Medium Vitrified Steel (soft) Alum. Oxide 60 Medium Vitrified Stee, (high speed) Alum. Oxide (White)(White) 60 Soft Vitrified (cutting-off) Silicor Carbide 30 Hard Resinoid Tubes (steel) Alum. Oxide 60 Hard Rubber Welds (smoothing) Alum. Oxide 36 Hard Vitrified Wood (hard) Silicon Carbide 30 Soft Vitrified

** AdaptedAdapted from fables by The NortonNorton Company.Company.

Recommended Recommended WHEEL SPEEDSSPEEDS BELT andand DRUM SPEEDSSPEEDS Chisel Grinding Grinding 5,000-6,000 s.f.m . 48 inch abrasive belts belts 3 100 s.f.m. Cut-off Wheels Wheels 6,000-8,000 s.f.m 6 to 10-h. abrasive belts belts 2,800 s.f.m Surface GrindingGrinding 9,000-6,000 ss f.m.f.m. 10 to 16-ft. abrasive belts.. belts.. 2,900 s.f.m. Polishing 6,000-9,000 s.f.m. 98 inch inch polishing polishing belts belts 9,0009,000 s.f.m s.f.m

Polishing (soft(soft rubberrubber wheels) wheels) 9,000 s.f.m .. 3 inch drumsdrums (coarse (coarse grit grit abrasive). abrasive). 1,800 1,800 r.p.m r.p.m Buffing. ....... 6,000-9,000 s.f.m. 3 inch drumsdrums (fine (fine grit grit abrasive) abrasive) 2,900 r.p.m. r.p.m. Scratch Brushing Brushing (rough (rough finish) finish) 600 r.p.m. 1 inchinch drums (closed(closed coating) coating) 1,200 r.p.m. Scratch Brushing Brushing (satin (satin finish) finish) 9,000-6,000 9,000-6,000 s.f.m. s.f.m. 1 inchinch drums (open (open coating) coating) 1,800 r.p.m. General GrindingGrinding ...... 5,000-6,500 s.f.m. 10 toto 1212 inch inch abrasive abrasive disks disks 1,800 r.p.m.r.p.m. Internal Grinding Grinding 2 000-6,000 s.f.m. Abrasive disks . 4 500 s.f.m.

GRINDING WHEELWHEEL SPEEDS SPEEDS IN R.R. P.P. M. R P. M. FORFOR STATED STATED SURFACE SURFACE SPEED SPEED DIAMETER OF WHEEL 9000 s.f.m. 9500 s.f.m 5000 s.f.m. 5500 s.f.m. 6000 s.f.m. aim. 6500 s.f.m. 7000 s.f.m. 7500 s.f.m

1I 15,27915,279 17,18917,189 19,09819,098 21,008 22,918 24,828 26,737 28,647 2 7,639 8,599 9,599 10,50910,509 11,95911,959 12,91912,919 13,36813,368 14,32814,328 3 5,093 5,729 6,366 7,003 7,639 8,276 8,913 9,599

4 3,820 4,297 9,775 5,252 5,729 6,207 6,685 7,162 5 3,056 3.438 3,820 4,202 9,589 4,966 5,398 5,730 6 2,546 2,865 3,183 3,501 3,820 4,138 9,956 4,775

7 2,183 2,455 2,728 3,001 3,274 3,547 3,820 4,092 8 1,9101,910 2,148 2,387 2,626 2,865 3, 103 3,392 3,580 1010 1,5281,528 1,7191,719 1,9101,910 2,101 2,292 2,983 2,674 2,865

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