National Bureau of Standards Library, N.W. Bldg OCT 26 1380 U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS SCREW-THREAD STANDARDS FOR FEDERAL SERVICES 1957 Amends in part H28 (1944) (and in part its 1950 Supplement) HANDBOOK H28 (1957) —Part III THE NATIONAL BUREAU OF STANDARDS Functions and Activities The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in¬ vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau’s unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau’s work take the form of either actual equipment and devices or pub¬ lished papers. These papers appear either in the Bureau’s own series of publications or in the journals of professional and scientific societies. The Bureau itself publishes three periodicals available from the Government Printing Office: The Journal of Research, published in four separate sections, presents complete scientific and technical papers; the Technical News Bulletin presents summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions provide data for determining the best frequencies to use for radio communications throughout the world. There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series, Handbooks, Miscellaneous Publications, and Technical Notes. Information on the Bureau’s publications can be found in NBS Circular 460, Publications of the National Bureau of Standards ($1.25) and its Supplement ($1.50), available from the Superintendent of Documents, Government Printing Office, Washington 25, D.C. UNITED STATES DEPARTMENT OF COMMERCE • Frederick H. Mueller, Secretary NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director NATIONAL BUREAU OF STANDARDS HANDBOOK H28 (1957) SCREW-THREAD STANDARDS FOR FEDERAL SERVICES 1957 PART III ACME, STUB ACME, AND BUTTRESS THREADS ROLLED THREADS FOR SCREW SHELLS OF ELECTRIC LAMP HOLDERS AND UNASSEMBLED LAMP BASES MICROSCOPE OBJECTIVE AND NOSEPIECE THREADS SURVEYING INSTRUMENT MOUNTING THREADS PHOTOGRAPHIC EQUIPMENT THREADS ISO METRIC THREADS; MISCELLANEOUS THREADS CLASS 5 INTERFERENCE-FIT THREADS, TRIAL STANDARD WRENCH OPENINGS Amends in part H28 (1944) (and in part its 1950 Supplement) [Issued October 7, 1960] For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington 25, D.C. Price 60 cents Foreword This volume is the third of a series of three into which the 1957 edition of NBS Handbook H28 is divided. Part I, published in September 1957, includes standards for screw threads which are commonly applied to bolts, screws, nuts, and other similar fasteners. Such threads are variously designated as Unified, American, American National, and Unified Miniature threads. Part II, published in November 1959, includes standards for the follow¬ ing: pipe threads, including Dryseal pipe threads; gas cylinder valve outlet and inlet threads; hose coupling, including fire-hose coupling threads; and hose connections for welding equipment. Handbook H28 (1944) and the 1950 Supplement thereto are superseded by Parts I, II, and III of Handbook H28 (1957) and the Federal Specifications listed in appendix 6 of Part I of H28 (1957). A Supplement to the 1957 Handbook is in preparation, in order to make available revisions that have been developed subsequent to publication. These pertain primarily to the Unified thread standards. Archibald T. McPherson, Chairman, Interdepartmental Screw Thread Committee. PERSONNEL OF THE INTERDEPARTMENTAL SCREW THREAD COMMITTEE Representing the Department of Defense: Mr. Alden W. McDaniel, Mechanical and Engineering Programs Branch, Standardization Division, Armed Forces Supply Support Center, Department of Defense, Washington 25, D.C. Representing the Department of the Army: Mr. Eugene Von Loesch, Research and Development Division, Office of the Chief of Engineers, Department of the Army, Washington 25, D.C. Mr. M. L. Frueciitenicht, Gage Laboratory, Frankford Arsenal, Ordnance Corps, Department of the Army, Philadelphia 37, Pa. Representing the Department of the Navy: Mr. Tames W. Jenkins, Metallurgical and Mechanical Branch, Research Division (Code 343), Bureau of Ships, Department of the Navy, Washington 25, D.C. Mr. J. E. Walter, Engineering Department, U.S. Naval Weapons Plant, Washington 25, D.C. Representing the Department of the Air Force: Mr. Joseph W. Evans, WWDPFE, Wright Air Development Division, Wright-Patterson Air Force Base, Ohio. Mr. Francis L. Calkins, WWDXSS, Wright Air Development Division, Wright-Patterson Air Force Base, Ohio. Representing the Department of Commerce: Dr. Archibald T. McPherson, chairman, Associate Director, National Bureau of Standards, Washington 25, D.C. Mr. Irvin H. Fullmer, secretary, Chief, Engineering Metrology Section, Metrology Division, National Bureau of Standards, Washington 25, D.C. Liaison Representatives of Sectional Committees Organized Under the Procedure of the Ameri¬ can Standards Association and Sponsored by The American Society of Mechanical Engi¬ neers and the Society of Automotive Engineers, Inc., or the American Gas Association: Mr. Richard B. Belford, Technical Adviser, Industrial Fasteners Institute, 1517 Terminal Tower, Cleveland 13, Ohio. (Member of ASA Committees B1 and B18.) Mr. H. C. Erdman, Technical Adviser to Pres., The National Screw & Manufacturing Co., 2440 E. 75th St., Cleve¬ land 4, Ohio. (Member of ASA Committees B1 and B18.) Mr. Ernest S. Heldmann, Chief Engineer, Holo-Krome Screw Corp., 31 Brooks St., Hartford 10, Conn. (Rep¬ resenting ASA Committee B18.) Mr. Russell F. Holmes, Technical Assistant, Engineering Standards Section, General Motors Technical Center, General Motors Corp., Detroit 2, Mich. (Member of ASA Committees B1 and B2.) Mr. Milton A. Schultheis, Staff Engineer, Hughes Aircraft Co., Bldg. 6, Mail Sta. T2057, Culver City, Calif. (Member of ASA Committee Bl.) Mr. Frank Tisch, Voi-Shan Manufacturing Co., division of Voi-Shan Industries, Inc., 8463 Higuera St., Culver City, Calif. (Member of ASA Committee BL) Mr. W. G. Waltermire, Chief Products Engineer, The Lamson & Sessions Company, 5000 Tiedeman Rd., Cleve¬ land 9, Ohio. (Member of ASA Committees Bl, B2, and B18.) APPROVAL BY THE SECTARIES OF DEFENSE AMD COMMERCE The accompanying Handbook H28 (1957), Part III, on screw-thread standards for Federal Services, submitted by the Interdepartmental Screw Thread Committee, is hereby approved for use by the Departments of Defense and Commerce. / ^ —- For the Secretary of Commerce Secretary of Defense Contents Page Page Foreword_ ii Section XVIII. Photographic equipment threads. 41 Personnel of the Interdepartmental Screw Thread 1. Tripod connections for Committee_ ii American cameras; %— Approval by the Secretaries of Defense and Com¬ 20UNC—1A/1B threads merce_ iii (PH3.6)_ 41 Section XII. Acme threads- 1 2. Tripod connections for 1. General and historical_ 1 European cameras; 3/g—■ 2. Specifications for Acme form 16UNC—1A/1B (PH3.7).. 42 of thread_ 1 3. Threads for attaching 3. Standard Acme thread se¬ mounted lenses to photo¬ ries_ 4 graph i c equipment 4. Classification and tolerances, (PH3.10)_ 42 Acme threads_ 4 4. Attachment threads for lens 5. Limits of size, Acme threads, 6 accessories (PH3.12)_ 42 6. Thread designations_ 7 5. Shutter cable release tip and 7. Gages for Acme threads_ 10 socket with taper (Euro¬ (a) Gage tolerances_ 10 pean) thread (PH3.23)_ 45 (b) Gages for external 6. Shutter cable release tip threads_ 10 and socket with straight (c) Gages for internal (American) thread threads_ 17 (PH3.24)_ 45 (d) Concentricity_ 18 Section XIX. Miscellaneous threads_ 45 Section XIII. Stub Acme threads_ 18 1. 60° stub threads_ 45 1. General and historical_ 18 2. Modified square threads_ 45 2. Specifications for Stub Acme 3. Threads for dairy sanitary form of thread_ 18 fittings_ 46 3. Standard Stub Acme thread 4. Glass bottle and jar threads. 46 series_ 19 4. Classification and tolerances, Appendix 10. Wrench openings_ 47 standard Stub Acme threads_ 19 Appendix 11. Class 5 interference-fit threads, 5. Limits of size, standard Stub Trial American Standard_ 48 Acme threads_ 20 1. Introduction_ 48 6. Thread designations_ 21 2. Scope_ 48 7. Alternative Stub Acme 3. Design and application data_ 48 threads_ 22 4. Tables of dimensions, torques, 8. G a g e s f o r Stub Acme and interferences_ 52 threads_ 25 (a) Gage tolerances_ 25 5. Extension of the standard_ 52 (b) Gages for external threads_ 26 Appendix 12. The tightening of threaded fasteners (c) Gages for internal to proper