1997_2014.pdf

Intentionally left blank The American Society of Mechanical Engineers AN AMERICAN NATIONAL STANDARD ASME BI.5-1997(Revision of ASME/ANSI BI.5-1988)Date of Issuance:December 6,1999 The 1997 edition of this Standard is being issued with an automatic addenda subscription service.The use of an addenda allows revisions made in response to public review comments or committee actions to be published as necessary.The next edition of this Standard is scheduled for publication in 2002.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American National Standards.The Standards Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate.The proposed code or standard was made available for public review and comment which provides an opportunity for additional public input from industry,academia,regulatory agencies,and the public-at-large.ASME does not approve,rate,or endorse any item,construction,proprietary device,or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document,and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent,nor assume any such liability.Users of a code or standard are expressly advised that determination of the validity of any such patent rights,and the risk of infringement of such rights,is entirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations issued in accordance with governing ASME procedures and policies which preclude the issuance of interpretations by individual volunteers.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical Engineers Three Park Avenue,New York,NY 10016-5990 Copyright 1999 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A.FOREWORD When created prior to 1895,Acme screw threads were intended to replace square threads and a variety of threads of other forms used chiefly for the purpose of traversing motion on machines,tools,etc.Acme screw threads are now extensively used for a variety of purposes.Long-length Acme threads are used for controlled movements on machine tools,testing machines,jacks,aircraft flaps,and conveyors.Short-length threads are used on valve stems,hose connectors,bonnets on pressure cylinders,steering mechanisms,and camera lens movement.The Standards Committee on the Standardization and Unification of Screw Threads,B 1,was organized in June 1921,with the Society of Automotive Engineers and the American Society of Mechanical Engineers as joint sponsors under the procedure of the American Standards Association(ASA),now the American National Standards Institute(ANSI).This Committee was reorganized in May 1929,and its work was divided among five Subcommittees as follows No.I on Scope and Arrangement of American Standard;No.2 on Terminology and Form of Thread,Except Gages;No.3 on Special Threads and Twelve Pitch Series,Except Gages;No.4 on Acme Threads,Except Gages;and No.5 on Screw Thread Gages.National standardization of Acme screw threads in the United States was begun in 1932 when Subcommittee No.4 on Acme Threads of Standards Committee B I held its first meeting in New York.A report was presented on the types of Acme threads and the range of sizes and pitches in use in this country.It was prepared by C.W.Bettcher with the assistance of F.L.Woodcock.This report developed into a draft standard and was finally approved as an American Standard with the designation ASA B1.3-1941.It contained a section of introductory notes,and tables covering general purpose screws and general purpose nuts,basic dimensions of general purpose Acme threads with special and standard pitches,basic dimensions of 29 deg stub thread,measurements over three wires for Acme threads,basic dimensions of 60 deg stub thread,and basic proportions for modified square thread.In December 1942,to meet the war emergency,the National Aircraft Standards Committee of the Aeronautical Chamber of Commerce requested the ASA to consider the setting up of an American War Standard for special Acme screw threads for use in aircraft construction.Recognizing the vital importance of aircraft production to the war effort,the ASA initiated this project at once and organized a Special Committee to develop the Standard.Drafts of this proposed American War Standard were submitted,first on behalf of the National Aircraft Standards Committee and later b