1967_2009.pdf

U S A S T A N D A R D Preferred Limits and Fits for Cylindrical Parts USAS B4.1-1967 (R1974)Note For soft conversion of nominal dimensions and limits given in this standard,1 inch=25.4 mm.For explanation of conversion techniques see American National Standard 2210.1-1972,Metric Practice Guide.REAFFIRMED 1999 FOR CURRENT COMMllTEE PERSONNEL PLEASE SEE ASME MANUAL AS-11 sponmr The American Society o f Mechanical Engineers T H E A M E R I C A N S O C I E T Y O F M E C H A N I C A L E N G I N E E R S United Engineering Center 345 East 47th Street New York,N.Y.10017 REAFFIRMED 2009FOR CURRENT COMMITTEE PERSONNELPLEASE E-MAIL CSasme.orgANSI 84.1-1967 4 January 1972 ACCEPTANCE NOTICE The above Industry Standardization Document was adopted on 4 January 1972 and is approved for use by the DoD.The indicated industry groups have furnished the clearances required by exist-ing regulations.Copies of the document are stocked by Do0 Single Stock Point,U.S.Naval Publi-cations and Forms Center,Philadelphia,Pennsylvania 19120,for issue to DoD activities only.Title of Document:Preferred Limits and Fits for Cylindrical Parts Date of Specific Issue Adopted:18 September 1967-Plus Errata Releasing Industry Group:The American Society of Mechanical Engineers Custodians:Army-MU Navy-SH Air Force-70 Military Coordinating Activity:Air Force-70 Project No.MISC-0596 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 MECHASICAL ENGINEERS Copyrghr.a,1367.by Prlnred In U.S.A.Foreword T HIS standard represents the latest result of vork which began with the organization of Sec-tional Committee B4 in June 1920 under the name“Sectional Committee on the Standardiza-tion of Plain Limit Gages for General Engineering Work.”This original committee produced American Standard ASA B4a-1925,“Tolerances,Allowances and Gages for Metal Fits,”which was used in varying degree for many years.In December 1930,Sectional Committee 64 was reorganized and the name changed to the present form,“Sectional Committee on the Standardization of Allowances and Tolerances for Cylindrical Parts and Limit Gages.”The change in name indicated a significant shift to a more definite and somewhat more restricted mission for the committee.During the years of World War I1 an ASA War Committee formed in 1943 worked on the proj-ect but produced no completed results,and the activity was turned back to Sectional Committee B4.After the war the subject was discussed at the Canadian Conference on the Unification of Engineering Standards held in Ottawa in 1945,attended by delegates from Great Britain,Canada,and the United States,and again at another joint meeting in New York later in the same year.These meetings are significant because since 1945 work in this project has been strongly in-fluenced by these and similar ABC conferences.Proper evaluation of the present standard will depend upon an appreciation of the important effects of progress towards agreement on uni-fication of standards between the ABC countries.The result of the activities immediately following World War 11 was.4merican Standard“Limits and Fits for Engineerirg and Manufacturing (Part I),ASA B4.1-1947.”In the preface to that document it was stated that the ABC meetings resulted in agreement on five basc principles,and since the first four of these principles,with certain minor and obvious variations,apply to this present standard,it is considered worth while to repeat them here.First,there must be a common language (definitions)through which analyses may be recorded and conveyed.Second,a table of preferred basic sizes helps in reducing the number of different diameters commonly used in a given size range.Third,preferred tolerances and allowances are a logical comple-ment to preferred sizes and should aid the designer in se!ecting standard tolerances.Fourth,uniformity of method of applying tolerances is essential.Additional ABC conferences were held in New York in June 1952 and February 1953.Delega-tions from Sectional Committee B4 were active in these conferences,which resulted in a draft proposal for an ABC system of Limits and Fits,published as ASA 84/30.The Sectional Com-mittee B4 delegates to these conferences voted to recommend approval of the ABC proposals as the basis for an American standard if and when such a standard were developed.Since the publication of this standard there has been additional discussions at ABC con-ferences held in Ottawa in June 1960 and at Arden House,New York,in September 1962.There has been an expansion of definitions under ASA B1.7,and they are reflected in the revision.The revised proposal was submitted to the sponsor organization and to the USA Standards Institute (formerly American Standards Association)for final approval as a USA Standard.This approval was granted on August 3,1966.This revision,however,was never published as it was noted that other rhanges