2009_2016.pdf

AN AMERICAN NATIO NAL STANDARD ASME B18.21.1-2009(Revision and consolidation of ASME B18.21.1 and ASME B18.22.1)Washers:Helical Spring-Lock,Tooth Lock,and Plain Washers(Inch Series)REAFFIRMED 2016Intentionally left blank ASME B18.21.1-2009(Revision and consolidation of ASME B18.21.1 and ASME B18.22.1)Washers:HelicalSpring-Lock,ToothLock,and PlainWashers(Inch Series)AN AMERICAN NATIONAL STANDARDDate of Issuance:January 22,2010This Standard will be revised when the Society approves the issuance of a new edition.There willbe no addenda issued to this edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of thisStandard.Periodically certain actions of the ASME B18 Committee may be published as Cases.Casesand interpretations are published on the ASME Web site under the Committee Pages athttp:/cstools.asme.org as they are issued.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 NationalStandards.The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate.The proposed code or standard was madeavailable forpublic review andcomment thatprovides an opportunityfor additional publicinput 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 anyitems mentioned in this document,and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent,nor assumes any such liability.Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights,and the risk of infringement of such rights,isentirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies,which precludes the issuance of interpretations by individuals.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 EngineersThree Park Avenue,New York,NY 10016-5990Copyright 2010 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword.ivCommittee Roster.viiCorrespondence With the B18 Committee.viii1General Data Related to All Washers.12General Data for Helical Spring-Lock Washers.23General Data for Tooth-Lock Washers.84General Data for Plain Washers(Flat and Fender).14Figures1Verifying Minimum Bearing Width.72Washer Twist Test.83Tooth Lock Washers.8Tables1Dimensions of Regular Helical Spring-Lock Washers.32Dimensions of Heavy Helical Spring-Lock Washers.43Dimensions of Extra-Duty Helical Spring-Lock Washers.54Dimensions of High-Collar Helical Spring-Lock Washers.65Decarburization Limits.66Dimensions of Internal Tooth-Lock Washers.97Dimensions of Heavy Internal Tooth-Lock Washers.108Dimensions of External Tooth-Lock Washers.119Dimensions of Countersunk External Tooth-Lock Washers.1210Dimensions of Internal/External Tooth-Lock Washers.1311Dimensions of Preferred Sizes of Type A Plain Washers.1512Dimensions of Type B Plain Washers.1713Fender Washers.20iiiFOREWORDIn response to the request of the U.S.War Department the American National StandardsCommittee B27,for the standardization of plain and lock washers was organized between August1925 and March 1926 as Sectional Committee B27 under the aegis of the American StandardsAssociation(later the American Engineering Standards,then The United States of AmericaStandards Institute,the American National Standards Institute and in subsequent years,thecommittee came under the sole sponsorship of the American Society of Mechanical Engineers(ASME).In May 1928,the B27 Committee established two subcommittees to carry on developmentwork,Subcommittee 1 on plain washers and Subcommittee 2 on lock washers.Subcommittee 2 circulated a tentative standard for helical spring-lock washers for industrycomment in November 1931,but failed to achieve acceptanceand committee activity was dormantfor some years.In 1940 the Subcommittee 2 project was reactivated and proceeded to draft aproposalcovering threeseries ofhelicalspring-lock washersdesignated light,medium,and heavy.In 1943 this proposal was amended to include the extra-heavy series washers and followingapproval by the B27 Committee and sponsor organizations it was accepted as an AmericanStandard under the designation ASA B27.1-1944.Subcomm