4-2M_Edtn_2005.pdf

AN AMERICAN NATIO NAL STANDAR DMetric Hex Nuts,Style 2ASME B18.2.4.2M-2005Revision of ASME B18.2.4.2M-1979(R1995)Copyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.ASME B18.2.4.2M-2005Revision of ASME B18.2.4.2M-1979(R1995)Metric Hex Nuts,Style 2Three Park Avenue New York,NY 10016AN AMERICAN NATIONAL STANDARDCopyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.Date of Issuance:October 7,2005This Standard will be revised when the Society approves the issuance of a new edition.There will beno addenda issued to this edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Stan-dard.Interpretations are published on the ASME Web site under the Committee Pages athttp:/www.asme.org/codes/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 National Stan-dards.The Standards Committee that approved the code or standard was balanced to assure that individuals from com-petent and concerned interests have had an opportunity to participate.The proposed code or standard was made avail-able for public review and comment that 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 itemsmentioned in this document,and does not undertake to insure anyone utilizing a standard against liability for infringe-ment of any applicable letters patent,nor assumes any such liability.Users of a code or standard are expressly advisedthat determination of the validity of any such patent rights,and the risk of infringement of such rights,is entirely theirown responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted as gov-ernment 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 2005 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.Copyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.CONTENTSForeword.ivCommittee Roster .vCorrespondence With the B18 Committee .vi1Scope.12Comparison with ISO Standards.13Referenced Standards .14Terminology.15Dimensions .16Width Across Flats .37Thickness.38Tops and Bearing Surface.39Corner Fill .310True Position of Hexagon to the Tapped Hole.311Countersink .312Threads .313Material and Mechanical Properties.314Finish.315Identification Symbols .316Inspection and Quality Assurance.417Dimensional Conformance .418Designation .419Options .420Workmanship.4Table1Dimensions of Hex Nuts,Style 2 .2iiiCopyrighted material licensed to Stanford University by Thomson Scientific(),downloaded on Oct-05-2010 by Stanford University User.No further reproduction or distribution is permitted.Uncontrolled when printed.FOREWORDAmerican National Standards Committee B18 for the standardization of bolts,screws,nuts,riv-ets,and similar fasteners was organized in March 1922 as Sectional Committee B18 under theaegis of the American Engineering Standard Committee(later the American Standards Associa-tion,then the United States of America Standards Institute,and,as of October 6,1969,the Amer-ican National Standards Institute,Inc.),with the Society of Automotive Engineers and the Amer-ican Society of Mechanical Engineers as joint sponsors.Subcommittee 2 was subsequentlyestablished and charged with the responsibility for technical content of standards covering wrenchhead bolts and nuts.At its meeting on December 4,1974,Committee B18 authorized preparation of a series of stan-dards for metric fasteners.Subcommittee 2 was assigned responsibility for developing standardsfor metric hex bolts,screws,and nuts.At a meeting on September 22,1976,Subcommittee 2 organized the contents of a standard cov-ering six different styles of hex nuts.Actual drafting was postponed until ISO/TC2