ASME_B18.2.4.1M-2002.pdf

AN AMERICAN NA TIONALST ANDARDMETRIC HEX NUTS,STYLE 1ASME B18.2.4.1M-2002Revision of ANSI B18.2.4.1M-1979(R1995)Date of Issuance:April 1,2002This Standard will be revised when the Society approves the issuance of anew edition.There will be no addenda issued to this edition.ASME will issue written replies to inquiries concerning interpretation oftechnical aspects of this Standard.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 forAmerican National Standards.The Standards Committee that approved the code or standardwas balanced to assure that individuals from competent and concerned interests have had anopportunity to participate.The proposed code or standard was made available for public reviewand 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 inconnection withany itemsmentioned inthis document,and doesnot undertaketo insureanyoneutilizing a standard against liability for infringement of any applicable letters patent,nor assumeany such liability.Users of a code or standard are expressly advised that determination of thevalidity 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 tobe interpreted as government or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued inaccordance with the established ASME procedures and policies,which precludes the issuanceof 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 2002 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll Rights ReservedPrinted in U.S.A.CONTENTSForeword.vCommittee Roster.viCorrespondence With the B18 Committee.viii1General.11.11Scope.2Comparison With ISO Standards.13References.14Terminology.25Dimensions.26Width Across Flats.27Thickness.28Tops and Bearing Surfaces.29Corner Fill.210True Position of Hexagon to the Tapped Hole.211Countersink.212Threads.212.12Thread Series and Tolerance Class.12.24Thread Gaging.12.34Overtapped Threads.13Material and Mechanical Properties.413.14Steel.13.24Corrosion-Resistant Steels.13.34Nonferrous Metal.14Finish.415Identification Symbols.415.14Carbon and Alloy Steel Nuts.15.24Stainless Steel Nuts.15.34Nonferrous Nuts.16Inspection and Quality Assurance.4iii17Dimensional Conformance.418Designation.419Options.520Workmanship.5Table1Dimensions of Hex Nuts,Style 1.3ivFOREWORDAmerican National Standards Committee B18 for the standardization of bolts,screws,nuts,rivets,and similar fasteners was organized in March 1922 as Sectional CommitteeB18 under the aegis of the American Engineering Standards Committee(later the AmericanStandards Association,then the United States of America Standards Institute and,as ofOctober 6,1969,the American National Standards Institute,Inc.),with the Society ofAutomotive Engineers and the American Society of Mechancial Engineers as joint sponsors.Subcommittee 2 was subsequently established and charged with the responsibility for technicalcontent of standards covering wrench head bolts and nuts.At its meeting on December 4,1974,Committee B18 authorized preparation of a seriesof standards for metric fasteners.Sucommittee 2 was assigned responsibility for developingstandards for metric hex bolts,screws,and nuts.At a meeting on September 22,1976,Subcommittee 2 organized the contents of astandard covering six different styles of hex nuts.Actual drafting was postponed until ISO/TC2 could reach final decisions relating to basic dimensions and characteristics of hexbolts,screws,and nuts.At ISO/TC2 meetings held in April 1977,final actions were taken;Committee B18 affirmed the TC2 decisions at a meeting on June 29,1977;and draftingof this Standard was started.In February 1978,Committee B18 established a cooperative program with the Departmentof Defense to draft American National Standards for metric fasteners in such a way thatthey could be used directly by the government for procurement purposes.The Departmentof Defense requested that each of the six nut products be covered in separate standards,and Subcommittee 2 accepted this approach at its meeting on June 27,1978.The previous standard was approved by letter ballot of Committee B18 on July 2,1979,and was subsequently approved by the secretariats and submitted to the American NationalStandards Institute for designation as an American