1999_2017.pdf

REAFFIRMED 2017The American Society of Mechanical Engineers AN AMERICAN NATIONAL STANDARD CLEARANEE HOLES FOR BOLTS,SCREWS,AND STUDS ASME 61 8.2.8-1 MUM Date of Issuance:October 7,1999 This Standard will be revised when the Society approves the issuance of a new edition.There will be no addenda or written interpretations of the requirements of this Standard issued to this edition.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 representativek)or person(s)affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard.ASME accepts responsibilityforonly 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 0 1999 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed in U.S.A.During its December 3,1998 meeting,the ASME B18 Fastener Committee authorized preparation of a standard to establish clearance holes for inch-and metric-threaded fasteners.Some of the metric screw and bolt standards already had,as an appendix,the IS0 273 approved normal-,close-,and loose-clearance hole diameters.It was recognized that for inch standard fasteners there was no B18 standard size recommendation.A draft standard was prepared using common industry inch clearance values selected to follow the general metric design of three degrees of clearance.The recommendations are all tabulated as minimum holes and tolerance is recommended using IS0 273 tolerance classes.The Standard also includes values for fasteners in each system using the standard drill sizes from the other system of measurement.This Standard should provide consistent application design information for the fasteners and can be a step toward rationalization of the tooling for fastener assembly operations.Metric standards need not include the appended information in each threaded fastener standard and inch-threaded fastener standards will have standardized clearance hole recommendations.ASME B 18.2.8-1999 was approved by the American National Standards Institute(ANSI)on August 19,1999.111 ASME B18 STANDARDS COMMllTEE Standardization of Bolts,Nuts,Rivets,Screws,Washers,and Similar Fasteners(The following is the roster of the Committee at the time of approval of this Standard.)OFFICERS D.A.Clever,Chair R.D.Strong,Vice Chair S.W.Vass.Vice Chair R.L.Crane,Secretary COMMITTEE PERSONNEL J.C.Akins,Safety Socket Screw Corp.J.Altman,Rotor Clip Co.J.B.Belford,Lawson Products,Inc.D.Broomfield,Illinois Tool Works,Inc.J.A.Buda,SPS Technologies D.A.Clever,Deere and Co.T.Collier,Cam-Tech Industries,Inc.R.L.Crane,The American Society of Mechanical Engineers A.C.DiCola,Wrought Washer Co.A.Dinh,Defense Industrial Supply Center W.D.Downing,Consultant B.A.Dusina,Federal Screw Works D.S.George,Ford Motor Co.J.Greenslade,Greenslade and Co.6.Hasiuk,Defense Industrial Supply Center A.Herskovitz,U.S.Army ARDEC A.C.Hood,ACH Technologies J.Hubbard,Rockford Fastener,Inc.F.W.Kern,The Society of Automotive Engineers J.F.Koehl,Spirol International Corp.W.H.Kopke,ITW Shakeproof Assembly Co.J.G.Langenstein,Consultant M.Levinson,ITW Shakeproof Assembly Co.L.L.Lord,Caterpillar,Inc.A.D.McCrindle,Genfast Manufacturing Co.K.E.McCullough,Consultant R.F.Novotny,Textron M.D.Prasad,General Motors Corp.S.Savoji,I T W Medalist W.Schevey,BGM Fastener Co.,Inc.R.D.Strong,General Motors Corp.J.F.Sullivan,National Fasteners Distribution Association R.L.Tennis,Caterpillar,Inc.S.W.Vass,Industrial Fasteners Institute C.B.Wackrow,MNP Corp.R.G.Weber,Fairfield University W.K.