Asme b18 2 3 1m 1999 (american society of mechanical engineers)

COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services The American Society of Mechanical Engineers A N A M E R I C A N A T I O N A S L T A N D A R D METRIC HEX CAP SCREWS ASME B m L m l M-If i l [Revision 01 ANSI I 8.2.3.1 M-1979 (RlNfl5)] COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services Date of Issuance: December 31, 1999 The 1998 edition of this Standard is being issued with a n automatic addenda subscription service The use of an addenda allows revisions made in response to public review comments or committee actions to be published as necessary The next edition of this Standard is scheduled for publication in 2004 ASME is the registered trademarkof 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 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 withrespect 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 representativeb) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard ASME accepts responsibility for only those interpretations of this document issued in accordance with the established ASME 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 permissionof the publisher The American Society of Mechanical Engineers Three Park Avenue, New York, NY 10016-5990 Copyright Q 1999 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All Rights Reserved Printed i n U.S.A COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services FOREWORD AmericanNational Standards Committee B 18 for the standardization of bolts, screws, nuts, rivets, and similar fasteners was organized in Marchof1922, as Sectional Committee B18 under the aegis of the American Engineering Standards Committee (later the American Standards Association,thentheUnited States of America Standards Institute and, as of October , 1969,theAmericanNational Standards Institute, Inc.), withtheSociety of Automotive Engineers and the American Society of Mechanical Engineers as joint sponsors Subcommittee was subsequently established and charged with the responsibility for technical content of standards covering wrenchheadboltsand nuts At itsmeetingonDecember 4, 1974,Committee B18 authorized preparation of a series of standards for metric fasteners Subcommittee was assigned responsibility for developing standards for metrichex bolts, screws, and nuts On September 22, 1976, Subcommittee organizedthe contents of a standard covering eight different hexhead screw andbolt products Actual drafting waspostponed until ISO/TC2 could reachfinal decisions relating tothebasic dimensions and characteristics of hex bolts, screws, and nuts At ISO/TC2 meetings held in April of 1977,final actions were taken Committee B18 affirmed the TC2 decisions at a meeting on June29,1977,and drafting of this Standard was started Committee B 18, in February of 1978, established a cooperative program with the Department of Defenseto draft AmericanNational Standards for metric fasteners in such a way that they could beuseddirectly by the Government for procurement purposes The Department of Defenserequestedthateach of the eight products be covered in separate standards, and Subcommittee acceptedthisapproachatitsmeeting on June 27, 1978 This Standardwasapproved by letter ballot of Committee B 18 on September 15, 1978, andwassubsequentlyapproved by the secretariat and submitted totheAmericanNational Standards Institute for designation as an AmericanNational Standard This was granted on April26,1979 B 18.2.3.1M was subsequently reaffirmed in 1989andagain in 1995 In 1997, a revisionwasintiatedto try andalignthis Standard withits I S counterpart A letter ballot, which closed in November of 1998, was not approved and in early December of 1998, Subcommittee metto resolve the negatives Aspart of the resolution of these negatives, it was agreedtoinclude in thisForeword a summary ofkey changes to this Standard The following isthat summary: It wasmade clear in para 1.4.1 that all dimensions in this Standard applybeforeany coating hasbeen applied Thewasher face diameter isnow to be inspected a 0.1 mm above thebearingplaneand notat midthickness as it was previously The length of point was redefined, including a new method for checking an increased maximumpointlength defined in para.2.5and Table Screw straightness, which formerly was checked with a sleeve gage, is now checked with a rail gage as established in para 2.6 The position of body-to-thread, which is checkedwith a sleeve gage, now applies onlytocutthreads as established in para 2.7.6, with new tolerance zonevaluesshown in Table Grip lengthandbodylengthwererevisedto correspond to the IS0 standard This results in the following standard diameterllength combinations being fully threaded and not partially threaded as theywere previously: 111 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services M8 x 35 MI0 x 40 MI2 x 45 MI4 x 50 MI4 x 55 MI6 x 55 MI6 x 60 M20 x 65 M20 M24 M30 M36 M36 M36 M42 M42 x 70 x 80 x 100 x 110 x 120 x 130 x 150 x 140 M42 M42 M48 M48 M56 M56 M64 M64 x 130 x 120 x 160 x 150 x x x x 200 180 240 220 M64 M72 M72 M72 M80 M80 M80 M90 x M90 200 x M90 260 x M90 240 x 220 x 280 x 260 x 240 x 320 x 300 x 280 x 260 MI00 x 340 MI00 x 320 MI00 x 300 MI00 x 280 For screws threaded full length,the grip lengthwasincreased approximately to times pitchfrom 2.5 timespitch (see Table 6) The previous requirement for a controlled root radius in the runout section of the thread on products of Property Class 10.9 or greater was replaced by a requirement for a rounded root contour included in para 2.7.5 Quality assurance and dimensional conformance have beenspecifiedandincluded in paras 2.13 and 2.14, respectively Appendix IV provides a detailed comparison of product characteristics in this Standard as compared to those of KO Users of this Standard are urgedtoreviewits contents carefully so thatno confusion exists withthe provisions of the previous editions of this Standard This revisionwasapproved as an American National Standard onMay 10, 1999 iv COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME B18 STANDARDS COMMITTEE Standardization of Bolts, Nuts, Rivets, Screws, Washers, and Similar Fasteners (The following is the rosterof the Committee at the timeof 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 H Slass, Alternate, Rotor Clip 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, Emhart Heli-Coil B A Dusina, Federal Screw Works D S George, Ford Motor Co D L Drobnich, Alternate, Ford Motor Co J Greenslade, Greenslade & Co B Hasiuk, Defense Industrial Supply Center A Herskovitz, Consultant A C Hood, ACH Technologies J Hubbard, Rockford Fastener, Inc F W Kern, Consultant J F Koehl, Spirol International Corp W H Kopke, ITW Shakeproof Assembly Corp J G Langenstein, Consultant M Levinson, ITW Shakeproof L L Lord, Caterpillar, Inc A D McCrindle, Genfast Manufacturing Co K E McCullough, Consultant R F Novotny, Camcar Decorah Operations M Prasad, General Motors Corp 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 School of Engineering COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services W K Wilcox, Naval Sea Systems Command C J Wilson, Industrial Fasteners Institute SUBCOMMITTEE - EXTERNAL DRIVE FASTENERS S.W V a s , Chair, Lake Erie Screw Corp R L Crane, Secretary, The American Society of Mechanical Engineers D Broomfield, Illinois Tool Works, Inc R M Byrne, Trade Assoc Management, Inc D A Clever, Deere and Co A P Cockman, Ford Motor Co R J Corbett, Huck International Industrial Fasteners A Dinh, Defense Industrial Supply Center D S George, Ford Motor Co J Greenslade, Greenslade & Co A Herskovitz, Consultant M W Hc!ubecki, Electric Boat Corp J Hubbard, Rockford Fastener, Inc D F Kattler, SPS Technologies L L Lord, Caterpillar, Inc A D McCrindle, Genfast Mannufacturing Co K E McCullough Consultant J A Schlink, Caterpillar, Inc R L Tennis, Caterpillar, Inc C B Wackrow, MNP Corp W K Wilcox, Naval Sea System Command C J Wilson, Industrial Fasteners Institute vi COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services CORRESPONDENCE WITH THE 618 COMMITTEE General ASME Standards are developed and maintained with the intent to represent the consensus of concerned interests As such, users of this Standard may interact with the Committee by requesting interpretations, proposing revisions, and attending Committee meetings Correspondence should be addressed to: Secretary, B 18 Main Committee The American Society of Mechanical Engineers Three ParkAvenue New York, NY 10016-5990 Proposing Revisions Revisions are made periodically tothe Standard to incorporate changes that appear necessary or desirable, as demonstrated by the experience gained from the application of the Standard Approved revisions will bepublished periodically The Committee welcomes proposals for revisions to this Standard Such proposals should be as specific as possible, citing theparagraph number(s), theproposedwording,and a detaileddescription of thereasons for theproposal, including any pertinent documentation Interpretations Upon request,the B 18 Committee will render an interpretation of any requirement of the Standard Interpretations canonlyberendered in response to a written requestsenttothe Secretary of the B18 Main Committee The request for interpretation should be clear and unambiguous It is further recommended thatthe inquirer submit hisher request in the following format: Subject: Edition: Question: Cite the applicable paragraph number(s) and the topic the of inquiry the interpretation Cite the applicable edition of the Standard for which isbeing requested Phrase the question as a request for an interpretation of a specific requirement suitable for general understanding and use, notas a request for an approval of a proprietary design or situation The inquirer may also include anyplans or drawings, which are necessaryto explain the question; however, they should not contain proprietarynames or information Requeststhatarenot in thisformat maybe rewritten in the appropriate format by the Committee prior to being answered, whichmay inadvertently change theintent ofthe original request ASME procedures provide for reconsideration of any interpretation when or if additional informationthatmight affect an interpretation is available Further, persons aggrieved by aninterpretation may appealtothe cognizant ASME Committee or Subcommittee ASME does not “approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity Atfending Cornmiltee Meetings The B I8 Main Committee regularly holds meetings, which are opentothe public Persons wishingtoattendany meeting should contact the Secretary ofthe B18 Main Committee vii COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services Foreword Standards Committee Roster Correspondence With the B18 Committee 111 V vii Introductory Notes General Data Figures Washer Face Detail Fillet Detail for Short Screws Fillet Detail for Long Screws Tables Tolerance Zones Dimensions of Underhead Fillets Dimensions of Hex Cap Screws Thread Lengths Dimensions of Points Maximum Grip GagingLengths Lg andMinimumBodyLengths L Thread Lengths Nonmandatory Appendices A Screw Straightness Gage and Gaging Procedure B Body Position Gages and Gaging Procedures C Recommended Clearance Holes for Screws D Comparison With I S Standards ix COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services 5 8 10 12 13 15 17 19 ASME B18.2.3.1M-1999 METRIC HEX CAP SCREWS 1INTRODUCTORYNOTES which are not in IS0 4014 or IS0 4017 This Standard specifies some requirements that are notincluded in IS0 4014 or IS0 4017 Dimensional requirements shown inbold type withinthe text and where noted within tables differ from, orare in addition to, IS0 4014 and/or IS0 4017, or, for sizes over M64, other relevant nonproduct IS0 standards The technical differences between this Standard and the IS0 standards are summarized in Appendix IV 1.1 Scope 1.1.1 This Standard covers the complete general and dimensional data for metric series hex cap screws recognized asAmericanNational Standard 1.1.2 The inclusion of dimensional data in this Standard is notintended to implythat all of the sizes in conjunction with the various options described herein are stock items Consumers should consult with suppliers concerning lists of stockproduction hex cap screws 1.2.2 At its meeting in Varna in May of 1977, ISO/ TC2 studied several technicalreports analyzing design considerations influencing determination of thebest series of width across flats for hexagonbolts, screws, and nuts A primary technical objective was to achieve a logical ratio between the head or nut bearing surface area (which determines the magnitude of the compressive stress onthebolted members) andthe tensile stress area of thescrewthread (which governs the clamping force that can be developed by tightening the fastener) MI0 screws with 15 mm width across flats are currentlybeingproducedandused in the U.S and many other countries of the world This size, however, isnotan IS0 standard Unless M I O screws with 15 mm width across flats are specifically ordered, M I screws with 16 mm width across flats shall be furnished 1.2 Comparison With IS0 Standards 1.2.1 Hex cap screws, sizes M5 to M U , as presented in this Standard are harmonizedtothe extent possible with IS0 4014 or, for short screws threaded full length, with IS0 4017 Dimensional differences betweenthis Standard and IS0 4014 or IS0 4017 are few, relatively minor, andnone will affect thefunctionalinterchangeability of screws manufacturedtotherequirements of either The following functional characteristics of screws, sizes M5 through MI4 with nominallengths times diameter through I O times diameter, sizes MI6 through M24 with nominallengths times diameter through 150 mm, and sizes M30 through M64 withnominal lengths times diameter and longer, are in agreement between this Standard and I S 4014 or IS0 4017, as applicable: ( a ) nominal diameters andthread pitches, (6) body diameters, (c) widths across flatsand comers (see para 1.2.5), (d) nominalhead heights, ( e ) nominallengthsandthread lengths, and (f) thread dimensions This Standard omits sizes MI 6-M4, MI 8, M22, M21, M33,M39,M45,M52, and M60, whichare included in IS0 4014 and I S 4017 This Standard includes sizes MI0 x I with 15 mm width across flats, M72 x 6, M80 x 6, M90 x 6, and MlOO x 6, 1.2.3 Letter symbols designating dimensional characteristics are in accord with I S 225, IS0 4014, and I S 4017, except where capitals have been used instead of thelower case letters used in the IS0 standards 1.3 Terminology For definitions of terms relating to fasteners or component features thereof used in this Standard, referto ASME B18.12 1.4 Dimensions 1.4.1 All dimensions in this Standard are in millimeters (mm) and apply beforeany coating, unless stated otherwise I COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services m and Thread Pitch, Nominal Diameter Screw ~ 1.75 2 2.5 3.5 4.5 5.5 M12 x MI4 x M16 x M20 x M24 x M30 x M36 x M42 x M48 x M56 x M x 0.8 M6x M x 1.125 M I x 1.5 (7) M10 x 1.5 (7) 30.00 36.00 42.00 48.00 56.00 29.67 35.61 41.38 47.38 55.26 (8) (8) 12.00 14.00 16.00 20.00 24.00 5.00 6.00 8.00 10.00 10.00 11.73 13.73 15.73 19.67 23.67 4.82 5.82 7.78 9.78 9.78 ~~~~ Body Diameter, 0, [Note (1I1 45.00 53.80 62.90 72.60 82.20 (8) (8) (8) 17.73 20.67 23.67 29.16 (8) 35.00 (8) 7.78 9.78 12.73 14.73 15.73 S 46.00 55.00 65.00 75.00 85.00 18.00 21.OO 24.00 30.00 36.00 8.00 10.00 13.00 15.00 16.00 50.85 60.79 71.71 (8) 82.76 (8) 93.71 (8) 20.03 23.35 26.75 32.95 (8) 39.55 (8) 8.79 11.05 14.38 16.64 17.77 6.17 ~ 53.12 63.51 75.06 86.60 98.15 20.78 24.25 27.71 34.64 41.57 9.24 11.55 15.01 5.50 17.32 18.48 17.92 21.62 25.03 28.93 33.80 7.24 8.51 9.68 12.12 14.46 3.35 3.85 5.10 6.17 19.48 23.38 26.97 31.07 36.20 7.76 9.09 10.32 12.88 15.44 6.63 6.63 3.65 4.15 Width Across Height Head Corners, E K [Note (211 [Note (311 DIMENSIONS OF HEX CAP SCREWS Width Across Flats, TABLE Property class and source identification to appear on top of head see para 2.10 NoteMax Min Max Min Max D Min Max Min COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services 13.1 15.8 18.2 21 o 24.5 5.2 6.2 7.0 8.8 10.5 2.4 2.8 3.7 4.5 4.5 ~~ (4)] Height, [Note K,, Min Wrenching 0.8 Optional Point Construction (see para 2.5) para 2.7.4 ~~ 0.4 0.4 0.5 0.5 0.5 0.3 0.3 0.4 0.4 0.4 0.2 0.2 0.3 0.3 0.3 ~ Min 0.8 0.8 1.0 1.0 1.0 0.6 0.6 0.8 0.8 0.5 0.5 0.6 0.6 0.6 ~~ Max Washer Face Thickness, C (511 (continued) 42.7 51.1 59.8 69.0 78.1 16.6 19.6 22.49 27.7 33.2 7.0 8.9 11.6 13.6 14.6 [Note (6)] Washer Face Diameter, D,, Min cn % I rn X c) c) 2 W W W T m, m N w COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services Max 64.00 72.00 80.00 90.00 100.00 Min 63.26 71.26 79.26 89.1 99.1 Body Diameter, 0, [Note (1I1 91.80 101.40 111.00 125.50 140.00 Min (8) (8) (8) (8) 18) S 95.00 105.00 115.00 130.00 145.00 Max Width Across Flats, 104.65 (8) 115.60 (8) 126.54 (8) 143.07 (8) 159.60 167.43 (81 Min 109.70 121.24 132.72 150.11 Max Width Across Corners, E [Note l2)l Max 41.32 46.45 51.58 57.75 63.90 Min 38.68 43.55 48.42 54.26 60.10 Head Height, K [Note (311 28.0 31.5 35.0 39.2 43.4 1.0 Wrenching Height, Kw, Min [Note ( 0.5 0.6 0.6 0.6 0.6 Min 1.2 (8) 1.2 (8) 1.2 (8) 1.2 (8) Max Washer Face Thickness, C [Note (511 87.2 96.3 105.4 119.2 133.0 Washer Face Diameter, D , Min [Note (611 GENERAL NOTES: (a) All sizes except the following are included in I S 4014 and IS0 4017: M10 x 1.5 with 15 m m WAF, and M72 thru M100 (b) M10 screws with 15 mm WAF are commonly produced in the USA and other countries The WAF for allMlO's should be specified NOTES: (1) For D,, see para 2.3 (2) For E, see paras 2.1.3 and 2.1.4 (3) For K, see para 2.1.2 For K, except M5 x 0.8 and M6 x 1, see para 1.2.1 (4) For K,, see paras 1.2.1 and 2.1.3 (5) For C,see para 2.1.6 For C,Min., see para 1.2.1 (6) For D, see para 2.1.6 For ,except M16 x 2, see para 1.2.1 (7) Unless M10 screws with 15 mrn width across flats are specifically ordered, M10 screws with 16 mm width across flats shall be furnished (see para 1.2.2) (8) See Appendix D, paras D4, D6, D7, D9, DlO, and D13 M64 x M72 x M80 x M90 x MlOO x Nominal Screw Diameter and Thread Pitch, D TABLE DIMENSIONS OF HEX CAP SCREWS (CONT'D) (n 33 Ln g rn I X E z I 33 rn METRIC HEX CAP SCREWS ASME 818.2.3.1M-1999 TABLE LENGTH TOLERANCES ~~ Nominal Length Over M12 18 60 50 60 k0.60 10 18 30 50 k0.60 60 80 100 120 140 150 180 250 315 400 Nominal Screw Diameter Thru M10 M5 M8 10 20.29 20.29 20.35 20.42 20.50 30 k0.60 80k1.50 100t1.75 120 140 150 180 250 315 400 500 ~~~~ k1.50 k1.75 k1.75 k2.00 22.00 22.00 22.30 22.60 22.85 23.15 ~~~ M6 MI4 >M24M16-M24 20.35 20.42 k0.50 20.60 20.29 k0.35 20.35 20.42 20.50 k0.50 k0.60 k0.29 20.35 20.42 20.50 20.60 k1.75 k2.00 22.00 22.00 22.30 22.60 22.85 23.15 21.75 21.75 22.00 22.00 22.00 22.30 22.60 k2.85 23.15 20.70 21.75 +2.00 k2.00 22.00 22.30 k2.60 22.85 23.15 20.42 20.60 k0.60 20.70 20.70 22.00 22.00 22.00 22.30 22.60 22.85 23.15 20.35 +0.42 20.50 20.60 20.70 20.70 20.80 22.00 22.00 22.30 t2.60 22.85 k3.15 t0.35 20.42 20.50 +0.60 ~0.70 20.70 20.80 k0.80 k2.00 k2.30 k2.60 k2.85 23.15 21.05 21.25 21.50 t1.50 21.75 21.75 r2.00 22.00 22.00 22.30 52.60 22.85 23.15 ~~ GENERAL NOTE: All tolerances are plus and minus shall be within thepositional tolerance zone diameter specified in Table I, with respect tothe axis of the thread, over a length equal to the nominal screw diameter fromthelast complete thread A gage and gaging procedurefor checking body.position isgiven in Appendix B TABLE DIMENSIONS OF POINTS Nominal Screw Diameter and Thread Pitch Point Radius,& Approx [Note (111 Point Length, U, Max [Note (211 M x 0.8 M6x M x 1.25 M10 x 1.5 7.0 8.4 11.2 14.0 1.60 2.00 2.50 3.00 M12 x MI4 x M16 x M20 5.00 x 1.75 2 2.5 16.8 19.6 22.4 28.0 3.50 4.00 4.00 M24 x 7.00 x M30 M36 x M42 x 3.5 4.5 33.6 42.0 50.4 58.8 6.00 M48 x M56 x M64 x M72 x 5.5 6 67.2 78.4 89.6 100.8 10.00 1.oo 12.00 12.00 112.0 126.0 140.0 12.00 12.00 12.00 M80 x M90 x M100 x 2.8 Screw Threads 2.8.1ThreadSeriesandTolerance Class Screw threadsshall be general purpose metricscrew threads with tolerance Class 6g conforming toASME B1.13M, unless otherwise specified by the purchaser For screws with additive finish, size limits for tolerance Class 6g applypriorto coating, andthethread after coating is subject to acceptance using a basic (tolerance position h) size GO thread gage andtolerance Class 6g threadgage for either minimum material, LO or NOT GO 8.00 9.00 2.8.2 Thread Gaging Unless otherwise specified, dimensional acceptability of screw threadsshall be based on System 21 of ASME B 1.3M 2.9 Materials and Mechanical Properties NOTES: (1) Re, approx., equals 1.4 times the nominal screw diameter, and agrees with I S 4753 (2) U,max., equals times the thread pitch 2.9.1 Steel Unless otherwise specified, steel screws shall conform to the requirements of ASTM F 568M or SAE JI 199 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME B18.2.3.1M-1999 METRIC HEX CAP SCREWS 2.13Inspection 2.9.2 Corrosion-Resistant Steels Unless otherwise specified, screws made of corrosion-resistant steels shall conform tothe requirements of ASTM F 738M Unless otherwise specified, acceptability of screws shall be determined in accordancewithASME B18.18.IM 2.9.3 Nonferrous Metals Unless otherwise specified, nonferrous screws shall conform tothe requirements ofASTM F 468M 2.14 Dimensional Conformance 2.14.1 Products shall conform to the specified dimensions Unless otherwise specified, the following provisions shall apply for inspection of dimensional characteristics The designated characteristics are defined within the following table and shall be inspected in accordance with ASMEB18.18.2Mtotheinspectionlevel shown 2.10 ldentification Symbols ldentification marking symbols shallbe on the top of screw headsandshall be raised or indentedatthe manufacturer’s option unless otherwise specified at the time of ordering Markings shallbe legible tothe unaided eye withthe exception of corrective lenses (a) When raised, markings shall projectnot less than 0.1 mm for M14 and smaller screws, and 0.3 mm for M16 and larger screws, above the surface of the head The total head height (head plus markings) shall not exceed the specified maximum head height plus 0.1 mm for M5 and M6 screws, 0.2 mm for M8 and M10 screws, 0.3 mm for M12 and M14 screws, and 0.4 mm for M16 and larger screws ( b ) Whenindented,the depth of themarkingshall not reduce theload carrying capability of the screw Characteristic Thread acceptability Head width across comers, E Grip length LR max Screw length .La Visual inspection inspection Level C C C C C NOTE: Visual inspection shall include property class marking, source marking fillet, and workmanship If verifiable in-process inspection is used, inspection sample sizes and reporting shall be i n accordance with the applicable ASME,ASTM, or SAE quality system consensus standard 2.10.1 Property Class Symbols Each screw shall be marked in accordance withthe requirements ofthe applicable specification for its chemical and mechanical requirements 2.14.2 For nondesignated dimensional characteristics, the provisions of ASME B 18.18.1M shall apply Should a nondesignated dimension be determined to be outside itsspecified limits, it shall be deemed conforming to this standard if theuser,who is the installer, accepts the dimension, based on fit, form, and function considerations 2.10.2 Source Symbols Each screwshall be markedtoidentify its source (manufacturer or private label distributor) 2.11 Finish 2.15Clearance Unless otherwise specified, screws shallbe supplied Holes The recommended sizes of clearance holes in material to be assembled usinghex cap screws are thenormal series given in Appendix C with a natural (as processed) finish,unplated or uncoated, in a clean condition andlightly oiled 2.16 Designation 2.12 Workmanship 2.16.1 Hex cap screws shall be designated by the following data, preferably in the sequence shown: product name,nominal diameter andthread pitch, nominal length, steel property class or material identification, and protective coating, if required For example: Screws shall be free from surface imperfections such as burrs, seams, laps, loose scale, or other irregularities that could affect serviceability When control of surface discontinuities is required, the purchaser shall specify conformance toASTM F 788E 788M or SAE J 1061 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services and Quality Assurance METRIC HEX CAP SCREWS ASME 818.2.3.1M-1999 TABLE MAXIMUM GRIP GAGING LENGTHS L, and MINIMUM BODY LENGTHS L, Nominal Diameter and Thread Pitch M x 0.8 Nominal L, Length, ax.Min.Max.Min.Max.Min L Max.Min.Max M8 x 1.25 M6 x Ls LP 1.2 (1) 10 2.4 1.5 (1) 2.4 12 3.0 16 2.4 3.0 20 2.4 3.0 25 9.0 3.0 7.0 12.0 30 10.0 14.0 12.0 17.0 35 15.0 19.0 75 18.0 17.0 22.0 4020.0 24.0 27.0 25.0 29.0 45 28.0 27.0 50 34.0 6.0 11.25 25.0 21.5 55 29.0 26.75 33.0 60 31.75 38.0 4210- -~_.37.0 65 70 80 , 90 100 110 120 130 140 150 160 180 200 220 240 260 280 300 ?E:: L, Lg ~ 32.0 M10 x 1.5 L* 1.9 (1) 4.0 4.0 4.0 4.0 4.0 20.0 r, LS * I I 16.5 21.75 M12 x 1.75 2.2 4.5 4.5 4.5 4.5 4.5 (1) 24.0 LS I L, I 2.6 (1) 2.6 (1) 5.3 5.3 5.3 5.3 5.3 .36.75 43.0 34.0 30.0 26.5 39.0 21 31.0 31.5 26.2535.0 2: ’i -L - 48.0 40.036.544.0 41.75 58.0 50.046.554.0 51.75 I ~~~~~ ~~~~ 60.0 56.5 70.0 66.5 ~~ 80.0 ! 90.0 Hex capscrew, M I x 1.5 x 50, Class 9.8, zincplatedper F 87 IM and ASTM B 633 Fe/Zn Type 11 ASTM Hexcapscrew, EXAMPLE: Hex cap screw, Alloy 651 X X 70 Class 10.9, Phosphate/OiL ASTM I 3.0 (1) 3.0 (1) (1) ;:; ::: I 6.0 6.0 6.0 21.25 26.0 16.0 31.25 26.0 41.25 51.25 61.25 56.0 71.25 76.0 81.25 36.0 46.0 56.0 66.0 76.0 86.0 90.0 100.0 j L2 and L , .o 36.0 46.0 66.0 E J values shall be EXAMPLE: M8 x 1.25 x 45 AI-70 ASTM F 738M 2.16.2 For a recommended part identification numbering (PIN) see system, ASME B 18.24.1 M6 x I x 35 silicon bronLe, ASTM F 468M 10 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services L* NOTE: I t is commonpractice in IS0 standardsto omit thread pitch from theproduct size designationupto M64 whenscrewthreads are the metric thread series (e,g,, M I O is M I O x 1.5) EXAMPLE: Hex cap Screw, MI6 F I 137 Grade I Lg GENERAL NOTES: (a) Diameter-length combinations between the thin stepped lines are recommended (b) Screws with lengths above the thick stepped line are threaded full length; see Table (c) For screws of larger sizes and/or with lengths longer than those below the lowest stepped line, computed from the formulas given in para 2.7 of General Data NOTE: (1) See Appendix D, para D16 EXAMPLE: M14 x .5 SCREWS METRIC HEX CAP ASME B18.2.3.1M-1999 TABLE MAXIMUM GRIP GAGING LENGTHS LE and MINIMUM BODY LENGTHS L, (CONT'D) ~~~ Nominal Diameter and Thread Pitch Max Nominal Length, Min Max L Min M20 x 2.5 M16 x L, % L, Max M30 x 3.5 M24 x L, Lg Min L* Max Min.Min Lg Max 10 12 16 20 3.0 (1) 25 30 3.0- (1, 3.8 (1) 6.0 13.8-.11!_ 35 9.0 6.0 7.5 10.5 -1 9.0 40 6.0 7.5 45 9.0 10.5 6.0 7.5 50 9.0 10.5 9.0 12.0 10.5 6.0 7.5 55 6.0 9.01 60 27.0 17.0 9.0 10.5 65 22.0 32.0 70 34.0 42.0 32.0 80 44.0 36.0 21.0 10.5 52.0 42.0 90 31.5 54.0 62.0 52.0 100 41.5 46.0 12.0 10.5 31.0 64.0 62.0 72.0 110 51.5 56.0 41.O 74.0 72.0 120 66.0 61.5 5112.0 O 36.5 54.0 82.0 78.0 130 86.0 76.0 65.5 40.5 70.0 12.0 58.0 55.0 88.0 140 96.0 86.0 75.5 80.0 65.0 68.056.0 15096.0 106.0 46.0 98.0 66.0 85.5 60.5 90.0 78.0 75.0 108.0 106.0 160 16.0 90.0 85.0 88.0 180 90.5 108.0 96.0 105.0 120.0 115.5 128.0 200 96.0 116.0110.5 128.0125.0.140.0 135.5148.0 220 103.0 123.0 117.5 135.0132.0 147.0 240 143.0 137.5 155.0 152.0 137.0 260 143.0 163.0 157.5 175.0 163.0 183.0 177.5 195.0 280 300 183.0 203.0 197.5 215.0 ~ ~ ~~ ~ ~ - L I I I 1 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services M36 x r, L, * 12.0 12.0 12.0 50.5 70.5 36.0 76.0 56.0 76.0 123.0 METRIC ASME 818.2.3.1M-1999 TABLE THREAD LENGTHS Length, Thread 9, Ref Length Nominal Screw Transition Screw Screw Diameter Screw Lengths, Screw Thread Lengths, Under Head, Lengths, and L, 125 Lengths, Length, Thread Pitch L, < 125 & S 200 L, > 200 Threaded Screws Unthreaded 1.2 1.5 1.9 2.2 45 2.6 50 10 12 16 20 24 25 30 40 2.4 3.0 4.0 4.5 5.3 10.0 10.0 12.5 15.0 17.5 28 32 40 3.0 3.0 3.8 28 32 40 60 65 80 90 110 6.0 6.0 7.5 9.0 10.5 140 160 180 220 260 12.0 13.5 15.0 16.5 18.0 280 300 340 360 18.0 18.0 18.0 18.0 35 37 41 45 49 M14 x M16 x M20 x M24 x M30 x 2 2.5 3.5 34 57 38 65 46 54 66 40 44 52 60 72 53 73 85 M36 x M42 x M48 x M56 x M64 x 4.5 5.5 97 109 121 137 153 20.0 22.5 25.0 84 96 108 27.5 .30.0 169 185 205 225 30.0 30.0 30.0 30.0 4.0 5.0 6.25 7.5 8.75 NOTE: (1) See Appendix D, para D16 12 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services L 10 12 16 20 24 X, Ref Under 22 24 28 32 36 Unthreaded Length Under Head, A, Max A, Max [Note (I)] 16 18 22 26 30 M72 x M80 x M90 x MlOO x Screw Lengths, L, M5 x 0.8 M6 x M x 1.25 M10 x 1.5 M12 x 1.75 Full Length Least At Under ASME 818.2.3.1M-1999 NONMANDATORY APPENDIX A SCREW STRAIGHTNESS GAGE AND GAGING PROCEDURE The conformance of screws to shank straightness or camber limitations, set forth in para 2.6, shall be checked by usingthe gage, illustrated in Fig A I , in accordance withthefollowingprocedure: Allowable total camber on the product to be inspected shallbe calculated in accordance with para 2.6 The total camber thus derived shall be added to the specified maximum body diameter and the movable rail of gage shallbe adjusted toprovide a parallel space between the rails equal to this distance by obtaining common readings onbothmicrometer heads The movablerail shall thenbelocked in place by tightening securing screws The product shall then be inserted between rails, and shallberotated byhand through full 360 deg Any interference occurring betweenthe product andthe gage that is sufficient to prevent rotation shall indicate excessive camber Reverse reading micrometer heads Securing screws Maximum body diameter plus allowable total camber FIG A1 TYPICAL STRAIGHTNESS GAGE 13 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME 818.2.3.1M-1999 NONMANDATORY APPENDIX B BODY POSITION GAGES AND GAGING PROCEDURES Gages that maybeusedfor checking position of the screw body with respect to the thread are illustrated below in Fig B I In the lower construction, GO threadring gage A is centered on sleeve B by means of thepositioning plug E, and is secured in position by attachment screws C The ring gage is set to the maximum pitch diameter of the screwthread, Class 6h For position of body-to-threadper para 2.7.6, gage length, Lh, is equaltothenominalscrew diameter, D, plusthetransitionthread length, X, i.e t Lh Diameter Oh,of the counterbore or hole in sleeve(s), equals the nomial screw diameter, D, plus the positional tolerance, T2 (see Table I), i.e The screw is screwed by hand into the GO thread gage for the full length of the thread Class 6h GO thread gage optional constructions Class 6h max PD thread + o.Oo0 Y D , -0.015 FIG B1 TYPICAL GAGE COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services = D+X ASME 818.2.3.1M-1999 NONMANDATORY APPENDIX C RECOMMENDED CLEARANCE HOLES FOR SCREWS The recommended sizes of clearance holes in material to be assembled using hex cap screws are thenormal series, given below in Table CI TABLE C1 CLEARANCE HOLES FOR SCREWS Clearance Hole Diameter, Dh [Note (111 Nominal Screw Diameter and Thread Pitch Normal Loose Clearance Close Preferred [Note (211 Clearance [Note (311 Clearance [Note (4)l 5.8 M x 0.8 M6 x M x 1.25 M10 x 1.5 M12 x 1.75 5.5 6.6 9.0 11.0 13.5 5.3 6.4 8.4 10.5 13.0 7.0 10.0 12.0 14.5 M14 x M16 x M20 x M24 x M30 x 2 2.5 3.5 15.5 17.5 22.0 26.0 33.0 15.0 17.0 21 o 25.0 31.0 16.5 18.5 24.0 28.0 35.0 M36 x M42 x 4.5 M48 x M56 x 5.5 M64x6 39.0 45.0 52.0 62.0 70.0 37.0 43.0 50.0 58.0 66.0 42.0 48.0 56.0 66.0 74.0 M72 x M80 x M90 x MlOO x 78.0 86.0 96.0 107.0 74.0 82.0 93.0 104.0 82.0 91.o 101.0 112.0 NOTES: (1) The clearance hole diameters given in the table are m i n i m u m sizes Recommended tolerances from ANSI B4.2 are H12 for close clearance holes, H13 for normal clearance holes, and H14 for loose clearance holes (2) Normal clearance hole sizes are preferred for general purpose applications, and should be specified unless special design considerations dictate the need for either a close or loose clearance hole (3) Close clearance hole sizes should be specified only where conditions, such as critical alignment of assembled parts, wall thickness, or other limitations, necessitate use of a minimal hole Whenclose clearance holes are specified, special provision (e.g., countersinking) may be needed at the screw entry side to permit proper seating of the screw head (4) Loose clearance hole sizes should be specified only for applications where maximum adjustment capability between components being assembled is necessary 17 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME B18.2.3.1M-1999 NONMANDATORY APPENDIX D COMPARISON WITH IS0 STANDARDS D l SCOPE in B 18.2.3.1MTable 3, are smaller than those per IS0 47594 for Product Grade B The maximum width across comers, E max., specified in B18.2.3.1M Table 3, is not specified in IS0 4014 or IS0 4017 Instead, the draft revision of IS0 47591 would control the shape of the hexagon by zero positional tolerance at maximummaterial condition, whichisnot specified in B 18.2.3.1M This Appendix summarizes thetechnical differences between ASME B 18.2.3.IM-1998 and I S 4014: 1988, IS0 4017: 1988, andrelated IS0 standards PRODUCT NAMES ”BOLT”AND “SCREW“ Of theproductsnamed“hexcapscrew”per B 18.2.3.1M thosethat are threaded full length are named“hexagon screw” per IS0 1891 or “hexagon head screw” per IS0 4017, but those that are not threaded full length are named “hexagon bolt” per IS0 189 or “hexagon head bolt” per IS0 40 14 The diameter limits for the chamfer circle or start of rounding on top of the head specified in B18.2.3.1M para 2.1.1 are not specified in IS0 4014, IS0 4017, or IS0 4759A D3 SIZES D6 HEADHEIGHT, K B18.2.3.IM omits IS0 4014 and IS0 4017 sizes M1.6-M4, M18, M22,M27, M33, M39,M45,MS2, and M60 B18.2.3.IM size MI0 with 15 mm width across flats,and sizes M72 x 6, M80 x 6, M90 x 6, and M 100 x are not included in IS0 4014 and IS0 4017, nor in I S 8676 and IS0 8765 For M8-M64, the maximumhead heights, K max., specified in B18.2.3.1M Table 3, are greater, and the minimum head heights, K min., specified in B18.2.3.1M Table 3, are less than those per I S 4014 or IS0 4017 For M72-Ml00, the limits for head heights, K, specified in B 18.2.3.1MTable 3, include greater tolerances than thoseper IS0 47594 for Product Grade B WIDTH ACROSSFLATS, ACROSSCORNERS, E D5 TOPOFHEAD S, AND WIDTH D7 WRENCHINGHEIGHT, K, For M5-M64, theminimum wrenching heights, K, min., specified in B18.2.3.IM Table 3, are greater than those per IS0 4014 and IS0 4017 For M72 and MSO, the minimum wrenching heights, K , min., specified in B 18.2.3.1M Table 3, are greater For M80 and M 100, theminimumwrenching heights, K , min.,specified in BI 8.2.3.1MTable 3, are less than those per I S 4759A Except for M10 with 15 mm width across flats, the maximum widths across flats, S max., specified in B 18.2.3.1M Table 3, agree with I S 4014 and IS0 40 I7 for M5-M64, and with IS0 272 for MS-M 100 For M5-M14 of nominal lengths over 10D, and MI6 of nominal lengths over 150 mm, the minimum widths across flatsand comers, S and E min., specified in B 18.2.3.1M Table 3, are greater than those per IS0 4014 or IS0 4017 For M20 and M24 of nominallengths 150 mm or less, and for M42-M64, theminimum widths across flatsand comers, S and E min., specified in B18.2.3.lM Table 3, are smaller thanthoseper IS0 4014 or IS0 4017 For M72-Ml00, the minimum widths across flatsand comers, S min.and E min., specified D8TRUE The position of head-to-shank tolerance zone diametersatmaximummaterialconditionspecified in B18.2.3.lM Table are: ( a ) for M5 of all lengths, and M6-Ml4 of lengths over 10D, less than those per IS0 40 14 and IS0 401 7; 19 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services POSITION OFHEAD NONMANDATORY APPENDIX D ASME 818.2.3.1M-1999 (b) for M8-MI4 of lengths under IOD, and M16M64 of all lengths, greater thanthoseper IS0 4014 and I S 4017; and (c) for M72-Ml00, greater than those per IS0 4759/ I for Product Grade B Position at maximummaterial condition, specified in B 18.2.3.1M, agrees with a draft revision of IS0 4759I , but differs from IS0 4759/1-1978, which specifies concentricity regardless of feature size D9 WASHERFACETHICKNESS, D l BODY DIAMETER, D, AND Dsi For M5-Ml4 of nominal lengths over IOD, M16M24 of nominal lengths over 150 mm, M30 and M36, the minimum body diameters, D, min.,specified in B18.2.3.I M Table 3, are greater thanthoseper IS0 40 14 For screws threaded full length, B18.2.3.lM Table specifies minimum diameters of unthreaded shank, D,5j min.,which are equal to the minimum pitchdiameter, while I S 4017 specifies “d, = pitch diameter.” C D l POINTS The minimum washer face thicknesses, C min., specified in B 18.2.3.1M Table 3, are thicker than those per IS0 4014 and IS0 4017 for M5-M64, and thicker than those per IS0 4759- for M72-M100 The maximum washer face thicknesses, C max., specified in B 18.2.3.I M Table 3, are thicker than those per IS0 4759/I for M80-MI00 D l WASHERFACEDIAMETER, The optional rounded point per B18.2.3.IM para 2.5 isnot in I S 4014 or I S 4017, but Table agrees with IS0 4753 D l STRAIGHTNESS The straightness tolerances specified in B 18.2.3.I M para 2.6 are: (a) for lengths up to12mm,lessthanthoseper IS0 4014 and IS0 4017, and (6) for lengths 16 mm and longer, greater than those per IS0 4014 and IS0 4017 D, For M5-Ml4 and M20-M64, the minimum washer face diameters, D, min., specified in B 18.2.3.1M Table 3, are different, larger or smaller, than those specified in IS0 4014 and IS0 4017 For M72-Ml00, the minimum washer face diameters, 0, min., specified in B 18.2.3 I M Table 3, are smaller than those per I S 4759D D l GRIP GAGING LENGTH, Lg, AND UNTHREADEDLENGTHUNDERHEAD, A, OFSCREWSTHREADEDFULL LENGTH D l RUNOUT OR PERPENDICULARITY OF BEARINGSURFACE-TO-SHANK For M5-M20 screws shorter than 2D, the maximum grip gaging lengths, Lg max., specified in B 18.2.3.1M Table 6, andthemaximumunthreaded lengths under head, A max., specified in B 18.2.3.1M Table 4, are shorter than those per I S 4017 The minimum unthreaded lengths under the head, A min., of screws threaded full lengthspecified in IS0 4017 are not specified in B18.2.3.IM B 18.2.3.1M para 2.1.6 specifies circular runout, measured as close totheperiphery ofthebearingsurface as possible, while IS0 4759/I specifies perpendicularity, i.e.,total runout, of thebearing surface fromthefillet transition diameter to a diameter equal to 0.8S, or, in the draft revision, 1.20 D l FILLET D l ROOTCONTOUR OF TRANSITION THREADS For screws threaded full length, theminimumfillet transition diameters, 0, min., and shorter maximum fillet lengths, Lf max., specified in B 18.2.3.IM Fig and Table 2, are notspecified in IS0 4017 For size MI00 x 6, themaximumfillettransition diameter, 0, max., specified in B 18.2.3.IM Table 2, is 107 mm, vs 108 mm per IS0 885 For sizes over M64, themaximumfillet lengths, Lf max., specified in BI 8.2.3 I M Table 2, are not given in IS0 standards The roundedroot contour of the transition threads, specified in 818.2.3 IM para 2.7.5, isnotspecified in I S 4014, IS0 4017, or IS0 965-1 D l POSITION OF BODY-TO-THREAD For M5-M I4 of lengths over IOD, and M16-M24 of lengths over 150 mm, the tolerance zone diameters 20 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services NONMANOATORY APPENDIX D ASME 818.2.3.1M-1999 for position of thebody with respect tothe thread, specified in B18.2.3.1M para 2.7.6 and Table I , are less than those per IS0 4014 and IS0 4017 Position at maximum material condition, specified in B 18.2.3.I M, agrees with a draft revision of IS0 4759-1, but differs from IS0 4759/1-1978, which specifies concentricity regardless of feature size The maximum heights of markings above the maximum head heights specified in B 18.2.3.IM para I O are notspecified in IS0 4014 and IS0 4017, nor in IS0 898-1 020 INSPECTION,QUALITYASSURANCE, DIMENSIONAL CONFORMANCE, AND ACCEPTABILITY D l MARKING The inspection, quality assurance, and dimensional conformance provisions in B 18.2.3.1M para I3 and 2.14 differ fromtheacceptabilityprovision in IS0 4014 or IS0 4017 B18.2.3 I M para I O requires marking on the top of the head, while IS0 898-1 requires marking on either the top orthe side of thehead 21 COPYRIGHT American Society of Mechanical Engineers Licensed by Information Handling Services ASME Services ASME is committed to developing and delivering technical information At ASME's Information Central, we make every effort to answer your questions and expedite your orders Our representatives are ready to assist you in the following areas: ASME Press Codes & Standards Credit Card Orders IMechE 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