1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 888:2012Fasteners Bolts, screws andstuds Nominal lengths andthread lengthsBS ISO 888:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation o
2、f ISO 888:2012. Itsupersedes BS 7345:1990 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee FME/9/2, Fasteners - Reference Standards.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not
3、 purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 71176 3ICS 21.060.10Compliance with a British Standard cannot confer immunity fromlegal obliga
4、tions.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 888:2012 ISO 2012Fasteners Bolts, screws and studs Nominal lengths and thread lengthsFixations Vis, goujons
5、 et tiges filetes Longueurs nominales et longueurs filetesINTERNATIONAL STANDARDISO888Second edition2012-04-15Reference numberISO 888:2012(E)BS ISO 888:2012ISO 888:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of t
6、his publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-121
7、1 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 888:2012ISO 888:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Symbols . 14 Position of lengths and thread lengths . 14.1 G
8、eneral . 14.2 Bolts and screws . 24.3 Headless screws and set screws 34.4 Studs and similar fasteners 35 Dimensions for lengths . 56 Dimensions for thread lengths 6BS ISO 888:2012ISO 888:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national sta
9、ndards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International or
10、ganizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given
11、 in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75
12、% of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 888 was prepared by Technical Committee ISO/TC 2, Fasteners,
13、 Subcommittee SC 7, Reference standards.This second edition cancels and replaces the first edition (ISO 888:1976), which has been technically revised.iv ISO 2012 All rights reservedBS ISO 888:2012INTERNATIONAL STANDARD ISO 888:2012(E)Fasteners Bolts, screws and studs Nominal lengths and thread lengt
14、hs1 ScopeThis International Standard specifies lengths and thread lengths for bolts, screws and studs for use in appropriate product standards and other relevant documents, e.g. for parts per drawing.It applies to bolts, screws and studs with ISO metric screw thread according to ISO 68-1.2 Normative
15、 referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 68-1, ISO general purpose screw thr
16、eads Basic profile Part 1: Metric screw threadsISO 225, Fasteners Bolts, screws, studs and nuts Symbols and descriptions of dimensionsISO 4753, Fasteners Ends of parts with external ISO metric threadISO 4759-1, Tolerances for fasteners Part 1: Bolts, screws, studs and nuts Product grades A, B and C3
17、 Symbolsb thread lengthb1thread length of one end for double-end studb2thread length of the other end for double-end studbmthread length of the stud metal endd basic major diameter (nominal diameter) of the threadl nominal length (of the bolt, screw or stud)lgdistance from the bearing face to the fi
18、rst full form (full profile) thread (bolt), as specified in ISO 225lslength of the unthreaded shankP pitch of the thread4 Position of lengths and thread lengths4.1 GeneralThe nominal length, l, and the thread length, b, features for bolts, screws and studs are specified in ISO 225.Points for bolts a
19、nd screws are usually included in the length and thread length, except for the pilot point; they are specified in ISO 4753. ISO 2012 All rights reserved 1BS ISO 888:2012ISO 888:2012(E)4.2 Bolts and screwsFor bolts and screws with effective bearing surface perpendicular to the axis, the length shall
20、be defined from the bearing face to the end of the bolt or screw; see Figure 1.Figure 1 Length for bolts and screws with effective bearing surface perpendicular to the axisFor flat countersunk bolts and screws, the length shall be defined from the upper edge of the head to the end of the bolt or scr
21、ew; see Figure 2.Figure 2 Length for bolts and screws with flat countersunk headFor raised countersunk bolts and screws, the length shall be defined from the theoretical intersection of the top surface of the head with the head diameter to the end of the bolt or screw; see Figure 3.Figure 3 Length f
22、or bolts and screws with raised countersunk headFor concave bearing surfaces, serrated bearing surface and similar, the length shall be defined from the effective bearing plane of the bearing face to the end of the bolt or screw; see Figures 4 and 5.2 ISO 2012 All rights reservedBS ISO 888:2012ISO 8
23、88:2012(E)Figure 4 Length for bolts and screws with concave bearing surfaceFigure 5 Length for bolts and screws with serrated bearing surface4.3 Headless screws and set screwsFor headless screws and set screws, the length shall be defined from one extreme end to the other; see Figures 6 and 7.Figure
24、 6 Length for headless screws with shankFigure 7 Length for set screws4.4 Studs and similar fastenersFor partially threaded studs (double-end studs), the length shall be defined from the thread run-out at the metal end to the end of the stud at the nut end; see Figure 8.NOTE The thread length of the
25、 stud metal end, bm, according to ISO 225, is not within the scope of this International Standard. ISO 2012 All rights reserved 3BS ISO 888:2012ISO 888:2012(E)Key1 stud metal end2 nut endFigure 8 Length for partially threaded studs (two threaded ends/shanks)For tie rods (double-end studs with right-
26、 and left-hand threads/tensioning studs), for partially threaded studs (single-end stud), for totally threaded studs with points (chamfer or flat) and totally threaded studs (threaded rods/studding), the length shall be defined from one extreme end to the other; see Figures 9 to 12.Figure 9 Length f
27、or tie rodFigure 10 Length for partially threaded studs (single-end stud)Figure 11 Length for totally threaded studs (continuous thread)Figure 12 Length for totally threaded studs (threaded rods)4 ISO 2012 All rights reservedBS ISO 888:2012ISO 888:2012(E)5 Dimensions for lengthsDimensions for the le
28、ngths are specified in Table 1.Table 1 Lengths for ISO metric bolts, screws and studsDimensions in millimetresProduct grade Product gradeA B C A B Cl lminlmaxlminlmaxlminlmaxl lminlmaxlminlmaxlminlmax2 1,80 2,20 (85) 84,30 85,70 83,25 86,75 83,25 86,75(2,5) 2,30 2,70 90 89,30 90,70 88,25 91,75 88,25
29、 91,753 2,80 3,20 (95) 94,30 95,70 93,25 96,75 93,25 96,754 3,76 4,24 100 99,30 100,70 98,25 101,75 98,25 101,755 4,76 5,24 (105) 104,30 105,70 103,25 106,75 103,25 106,756 5,76 6,24 110 109,30 110,70 108,25 111,75 108,25 111,75(7) 6,71 7,29 (115) 114,30 115,70 113,25 116,75 113,25 116,758 7,71 8,29
30、 120 119,30 120,70 118,25 121,75 118,25 121,75(9) 8,71 9,29 (125) 124,20 125,80 123,00 127,00 123,00 127,0010 9,71 10,29 9,25 10,75 9,25 10,75 130 129,20 130,80 128,00 132,00 128,00 132,00(11) 10,65 11,35 10,10 11,90 10,10 11,90 140 139,20 140,80 138,00 142,00 138,00 142,0012 11,65 12,35 11,10 12,90
31、 11,10 12,90 150 149,20 150,80 148,00 152,00 148,00 152,00(14) 13,65 14,35 13,10 14,90 13,10 14,90 160 159,20 160,80 158,00 162,00 156,00 164,0016 15,65 16,35 15,10 16,90 15,10 16,90 (170) 169,20 170,80 168,00 172,00 166,00 174,00(18) 17,65 18,35 17,10 18,90 17,10 18,90 180 179,20 180,80 178,00 182,
32、00 176,00 184,0020 19,58 20,42 18,95 21,05 18,95 21,05 (190) 189,10 190,90 187,70 192,30 185,40 194,60(22) 21,58 22,42 20,95 23,05 20,95 23,05 200 199,10 200,90 197,70 202,30 195,40 204,6025 24,58 25,42 23,95 26,05 23,95 26,05 220 219,10 220,90 217,70 222,30 215,40 224,60(28) 27,58 28,42 26,95 29,05
33、 26,95 29,05 240 239,10 240,90 237,70 242,30 235,40 244,6030 29,58 30,42 28,95 31,05 28,95 31,05 260 257,40 262,60 254,80 265,20(32) 31,50 32,50 30,75 33,25 30,75 33,25 280 277,40 282,60 274,80 285,2035 34,50 35,50 33,75 36,25 33,75 36,25 300 297,40 302,60 294,80 305,20(38) 37,50 38,50 36,75 39,25 3
34、6,75 39,25 320 317,15 322,85 314,30 325,7040 39,50 40,50 38,75 41,25 38,75 41,25 340 337,15 342,85 334,30 345,7045 44,50 45,50 43,75 46,25 43,75 46,25 360 357,15 362,85 354,30 365,7050 49,50 50,50 48,75 51,25 48,75 51,25 380 377,15 382,85 374,30 385,7055 54,40 55,60 53,50 56,50 53,50 56,50 400 397,1
35、5 402,85 394,30 405,7060 59,40 60,60 58,50 61,50 58,50 61,50 420 416,85 423,15 413,70 426,3065 64,40 65,60 63,50 66,50 63,50 66,50 440 436,85 443,15 433,70 446,3070 69,40 70,60 68,50 71,50 68,50 71,50 460 456,85 463,15 453,70 466,30(75) 74,40 75,60 73,50 76,50 73,50 76,50 480 476,85 483,15 473,70 48
36、6,3080 79,40 80,60 78,50 81,50 78,50 81,50 500 496,85 503,15 493,70 506,30Nominal lengths in parentheses (brackets) should be avoided, if possible.Tolerances for length are calculated in accordance with ISO 4759-1. ISO 2012 All rights reserved 5BS ISO 888:2012ISO 888:2012(E)6 Dimensions for thread l
37、engthsUnless otherwise specified in a product standard, dimensions for thread lengths, b (see Table 2), shall be calculated as follows: for l 125 mm: b = 2d + 6 mm for 125 mm 200 mm: b = 2d + 25 mmWhen the calculation for shorter bolts results in a shank (unthreaded portion) of length 0,5d, the bolt
38、 should be fully threaded.Table 2 Thread lengths for ISO metric bolts, screws and studsDimensions in millimetresThread diameter d1,6 2 2,5 3 4 5 6 8 10 12 (14) 16 18 20 22Thread length bl 125 9 10 11 12 14 16 18 22 26 30 34 38 42 46 50125 200 57 61 65 69Thread diameter d24 27 30 33 36 39 42 45 48 52
39、 56 60 64 68 72Thread length bl 125 54 60 66 72 78 84 90 96 102 125 200 73 79 85 91 97 103 109 115 121 129 137 145 153 161 169Thread diameter d76 80 85 90 95 100 105 110 115 120 125 130 140 150 160Thread length bl 125 125 200 177 185 195 205 215 225 235 245 255 265 275 285 305 325 345Tolerances for
40、thread lengths are specified in ISO 4759-1 as follows:a) for bolts and screws with drives (e.g. hexagon head, hexagon head with flange, hexagon socket head cap, hexalobular cylindrical head, cup head square neck, hexagon or hexalobular countersunk head bolts and similar bolts specified in ISO 225),
41、the tolerances are expressed in terms of lgand ls, and are specified in product standards according to the following: lg,max= lnom b ls,min= lg,max 5Pb) for slotted or recessed screws and similar screws (e.g. pan head, cheese head, countersunk head specified in ISO 225) and studs, the tolerance for
42、b is +20P.6 ISO 2012 All rights reservedBS ISO 888:2012BS ISO 888:2012ISO 888:2012(E) ISO 2012 All rights reservedICS 21.060.10Price based on 6 pagesThis page deliberately left blankBSI is the independent national body responsible for preparing British Standards and other standards-related publicati
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