1、BS ISO 2903:2016ISO metric trapezoidal screwthreads TolerancesBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 2903:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 2903:2016.The UK participation in its preparation was
2、 entrusted to TechnicalCommittee FME/9, Fasteners.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Sta
3、ndards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 91043 2ICS 21.040.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 September 2016
4、.Amendments/corrigenda issued since publicationDate Text affectedBS ISO 2903:2016 ISO 2016ISO metric trapezoidal screw threads TolerancesFiletages mtriques trapzodaux ISO TolrancesINTERNATIONAL STANDARDISO2903Third edition2016-09-01Reference numberISO 2903:2016(E)BS ISO 2903:2016ISO 2903:2016(E)ii I
5、SO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
6、the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09
7、 47copyrightiso.orgwww.iso.orgBS ISO 2903:2016ISO 2903:2016(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols 15 Tolerance system 26 Tolerance positions . 27 Tolerance grades 48 Length groups of thread engagement . 99 Recommended tolerance classes 1110 Multiple-sta
8、rt threads 1111 Formulae 1211.1 General 1211.2 Fundamental deviations 1211.3 Crest diameter tolerances 1311.3.1 Tolerances for major diameter of external thread (Td) .1311.3.2 Tolerances for minor diameter of internal thread (TD1) 1311.4 Pitch diameter tolerances . 1311.4.1 Tolerances for pitch diam
9、eter of external thread (Td2) 1311.4.2 Tolerances for pitch diameter of internal thread (TD2) .1311.5 Tolerances for minor diameter of external thread (Td3) .1411.6 Length groups of thread engagement 1412 Designation .1412.1 General 1412.2 Designation of single-start threads 1412.3 Designation of mu
10、ltiple-start screw threads . 1512.4 Designation of left-hand threads 15Bibliography .16 ISO 2016 All rights reserved iiiContents PageBS ISO 2903:2016ISO 2903:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bod
11、ies). 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 organizations, governmental and
12、 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.The procedures used to develop this document and those intended for its further maintenance are des
13、cribed in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn
14、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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the
15、 ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
16、as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.The committee responsible for this document is ISO/TC 1, Screw threads.This third edition cancels and replaces th
17、e second edition (ISO 2903:1993), Clauses 1, 13 and 14, and Table 7 of which have been technically revised (now Clauses 1, 11 and 12, and Table 5).iv ISO 2016 All rights reservedBS ISO 2903:2016INTERNATIONAL STANDARD ISO 2903:2016(E)ISO metric trapezoidal screw threads Tolerances1 ScopeThis document
18、 specifies a tolerance system for metric trapezoidal screw threads in accordance with ISO 2902. The tolerances refer to the design profile in accordance with ISO 2901.The tolerance system does not apply to trapezoidal screw threads with special requirements on axial displacement, for example, machin
19、e tool lead and feed screws and nuts.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition o
20、f the referenced document (including any amendments) applies.ISO 965-1, ISO general purpose metric screw threads Tolerances Part 1: Principles and basic dataISO 2901, ISO metric trapezoidal screw threads Basic and design profilesISO 2902, ISO metric trapezoidal screw threads General plan3 Terms and
21、definitionsFor the purposes of this document, the terms and definitions given in ISO 5408 apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at h
22、ttp:/www.iso.org/obp4 SymbolsFor the purposes of this document, the following symbols apply.D4basic major diameter of internal threadD nominal diameter (internal thread)D2basic pitch diameter of internal threadD1basic minor diameter of internal threadd basic major diameter of external thread (nomina
23、l diameter)d2basic pitch diameter of external threadd3basic minor diameter of external threadP pitchPh lead ISO 2016 All rights reserved 1BS ISO 2903:2016ISO 2903:2016(E)N designation for normal group of thread engagementL designation for long group of thread engagementT toleranceTD2, TD1, Td, Td2,
24、Td3tolerances for D2, D1, d, d2and d3, respectively (no tolerance for D4)EI, ei lower limit deviationsES, es upper limit deviations5 Tolerance systemThe system is based on the tolerance system for ISO general-purpose metric screw threads of ISO 965-1.6 Tolerance positionsThe following tolerance posi
25、tions are standardized for the pitch diameters. For internal threads: H with zero fundamental deviation (EI). See Figure 1. For external threads: c and e with negative fundamental deviation (es). See Figure 2.The tolerance position for the minor diameter (D1) and the major diameter (D4) of the inter
26、nal threads is always H, i.e. with zero fundamental deviation (EI).The tolerance position for the major diameter (d) and minor diameter (d3) of the external threads is in all cases h, i.e. with zero fundamental deviation (es), and it is independent of the tolerance positions of the pitch diameter.Th
27、e fundamental deviations for the pitch diameters of internal and external threads are given in Table 1.Figure 1 Internal threads with tolerance position H2 ISO 2016 All rights reservedBS ISO 2903:2016ISO 2903:2016(E)Figure 2 External threads with tolerance positions c and e for the pitch diameterTab
28、le 1 Fundamental deviations for the pitch diameters of internal and external threadsPitch PFundamental deviationsInternal threads D2External threads d2H EIc ese esmm m m m1,5 0 140 672 0 150 713 0 170 854 0 190 955 0 212 1066 0 236 1187 0 250 1258 0 265 1329 0 280 14010 0 300 15012 0 335 16014 0 355
29、 18016 0 375 19018 0 400 20020 0 425 21222 0 450 22424 0 475 23628 0 500 25032 0 530 26536 0 560 28040 0 600 30044 0 630 315 ISO 2016 All rights reserved 3BS ISO 2903:2016ISO 2903:2016(E)7 Tolerance gradesThe tolerance grades for the following screw thread diameters are standardized.Tolerance grades
30、Minor diameter of internal threads, D14Major diameter of external threads, d 4Pitch diameter of internal threads, D27 8 9Pitch diameter of external threads, d27 8 9Minor diameter of external threads, d37 8 9The tolerance grade for the minor diameter (d3) of the external thread is always the same as
31、for the pitch diameter (d2). However, the values for Td3and Td2are not the same for a same grade.The minor diameter tolerances of internal thread (TD1) are given in Table 2.The major diameter tolerances of external thread (Td) are given in Table 3.Table 2 Minor diameter tolerances of internal thread
32、s (TD1)Pitch PTolerance grade 4mm m1,5 1902 2363 3154 3755 4506 5007 5608 6309 67010 71012 80014 90016 1 00018 1 12020 1 18022 1 25024 1 32028 1 50032 1 60036 1 80040 1 90044 2 0004 ISO 2016 All rights reservedBS ISO 2903:2016ISO 2903:2016(E)Table 3 Major diameter tolerances of external threads (Td)
33、Pitch PTolerance grade 4mm m1,5 1502 1803 2364 3005 3356 3757 4258 4509 50010 53012 60014 67016 71018 80020 85022 90024 95028 1 06032 1 12036 1 25040 1 32044 1 400The pitch diameter tolerances of internal thread (TD2) are given in Table 4.The pitch diameter tolerances of external thread (Td2) are gi
34、ven in Table 5.Table 4 Pitch diameter tolerances of internal thread (TD2)Basic major diameter DPitch PTolerance gradeover up to and incl. 7 8 9mm mm mm m m m5,6 11,21,5 224 280 3552 250 315 4003 280 355 45011,2 22,42 265 335 4253 300 375 4754 355 450 5605 375 475 6008 475 600 750 ISO 2016 All rights
35、 reserved 5BS ISO 2903:2016ISO 2903:2016(E)Basic major diameter DPitch PTolerance gradeover up to and incl. 7 8 9mm mm mm m m m22,4 453 335 425 5305 400 500 6306 450 560 7107 475 600 7508 500 630 80010 530 670 85012 560 710 90045 903 355 450 5604 400 500 6308 530 670 8509 560 710 90010 560 710 90012
36、 630 800 1 00014 670 850 1 06016 710 900 1 12018 750 950 1 18090 1804 425 530 6706 500 630 8008 560 710 90012 670 850 1 06014 710 900 1 12016 750 950 1 18018 800 1 000 1 25020 800 1 000 1 25022 850 1 060 1 32024 900 1 120 1 40028 950 1 180 1 500180 3558 600 750 95012 710 900 1 12018 850 1 060 1 3202
37、0 900 1 120 1 40022 900 1 120 1 40024 950 1 180 1 50032 1 060 1 320 1 70036 1 120 1 400 1 80040 1 120 1 400 1 80044 1 250 1 500 1 900Table 4 (continued)6 ISO 2016 All rights reservedBS ISO 2903:2016ISO 2903:2016(E)Table 5 Pitch diameter tolerances of external thread (Td2)Basic major diameter dPitch
38、PTolerance gradeover up to and incl. 7 8 9mm mm mm m m m5,6 11,21,5 170 212 2652 190 236 3003 212 265 33511,2 22,42 200 250 3153 224 280 3554 265 335 4255 280 355 4508 355 450 56022,4 453 250 315 4005 300 375 4756 335 425 5307 355 450 5608 375 475 60010 400 500 63012 425 530 67045 903 265 335 4254 3
39、00 375 4758 400 500 6309 425 530 67010 425 530 67012 475 600 75014 500 630 80016 530 670 85018 560 710 90090 1804 315 400 5006 375 475 6008 425 530 67012 500 630 80014 530 670 85016 560 710 90018 600 750 95020 600 750 95022 630 800 1 00024 670 850 1 06028 710 900 1 120 ISO 2016 All rights reserved 7
40、BS ISO 2903:2016ISO 2903:2016(E)Basic major diameter dPitch PTolerance gradeover up to and incl. 7 8 9mm mm mm m m m180 3558 450 560 71012 530 670 85018 630 800 1 00020 670 850 1 06022 670 850 1 06024 710 900 1 12032 800 1 000 1 25036 850 1 060 1 32040 850 1 060 1 32044 900 1 120 1 400The minor diam
41、eter tolerances of external thread (Td3) are given in Table 6.Table 6 Minor diameter tolerances of external thread (Td3)Basic major diameter dPitch PTolerance position c of the pitch diameterTolerance position e of the pitch diameterTolerance grade Tolerance gradeoverup to and incl.7 8 9 7 8 9mm mm
42、mm m m m m m m5,6 11,21,5 352 405 471 279 332 3982 388 445 525 309 366 4463 435 501 589 350 416 50411,2 22,42 400 462 544 321 383 4653 450 520 614 365 435 5294 521 609 690 426 514 5955 562 656 775 456 550 6698 709 828 965 576 695 83222,4 453 482 564 670 397 479 5855 587 681 806 481 575 7006 655 767
43、899 537 649 7817 694 813 950 569 688 8258 734 859 1 015 601 726 88210 800 925 1 087 650 775 93712 866 998 1 223 691 823 1 048Table 5 (continued)8 ISO 2016 All rights reservedBS ISO 2903:2016ISO 2903:2016(E)Basic major diameter dPitch PTolerance position c of the pitch diameterTolerance position e of
44、 the pitch diameterTolerance grade Tolerance gradeoverup to and incl.7 8 9 7 8 9mm mm mm m m m m m m45 903 501 589 701 416 504 6164 565 659 784 470 564 6898 765 890 1 052 632 757 9199 811 943 1 118 671 803 97810 831 963 1 138 681 813 98812 929 1 085 1 273 754 910 1 09814 970 1 142 1 355 805 967 1 18
45、016 1 038 1 213 1 438 853 1 028 1 25318 1 100 1 288 1 525 900 1 088 1 32090 1804 584 690 815 489 595 7206 705 830 986 587 712 8688 796 928 1 103 663 795 97012 960 1 122 1 335 785 947 1 16014 1 018 1 193 1 418 843 1 018 1 24316 1 075 1 263 1 500 890 1 078 1 31518 1 150 1 338 1 588 950 1 138 1 38820 1
46、 175 1 363 1 613 962 1 150 1 40022 1 232 1 450 1 700 1 011 1 224 1 47424 1 313 1 538 1 800 1 074 1 299 1 56128 1 388 1 625 1 900 1 138 1 375 1 650180 3558 828 965 1 153 695 832 1 02012 998 1 173 1 398 823 998 1 22318 1 187 1 400 1 650 987 1 200 1 45020 1 263 1 488 1 750 1 050 1 275 1 53722 1 288 1 5
47、13 1 775 1 062 1 287 1 54924 1 363 1 600 1 875 1 124 1 361 1 63632 1 530 1 780 2 092 1 265 1 515 1 82736 1 623 1 885 2 210 1 343 1 605 1 93040 1 663 1 925 2 250 1 363 1 625 1 95044 1 755 2 030 2 380 1 440 1 715 2 0658 Length groups of thread engagementThe lengths of thread engagement are classified
48、into one of the two groups, normal (N) or long (L), in accordance with Table 7.Table 6 (continued) ISO 2016 All rights reserved 9BS ISO 2903:2016ISO 2903:2016(E)Table 7 Length groups of thread engagementDimensions in millimetresBasic major diameter D, dPitch PLength groups of thread engagementN Love
49、r up to and incl. over up to and incl. over5,6 11,21,5 5 15 152 6 19 193 10 28 2811,2 22,42 8 24 243 11 32 324 15 43 435 18 53 538 30 85 8522,4 453 12 36 365 21 63 636 25 75 757 30 85 858 34 100 10010 42 125 12512 50 150 15045 903 15 45 454 19 56 568 38 118 1189 43 132 13210 50 140 14012 60 170 17014 67 200 20016 75 236 23618 85 265 26590 1804 24 71 716 36 106 1068 45 132 13212 67 200 20014 75 236 23616 90 265 26518 100 300 300
