1、BS 3643-1:2007ISO metric screw threadsPart 1: Principles and basic dataICS 21.040.10NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDIncorporating Corrigendum No.1Publishing and copyright informationThe BSI copyright notice displayed in this document indicates wh
2、en the document was last issued. BSI 2009ISBN 978 0 580 68655 9The following BSI references relate to the work on this standard: Committee reference FME/9 Draft for comment 07/30158486 DCPublication historyFirst published June 1963Second edition, March 1981 Third edition, November 2007Amendments iss
3、ued since publicationAmd. no. Date Text affectedBS 3643-1:2007C1 Figure A.1b correctedAnnex B, Example 1, d3corrected to d1in four placesAnnex B, Example 2, correction to formula for maximum pitch diameterAugust 2009 BSI 2009 iBS 3643-1:2007ContentsForeword iii1 Scope 12 Normative references 13 Term
4、s and definitions and symbols 14 Basic profile 25 General plan 56 Basic dimensions 87 Tolerances Principles and basic data 188 Tolerances Deviations for constructional threads 359 Tolerances Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with
5、 tolerance position H or G after galvanizing 5310 Tolerances Limits of sizes for internal screw threads to mate with hot-dip galvanized external screw threads with maximum size of tolerance position h before galvanizing 55AnnexesAnnex A (informative) Notes for guidance 60Annex B (informative) Exampl
6、es of calculations of limits of size for metric screw threads 65Bibliography 68List of figuresFigure 1 Basic profile of ISO metric thread 3Figure 2 Basic dimensions 8Figure 3 Tolerance positions with respect to zero line (basic size) 19Figure 4 Internal threads with tolerance position G 21Figure 5 I
7、nternal threads with tolerance position H 22Figure 6 External threads with tolerance positions e, f and g 22Figure 7 External threads with tolerance position h 23Figure 8 External root profile 31Figure A.1 Maximum material profiles for internal and external threads 61Figure B.1 Illustration of limit
8、s of size for external thread (see Example 1) 66List of tablesTable 1 Basic profile dimensions 4Table 2 Maximum nominal diameter 5Table 3 Diameter/pitch combinations 6Table 4 Basic dimensions 9Table 5 Fundamental deviations for internal threads and external threads 24Table 6 Lengths of thread engage
9、ment 25Table 7 Minor diameter tolerances of internal threads (TD1) 26Table 8 Major diameter tolerances of external threads (Td) 27Table 9 Pitch diameter tolerances of internal threads (TD2) 28Table 10 Pitch diameter tolerances of external threads (Td2) 29Table 11 Minimum root radii 31Table 12 Recomm
10、ended tolerance classes for internal threads 32Table 13 Recommended tolerance classes for external threads 32Table 14 Deviations 36Table 15 Deviations for hot-dip galvanized external threads 54BS 3643-1:2007ii BSI 2009Table 16 External thread limits for tolerance class 6az 55Table 17 Deviations for
11、internal threads to mate with hot-dip galvanized external threads 57Table 18 Internal screw thread limits for tolerance class 6AZ 58Table 19 Internal screw thread limits for tolerance class 6AX 59Table A.1 Nominal stress areas for external screw threads Coarse series 63Table A.2 Nominal stress areas
12、 for external screw threads Fine series 64Summary of pagesThis document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 68, an inside back cover and a back cover. BSI 2009 iiiBS 3643-1:2007ForewordPublishing informationThis part of BS 3643 is published by BSI and came into
13、effect on 30 November 2007. It was prepared by Subcommittee SFTSE/1, Screws and fasteners technical specification committee, under the authority of Technical Committee FME/9, Nuts, bolts and accessories. A list of organizations represented on this committee can be obtained on request to its secretar
14、y.SupersessionThis part of BS 3643 supersedes BS 3643-1:1981, which is withdrawn.Relationship with other publicationsThis part of BS 3643 is based on a series of BS ISO, and ISO, standards for ISO metric general purpose screw threads, each clause, from Clause 4 onwards, being based on one BS ISO, or
15、 ISO, as follows:Clause 4: Basic profile: BS ISO 68-1:1998;Clause 5: General plan: BS ISO 261:1998;Clause 6: Basic dimensions: ISO 724:1993;Clause 7: Tolerances Principles and basic data: BS ISO 965-1:1998;Clause 8: Tolerances Deviations for constructional screw threads: BS ISO 965-3:1998;Clause 9:
16、Tolerances Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanizing: BS ISO 965-4:1998;Clause 10: Tolerances Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw thre
17、ads with maximum size of tolerance position h before galvanizing: BS ISO 965-5:1998.BS 3643 consists of the following parts: Part 1: Principles and basic data; Part 2: Specification for selected limits of size.BS 3643-2 specifies the fundamental deviations, tolerances and limits of size for the tole
18、rances classes 4H, 5H, 6H and 7H for internal threads and 4h, 6g and 8g for external threads where appropriate for: a course pitch series with the range 1 mm to 68 mm diameter; a fine pitch series with the range 1 mm to 33 mm diameter; a constant pitch series with the range 8 mm to 300 mm diameter.I
19、nformation about this documentNo. 1 is indicated in the text by tags PQ.The start and finish of text introduced or altered by Corrigendum BS 3643-1:2007iv BSI 2009Information about this documentThis part of BS 3643 has been revised to bring it up to date. The 1981 edition of the standard was based o
20、n ISO 68:1963, ISO 261:1973, ISO 724:1968, ISO 965-1:1980 and ISO 965-3:1980. These standards have all been withdrawn and superseded and this part of BS 3643 has been revised to reflect the latest editions of these standards (see above).Two extra clauses have been added to this revision, based on BS
21、 ISO 965-4:1998 and BS ISO 965-5:1998, respectively.This part of BS 3643 does not include a clause based on BS ISO 965-2:1998. Selected limits of size for use in the UK are specified in BS 3643-2:2007.This part of BS 3643 also does not include a clause based on BS ISO 262:1998 as these sizes can be
22、expected to be specified in the relevant product standards. However, the data given in BS ISO 262:1998 have been included in Table 3.Additional guidance notes are given in Annex A. These notes are presented separately so as not to disrupt the correspondence between the clauses of the main text and t
23、he BS ISO, or ISO, standards on which they are based. Information is given in Annex B on calculating limits of size for metric screw threads for which dimensions are not given in the tables in this part of BS 3643. This information is given because it is recognized that the limitations placed by the
24、 BS ISO and ISO standards on nominal sizes and on the diameter/pitch combinations, might in certain cases need to be exceeded.Hazard warningsContractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its corr
25、ect application.Compliance with a British Standard cannot confer immunity from legal obligations.WARNING. Attention is drawn to the fact that, with the different screw thread forms available, there is the possibility of mismatch, which is potentially hazardous. It is the responsibility of the design
26、er of the end product to ensure that this possibility is reduced to a minimum. For further information on mismatches of screw thread systems see PD 6494. BSI 2009 1BS 3643-1:20071 ScopeThis part of BS 3643 gives a compilation of principles and basic data for single-start, parallel screw threads havi
27、ng the ISO basic profile for triangular screw threads. Guidance on calculating limits of size for metric screw threads not included in Tables 1 to 14 is given inAnnex B. 2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated referen
28、ces, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.BS 919-3, Screw gauge limits and tolerances Part 3: Specification for gauges for screw threads of ISO metric formBS 6528:1984, Glossary of terms for cylindric
29、al screw threads3 Terms and definitions and symbols3.1 Terms and definitionsFor the purposes of this part of BS 3643 the terms and definitions given in BS 6528:1984 apply together with the following.3.1.1 basic profiletheoretical profile of a screw thread in an axial plane defined by theoretical dim
30、ensions and angles common to internal and external threadsNOTE 1 This definition is repeated from BS 6528:1984 for the convenience of users of this standard.NOTE 2 The basic profile is shown as a thick line in Figure 1.BS 3643-1:20072 BSI 20093.2 SymbolsFor the purposes of this part of BS 3643 the f
31、ollowing symbols apply.D basic major diameter of internal thread (nominal diameter)D1basic minor diameter of internal threadD2basic pitch diameter of internal threadd basic major diameter of external thread (nominal diameter)d1basic minor diameter of external threadd2basic pitch diameter of external
32、 threadd3minor diameter of external threadH height of fundamental triangleP pitchT toleranceTD1tolerances for D1TD2tolerances for D2Td1tolerances for d1Td2tolerances for d2ei, EI lower deviations (see Figure 2)es, ES upper deviations (see Figure 2)R root radius of external threadC root truncation of
33、 external threadS designation for thread engagement group “short”N designation for thread engagement group “normal”L designation for thread engagement group “long”4 Basic profile4.1 GeneralThis clause specifies the basic profile for ISO general purpose metric screw threads as shown in Figure 1. The
34、dimensions for the various standard pitches are given in Table 1.4.2 DimensionsThe fundamental deviations and tolerances specified in Clause 7 are applied to the dimensions of the basic profile shown in Figure 1 and derived from Table 1.H32- P 0.866i025i404P=58- H 0.541i265i877P=38- H 0.324i759i526P
35、=H4- 0 . 2 1 6 i506i351P=H8- 0 . 1 0 8 i253i175P= BSI 20093BS 3643-1:2007Figure 1 Basic profile of ISO metric thread90(5/8)HP/8PP/2P/43060Axis of screw threadH/4H/8(3/8)HHDdD1D2d1d2BS 3643-1:20074 Table 1 Basic profile dimensionsDimensions in millimetresPitchPH0.2 0.173 205 0.108 253 0.064 952 0.043
36、 301 0.021 651 0.25 0.216 506 0.135 316 0.081 190 0.054 127 0.027 063 0.3 0.259 808 0.162 380 0.097 428 0.064 952 0.032 4760.35 0.303 109 0.189 443 0.113 666 0.075 777 0.037 889 0.4 0.346 410 0.216 506 0.129 904 0.086 603 0.043 301 0.45 0.389 711 0.243 570 0.146 142 0.097 428 0.048 7140.5 0.433 013
37、0.270 633 0.162 380 0.108 253 0.054 127 0.6 0.519 615 0.324 760 0.194 856 0.129 904 0.064 952 0.7 0.606 218 0.378 886 0.227 332 0.151 554 0.075 7770.75 0.649 519 0.405 949 0.243 570 0.162 380 0.081 190 0.8 0.692 820 0.433 013 0.259 808 0.173 205 0.086 603 1 0.866 025 0.541 266 0.324 760 0.216 506 0.
38、108 2531.25 1.082 532 0.676 582 0.405 949 0.270 633 0.135 316 1.5 1.299 038 0.811 899 0.487 139 0.324 760 0.162 380 1.75 1.515 544 0.947 215 0.568 329 0.378 886 0.189 4432 1.732 051 1.082 532 0.649 519 0.433 013 0.216 506 2.5 2.165 063 1.353 165 0.811 899 0.541 266 0.270 633 3 2.598 076 1.623 798 0.
39、974 279 0.649 519 0.324 7603.5 3.031 089 1.894 431 1.136 658 0.757 772 0.378 886 4 3.464 102 2.165 063 1.299 038 0.866 025 0.433 013 4.5 3.897 114 2.435 696 1.461 418 0.974 279 0.487 1395 4.330 127 2.706 329 1.623 798 1.082 532 0.541 266 5.5 4.763 140 2.976 962 1.786 177 1.190 785 0.595 392 6 5.196
40、152 3.247 595 1.948 557 1.299 038 0.649 5198 6.928 203 4.330 127 2.598 076 1.732 051 0.866 02558- H38- HH4-H8- BSI 2009 5BS 3643-1:20075 General plan5.1 GeneralThis clause specifies ISO general purpose metric screw threads having the basic profile as defined in Clause 4.5.2 DesignationA screw thread
41、 conforming to this part of BS 3643 shall be designated in accordance with Clause 7.5.3 Choice of diameter and pitchNOTE Table 3 has been retained unaltered from the 1981 edition of BS 3643-1.5.3.1 Choose, for preference, diameters in column 1 of Table 3 and, if necessary, in column 2 and then in co
42、lumn 3.Diameter 35 mm, and pitch 1.25 mm of diameter 14 mm shall be used only for the special cases indicated in the footnotes.Pitches shown in parentheses are to be avoided as far as possible.5.3.2 The words “coarse” and “fine” are given in order to conform to usage. No concept of quality shall, ho
43、wever, be associated with these words.It shall be understood that the “coarse” pitches are the largest metric pitches used in current practice.5.3.3 For the diameter (or the diameter range) selected, choose one of the pitches shown on the corresponding line (or lines).5.3.4 If screw threads finer th
44、an those appearing in Table 3 are found necessary, only the following pitches shall be used:3 mm; 2 mm; 1.5 mm; 1 mm; 0.75 mm; 0.5 mm; 0.35 mm; 0.25 mm; 0.2 mm.When selecting such pitches, take into account the fact that there is increasing difficulty in complying with tolerances as the diameter is
45、increased for a given pitch. It is suggested that diameters larger than those shown in Table 2 should generally not be used with the pitches indicated.Table 2 Maximum nominal diameterDimensions in millimetresPitch Maximum nominal diameter0.5 22 0.75 33 1 80 1.5 150 2 200 33 BSI 2009BS 3643-1:20076 T
46、able 3 Diameter/pitch combinationsDimensions in millimetresNominal diameters PitchesColumn 1 1stchoiceColumn 2 2nd choiceColumn 3 3rd choiceCoarse seriesFine seriesConstant series3 2 1.5 1.25 1 0.751 0.25 0.21.1 0.25 0.2 1.2 0.25 0.2 1.4 0.3 0.21.6 0.35 0.2 1.8 0.35 0.2 2 0.4 0.252.2 0.45 0.25 2.5 0
47、.45 0.353 0.5 0.353.5 0.6 0.35 4 0.7 0.5 4.5 0.75 0.55 0.8 0.5 5.5 (0.5) 6 1 0.757 1 0.75 8 1.25 1 0.75 9 1.25 1 0.7510 1.5 1.25 1 0.75 11 1.5 1 0.7512 1.75 1.25 1.5 1 14 2 1.5 1.25A)115 1.5 1 16 2 1.5 117 1.5 1 18 2.5 1.5 2 1 20 2.5 1.5 2 122 2.5 1.5 2 1 24 3 2 1.5 1 25 2 1.5 126 1.5 27 3 2 1.5 1 2
48、8 2 1.5 130 3.5 2 (3) 1.5 132 2 1.5 33 3.5 2 (3) 1.5 35B)1.5 36 4 3 2 1.538 1.5 39 4 3 2 1.5Pitches shown in parentheses are to be avoided as far as possible.A)Only for spark plugs for engines.B)Only for locking nuts for bearings. BSI 2009 BSI 2009 7BS 3643-1:2007Table 3 Diameter/pitch combinations
49、(continued)Dimensions in millimetresNominal diameters PitchesColumn 11st choiceColumn 22nd choiceColumn 33rd choiceCoarse seriesConstant series64321.540 3 2 1.5 42 4.5 4 3 2 1.5 45 4.5 4 3 2 1.548 5 4 3 2 1.5 50 3 2 1.5 52 5 4 3 2 1.555 4 3 2 1.5 56 5.5 4 3 2 1.5 58 4 3 2 1.560 5.5 4 3 2 1.5 62 4 3 2 1.5 64 6 4 3 2 1.565 4 3 2 1.5 68 6 4 3 2 1.5 70 6 4 3 2 1.572 6 4 3 2 1.5 75 4 3 2 1.5 76 6 4 3
