1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British StandardsWB9423_BSI_StandardColCov_noK_AW:BSI FRONT COVERS 5/9/08 12:55 Page 1British Standards for screw threads and screw gauges Introduction and guidanceBS 8498:2008BS 8498:2008 BritiSh St
2、andardPublishing and copyright informationthe BSi copyright notice displayed in this document indicates when the document was last issued. BSi 2008iSBn 978 0 580 58839 6iCS 21.040.01; 21.060.01the following BSi references relate to the work on this standard: Committee reference FME/9 draft for comme
3、nt 08/30165214 dCPublication historyFirst published december 2008Amendments issued since publicationAmd. No. Date Text affected BritiSh Standard BSI 2008 iBS 8498:2008Summary of pagesthis document comprises a front cover, an inside front cover, pages i to ii, pages 1 to 20, an inside back cover and
4、a back cover.ContentsForeword ii1 Scope 12 General 13 Whitworth threads and British association (B.a.) threads (BS 84:2007, BS 93:2008 and BS 9192:2007) 14 Unified threads (BS 15801:2007 and BS 15803:2007 and BS 9191:2007 and BS 9194:2007) 55 iSO metric threads (BS 36431:2007 and BS 36432:2007 and B
5、S 9193:2007) 146 Gauge blanks (BS 10441:2008) 16Bibliography 19List of tablestable 1 Screw thread standards and corresponding screw gauge standards 1table 2 Summary of data tabulated in BS 84:2007 (Whitworth threads) 2table 3 Summary of data tabulated in BS 93:2008 (B.a. threads) 3table 4 Summary of
6、 data tabulated in BS 9192:2007 (gauges and setting plugs for Whitworth and B.a. threads) 4table 5 Summary of data tabulated in BS 15801:2007 (Unified threads 14 in and larger) 6table 6 Summary of data tabulated in BS 15803:2007 (Unified threads below 14 in) 7table 7 Summary of data tabulated in BS
7、9191:2007 (gauges, setting plugs and check plugs for Unified threads) 9table 8 Summary of data tabulated in BS 9194:2007 for gauges, setting plugs and check plugs for Unified threads, coarse series 10table 9 Summary of data tabulated in BS 9194:2007 for gauges, setting plugs and check plugs for Unif
8、ied threads, fine series 11table 10 Summary of data tabulated in BS 9194:2007 for gauges, setting plugs and check plugs for Unified threads, extra fine series 13table 11 Summary of data tabulated in BS 36431:2007 for iSO metric screw threads 14table 12 Summary of data tabulated in BS 36432:2007 for
9、iSO metric screw threads 15table 13 Summary of data tabulated in BS 9193:2007 (gauges, setting plugs and check plugs for iSO metric threads) 16table 14 Summary of data tabulated in BS 10441:2008 for handles, nuts and collets 17table 15 Summary of data tabulated in BS 10441:2008 for gauge blanks for
10、plain plug gauges, screw plug gauges and segmental gauges 17table 16 Summary of data tabulated in BS 10441:2008 for gauge blanks for plain and screw ring gauges and plain gap gauges, solid type 17table 17 Summary of data tabulated in BS 10441:2008 for gauge blanks for adjustable screw ring gauges 18
11、BS 8498:2008ii BSI 2008BritiSh StandardForewordPublishing informationthis British Standard is published by BSi and came into effect on 31 december 2008. it was prepared by Subcommittee SFtSE/1, Screws and fasteners technical specification committee, under the authority of technical Committee FME/9,
12、Nuts, bolts and accessories. a list of organizations represented on this committee can be obtained on request to its secretary.Relationship with other publicationsthis British Standard gives a general introduction to two series of standards related to single start parallel screw threads, the series
13、specifying the screw threads (BS 84, BS 93, the two parts of BS 1580 and the two parts of BS 3643) and the series specifying the corresponding screw gauges (the BS 919 series and the standard for gauge blanks, BS 10441).Hazard warningsWARNING. attention is drawn to the fact that, with the different
14、screw thread forms available, there is the possibility of a mismatch, which is potentially hazardous. it is the responsibility of the designer 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.Use of
15、this documentas a guide, this British Standard takes the form of guidance and recommendations. it should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading.Presentational conventionsthe provisions in this standard ar
16、e presented in roman (i.e. upright) type. its recommendations are expressed in sentences in which the principal auxiliary verb is “should”.Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.Contractual and legal c
17、onsiderationsthis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.BritiSh Standard BSI 2008 1BS 8498:20081 Scopethis British Standard
18、 gives a general introduction to the series of British Standards specifying single start parallel screw threads of Whitworth, British association (B.a.), Unified and iSO metric forms, the series of British Standards specifying the corresponding screw gauges with which they are to be used, and the Br
19、itish Standard specifying the gauge blanks.2 Generalthe screw thread standards and the corresponding screw gauge standards are listed in table 1.NOTE For details of the British Standard for gauge blanks (BS 10441:2008), see Clause 6.table 1 Screw thread standards and corresponding screw gauge standa
20、rdsThread form Screw thread standard Screw gauge standardImperial unitsWhitworth BS 84:2007 BS 9192:2007a)Unified (H14 in) BS 15801:2007B)BS 9191:2007 and BS 9194:2007Unified (14 in) BS 15803:2007 BS 9191:2007Metric unitsBritish association (B.a.) BS 93:2008C)BS 9192:2007a), d)iSO metric BS 36431:20
21、07 BS 9193:2007BS 36432:2007 BS 9193:2007a)the gauges specified in this standard are also suitable for other thread forms such as BSC and BS Conduit.B)Superseded BS 1580 Parts 1 a) normal class external threads of sizes 0 B.a. to 10 B.a., and of b) sizes 11 B.a. to 16 B.a.;a single class of internal
22、 threads of sizes 0 B.a. to 16 B.a.c) a summary of the data tabulated in BS 93:2008 is given in table 3table 3 Summary of data tabulated in BS 93:2008 (B.A. threads)Sizes/Designation numbersData Thread type Thread class TableMetric data0 to 16 Basic sizes table 10 to 10 Limits and tolerances Externa
23、l Close table 20 to 10 Limits and tolerances External normal table 311 to 16 Limits and tolerances External normal table 40 to 16 Limits and tolerances internal table 5Approximate inch equivalents0 to 16 Basic sizes table d.10 to 10 Limits and tolerances External Close table d.20 to 10 Limits and to
24、lerances External normal table d.311 to 16 Limits and tolerances External normal table d.40 to 16 Limits and tolerances internal table d.5BS 8498:20084 BSI 2008BritiSh Standard3.2 GaugesBS 9192:2007 specifies the following gauges and setting plugs for Whitworth and B.a. threads:screw gauges for gene
25、ral and reference use:a) solid (nonadjustable) screw plug gauges, GO and nOt GO;1) solid and adjustable GO screw ring gauges;2) adjustable thread calliper gauges, GO and nOt GO;3) NOTE 1 NOT GO effective diameter ring gauges are also included since they have certain limited applications. In principl
26、e, however, their use is not recommended.plain plug gauges and plain calliper gauges for the crests of b) threads;NOTE 2 Provision is made in the standard for both GO and NOT GO plain gauges, but GO plain gauges are normally required only in the case of threads where the corresponding GO screw gauge
27、s do not control the maximum metal condition at the crests of the threads of the product.setting plugs for adjustable screw ring and thread calliper gauges, c) GO and nOt GO.a summary of the data tabulated in BS 9192:2007 is given in table 4.table 4 Summary of data tabulated in BS 9192:2007 (gauges
28、and setting plugs for Whitworth and B.A. threads)Gauge type Data GO/NOT GO Details of use TablePlug gaugesScrew plug gauges (General) Limits of tolerance GO table 1Screw plug gauges (reference) Limits of tolerance GO also for close fit workpiecestable 2Effective diameter plug gauges Limits of tolera
29、nce nOt GO all classes of workpiecetable 3Plain plug gauges for minor diametersLimits of tolerance GO and nOt GOall classes of workpiecetable 4Ring gauges and calliper gaugesScrew ring and thread calliper gauges (General)tolerances GO table 5Effective diameter ring gauges and thread calliper gaugesL
30、imits of tolerance nOt GO all classes of workpiecetable 6Plain calliper (GaP) gauges for major diameters tolerances GO and nOt GOall classes of workpiecetable 7Setting plugsSetting plugs for thread calliper or adjustable screw ring gauges (General)Limits of tolerance GO and nOt GO table 8Setting plu
31、gs for thread calliper or adjustable screw ring gauges (reference)Limits of tolerance GO table 9BritiSh Standard BSI 2008 5BS 8498:20084 Unified threads (BS 15801:2007 and BS 15803:2007 and BS 9191:2007 and BS 9194:2007)4.1 Screw threadsBS 15801:2007 (which is a revision of BS 1580 Parts 1 a fine th
32、read series (UnF) from 14 in to 112 in nominal diameter;an extra fine thread series (UnEF) from 14 in to 11116 in nominal diameter;standard constant pitch series:b) a 4threads per inch series (4 Un) from 2 58 in to 6 in nominal diameter;a 6threads per inch series (6 Un) from 1 716 in to 6 in nominal
33、 diameter;an 8threads per inch series (8 Un) from 1 116 in to 6 in nominal diameter; a 12threads per inch series (12 Un) from 58 in to 6 in nominal diameter;a 16threads per inch series (16 Un) from 716 in to 6 in nominal diameter;a 20threads per inch series (20 Un) from 516 in to 3 in nominal diamet
34、er;a 28threads per inch series (28 Un) from 516 in to 112 in nominal diameter;a 32threads per inch series (32 Un) from 716 in to 1 in nominal diameter;a special thread series (UnS) with diameter pitch combinations c) other than those specified for the standard series.BS 15803:2007 specifies external
35、 and internal threads, with nominal diameters below 14 in, from number 0 (0.060 in diameter) to number 12 (0.216 in diameter), known as the “numbered sizes”, in the following thread series:a coarse thread (UnC) series; a fine thread (UnF) series; for number 12 threads, an extra fine (UnEF) 32threads
36、 per inch diameter/pitch combination.a summary of the data tabulated in BS 15801:2007 is given in table 5. a summary of the data tabulated in BS 15803:2007 is given in table 6.BS 8498:20086 BSI 2008BritiSh Standardtable 5 Summary of data tabulated in BS 15801:2007 (Unified threads 14 in and larger)S
37、eries Data Thread type Thread class TableSummary tablesStandard thread data External and internalall table 26Standard diameter/pitch combinations External and internalall table 1Standard Limits of size External and internalall table 2Standard variable pitch seriesCoarse Basic dimensions External and
38、 internalall table 15Coarse Limits and tolerances External Class 1a table 3Class 2a table 5Class 3a table 7Coarse Limits and tolerances internal Class 1B table 4Class 2B table 6Class 3B table 8Fine Basic dimensions External and internalall table 16Fine Limits and tolerances External Class 1a table 9
39、Class 2a table 11Class 3a table 13Fine Limits and tolerances internal Class 1B table 10Class 2B table 12Class 3B table 14Extra fine Basic dimensions External and internalall table 17Standard constant pitch series4 t.p.i.a)Basic dimensions External and internal table 186 t.p.i. Basic dimensions Exter
40、nal and internal table 198 t.p.i. Basic dimensions External and internal table 2012 t.p.i. Basic dimensions External and internal table 2116 t.p.i. Basic dimensions External and internal table 2220 t.p.i. Basic dimensions External and internal table 2328 t.p.i. Basic dimensions External and internal
41、 table 2432 t.p.i. Basic dimensions External and internal table 25BritiSh Standard BSI 2008 7BS 8498:2008table 5 Summary of data tabulated in BS 15801:2007 (Unified threads 14 in and larger) (continued)Series Data Thread type Thread class TableSpecial series Variable pitch allowances External Class
42、1a and Class 2atable 28 Major diameter tolerances External Class 1a, Class 2a and Class 3atable 29 Effective diameter tolerances and minor diameter tolerancesExternal Class 1a table 30Class 2a table 31Class 3a table 32 Effective diameter tolerances internal Class 1B table 33Class 2B table 34Class 3B
43、 table 35 Minor diameter tolerances internal Class 1B, Class 2B and Class 3Btable 36Threads with decimal inch diametersCoarse and fine Preferred pitches table 37Special with preferred pitchesLimits of size External Class 2a and Class 3atable 38internal Class 2B and Class 3Ba)threads per inch.table 6
44、 Summary of data tabulated in BS 15803:2007 (Unified threads below 14 in)Series Data Thread type Thread class TableSummary tablesStandard thread data External and internalall table 16Standard diameter/pitch combinations External and internalall table 1Standard Limits of size External Class 2a and Cl
45、ass 3atable 2internal Class 2B and Class 3BBS 8498:20088 BSI 2008BritiSh Standardtable 6 Summary of data tabulated in BS 15803:2007 (Unified threads below 14 in) (continued)Series Data Thread type Thread class TableStandard constant pitch seriesCoarse Basic dimensions External and internalall table
46、13Coarse Limits and tolerances External Class 2a table 3Class 3a table 5Coarse Limits and tolerances internal Class 2B table 4Class 3B table 6Fine Basic dimensions External and internalall table 14Fine Limits and tolerances External Class 2a table 7Class 3a table 9Fine Limits and tolerances internal
47、 Class 2B table 8Class 3B table 10Extra fine Basic dimensions External and internalall table 15Extra fine Limits and tolerances External Class 2a and Class 3atable 11Extra fine Limits and tolerances internal Class 2B and Class 3Btable 124.2 Gauges4.2.1 BS 9191:2007 specifies the following gauges, se
48、tting plugs and check plugs:screw gauges:a) solid screw plug gauges, GO and nOt GO;1) solid screw ring gauges, GO and nOt GO;2) adjustable screw ring gauges, GO and nOt GO;3) adjustable screw calliper gauges, GO and nOt GO;4) setting plugs for adjustable ring gauges and for calliper gauges, b) GO an
49、d nOt GO:double length;1) single length;2) screw check plugs for solid screw ring gauges, GO and nOt GO; c) andplug gauges and calliper gauges for the crest diameters of d) product threads, GO and nOt GO.a summary of the data tabulated in BS 9191:2007 is given in table 7.NOTE All the tabulated values are tolerances.BritiSh Standard BSI 2008 9BS 8498:2008table 7 Summary of data tabulat
