1、BS 919-2:2007S c r e w g a u g e l i m i t s a n d t o l e r a n c e s Part 2: Specification for gauges for screw threads of Whitworth and B.A. formsICS 21.040.20NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDIncorporating Corrigendum No.1Publishing and copyrig
2、ht informationThe BSI copyright notice displayed in this document indicates when the document was last issued.The following BSI references relate to the work on this standard: Committee reference TDW/4Publication historyFirst published 1940 Second edition,December 1952 Third edition, November 1971 F
3、ourth edition, November 2007Amendments issued since publicationAmd. no. Date T e x t a f f e c t e dBS 919-2:2007 BSI 200ISBN978 0 580 976 586Draft for comment 07/30158515 DC3C1 See foreword30 September 2009 iBS 919-2:2007ContentsForeword iii1 Scope 12 Normative references 13 Terms and definitions a
4、ndsymbols 24 Design 35 Disposition of gauge tolerance zones 46 Gauges for internal screw threads 67 Gauges for external screw threads and their setting plugs 78 Marking 10AnnexesAnnex A (informative)Function and method of use of various gauge types 21Annex B (informative) Conventional illustration o
5、f tolerance zones 25Annex C (informative) Effective diameter equivalent of pitch and angle errors 26Annex D (normative)Thread formof NOT GO effective diameter gauges 29Annex E (informative)Hardness 33Bibliography 34List of figuresFigure 1 Disposition of effective diameter tolerance zones for screw g
6、auges 5Figure 2 Forms of thread of GO screw gauges 8Figure 3 General GO screw plug gauges 11Figure 4 Reference GO screw plug gauges 12Figure 5 NOT GO effective diameter plug gauges 13Figure 6 GO and NOT GO plain plug gauges for minor diameters 14Figure 7 General GO screw ring and GO thread calliper
7、gauges 15Figure 8 NOT GO effective diameterring gauges and thread calliper gauges 16Figure 9 GOand NOT GO plain calliper (GAP) gauges for major diameters 17Figure 10 General setting plugs for thread calliper or adjustable screw ring gauges 18Figure 11 Reference settings plugs for GOthread calliper o
8、radjustable screwring gauges 20Figure B.1 Diagram showing limitsand tolerances for the effective diameters ofanut and itsmating bolt 25Figure D.1 Forms of thread forNOT GO effective diameter screw gauges: Plug and ring gauges 32Figure D.2 Calliper gauge anvils 32List of tablesTable 1 Limits of toler
9、ance for General GO screw pluggauges 11Table 2 Limits of tolerance for Reference GO screw plug gauges (for use also for Close fit workpieces) 12Table 3 Limits of tolerancefor NOT GO effective diameter plug gauges (All classes of workpiece) 13Table 4 Limits of tolerance for GO and NOT GO plain plug g
10、auges for minor diameters (All classes of workpiece) 14 BSI 2009BS 919-2:2007iiTable 5 Tolerances for General GO screw ring and GO thread calliper gauges 15Table 6 Limits of tolerance for NOT GO effective diameterring gauges and thread calliper gauges (All classes of workpiece) 16Table 7 Tolerances
11、for GO and NOT GOplain calliper (GAP) gauges for major diameters (All classes of workpiece) 17Table 8 Limits of tolerance for General setting plugs for thread calliper or adjustable screwring gauges 19Table 9 Limits of tolerance for Reference setting plugs for GO thread calliper or adjustable screw
12、ring gauges 20Table C.1 Effective diameterequivalents of errors in pitch 27Table C.2 Effective diameterequivalents of errors in angle for Whitworth threads 28Table C.3 Effective diameterequivalent of errors in angle for B.A. threads 28Table C.4 Effective diameterequivalents of errors in angle for BS
13、C threads 29Table D.1 Whitworth threads 30Table D.2 BSC threads 30Table D.3 B.A. threads 31Summary of pagesThis document comprises a front cover, an inside front cover, pagesitoiii, a blank page, pages 1 to 34, an inside back cover and a back cover. BSI 2009 iiiBS 919-2:2007F o r e w o r dPublishing
14、 informationThis British Standard is published by BSI and came into effect on 30November2007. It was prepared by Subcommittee SFTSE/1, Screws and fasteners technical specification committee, under the authority of Technical Committee TDW/4, Technical product realization. A list of organizations repr
15、esented on thesecommitteescan be obtained on request to their secretaries.BS 919, Screw gauge limits and tolerances is in four parts:Part 1: Specification for gauges for screw threads of unified formPart 2: Specification for gauges for screw threads of Whitworth and B.A. formsPart 3: Specification f
16、or gauges for screw threads of ISO metric formPart 4: Limits of size for gauges for screw threads of unified form diameters in and largerSupersessionThis Part of BS 919 supersedesBS 919-2:1971, which is withdrawn.Relationship with other publicationsThis British Standard is intended for use with BS 8
17、4, which specifies the corresponding screw threads.Information about this documentThis British Standard has been fully revised to bring it up to date.Presentational conventionsThe provisionsof this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in wh
18、ich the principal auxiliary verb is “shall”.Commentary, explanation and general informative material is presented in notes in smaller italic type, and does not constitute a normative element.Contractual and legal considerationsThis publication does not purport to include all the necessaryprovisions
19、of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.14- - -No. 1 is indicated in the text by tags PQ. BSI 2009The start and finish of text introduced or altered by Corrigendum iv This page deliberately left
20、 blankBS 919-2:2007 BSI 2009 1BS 919-2:20071ScopeThis Part of BS 919 specifies requirements for the following gauges intended for checking screw threads in the regular series, suchasBS Whit., BS Fine, B.A., BSC and BS Conduit.a) Screw gauges for general and reference use:1) solid (non-adjustable) sc
21、rew plug gauges, GO and NOT GO;2) solid and adjustable GO screw ring gauges;3) adjustable thread calliper gauges, GO and NOT GO.NOTE NOT GO effective diameter ring gauges are also included since they have certain limited applications. In principle, however, their use isnot recommended.b) Plain plug
22、gaugesand plain calliper gauges for the crests of threads.NOTE Provision is made in the standard for both GO and NOT GO plaingauges, but GO plain gauges are normally required only in the case of threads where the corresponding GO screw gauges do not control the maximum metal condition at the crests
23、of the threads of the product.c) Setting plugs for adjustable screw ringand thread calliper gauges, GO and NOT GO.This standard may be applied also to gauges for any screw threads of Whitworth form, but not to gauges for Acme, buttress or round threads.Annex A provides guidance on the various types
24、of gauges.Information relating to the effective diameter equivalent of pitch and angle errors and to the thread form of NOT GO effective diameter gauges is given in Annex B, Annex C and Annex D.No requirements are specified for the materials for gauges, but guidance on the hardness of gauges is give
25、n in Annex E.2The 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.BS 84, Parallel screw threads of Whit
26、worth form RequirementsBS 1044-1:1964, Specification for gauge blanks Part 1: Plug, ring and calliper gaugesBS 6528:1984, Glossary of terms for cylindrical screw threadsQP BSI 2009BS 919-2:200723Terms andefitons adymbols3.1 Terms and definitionsFor the purposes of this part of BS919, the terms and d
27、efinitions given in BS 6528:1984 and the following apply.3.1.1 effective diameterdiameter of the pitch cylinderNOTE 1 This is the “simple” effective diameter, as distinct from the “virtual” effective diameter (see 3.1.2).NOTE Also known as pitch diameter.3.1.2 virtual effective diametereffective dia
28、meter of an imaginary threadof perfectpitch and flank angle, having the full depth of flanks, but clear at the crests and roots, which would just assemble with the actual thread over the prescribed length of engagementNOTE The “virtual” effective diameter exceeds the effective diameter inthe case of
29、 an external thread, but is less than the effective diameter in the case of an internal thread by an amount corresponding to the combined diametral effects due to any errors in the pitch and/or the flank angles of the thread.3.2 SymbolsFor the purposes of this part of BS 919, the following symbols a
30、pply.NOTE These are largely repeated from BS 6528 for the convenience of users of this standard.C truncation on external threadD major diameter of internal threadD1minor diameter of internal threadD2effective diameter of internal thread (seeNote 2)d major diameter of external threadd1minor diameter
31、of external threadd2effective diameter of external thread (see Note 2)G1, G3and T1tolerance oneffective diameterG5and T3toleranceon effective diameter equivalent of angle errorG2, G4and T2tolerance on effective diameter equivalent of pitch and angle errorsG6, G7and G8combined tolerance on effectived
32、iameter and effectivediameter equivalent ofpitch and angle errorsH height of fundamental triangleM margin for wearP pitchR depth oftruncation BSI 2009 3BS 919-2:20074Design4.1 GeneralThe general dimensions of blanks suitable for both screw and plain gauges shall conform to BS 1044-1.4.2 F e a t h e
33、r e d g e sTo avoid featheredges on screw plugand ring gauges and setting plugs, the partial thread at both ends ofthe gauge shall be removed to a blunt start, except for:a) screw plug gauges and setting plugs in sizes below 0.150 inch and/or with external cone centres; andb) screw ring gauges inch
34、nominal sizeand smaller or with pitches of 20 threads per inch and finer and on all screw plug gauges and setting plugs withpitches of 28 threads per inch and finer, for which a 60 chamfer from the axis of the gauge is permitted in lieu of the removal of the partial thread. Not more than one complet
35、e turn of the thread shall be removed to the point where the full thread form is obtained.Ondouble lengthsettingplugs withpitches of 28 threads per inchandcoarser, where the truncated portion meets the full form portion, the feather edge shall be completelyremoved.4.3 Dirt clearance groovesWhen spec
36、ified by the purchaser, screw plug gauges shall haveadirtclearance groove cut axial to the thread to a depth slightly below the rootof the thread. Thisgroove shall be cut at the position where the thread commences at its full section as described in 4.2.4.4 Removal of sharp edgesAll sharp edges on t
37、he gauging portions and handles shall be removed.12- - - BSI 2009BS 919-2:200745Dispotn fgauetolrnc zes5.1 General GO screw gaugesThe tolerance zones for the effective diameter of General GO gauges shall be situated inside the corresponding zones of workpiece tolerance, as shown inFigure 1. (See Ann
38、ex B for notes on the conventional method of showing tolerance zones.) NOTE A small margin within the workpiece tolerance zone is provided for wear on GO screw plug gauges (the maximum metal limit), beyondwhich GO gauges ought not to be permitted to wear.GO gauges intended for checking Whitworth (cl
39、ose fit) and BSC (close class) classes of workpiece (see A.1) shall conform to 5.2.5.2 Reference GO gaugesThe Reference GO plug gauge limits and the Reference setting plug limits for effective diameter shall be disposed bilaterally about the maximum metal limits of the workpiece (low limit for inter
40、nal threads and high limit for external threads), as shown in Figure 1.Reference GO screwring gauges (solidor adjustable) andGO threadcalliper gauges shall be adjusted to size by fitting them to Reference setting plugs.NOTE 1 Such practice renders unnecessary any direct measurement of the diameter o
41、f the internal gauge.NOTE 2 Workpieces ought only to be rejected on final inspection where a screw gauge has failed the Reference plug gauge in the case of internal threads, or a ring gauge set to a Reference setting plug in the case of external threads.5.3 NOT GO screw gaugesThe tolerance zones (ef
42、fective diameter) for NOT GO effective diameter gauges shall be placed just outside the corresponding zones of workpiece tolerance, as shown in Figure 1. NOTE Wear causes NOT GO gauges to become gradually less accurate in the inspection of the workpieces.5.4 Setting plugsThe tolerance zones for the
43、effective diameters of both General and Reference setting plugs shall be as shown in Figure 1.NOTE Too much emphasis cannot be laid on the importance of gauge users exercising vigilance in the effect of wear upon the sizes of gauges.Adjustable screw ring and calliper gauges should be maintained with
44、intheir limits by resetting to their setting plugs at suitable intervals.screw P Q BSI 2009 5BS 919-2:2007Figure 1 Disposition of effective diameter tolerance zones for screwgaugesa) Plug gaugesb) Ring and calliper gaugesTolerance for external thread (bolt)High limitReferencesetting plugT2T1G8T3T1Se
45、tting plug for adjustable NOT GO ring or calliperGeneral GO gauge (ring or calliper)Setting plug for adjustable GO ring or calliperNOT GO gauge (calliper or ring)Low limitG7G6Directionof wear of gaugesTolerance for internal thread (nut)High limitNOT GO plug gaugeG5G1G2G1G4G3Reference plug gaugeDirec
46、tion of wear of gaugesGeneral GO plug guageMLow limitQP BSI 2009BS 919-2:200766Gauges forintal screwthads6.1 GO screw plug gauges6.1.1 Limits of toleranceThe limits of tolerance for General GO screw plug gauges shall be asspecified in Table 1.The limits of tolerance for Reference GO screw plug gauge
47、s (and GO screw plug gauges for Close fits) shall be as specified in Table 2.NOTE Table 1 and Table 2 show the effective diameter tolerance in two independent parts, one for the effective diameter and the other for the effective diameter equivalent of the errors present in the pitch and angle of gau
48、ges. This method of specifying the tolerance is adopted to ensure a reasonable life for the gauges. Tables showing the effective diameter equivalent of errors in pitch and angle are given in Annex C.6.1.2 Form and length of threadGO screw plug gauges shall have the appropriate form of thread as show
49、n in Figure 2.The length of threadfor normal purposes shall be determined by the length given in BS 1044-1, unless the length of engagement of the components is exceptionally long, in which case the length of the gauge can be increased.6.2 NOT GO effective diameter screw plug gauges6.2.1 Limits of toleranceThe limits of tolerance for NOT GO effective diameter screw plug gauges for all classes of workpieces shall be as shown in Table 3.NOTE 1 As in the case of GO screw plug gauges, the effective diame
