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 1Gauge blocks manufactured to imperial specification Part 2: AccessoriesBS 4311-2:2009BS 4311-2:2009 BRITISH STAND
2、ARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the document was last issued. BSI 2009 ISBN 978 0 580 65348 3ICS 17.040.30The following BSI references relate to the work on this standard: Committee reference TDW/4 Draft for comment 09/3019311
3、7 DCPublication historyFirst published February 1994Second (present) edition, June 2009Amendments issued since publicationDate Text affected BRITISH STANDARD BSI 2009 iBS 4311-2:2009ContentsForeword ii0 Introduction 11 Scope 12 Normative references 13 Terms and definitions 24 Material for accessorie
4、s, other than the guide plates of holders 35 Type A measuring jaws 36 Type B measuring jaws 57 Scriber point and centre point 68 Base 79 Holders 810 Marking 911 Case 912 Protection against adverse climatic conditions 9AnnexesAnnex A (informative) Notes on the use of gauge block accessories 10Annex B
5、 (informative) Accessories 10Bibliography 11List of figuresFigure 1 Examples of assemblies of gauge block accessories 2Figure 2 Type A jaws 3Figure 3 Type B jaws 5Figure 4 Scriber point 6Figure 5 Centre point 7Figure 6 Detail of holder 8List of tablesTable 1 Dimensions of Type A jaws 4Summary of pag
6、esThis document comprises a front cover, an inside front cover, pages i to ii, pages 1 to 12, an inside back cover and a back cover.BS 4311-2:2009ii BSI 2009BRITISH STANDARDForewordPublishing informationThis part of BS 4311-2 is published by BSI and came into effect on 30 June 2009. It was prepared
7、by Technical Committee TDW/4, Technical product realization. A list of organizations represented on this committee can be obtained on request to its secretary. SupersessionBS 4311-2:2009 supersedes BS 4311-2:1994, which was withdrawn with the publication of BS 4311-1:2007+C1:2009.Relationship with o
8、ther documentsBS 4311-2:2009 is associated with BS EN ISO 3650:1999, which specifies the most important design and metrological characteristics of gauge blocks with a rectangular cross-section and a nominal length lnranging from 0,5 mm to 1 000 mm. BS 4311-2:2009 is also associated with BS 4311-1:20
9、07+C1:2009, which addresses the requirements for the ongoing support for gauge blocks manufactured to the imperial system.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Its requirements are expressed in sentences in which the principal auxiliary
10、 verb is “shall”.Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.A comma, rather than a full point, has been used as the decimal indicator throughout this British Standard in order to align it with the Geometri
11、cal Product Specifications referenced in Clause 2. Care should be taken when using this publication in conjunction with other British Standards.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its c
12、orrect application.Compliance with a British Standard cannot confer immunity from legal obligations.BRITISH STANDARD BSI 2009 1BS 4311-2:20090 IntroductionThe use of gauge blocks for measuring and for calibrating measuring instruments can be extended by accessories of the types specified in this sta
13、ndard. For instance pairs of Type A and Type B jaws are specified which, when combined with gauge blocks, form an external or an internal calliper.Other accessories specified in this standard are a robust base that can be used to convert a stack of wrung gauge blocks into a height gauge; and a centr
14、e point and an edged tool for scribing arcs of precise radius. The various items are provided with wringing surfaces suitable for wringing to gauge blocks, and holders are available for supporting the wrung gauge block stacks when in use.The accuracy of measurements obtained when using the accessori
15、es is influenced by the manner of their use, e.g. reduction of flexure in calliper jaws, better flatness of the datum surface on which the base is located, and avoidance of local wear, particularly on the scribing tool and the Type A jaws, are all ways of improving the accuracy which can be achieved
16、.1 ScopeThis British Standard specifies requirements for accessories intended for use with metric and inch gauge blocks conforming to BS EN ISO 3650 and BS 4311-1:2007+C1:2009, and includes two types of measuring jaw (Type A and Type B), scriber points and centre points, bases and holders. Requireme
17、nts for general dimensions and the form, material, surface finish and accuracy of various features are specified.Examples of typical assemblies of accessories are shown in Figure 1 and notes on their use are given in Annex A.Annex B gives details of other items which may be used with gauge blocks an
18、d accessories.NOTE Type B jaws, scriber points, centre points and holders specified for metric gauge blocks are fully compatible with gauge blocks in inch units.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only
19、 the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. BS 4311-1:2007+C1:2009, Gauge blocks manufactured to imperial specification Part 1: Specification and validationBS EN ISO 3650, Geometrical product specifications (GP
20、S) Length standards Gauge blocksBS EN ISO 6507-1, Metallic materials Vickers hardness test Part 1: Test methodBS 4311-2:20092 BSI 2009BRITISH STANDARD3 Terms and definitionsFor the purposes of this part of BS 4311, the terms and definitions given in BS EN ISO 3650 and BS 4311-1 apply.Figure 1 Exampl
21、es of assemblies of gauge block accessoriesKey1 Gauge block(s)2 Holder3 Measuring jaws (Type B)4 Measuring jaws (Type A)5 Scriber point6 Centre point7 Base8 Platform9 Toolmakers flat or surface plate (not an accessory)BRITISH STANDARD BSI 2009 3BS 4311-2:20094 Material for accessories, other than th
22、e guide plates of holdersAccessories shall be of high grade steel or other wear-resistant material equivalent to that of steel, having a hardness of not less than 750 HV. When steel is used the accessories shall be hardened to not less than 750 HV when tested in accordance with BS EN ISO 6507-1.The
23、accessories shall be heat-treated to stabilize the material.NOTE 1 The guide plates of holders can be of steel or other wearresistant material equivalent to that of steel having a hardness of not less than 250 HV.NOTE 2 Approximate equivalent hardness values for other hardness scales are specified i
24、n BS EN ISO 18265.5 Type A measuring jaws5.1 GeneralThe form and dimensions of Type A measuring jaws shall be as specified in Figure 2 and Table 1.NOTE These jaws are usually supplied in pairs for internal or external measurements.Figure 2 Type A jawsDimensions in millimetresKey1 Wringing face2 End
25、elevation enlargedBS 4311-2:20094 BSI 2009BRITISH STANDARDTable 1 Dimensions of Type A jawsRecommended nominal dimension (unit of length)Approximate dimensionsinch mm mmA A B C D E F0,1 2 7,5 40 6 34 1,0 (rad. or undercut)0,2 5 7,5 45 15 30 1,50,25 7,5 50 20 30 1,5 8 12,5 50 20 30 1,5 12,5 12,5 75 4
26、5 30 205.2 Finish and accuracyThe wringing faces shall be finished by high grade lapping and shall have a deviation from flatness not greater than 0,000 3 mm within any 35 mm length.For each jaw, dimension A (Table 1) shall be a nominal length 00 001+ ,mm. Angle (Figure 2) shall be 90 100 .Additiona
27、lly, when the pair of jaws is wrung over an interposed gauge block having a nominal length approximately equal to dimension A and aligned along one side, the maximum error in the overall length shall be not greater than + 0,001 mm.NOTE 1 In manufacture this tolerance may be achieved by positioning t
28、he centre for the radius R midway between the side faces to within 0,025 mm.NOTE 2 These jaws should not be used for the accurate measurement of internal diameters less than 3A.BRITISH STANDARD BSI 2009 5BS 4311-2:20096 Type B measuring jaws6.1 GeneralThe form and dimensions of Type B measuring jaws
29、 shall be as specified in Figure 3.NOTE These jaws are usually supplied in pairs for external measurements. 6.2 Finish and accuracyThe wringing faces shall be finished by high grade lapping and shall have a deviation from flatness not greater than 0,000 3 mm within any 35 mm length.Angle shall be 90
30、 100 .Figure 3 Type B jawsDimensions in millimetresKey1 Wringing face2 End elevation enlargedBS 4311-2:20096 BSI 2009BRITISH STANDARD7 Scriber point and centre point7.1 GeneralThe form and dimensions of the scriber point shall be as specified in Figure 4.The form and dimensions of the centre point s
31、hall be as specified in Figure 5.NOTE These items are usually supplied together for the scribing of arcs.Figure 4 Scriber pointDimensions in millimetresKey1 Radius 0,05 with sharp edge for scribing2 Wringing face7.2 Finish and accuracyThe wringing faces shall be finished by high grade lapping and th
32、eir deviation from flatness shall be not greater than 0,000 3 mm within any 35 mm length.Angle shall be 90 100 .The deviation of the centre point from the plane of the wringing face shall be not greater than 0,01 mm.A circle of a desired nominal diameter can be scribed when the scriber point and cen
33、tre point are used together with a stack of gauge blocks wrung between these two accessories. The nominal diameter of the circle shall be equal to twice the sum of the nominal lengths BRITISH STANDARD BSI 2009 7BS 4311-2:2009of the gauge blocks. The deviation of the scribed diameter from its nominal
34、 value shall be not greater than 0,025 mm, with the diameter measured between the inside edges of the scribed lines.Figure 5 Centre pointDimensions in millimetresKey1 Wringing face2 End elevation enlarged8 Base8.1 GeneralThe base shall be designed for use in combination with wrung gauge blocks to pr
35、ovide a nominal length over a datum surface, designated a platform, in contact with the underside of the base.The base, including the platform to which the gauge blocks are wrung, shall be designed to remain stable when used with a holder capable of supporting a wrung combination of gauge blocks up
36、to a nominal length of 300 mm.Means shall be provided for attaching the holder so that the combination of gauge blocks is perpendicular to the datum surface.BS 4311-2:20098 BSI 2009BRITISH STANDARDThe underside of the base shall be relieved and an air vent provided. The sides shall be relieved to fo
37、rm convenient finger grips.The platform shall have a length of not less than 35 mm.The platform shall have a width of 9 0 070 5,mm.8.2 Finish and accuracyThe underside of the base and the platform upon which gauge block combinations are to be wrung shall be finished by high grade lapping to within t
38、he following tolerances.a) The deviation from flatness of the underside of the base shall be not greater than 0,001 mm and the base shall not rock.b) The deviation from flatness of the platform shall be not greater than 0,000 3 mm.c) The deviation from parallel of the platform shall be not greater t
39、han 0,000 3 mm with the underside of the base as the datum plane.d) The deviation from the nominal height of the measured length to the platform from the underside of the base shall be not greater than 0,000 8 mm.9 HoldersThe holders shall be capable of accommodating wrung combinations of gauge bloc
40、ks and accessories, and of preventing relative movements of items while they are in use.The holder shall incorporate a swivel joint (see Figure 6) between the sliding block and the clamping screw to ensure an even pressure on the combination.The surfaces of the sliding and fixed blocks against which
41、 the combination abuts shall be finished by lapping and the centres of these surfaces shall be relieved (see Figure 6).The distance between the side plates shall be 9 00 1+ ,mm.Figure 6 Detail of holderKey1 Swivel joint2 Centre portion relieved3 Clamping screw4 Sliding blockBRITISH STANDARD BSI 2009
42、 9BS 4311-2:200910 MarkingEach accessory shall be marked with the manufacturers name, initials or trademark.Type A jaws and their bases shall be marked with the nominal size.11 CaseEach set of accessories shall be supplied in a case, with a separate compartment for each accessory.The case shall have
43、 a hinged lid and the means to retain the lid in its closed position.The case shall be designed so that, when the lid is closed, the accessories cannot become displaced or their lapped faces become damaged by contact with the surfaces of the compartments.The joint between the lid and the body of the
44、 case shall be close fitting and prevent the ingress of dust (e.g. opposed faces rebated or having a fillet and groove).12 Protection against adverse climatic conditionsAll surfaces of the accessories shall be protected against adverse climatic conditions with a suitable protective preparation to pr
45、event corrosion.1)1)Guidance on packaging is given in BS 1133-19.BS 4311-2:200910 BSI 2009BRITISH STANDARDAnnex A (informative) Notes on the use of gauge block accessoriesA.1 Type A and Type B jawsWhen wringing the jaws with gauge blocks the combination should be aligned by bringing the correspondin
46、g side faces of the items into contact with a surface plate. The projection of the jaws beyond the gauge blocks should be minimized to avoid loss of accuracy through springing of the tips of the jaws.A.2 Type A jawsType A jaws wear most at the leading end: a sign of wear is an abraded line along the
47、 cylindrical surface.A.3 Scriber and centre pointsIn all manipulation, care should be taken to protect both points against burrs or blunting. When assembling points with a combination of gauge blocks, it is advisable to align the assembly along one side against a surface plate. Furthermore, the cent
48、re lines of scribers and centre points should be kept parallel with the axis of the gauge blocks.The scribing of arcs is facilitated if the sample is polished beforehand and if it can be rotated beneath the scribing assembly. If thick lines result there is uncertainty as to the true location of the
49、marks since the scratch could be asymmetrical, and the innermost edge, from which measurements should be taken, could be irregular in outline.The scriber will wear with use and its scribing edge should be checked by inspection under optical magnification. Where a travelling microscope is available, the user may prefer to scribe arcs of nominal radius and measure the diameter of the scribed circle; the interposed gauge blocks may then be adjusted if necessary, and arcs rescribed.Rectification o
