1、BRITISH STANDARD BS3123:1959 Specification for Spring calipers and spring dividersBS3123:1959 This British Standard, having been approved by the MechanicalEngineering IndustryStandards Committee and endorsed by the Chairman ofthe Engineering Divisional Council, was published under theauthority of th
2、e General Council on 17June1959 BSI 09-1999 The following BSI references relate to the work on this standard: Committee references MEE/120, MEE/120/8 Draft for comment CY(MEE)8937 ISBN 0 580 35308 7 Co-operating organizations The Mechanical Engineering Industry Standards Committee, under whose super
3、vision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty* High Commission of India Air Ministry Institute of Marine Engineers Associated Offices Technical Committee Institute of Petroleum A
4、ssociation of Consulting Engineers Institution of Civil Engineers (Incorporated) Institution of Gas Engineers* British Chemical Plant Manufacturers Institution of Heating and Ventilating Association Engineers British Compressed Air Society Institution of Mechanical Engineers British Electrical and A
5、llied Manufacturers Institution of Mechanical Engineers Association (Automobile Division) British Engineers Association* Institution of Production Engineers* British Gear Manufacturers Association Locomotive and Allied Manufacturers British Internal Combustion Engine Association of Great Britain* Ma
6、nufacturers Association Machine Tool Trades Association British Iron and Steel Federation Ministry of Labour and National Service British Railways, The British Transport (Factory Inspectorate) Commission* Ministry of Power Crown Agents for Oversea Governments and Ministry of Supply* Administrations
7、Ministry of Transport and Civil Aviation* D.S.I.R. National Engineering Laboratory Ministry of Works Electricity Council, the Generating Board and National Coal Board* the Area Boards in England and Wales National Physical Laboratory (D.S.I.R.) Engineering Equipment Users Association* Radio Industry
8、 Council Gas Council* War Office The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the Committee entrusted with the preparation of this standard: Association of UnitedKingdom Pli
9、er National Association of Tool Dealers Manufacturers National Federation of Building Trades Edge Tool Manufacturers Association Employers Engineers and Allied Hand Tool Makers National Union of Furniture Trades Association Operatives Federation of British Hand Tool Post Office Manufacturers Saw Tra
10、des Association Institution of Engineering Inspection Society of British Aircraft Constructors J.E.S.C. Sub-committee on Hand Tools Society of Motor Manufacturers and Traders Light Edge Tool and Allied Trades Co-opted manufacturers Association London Transport Executive, The British Transport Commis
11、sion Amendments issued since publication Amd. No. Date CommentsBS3123:1959 BSI 09-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Section 1. General 1 Scope 1 2 Nomenclature 1 Section 2. Manufacture 3 Material 1 4 Heat treatment and hardness 1 5 Dimensions and capaciti
12、es 1 6 Manufacture and assembly 1 7 Finish 3 8 Marking 3 Section 3. Testing 4 Figure 1 Nomenclature for spring calipers and spring dividers 2 Figure 2 3BS3123:1959 ii BSI 09-1999 Foreword This standard makes reference to the following British Standards: BS350, Conversion factors and tables. BS860, A
13、pproximate comparison of hardness scales. BS970, Wrought steels. This British Standard has been prepared under the authority of the Mechanical Engineering Standards Committee and forms one of a series covering a wide range of hand tools. Provision is made for three types of spring calipers and sprin
14、g dividers, thus recognizing the preferences of individual craftsmen. The range of nominal sizes listed against each type covers those in common demand at the present time. Components of spring calipers and dividers are rarely supplied as spares and therefore detailed consideration has only been giv
15、en to those parts which directly affect the quality, functioning and life of the complete instrument. In compiling the specification care has been taken to ensure that the craftsman has a highly satisfactory tool at his command, recognizing at the same time that further design and production develop
16、ment of the instruments should not be unnecessarily restricted. The dimensions, tolerances and other figures in the specification are given in the British system, which is to be regarded as the standard. The tools are, however, exported to all parts of the world and to assist those using the metric
17、system a conversion table is included. The metric figures are approximate, and more accurate conversions should be based on the tables in BS350. 1) A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct
18、application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright dat
19、e) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) BS350, “Conversion factors and tables”.BS3123:1959 BSI 09-1999 1 Section 1. General 1 Scope This British Standard relates to the materials, manufacture and testing of the followin
20、g types of spring calipers and spring dividers. Type A: Instruments with rectangular section legs. Type B: Instruments with squared section legs. Type C: Instruments with round section legs. 2 Nomenclature For the purpose of this British Standard the nomenclature given in Figure 1 applies. Section 2
21、. Manufacture 3 Material The components of spring calipers and spring dividers shall be manufactured from the materials listed below: a) Legs: From carbon spring steel conforming to BS970 2)En42B. b) Spring: From carbon spring steel conforming to BS970 2)En42D. c) Other components: From free cutting
22、 steel conforming to BS970 2)En1B. 4 Heat treatment and hardness a) Legs. The working ends of the divider legs shall be suitably heat-treated for a distance of 3 / 8in. from the extreme tips, to give a hardness that will enable the instrument to pass the test requirements of Clause9 a) ii). b) Sprin
23、g. The spring shall be hardened and tempered to give a hardness reading within the range470/520HV (Diamond Pyramid Scale) using a5kg load. The equivalent values on other hardness scales may be used in accordance with BS860 3) . 5 Dimensions and capacities The dimensions and capacities of spring cali
24、pers and spring dividers shall be as follows: a) Nominal size. The nominal size shall be the distance between the centre of the roller and the extreme working ends of the legs. (See Figure 1.) The nominal sizes of Types A, B and C instruments shall be those given in Figure 2. b) Capacity. The maximu
25、m capacity shall be not less than the nominal size of the instrument. Internal spring calipers shall be capable of effective measurement in the following minimum sizes of bore: c) Dimensions of leg sections. The dimensions of the leg sections of spring calipers and spring dividers shall be in accord
26、ance with Figure 2. 6 Manufacture and assembly Components of spring calipers and spring dividers shall be manufactured and assembled in accordance with the following requirements to ensure that smooth adjustment and efficient operation is achieved and maintained. a) The instruments shall be adjusted
27、 by means of either a knurled solid nut or a knurled quick-action release nut operating on a finely threaded adjusting screw. The type of nut in relation to the class of instrument shall be as follows: Type A. Either solid nut or quick-action release nut. Type B. Quick-action release nut. Type C. So
28、lid nut. b) The working ends of the legs of each instrument shall be identical in shape, with the contact points equally distant from the fulcrum. Each pair of calipers shall have the measuring ends of the legs so shaped that all sizes within its capacity may be readily transferred from measuring sc
29、ales or gauges. 2) BS 970, “Wrought steels”. 3) BS 860, “Approximate comparison of hardness scales”. Type A3 in.nominal size 3 / 8 in. 4in. and5in. nominal sizes 7 / 16in. 6in. nominal size 9 / 16in. 8in. nominal size 11 / 16in. 10in. nominal size 13 / 16in. 12in. nominal size 15 / 16in. Types B and
30、 C (where applicable) 2in. and3in. nominal sizes 11 / 32in. 4in.5in. and6in. nominal sizes 3 / 8in.BS 3123:1959 2 BSI 09-1999 NOTEThe illustrations are diagrammatic only. Figure 1 Nomenclature for spring calipers and spring dividersBS3123:1959 BSI 09-1999 3 c) In order to maintain alignment of the w
31、orking ends, the tops of the legs shall be located in a flanged fulcrum roller and held in position by a spring. The spring, shall provide sufficient tension to hold the legs rigid at all points of adjustment. d) Suitable means shall be employed to minimize friction between the adjusting nut and the
32、 leg of the instrument either by use of a separate washer under the nut, or by a washer-facing produced on the nut. e) One end of the adjusting screw shall be securely hinged to a leg of the instrument, and a steel ball shall be positively fixed to the remaining free end of the screw for the purpose
33、 of retaining the adjusting nut. f) The peg used for rotating the dividers between thumb and finger shall be knurled and located centrally in the spring. It shall be positively and securely fixed so that it will not turn independently of the remainder of the instrument. 7 Finish The component parts
34、of spring calipers and spring dividers shall have a smooth bright finish, or, by agreement between purchaser and manufacturer, parts may be rust-proofed or coloured by chemical and/or thermal processes. 8 Marking Each instrument shall be clearly and indelibly marked with the number of this British S
35、tandard, and with some means of positively identifying the source of manufacture, such as the manufacturers name or trade mark. Form and dimensions of leg sections. Spring calipers andspringdividers Type A: Rectangular section legs Nominal size of instrument Dimensions of leg section at“A A” (Figure
36、 1) W T r 3in. 4in.,5in. 6in. 8in.,10in.,12in. in. 1 / 4 5 / 16 3 / 8 7 / 16 in. 7 / 64 1 / 8 1 / 8 5 / 32 in. 5 / 64 5 / 64 5 / 64 1 / 8 Type B: Squared section legs Nominal size of instrument Dimensions of leg section at“A A” (Figure 1) W T r 3in. 4in. 5in. 6in. in. 7 / 3215 / 64 1 / 4 9 / 32 in.
37、1 / 4 9 / 32 5 / 16 11 / 32 in. 13 / 3227 / 64 7 / 16 15 / 32 Type C: Round section legs Nominal size of instrument Dimension of leg section at “A A” (Figure 1) Diameter 2in.,3in. 4in.,5in. 6in. in. 0.200 0.250 0.281 Figure 2 BS3123:1959 4 BSI 09-1999 Section 3. Testing Each instrument shall be capa
38、ble of passing the following tests: a) Functional tests i) Spring calipers and spring dividers. Each instrument shall work smoothly and retain its required size when adjusted to three test pieces or gauges, the sizes of which shall be relative to the approximate lower, middle and upper registers of
39、the particular instrument range. ii) Spring dividers. Each instrument shall be capable of scribing a clearly defined line across the face of a test block, the face of which shall be hardened within the range620/660HV (Diamond Pyramid Scale) using a30kg load. Following this test the working ends shal
40、l still be sharp and visual examination shall reveal no sign of damage or failure. b) Joint and bend test. Spring dividers. With the divider legs opened to a distance of 1 / 4 in., one leg shall be clamped securely in a vice at a point approximately 1 / 2 in. from the fulcrum, so that the two legs a
41、re in a horizontal plane. A test load of10lb(4.54kg) shall then be gradually applied by suspension from the free leg as close to the working end as is practicable. On removal of the load the joint of the instrument shall not have been displaced nor shall the legs show any sign of permanent set. Tabl
42、e of metric equivalents 1 2 3 4 5 6 7 8 Inches Millimetres Inches Millimetres Inches Millimetres Inches Millimetres in. 1 / 64 1 / 32 3 / 64 1 / 16 5 / 64 3 / 32 7 / 64 1 / 8 9 / 64 5 / 32 3 / 16 7 / 32 mm 0.397 0.793 1.191 1.587 1.984 2.38 2.78 3.17 3.57 3.97 4.76 5.56 in. 1 / 4 9 / 32 5 / 16 11 /
43、32 3 / 8 13 / 32 7 / 16 15 / 32 1 / 2 17 / 32 9 / 16 19 / 32 mm 6.35 7.1 7.9 8.7 9.5 10.3 11.1 11.9 12.7 13.5 14.3 15.1 in. 5 / 8 21 / 32 11 / 16 23 / 32 3 / 4 25 / 32 13 / 16 27 / 32 7 / 8 29 / 32 15 / 16 31 / 32 mm 15.9 16.7 17.5 18.3 19.0 19.8 20.6 21.4 22.2 23.0 23.8 24.6 in. 1 2 3 4 5 6 7 8 9 1
44、0 11 12 mm 25.4 50.8 76.2 101.6 127.0 152.4 178 203 229 254 279 305 Conversion factor:1in.=25.4mm. For more accurate conversions, see BS350, “Conversion factors and tables”.BS3123:1959 BSI 09-1999 British Standards The following are available on application: YEARBOOK SECTIONAL LISTS. Gratis Acoustic
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48、ards 15s.BS3123:1959 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions
49、BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service called PLUS which e
