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1、BRITISH STANDARD BS 907:1965 Specification for Dial gauges for linear measurement BS 907:1965 This British Standard, having been approved by the mechanical engineering industry standards committee and endorsed by the chairman of the engineering divisional council, was published under the authority,
2、of the general council on 29th November, 1965. BSI 12-1998 First published, June, 1940. First revision, January, 1954. Second revision, November, 1965. The following BSI references relate to the work on this standard: Committee reference MEE/59 Draft for comment D64/8394 ISBN 0 580 305961 Co-operati
3、ng organizations The Mechanical Engineering Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Associated Offices Technical Committee Association
4、of Consulting Engineers Association of Mining Electrical and Mechanical Engineers Board of Trade British Chemical Plant Manufacturers Association British Compressed Air Society British Electrical and Allied Manufacturers Association British Gear Manufacturers Association British Internal Combustion
5、Engine Manufacturers Association British Iron and Steel Federation British Mechanical Engineering Federation British Railways Board Crown Agents for Oversea Governments and Administrations Electricity Council, The Generating Board and the Area Boards in England and Wales Engineering Equipment Users
6、Association Gas Council Institute of Marine Engineers Institution of Civil Engineers Institution of Gas Engineers Institution of Heating and Ventilating Engineers Institution of Mechanical Engineers Institution of Mechanical Engineers (Automobile Division) Institution of Production Engineers Locomot
7、ive and Allied Manufacturers Association of Great Britain London Transport Board Machine Tool Trades Association Ministry of Defence, Army Department Ministry of Defence, Navy Department Ministry of Labour (H.M. Factory Inspectorate) Ministry of Power Ministry of Public Building and Works Ministry o
8、f TechnologyNational Engineering Laboratory Ministry of Transport National Coal Board National Physical Laboratory (Ministry of Technology) Radio Industry Council Royal Institute of British Architects Amendments issued since publication Amd. No.DateComments BS 907:1965 BSI 12-1998i Contents Page Co-
9、operating organizationsInside front cover Forewordii 1Scope1 2Nomenclature and definitions1 3General features of design1 4Recommended dimensions2 5Dial2 6Pointer2 7Revolution counter3 8Plunge 3 9Contact point3 10Repeatability of reading4 11Packing4 12Marking4 Appendix A Recommended dimensions for di
10、al gauges6 Appendix B Notes on methods of testing dial gauges7 Appendix C Notes on the care and use of dial gauges10 Figure 1 Nomenclature of dial gauges1 Figure 2 00001 in, 0001 in or 001 mm dial2 Figure 3 00005 in dial2 Figure 4 Free position of pointer3 Figure 5 Dial gauge dimensions6 Figure 6 Ca
11、libration curve of a dial gauge illustrating periodic error9 Table 1 Limits of error for dials with scale divisions of 0001 in and 00005 in4 Table 2 Limits of error for dials with scale divisions of 00001 in4 Table 3 Limits of error for dials with scale divisions of 001 mm4 Table 4 Error of reading
12、of dial gauge given in units of 00001 in8 BS 907:1965 ii BSI 12-1998 Foreword In order to keep abreast of progress in the industries concerned, British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due course brought to the notice of the committees
13、charged with the revision of the standards to which they refer. A complete list of British Standards, numbering over 9,000, fully indexed and with a note of the contents of each, will be found in the BSI Catalogue which may be purchased from BSI Sales Department. The Catalogue may be consulted in ma
14、ny public libraries and similar institutions. This British Standard for dial gauges for linear measurement has been prepared under the authority of the Mechanical Engineering Industry Standards Committee. It forms one of a series of standards for engineers precision measuring equipment originated by
15、 a request from the Institution of Production Engineers and prepared with the co-operation of manufacturers and in close collaboration with the National Physical Laboratory. The standard was first issued in 1940 and when it was revised in 1954 provision for the back plunger type of dial gauge was in
16、corporated. Subsequent experience has shown that requirements for this type of gauge cannot always be assimilated to those for dial gauges with the plunger movement parallel to the plane of the dial and it has accordingly been deleted from this edition. Since the publication of the 1954 edition, an
17、ISO Recommendation for dial gauges has been drafted and the Committee have taken note of its provisions in preparing this revision. A British Standard does not purport to include all the necessary provisions of a contract.Users of British Standards are responsible for their correct application. Comp
18、liance 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, pages i and ii, pages 1 to 10 and a back cover. This standard has been updated (see copyright date) and may have had amendments inc
19、orporated. This will be indicated in the amendment table on the inside front cover. BS 907:1965 BSI 12-19981 1 Scope This British Standard relates to dial gauges with the plunger movement parallel to the plane of the dial. It applies to gauges having dial diameters from 17/8 in to 21/2 in, as measur
20、ed from the outside of the scale marks, and scale divisions of 0001 in (sometimes sub-divided into half divisions of 00005 in, in which case they are commonly designated “00005 in gauges”), 00001 in or 001 mm. Recommended dimensions for dial gauges are given in Appendix A (Figure 5) and notes on met
21、hods of testing and on the care and use of dial gauges are given in Appendices B and C respectively. 2 Nomenclature and definitions For the purposes of this British Standard the nomenclature is as given in Figure 1 and the following definitions apply: scale mark one of the marks constituting a scale
22、 minimum scale value the smallest value of the measured quantity which the scale is graduated to indicate scale division a part of a scale delimited by two adjacent scale marks discrimination the sensitiveness of an instrument, the smallest change in the quantity measured which produces a perceptibl
23、e movement of the pointer repeatability the reproducibility of the readings of an instrument when a series of tests is carried out in a short interval of time under fixed conditions of use limits of error the positive and/or negative values of the errors which must not be exceeded under test 3 Gener
24、al features of design The general design and workmanship shall be such as to ensure that the performance of the gauge meets the requirements of this standard under all ordinary methods of operation. The mechanism shall incorporate some means to eliminate backlash. The design and rigidity of the case
25、 shall be such that the freedom of movement of the mechanism is not impaired by the tightening of the screws used for attaching the back or by the clamping of the stem of the instrument, provided that such clamping is carried out in an appropriate manner (see Appendix C, “Clamping”). The dial cover
26、(or crystal) shall be of durable material which will retain its transparency without undue discolouration and both dial and case shall be dust proof. Figure 1 Nomenclature of dial gauges BS 907:1965 2 BSI 12-1998 Each gauge shall be provided with a satisfactory means of setting to zero. If this is a
27、chieved by rotation of the bezel then a clamping screw may or may not be provided, but care shall be taken to ensure that the setting is maintained on those which have no means of locking. Back lug fixings may be integral with the gauge or may be removable but shall in either case be square or paral
28、lel to the measuring axis of the instrument within 0006 in per inch in the design position. It is desirable that gauges shall be fitted with stainless steel plungers and hardened or stainless steel pinions. NOTEThe ranges of movement of the plunger vary with the make and type of gauge, and if the pu
29、rchaser has any particular requirements in respect of this range of movement, he should state them in his enquiry and order. 4 Recommended dimensions It is recommended that all new designs of gauges are made to the dimensions given in Appendix A and that, as opportunity offers, existing designs are
30、modified in accordance with them. 5 Dial Inch dials shall be graduated in minimum scale values of 00001 in, 00005 in or 0001 in and metric dials shall be graduated in minimum scale values of 001 mm. The minimum scale value shall be marked on all dials. The scale shall be marked with clear lines on a
31、 suitable background so as to be easily read. The thickness of the scale marks shall be uniform and shall not be less than 0006 in or more than 0010 in. Every tenth scale mark shall be indicated by a longer line and shall be numbered. Every fifth scale mark (except on 00005 in dial gauges) shall be
32、indicated by a line slightly less in length. 00005 in dial gauges shall have alternate scale divisions indicated by a shorter line. It is recommended that the length of the visible portion of the scale marks indicating each scale division should be approximately equal to the width of that division a
33、s shown in Figure 2 and Figure 3. 6 Pointer The pointer shall move in a clockwise direction when the plunger is pressed in. The pointer shall be attached to its spindle in such a manner as to ensure that there will be no relative movement between them when the spindle is subjected to rapid accelerat
34、ion or deceleration, as, for example, in the event of the plunger being suddenly released and its motion arrested by a fixed stop. The length of the pointer shall be such that its tip lies approximately over the centre of the length of the shortest scale marks. The thickness of that portion of the p
35、ointer immediately over the scale shall not exceed one-fifth of the width of one scale division and should preferably be of approximately the same thickness as the scale mark. To reduce parallax errors in use the pointer tip shall be as close to the scale as possible. When the plunger is in the posi
36、tion of rest and the zero mark on the dial is in the 12 oclock position, the pointer shall lie between the 9 oclock and 11 oclock positions (see Figure 4). Figure 2 00001 in, 0001 in or 001 mm dial Figure 3 00005 in dial BS 907:1965 BSI 12-19983 7 Revolution counter When a revolution counter is prov
37、ided, its pointer shall correctly indicate the appropriate division on its scale when the instrument pointer is at 12 oclock on each of its revolutions and shall preferably move in the same direction as the instrument pointer. 8 Plunger The plunger shall move freely in its bush, any shake, including
38、 rotational shake, being insufficient to affect the indication of the instrument by more than the thickness of a scale mark. For most purposes the force required to operate a dial gauge should be as light as possible. It should be measured with the gauge in the vertical position and with the plunger
39、 going in. It is recommended that the working force on dial gauges, other than 00001 in gauges, should be of the order of 2 oz at the beginning of the movement and any increase in force should not exceed 1/2 oz for each successive 0.1 in movement. If lighter or heavier working forces are required on
40、 0001 in, 00005 in and 001 mm gauges they should be specified by the purchaser. On 00001 in gauges with a travel up to 025 in the working force at any position of the plunger shall not exceed 6 oz. On 00001 in gauges with a travel greater than 025 in and up to and including 05 in, the working force
41、shall not exceed 8 oz. On 00001 in gauges with a travel greater than 05 in, the working force shall be the subject of agreement between manufacturer and purchaser. 9 Contact point The contact point shall have as large a radius as practicable and shall be readily removable from the plunger for the pu
42、rpose of replacement or the substitution of a contact point of different form. NOTE 1Dial gauges are normally supplied with a hardened spherically formed point. If some other form of point is required, this should be specified by the purchaser. (See Appendix C, Contact points.) NOTE 2It is recommend
43、ed that in all new designs of gauges the dimensions of the threads for the attachment of the contact point shall be in accordance with those given in Appendix A, Figure 5. Figure 4 Free position of pointer BS 907:1965 4 BSI 12-1998 10 Performance a. General. All measurements of the accuracy of perfo
44、rmance specified in this clause shall be referred to the standard reference temperature of 20 C. b. Repeatability of reading. The gauge shall repeat its readings under all ordinary methods of operation to within 00002 in on 0001 in and 00005 in gauges, 0000 02 in on 00001 in gauges and 0002 mm on me
45、tric gauges. (See Appendix C. Use of plunger lifting lever.) c. Discrimination. 0001 in and 00005 in gauges shall be capable of indicating small gradual changes of the order of 0001 inch in either direction of the plunger to within 00003 in. The 00001 in gauge shall be capable of indicating small gr
46、adual changes of the order of 00002 inch in either direction of the plunger to within 0000 04 in. The metric gauge shall be capable of indicating small gradual changes of the order of 0025 mm in either direction of the plunger to within 0003 mm. The degree of discrimination specified above shall be
47、achieved without resort to tapping the gauge. d. Limits of error. Errors permissible in dial gauges differ according to the type of instrument and the magnitude of the difference measured. Table 1 to Table 3 give the errors allowed for different types of dial gauges in common use. Since dial gauges
48、are primarily intended for the measuring of small differences in dimensions, it will be noted that the same order of accuracy of the instrument when used for the measuring of small differences in dimensions will not be realized when larger differences are concerned. The error over an interval of rea
49、ding may be either plus or minus and the permissible errors shall not be exceeded for either direction of movement of the pointer. Calibration shall take place from the first 12 oclock position of the pointer (see Figure 4) unless otherwise specified by the purchaser. The permissible errors stated in Table 1 to Table 3 apply to any intervals and are not restricted to those commencing at zero; they shall also embrace any eccentricity of the dial in relation to the axis of rotation of th