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1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI British Standards Specification for precision vernier height gauges BS 1643:2008 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS
2、1643:2008BritiSh Standard Publishing and copyright information the BSi copyright notice displayed in this document indicates when the document was last issued. BSi 2008 iSBn 978 0 580 62081 2 iCS 17.040.30 the following BSi references relate to the work on this standard: Committee reference tdW/4 dr
3、aft for comment 08/30178093 dC Publication history First published april 1983 Second (present) edition, november 2008 Amendments issued since publication Amd. No. Date Text affected Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI Briti
4、Sh Standard BSI 2008 i BS 1643:2008 Summary of pages this 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. Contents Foreword ii introduction 1 1 Scope 1 2 normative references 1 3 terms and definitions 1 4 Construction 3 5
5、Scales 5 6 accuracy of reading 8 7 Protection 8 Annexes annex a (normative) Methods of test 9 Bibliography 11 List of figures Figure 1 Example and nomenclature of a precision vernier height gauge 2 Figure 2 Enlarged view of vernier scales 6 Figure 3 distance of vernier from main scale 7 List of tabl
6、es table 1 Measuring ranges 3 table 2 Layout of scales Metric scales 5 table 3 Layout of scales imperial scales 5 table 4 deviation of reading Metric 8 table 5 deviation of reading imperial 8 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c)
7、 BSI BS 1643:2008 ii BSI 2008 BritiSh Standard Foreword Publishing information this British Standard is published by BSi and came into effect on 20 november 2008. it was prepared by technical Committee tdW/4, Technical product realization. a list of organizations represented on this committee can be
8、 obtained on request to its secretary. Supersession this British Standard supersedes BS 1643:1983, which is withdrawn. Relationship with other documents prEn iSO 13225-1 is in preparation and covers design and metrological characteristics of simple vertical length measuring instruments for linear-di
9、mensional measurements perpendicular to a surface plate with either analogue or digital indication. Information about this document this new edition has been fully revised to bring it up to date. Presentational conventions the provisions of this standard are presented in roman (i.e. upright) type. i
10、ts requirements are expressed in sentences in which the principal auxiliary verb is “shall”. Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element. Contractual and legal considerations this publication does not purpo
11、rt 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. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c)
12、BSI BritiSh Standard BSI 2008 1 BS 1643:2008 Introduction the principal features of a vernier height gauge are shown in Figure 1 but details of design may vary between manufacturers. the accuracy of performance of a vernier height gauge is based upon the quality and precision of the various features
13、, e.g. the accuracy of the dividing of the scales, the quality of the graduation marks, the straightness of the guiding edge, the flatness of the base datum and the measuring faces. these are all features which the manufacturer controls in order that measurements made with the instrument are reliabl
14、e within the tolerances given in Clause 6. 1 Scope this British Standard specifies requirements for the construction, accuracy at the reference temperature of 20 C and the protection of metric and imperial precision vernier height gauges which include a scriber for marking heights. the metric height
15、 gauges measure height up to a maximum of 1 000 mm using a main scale and vernier scale graduated to read to 0.02 mm. the imperial height gauges measure height up to a maximum of 48 in using a main scale and vernier scale graduated to read to 0.001 in. NOTE 1 Attention is drawn to the fact that the
16、metric dimensions are not necessarily direct conversions of the imperial dimensions. For instance, the vernier division of 0.02 mm marked on the metric height gauge corresponds to a 0.001 in vernier division on the imperial height gauge, whereas the actual conversion is 0.001 in = 0.0254 mm. require
17、ments for setting blocks which might be supplied are also specified. Methods of testing height gauges are specified in annex a. 2 Normative references the following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For
18、undated references, the latest edition of the referenced document (including any amendments) applies. BS 817, Specification for surface plates 3 Terms and definitions For the purposes of this British Standard the following terms and definitions apply. NOTE The components of a precision vernier heigh
19、t gauge are illustrated in Figure 1, which also gives the nomenclature. 3.1 measuring range range of heights that the gauge can be used to measure without the vernier scale extending beyond the main scale 3.2 zero datum surface plane that supports both height gauge and the object to be assessed for
20、height Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 1643:2008 2 BSI 2008 BritiSh Standard 3.3 deviation of reading difference between the actual height of a designated measuring face above the zero datum surface and the vernier r
21、eading Figure 1 Example and nomenclature of a precision vernier height gauge 1 2 5 6 7 20 15mm 10 0 mm 3 4 8 9 10 11 12 13 14 15 16 17 18 10mm Key Fine adjustment1 Fine adjustment clamp2 Slider3 Locking mechanism (e.g. locking screw)4 Vernier scale5 Beam6 Main scale7 Base8 Base datum9 relief10 Zero
22、datum plane11 Guiding edge12 Measuring face see 13 4.8 b) Measuring face see 14 4.8 c) Scriber15 Measuring jaw16 Measuring face see 17 4.8 a) Scriber clamp18 NOTE The illustrations are not intended to specify details of design. Licensed Copy: London South Bank University, South Bank University, 31/0
23、1/2009 03:43, Uncontrolled Copy, (c) BSI BritiSh Standard BSI 2008 3 BS 1643:2008 4 Construction 4.1 Material the principal components shall be of carbon steel or stainless steel. the coefficient of thermal expansion within the temperature range of 10 C to 30 C shall be within (11.5 + 1.0) 106/C. th
24、e measuring faces of the sliding jaw and the underside of the base shall be hardened to not less than 700 hV for carbon steel and not less than 500 hV for stainless steel. the scriber shall be hardened throughout to not less than 700 hV. Finished height gauges shall be free from internal stresses. 4
25、.2 Measuring ranges the measuring ranges shall be as shown in table 1. table 1 Measuring ranges Metric mm Imperial in 0 to 3000 to 12 0 to 4500 to 18 0 to 6000 to 26 0 to 1 0000 to 36 0 to 48 4.3 Beam When tested in accordance with A.5, any recorded deflection shall be not greater than 0.05 mm, and
26、the cross section of the beam shall be such as to ensure rigidity during measurement and marking out. the beam shall be long enough to prevent overhang of the slide assembly at the nominal measuring range. 4.4 Base the base shall be of sufficient size to ensure the stability of the gauge. it shall b
27、e relieved on the underside, leaving a surface around the outside edge at least 5 mm or 0.25 in wide and shall have an air groove machined across this surface. the base datum shall have a surface texture less than 0.1 m Ra or 4 in Ra at a sampling length of 0.8 mm. When tested in accordance with A.4
28、, any departure from flatness shall be of a concave nature and shall not exceed 0.005 mm or 0.000 2 in as measured over the length or width of the base. Sharp edges shall be removed. 4.5 Slider the slider shall be a good sliding fit over the full working height of the gauge and shall not move under
29、its own weight. a fitting shall be incorporated to give fine adjustment of the slider. a locking mechanism shall be provided on the slider so that it can be effectively locked after fine adjustment has been made and in such a manner Licensed Copy: London South Bank University, South Bank University,
30、 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 1643:2008 4 BSI 2008 BritiSh Standard that the setting of the vernier scale relative to the main scale is not altered. Parallelism of the measuring faces with a zero datum surface shall remain within its tolerance upon clamping or locking the slider.
31、4.6 Measuring jaw the projection of the measuring jaw from the guiding edge of the beam shall be not less than the projection of the base from the guiding edge of the beam. For all positions of the slider on the beam, the gauging surfaces of the measuring jaw shall be flat and parallel to a zero dat
32、um surface within 0.008 mm or 0.000 3 in when tested in accordance with A.3 and A.6 and shall have a surface texture less than 0.1 m Ra or 4 in Ra at a sampling length of 0.8 mm. When the design of the instrument requires the depth of the measuring jaw to be taken into account when setting or readin
33、g, the measuring jaw shall be marked clearly with its depth, and its measured depth shall be within 0.01 mm or 0.000 4 in of the marked size. 4.7 Scriber the measuring faces of the scriber shall be flat and parallel to within 0.005 mm or 0.000 2 in when tested in accordance with A.3 and A.6 and shal
34、l have a surface texture less than 0.1 m Ra or 4 in Ra at a sampling length of 0.8 mm. the projection of the scriber beyond the end of the measuring jaw shall be at least 25 mm or 1 in. When the design of the instrument requires the depth of the scriber to be taken into account when setting or readi
35、ng, the scriber shall be marked clearly with its depth, and its measured depth shall be within 0.01 mm or 0.000 4 in of the marked size. a clamping device shall be provided to locate and retain the scriber in position on the measuring jaw. 4.8 Measuring face a height gauge shall have one or more of
36、the following designated as measuring faces (see Figure 1). the top face of the measuring jaw.a) the lower face of the measuring jaw.b) the underside of a scriber allowing the instrument to read zero c) when the underside of the scriber is coplanar with the base datum. 4.9 Setting block if the heigh
37、t gauge will not permit direct reading from zero with the manufacturers scriber clamped to the measuring jaw, a setting block shall be provided for checking the scale and vernier reading at one position. it shall have hardened faces, flat and parallel to within 0.005 mm or 0.000 2 in, and its mean m
38、easured length shall agree with its marked size to within 0.005 mm or 0.000 2 in. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BritiSh Standard BSI 2008 5 BS 1643:2008 5 Scales 5.1 General the layout of the main scale and vernier sc
39、ale shall be as shown in table 2 or table 3. the minimum length of the main scale shall be the nominal measuring range of the instrument plus the length of the vernier scale. Provision shall be made for re-setting the zero position. NOTE It is recommended that for ease of reading, the surface of the
40、 beam and vernier should have a dull finish, and the graduated lines should be black. table 2 Layout of scales Metric scales Main scaleVernier scale GraduationsGraduations and numbering Number of divisions LengthGraduations and numbering Other marking 1 mm intervals see Figure 2 a) Each 5 mm line ex
41、tended. Zero and each 10 mm line extended and numbered: 0 10 mm 20 30 40 50 etc. 5049 mmZero and each 5th line extended and numbered: 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 VEr 0.02 mm 1 mm intervals see Figure 2 b) Each 5 mm line extended. Zero and each 1 cm line extended and numbered: 0 1 cm 2
42、3 4 5 6 etc. 5049 mmZero and each 5th line extended and numbered: 0 1 2 3 4 5 6 7 8 9 0 VEr 0.02 mm table 3 Layout of scales Imperial scales Main scaleVernier scale GraduationsGraduations and numbering Number of divisions LengthGraduations and numbering Other marking 0.050 in intervals see Figure 2
43、c) Zero and each inch line extended and numbered: 0 1 in 2 3 4 5 6 etc. Each 0.1 in line extended 502.450 inEach 5th line extended. Zero and each 10th line extended and numbered: 0 10 20 30 40 50 VEr 0.001 in Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncon
44、trolled Copy, (c) BSI BS 1643:2008 6 BSI 2008 BritiSh Standard Figure 2 Enlarged view of vernier scales 0 230 240 250 260 270 280 290 300 310 Ver 0.02 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 21 0 3 4 5 6 7 8 9 10 11 Ver 0.02 1 2 3 4 5 6 7 8 9 0 21 0 6 7 8 9 10 20 30 40 50 2 1 Ver .001 in. a) with ma
45、in scale engraved in millimetres b) with main scale engraved in centimetres c) with main scale engraved in inches Key Main scale1 Vernier scale2 5.2 Graduation marks the main scale and vernier scale graduation marks shall be clear and square to the edge of the beam and the width of the marks shall b
46、e not less than 0.08 mm or 0.003 in and not more than 0.18 mm or 0.007 in. the variation of line thickness shall not exceed 0.05 mm or 0.002 in throughout an instrument when checked in accordance with A.7. 5.3 Fitting of vernier scale with main scale the distance from the graduated face of the beam
47、to the edge of the graduated face of the vernier shall not exceed 0.1 mm or 0.004 in (see Figure 3). Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BritiSh Standard BSI 2008 7 BS 1643:2008 Figure 3 Distance of vernier from main scale
48、0.1 mm max. 0.1 mm max. 2 3 1 0.1 mm max. 1 3 2 3 1 2 Overlaid vernier a) Metric Overlaid vernierEdge to edge vernier 0.004 in max. 0.004 in max. 2 33 1 2 1 0.004 in max. 1 3 2 Overlaid vernier b) imperial Overlaid vernierEdge to edge vernier Key Beam1 Vernier2 Slider3 5.4 Marking (other than gradua
49、tion marks) the beam shall be marked with the unit symbol of the scale figures, i.e. either a) mm or cm, or b) in. the vernier scale shall be marked with the value of a vernier division, i.e. VEr 0.02 mm or VEr 0.001 in. Each height gauge shall have clearly and permanently marked upon it, in characters not less than 1 mm high, the manufacturers name or trade mark. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:43, Uncontrolled Copy, (c) BSI BS 1643:2008 8
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