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 1Bevel protractors (mechanical and optical) Requirements and test methodsBS 1685:2008Incorporating Corrigendum No.
2、 1 BS 1685:2008 BRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the document was last issued. BSI 2009ISBN 978 0 580 68740 2ICS 17.040.30The following BSI references relate to the work on this standard: Committee reference TDW/4
3、Draft for comment 08/30177880 DCPublication historyFirst published May 1951 Second edition November 2008Amendments issued since publicationAmd. No. Date Text affected C1 August 2009 See forewordBRITISH STANDARD BSI 2009 iBS 1685:2008Summary of pagesThis document comprises a front cover, an inside fr
4、ont cover, pages i to ii, pages 1 to 6, an inside back cover and a back cover.ContentsForeword ii1 Scope 12 Nomenclature 13 Normative references 14 Material 15 General design and workmanship 26 Body 27 Stock 38 Blade 49 Acute angle attachment 410 Graduations 411 Marking 612 Case 6List of figuresFigu
5、re 1 Nomenclature for mechanical bevel protractors 2Figure 2 Nomenclature for optical bevel protractors 3Figure 3 Blade 3Figure 4 Zero position 5Figure 5 Length of graduations 5Figure 6 Section through scale and vernier 5BS 1685:2008ii BSI 2009BRITISH STANDARDForewordPublishing informationThis Briti
6、sh Standard is published by BSI and came into effect on 30 November 2008. It was prepared by Technical Committee TDW/4, Technical, product realization (TPR). A list of organizations represented on this committee can be obtained on request to its secretary.SupersessionThis British Standard supersedes
7、 BS 1685:1951, which is withdrawn.Information about this documentThis new edition has been fully revised to bring it up to date.The start and finish of text introduced or altered by Corrigendum No. 1 is indicated in the text by tags PQ.Presentational conventionsThe provisions of this standard are pr
8、esented in roman (i.e. upright) type. Its 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 considera
9、tionsThis publication does not purport 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.BRITISH STANDARD BSI 2009 1BS 1685:20081 ScopeThis standard relates to the
10、following types of bevel protractors:a) Mechanical.Type A. With vernier graduated to read to five minutes of arc, and with slow motion device, and acute angle attachment.Type B. With vernier graduated to read to five minutes of arc, but without slow motion device or acute angle attachment.Type C. Wi
11、th scale graduated in degrees, without vernier or slow motion device or acute angle attachment.b) Optical. With an internal circular scale which is graduated in divisions of 10 minutes of arc1)and read against a fixed index line or vernier by means of an optical magnifying system integral with the i
12、nstrument, enabling readings to be taken, by estimation or otherwise, to approximately two minutes of arc.2 NomenclatureFor the purpose of this standard the nomenclature indicated in Figure 1 and Figure 2 has been adopted for mechanical and optical types of bevel protractors respectively.NOTE With t
13、he exception of the requirements for graduations, which are set out in detail in Clause 10, the following clauses apply both to mechanical and optical types of bevel protractors.3 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated
14、 references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.BS 869, Specification for Toolmakers flats and high precision surface platesBS EN 12540, Corrosion protection of metals Electrodeposited coatings of n
15、ickel, nickel plus chromium, copper plus nickel and copper plus nickel plus chromiumBS EN ISO 18265, Metallic materials Conversion of hardness values4 MaterialAll parts of the protractor which constitute working parts shall be made of good quality steel which may, if desired, be of the stainless typ
16、e. The working edges of the blade or blades and the acute angle attachment shall have a diamond pyramid hardness number of not less than 450 (45 Rockwell C scale) or equivalent according to BS EN ISO 18265.1)Present known instruments are graduated to 10 minutes of arc but other suitable values of gr
17、aduation arc permissible. NOTE Attention is drawn to the fact that the metric dimensions are not necessarily direct conversions of the imperial dimensions.COMMENTARY ON 1: The fitting of an acute angle attachment is optional.BS 1685:20082 BSI 2009BRITISH STANDARDThe blade section of the protractor s
18、hall be manufactured in one continuous length from carbon steel, carbon steel matt chrome plated in accordance with BS EN 12540 or rust-resisting steel. The steel shall be hardened and tempered and shall have a hardness of 450 to 550 HV or equivalent according to BS EN ISO 18265.5 General design and
19、 workmanshipThe general workmanship and finish shall be good throughout. The rotational movement shall be smooth and Type A protractors shall incorporate a thumb pinion or other suitable device to assist in fine setting. The design shall incorporate an effective clamp and no change in reading shall
20、be observed on clamping.6 BodyThe protractor shall be so designed that the back of the body is flat and that there are no projections beyond the plane of the back. When the protractor is placed on its back on a surface plate or toolmakers flat conforming to BS 869, there shall be no rocking perceiva
21、ble to the naked eye. When the protractor is placed with the working edge of the stock on a surface plate or toolmakers flat conforming to BS 869 and the blade set at 90, the side of the blade and the back of the protractor body shall be square laterally with the surface plate or toolmakers flat to
22、within 0.075 mm per 25 mm/0.003 in. per inch.Figure 1 Nomenclature for mechanical bevel protractors145689101211723NOTE The illustrations are diagrammatic only, and are not intended to illustrate details of design.Key1 Blade lock nut2 Turret3 Main lock nut4 Blade5 Working edge6 Acute angle attachment
23、 7 Lock nut8 Stock 9 Working edge10 Body11 Scale12 VernierPQBRITISH STANDARD BSI 2009 3BS 1685:2008Figure 2 Nomenclature for optical bevel protractors1891023117465NOTE The illustrations are diagrammatic only, and are not intended to illustrate details of design.Key1 Blade2 Body3 Turret4 Working edge
24、5 Acute angle attachment6 Lock nut7 Stock8 Blade clamp9 Eyepiece10 Main clamp11 Working edgeFigure 3 Blade160 45Key1 PLength of bladeQ7 StockThe working edge of the stock shall be not less than 90 mm/3 in long and shall have a thickness of not less than 4.8 mm/316 inch in the case of mechanical type
25、s, and not less than 6 mm/ in in the case of optical types. It shall be straight to 0.010 mm/0.000 4 in.Any departure from true straightness shall be in the nature of a concavity, the extent of which shall not exceed 0.01 mm/0.000 4 in. when measured over the total span of the surface concerned.PQNO
26、TE The thickness of 4.8 mm/316 in for mechanical types has been adopted to accommodate the present practice of manufacturers but it is desirable that the minimum thickness should be 6 mm/ in.BS 1685:20084 BSI 2009BRITISH STANDARD8 BladeThe blade shall be either 150 mm/6 in or 300 mm/12 in long. The
27、ends of the blade shall be bevelled in the manner illustrated in Figure 3 to 60 and 45 respectively, and shall be accurate to within 5 minutes of arc.The blade shall be not less than 14 mm/1732 in wide and not less than 1.25 mm/0.05 in thick.The blade shall be so designed that it can be moved along
28、the turret throughout its whole length, and also be reversed. An effective method of clamping shall be provided.The sides of the blade or blades shall be flat to within 0.125 mm/0.005 in and 0.25 mm/0.010 in for the 150 mm/6 in and 300 mm/12 in blades respectively.The working edges of the 150 mm/6 i
29、n blades shall be straight to 0.010 mm/0.000 4 in and parallel to P0.012 5 mm/0.000 5 inQover their lengths.The working edges of the 12 in/300 mm blades shall be straight to 0.020 mm/0.000 8 in and parallel to 0.025 0 mm/0.001 in over their lengths.9 Acute angle attachmentThe working edge of the acu
30、te angle attachment shall be not less than 75 mm/3 in long and the thickness shall correspond to that of the blade. The working edge shall be straight to within P0.005 mm/0.000 2 inQ and, according to the type of attachment, shall be parallel with, or square to, the working edge of the stock to with
31、in 0.012 5 mm/0.000 5 in over the length of the attachment in all its positions.10 Graduationsa) Mechanical types. The diameter of the graduated circle shall be not less than 50 mm/2 in at the reading edge. The protractor may be so designed that the scale is either on the body or on the turret.The s
32、cale shall be graduated either as a full circle marked 0-90-0-90 (four quadrants) with one vernier, or alternatively as a semicircle marked 0-90-0 with two verniers 180 apart. All verniers shall read in both directions. One zero position shall be when the blade is parallel to the stock (see Figure 4
33、). The acute angle reading shall then be zero, or 90, according to the type of acute angle attachment with which the protractor is fitted.All graduations shall be clearly engraved. The thickness of the graduations shall be neither less than 0.064 mm/0.002 5 in nor more than 0.09 mm/0.003 5 in. The t
34、hickness of the graduations of the vernier and main scale shall be equal, as observed by the eye. The visible length of the shortest graduations on both the scale and vernier (dimensions L, Figure 5) shall be approximately equal to twice the width of the interval between adjacent lines. The distance
35、 from the face of the scale to the face of the vernier or zero index (dimension T, Figure 6) shall not exceed 0.10 mm/0.004 in. BRITISH STANDARD BSI 2009 5BS 1685:2008Figure 4 Zero positionFigure 5 Length of graduations10153045600 1530456001020203040L2L1Figure 6 Section through scale and vernierTPro
36、tractors without verniers shall be graduated in degrees, and the error of indication in any position of the blade shall not exceed plus and minus one-fifth of a degree.Protractors with verniers shall be graduated to read direct to five minutes of arc, and the error of indication in any position of t
37、he blade, including the use of the acute angle attachment if fitted, shall not exceed plus and minus five minutes of arc.BS 1685:20086 BSI 2009BRITISH STANDARDNOTE It is recommended that, for ease of reading, the scale and vernier should have a dull chromium finish. b) Optical type. The scale shall
38、be graduated as a full circle marked 0-90-0-90 (four quadrants). The zero positions shall be when the blade is parallel to the stock. The acute angle reading shall then be zero or 90, according to the type of acute angle attachment, when fitted.All graduations shall be clearly defined. The thickness
39、 of the graduations shall be equivalent to not less than one minute and not more than two minutes of the circle. The thickness of the graduations of the scale and the index line or vernier shall be equal, as observed through the optical system.The scale and index line or vernier shall be in focus in
40、 the optical system simultaneously.It shall be possible to adjust the focus of the optical system to accommodate normal variations in eyesight (including vision corrected by spectacles, or contact lenses) and the field of view shall appear clearly illuminated when the instrument is held to a light.T
41、he error of indication of the protractor in any position of the blade, including the use of the acute angle attachment if fitted, shall not exceed two minutes of arc.11 Marking Each protractor shall have legibly and permanently engraved upon it the manufacturers name or trade mark and an identificat
42、ion number.12 CaseEach protractor shall be supplied in a suitable protective case or box.This page deliberately left blankBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporate
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