1、 STD-BSI BS EN IS0 bLiZL-ENGL 1777 Lb24bb7 Ubb4311 O01 W BRITISH STANDARD Technical drawings - Simplified representation of centre holes The European Standard EN IS0 6411 : 1997 has the status of a British Standard CS 01.100.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW B
2、S EN IS0 6411 : 1997 BS 308 : Section 1.23 : 1997 BS EN IS0 6411 : 1997 I direction of the Engineering Amd. No. Sector Board, was published under the authority of the Standards Board and comes into effect on 15 December 1997 National foreword Date Textaffected This British Standard is the English ku
3、iguage version of EN IS0 6411 : 1997. it is identical with IS0 6411 : 1982. It partially supemedes BS 308 : Part 1 : 1993. It is envisaged that when the full range of European standards on technical drawing is implemented BS 308 will be withdrawn. The UK participation in its preparation was entruste
4、d to Technical Committee TDEY4, Engineering drawing, Metrology, Precision measurement and all related documentation, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible inte - monitor related international and European developments and promulgatc. th
5、em in the UK. A list of organizations represented on this committee can be obtained on request to its secretaqy. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally includr an annex which lists nonnative references to international publications with their correspo
6、nding European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the %in b) not a fundamental requirement; centre hole can b
7、e accepted on the finished part, but is c) centre hole shall not exist on the finished part. 11 At present at the stage of draft. 1 STD-BSI BS EN IS0 b4LL-ENGL L797 m 1b24bb9 Dbb43LB qbb m EN IS0 6411 : 1997 3.2 Simplified representation - the outside countersink centre hole diameter D. The symbols
8、representing centre holes and their application to the end face of a shaft are shown in column 2 of table 1. 3.3 Designation of centre holes The designation of centre holes is dependent on the drill and may be indicated with reference either to an International Stan- dard or to any other standard de
9、aling with this subject. The two values are separated by a solidus. Example : a centre holeil, type B with d = 2,5 nim and D3 = 8 mm may be indicated on the drawing as : IS0 6411-8 2,5/8 4 Interpretation of indication The designation of the centre hole itself consists of The relationship between the
10、 various designations used to - - - the pilot diameter d a reference to this International Standard; the letter for the type R, A or 6); specify the centre holes, the dimensions represented by the given designations, and dimensions depending on the centre drill used are shown in table 2. Further det
11、ails specifying the dimensions of the centre hole, to be indicated preferably on the drawings, are given in annex A. Table 1 - Representation and designation of centre holes on drawings Dimensions in rnillimetres Requirement Centre hole is required on the finished part Centre hole may remain on the
12、finished part Centre hole shall not exist on the finished part Representation Designation f-ySO 6411 - 6 2,5/8 IS0 6411 - 6 2,518 FI- fY+!SO 6411 - 6 2,5/8 1) For the machining of such a centre hole, a drill with d = 2.5 and dl = 10 according to IS0 2540 is used. 2 EN IS0 6411 : 1997 Table 2 - Inter
13、pretation of the designation Type of centre hole R with radius form (centre drill according to IC0 2541) A I without protecting chamfer (centre drill according to IS0 866) B with protecting chamfer (centre drill according to IS0 2540) Designation (examples) For dimension I, see annex A Interpretatio
14、n of the designation d = 3,15 DI= 6,7 Dimensions in millimetres I d =4 LI2= 0,5 * Dimension I depends on the length of the centre drill. It should not he less than r. 3 STD.BSI BS EN-IS0 b4LL-ENGL 1997 H Lb24bb- Obb4320 014 R according to IS0 2541 Dl EN IS0 6411 : 1997 .- A 0 according to IS0 866 ac
15、cording to IS0 2540 4 Annex A Dimensions for centre holes type R, A and B nom. 2,12 2.65 33 4.25 5,3 6,7 8,5 10.6 13.2 17,O 21.2 The dimensions which are necessary to specify a centre hole are shown in table 3. nom. 1 ,o6 1.32 1.70 2,12 2.65 3.35 4.25 5.30 6,70 8,50 10.60 13,20 17,OO 21,20 Table 3 -
16、 Dimensions of preferred centre holes Dimensions in millimetres d nom. (0.5) (0,631 10.81 1 .o ( 1,251 1,6 2.0 2.5 3,15 (5.0) 63 (8.01 10.0 4,o t ref. 03 0.6 0.7 0.9 1.4 1.1 13 2.2 2.8 3,5 4.4 5.5 8.7 7.0 03 nom. 3.15 4 5 6.3 8 10 12.5 16 18 =,4 28 1 ref. NOTE - Sizes in brackets should be avoided w
17、henever possible. 4 STD-BSI BS EN IS0 b4LL-ENGL. 1777 I-Lb24bb7 bb432L T50 D EN IS0 6411 : 1997 3.5 0,s Height of numerals and capital letters (h) Line thickness for symbols (d Annex B 5 7 10 14 20 0,5 0.7 1 1.4 2 Proportions and dimensions of symbols Line thickness for lettering (d) see 8.1.2 Heigh
18、t Hl 5 7 10 14 20 28 - In order to harmonize the sizes of the symbols specified in this International Standard with those of the other inscriptions on the drawing (dimensions, tolerances, etc.) the following rules shall be observed. B.2 Proportions The symbol and its complements shown in area a (see
19、 B.3) shall he drawn in accordance with the figure, B.l General requirements B.3 Dimensions 6.1.1 The symbols shown in the table shall be nSCrihed with a line thickness (d ) equal to 1 /10 of the height (h) of the letter- ing used for the dimensions in the relevant drawing. The range of sizes to be
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