BS 2827-1957 Specification for machine screw nuts pressed type (B A and Whitworth form threads)《机用压制螺母(Ｂ Ａ与惠氏螺纹)规范》.pdf

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1、BRITISH STANDARD BS 2827:1957 Incorporating Amendment No. 1 Specification for Machine screw nuts pressed type B.A. it should also be noted that the maximum minor diameters are slightly larger than those specified for the corresponding sizes of threads in BS93 3)and BS84 4) . Although no great accura

2、cy is called for either on the general dimensions or on the threads, it is considered that the nuts should always be adequate for the kind of work they are normally called upon to do. In preparing this standard, therefore, the aim has been to assist the production of pressed nuts of reasonable quali

3、ty, suitable for many general industrial purposes; they should not, of course, be used where they are subject to appreciable stress. The general dimensions specified for these nuts are based on current practice. Similarity between certain of the hexagon sizes given here and some of those specified f

4、or pressed nuts in BS1981 is purely coincidental. The need to ensure that these nuts can be produced economically would make it difficult to introduce any significant change; it is thought that the use within a single organization both of pressed nuts in accordance with this standard and of those sp

5、ecified in BS1981 is unlikely to be so extensive as to cause serious confusion. In accordance with BSI policy concerning the introduction of metric standards, this imperial standard has been declared obsolescent. It will be made obsolete in due course. A British Standard does not purport to include

6、all the necessary provisions of a contract. Users of British Standards are responsible for their correct 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 an

7、dii, pages1 to3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) BS 57, “B.A. screws, bolts, nuts and plain washers”. 2) BS1083, “Precision hexagon bolts, screws

8、, nuts and plain washers (B.S.W. and B.S.F. threads)”. 3) BS93, “B.A. screw threads”. 4) BS84, “Parallel screw threads of Whitworth form”.BS2827:1957 BSI 01-2000 1 1 Scope This British Standard relates to pressed nuts in ferrous or non-ferrous material, having B.A. or Whitworth form threads. General

9、 dimensions are given for square and hexagon nuts. The nuts specified in this standard are suitable for many general purposes but should not be used where they are subject to appreciable stress. 2 Material Steel nuts shall be manufactured from cold rolled strip, and brass nuts shall be manufactured

10、from cold rolled or extruded strip. The material shall have a tensile strength of not less than the following: If the purchaser requires the nuts to be manufactured from steel or brass of a higher tensile strength or of another material, he should specify the tensile strength and the material. 3 Dim

11、ensions The dimensions and tolerances for nuts shall be as specified inTable 1, Table 2, Table 3 andTable 4 andClause4. 4 Screw threads a) General. The screw threads shall be of one of the following series as specified by the purchaser: British Association (B.A.) in accordance with BS93, “B.A. screw

12、 threads”, British Standard Whitworth (B.S.W.), British Standard Fine (B.S.F.) or Whitworth series (Whit.) in accordance with BS84, “Parallel screw threads of Whitworth form”. NOTEBasically, the dimensions of these threads are in accordance with the standards quoted; the minimum major and effective

13、diameters are as given in BS93 and BS84 respectively, but the maximum minor diameters are slightly larger than those of standard screw threads. The axis of the screw thread shall be reasonably square with the face of the nut and reasonably central with the square or hexagon. b) B.A. screw threads. B

14、.A. screw threads shall conform to the limits and tolerances specified inTable 2 of this standard. See Note to sub-clausea) above. c) B.S.W., B.S.F. and other Whitworth screw threads. B.S.W., B.S.F. and other Whitworth screw threads shall conform to the limits and tolerances specified inTable 3 andT

15、able 4 of this standard. See Note to sub-clausea) above. Steel 25 tons/sq. in. Brass 20 tons/sq. in.BS2827:1957 2 BSI 01-2000 Table 1 Machine screw nuts, pressed type, square and hexagon GENERAL DIMENSIONS Figure 1 Square nut Figure 2 Hexagon nut 1 2 3 4 5 6 7 Nominal size of nut, D Width across fla

16、ts, A Width across corners Thickness, E Square, B Hexagon, C Whitworth B.A. Nominal Max. Min. Max. Min. Max. Min. in. in. in. in. in. in. in. 3 / 32 48 Whit. a 1 / 8 40 B.S.W. a 5 / 32 32 Whit. a 6 B.A. 5 B.A. a 4 B.A. & 3 B.A. a 0.250 0.250 0.312 0.244 0.244 0.306 0.353 0.353 0.442 0.289 0.289 0.36

17、1 0.082 0.082 0.095 0.078 0.078 0.091 3 / 16 24 B.S.W. 3 / 16 32 B.S.F. a 7 / 32 24 Whit. a 7 / 32 28 B.S.F. a 2 B.A. 1 B.A. a 0.375 0.437 0.369 0.429 0.530 0.619 0.433 0.505 0.106 0.128 0.102 0.123 1 / 4 20 B.S.W. 1 / 4 26 B.S.F. 5 / 16 18 B.S.W. 5 / 16 22 B.S.F. 0 B.A. 0.500 0.562 0.492 0.552 0.70

18、7 0.795 0.577 0.649 0.128 0.160 0.123 0.154 3 / 8 16 B.S.W. 3 / 8 20 B.S.F. 0.625 0.615 0.884 0.722 0.179 0.173 a These sizes are non-preferred and should be dispensed with wherever possible.BS2827:1957 BSI 01-2000 3 5 Gauging The quality of these nuts does not call for any very precise system of ga

19、uging. To ensure that they will assemble freely on external threads of basic size and that the nuts have an adequate depth of thread, it is recommended that they be checked merely by means of a GO screw plug gauge and a NOT GO plain plug for the minor diameter, made to the appropriate tolerances as

20、specified in BS919, “Screw gauge limits and tolerances”. It is not considered necessary to use a NOT GO effective diameter gauge on these nuts, and accordingly no maximum effective diameter is specified in the tables. Table 2 Limits for British Association (B.A.) screw threads Table 3 Limits for B.S

21、.W. and other Whitworth screw threads Table 4 Limits for B.S.F. screw threads See Clause4 a) and NOTE and Clause5 1 2 3 4 Nominal sizeof nut, D Major diameter Effective diameter Minor diameter Minimum (basic) Minimum (basic) Maximum in. in. in. 6 B.A. 5 B.A. a 4 B.A. 0.1102 0.1260 0.1417 0.0976 0.11

22、20 0.1262 0.095 0.109 0.123 3 B.A. a 2 B.A. 1 B.A. a 0 B.A. 0.1614 0.1850 0.2087 0.2362 0.1441 0.1659 0.1874 0.2126 0.140 0.162 0.182 0.207 a These sizes are non-preferred and should be dispensed with wherever possible. See Clause 4 a) and NOTE and Clause 5 1 2 3 4 Nominal sizeofnut,D Major diameter

23、 Effective diameter Minor diameter Minimum (basic) Minimum (basic) Maximum in. in. in. 3 / 32 48 Whit. a 1 / 8 40 B.S.W. a 5 / 32 32 Whit. a 0.0937 0.1250 0.1562 0.0804 0.1090 0.1362 0.077 0.104 0.129 3 / 16 24 B.S.W. 7 / 32 24 Whit. a 1 / 4 20 B.S.W. 0.1875 0.2187 0.2500 0.1608 0.1920 0.2180 0.152

24、0.183 0.208 5 / 16 18 B.S.W. 3 / 8 16 B.S.W. 0.3125 0.3750 0.2769 0.3350 0.265 0.321 a These sizes are non-preferred and should be dispensed with wherever possible. See Clause 4 a) and NOTE and Clause 5 1 2 3 4 Nominal sizeofnut,D Major diameter Effective diameter Minor diameter Minimum (basic) Mini

25、mum (basic) Maximum in. in. in. 3 / 16 32 B.S.F. a 7 / 32 28 B.S.F. a 1 / 4 26 B.S.F. 0.1875 0.2187 0.2500 0.1675 0.1959 0.2254 0.161 0.188 0.216 5 / 16 22 B.S.F. 3 / 8 20 B.S.F. 0.3125 0.3750 0.2834 0.3430 0.273 0.333 a These sizes are non-preferred and should be dispensed with wherever possible.BS

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