Find the most up-to-date version of BS at Engineering BRITISH STANDARD OBSOLESCENT AUGUST BS Incorporating Amendment Nos. 1, 2 and 3 Specification for Licensed. Standard. Line Drawing. Product Description. DIN HEXAGON FULL NUT. 70 . BS HEXAGON FULL NUT BSW. BS

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Unless otherwise stipulated by the purchaser, the choice of material shall be left to the manufacturer provided that the finished products satisfy the requirements for mechanical properties set out in Clauses 4 and 6 bs178 in Table 4 and Table 6 of Appendix A.

The former gauge length and its associated values have therefore been retained in this standard for the time being and a suitable amendment will be issued when the necessary bs178 can be supplied.

BS 统一精密六角螺栓、螺钉和螺母(UNC与UNF螺纹)规范_图文_百度文库

For highly stressed bolt applications, the definition and degree of such decarburization shall be negotiated between manufacturer and user. As a first stzndard, two standards for hexagon bolts, screws and nuts were published: For details of these and other benefits contact Membership Administration.

A circular recess in the upper surface of the head or, A line of contiguous circles indented on one or more of the flats of the hexagon and parallel to the axis of the bolt or screw. The test shall be made on the end ns1768 of the nuts. Measurement of the specimens subjected to the proof stresses for bolts or screws shall be performed in the following manner: With the exception of slotted nuts, all hexagon nuts chamfered at both ends shall also have a countersink as above at both ends of the thread.

For widths across flats, widths across corners, and diameter of washer face, see Table 2.

BS 1768:1963

The surfaces of these bolts and screws are customarily dull black from heat stanrard, although the manufacturer may machine some of the surfaces of the larger size bolts and screws after heat treatment. BSTable of approximate comparison of hardness scales. Clause 12 c ii. Various BSI electronic information services are also available which give details on all its products and services.

For bolts of strength Grade T and greater, the depth of decarburization, measured from the crest, shall not exceed 33 per cent of the height of the threads. This is in accordance with the American Standard from which these sizes are derived.


These nuts shall meet the requirements for proof load specified in Table 6. Complete freedom from any decarburization is achieved by shank grinding after heat treatment and before thread rolling; if this is required, it shall be the subject of negotiation between manufacturer and user.

This shall be checked by means of a screwed ring gauge with appropriate slot and a plain plug gauge which shall be a Go gauge in the minimum split-pin hole see Figure 21 in Appendix C. The Izod impact test on metals.

Screws shall wtandard threaded to permit of a screw ring gauge being screwed by hand to within a distance from the underside of the head not exceeding two and a half times the pitch for diameters up to and including 1 in and three and a half times the pitch for diameters over 1 in.

Birnell Hardness Licensed Copy: These nuts shall be capable of withstanding a proof load, based on the minimum tensile strength of Grade S Bolts, as laid down in Table 4, Column 2.

As equipment of sufficient capacity may not be readily available for nuts in this range, they shall meet the requirements for hardness specified in sub-clause c below.

When materials selected from this table are used, the mechanical properties referred to above are obtained by oil quenching and tempering at a suitable temperature.

Except as permitted under the Copyright, Designs and Patents Act no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means — electronic, photocopying, recording or otherwise — without prior written permission from BSI.

If steel bolts, screws or nuts are required bright all over, the purchaser should state this in his enquiry and order. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested.

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Nuts suitable for use with Bolts Grade T. The screw threads may be either cut or rolled at the option of the manufacturer and shall conform to the limits bs168 tolerances for Class 2A specified in BS BSSpecification for wrought steels for mechanical and allied engineering purposes — Part 1: Tolerances may be extrapolated from Table 1, Table 2 or Table 3 as appropriate.


When bolts and screws are made with rolled threads the lead formed at the end of the bolt by the thread rolling operation may be regarded as providing the necessary chamfer to the end, no other machining operation being necessary, and the end shall be reasonably square with the centre line of the shank.

The groove shall not standarrd 0.

The nominal length of a bolt or screw shall be the distance from the underside of the head to the extreme end of the shank including any chamfer or radius. Nuts of diameters over 1 in shall be subjected to a hardness test and their hardness sgandard not be less than that specified below: Cold forged bolts and screws.

The permissible tolerance standarr the nominal length shall be as given below: These tolerances should cover both the width of slot and the off-centre distance. An ordinary nut or its equivalent in the form of an adaptor shall be screwed on to the bolt or screw so as to be clear of the run-out of the thread towards the head and also stansard of any imperfect threads at the point, the load shall then be applied to the head and to the nut or adaptor.

BS 1768-1963 Unified hexagon head screws, washer faced

Details and advice can be obtained from the Copyright Manager. NOTE The preferred method of carrying out this test is to measure the length between conical centres on the centre line of the bolt or screw which has been set up on the mating centres of the anvils of the measuring fixture; the head or shank of the bolt or screw should be marked so that it can be placed in the same position for all measurements.

The test mandrel shall have a hardness of not less than HV Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service.