1 Scope
This British Standard specifies requirements and provides general dimensions and tolerances for the following types of cup head and countersunk head bolts and screws:
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• cup head bolts and screws;
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• cup head bolts with nibs;
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• cup head square neck bolts;
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• 90° countersunk head bolts and screws;
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• 90° countersunk head bolts with nibs;
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• 90° countersunk head square neck bolts;
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• 120° countersunk head square neck bolts.
Mechanical properties for steel bolts and screws are specified in BS EN ISO 898‑1.
This British Standard also specifies requirements for the nuts to be provided with bolts and screws conforming to this standard.
NOTE 1 A table summarizing the key requirements of BS 4933 is included in Annex A. This table does not list every requirement in BS 4933 but is just intended as a quick reference for users.
NOTE 2 It is considered that the range of nominal sizes included in this standard is adequate for most of the applications for which this series is likely to be employed, but for the convenience of users requiring larger sizes, further information is provided in Annex B.