British fastener standards became obsolete many years ago but are still in use in the fastener market and the fastener after market. British standards for fasteners should have been overtaken by ISO standards in fasteners and EN standards in fasteners but in practice the German DIN standards became the fastener market leaders. DIN 933, DIN 931 and DIN 912 being the most popular Metric fastener products in the world. When it comes to Inch washers the BS fastener standard is still in wide use.
Important dimensions of precision hexagon bolts, screws and nuts (B.S.W. and B.S.F. threads) as covered by British Standard 1083:1965. The use of fasteners in this standard will decrease as fasteners having Unified inch and ISO metric threads come into increasing use. Dimensions of Unified precision hexagon bolts, screws and nuts (UNC and UNF threads) are given in BS 1768:1963 (obsolescent); of Unified black hexagon bolts, screws and nuts (UNC and UNF threads) in BS 1769:1951 (obsolescent); and of Unified black square and hexagon bolts, screws and nuts (UNC and UNF threads) in BS 2708:1956 (withdrawn). Unified nominal and basic dimensions in these British Standards are the same as the comparable dimensions in the American Standards, but the tolerances applied to these basic dimensions may differ because of rounding-off practices and other factors.
General purpose screwed studs are covered in British Standard 2693: Part 1:1956. The aim in this standard is to provide for a stud having tolerances which would not render it expensive to manufacture and which could be used in association with standard tapped holes for most purposes. Provision has been made for the use of both Unified Fine threads, Unified Coarse threads, British Standard Fine threads, and British Standard Whitworth threads.