Dimensions, tolerances and general requirements for sizes above and below ? in. Covers screws of the following types: 90 degrees countersunk and raised countersunk, round , pan, cheese and mushroom with slotted and with recessed heads. Appendices on dimensions of hexagon head screws and hexagon precision nuts in sizes below ? inch; flushness gauge for countersunk heads; penetration of standard gauge points for recessed heads; formulae for dimensions; tables of standard sizes.

? British Standards Institution 2013

General notes:
This standard has been declared obsolescent for a further period.

Amendment notes:
AMD 1561 published 15 September 1974
PD 5730 published 15 January 1966
PD 5905 published 11 August 1966

AS B50-1960 - Equivalent