Dimensions of: hexagon and square bolts, screws and nuts with B.S.W. threads; bolts and screws faced under the head (with or without turning on the shank), hexagon and square nuts faced on one or both sides and hexagon lock-nuts, with B.S.W. or B.S.F. threads. Material, chamfering and facing, squareness of thread to face of nuts, drilled holes, split-pin sizes, stock lengths of hexagon head black bolts in sizes up to 1 in.Cross References:BS 28BS 84BS 916:413F-418F, 421F-426F, 429F-441FBS 1580BS 1769BS 3643Incorporates the following:PD 1894 published 15 May 1954PD 4164 published 15 May 1961PD 4331 published 15 October 1961PD 5906 published 11 August 1966