Establishes dimensions for cup head bolts with square, oval and nibbed shanks, and countersunk headed bolts with square and nibbed shanks for use on steel work and wood work and with Whitworth threads. It includes square and hexagon nuts and a complete range of round and square washers with round and square holes. The range of nominal sizes covered is from 2 in. to 1 in. Requirements are laid down in respect of the lengths of threads and the tolerances on them, and the form of the end of the bolt shank.