Bolt - 1/4in x 9/16in x 26tpi, zinc plated. CEI/ BSCY cycle thread. Flat head, Norton AJS matchless Triumph style pre 1970s. Matchless and AJS knee pad plate bolt. Use for mudguards etc where 1/2" bolt is too short and difficult to place. Original part number STD-70; 000070; 00-0070 knee pad plate screw