BS 4174:1972

Ferrous and non-ferrous. Gives general dimensions for countersunk, raised countersunk and pan head tapping screws with slotted or recessed heads, slotted mushroom heads, recessed flange heads and hexagon head tapping screws and round head metallic drive screws. Gauges for head flushness for corrosion head screws and for checking recess penetration of recessed head screws, together with testing requirements and a box with hole sizes also given.