For use with the Standard Pull Clamps. The pins are designed to be modified by the user to fit the actual workpiece thickness. For use with the Standard Pull Clamps. The pins are designed to be modified by the user to fit the actual workpiece thickness. Shank made from 4135 alloy steel, precision ground and the shank end is heat treated. The head made from 1045 alloy steel, heat treated with a black oxide finish.