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. The shank is made from 4135alloy steel, precision ground and the shank end is heat treated. The head is made from 1045 alloy steel, heat treated with a black oxide finish.