Designed for heavier workpieces and machining loads. Used with a user-modified clamping pin or standard clamping screw. These clamps are similar to the Standard Pull Clamps, but they are designed for heavier workpieces and machining loads. They are designed to be used with a user-modified clamping pin or standard clamping screw. By rotating the handle, the clamp pulls the pin or screw downward and secures it in position. Four screws and a locating pin hole allows for secure fastening and precise locating of the clamp. Mounting bases are also available to provide top side mounting. The clamp consists of three holes for mounting a handle. Recommended workpiece thickness tolerance is +/-.5 mm for the 400 series and +/-.8 mm for the 500 series. The maximum handle load is 134 lbs. The body and clamp ring are made from 4140 alloy steel. The handle shaft is made from 1045 alloy steel. Parts are heat treated with a black oxide finish. Handle is black plastic.