Simply by pressing on the locking lever, the eccentric crank is actuated to tilt the locking ring. This ring grips the center bar around its entire circumference with its chamfered part on the edges around the hole. The jaw is forcibly moved forward against the workpiece. A press advances the jaw by about 2 mm (5/64").

Returning the locking lever to vertical position permits the spring to put the locking ring back to neutral position, releasing the workpiece and allowing the center bar to be pulled back Clamping pressure can be adjusted by turning the ADJUSTING SCREW after first loosening the cover plate seen at the bottom of the housing portion.The center bar and locking mechanism are hardened and ground for smooth action and durability.