Island Park, NY… Northfield Precision Instrument Corporation, a leader in the design and manufacture of precision workholding chucks, introduces their Model DPH-400W 4 inch diameter diaphragm chucks with special jaws and stops. The stops have 3 small “Air Detect” holes for part seating conformation. Air is pumped through these holes, and when the part rests on the stop, the air pressure rises, tripping a pressure switch telling the machine to start machining. The 4 clover adapters have grooves for a CAM follower to snap into to orient the chuck when stopped. Up top is an eight passage rotary union to actuate all four chucks independently. These are mounted to a 4 spindle Theilenhaus machine.