Model DPH-400W 4-inch diaphragm chuck with special jaws and stop to grip circulator pump bearing housing in-between the ears on the root diameter. Four of the six jaws are used because there are 8 ears. The pins are contoured to compensate for clamping diameter tolerance and diamond coated for extra grip. The O.D. and bore are machined and the part is ejected with an internal air piston.