Northfield Precision Instrument’s Model 350 three-jaw air chuck mounts to a BT-30 VMC and is modified for spring clamp/air open. With TIR. of 0.0001", the 3" diameter chuck rotates as fast as 4,500 rpm. It is actuated via the coolant-through-spindle passage. The company says the chuck enables a standard VMC to be used as a vertical lathe with a pallet on one side for loading and unloading workpieces.