Abstract: A chuck for rotatably supporting a bearing of a workpiece comprising a clamping fixture including a base member having a bearing surface selectively configured for matingly supporting a portion of the workpiece bearing, a jaw having a selectively configured bearing surface for matingly engaging with another portion of the workpiece bearing, means for displacing the work engaging jaw from a first position whereat the workpiece bearing will be forcefully clamped intermediate the base member and the jaw whereby rotation of the chuck will effect rotation of the workpiece, to a second position whereat the workpiece can be displaced relative to the base member and the jaw, at least one air pocket in the base member bearing surface, and means for directing pressurized fluid to the air pocket whereby when the jaw is at the second position the force required to displace the workpiece relative to the base member and the jaw will be reduced.