Abstract: A top jaw adapted for mounting on and attachment to the master jaw of a conventional work holding chuck and simultaneously during attachment thereof to be located radially against a fixed stop by a double T-nut of unique configuration, the latter being movable by an actuator screw in T-slots provided in the jaws, one portion of the T-nut and the complementary T-slot in the top jaw in which it is mounted being inclined with respect to and sloping toward the interface between the top and master jaws so that tightening of the T-nut by the actuator screw forces the top jaw radially against the stop and simultaneously axially against the mating surface of the master jaw, the taper angle of T-nut and the lead angle of the screw threads mutually cooperating to lock the top jaw on the master jaw in use.

Abstract: A work driver chuck having face and actuator plates interconnected by the pivot shafts of work holding cam jaws carried by and journaled for rotative movement in the face plate. Although normally centered on the rotational axis of the chuck, the assembly of plates and jaws is released for limited universal free floating movement during the actual work clamping operation to compensate for eccentricity of or surface irregularities in the workpiece. The actuator plate is slidable relative to the face plate and is operative as it moves to turn the jaws angularly into or out of engagement with the work.

Abstract: A chuck assembly of the type adapted to be mounted on a spindle of a machine tool including adjusting means for accurately aligning the central axis around which the work engaging jaws are disposed with the longitudinal axis of rotation of the machine tool spindle on which the chuck assembly is mounted. The work engaging jaws are of a composite construction, each including a main section and an insert section which is replaceable and which includes a first work engaging abutment for substantially rigidly engaging a piece of work and a second abutment axially spaced from the first abutment for yieldably engaging a piece of work and serving as a steady rest.