Abstract: A chuck for gripping a workpiece during a rotary operation includes a chuck body with a master jaw movably mounted on the chuck body. The master jaw includes a bayonet type locking structure. The master jaw also includes a face with at least one pin reciprocally mounted in and extending perpendicularly from the face. The pin is mechanically coupled to a piston reciprocally mounted in a piston chamber in the master jaw. The piston chamber is in communication with a source of pressurized fluid. The pin is reciprocated by selected communication of pressurized fluid to the piston chamber. A quick-change top jaw is also provided that may be quickly attached to and removed from the master jaw. The top jaw includes a bayonet type locking structure complementary to the bayonet type locking structure on the master jaw. The top jaw also includes an insert for capturing the pin in the master jaw.