This invention discloses a chuck apparatus actuated by a fluid including a body, a plurality of master jaws slidably mounted in the body, a fluid driven piston mounted for axial motion relative to the body along an axis, the piston comprising a plurality of bores extending therethrough along bore axes inclined with respect to the axis, and a plurality of shafts, each slidably mounted in one of the plurality of bores and being coupled to one of the master jaws, and wherein axial movement of the piston along the axis causes the plurality of shafts to move and to cause the plurality of master jaws to move therewith.