Abstract: The invention relates to a chuck in which the clamping jaws are connected with the chuck body via radially deflectable arms. Two flat parallel arms are preferably provided for each clamping jaw. These arms act like leaf springs and form a parallelogram link arrangement for the associated clamping jaw. The clamping jaws and arms are preferably designed in one piece with the chuck body by forming slots in corresponding projections of the chuck body by means of wire erosion. The clamping jaws are actuated in accordance with the invention via a wedge face arrangement comprising a two-armed lever for each clamping jaw. A short arm of the lever engages the associated clamping jaw whereas a wedge face provided on a distinctly longer arm of the lever interacts with an actuating element, in particular a roller, of the axially displaceable actuating member.

Abstract: A method for rough-turning and finishing a workpiece on a lathe wherein the lathe is provided with a tailstock center which is axially displaceable, a further center on the work spindle as well as axially displaceable front drivers and a chuck so that, for rough-machining, the workpiece is lifted off the work spindle center by means of the front drivers and driven by the chuck whereas, for finish-machining, the workpiece is held between the centers and driven by the front drivers.