The invention relates to a chuck (1) for a machine tool for machining a tubular workpiece (26) which rotates about a rotational axis that coincides with the centre of the chuck, comprising at least two chucking slides (7a, b, c) that are designed to be positionable radially with respect to the rotational axis in order to release and chuck the workpiece, are arranged on the end side of and in a manner distributed uniformly around the circumference of a chuck head plate, and bear chucking jaws (8a, b, c). Such a chuck is intended to be created with improved operating characteristics and extension to all chucking functions. To this end, for the external central chucking of a tube (26), there are provided centring slides (27a, b, c) which can be disengaged from the chuck head plate with a forward inclination towards the end of the tube to be machined and centre the tube by means of chucking claws (29) which are arranged at the front, free end of centring slide rods (28), said centring slides (27a, b, c) engaging via a toothed rod section (34) into a toothing (35) of a drive means assigned to each centring slide, and meshing for their part, on a toothing side (37) parallel to the side with the toothing, with a central toothed wheel (33) arranged concentrically with the rotational axis, wherein the central toothed wheel (33) synchronizes the movements of all the centring slides (27a, b, c).