Machine tool and machining method

A machine tool for machining a joined workpiece, wherein the machine tool comprises a grip section for gripping the joined workpiece, wherein the joined workpiece comprises a first workpiece and a second workpiece joined at a joint portion between the first and second workpieces, wherein the machine tool comprises a support section for supporting the joined workpiece gripped by the grip section, wherein the joined workpiece is supported by the support section at an inner peripheral surface of the support section, which inner peripheral surface has a predetermined width, and wherein the joined workpiece is rotated by the grip section during the machining, wherein the machine tool further comprises:

• a control unit configured to control machining of the joint portion of the joined workpiece such that the first workpiece is gripped by the grip section with the joint portion of the joined workpiece projecting from the support section, and such that a predetermined joined workpiece region, extending from the joint portion of the joined workpiece toward the second workpiece, is machined over a range of not less than said predetermined width so as to have an outer diameter of not more than an outer diameter of the first workpiece so as to result in a machined joined workpiece;
• and
• wherein the control unit is also configured to control movement of the machined joined workpiece so as to slidingly move the machined joined workpiece relative to the support section, from a state in which the first workpiece is supported by the support section, up to a state in which the second workpiece is supported by the support section.