Abstract: The drill bit (14) passes through a drilling bush (2) for guiding said drill bit. The drilling bush (22) is pressed against the workpiece (10). However, the drilling bush does not terminate flush with the workpiece, but comprises a linear supporting edge (28) that overlaps the apex of the curvature of the workpiece. This prevents the drilling bush from sliding off a curvature of the workpiece surface.

Abstract: The machine tool comprises a workpiece carrier (16) into which crankshafts (10, 10a) can be clamped one above the other in horizontal alignment. The workpiece carrier (16) is fixed to a turntable (15) on a horizontal slide (14) with the turntable being pivoted around a vertical axis (A). After the turntable (15) has been brought into an inclined position, the crankshafts (10, 10a) are provided with oblique drill holes by means of the drills (26, 26a). A tool magazine (32) comprises a first circulating magazine (33) for drilling tools and a second circulating magazine (34) for drill bushings (27, 27a). The tools are exchanged between tool magazine (32) and spindle box (24) by means of the pick-up process.

Abstract: The machine tool comprises two headstocks (16,17), arranged on a support (10), which are movable independently of each other along their height and their longitudinal direction. A respective one (17) of the headstocks is active in the treatment of a workpiece attached on a workpiece carrier (20), while the other headstock (16) can be moved behind a tool magazine (24) for receiving a tool therefrom. While the one headstock is still working on the workpiece, the other headstock with the next tool can already be accelerated to the required working rotational speed and be advanced to the tool. Thus, the time required for exchange of tools is extremely shortened.

Abstract: The machine tool comprises two headstocks (16,17), arranged on a support (10), which are movable independently of each other along their height and their longitudinal direction. A respective one (17) of the headstocks is active in the treatment of a workpiece attached on a workpiece carrier (20), while the other headstock (16) can be moved behind a tool magazine (24) for receiving a tool therefrom. While the one headstock is still working on the workpiece, the other headstock with the next tool can already be accelerated to the required working rotational speed and be advanced to the tool. Thus, the time required for exchange of tools is extremely shortened.

Abstract: The machine tool comprises a machine stand (10) with a vertically movable vertical carrier (12) carrying a spindle head (SK1) for treatment of a workpiece. To exchange the spindle head (SK1) against a new spindle head (SK2), an exchange unit (15) is provided, comprising an exchange arm (16) pivotable by 90.degree. about a vertical axis (37). Two holding couplings (17,18) are mounted above each other on the exchange arm (16), each adapted to carry a spindle head (SK1,SK2). A delivery means (21), gripping the spindle heads from above, is used to supply the spindle heads for transfer to the exchange unit (15). The exchange unit (15) grips the spindle heads from the side. By pivoting the exchange arm (16) over 90.degree., the spindle head is pivoted to a position in front of the machine stand (10) and thus can be taken over by the vertical carrier (12).