Exchangeable turning head, particularly a face turning head

A turning head, particularly a face turning head for a spindle of a machine tool, comprising a housing, a rotating part having an axis and rotatably mounted to said housing, said rotating part including a setting rod receiving bore and being axially fixed to said housing, a setting rod movable in said bore in axial directions, a tool slide movably mounted to one axial end of said rotating part, said rotating part having a slideway extending transversely to the axis of said rotating part, said tool slide being movable in said slideway and having a keyway extending at an angle to the axis of said rotating part, said setting rod having a jib key part extending into said keyway and moving said slide upon axial motion of said setting rod, a conical intermediate piece fixed to and extending from an opposite axial end of said rotating part, said intermediate piece being axially aligned with the axis of said rotating part, a drive shaft extending substantially parallel to and being radially spaced from the axis of said rotating part, said drive shaft being mounted for rotation to said housing, an inner bearing shell fixed to said setting rod for axial and rotational motion therewith, said inner bearing shell being rotatably fixed to said rotating part for co-rotation with said rotating part and being axially movable with respect to said rotating part, an outer bearing shell rotatably mounted and axially fixed to said inner bearing shell, said outer bearing shell being rotatable with respect to said setting rod, means engaged between said outer bearing shell and said housing for rotationally fixing said outer bearing shell to said housing while permitting axial motion of said outer bearing shell with respect to said housing, transmission means connected between said drive shaft and said outer bearing shell for moving said outer bearing shell axially and independently of said rotating part and for transmitting rotation of said driving shaft into axial motion of said outer bearing shell and thus of said setting rod, a block mass movably connected to said rotating part near said one axial end thereof, and means connected to said block mass and said tool slide to shift said block mass in respect of opposite directions to said slide for counterbalancing centrifugal forces during rotation of said rotating part.