Patent ID: 10259092

Abstract:
An apparatus for machining a cylindrical workpiece has a hollow spindle with a driving center on its tip end. The hollow spindle is rotationally journaled within a spindle unit. A tail stock spindle, with a centering center on its tip end, is rotationally supported and axially movable within a centering unit. A shaft-like kelly is non-rotationally and axially movably supported within an inner bore of the spindle. A drive rotates the spindle. Cylinders axially drive the kelly and the tail stock spindle, respectively. The spindle, the tail stock spindle and the cylinders are arranged on the same axial line. The cylindrical workpiece is sandwiched between the driving center and the centering center. An outer circumferential surface of the workpiece is finish machined while rotating the workpiece under a condition where the kelly engages the workpiece within an inner bore of the workpiece.