Patent ID: 8887601

Claim:
A machine tool, comprising: front and back spindles, said front and back spindles facing each other and being rotatable on a common axis, and each of said front and back spindles being capable of gripping a workpiece, and rotating said workpiece on said common axis; a guide bushing having an axis aligned with said common axis of the spindles; and at least one tool post for supporting a tool used for machining a workpiece, said at least one tool post being positionable so that tools supported thereby can machine a part of a workpiece extending from said guide bushing toward the front spindle and alternatively machine a part of the workpiece extending from said guide bushing toward the back spindle; wherein the guide bushing is disposed between the front and back spindles and has a first end facing the front spindle and an opposite end facing the back spindle; and wherein the guide bushing is configured so that the workpiece gripped either by the front spindle or the back spindle can be inserted through the guide bushing, the guide bushing is movable along the direction of said common axis and capable of guiding a part of said workpiece extending from said guide bushing toward said front spindle by said first end of said guide bushing when said workpiece is gripped and rotated by the rear spindle, and said guide bushing is capable of guiding a part of said workpiece extending from said guide bushing toward said rear spindle by said opposite end of said guide bushing when the workpiece is gripped and rotated by the front spindle; whereby, when a tool supported by one of said at least one tool posts machines the workpiece while the guide bushing is used to guide the workpiece, the guide bushing can be located between the spindle gripping the workpiece and the tool machining the workpiece, and can guide the part of the workpiece extending from said guide bushing on the side of said guide bushing facing the spindle other than the spindle gripping the workpiece.