Patent ID: 7849769

Claim:
A precision workpiece turning lathe comprising: a bed; a head stock, mounted on the bed, including a main spindle for providing rotation for a cylindrical workpiece while holding one end of the cylindrical workpiece by a chuck, the head stock having an indexing axis (C axis) adapted to index the rotation of the cylindrical workpiece in a circumferential direction of the cylindrical workpiece; a tail stock located on the bed opposite to the head stock, the tail stock being adapted to rotatably support the other end of the cylindrical workpiece; a carriage including a saddle mounted on the bed movably in a longitudinal direction (Z, axis) of the cylindrical workpiece, and a table movably mounted on the saddle in a direction (X axis) substantially perpendicular to the longitudinal direction of the cylindrical workpiece; a tool swivel mounted on the table; a tool post mounted on the tool swivel, the tool post having a turning lathe cutting tool attached thereto; and a servomechanism configured to control a rotational position of the turning lathe cutting tool around a tool turning axis (A axis) along a longitudinal axis of the turning lathe cutting tool, wherein when machining a spiral groove on a circumferential surface of the cylindrical workpiece, the servomechanism orients and holds a cutting face of the turning lathe cutting tool in a position substantially perpendicular to a direction along which the spiral groove extends.