Abstract: A main spindle device has a main spindle (1) having a hollow hole, and a chuck unit (10) for grasping a work (W). A pipe unit (71) is inserted into the hollow hole of the main spindle (1) and receives insertion of the work (W) to thereby prevent the work (W) from vibrating when rotated together with the rotation of the main spindle. A support unit (72) supports the pipe unit (71) at one end of the main spindle (1) such that the axial line of the pipe unit (71) coincides with the axial line of the main spindle (1) and such that one end of the pipe unit (71) projects from the one end of the main spindle (1) to be positioned inside the chuck unit (10).

Abstract: The turning machine according to the present invention includes a displacement sensor (200) which measures a distance between an immobile reference point and a position of variable point which reflects the positional displacement of the tool, the immobile reference point being able to determine a relative positional correlation relating to a variable position of tools with the progress of machining of the workpiece (W) by the tool (421). In drawings the reference point is set up in the guide bush (90). And based on the measured result by the displacement sensor, the tool is moved so that the center height of the tool and the center line of the workpiece satisfy relatively the predetermined positional correlation. Accordingly, the center height deviation amount due to heat deformation and the like is corrected.

Abstract: A main spindle device has a main spindle (1) having a hollow hole, and a chuck unit (10) for grasping a work (W). A pipe unit (71) is inserted into the hollow hole of the main spindle (1) and receives insertion of the work (W) to thereby prevent the work (W) from vibrating when rotated together with the rotation of the main spindle. A support unit (72) supports the pipe unit (71) at one end of the main spindle (1) such that the axial line of the pipe unit (71) coincides with the axial line of the main spindle (1) and such that one end of the pipe unit (71) projects from the one end of the main spindle (1) to be positioned inside the chuck unit (10).

Abstract: The turning machine according to the present invention includes a displacement sensor (200) which measures a distance between an immobile reference point and a position of variable point which reflects the positional displacement of the tool, the immobile reference point being able to determine a relative positional correlation relating to a variable position of tools with the progress of machining of the workpiece (W) by the tool (421). In drawings the reference point is set up in the guide bush (90). And based on the measured result by the displacement sensor, the tool is moved so that the center height of the tool and the center line of the workpiece satisfy relatively the predetermined positional correlation. Accordingly, the center height deviation amount due to heat deformation and the like is corrected.