Work phase determination method for machine tools, and device therefor

In a machine tool in which a spindle housing supporting a specifically directed spindle for rotation is supported for motion by a numerical control mechanism, a work phase determination device comprising:

• a reference block fixed below and in vertical alignment with the spindle, the reference block having a first plane face perpendicular to a direction of the spindle and a second plane face parallel to both the direction of the spindle and the specific axis;
• a work support-feeding device comprising an intermediate table having a top face with opposite ends, a work driving table fixed on one end of the top face of the intermediate table, and a center push table fixed on the other end thereof, said work driving table having an NC table and a table main body fixed on the intermediate table;
• a chuck portion, supported on the table main body, rotatively driven around a specific axis in an X-axis direction by the NC table;
• and
• a drive center supported on the table main body and positioned on the specific axis, the drive center supporting a rotation center of an end of a work grasped by the chuck portion, the work having a phase reference section,
• wherein, in feed-rotating the work around the specific axis, a rotation angle of the work is corrected in accordance with a rotation angle of the NC table at a time of an abutment between the phase reference section of the work and the reference block.