Method for setting working origin and machine tool for implementing the same

A machine tool used for implementing a method for setting a working origin of a rotary tool relative to a work piece to be machined, said machine tool comprising:

• a main spindle for rotating said rotary tool;
• a sensor for detecting a rotation of said main spindle;
• a work table for holding said work piece to be machined;
• a driving source for applying, with a tip of a cutting edge of said rotary tool in contact with an outer surface of said work piece to be machined, a load torque to said main spindle to such an extent that said rotary tool is not rotated;
• and
• a controller having a working origin setting section that is adapted to set a coordinate as a working origin at a moment when the rotation of said main spindle is detected by said sensor during a jog feed, while, starting from the state in which said rotary tool is in contact with the outer surface of said work piece and said load torque is applied to said main spindle to such an extent that said rotary tool is not rotated, either said main spindle or said work table is moved in the jog feed in a direction such that said tip of said cutting edge is moved away from said outer surface.