Patent ID: 7850406

Claim:
A method for setting a working origin of a rotary tool relative to a work piece to be machined, comprising: applying to a main spindle which holds said rotary tool for rotation about an axis, with a tip of a cutting edge of said rotary tool in contact with an outer surface of said work piece, which is fixed to a work table, a load torque to such an extent that said rotary tool is not rotated; applying said load torque to said main spindle, and moving either said work table or said main spindle in a jog feed in a direction such that said tip of said cutting edge is moved away from said outer surface along an axial direction of said rotary tool or in a direction orthogonal to the axial direction; and setting a coordinate in a controller at a moment when said load torque causes said main spindle to start rotation as a working origin of said jog feed in the direction.