SETTING DEVICE OF COORDINATE SYSTEM IN MACHINE TOOL

PURPOSE:To easily set a coordinate system and obtain good accuracy of machining, by bringing a work into contact with the surface of a work to calculate correction data after the work is tentatively cut by the optional tool. CONSTITUTION:After tentative cutting, a device, leaving the edge point of an optional tool as brought into contact with the peripheral surface or the end surface or a work W, reads position data XDP, ZDP of the edge point from a machining original point A while measures an actual value XIN, ZIN of a diameter and the end surface of the work W by a micrometer or the like. Here Xw'm Zw' are assumed for a coordinate value from a machine original point O being a coordinate system preset value to the machining original point A, and a difference value between the position data of this coordinate system and the actually measured value is a correction value XER, ZER from the machin ing original point A. Accordingly, a coordinate value Xw, Zw from the machine original point O being a true coordinate system to the original point A is obtained by adding the correction value XER, ZER to the preset value Xw', Zw'.