CHIP PARTING TOOL FOR TAPPING, AND FEMALE SCREW CUTTING METHOD

摘要

A female screw cutting method, comprising the steps of cutting chip parting grooves in the inner peripheral surface of a prepared hole (22) with a plurality of groove cutting blades (16) of a triangular shape in cross section by pressing the blade part (14) of a chip parting tool into the prepared hole (22) before tapping, whereby even if a work (20) is made of a highly expansible material, chips produced during the tapping can be surely separated by the chip parting grooves and excellently discharged, and accordingly it can be prevented that the chips are long and continuously entangled with a cutting tap or the cutting tap is broken due to the inclusion of the chips therein, and treatments such as chip cleaning can be easily performed.