TAP FOR SCREW CUTTING AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a tap for screw cutting which realizes "burrless screw machining" without generation of burrs by slightly remodeling a new tap on the market. SOLUTION: In this tap for screw cutting, a final shape of a female screw is machined by a non-synchronous system in which feed of the tap is not synchronized with rotation of a main shaft to perform screw machining within a mold of a progressive press die. A round chamfering surface 6g is formed by performing chamfering for a ridge line edge part of a peripheral direction in which a land surface 6a of a top part and flank surfaces 6b on both the sides are intersected for a trapezoidal blade part 6 formed on a screw thread of a biting part 3 of the tap. As a result, the "burrless screw machining" without generation of burrs (hair-like burrs) is realized on a machining surface of a workpiece. COPYRIGHT: (C)2005,JPO&NCIPI