RESTORING METHOD FOR CUTTING EDGE OF COATED DRILL

PROBLEM TO BE SOLVED: To solve the problem wherein when a coated drill provided with a hard film on the surface repeats restoring the cutting edge by regrinding and the recoating of the hard film after regrinding, crack and film peeling of the hard film and roughness of the flute surface are easily generated to increase the rotating torque and raise the possibility of breakage. SOLUTION: The coated drill having the hard film 7 on the surface of the body 1 is reground to regenerate the cutting edge 2, and then, the hard film 7 is recoated within the range from the tip end of the body where the length L from the outer end of the cutting edge is 1 mm or more, 10 mm or less, and preferably, 1 mm or more and 3 mm or less. COPYRIGHT: (C)2006,JPO&NCIPI