| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure to prevent a fastening screw from being loosened, by faithfully matching a flat chip, an expanding slot and the fastening screw of a ball end mill to the screw precision. SOLUTION: In this ball end mill, a flat chip 11 is sandwiched and fixed by inserting the flat chip 11 having a cutting edges in an expanding slot 2 crossing the center part at the tip of a holder body 1, and a countersink 6 to be matched with the head part of a fastening screw 4 is provided in one divided half 3. A female screw 8 of the fastening screw 4 is provided in another divided half 7, a coned disc spring and a taper ring are mounted by ringing them underneath the head neck part of the fastening screw 4 and a tapered part corresponding to the slope of the tapered ring in the through hole 16 for the fastening screw 4 of the flat chip 11 is formed. The flat chip 11 is constrained on the bottom part of the expanding slot 2 by providing a slit 10 at a position shifted toward the divided half 3 on one side. |
