| 摘要 |
PROBLEM TO BE SOLVED: To exhaust chips generated when a work is cut by the second cutting edge, to the outer side of a groove easily. SOLUTION: At the tip of a cutter main body formed in a cylindrical form, the first and the second cutting edges 13 and 15 are provided. The edge height of both ends 15a and 15b in the width direction, at the second cutting edge 15 is made in a value smaller than the edge height of both ends 13a and 13b in the width direction in the first cutting edge 13. Furthermore, at the center in the width direction of the second edge 16 provided at the tip of the second cutting edge 15, a plane part 17 extending linearly is provided, and chips cut out from the bottom surface of a groove by the second edge 16 are made in a band form by the above plane part 17. As a result, positions of both ends in the width direction of the chips are separated, and even though the chips are squeezed to the bottom surface of the groove, they are hardly caught to the groove. |
