| 摘要 |
PROBLEM TO BE SOLVED: To provide an annular cutter capable of improving the discharging efficiency of chips produced by cutting. SOLUTION: A first cutting blade 3 and a second cutting blade 5 are alternately arranged at a predetermined internal in the circumferential direction of a bottom part of the annular cutter having a cylindrical body, a knife edge 4 of the first cutting blade is formed as an inclined face directed to upper sides of both ends in the width direction from a vertex P1 positioned at an outer peripheral side with respect to a central part in the width direction of the cutting blade, a knife edge 6 of the second cutting blade 5 is formed as an inclined face directed to upper sides of both ends in the width direction from a vertex positioned at an outer peripheral side with respect to the vertex of the first cutting blade, further plural inclined faces 6a, 6b discontinuously formed by stepped parts, are formed on the inclined face at an inner peripheral side from the vertex, and the knife edges of the first cutting blade and the second cutting blades are mounted in a state that the stepped parts 7 formed on the inclined face of the knife edge of the second cutting blade intersects the inclined face 4b at the inner peripheral side of the knife edge of the first cutting blade in a front view.
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