| 摘要 |
<p>[Solving Means] A ring with a cutting edge 1 is constituted by a ring portion 10, in which an insertion hole 11 allowing a drilling tool 40 to be inserted in the direction of an axis O thereof and having a circular shape in plan view, is formed, the ring portion 10 has a portion on the inner peripheral surface 10C provided with a recess 12 formed radially outward, a circular-arc arm portion 13, which extends in the peripheral direction from one peripheral end of the inner peripheral surface toward the other peripheral end thereof, in the opening edge of the recess 12 facing the inner peripheral surface 10C and is elastically deformable in the radial direction, is formed integrally in the ring portion 10, and the circular-arc arm portion 13 is pressed axially inward by a fastening screw 15 threadedly attached to a threaded attachment hole 14 which goes through the ring portion 10 in the radial direction, and is opened to a bottom surface of the recess 12.</p> |
