| 摘要 |
<p>The invention is particularly intended to reliably treat cuttings produced in a copy lathing. A solution means comprises the steps of forming a rake face in the polygonal surface of a tip main body in the form of a polygonal flat plate, forming a pair of cutting blades in the edges of the polygonal surface that respectively extend from the corners (C) thereof, the rake surface being inclined to be gradually recessed as it is spaced from the cutting blades, the land that is formed along the cutting blade being inclined at a smaller angle of inclination than the angle of inclination of the rake face such that it is gradually recessed as it is spaced from the cutting blade, the angles of inclination of the rake face and the land being reduced toward the direction in which it is spaced from the projecting end of the corner along the cutting blade, forming, on the rake face and spaced from the cutting blade, a main dot in the form of a convex surface on the projecting end side of the corner (C), and forming at least a pair of secondary dots in the form of convex surfaces at positions respectively spaced from the main dot along the pair of cutting blades.</p> |
