| 摘要 |
PROBLEM TO BE SOLVED: To ensure sufficient fracture resistance to a large cutting load, cutting resistance, and welding.SOLUTION: An insert for a drill is detachably attached to a tip of a drill body that is rotated around a shaft line. A polygonal face of a polygonal plate-like insert body 1 is a rake face 2, and a side face disposed around the rake face 2 is a flank face 3. A cutting blade 4 is formed at an intersecting ridge line part of the rake face 2 and the flank face 3. In the cutting blade 4, a honing face 9 which gradually protrudes from the flank face 3 toward the rake face 2 is formed at a first cutting blade part 4A that is continuous to at least one end of the cutting blade 4. The honing face 9 comprises a first convex surface part 9A continuous to the rake face 2 and a second convex surface part 9B continuous to the flank face 3. In a cross section perpendicular to the cutting blade 4, a curvature radius R1 of the first convex surface part 9A is larger than a curvature radius R2 of the second convex surface part 9B. |
