| 摘要 |
A drill, including: a substantially columnar drill holder including, at a front end portion thereof, a first insert pocket and a second insert pocket formed closer to the outer periphery of the drill holder than the first insert pocket; a first insert which is attached to the first insert pocket and includes a first cutting edge at an intersection of an upper face and a side face; and a second insert which is attached to the second insert pocket and includes a second cutting edge at an intersection of a upper face and a side face. The first insert pocket is located passing through a central axis of rotation of the drill holder. The second cutting edge has a concave shape when viewed from the front end side of the drill holder, and has a curved line at least a part thereof. |
