| 摘要 |
A drill according to an embodiment has a cutting tip and a holder located on a rear end portion side of the cutting tip. The cutting tip has a first cutting edge and a second cutting edge located away from each other at a front end portion thereof, a first flute and a second flute respectively extending from the first cutting edge and the second cutting edge toward the rear end portion, a first side surface and a second side surface respectively extending from the first flute and the second flute toward a front side in a rotation direction, and a first constraining surface and a second constraining surface respectively extending from the first side surface and the second side surface in a tilt direction with respect to the rotation direction. The first side surface and the second side surface are asymmetric with respect to a central axis, and the first constraining surface and the second constraining surface are point symmetric with respect to the central axis in a front end view. |
