Drill

A drill that rotates around an axis, the drill comprising:

• a first flank face;
• a first thinning face provided rearwardly of the first flank face in a rotation direction;
• a second flank face provided rearwardly of the first thinning face in the rotation direction;
• and
• a second thinning face provided rearwardly of the second flank face in the rotation direction, wherein
• the first flank face includes
• a first front flank face portion, and
• a first rear flank face portion that is contiguous to the first front flank face portion, is inclined with respect to the first front flank face portion, and is provided rearwardly of the first front flank face portion in the rotation direction,
• the second flank face includes
• a second front flank face portion, and
• a second rear flank face portion that is contiguous to the second front flank face portion, is inclined with respect to the second front flank face portion, and is provided rearwardly of the second front flank face portion in the rotation direction,
• the second front flank face portion is contiguous to each of the first front flank face portion and the first rear flank face portion,
• the second rear flank face portion is contiguous to the first front flank face portion,
• when a ridgeline between the first front flank face portion and the first rear flank face portion is defined as a first ridgeline, and a ridgeline between the second front flank face portion and the second rear flank face portion is defined as a second ridgeline,
• a distance between the first ridgeline and the second ridgeline in a direction perpendicular to the first ridgeline as viewed in an axial direction from a front end toward a rear end of the drill is greater than 0 mm and less than or equal to 0.03 mm,
• a ridgeline between the first front flank face portion and the second rear flank face portion constitutes a first chisel region,
• a ridgeline between the first rear flank face portion and the second front flank face portion constitutes a second chisel region,
• a ridgeline between the first front flank face portion and the second front flank face portion constitutes a third chisel region contiguous to each of the first chisel region and the second chisel region,
• the third chisel region is provided at the front end,
• a ridgeline between the first thinning face and the first flank face and a ridgeline between the first thinning face and the second flank face constitute a first thinning ridgeline,
• a ridgeline between the second thinning face and the first flank face and a ridgeline between the second thinning face and the second flank face constitute a second thinning ridgeline, and
• a shortest distance between the first thinning ridgeline and the second thinning ridgeline in a direction perpendicular to the first ridgeline as viewed in the axial direction is greater than or equal to 0.04 mm and less than or equal to 0.10 mm.