Patent ID: 8727680

Claim:
A cutting drill comprising: a shank having a hole and configured to be gripped in a tool holder; and a drill body having a rod shape and locked into the hole of the shank, wherein the shank has an axis around which the drill body rotates, the drill body has a cutting-edge portion forming a tip portion of the drill body and a neck portion having a diameter smaller than a diameter of the cutting-edge portion such that the cutting-edge portion and neck portion are positioned in an exposed portion of the drill body exposed from the shank outside the hole of the shank, the cutting-edge portion has a first cutting-edge portion and a second cutting-edge portion formed between the first cutting-edge portion and the neck portion, and the first cutting-edge portion is contiguous to the second cutting-edge portion by a step portion such that the second cutting-edge portion has a diameter which is smaller than a diameter of the first cutting-edge portion.