Patent ID: 7686105

Claim:
A drill comprising: a main body; and a high-hard tip attached to a front end of the main body, wherein the tip has a width greater than a diameter of the main body, an axial line of the tip is shifted in a widthwise direction from an axis of the main body, the tip is formed with a cutting portion on a front end of a base portion attached to the main body, the cutting portion has an angular form whose vertex is a cutting point, the cutting point is shifted in the widthwise direction from the axis of the main body, the tip has side cutting edges on both sides of the cutting portion, the side cutting edges protrude outward from a periphery of the main body, one of the side cutting edges has a greater protruding amount than the other, and the side cutting edge having the greater protruding amount has a smaller height than the side cutting edge having the smaller protruding amount.