| 摘要 |
<p>A drill includes a main body (11) and a high-hard tip (12) attached to a front end of the body (11). The tip (12) has a width (W) greater than the diameter (D) of the body (11) and has an angular cutting portion. In order to form a hole having a greater distal end in a wall, the tip is attached on the main body (11) in such a way that a cutting point on an axial line of the tip is eccentrically shifted from an axis of the main body (11). The drill is inserted into a preliminary hole drilled beforehand and cuts a distal end of the preliminary hole to form a hole including an expanded distal end having a greater diameter (D). Thereby, the expanded distal end hole having a greater distal end can be formed that is capable of increasing the fixity of an anchor.</p> |
