| 摘要 |
<p>The present invention relates to a drill body for a drill having a rotational axis, comprising an inner pocket (20) formed adjacent to the rotational axis at a proximal end of the drill body and an outer pocket (20') formed further away from the rotational axis than the inner pocket at the proximal end of the drill body. Each of said pockets comprises a first wall (51, 61, 51", 61") facing the workpiece, a second wall (51', 61', 51"', 61"') substantially perpendicular to the first wall and disposed adjacent to the rotational axis of the drill body, and a bottom surface (71, 71'). Each of the first wall and the second wall comprise a respective flat lower side surface (61, 61', 61", 61 "', 61"") adjacent to the bottom surface and a respective curved upper surface (51, 51', 51", 51"', 51"") extending from the lower side surface. The first walls of the inner and outer pockets include identical surface shapes while the second walls of the inner and outer pockets include identical surface shapes.</p> |
