| 摘要 |
<p>The drill has at least one swarf groove (1) and at least one web (2), and an internal cooling channel (3). The minimum wall thicknesses between the cooling channel (3) and the external surface (7) of the drill, between the cooling channel and the swarf carrying surface (5) and between the cooling channel and the surface (6) carrying no swarf lie in a region between lower and upper limits which depend on the diameter of the drill.</p> |
