| 摘要 |
The present invention concerns a twist drill comprising a shank and a cutting portion which is defined by the axial length of the chip flutes and which is at least partially coated. To provide a twist drill having the aforementioned features and a process for the production thereof, which on the one hand have very good properties in terms of service life and chip formation or chip transport, but which on the other hand are also highly suited for reconditioning including coating, in accordance with the invention it is proposed that the cutting portion has substantially over its useable length a first coating, wherein there is provided a second coating which is different from the first coating only in the region of the tip of the drill and which extends over an axial length which corresponds at a maximum to twice the nominal diameter of the drill. |
