| 摘要 |
<p>A drill bit comprises a shank defining a longitudinal axis. A cutting head is formed at one end of the shank. At least one cutting edge and a centering point are formed on the cutting head. The shank and a portion of the cutting head are formed of a first material. The cutting edge, centering point and a portion of the cutting head are formed of a second material. A weld joins the first material and the second material. A first blank is welded to a second blank. A cutting head is milled into the first blank and second blank such that the cutting head is formed of the first material and the second material.</p> |
