| 摘要 |
A drill bit 10 comprising a cutter 20 including a lead screw 21 and a spur 22, multiple flutes 40, and a shank 50. The cutter is provided with two symmetric surfaces each having a conic front and a wedge shaped side, the center of both symmetric surfaces being integrated into the spur. A section 231 overhangs the fluted land section 30 and is provided with a scraping surface 23 and a blade 24. An inclined surface 25 for expelling residual chips extends from the lead screw to the bottom of the cutter. |
