| 摘要 |
The drill head (3) has an apron with debris removal grooves (16A, 16B) on the outside, which extend in the axial direction of the drill crown (1), as do the bars formed in between the grooves. A coupling is provided for connecting the drill crown to a drill rod. At least some of the ends of the bars facing away from the drill head are configured as return teeth (18), each one of which has a cutting edge (19A, 19B). At least some of the bars have a chip surface (31) and a release surface (30), the angle between these two surfaces being no greater than 100 deg. An Independent claim is also included for a method for making the drill crown. |
