| 摘要 |
The invention relates to a step drill, formed by the drill or holder (2) of a drilling tool (1), with flutes (3, 4) intended for chip disposal, at least one first cutting edge (5) provided at the tip, and also a step-drilling ring (10) which is firmly but releasably arranged on the drill or holder (2) and is provided with at least one second cutting edge (11, 12) (step-cutting edge) which is arranged at a certain distance from the first cutting edge in order to chamfer, countersink or counterbore the hole (5') drilled by the first cutting edge (5). The step-drilling ring (10) is provided with recesses (15, 16) which are arranged opposite the flutes (3, 4) and form chip passages (20, 21) with the latter. <IMAGE>
|
