| 摘要 |
In a rotary drill, the drill is provided with at least one groove, which has a center lying on the axis of rotation of the drill. The two end points of the groove define a groove width, and the drill is provided with two or more cutting edges. Two cutting angles are defined. The groove has a left side and a right side. The rotary drill can be used in a rotary drilling machine. The drill can be provided with a drill bit. |
