| 摘要 |
A trepanning drill having a drill axis of rotation (A) and comprising a drill bore extending rearwardly from a front portion thereof. The drill body has at least two cutting edges formed in the front portion thereof. Each of the cutting edges has a cutting external edge and a cutting internal edge. A circle passing through the cutting external edge of each of the cutting edges forms an external circle having a first diameter (D1) and a first center (A1). A circle passing through the cutting internal edge of each of the cutting edges forms an internal circle having a second diameter (D2) and a second center (A2). In an end view of the trepanning drill, the first center (A1) coincides with the drill axis of rotation (A), and, the second center (A2) is offset from the drill axis of rotation (A).
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