| 摘要 |
<p>The drill bit (1) has a cylindrical shaft with a pointed cutting head (5) vertically cut in half and in an obtuse angle back to the outer surface. The resulting pentagonal vertical area is provided with chamfered surrounding edges (12, 13, 14, 15) and has two downwards pointing main cutting edges (7, 8). All cutting edges (7, 8, 10, 11) can be used clockwise and anti-clockwise. The shavings are sucked into the system through a duct integrated in the center of the tool (1).</p> |
