| 摘要 |
<p>A drill bit for the working of metal has a center pilot tip that transforms into straight cutting edges extending towards the outer periphery of the bit. Each cutting edge forms a cutting angle of 1-20° with a reference plane oriented perpendicular to of the drill axis. Each a cutting edge is inclined in a radially inward and axially rearward direction toward the drill axis. The center tip forms a pilot point angle of 90±2° and a has base that takes up 23-45 percent of the total diameter of the cutting section of the drill bit. The tip has a tip angle of 90±10°.</p> |
