| 摘要 |
<p>A twist drill bit (10) comprises a shank portion (12), a flute portion (14) containing two flutes (16) and a tip portion (18). The flute portion (14) defines a web, wherein the web has a predetermined web thickness (T) adjacent the tip which increases from the tip portion (18) in an axial direction along the drill bit at a uniform taper rate in the range of 0.5 to 0.071 centimetres per centimetre of flute length. A process of forming such a drill bit (10) is also disclosed. <IMAGE></p> |
