| 摘要 |
The present invention relates to a twist drill for metal cutting made of solid cemented carbide including helical chip flutes 2 extending through the entire body or a part thereof, a shank 3 to be secured to a rotary spindle, two main cutting edges 5 and two leading edges 7. If the leading edges 7 have a larger edge radius than that of the cutting edges 5 an unexpected increase in tool life has been obtained. The invention also relates to a method of making such drills and the use of such drill for drilling in steel and stainless steel. |
