| 摘要 |
<p>A metal cutting drill (10) with two replaceable cutting inserts (30, 31) which are positioned to cut the full circumference of a hole during each one-half revolution of the drill (10). Each insert is triangular and includes an active cutting edge having a curved corner to enable the insert (30, 31) to cut near the center of the hole. Each insert (30, 31) may be inverted and indexed in order to bring an alternatively usable cutting edge into active cutting position. By virtue of the inserts (30, 31) being triangular, the curved corners on the cutting edges of the two inserts (30, 31) may be positioned relatively close together and yet sufficient space is left between the inserts (30, 31) to enable the drill body (13) to be relatively thick and strong. <IMAGE></p> |
