| 摘要 |
A drill having an elongated body including a fluted land and a shank. The fluted land includes a plurality of radial grooves of reduced material thickness formed therein to the depth of the flutes. The grooves define discrete segments of the drill. Each segment has a facet which has the relief of a drill tip so that when the exposed drill tip becomes dull, the segment can be broken off at the notch exposing a successive, sharp drill tip. The drill can have the cutting edges coated with an appropriate protective material such as TiN, titanium nitride, titanium carbide, titanium carbonitride or any other appropriate coating material to improve cutting and preserve the edge.
|
