| 摘要 |
A tool support is provided for removably supporting a twist drill of high speed steel and a pair of indexable cutter blades of tungsten carbide. The cutter blades are triangular and provide three cutting edges about the periphery thereof, and the cutter blades are removably mounted on the tool support to enable selective indexing of the cutting edges to a cutting position. The cutting edge to be used is axially and radially stabilized in the cutting position by engaging edge and bottom portions of the blade in a pocket provided on the tool support. The tool support includes a channel adjacent each of the cutter blades defined by walls extending axially of the tool support in planes parallel to the tool axis and perpendicular to one another to optimize the available area for chip removal, and the entrance ends of the channels are provided with relief surfaces to promote the feeding of chips into the channels. A bore is provided in the mounting end of the tool support to receive lubricant, and a pair of lubricant passages extend through the tool support from the bore and open through the outer end face of the body portion between the channels therein. |
