| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drill used for a highly accurate deep hole drilling performed on a resin material. <P>SOLUTION: A chip discharge groove 16d of a torsional semicircular line is formed in a drill 10d provided with a blade 12d at a tip side and a shank 30d at a rear end side. An outer peripheral surface of the blade 12d wholly forms a margin 14d. In the margin 14d, a sub-groove 20d is formed which is twisted in a direction reverse to the chip discharge groove 16d so as to revolve around a rotation shaft of the drill 10d and supplies a coolant to the blade 12d. The sub-groove 20d is divided by the chip discharge groove 16d to be opened in the chip discharge groove 16d. A coolant guiding groove 36d twisted in the same direction as the sub-groove 20d is formed in the shank 30d. <P>COPYRIGHT: (C)2013,JPO&INPIT |
