| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a center drill bit improving the cutting capability and machining speed of a center drill and reducing cost and machining time. Ž<P>SOLUTION: This center drill bit includes a drill bit body 1 and a center bit 30. The drill bit body 1 has a blade 20 provided with a center cutting edge rest 21. The center cutting edge rest 21 is formed with a screw hole 221. Pin holes 222 are provided on both sides of the screw hole 221. The halves of the pin holes 222 are positioned on the center cutting edge rest 21, and positioning pins 23 are fitted into the pin holes 222. The center cutting edge rest 21 has parallel straight sides 33 on its both sides. Each of the parallel straight sides 33 is provided with an oblique side surface 212 connected to a center positioning groove 213 and gradually narrowed. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
