| 摘要 |
A segmented orbital drill 10 includes a segmented portion 18 with a semi-finishing cutting portion 40, a plurality of finishing cutting portions 42 and a clearance neck section 26 between the segmented portion 18 and a shank 22, the semi-finishing cutting portion 40 having a different diameter 44 to the diameter 46 of the finishing cutting portions 42. The semi-finishing cutting portion 40 and finishing cutting portions 42 are separated by grooves 45a, 54b, 54c formed by a front wall 55 and a rear wall 56. The segmented orbital drill 10 may include a pilot 14 at one end of the drill 10. |
