| 摘要 |
A spade drill characterized in that the slotted blade clamping end of the holder has oppositely beveled end surfaces which are perpendicular to the respective side faces of the blade and which are at an angle less than the angle of the respective cutting edges of the blade to define convergent passages of right angle cross section for funneling or tracking chips to diametrically opposite obtuse angle cross section longitudinal grooves in the holder. |
