| 摘要 |
PURPOSE:To bore through a fiber reinforced complex material with smooth working face while preventing the burr, crack, etc. CONSTITUTION:A groove section 3 is provided in the outercircumferential face of a drill 1 from the edge 5 to the shank section 2. Main cutting edge 7 is formed at the portion of the groove section 3 where the inner face and the leading edge face 4 will cross, while a clearance groove 10 having one edge coupled to the outercircumferential face is provided in the leading end face 4 and a cutter 9 is provided at the section where the inner face and the outercircumferential face of the clearance groove 10 will cross. Consequently even when fiber is contained in a material to be worked, the cutter 9 will cut the fiber while the main cutter 7 will cut the material to be worked together with the fiber resulting in the prevention of the burr and the crack. |
