| 摘要 |
PROBLEM TO BE SOLVED: To provide a gun drill, having excellent cutting performance, remarkably increasing the cutting speed as compared with the conventional one, attaining high deep hole drilling efficiency, remarkably extending the life of a cutting blade, and decreasing the frequency of regrinding for reuse especially in the case of a small-diameter. SOLUTION: In this gun drill, a cutting head 3A having a coolant discharge port 30 communicated with a coolant supply passage 12 at the tip face 3a is mounted on the tip 1b of a hollow shank part 1 having a chip discharge groove 11 having a V-shaped section along the longitudinal direction on the outer surface and taking the inside as the coolant supply passage 12. A cutting blade part 32 of the cutting head 3A is formed of cemented carbide W, and guide pads 5A, 5B brought into sliding contact with the inner periphery of a cut hole are formed of material of a different kind, which has higher hardness than the cemented carbide W. COPYRIGHT: (C)2007,JPO&INPIT |
