| 摘要 |
PROBLEM TO BE SOLVED: To provide a drill maintaining high rigidity of a drill body, without influencing the depth of a formed machined hole by the shape of the drill body and stably supplied with a cutting fluid from the outside. SOLUTION: A columnar part 16 with an outer diameter almost equal to the outer diameter of a shank part 15 and smaller than the outer diameter of a cutting edge part 11 is provided between the cutting edge part 11 and the shank part 15. A chip discharge groove 12 provided at the outer periphery of the cutting edge part 11 is formed to be cut upward at the columnar part 16. COPYRIGHT: (C)2005,JPO&NCIPI
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