| 摘要 |
PROBLEM TO BE SOLVED: To provide a boring tool which effectively prevents cut pieces from falling. SOLUTION: The boring tool is equipped with: a cylindrical hole cutter 21 having a cutting edge in a lower end; a drill 30 arranged at a center of rotation of the hole cutter 21, protruding downward to the hole cutter 21 and rotating together with the hole cutter 21; and an engaging member 31 provided in an intermediate part of the drill 30 so as to freely protrude and retreat relative to an outer peripheral surface of the drill 30, inserted into a small diameter hole formed by the drill 30 to protrude outward and engaged with the cut pieces cut by the hole cutter 21 from a lower side. COPYRIGHT: (C)2011,JPO&INPIT
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