| 摘要 |
PROBLEM TO BE SOLVED: To safely perform drilling work by preventing breakage of a drilling edge when piercing a body to be drilled without a chip receiving cover probably constituting an obstacle to drilling work. SOLUTION: This drilling tool 1 drills a through hole in a wall material by a pair of independently projecting drilling edges rotated round a center shaft 4. The drilling tool includes: an abutting flange 23 inserted in a cut groove of the wall material cut by the drilling edge 7 in drilling and abutted on the inner surface of the through hole in piercing the wall material to prevent the drilling edge 7 from colliding with the inner surface of the through hole; and an abutting piece 24 abutted on the peripheral edge of the through hole of the wall material to prevent the drilling edge 7 from being pushed into the wall material more than fixed. COPYRIGHT: (C)2006,JPO&NCIPI
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