| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of troubles such as chipping and breakage caused by chips entangling with or biting in a tap part which are generated in drilling a prepared hole by a drill part in drilling a female screw by a tap part. SOLUTION: A right-hand thread male screw 22 corresponding to a female screw to be formed is provided on the tap part 14, and a threading blade 24 cutting the female screw by being turned clockwise when viewed from a shank 16 side is formed along a twisted groove 18. The twisted groove 18 is twisted counterclockwise to the male screw 22, and a drilling blade 20 cutting a prepared hole by being turned counterclockwise when viewed from the shank 16 side is formed on a tip, and when the rotational direction is inverted between the prepared hole cutting by the drill part 12 and the female screw cutting by the tap part 14, chips generated in cutting the prepared hole are separated and thrown away.
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