| 摘要 |
PROBLEM TO BE SOLVED: To enable a head part of a screw to pierce or to be buried in a wall plate material of plaster board or the like connected onto the head part of this screw. SOLUTION: A drilling tapping screw 12 has a head part engaged with a rotary tightening tool and a shaft part extended downward from the head part, in a lower tip end of the shaft part, a drill part is formed, from a base end side of the drill part over to the head part, a thread cutting and tightening thread ridge is formed. This head part 46 has a tip sharpened protrusion part 32, engaging part 45 engaged with the rotary tightening tool, and a flange part 34. The protrusion part 32 comprises a tip end cone-shaped first tapered part 32, shaft part 32b of fixed external diameter, and a second tapered part 32c continued thereto. By this screw 12, a framework member formed by a steel material is fixedly tightened, a wall plate material is connected to this framework, by striking a location positioning the head part of the screw 12 by a hammer or the like, the screw head part except the flange part is made to pierce the wall plate material, to be buried. In this way, the wall plate material is temporarily locked, and the location positioning the screw head part of the wall plate material is also prevented from being swollen.
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