| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw for building capable of preventing lifting or swelling of material in fastening of a calcium silicate plate or an equivalent building plate material, and a thin plate backing material side made of metal. SOLUTION: The screw 10 for building includes a shaft part 12 having a screw part 14, a drill part 16 disposed on one end in an axial direction of the shaft part 12, and a head part 20 formed on another end in the axial direction, having a recess 18 for screwing in the shaft part 12, and with a larger diameter than a shaft diameter D of the shaft part 12. The drill part 16 includes a tip 22 having a comparatively large predetermined tip angleθ1; a tapered part 24 having a tip angleθ2 smaller than the tip angleθ1 of the tip 22, connected to the tip 22, and gradually becoming larger in diameter toward the shaft part 12; a cutting edge 26 formed from the tip 22 to the tapered part 24; and a chip discharge groove part 30 discharging chips produced by cutting of the cutting edge 26. It fastens a building plate material W1 producing chips such as a calcium silicate plate, and a thin plate backing material W2 made of metal such as a thin plate backing steel plate. COPYRIGHT: (C)2011,JPO&INPIT
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