| 摘要 |
PROBLEM TO BE SOLVED: To provide a tapping screw capable of being smoothly screwed into even to a wall backing material made of a thin steel sheet. SOLUTION: A screw thread 4 is provided at the outer periphery of a straight shaft 1. A lead-in cutting edge 5 having triangular cross section is formed at the outer periphery of a tip part of a circular cone-shaped part 2 provided at a tip of the straight shaft 1 to increase biting property of the tapping screw for the wall backing material 10 made of the thin steel sheet so that the tapping screw is smoothly screwed into the wall backing material 10. COPYRIGHT: (C)2007,JPO&INPIT
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