| 摘要 |
PROBLEM TO BE SOLVED: To provide a self-tapping screw having improved initial biting performance, and a manufacturing method thereof.SOLUTION: A self-tapping screw includes a head part 1 and a shaft part 2 suspending from the head part 1. The shaft part 2 comprises a cylindrical shaft part 2a right below the head part, and a truncated conical shaft part 2b continuing to the tip of the cylindrical shaft part 2a. A plurality of first male threads 3a is formed in the cylindrical shaft part 2a, a plurality of second male threads 3b continuing to the first male thread 3a is formed in the truncated conical shaft part 2b, and a biting surface 4 having an irregularity form is formed at the top part of each second male thread 3b.SELECTED DRAWING: Figure 1 |
