| 摘要 |
PROBLEM TO BE SOLVED: To provide a drilling screw for joining together sheet metals capable of sufficiently decreasing the occurrence of floating of a head part 1 by reducing an influence, exercised by burring, as much as possible and joining together sheet metals in a close adhesion state. SOLUTION: A screw for joining together sheet metals consists of a neck lower part 2 expanding toward a head part 1, a drum part 3 continued to the neck lower part 2, a tip parallel part 4 continued to the drum part 3, and a tip taper part 5 continued to the tip parallel part 4. A taper angle at which the root parts of the screw of the tip taper part 5 are interconnected is set to 22 deg. or below, the round of a tip part is set to 0.25 or less, and the height of the crest of a thread 8 is set in order of a drum part 3 a tip parallel part 4 > a tip taper part 5.
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