| 摘要 |
A screw having male thread for making a screw groove is provided to improve the fastening performance by forming the flanks of the thread at an optimum angle and by rounding a part between the peaks so that the byproducts can be accumulated in the rounded part. A screw includes male thread for making a screw groove(150). A flank angle between the flanks formed at both sides of peaks(110) of the thread is about 32 to 42°. A part between the peaks is rounded toward the axis of the screw to discharge byproducts generated when the screw groove is formed by the male thread.
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