例如，锥螺纹、梯形螺纹、三角螺纹等。

For instance, awl thread, ladder-shaped thread and triangle thread etc.

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在螺纹材料、尺寸、载荷都相同的情况下，三角形螺纹牙所受的剪应力最小，断裂载荷也比梯形螺纹和矩形螺纹高。

In the same material, dimension and load circumstance, the cut stress of the triangle thread is smallest. Its rupture load is higher than the echelon and rectangle.

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使用的刀具外形必须正好与要切削螺纹的轮廓一致，即三角形刀具必须用于三角形螺纹等等。

The form of the tool used must exactly coincide with the profile of the thread to be cut, i. e. , triangular tools must be used for triangular threads, and so on.

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