common_screw_element_有道手机词典

1.The screw is of modular design and its active part consists of two identical screws that are common screw element and left-handed screw element with shallow grooves.
其螺杆为积木式结构，通常由芯轴和装在其上的正螺纹元件和浅开槽反向螺纹元件组成。
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