Secondly there is error between the thread roll angles of thread rolling die and drill rod.

滚丝轮螺纹和钻杆螺纹的螺旋角有误差。

youdao

Secondly there is error between the thread roll angles of thread rolling die and drill rod.

滚丝轮螺纹和钻杆螺纹的螺旋角有误差。

youdao