The inner surface at one open end of the plastic layer has the thread, and the thread on the plastic layer is connected with the thread on the metal insert.
2
在工具和管子的两端安装带螺纹的接头将工具或管子连接起来。
To connect tools or tubulars by assembling the threaded connections incorporated at either end of every tool and tubular.
3
固定螺纹连接部位的一端,以便在转动另一端时上紧螺纹。
To hold one end of a threaded connection while the other is turned to make up the joint.