The box taps is a special external tool cutting thread and fishing externally from dropped object such as tubing, drill pipe.

母锥是一种专门从油管、钻杆等管状落物外壁进行造扣打捞的工具。

This paper discussed the methods about cutting thread on nc Lathe. The cutting errors was analyzed. The program about cutting thread and the notices in cutting process were concluded.

本文首先介绍了螺纹数控切削的编程方法，并就其对加工误差的影响进行了分析，最后根据实际工作总结出数控车床螺纹切削编程及加工时的注意事项。

Doug Cutting has posted on the topic of thread safety a couple of times.

Doug Cutting曾几次发表线程安全性的主题。