worm-wheel hob thread

例句：

1. 1. The engineer used a worm-wheel to drill through the rock.
   工程师使用一个螺旋钻头钻透岩石。
2. 2. Thescrew-threads on the bolt wereperfectly aligned.
   螺栓上的螺纹完美对齐。
3. 3. The worm-wheel was designedto be easy to use and maintain.
   螺旋钻头设计得易于使用和维护。