ball faced hexagonal nut

例句：

1. 1. The engineer useda ball-faced hexagonal nut to tighten the bolt.
   工程师用一个球面六角螺母来拧紧螺栓。
2. 2. The construction worker needed a ball-faced hexagonal nut for the project.
   建筑工人需要这个球面六角螺母来完成项目。
3. 3.The tool manufacturer produces ball-faced hexagonal nuts for various applications.
   工具制造商生产各种应用的球面六角螺母。