triangular oil stone

例句：

1. 1.The triangular oil stone is used to polish the surface of the workpiece.
   三角形油石用于抛光工件表面。
2. 2. The triangular oil stone is a useful tool for grinding and polishing metal surfaces.
   三角形油石是一种有用的工具，用于磨光金属表面。
3. 3.The triangular oil stone is commonly used in industrial settings to remove scratches and imperfections from metal surfaces.
   三角形油石在工业环境中常被使用，用于去除金属表面的划痕和瑕疵。