broach grinder

例句：

1. 1. This broach grinder is very useful for sharpening knives.
   这个开刃机对磨刀非常有帮助。
2. 2. The chef needs to use a broach grinder to keep his knives sharp.
   厨师需要用开刃机来保持他的刀锋利。
3. 3. After using the broach grinder for a while, the knife feels much sharper.
   使用开刃机一段时间后，刀感觉更锋利了。