What's the name of the cutter of the grinder?

The grinding wheel grinder doesn't have any tools, but the tools are grinding wheels. Grinders use grinding wheels to process workpieces, and all kinds of grinding wheels are grinding tools. There are many kinds of grinding wheels used, some are disc-shaped and some are bowl-shaped. There is also a tool for grinding, that is, a diamond pen, which can be used to dress the grinding wheel of a grinder. Without a diamond pen, the grinder can't work.