This is a sharpening stick.

Principle and correct use of sharpening stick;

The sharpening stick is made of "mild steel" and can be used to sharpen the edges of tools.

The role of a sharpening stick is different from that of a sharpening stone. A grindstone can be used to blunt tools, and a sharpening stick can only be used to sharpen the edges of tools and remove the subtle and unsmooth parts of the edges.