Knowing how to sharpen a tool has been around for centuries.
The basic principle is to find a material which is abrasive and harder than steal.
We have all seen films with blacksmiths hammering away at a new sword or axe, but how did they get them sharp?
Going back to the beginning, humans made tools out of the materials laying around, for example, animal bone and flint.
As time went on, we learn to use materials such as metal which got blunt, but could be resharpened.
A grind stone was developed to bring the natural resource of stone into a workshop environment.
A grind stone was an abrasive stone, normally some form of sandstone. It would spin round, powered by foot, water, wind or horse, while a person held their axe, knife, or other implement they wanted sharped against it.
The Wandering Albatross 