The rough edge of a file is cut with a series of sharp cutting edges known as ‘teeth’.
As the DIYer pushes the file along the material, applying light pressure, these teeth slice into it one after another to wear it down to a roughly flat surface.
In this way, files work through ‘abrasion’, a repetitive process that involves rubbing something rough against a piece of material to smooth it down.
This is the same concept as using a rough piece of sandpaper to smooth the edges of a piece of wood.
