BUFF STICK
A buff stick is a piece of wood covered with abrasive paper. Similar to files, the cross-section of buff sticks (flat, round, triangular) depends on the profile of the component being worked on. They are typically used to smooth out the marks left by filing or machining or to carry out various decorative operations (satin finishing, removing file strokes, chamfering, etc.).
The abrasive on the paper can vary in type (emery or corundite, polycrystalline diamond) and in grit size. For precise use, the craftsman often shapes the tip of the buff stick with a knife to refine it or give it a specific form.