Repairing the cutting edge of the drills used to pierce plugs.
We can distinguish three parts in it: a brass cone, a steel blade (with a variable opening) located on its side and a wooden handle.
We take the instrument by the handle, open the blade and introduce the cone inside the cylinder. Next, we press the blade against the edge of it and we simultaneously turn and press the sharpener. We repeat the process until the edge of the tube is sharpened.