A flap wheel grinding machine cools the cutting edge with air during the grinding process. The flaps have the effect of a fan, thereby reducing the risk of overheating.
The knife is pressed lightly against the abrasive belt, a few times for each side of the blade. The grinding angle is 20°. Knives are always properly ground if there is a wire edge or burr. This burr must be ground off on the polishing wheel.
In order to optimise the sharpness of the blade, a manual sharpening tool or a polishing steel is used after the grinding cycles to position the edge or to hone it further. The blade will be sharpened perfectly after a few strokes.
For this reason it is necessary to go through two work processes even withmachine grinding. After the first grind, polishing or sharpening paste is applied to the polishing wheel. A gentle pressure is exerted as the blade is then passed over the polishing wheel at a more acute angle. This polishes away the ground burr. This process is repeated until the burr has completely disappeared.
via Giesser Messer