German design & technology
The Scheppach grinding wheel stone is constructed so that with the Stone Grader it can be treated to change its property from fast grinding to fine grinding, i.e. sharpening.

The grading of the grindstone is done by pressing the fine side of the Stone Grader onto the grinding wheel stone, which makes it work as a fine grit stone (approx. 1000 grit). When pressing the coarse side onto the grinding wheel stone, the smoothened surface is returned to its normal condition (220 grit). This process does not place excessive wear on the grindstone and can be repeated any number of times.