The TORMEK SuperGrind stone has been developed to run at low speed in water. It is ceramically made (sintered at high temperature) and contains grains of aluminium-oxide. The SuperGrind stone grinds very effectively and gives a fine finish to the tool. It quickly grinds large tools for example plane irons, axes, scythes and even HSS steel. The grit rating is 220 and the grain size is 0,06 mm (0,0024"). The SuperGrind stone can be graded with the TORMEK Stone Grader SP-650 to a finer surface corresponding to 1000 grit suitable for fine grinding/sharpening. The outside of the SuperGrind stone has a depressed centre and a machined flat, smooth surface for flattening the back of plane irons and wood chisels. The large diameter 250 mm (10") leaves a smaller hollow shape on the bevel compared to a smaller dry grinding wheel. The large width, 50 mm (2"), gives you a generous surface to work on with your tools.