STANDARD DIAMOND WHETSTONES Diamond whetstones are available in three grades: COARSE For dressing chipped and damaged cutting tools and for sharpening garden shears and axes. MEDIUM Ideal for rapidly sharpening wood chisels and plane irons prior to final honing. FINE For refining the cutting edges of chisels and plane irons and particularly suited to the honing of router cutters. Both the 150mm and 200mm whetstones are supplied in a crafted wooden box. Grit 180.