Explanatory notes
… mixers’ grindstones). (2) Grindstones for sharpening cutlery, tools, etc. , and designed for mounting on hand, … of metals, stone, glass, plastics, ceramics, rubber, leather, mother of pearl, ivory, etc. Except for some … sodium silicate, cement (especially magnesian cement) or less rigid cementing materials (such as rubber, shellac or …