그라인딩(grinding), 버핑(buffing) 또는 날연삭 (sharpening)용 공구(회전통 장치를 위해 특별히 제작된 마모체(abrading?bodies), 예. 마모볼(abrading?balls) b24b 31/14; 연마 도구 b24b 33/08; 래핑(lapping) 장치 b24b 37/11) tools for grinding, buffing or sharpening (abrading-bodies specially designed for tumbling apparatus, e.g. abrading-balls b24b31/14; honing tools?b24b33/08; lapping tools b24b37/11) 