Aluminum Oxide 6x3/4x1 Wheel 150grAluminum Oxide Grinding Wheels are the accepted standard for sharpening high speed steels and high carbon steels, as opposed to conventional grey, hard, slow cutting wheels, which tend to burn tools as the grinding surface becomes dull and glazed. Our Norton Aluminum Oxide (AO) White Wheels are made of granulated aluminum oxide with a vitrified white bond that permits the grains of abrasive to wear off, thus providing a consistently fresh grinding