The Norton Aluminum 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 surface. Sharpening is faster with less danger of taking the temper out of the tool.