Contact wheels not only come in different diameters, but also width, durometer, and serrate or plain. Most makers I know grind on a 2" wide 8 or 10 inch wheel. Durometer refers to the hardness of the rubber, the higher the durometer the harder the rubber. Common durometers being 70 to 90. The harder the rubber the more aggressive the wheel will cut. Serrated wheels cut even more aggresive than a plain wheel. If you want to do heavy stock removal and to do great finishes you will need to have two wheels. A serrate is necessary for heavy stock removal, but won't give a good finish when you go higher than a 220 grit,a 70 durometer plain surface wheel is great for finish work, and OK for stock removal. I do my profiling and initial grinding with a 1X 10" serrate 90 durometer wheel, and finish work on a 1X10" 70 durometer wheel. Hope this helps.
Ted
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