The DiamondCore Tools 8" Grinding Disc on a 12" Bat features a 7000 hardness rating. This makes it a higher hardness rating than the silicon carbide abrasives that are rated at 2400 hardness. If you're looking for a grinding disc for heavy glaze or high-fired clay removal, choose the 60 grit coarse grinding disc. The 120 grit medium grinding disc is perfect for general purpose and pot leveling. For smoothing, check out the 240 grit fine grinding disc. AKA Diamond Grinding Bat, AKA Potsavers.
*Technique Note: Always use water, high speed, and gentle pressure... "Let the diamonds do the work." Overheating the tool will greatly decrease its lifespan.