QualityParts From Oregon That you can depend on. Blue grinding stone: Outer diameter: 10", Thickness: 1", Bore: 3/4"; Use with OregonĀ® 88-031 and 88-018 blade grinders; Rating: 2200 max RPM; 36 grit; ; Oregon Equipment Parts 88-049 Grinding Wheel 10 Blue 36 Gri