3M High Performance Vitrified Grinding Wheel 91VN is a bonded wheel featuring a mix of special white aluminum oxynitride, white alumina and 3M Precision-Shaped Grain. This blend of minerals is optimized for roughing and finishing process steps while grinding gear parts in the automotive industry, e.g. light vehicles. It delivers high performance, long life and perfect profile and surface quality.Optimized Grain Mix These 3M High Performance Vitrified Grinding Wheels 91VN feature a blend of white aluminum oxynitride, white alumina and 3M Precision-Shaped Grain. This unique mix delivers a number of advantages in gear grinding operations: Enhanced profile retention Stable profile quality Lower mechanical deformation of workpieces Excellent surface finish quality Grains prevent metallizing, helping to stabilize and monitor temperature-sensitive grinding processes, reducing heat and ensuring thermal damage to workpieces is virtually non-existent Provide self-sharpening, early chip formation, and reduction of chip cold welding High thermal stability during grinding process High stock removal rate reducing grinding operation cycle time