NorKut 3" 24 Grit Zirconia Alumina Quick Change Discs (20 Pieces) (03656) by Norton. Remove irregularities and sharp edges in stainless steel, titanium and super-alloys with the NorKut coarse grit threaded hole quick-change polymer disc. Use the disc with quick-change mandrels on hand-held pneumatic grinders and drills for a variety of deburring and weld blending applications. A great choice for grinding automotive pinch welds and other difficult-to-access surfaces, this inflexible disc features a strong zirconia alumina grain attached to a tough, trimmable polymer backing for exceptional strength and longevity.