A true evolution in small disc grinding, PDQ cloth discs cost less than half the price of quick-change laminated cloth discs, while in many applications providing improved performance. A sturdy, reusable, steel mounting nut is pushed through the front of a plain disc with a center hole, forming a quick-change disc, which spins on and off a PDQ holder pad. The mounting nut sinks below the disc surface, so that it won’t touch the workpiece at any angle. Optional backup plates allow the user to choose the flexibility of the holder pad. PDQ holder pads are engineered to run at greater RPMs and more flexibility than any other holder. A PDQ Disc is a plain cloth disc with a center hole. As such its selling price is less than half of that of common quick-change discs, which require lamination and glueing on a throw-away button. Experienced PDQ users pre-mount several discs to the re-usable hubs, for efficient and cost-effective quick-change grindng. The PDQ Mounting System is also available for use with larger diameter (4", 4-1/2", 5", 7" & 9-1/8") resin fiber and cloth discs. The PDQ Mounting System Diameters Available     1-1/2", 2" & 3" Material Specifications Most Commonly Ordered   R145   By far the most commonly ordered material, it's used for grinding and finishing ferrous and non-ferrous metals as well as sanding hardwoods. Base adhesion and grain retention engineered for improved edge wear in effected sizes, products and applications.     Grain: Aluminum Oxide     Coat: Closed     Bond: Resin/Resin     Grits Normally Stocked: 400, 320, 240, 220, 180, 150, 120, 100, 80, 60, 50, 40, 36, 24* * for 24 grit, 1AX material is used   R205   High performance and long life zirconia alumina grain for deburring and grinding hard ferrous and non-ferrous metals, alloys and stainless steel requiring sharp cutting without heat build-up.     Grain: Zirconia & Aluminum Oxide     Grits Normally Stocked: 120, 100, 80, 60, 50, 40, 36, 24   R544   Sharp silicon carbide grain for dry grinding of glass, ceramics, plastics, fiberglass, rubber, leather and non-ferrous metals; finishing iron, bronze, brass and aluminum castings; satin finishing sheet metals.     Grain: Silicon Carbide     Grits Normally Stocked: 220, 180, 150, 120, 100, 80, 60, 50 Other High Performance Grades   SH   For deburring and grinding iron, steel and aluminum castings; heavy structural work; weld grinding on steels including stainless.     Grain: Ceramic     Grits Normally Stocked: 80, 60, 50, 40, 36, 24   ZH   For deburring and grinding iron, steel and aluminum castings; heavy structural work; weld grinding steels including stainless.     Grain: Zirconia & Aluminum Oxide     Grits Normally Stocked: 80, 60, 50, 40, 36, 24   23MX   Amended combination of grains cuts better, stays sharp, and lasts longer; grinding and cleaning welds; cleaning, smoothing and polishing ferrous and non-ferrous metals including stainless steel.     Grain: Aluminum Oxide & Ceramic     Grits Normally Stocked: 120, 100, 80, 60, 50, 40, 36   CW   Wet grinding glass or ceramics; dry grinding plastics, fiberglass, rubber, leather and non-ferrous metals; finishing iron, bronze, brass and aluminum castings; satin finishing sheet metals.     Grain: Silicon Carbide     Grits Normally Stocked: 600, 400, 320, 240, 220, 180, 150, 120, 100, 80, 60