Flap discs are used for stock removal, grinding, blending, deburring, finishing and polishing. They are constructed with layered flaps mounted on a rigid backing. Flap discs mount directly on the sander or grinder with a through hole or threaded hub.
Coated abrasives can be used for most applications, from grinding to polishing. They consist of a thin layer of abrasive adhered to fiber, paper, cloth or rubber. Coated discs are normally used on angle grinders.
Non-Woven abrasives reduce undercutting and gouging of surfaces. They are frequently used in deburring, surface preparation and as a final finishing step.
Choosing the correct abrasive material for your surface can shorten work time, reduce cost, and prevent premature wear. Aluminum oxide, for example, is a great all-around abrasive material, while silicon carbide produces finer finishes on most surfaces.
Aluminum oxide is the most commonly used abrasive. Best-suited for general purpose deburring and blending, it is tough, economical and fracture-resistant. Commonly used on ferrous alloys, high-tensile materials, and wood.
Cooler-cutting and more durable than natural aluminum-based products, ceramic provides a sharp, high-purity grain. Commonly used for precision grinding of steels, hard alloys and exotic materials.
More durable than aluminum oxide, zirconia-alumina is best for medium- to heavy-material removal. The material grains constantly fracture to produce new sharp edges. Commonly used on carbon steels, aerospace alloys, nickel alloys, aluminum, cast iron, forgings and some stainless steels.
Grit (FEPA)
FEPA (Federation of European Producers of Abrasives ) is the European standard measurement for grit size. It differs significantly from ANSI at sizes finer than 200.
Use larger grits/coarser grades for removing more material over a larger contact area. Use smaller grits/finer grades where the final finish is important. The chart below applies to only ANSI grit sizes.
Flap discs are used for stock removal, grinding, blending, deburring, finishing and polishing. They are constructed with layered flaps mounted on a rigid backing. Flap discs mount directly on the sander or grinder with a through hole or threaded hub.
Abrasives 
