Sun gold Abrasives is an industry leading manufacturer of professional/industrial strength abrasive products. Having been in business for over 40 years they make only the best products at competitive prices. Most popular grits for glass: 60X: extra-rough, fast glass removal (mitered edge) 80X: rough, quick-contouring (auto glass edge) 120X: smooth, Seaming and polishing (desk top edge) 220X: extra-smooth, fine frosted finish (glass shelf edge) 400X: fine, satin finish (opaque edge) cork: polish, smooth luster finish. To break in cork belts, put them on the grinder with a tool rest in place. Using a Scrap piece of blade steel wear on that belt for a good 10 minutes. Be careful not to "break" the corners, or edges of the belt too aggressively, or all the cork and polishing media could peel off. Buffing compound can help make it easier to "fold" around the edge of the wheel. You do need to slightly break or round the corners of the belt around the edge of the wheel, however, but be careful not to overdo it. It is smelly and dirty for that 10 min, but it takes that long (10 min. By the clock) to break the belt in. A new cork belt looks like a 36 Grit belt, it's quite rough. When it's broken in it has some smooth spots and some valleys and starts taking on a smoother, slightly shiny appearance. Use the buffing compound during the "break-in." be advised that it takes some pressure, and time to do the job. You don't want to peel off cork, you are trying to just smooth out the surface of the belt somewhat.