Belt grinding is the process of removing material from a piece of metal using a belt grinder, an electric machine that rotates a belt around two or more pulleys. Belt grinding is similar to the process of belt sanding, and the machines often look very similar. The crucial difference is that belt grinding is done to metal, while belt sanding is done to wood and other lighter materials. This process can be done several ways, and each way will have its own advantages and disadvantages. The amount of material removed from a piece will depend on the method used.
Wide belt grinding is one of the more common types of grinding methods available. This process often involves the use of a conveyor system that pulls the piece of metal to be ground past two or more grinding belts. The amount of material taken off of the piece can be dictated by several factors, including the type of belt, the speed of the belt, the distance between the belt and the piece, and the metal being ground. The first belt in the system is usually the coarsest and is designed to take off the most material. Belts positioned after the first one will become less and less coarse to remove less material and provide a smoother finish.
A backstand belt grinder is another common tool used for belt grinding, and it works especially well for smaller pieces of metal. The belt itself is positioned behind a platform on which the piece of metal can be secured or steadied, and one pulley, the higher pulley, is mounted at a 45 degree angle from the lower, larger pulley. The larger pulley rotates extremely close to the steadying platform so the user can press the metal against the belt rotating around the large pulley. Such grinders often feature plexiglass shields that can be lowered over the piece being fashioned during the belt grinding process to prevent debris and sparks from making contact with the eyes and face.
A tool very similar to a belt grinder is a bench grinder, which is a much smaller unit that is mounted to a bench or other solid surface. A bench grinder uses circular wheels instead of belts; the wheels can be interchanged, and the most common two wheels used are abrasive grinding wheels and wire wheels. The abrasive grinding wheel removes a significant amount of material when a piece is pressed against it, while a wire wheel will remove less material and provide a better finish.