Grinders and sanders use nearly the same methods to remove a small amount of material from the work piece. Both grinders and sanders generally come in two styles, benchtop models that are mounted on a workbench, and freestanding models that can be bolted to a shop floor. Grinding machines typically use an abrasive wheel to remove material. Since the work piece is held by the operator when grinding, one can be precise whe removing sharp edges, removing blemishes, and reshaping the piece. Surface roughness as a result of grinding is reduced as the grain of the abrasive wheel is increased, as is the amount of material removed while grinding.
Sanders, instead of using an abrasive wheel, use continuous belts driven by one or more drum wheels. Sanders allow for a larger surface to be worked at once due to the surface area of the belt. The belt's surface is coated in an abrasive grain material that, like grinders, can be changed depending on the finish quality desired.