Updated 05-May-2020.
Mondo shtuff from around the internet, all about BELT SANDER!
My botty best at summarizing from Wikipedia: belt sanders may be handheld and moved over the material, or stationary (fixed) it consists of an electric motor that turns a pair of drums on which a continuous loop of sandpaper is mounted . belt sanders can have a very aggressive action on wood . they are usually used only for the beginning stages of the sanding process . sometimes they are also used for removing paints or finishes from wood belt sanders can vary in size from small handheld unit shown in illustration to units wide enough to sand a full 1.2 by 2.5 m (4-by-8 foot sheet) of plywood in a manufacturing plant . slack-belt sanding is commonly used in the manufacturing process of guitars and other medium-sized wooden objects . the machinist then exerts pressure to it to sander down specific areas each heat begins when a common switch or individual switches triggered by the racers energizes them . sanders of all shapes and sizes can go very fast or very slow, depending on the power of the motor