Orbital Sanders are also called finishing sanders, which comes in half-sheet and quarter-sheet models. A half-sheet sander allows for the sanding of large areas a bit faster and quarter-sheet model is known as a palm sander. The orbital sander is so named because of the action of the sanding pad. The pad moves in a tiny orbit, with a motion that is hardly discernible, so that it actually sands in all directions. The orbital sanders have a bag attached to catch all dust that is made from the sanding operation. It rotate a disk of sandpaper about 5″ in diameter at about 25,000 revolutions per minute.