A robotic machining tool employing an endless machining belt is disclosed. The tool includes a front pulley and a rear pulley which guide the machining belt, a drive unit which turns the rear pulley, a spindle about which the front pulley is free to rotate, and two wheels which flank the front pulley and are mounted idly on the spindle of the front pulley. The two wheels have an outside diameter greater than that of the front pulley in order to roll over a surface to be machined and in order to define a machining distance between the machining belt guided around the front pulley and the surface to be machined.