Abstract: A blasting wheel apparatus for treating the interior surface of a hollow workpiece. There is a superstructure which can be moved into position in vertical registry with the open top of the workpiece. The superstructure has hoppers for storing shot pellets to be used in treating the interior surface and a shot feed tube extends downwardly from the hopper so that its open end may be passed through the open top of the cavity and into the interior of the workpiece. A stabilizer structure is movable along the axis of the shot feed tube to engage the top of the workpiece and position the open end of the shot tube within the central area of the cavity in the workpiece. Slides project upwardly from the stabilizer into the support structure. In one embodiment the shot tube has a lifting element at its lower end to engage under the stabilizer so that the stabilizer may be lifted with the superstructure.