Abstract: An improved walk behind polisher and grinder is disclosed. The improved walk behind polisher and grinder provides a surface polishing machine capable of operation with increased directional stability and reduced dust accumulation to the essential internal components of the machine. The improved walk behind polisher and grinder includes a drive motor mounted on a frame. The drive motor rotates a central shaft, and the central shaft supports a belt pulley and a rotary housing. The belt pulley mechanically communicates with at least one pinion shaft through an endless drive. Each pinion shaft is mechanically engaged by an internal gear such that rotation of the central shaft causes the pinion shaft to rotate about their own axes in a given direction and to revolve around the central shaft in the opposite direction.