Abstract: An improved stump grinding machine includes a turntable assembly on which the engine is mounted for rotation in a horizontal plane. Preferably, the turntable assembly includes a flat plate element on which the engine is carried. One rotatable ring of a turntable bearing is connected to the plate element for rotation therewith. The other ring of the turntable bearing is fixedly connected to the machine frame. A grinding wheel is located at the distal end of an arm structure pivotally connected to the plate element. The grinding wheel is driven from the engine by a pair of successive belt stages. Power between the belt stages is transferred at an idler shaft about which the arm structure pivots. The stump grinding machine includes a hydraulic system to effect horizontal and vertical movement of the grinding wheel as necessary during a cutting operation. The stump grinding machine may be a self-propelled machine, or may be configured for towing behind a vehicle.