Disclosed is a compound harmonic gearbox having: a first ground gear and a second ground gear being interconnected about a stationary shaft to form a housing, wherein only the first ground gear includes gearbox mounting features; an output flange partially encased within the housing; a flex spline within the housing that drives the output flange; a wave generator within the housing that drives the flex spline; an input shaft with an input gear that drives the wave generator, the input shaft extending through the first ground gear, wherein the output flange is configured to rotate completely around the stationary shaft by rotating the input shaft.