Abstract: A machine stepper has a machine-supporting platform that normally stands on the floor by means of fixed support posts. A substantially rectangular frame is provided underneath this platform and can shift relative to it. This frame is constituted by a pair of generally parallel longitudinal members and a pair of generally parallel transverse members pivoted together at corners at each of which is provided a respective upright and vertically extensible leg. Two of the diagonally opposite legs pivot about respective longitudinally extending horizontal pivot axes and the other two legs pivot about respective transverse horizontal pivot axes. Cylinders are provided for horizontally shifting the frame relative to the platform so that when the legs have been extended to lift the posts of the platform off the ground these cylinders can step the platform horizontally and when the expansible legs are shortened it is set back down on the floor.