Abstract: A precision system for moving a tool with very small increments with respect to a frame including at least two micrometer drive mechanisms each comprising a screw spindle and a cooperating nut and each provided with an intermittently driven worm and worm wheel. The tool is borne solely by the micrometer drive mechanisms that are supported in the frame. In a preferred embodiment is of each micrometer drive mechanism the worm wheel mounted on a spindle, one of said worm wheel and spindle being connected to the screw spindle and the other to the nut.