The rare and desirable infinitely variable-speed drive system with twin V-belt drive up to the miller. Manufactured by the "Master Electric Co." and called the "Speedranger" the drive offered speeds from 125 to 2250 rpm and was typical of those first made in the late 1920s with the variation in output speed being achieved by a pair of expanding and contracting V pulleys connected by a steel chain-link belt running in an oil bath . The unit was neatly designed and heavily built; a specially-made, cast-iron frame 2-speed motor was used (with an integral support bracket) mounted end-on to the speed changer; the  both units being fastened to a heavy metal plate slung, in the case of the 3C miller, beneath the bench. In order to make the unit suitable for as wide a range of applications as possible the position of the variable-speed pulleys were altered through a worm-and-wheel mechanism driven by a cable held within a flexible conduit.