DIY CNC 4 Awesome Machines You Can Build Today RF 45 and Clones These are Chinese made Bed Mills that are available from all sorts of places and in all sorts of variations They have a work envelope and rigidity similar to a Bridgeport but without the heavy knee so they re better suited to CNC projects Their biggest disadvantage is their spindle which is limited to 1600 rpm Plan on doing a belt drive conversion at some point