The RF30 style round columns have a fine downfeed arrangement that amounts to a worm drive with a friction clutch on the big downfeed wheel shaft. It's fairly straightforward to add a powered drive onto the backside of the worm (a splined shaft to the worm through a magnetic clutch to a gearmotor, more or less). The result is a machine that works as designed manually, has minimal mods (two mounting holes and a hole in the worm housing), and is under electrical control for downfeed rate and start-stop.
HSM published a series in the 90s about improvements to the round column mills. Well worth looking up, most were really good ideas, well designed and implemented.