Although we saw the setup and motor run, I was skeptical until perspective backed up. That would be not so easy feeding by the carriage wheel due to rack & pinion. He's cranking the lead screw with longitudinal feed engaged, not really any different mechanically than a mill table. My temptation would be a gas cylinder or extension spring to keep backlash in one direction, his seems fine without it.
Great example of home engineering. HomemadeTools doesn't mean HandWorkOnly...just like this is not 'just' a hobby.