Gentlemen,
Around 1950 my father bought me a second hand treadle lathe. It was clearly for metal working, with top and cross slides, gears and a lead-screw. The flywheel was massive, but the flat belt either kept breaking or slipping off the pulleys. If you did manage to have your toe under the cast iron treadle, it was only the mass of the treadle which could clobber you. The linkage had been slotted for that very reason.
Unfortunately, the lathe was already knackered. The one-piece casting had split over the front bearing, and the three-jaw chuck was virtually useless.
Nevertheless, my school mate (a big lad who occasionally treadled for the headmaster), and I tried almost successfully to turn bits of wood in it.
Now here’s where you might find some additional benefit Gordon, the treadle pedal was wide enough for two.
For that extra tenth of a HP, you could invite a friend or SWAMBO to stamp on the pedal too.
Good luck,
Sam