09-24-2015, 05:32 PM
Andy, I just came back to this site and looked at this thread again. I like the idea of two threaded rods synchronized together better than one threaded rod. I also think it might work better with a crank system instead of the expense of an electric motor. I'm thinking that you might take a look at a bike shop to see what it would cost for a couple of sprockets and a bicycle chain. I would also use a ball bearing at each end of each threaded rod. Make sure that both sprockets are identical in diameter and tooth pitch.