I attempted one of these a few years ago from my own design, before I got a milling machine. Cut all the gears on the lathe -had to make a dividing head for that - assembled it ok but could never get it to turn freely enough. As I re call it had about 23 gear wheels on it of varying sizes, with 4 different shafts in order to get all the ratios somewhere near.
I gave up on it, I think it was as much lack of experience and as anything. I intend on having another go at sometime. I think I ditched my plans in disgust with the intention of starting from fresh next time.
So, good luck and keep us posted.