I had a Singer 99 with a bent shaft. I was able to put on a big spoked wheel and a hand crank - it worked 'ok' like that - just a bit wobbly. I do like to hand crank when I am camping. I even mended a 10 X 12 bell end wedge tent with it - I was sitting on the ground. It reminded me of the pic I saw of the Indian women sewing with hand crank sewing machine sitting on the ground out doors.
http://www.flickr.com/photos/floridamemory/2987124452/ None of them are me.