A little progress on the gantry crane. The plan was to use a couple of chain fall hand wheels to move the gantry and carriage with the chain fall around. As clocking of the gantry will be important (to keep it square), it will have a shaft spanning to the rails with sprockets that engage roller chain run the length of each rail. This way both ends are clocked to each other and it stays square.
Found a couple of hand wheels that can be used to turn that clocking shaft. These are nice big wheels, over 12" in diameter and should make moving the gantry a breeze.
However, over a week was spent trying to find chain for these NOS wheels. Nothing available locally, tractor supply, HF, or hardware stores had anything similar. Sizing the chain is pretty critical, and most chain sizes aren't close to what's needed for these old wheels.
After finally measuring some of the dimensions from an air hardening clay cast, ropes, and comparing to some existing hand wheel chain, two suitable candidates were located on line. Both appear to work, although the larger of the two isn't exactly the right pitch (slightly long), it would work. Had to order samples to verify fit.
I think the size 3/0 chain is actually the correct pitch. The 5/0 chain is very close, but slightly longer than needed. The nice thing about this chain is it's electroplated with zinc, so it will be a little cleaner to operate. Now to order the rest of the chain, and start prepping the the gantry build...
The joys of having 10 projects going at once!