Welcome Mark, To answer your questions secound hand wheels are hard to find for a good price and in good condition, Most of the time they will need a new shaft, new top wheel or aleast machined and most definitely need bottom lower anvils. There are new cast ones made in Sydney but they are very costly axp between $8000 - $10000 complete. All though im in Melbourne i do have wheeling machines and planishing hammers in stock.
You can tig or oxy weld the thanks but i prefer to oxy weld.
I use 005H34 sheet, which is half harden. I wouldnt advise you to use anything shofter for the tank.
