OldBellows

Sheet Iron will work for the blades, just try to get the blades as balanced as possible. As for the gearing, I have seen several blowers that have been adapted by using one of the old hand cranked grinders. These are still readily available at most flea market/junk shops. I have seen the fans and case mounted directly to the gear box, and also a pulley could be used to the existing one on your blower. Show us what you come up with.

If thats the original Lincoln Anvil then I have a really great deal. I have the original Pigeon from Pigeon Forge Tenn. I'll let go for about $25,000

Check out Dan's version of a retort. I built one on a smaller scale and it works like a dream. http://www.twinoaksforge.com/BLADSMITHING/MAKING%20CHARCOAL.htm Pine charcoal burns faster but it doesnt leave as much ash, and not nearly as many 'fleas' when you forge with it.