***** EDIT ***** Please use safe methods when using galvanized piping around heat sources. At high temperatures, the zinc oxide plating can vaporize and cause metal poisoning. If you must use galvanized, the coating can be removed by soaking in a mild acid such as vinegar for several days and then mechanically stripping the outer layer.
1. Brake Drum (size as you feel appropriate) from local wrecking yard or neighbors unattended vehicle
2. Floor flange (size to fit brake drum)
3. T Connection (size to fit floor flange)
4. Nipples (both close, and long)
5. Nuts and Bolts (sized to fit flange)
6. Shower Drain Strainer
I picked up the brake drum at my local wrecking yard. $10 for self service and there was no shortage of loose ones scattered about for the choosing. I probably spent more time eyeballing potential new projects than I did choosing a body for my forge. I then stopped by my favorite Home Depot for the rest of the supplies. I picked up a 1" floor flange for the underside of my forge with a standard shower drain for the inside grate. Went with a matching 1"close nipple, 1" Tee and another 6" nipple for my air supply. Snagged some #10 nuts and bolts for the connections and headed for the house.