Badfrog, I cannot take credit for the design. It comes from a company by the name of Southern Yankee in the state of Indiana. The cook drum is 3/16 and the fire box 1/4 inch regular steel. I used as much stainless steel in the cooking chamber as I could. the shaft for the rotisserie, the deflector heat shield,the couplers to hold the wheels to the shaft,and the trays will all be stainless steel. Grainger Company has a gear reduction motor made by Dayton that is a two RPM motor. The motor runs about three hundred dollars. It will be coupled to the rotisserie shaft with gears and chain drive. Tractor supply has all the gears,hubs,and chain to make the connection.
There are three rods that run the length of the fire box. One for air inlets,one to control the heat and smoke to the cooking chamber,and one for the three doors to dump the ashes. The rod runs through two split spools to allow for heat expansion. The spools are welded to the bottom of the fire box. The ash doors are 1/4 inch steel,and are welded to the shaft. All were closely fitted,but not so tight to bind when heated. The dump doors are one inch bigger than the openings in the fire box. I believe they will seal adequately.
There will be a four inch stainless steel tube that runs the length of the fire box,and extends about five inches outside the box. It will have a fill neck with a cap on the top. The steam generated will get to the cook box via four SS 3/8" tubes. One last thing I hope to do is run a inch and quarter pipe the length of the fire box with a forced draft outside the box. The fan will be controlled by a high low thermostat. There will be a probe in the cook chamber to control the thermostat and fan. The pipe will have holes in front of each charcoal basket.
Almost forgot the pipe burner to get the fuel started. There will be three baskets on legs for the charcoal to go in.
Enough for now I will keep you all posted on the progress of the build.........Hutch