? on mothers burner

[pigpen52]

what is the purpose of using a cast iron skillet for the top part of the burner?   can it be just steel (like a brake drum)?  from what i read, it looks like you drill holes in it, and the middle plate....should these holes be offset from each other?

[techdif]

what is the purpose of using a cast iron skillet for the top part of the burner?   can it be just steel (like a brake drum)?  from what i read, it looks like you drill holes in it, and the middle plate....should these holes be offset from each other?

I think the cast iron is what the builder had available at the time.  I've seen examples on the net using thinner steel pans.  I went bat scat crazy on the drill press with mine and drilled each piece separately.  Unfortunately mine burning way to rich at the moment (only had one test fire so far) but I think this is due to my not fully forming the preheater.  Personally I would shy off the brake drum.  What if the drip ended up falling through a lug hole?  Could it cool the mid plate below ignition temp?  Just a thought.  From watching it burn I do think the pan diameters are very important to the design in allow the flame to flower   out of the burner.  good luck