Here's a couple pictures of my forge. It's cast iron, but as you can see, it doesn't have a fire pot. I have to build my fire quite high to to keep the iron from the air blast.

 

If I cut an opening could I set a fire pot in? I could weld one up or even use a brake drum. My problem is I don't know if it would crack the cast iron.

 

The blower I could lower with some threaded rod or use flex pipe.

 

I'm Northwest of Chicago and wonder if there's any members closeby.

Try filling the base with sand, ash or clay. You can then form a bowl to contain the fire . Depending on your fuel you at need 6-8" under the steel. You'll probably have the best luck with fire clay, or adobe (15-30% clay 70-85% sand or grog) some folks ad ash as a stabilizer.
You only want a small fire, say 3-6" across. Hard to work much more steel than that before it cools.
If you are using coal you can store fuel on the table, using water ad air to control the fire, dot work so well with charcoal.

You absolutely do NOT need a fire pot.

 

Forges like you have were designed without the pot, relying instead on the smith forming a pot/depression when he clayed the pan to prevent cracking.

 

The idea behind the pot is that it concentrates the burning fuel.  If you were to add an inch of clay to the pan, creating a bowl around the grate, you'd help to concentrate the fuel directly above the air source.

 

I would note that your grate isn't original and needs to have the holes drilled out a bit larger.  Those small holes will quickly fill with slag, choking the fire and making you work harder.

you can also stack dry firebrick around the tuyere to increase the height of the fire with out overwhelming the carrying capacity of the forge table.

Old Rascal,

 

a simple answer to your question; is No you do not need a fire pot ! However, with that nice of a forge you have,and as stated above I would line it with sand, clay, cat litter, brick, or something to help protect the cast iron table as well as keep it from cracking when it starts to cool down .

 

Sam

I have a flat cast rivet forge set up the same way and lined with clay, duck's nest depression around the air grate, fire bricks make whatever size fire pot I need. Since using my duck's nest forge I haven't been too excited about fire pots when using coal or charcoal.

 

Frosty The Lucky.

I'll ditto on what Mr Powers and Mr Frosty said- just do it with some firebricks- set em flat, or on edge for some more depth. Get clay in the base and form the ducks nest, then set the bricks as desired. Besides that, I wouldn't want to cut thru the cast pan. I did the brick thing with my stamped steel pan Champion and it served me well. I've upgraded to a fabbed forge with a cast fp, but still go back to the old Champion.

 

Steve