I welded up mine out of 1/2" plate. It has a 1/2" thick x 1" wide lip all the way around. Having this lip lets it just set in the hearth without being attached. Some will tell you to mount it flush so to make it easier to rake in fuel. I have not found it to be an inconvience to me. Make yourself a proper rake and I doubt that it will be a problem. Even with the fire pot 4" deep, you should have 3 or 4" of coke above the top. I have a slot cut in the lip around my hearth but not in the lip around the fire pot. This works well for me, but consider all options before you make a final descision,