For my first years as a blacksmith, I used a brake drum forge. Here's why and how I built a forge table to replace it.
The brake drum forge had flaws, one of which was that it did not have enough room around it to store ready-to-use fuel. With a coal fire, this would have been unworkable, but since I was using charcoal it was merely inconvenient (coke would have been worse than charcoal, but not as bad as coal).
Not having a table also meant that any piece longer than the size of the brake drum (about 10 inches, or 25 cm) needed to be supported. At first I held the other end, but soon improvised a small stand of scrap wood and a piece of steel (don't use wood for the supporter; it'll get scorched).
The ash dump and air valve were also unworkably flawed.
All these problems meant that I wanted to have a better forge. I knew I wanted to upgrade for a long time, but wasn't experienced enough to know what I would want to have instead. I bought a good solid cast iron firepot from Centaur Forge on a sale, so I had the most important specialized piece. I wanted to keep using charcoal, partly because it wouldn't annoy the neighbors as much as coal, and because it was fun to use the original blacksmiths' fuel. There were so many possibilities!
After using the forges at Vista, I finally had a better idea of how the small table forge should work. I wanted one, but didn't want to pay a few hundred dollars to buy one, and wasn't a skilled enough welder to weld one up. I did know how to rivet, though, and that was enough.
I found firebrick at a local masonry supply store, Bourget Bros. They had several kinds, and I got hard firebrick instead of insulating (this was a table surface, not a forge liner), and chose a size of split brick, which made them only a little thicker than the rim of the firepot. There was even a choice of colors. The other reason for choosing split brick instead of full thickness was that I wanted the table to be light enough to move.
I also picked up some one-inch angle iron for the frame and legs from a big box hardware store. I already had a good supply of 3/16" (5 mm) round head solid rivets and 16 ga. (1,5 mm) sheet steel, and some left over fire clay and hardware cloth.
The firebrick measured about 9" × 4-1/2" (22 cm × 11 cm) on the face, which meant the firepot fit comfortably in the space of one and a half bricks square. To figure out the table size, I put the firepot down on the concrete slab and placed the bricks around it. I laid out the angle iron frame to fit around the brick layout. I carefully measured the length of the sides, added the thickness allowance for the wall thickness of the angle iron, and cut the angle iron to length at a 45° angle with a hacksaw.
With this done, I would have welded the corners, but I didn't have the skill or equipment. Instead, I cut some right triangles from sheet steel, truncated the corners and filed the edges smooth, and bent them down the middle into a right angle. These would serve as braces to hold the corners together, and hold the legs on as well. I first punched holes in the braces, not so close to the corners as to make riveting difficult, and then carefully transferred the hole location to the frame pieces and drilled the holes. Because I wanted the manufactured rivet head on the outside (smoother, prettier, less likely to snag clothes, etc.) I put the pieces together, inserted the rivets from the outside, and peened them shut cold. When I was done, the frame was very sturdy.
To keep the bricks and the firepot from falling out the bottom, I took several scrap pieces of bar and rivetd them into place across the bottom of the frame. For the firepot, I used 3/4" steel bar that I formed to shape in my brake drum forge (you can see one of the bars in the brake drum forge picture above). For the bricks, I used lighter bars, whatever I had handy, mostly 1/8" to 1/4" thick. I ran one bar across the centerline of each brick course, which was enough to hold them up. To keep the bricks steady, I then lined the base with hardware cloth, making a hole and draping it down to the outside of the firepot.
With the table in good shape, I trimmed the legs to length and riveted them to the braces, with three rivets for each leg. I had considered running a brace across the lower part of the legs, but the table was sturdy enough without it.
After the legs were attached, I turned the table right side up, and arranged the bricks and firepot on their supports. The firepot rides low (too low, as it turns out; one day I'll correct that), so I filled the space with fireclay smoothed over and through the hardware cloth. I also filled some small spaces between the bricks with fireclay to keep everything tight.
To harden the fireclay, I built a charcoal fire in the firepot and kept it fed and burning for a few hours. I had planned to build a double-chamber bellows to provide the air blast, but that project is on hold until I have a place I can store it out of the weather. To get this forge working, I moved the squirrel cage fan from my old brake drum forge to this forge, and added a switch panel by it. I built a sliding air gate to replace the old butterfly valve, and it works a little better (it's still very sensitive). I've also added a foot switch (normally open, step to close) to the fan, so I don't have to remember to flip the switch on the panel.
It's a pretty good forge table, and not expensive. It was a big improvement over the brake drum forge that it replaced. A good firepot makes a big difference! I plan to add some side walls at some time, because I have a little trouble with my charcoal falling over the edges. And I plan to raise the firepot so that the edge is close to the table surface. Other than that, I'm happy with it, and can recommend this type of construction to anyone who wants a good forge table.