A while ago, I decided that I wanted to start doing some more serious metal-working and start in the art of manliness: blacksmithing. My only trouble was that I couldnt find many easy ways of building one, so I began planning and building for myself! Hope this helps anyone with the same predicament.
Step 1: Your Materials
58 cement or fire bricks, preferably with the dimensions along the lines of 12"x5"x5"
Steel grating that will be as wide and long as your forge
Air supply/bellows (I used a shop-vac in this case)
Step 2: Laying Your Bricks
Next, you will want to flatten the ground you wish to use for your forge. You could even get some extra bricks and use them as a foundation.
Finally, based on your plan, start laying your bricks down. For my particular forge, I wanted it to be a pretty decent size, so I laid them so that there were 2 full brick lengths on each side.
Step 3: Incorporating Your Bellows
Once you have reached the 5th layer of bricks, slide a brick over far enough to fit the nozzle of your vacuum in. You may cut the protruding part of the brick off for aesthetics, however I did not.
Step 4: Adding Your Grate
The steel grating is there so that as your coal burns down and gets smaller, the ash and useless remnants fall thru and are out of the way. The grating can be moved at a later time to clear the ash out.
Step 5: Finishing Up
Get yourself some hammers, tongs, punches and chisels, an anvil and get to work.
Thanks for reading!