This dining table was made from an orange road sign with black flagman logo on it.
I got the sign from a junkyard I used to know, north of Phoenix. It was free. I highly recommend "free", in general, as it will keep the cost of this project down, as well as (hopefully) recycle something someone else thought was trash. All the wood I used was free too, cheap plywood cut in strips, old two-by-fours, and other assorted, mangled, painted, varnished, and peeling scraps from around the shop I worked in. The only new materials are fasteners. Most of my work is with "trash", and in the spirit of freegans and readymakers everywhere, I try to spend as little money as possible. In addition to saving me some trouble, saving money is often a simple way to save the environment -- use less crap. The peeling paint and dings in the sign become an integral part of the aesthetic.
I didn't measure anything except to hold the wood up to the sign or wherever I was trying to attach it, so all directions in here are going to exclude dimensions. I assume the sign you find won't be the same exact size, or the use for your table might be different, etc., so consider these instructions more of a schematic to work out your own design on top of.
All photos by my collaborator, Alfonso Elia.
Step 1: Table Acquisition
Go to a junkyard and ask if they have any signs. Most decent-sized ones will have at least a few. Do not get one that is bent, even slightly, because they are usually made from pretty thick aluminum that is too resilient to bang dents out of. You can also find new and used signs on the internet and eBay.
(Please don't steal signs -- )
Step 2: Box the Perimeter
Use some strips of wood to box the perimeter. It helps to work in standard dimensions of material, so most of the wood in the this table was two-by-fours cut into pieces 1-1/2" square, on a table saw. You can get a lot more wood out of your scrap pile if you trim stuff down this way. That also allows an opportunity to cut away warped, rotted, or otherwise damaged bits.
Attach the wood by screwing into it from the top through the table. I just used a screw gun and drywall screws. The black screws match the graphic. No pilot holes required, aluminum is pretty soft.
Then connect the midpoints of the sides with some more strips of two-by-four. I made some little triangular gussets to attach the diagonals to the side pieces. These can be made out of any scrap masonite, plywood, or thin sheet metal cut into a 45-45-90 triangle.
Step 3: Diagonals
Connect the midpoints of the interior square with the corners of the rim. These pieces sit on top of the others. Screw them in from what will be the underside of the table, not through the sign.
Step 4: Legs!
Legs are definitely the trickiest part in terms of getting the height right and getting the thing to sit level on all four feet. There are some later steps that will help with tweaking the level, so don't sweat it if the table is slightly off at first.
The legs are made of strips of 3/4" plywood ripped down on a band saw to about two inches thick at one end and three or so at the other. This gives them a nice taper, for a little elegance in the stance
I wanted the feet to be directly underneath the outside corners, and the table to be thirty inches high.
I jammed the fat end of a leg piece back into the diagonal center bracing, alongside the brace that runs from the outside corners. Then, from the outside corner, I extended my tape measure straight up thirty inches. Fiddle with the leg piece until it intersects the tape. Mark and cut. To find the miter that will make it lie flat on the floor, hold the new leg, trimmed to length, up to the tape in the same way. Using the corner brace as a straightedge, scribe a line across the leg and cut.
Make eight legs to the same dimensions. Use a quarter-inch machine bolt to attach two legs to each corner brace, the legs sandwiching the brace. Tighten it, but leave some play.
Another brace then drops from the outside corner to the midpoint of the leg. Bolt through the same way. put a third bolt through both legs at the bottom of the leg. Tighten this one way down, and it will pinch the legs together, making another taper in the other dimension of the leg.
Step 5: More Braces
You can see the additional bracing coming together in these photos: two pieces, per leg, intersecting at the midpoint of the leg. The other ends go out to the midpoints of the sides of the table. Just shoot screws into them any which way you can, because everything is coming together at funky angles.
Step 6: Finish Up
The first picture shows all the legs braced out. It's strong enough to use at this point.
To add a little more strength and help the thing sit level, I added the wire diagonal tensioners in the first two pictures. I drilled a hole in the projecting end of the four corner braces that connect the corner of the table and the midpoint of the leg. Using tie wire, baling wire, or rope, make a loop that connects the diagonally opposing holes. Stick a little piece of wood in between the two ropes, and twist until tight, just like applying a tourniquet. Tie off the wood to keep it from spinning out when it's at the desired level of tension. These wires prevent the legs from sliding outward, adding some strength, but their main virtue is the fact that tightening and loosening them can twist the table some and make it lay flat. Fiddle with it until all four feet touch the ground evenly.
The beginning photos also show a flower vase. There was already a big hole in the middle of the table, so I screwed a jar lid to the underside of the table and cut a hole in the middle of it. Fill the corresponding jar with water and thread it into the now-captive cap, and drop the flowers in from above.
Cook something up, and eat it, at your new table.