Introduction: Convert Wood Chairs to Modular Structures

About: I'm an applied physicist by training(phd Yale 2006, BA Berkeley 1998, math and physics), and have done physics research in the federal government and product development in the private sector, starting two of …

You can often find wood chairs in the trash, at least in anywhere in the USA. This is a method for converting the only slightly broken chair into useful structural elements made from tetrahedra and octahedra which can expand to create a modular system of scaffolds for scalable industrial production in the post capitalist trash-driven world.

Start by gathering what you need:

1 wooden chair
A saw
A marker
A drill and quarter inch bit
Clothes line or nylon parachute cord
Possibly a screwdriver or hammer depending on chair design
Dust pan and broom

Step 1: Mark 6 Segments of Equal Length

Using your arm for a measuring tape, find the shortest of 6 segments that you want to use for your tetrahedron. This can be plus or minus a couple inches here, you'll fix the errors later. Just make sure they're close to 6 equal pieces. If that's impossible due to severe smashing of the chair, just find more chairs and add segments until you get 6. They do NOT all have to come from the same chair or even type of chair.

Step 2: Cut 6 Pieces, Rip Out Metal, Clean Up

This is where the messy part starts, so go find a place that will be easy to clean up with your dust pan and broom and the mess won't annoy anyone. Cut all 6 segments with the saw, then rip chair apart with bare hands and feet as much as possible, then rip metal out with pliers.

Step 3: Cut All Pieces to the Same Length

Now I want to be within better than half an inch of all the same, this is where you fix errors in the initial cut.

Step 4: Drill Holes, One in Each End of Each Piece

About an inch in works well, quarter inch bit, can be driven by electric drill, hand drill, or water or air powered drill. In some cases there will be existing holes from screws or huge nails you can use but it does not hurt to clear those out with the 1/4 inch bit to be sure the size is big enough.

Watch out for staples, nails and screws on your metal bit! It's not the end of the world, but it's not great for the bit.

This concludes the mess-making part, so you can clean up all the wood shavings, and get rid of them now, and can work on the rest of the project in a place where it's not ok to make a mess.

Step 5: Cut Out 4 Cords

These can be from clothesline or nylon cord if you really care about strength at all. If you're using nylon cord don't forget to burn the ends. About 12 inches should work, but you'll be able to fix this later if you want.

Step 6: Tie Joints With Square Knots, Assembling Tetrahedron

A tetrahedron has four faces, four vertices, and 6 edges. You build it up one piece at a time until you have all 4 joints, then adjust and re-tie as needed so it's pretty close to symmetric. Note closeup of square knot. Look up how to tie it on here if unfamiliar, it's a very useful knot.

Step 7: Expand and Document, Scale Up

As I discuss elsewhere, I believe the combination of tetrahedra and octahedra is a great basis for industrial infrastructure of all kinds and scales, from meters to microns. Shown here is connecting the pyramid from 1/2 of an octahedron with the tetrahedron to make the beginning of a structural system that could be extended indefinitely. Cardboard structures of the same kind are shown here as well so show how these systems could all connect in a fractal way. I then make sure all this stuff is documented on some kind of free file sharing site, in my case Pinterest, and affix that URL to the physical artifact so that it can self replicate.