I wanted to design a chair with the lowest possible moments at each joint but stay away from the original straight leg design. By using Force Effect by Autodesk on an Ipad, this is what I came up with:
With a load of 200lb evenly distributed across the seat of the chair, there is less that 8 lb.* in. of torque at each joint.. Since this is only my first design, I decided to build a 1:8 scale model of the chair out of wooden matches and superglue. Here are the following steps to building it.
Step 1: Set Up and Prep
First is the set up for the project. You will want to place wax paper over a hard surface that you don't mind getting cut up by razor blades. (I used an old notebook that I had laying around) Set out your wooden matches and cut 8 of them to 2in. and 2 more of them to 1.75in. using the razor blade and set them aside.
Step 2: Profile Layout
Layout the profile of the legs with 4 of the 2in. legs forming an "M" and the 1.75in. match forming the top. Make 2 sets of these and use a ruler or straight edge to align the bottom of each of the legs. Then, place a small drop of super glue or wood glue at each of the joints. Let these dry and try not to bump them.
Step 3: Building the Seat
To build the seat, lay out 16 matches side to side with the heads alternating. Place a line of glue perpendicular to the matches on the seat and place a supporting match on the glue path you just drew. This will provide support and keep the seat together.
Step 4: Attaching the Legs to the Seat
This is the tricky part. You need to have something hold the legs in place while the glue drys out. I used a bent piece of cardboard with a slit cut in it. Once both legs are dried, the chair is complete and feel free to place your Christmas dog on top of it :)
Hopefully this model will hold up as I move up to larger scale models! Have fun!