The Skeletal Chair at my desk is my favourite seat in the house.
I designed and built this chair three years ago and it has been in regular use ever since. It is comfortable and ergonomic, allowing me to lean side to side or forward, or pivot and turn on the front leg. It is lightweight and can be easily carried with just a single hand. I do most of my writing in this seat, as well as manage paperwork, socialize, and eat the occasional meal.
I like the aesthetics of the design, but have concerns about the strength. I’ve had to repair it four times so far, and that has highlighted the areas that need to be built stronger so that it lasts.
A well-made product should be durable, but the question is, how durable? Is it good enough for an item to endure regular use, or should it also tolerate occasional, or regular abuse such as standing on chairs, lifting furniture by their tops, or being toppled? If a chair intended for adult use cannot support an adult of any size, is that okay? Where is the line between the responsibility of the maker and the user?
If durability was the only concern, we would all be sitting on blocks of concrete. Obviously there are other important factors that lead to a successful design, and each must be carefully weighed in importance, and a good compromise established.
See the evolution of this design, starting with Prototype #1, Prototype #2, Prototype #3, and Prototype #4.
Sculptural Woodwork by Chris Wong 
What if you made the seat from a single piece and back also. 2×12″ fir or something with triangular formed gusset underneath but still one piece. Do you think that would aid in strength?
Danny,
I’m not exactly sure what you’re describing, but it sounds similar to the first prototype. I’m sure that it would increase the strength, but also add bulk and weight – this design seems to be going the other way.
Thanks for the comment.
Chris
That is mighty impressive.
I think you should put each seat and back “rib” on a spring-loaded swivel, designed to flex with the user. That would reduce the pressure on the base and provide another level of coolness to the chair!
Grant,
Very interesting idea. You’ve got me thinking about a human spine, and how something similar could be created. Maybe the ribs could be bolted together with rubber spacers in between to allow some flexibility? For some reason, more complicated mechanisms with springs make me think of building with metal, plastic and other materials not wood.
Chris
Chris, a mechanism that operates very similar to a spine are skateboard trucks. instead of the wheels, perhaps the ribs could be bolted to the trucks?
I remember when you were developing it. good to see it again….and that it is still working for ya.
steve
Chris, what areas failed? Looking at the skeletal structure I was attempting to visualize possible points of failure and thinking through what could be done and still maintain the skeletal form. It’s an interesting exercise. I really like the form. I have not made many chairs, but am wondering if a Maloof type joint broadened out at each intersection on both pieces and then dovetailed as a half lap would create a buttress increasing strength yet still allow a fairly quick transition to “lightness” at the extent of the pieces would solve some strength issues yet maintain the look and feel of the piece.
I am thinking out loud here, really as an attempt to learn, not as an experienced maker. Any discussion on those points would be educational for me.
I look forward to see what you come up with.
As to the larger point and question, I am curious how you as a designer and craftsman approach this. I can see building to the “average person”, when designing and building on spec. Then making changes on bespoke commission pieces, but short of the granite seat I don’t see any way to design to any extreme without losing aesthetics.
Brent,
What failed in all four instances was the area where the ribs met the frame. I had used a cross lap joint and glue. It seems that torque on one end of a rib caused the joint to fail, and I believe that by increasing the thickness of the rib where it meets the frame would be a good step to increase the strength of the joint. A Maloof-style joint would be worth trying.
You present good questions and good ideas.
Chris