I am currently working on a stackable side chair that is built around 2 wooden bands which the seat and legs are fastened to, providing structural support without bulk.

The original idea for this chair did not come from sketching as is often the case in my process. I wanted to exploring the idea of using laser or water jet cut sheet steel or aluminum for bending and cutting out flanges that could be fastened to a light wooden frame. I also wanted to hide most points where hardware is normally visible. It is also important that the chairs be manufacturable in a way that I can afford to prototype.

The first iteration of this design looked like this:

I usually try to get away with using the least amount of material possible. This version had at least 2 problems right away. The first is that a sitter, if they sit in any postion but dead center, would probably bend the sheet metal. To what degree, I am not sure. But I didn’t want to find out. So I would have to change the support piece to cover more area under the sitting surface to prevent severe bowing or bending of the sheet metal. The other issue is that the chair is not stackable. I would need to work out a way that the chair could stack no fewer than 6 chairs high.

So the next iteration looked like this:

The addressed the stacking issue. I figured out that the front part of the legs needed to flare out at a slightly great angle to make room underneath for other legs. I still however have the bending/bowing issue. I really didn’t want to add anything more. So I dragged my feet a bit on changing this.

But once I did, it looked like this:

I also wanted to see how the design might look with Walnut instead of Oak or Maple. Can’t say I was too crazy about it. But the design did not seem to suffer from splitting the support piece in two. I thought maybe all that was left to do was tweak chamfer and fillet details. But as I was lying in bed one night, I began to worry about what might happen to the flanges that are fastened to the supports when the sitter is really heavy or when the chair is picked up. I did not want the legs to move at all under these circumstances. So I decided it was worth investigating the addition of  more flanges to help the other fastened set). Bending two sets would be much more difficult to do and should keep the legs (which at this point are steel tube) from moving at all. I was also thinking that it might make even more interesting negative space on the sitting surfaces.

The latest version looks like this:

I’m not completely set on this current design. I might look at bring additional cut out flanges to the seat back as well so that the seat back and pan have basically the same pattern. One of the great things about the wooden supports is that they make a soft surface for stacking and protecting the powder coated surface of the seat faces.

Here is an additional idea for a stack able accompanying ottoman:

Things to do in the real world: find CNC tube bender as well as sheet metal cutting, bending, punching. Test flexibility of various gauges of aluminum and steel.