I'm working on a little project (for the portable workstation contest...) and needed to make a stool. Something small, able to break down easily and store flat. I've come across some of these designs online and decided to create my own.
The concept is a pretty simple one - two slots from opposite ends allow the legs to lock into place. The top pops on and locks it all down. Have a seat!
I made this prototype from cheaper pressboard commonly found in Home Improvement stores very inexpensively. If I were to mass produce these (which I am working towards.... please respect the license) I'd go something more Birch ply or Apple ply.
Design was made with Aspire software to be cut on my CNC machine from a 32" x 48" piece of ply. (32" is as large as I can easily transport in my Jetta, so I buy a full sheet and have them rip into thirds at the store. Plus it's a lot lighter in 3rds and easier to get into my wood lab!)
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I've exported the design files as .DXF file as well as SVG files if you want to bring it into your software to tweak or to print out
Step 1: Let's Design It!
The design is a rather simple one. Two slots (the thickness of the wood), one on the top and one on the bottom, allow the pieces to interlock. That gives it the stability needed to hold one's butt up in the air.
The top piece is actually two pieces, one that the slots go thru, and one that the slots are halfway thru. Easiest way to make these are via a CNC machine... A laser machine would work but you would probably have to do it in layers unless your laser machine can cut thru 3/4" ply. A drill press can also make the holes but a chisel would need to be employed to cut the recesses left behind since the bits are rounded.
There are tags on the images. Explanation:
One piece (top right of picture) is the top (where your butt goes). It's recessed half of the material thickness. The top left is the other top piece, which the slots are all the way thru. My material thickness was 3/4", so the left one was recessed thru and the right one was pocketed out 3/8.
The tabs on the stool were made at 1 1/2" length and 1.125" tall (3/4" + 3/8" = 1.125" or 1 1/8")
The sides of the legs had material removed to reduce weight. It does detract from the total stability of the stool, but I won't be standing on it. Or dancing. Or wiggling. Just sitting.
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The total height is set at 24" and the seat base is a 12" diameter. I made a melamine one (picture is the intro image in white) that I modified to 28". In my CAD software I ended up cutting the nodes at the legs and stretching those and reattaching, so they didn't stretch the tabs at the top.
Eventually I want to sell these, engrave stuff on the sides or wrap them with vinyl...
Step 2: Let's Cut Them!
This part is the easy one if you have a CNC machine or access to one. Some areas have TechShops or local maker communities that have CNC machines to use. Those that don't, you will have to get that scroll / jig / band saw warmed up!
Those with laser cutters, as indicated last step, if you can cut thru 3/4 ply you can probably make these on there. I don't have a laser machine so I'm not sure, but everything I've seen was thinner 1/8" material, so i'd imagine not.
If you are doing it with a scroll saw or jig saw, the inner cuts of the legs wouldn't be too difficult. I don't think you can use a band saw on those inner cut outs...
Step 3: Let's Paint and Assemble!
Now that the pieces are cut out, lets get them painted and assembled!
I cut my initial one out of OSB (pressboard) and used simple flat black latex paint to give it some style. You can leave it plain, or bare wood or stain (if plywood is used, I wouldn't bother staining OSB....)
Assembly: Take the two legs and slide the notches together.
Take the thru-notched piece and pop it on the top. Take the half recessed piece and pop it over that. Make sure everything fits ok, and remove the tops. Now, put some wood glue on the recessed top, and re-assemble them onto the legs. Make sure to NOT get glue near the slots, as it'll interfere with the assembly once dry.
With glue on the top pieces, assemble and clamp the two tops together and then remove. Let dry. (I had to chisel out some of the side and some glue from my slots...
Step 4: Break It Down!
Now that everything is painted and glued, you have a break down stool! Coolest part is that it takes very little room to store, and assembly is a snap!
As you can see in the picture, the broken down stool takes up very little room. Perfect for a portable operation or tight quarters!