I was recently asked by a cyclist if it was possible to build a rolling stool that used a bike saddle as a seat. Much like when working on cars, a low rolling stool is often just the thing when your prized racing steed* is up on the stand for service. Who am I, a four-wheeled object enthusiast, to say this wouldn’t be great? Thus was born the bike stool.
*cyclists never use this word. I am a giant dork.
The vision was very simple- go to the metal recycler and find some tubing with an outside diameter that would match one of those weird clamp things that hold bike seats on to bike seat posts. That same tubing would be used to make three legs at a 45° angle from the center upright. Attach some nice casters, and Bob’s your uncle. Amazingly, it mostly went to plan, and a few nutty techniques that I tried actually worked out. Let’s dive in.
When buying stock, I always buy 50-100% more than I need. This has two advantages. First, it gives you the freedom to make mistakes. Second, everything always take more stock than you think it will. Sometimes the pieces you cut don’t divide nicely into the stock lengths, sometimes you measure wrong, sometimes it’s after noon somewhere and you’re drunk. Whatever the reason, you’ll need more stock than you think. The other advantage is that you then usually have some left over for the next project. Having a variety of materials on hand makes fabrication projects so much easier. I love it when I can do a project without going to the store at all. The more extra bits I have on the junk pile, the more likely that is to happen. Also, the more likely the neighbors are to lodge a complaint about the post-apocalyptic scrap yard that I am clearly running out of my back yard. Nevertheless, buy extra.
Right off the bat, I knew what the primary challenge would be on this project. Imagine a vertical piece of tubing with three other pieces attached at 45º angles. Any time two pieces of round tubing meet, you need what’s often called a “fish mouth” or “saddle” joint. If you remember your high-school conics, you know why it’s called that. Imagine one cylinder intersecting another such that a tight seal is formed. The resulting piece you have taken out of one cylinder looks like the mouth of a fish.
That seems like a very difficult cut to make, but there are lot of interesting ways to do it. First off, there are commercial jigs and machines for the purpose. Tubing Joiners and Fishmouth Jigs of various types exist, and they are very fancy. At the other end of the spectrum, you can simply use an angle grinder to chew away the end of the pipe until you get a good fit. In my case, remember that the stool legs are at a 45º angle to the upright post. That means I need a 45º fishmouth, which adds an extra layer of trickiness. If the angle of the cut isn’t just right, the legs won’t mount properly. An angle-grinder wasn’t going to cut it.
I decided to try rigging up a hole saw on the drill press to do the job. This setup looks really janky, but it actually worked quite well. This puts a lot of lateral stress on the quill of the drill press, so I wouldn’t make a habit of it. In a pinch though, it worked great.
I did a few practice cuts and experimented with different clamping arrangements until I landed on something that worked well. Remember when I told you to buy extra stock? Here’s another reason why. It’s always good to practice a technique that you’re not sure is going to work.
With the cuts figured out, I needed to do some layout. Since this is furniture, getting everything really plumb and square is important. Nothing is more annoying to use than crooked furniture.
To get everything plumb, I decided to use our old frenemy, gravity. I leveled my welding table carefully, then made the center post square and plumb to that surface. I left the center post long so that it can sit on the table and provide a reference for all the other pieces.
With the legs done, it’s time for some feet. We need flat parts at the end of the tubing upon which to mount the caster wheels. One way to do that would be to crimp the end of the tubing flat with a hydraulic or screw press, then bend the resulting tab into a horizontal position. This is probably how a factory would do it. I opted for another route- making some standalone tabs to weld into the ends of the tubing. I felt it would be easier to get an even and level result this way.
The junk pile coughed up some flat stock that was the same width as the diameter of the tubing. Have faith in thy junk pile, and thy junk pile will provide for thee. I needed to make a clean 45º bend so the feet would sit flat when inserted into the tubing.
We now have a straight and square kerf (thanks to the properly set up bandsaw). It’s easy to then use a bench vise or pliers to bend the piece to a clean, sharp 45º bend. Next, I ground down the edges of one side of the bent piece, so that the piece fits inside the tubing.
With all three feet made, it’s time for another test fit.
Once the feet were in exactly the right place, I tacked everything together. Then I welded the feet fully into the tubing. I also tacked the bends on the feet, so I wasn’t relying solely on that kerf bend to hold your weight.
It’s final test-fit time!
If you’ve ever doubted the need for a respirator while spray painting, try an experiment for me. Stand 20 feet back from someone else spray-painting on a bright sunny day. Look at the area from different angles, and you will see that the person doing the painting is standing in a 10′ spherical cloud of paint dust and propellant chemicals. You don’t perceive it much when you are the painter, but you are breathing in a ton of nasty stuff. I never bothered with a respirator when painting until I stumbled into the above experiment, one sunny day at a friend’s house.
So, final assembly, all good, everything is beautiful, time to crack a beer and celebrate. Right? Right? Well, this is Blonidhacks, and something has to go wrong, or it isn’t interesting. I assembled the stool and was doing some high-speed test runs around the smooth floors in my kitchen. At one point, I coasted backwards at high speed and snagged the edge of a floor mat.
The stool keeled over, and when I had picked up the pieces of my dignity, I realized all was not well.
The great thing about steel is that nothing is irreversible and everything is fixable.
A new coat of paint on the feet, and now we’re really done.
Side bar: The casters didn’t come with nuts, so I bought some from the hardware aisle at Home Depot. They are 9/16″ nuts, but I have mostly metric tools, so I grabbed a 14mm wrench (which is basically equivalent). What amazed me is that this hardware is so poorly made that some of them fit a 14mm wrench, and some didn’t. Some were a full millimeter oversized, requiring a 15mm wrench. That’s an amazingly poor level of quality control, and makes me wonder about the metallurgy as well. I would probably hesitate to trust my life to one of these nuts on, for example, suspension parts on a car. I hardly expected Home Depot hardware to be posh, but this was lowest level of quality I’ve seen in hardware to date.
Okay, enough crotchetiness. Back to the final product- how well does it work?
Most importantly, does my new assistant Sprocket H.G. Shopcat (you can call her Sprocket for short) approve of the project?
I’ll take that as a yes.