Make Your own Tri-bolt for a Folding Stool


Woodworker Mike Siemsen devised a clever way to make a three-way bolt for a folding stool using some off-the-rack hardware. He’s making 100 of these hardware sets for Lost Art Press, which we will sell for $12/each plus domestic first-class shipping, as soon as they are available.

When we sell out, Mike will sell them himself.

He sent me a sample hardware set and I installed it on a stool. The hardware works great. It is much less sloppy than the eye-bolt solution outlined in earlier posts. If you have a drill press, some lettered drill bits and a metal tap, you can easily make this hardware yourself using the instructions from Mike below. Note that this hardware is designed for legs that are 1-3/16” in diameter – a good diameter for modern Americans.

If you don’t have the tools or time, we’ll sell the hardware to you. Details to come. Below is how to make your own.

— Christopher Schwarz


Here is a shot of the tri-bolt set up. The parts required are:

• A 1/2-13 heavy hex nut. (Regular nuts will not work well; get low carbon, not hardened)
• Three 5/16-18 x 2-1/4” bolts (machine screws, get low carbon, not hardened)
• One 5/16-18 nut (for cutting off the bolts to length)
• Three 5/16″ washers.

You will also need a 5/16-18 tap, a drill for the pilot hole (F-size bit which is .257”; 1/4″ will probably work) and a drill press.

Center punch the center of every other face on the 1/2″ heavy hex nut, put it in a drill press vise and bore the pilot holes for the tap. You can then either run the tap by hand or put the tap in the drill press and turn it by hand, no power! Keep things square to the face being drilled.

Next take the three 5/16 bolts, screw the nut on them all the way up to the unthreaded portion and saw off the excess end. Remove the nut and file or grind the burr off. It is important that the unthreaded portion be around 1-1/4″ long. You can buy shorter or longer bolts to vary the length of the unthreaded portion. I typically blacken shiny hardware.

— Mike Siemsen

About Lost Art Press

Publisher of woodworking books and videos specializing in hand tool techniques.
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16 Responses to Make Your own Tri-bolt for a Folding Stool

  1. mrfredl says:

    Will all in ten

    Connected by DROID on Verizon Wireless

  2. Nice… But I think I like the “original” method better, look more elegant.

  3. jonathanszczepanski says:

    Woohoo! Woodworker’s never cease to amaze me. “Here are these things that we are going to make and sell, but if you want, here are is how you can make them yourself.” Just wonderful.

    • JMAW Works says:

      I thought the same thing. Great business model, give all the secrets away! WWorking is a community easy to be proud of for things like this.

      I do like the way the fix uses the natural 120° separations of the common hex nut to provide a nice bearing surface. Like many great designs it looks so obvious once you’ve seen it.

  4. Dan Brassaw says:

    That’s an ingenious solution! I don’t particularly like the look of the nut in the middle, but it certainly works if you don’t have a better method. Cheers!

    • lostartpress says:


      The only time you really see the nut is when your head is underneath the seat and between the legs. In other words, almost never. What I personally prefer about the nut solution is that the stool functions more elegantly. The legs don’t flop around as much during the folding and unfolding.

      But both solutions work well and are inexpensive.

  5. An excellent, clever, and very sturdy solution Mike & Chris. Well done!

  6. For those of you who object to the appearance of the nut, could a pair of Chicago screws of the proper diameter and length be fitted through the hole in the nut to camouflage it?

  7. Mike Siemsen says:

    Yes Charles, The Chicago screws would probably work to disguise the nut, but as Chris says you don’t see it. A rivit and a washer would do as well, or just screw in a piece of dowel.
    Simon, I thought about hex bar but for a person making one it would add in the problem of finding hex bar. I also used a nut because it has a hole in the middle which makes it much easier to drill and tap and they are inexpensive.
    Jonathan, yes we like to share, It would be pretty easy to reverse engineer the process anyway.

  8. Nick Webb says:

    Looks awfully like the SketchUp model I sent you back in March 2013 Chris. 😉

  9. wallen2014 says:

    Wow, that’s an awesome geometrical solution to the problem. I have to wonder, though, if in the history of the campaign stool, did the original plan use nuts and bolts made of hickory or ash instead of steel. Do they make a tap and wooden threadbox that small nowadays?

  10. Farmer Greg says:

    “Note that this hardware is designed for legs that are 1-3/16” in diameter – a good diameter for modern Americans.”

    Hey! Did you just call me fat?

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