Several readers have asked about the hardware-store solution to the three-way bolt needed for the three-legged folding stool. While I am working on an old-school solution, here is how to accomplish the job with about $3.50 of easy-to-source metal.
Note that this is for 1”-diameter legs. If you bump up to 1-1/8” or 1-1/4”, you will need a longer hex bolt and eye bolt.
One 5/16” x 2-1/2” hex bolt
One 1/4” x 2” eyebolt (if your store carries 5/16”, use that instead)
One 5/16” acorn nut
One 1/4” acorn nut
Two 5/16” washers
One 1/4” washer
When I use this hardware arrangement, I drill 21/64” through-holes in the legs. And I usually coat most of the threads of the eyebolt with some epoxy. This coating prevents the threads from chewing up the hole in the leg.
I’ve had this arrangement in a stool that my 13-year-old daughter has been using daily since last year. So far, so good.
— Christopher Schwarz