David Schlitter recently posted a few videos from their road trip. In one, they talked to Jeff in Texas about his amazing tool cart. I know there is a followup to explore some of those tips and techniques, but one in particular stood out: the Threaded Insert (with lip) Hinge hack.
For those who don’t want to track down the video, this was an insightful tip to use threaded inserts on opposing ends of conduit with a rod connecting them. Using inserts with the lip gives nice mating surfaces for internally joining conduit end-to-end. This much has been covered before, and it should be noted that it is not a high performance structural joint, but the alignment is fantastic and it looks super clean. Now, what Jeff realized is that if you back the pipes off just a bit from each other, you basically have the makings of a hinge between them with VERY smooth rotation. Jeff’s cart has another joint like this a couple feet opposite and this works as a fold-down table frame. Brilliant!
The only drawback is that you cannot continuously turn the hinge joint—it will either expand apart or seize together—one thread width per revolution.
Assuming David Schlitter and Jake Lewis are going to explore this more, I thought I would throw in an idea/observation:
If you used a lag bold as your threaded rod with this technique, you could tighten it down into one end with the smooth rod (no threads) exposed. Cut off the end of the bolt and you have a protruding smooth rod. Then, on the mating section of conduit, you simply drill out the threads of the lipped insert. Voila, you have a centered “pin” that can slip inside an “unthreaded” insert, and the makings of a perfectly centered, perfectly smooth, continuous hinge.
Attached is an image example of what I mean, cut at the red line.