I’m sure many of you have already seen the “captive nut” in one form or another. I came across it a few years ago and forgot all about it until it showed up on the forum recently.
Here’s Gareth Bell’s Captive Nut:
And here’s another version by Jerry:
It’s a great project for the beginner for a couple of reasons, but mostly because it allows you to practice single-point threading. Once you’re done you’ve got quite the conversation piece that will puzzle and entertain kids and adults alike.
For more information (including links with directions on how to make your own) visit the original forum post by Gareth.