OK, so I haven't made anything sizeable out of my sycamore yet. I guess I'm a "small items" kinda guy....
I got the idea for the first item from someone's web page. I had been making some refrigerator magnets, and it took some time to fit the magnets "just so" into the bottoms of the pieces. As with the Volcano Shaker, the worst was when I got the magnet (or other insert) to fit just right ... and then I couldn't grab it to pull it back out and apply a dab of glue. (OK, maybe I could/should have left them a little loose.)
Anyway, I call this a "Go/No-Go Magnet Gauge".
The dumb thing was that after I made it, I realized that I only had one magnet left from the old package I'd been using ... and then I couldn't find any more in the stores! (The magnet in the photo is a poor-quality substitute, which isn't even cylindrical. )
The idea is to make the "stub" on the end of the gauge the same diameter as the magnet, and the same depth that you want to insert the magnet. You can feel when you get the diameter right, and you can see when you get the depth right. And it's much easier to pull the gauge out of a tight hole than the magnet.
A week or two back, my wife requested the item below. Her pin cushion kept scooting around on her sewing table, and it was driving her nuts. The design came from her verbal description. The white stuff inserted in the bottom is some shelf liner, which was left protruding just enough to provide some traction. Both the pin cushion and the shelf liner were glued to the base.