And the purpose was?

I found an interesting relic in my shop yesterday. Nicely made, but I have no idea why I made it.

For that matter, I have no idea what it even is. It’s made of 3/4" plywood, with a hole in the exact center. For whatever reason, I’ve sanded it very smooth. Clearly, I used a disc sander on the outer circumference and a spindle sander in the center hole. But the question is why?

The dimensions seem oddly specific to something, as it’s exactly 4-1/8" in diameter, while the hole is 1-9/16". I suppose those dimensions could just be random, as if I needed something “about four inches” and cut the circle freehand on the band saw and that’s just the size it turned out. But 1-9/16" for the center hole? I checked and, yes, I have a Forstner bit that size but I really had to search for it, so I doubt I just grabbed it at random.

The thing of it is, is that I have this vague, nagging memory of making the darned thing sometime in the last six months or so, but no idea why. I’m guessing I needed something exactly that size for a jig, or maybe for photography purposes. I just don’t remember. But it’s turning into a fun mystery. I’ve placed it prominently in my shop where I’ll see it every day. I figure eventually I’ll stumble over its purpose. Then, I suppose it’ll make perfect sense.