So I've cut a 1/4 circle template out of osb leftover and checked my lumber supply (1m outer diameter and 90cm inner - is it enough? Should I have the ring wider? It's 10cm now, so about 4"). I have some nice 35mm thick short planks that are wide enough to provide four of the circle quarters. Have several more, but those are narrower and would only make 1/8s of the circle, but have enough material to make them half-to-half overlap each other at the joints, while the big 1/4s will be just touching, not overlaping. If I put together the 1/4s and overlay them with a layer of 1/8s, it will likely be sturdy enough, but also too thick and heavy and that's just one "stock" of the slotted ring!
I could find some thinner planks, but the thick ones would be really nice and I was saving them for this purpose for a while. Or should I make this thick ring and just drill holes into the edge, instead of slotting it? I'm a little worried about keeping the exact angle for the holes though, also worried about splitting the wood possibly and last, about joining the layers of the ring - even if I glue them together, I'd still like to put some wood screws through it. Not sure if the holes and screws could always avoid each other (if the screws are supposed to actualy connect the parts well).
Another way would be to make the 1/4s and connect them with a layer of plywood. But as soon as I buy plywood in such measure, I can just get thicker grade plywood and make the rings straight of it, as the Kama Yaminary plans say.
So, how about this? I don't want to give up using lumber rather than plywood, especially as I already have it for free (while having no plywood in that size), but also don't want to make my work tougher than it needs to be.