Summary

This is a jig you can bolt to a wood router so you can cut big (19") circles around a point . Use it to cut stool-tops, bending forms, whatever. You can anchor the jig with a pinch-bolt you drill into your workpiece and snug onto the jig through the "ruler" groove. I'd like to make a bearing I could use to make spinning around the anchor bolt a little less futzy...
I laser cut one of these out of 5mm tri-ply "wood" and dunked it in linseed oil. Its delicate but it works.

Instructions

Here's my laser cut schedule for a "cheapo" Chinese laser cutter

speed power mode color desc
400 10 cut black text
400 10 cut pink ruler-ticks
400 10 cut green router
10 100 cut blue edge
You could also just print this out to paper and tape that to some thin wood and cut it out with a router or dremel. As long as you get the measuring ruler groove straight, it should be fairly accurate.
The diameter of the big hole should be sized to line up with the outside edge of your router's mounting ring. I merely score a line on there to use it as a guide for attaching the router. The little hole is the aperture for the tool and is knocked out of the final jig. The circles in the pdf are lined up for my 1/4" 80s Craftsman router.
I hand-drilled three little holes in the big circle to match the bolt pattern on the router's mounting ring. Depending on the thickness of the material you are using for the jig and the lengtg of your router's collets/bits, you may need to etch out the big ring a bit so that your router bit will be able to get decent cut depth when using the jig.
I suppose you could also epoxy a Dremel 566 Tile Cutting Kit to a much smaller hole so you could then use a dremel with this instead of a big ol' router. That would cool for etching or cutting really thin workpieces.

Joey's Router Compass