I now it takes all the fun out of it but you can buy these from a
trophy/awards supply outfit like Freeman. They come in brass and
aluminum with protective paper. They are perfect circles and the edges
are smooth. Lots of sizes and finishes. Natural, shiny, blue, red,
green, white, black. I have printed thousands of these over the years.
Google for trophy supplies.
If you want to make them I would suggest a router or you could buy this
nice rotary tale I have here and bolt it to your milling machine. Good
luck
Dan