Glueing them as Dave mentioned will certainly get the job done, but Here's how I do them. I just glued a couple of nic/silver rings to a a strip of birch, and cut them out on My panto. Works really well. I'm gonna cut a v-groove template from this one some day, but I've had no problems using It as is, and staying against the rings with the stylus so far, so I have just not bothered to cut one from brass or corian yet. The trick is to turn a stylus to the same diameter as the endmill Your using. By doing that they come out the same size as the Nic/Silver rings.
The black ring was cut from dyed venner. The white ones are cut from Ivory, and the centers make good inlays for the tops of JP's.
I don't have the veneer you need in stock, but if you have some, or can get It to Me, and I can be of service, then I'd be glad to cut some out for you. Just Pm if I can be of help.
Greg