Live tooling (router) on slower lathe speed or regular tooling on high lathe speed will do the job. The keys are to make sure the tooling is real sharp and it also matters what the brass rings are sandwiched in between. I would not suggest using wood on either side of the brass, but sandwich it in between phenolic rings. The phenolic gives a hard edge for it to peel off clean up against it. Whereas with wood on either side it can mash the brass over into the softer wood creating a jagged edge that is very hard to get rid of.