[KurtB]

Thanks Rob. I thought hard about using a lathe, because boring in a lathe is 10X easier than a mill. In the end, at least for these prototypes, I decided to use the mill to see how tough it would be. I'm going to look in the MSC catalogue for some 1" square or maybe 0.875" square 5C collets. If those are available, I'll be good to go. For production work, though, the thought of using a 4-jaw, considering how lengthy the setup would be, gives me some pause.

Even better, I'll stop being lazy and program a solid model of the darned thing, at least the coin recess. I've got a bench CNC mill that would make short work of that pocket, and produce a nice finish in the bottom of the cavity to boot. I just need to be sure it can be made with the necessary accuracy.