On Sunday, April 29, 2018 at 1:23:12 PM UTC-4, Electric Comet wrote:
On Thu, 26 Apr 2018 03:26:23 -0700 (PDT)
DerbyDad03 wrote:

Does that sound like a workable plan? Have I chosen the right router
bits for the task?

sounds like overthink

but if the plywood can only be used for this purpose and no other
than buy another piece that is the same thickness as the collar
and place that over the original with a hole big enough to
accommodate the collar

Which basically what I suggested, except that my method ensures that the
larger hole is exactly centered over the smaller hole. If you are suggesting
cutting the larger hole *before* laminating the 2 pieces together, then
you are suggesting doubling the layout work and *hoping* that you get the
layout exactly right. I see no reason to even consider that method as a viable solution.

Perhaps I misunderstood. If so feel free to clarify.