Thanks for the tip, I'm going to try a few things until I find something that works.
Thin wall pipe might be the answer, even better if it works on an arbor press.
I have a hole saw coming that I'll put on the drill press, the leather is glued to a board and the board is held by clamps.
My only concern is some minimal wobble without the drill bit in the center but we'll see what happens.
Another idea is gluing the leather to a round wooden disc and trim it on the router table using a bearing guide on the wood.
Thanks again,
Kevin.