Has anybody used an end mill to countersink Ligne 24 sockets into thick leather?

[Wizcrafts]

I use very thick leather to make some of my belts (13-16 oz). Normally I supply Chicago Screws to secure the folded over ends to the front. But, some customers prefer Ligne 24 snaps so they can swap buckles without using a tool to hold the Chicago Screw cap. Aside from buying longer post buttons (custom order), or a flat blade skiving tool (bad results), has anybody tried gouging a countersunk hole in the flesh side to drop the back of a Ligne 24 socket below the surface with a 9/16" end mill? If so, what results did you get?

If somebody makes a custom 9/16" end mill with a (~3/32") centering pin (for a #3 hole), please PM me. My drill press has a 5/8" chuck and can accept a 9/16" steel rod.

[electrathon]

Use a forstner drill bit.  Set the stop on your drill press.

A lot easier and faster to order longer posts on the snaps.