julianf
Member
- Messages
- 7,963
- Location
- devon, uk
put a 3mm bit in your drill press.
clamp a sacrificial piece of steel/Ali/ply (in order of preference) to the drill table.
drill a hole in your sacrificial piece.
take the bit out of the chuck, and press it into the hole you just drilled, so there's just enough left sticking out to register the hole in your panel.
you now have a 3mm guide pin directly centred on the chuck.
put a 4mm end mill/router bit in the chuck.
you can now drop your 3mm hole over the pin, and drill your counter bore.
That's not a bad idea, if I'm following you correctly - register using a pin on the press table, rather than a pin on the cutter.