Also for cutting a conical recess for countersink screws, I use some 6 flute carbide cutters:



I've got two sizes.
The small one has a 1/4" flute is particularly adapted to super scale embedding of micro countersunk screws.
I also use it to machine offset hinges securing screw recess, and for scale panel access fasteners.

The other size is 1/2" flute and is very handy for bigger countersunk screws like nylon screws, retract fasteners that need to be flush, or any other heavier duty job.

Both tools are USA designed and made titanium oxide coated carbide cutters.
http://www.ultimate-jets.net/collect...de-countersink

Here is a video showing the use of the 1/4" flute countersink on the Scorpion Mk2 fuselage:

https://vimeo.com/69360377