Tapered throughulls

[albrazzi]

I want to install tapered flush mount throughull fittings they are all standard now. What is the best way to cut the taper in the hull? I understand the need for backing plates for proper hull thickness.

[SailingHarmonie]

They are usually a simple 45 deg chamfer, 1/4” deep. They are most easily cut with a piloted 45 deg router bit after the straight part of the hole is drilled.