Subject

Time to find a buddy who has a machine shop and barter.

What you want is very easy to make if you have access to a small metal
working lathe and a "Bridgeport" (universal) milling machine.

Many years ago I needed exactly what you are looking for to install
tapered thru hulls in boats.

My friend, also a boater, had a machine shop and came to the rescue.

Lew