here's how Dunhill makes it https://www.youtube.com/watch?v=MYnTrQDhGTk
if you look on pipedia after watching that video you can get the idea for how Comoy makes there's it's pretty neat when you think about it.
ps. I don't make pipes just spend way too much time on the internet
I can't speak for Dunhill, but I saw Jim Knauss at the Memphis Tinderbox replace Saseini (sp?) dots. He had small rods of some kind of plastic (guess, maybe lucite?) sized to fit the holes in the stem. He'd insertthe rod, trim it flush to the stem, and polish smooth. It was the same on 3 dot & 4 dot Saseinis, may be much the same for a Dunnie.
That's easy enough using plastics which come in rod form and can be easily turned down to the proper size
with a lathe but, a Briar or other type of wood I would think would be next to impossible to turn down
small enough.
Is there someone here that can enlighten me? This is a method I'd like to know how to do.