Thanks to SimonUK for this link.

Scroll down to the bottom of the page for a video clip of hand-making a triode tube/valve from scratch:

http://paillard.claude.free.fr/

There are some other interesting pages on the site for anyone who can read a little French.

Just checked out the website and video, that was very ineresting. I've always kinda wondered how those were made ever since I found some in the garbage.