Because I am a cheap bastard that wants to use the endcaps of my vacuum chamber as Anode and Katode, Instead of messing around with spark plugs or similar, I need an electrical insulator for my vacuum pump, because the KF16 vacuum line is all metal. Otherwise the pump would sit at 500V potential!
Buying a ceramic insulator is out of the question, and a glass insulator is expensive (could easily reach 100€, SUPPOSING that the selling company wants to do business with an individual). So, I bought borosilicate tube and set my lathe to slow cooking.
Hmmm, looks like the part, doesn’t it?
It fits:
It closes:
Aaaaand…it breaks. (WAS expected, it doesn’t have the proper 15º slope, for starters)
This was done with absolutely ZERO effort, just heating the glass and poking it with a graphite rod.
The Electronic Mercenary 