I am surprised that most builders of vacuum tube equipment don’t know about production tube sockets. Production sockets are designed for a very large number of insertions and extractions. The contacts are extremely rugged and can be replaced individually. The terminals are threaded brass studs. Ideal uses for production sockets are in tube testers, pre-heaters and burn-in fixtures. At Leeds we have a pod fitted with banana jacks that accepts production sockets, of all types from acorn all the way to compactron, for use with Hickok 118A/B tube testers. It saves an enormous amount of time when testing large numbers of the same tube, because the insertion and extraction are smooth and medium to low force. You can test a quantity of tubes in an afternoon that would ruin the regular sockets on a tube tester.