I’ve operated these things from -80 to 200 C which is not an easy feat. Soldering with Sn96 usually broke the springs.
Anyway, made custom “shaft couplers” out of stainless steel with dowel pins. One company made appropriate PTFE PIN connectors, but you have to be a company to order from them. They would gold plate them if we did 200. We had no other choice.
One side was available gold plated. I forget which, the pin or socket. We needed both in the environmental chamber.
I definitely designed really cute probes. The first was a disaster.