Hi,
In an automated current testing fixture, the following spring loaded testing probe/pin is used:

The material is steel but it's gold plated. The spring force is at most 1.5N but I don't think we are compressing it that much. Anyway, we are getting too much unreliable connections which leads to excessive test failures.
A couple of issues I suspect:
1. The internal spring mechanism doesn't lead to a reliable connection
2. The gold plating wears off and the exposed steel oxidizes on the testing surface
I want to try to modify it by taking away its internal spring loaded mechanism and directly solder a coil spring of my own. Also, by using a stronger spring, it can help to create a stronger connection, which can help with the oxidization issue.
I wonder if it's a good approach to this, and if so, what kind of spring (material) I should get to allow it to be soldered.
Thanks