Some very good news, some good news, slightly bad news.
Good news : the springs have arrived.
They’ve all been checked to be silver plated via a magnet test.
They also look amazing.
Very good news : the springs have very high conductivity, because not only are the springs silver plated, but also because I removed a coil from the large spring.
Overall, I’d say these are excellent springs. Onto the mechanical analysis :
So, guys, there’s a good reason why I wanted to keep the large springs at 5 coils.
Some data.
Nickel plated large spring: 13mm-12mm. 1mm loss. As expected.
Nickel plated small spring: 11mm-8,5mm. 2,5mm loss. As expected.
Silver plated large spring: 12mm-9,2mm. 2,8mm loss.
Silver plated small spring: 10,5mm-8,0mm. 2,5mm loss. As expected.
You see, when I made the calculations for the 1st spring, I accounted for both yield strength and compression ratio (min height it goes down to). Being less conical than the 2nd gen spring, it had no problem with this.
When I made the calculations for the silver plated large spring, what I did not take into account was the conical shape of the springs, which allowed for more overall compression, which means higher tension, which equals higher force applied, and more room for plastic deformation… You can guess that I’m happy with the large spring, but not ecstatic.
All in all though, I’m still very happy with my springs.
For the 3rd gen springs, I’m just going to keep the same 5 coil design for all of the springs, but spruce up for some multi-layer electroplating.