A new arm presented a rather unexpected problem. I've made its back too heavy, and the arm wouldn't balance! None of the counterweights from various donor arms fit. You can see the temporary solution in the photo. Stopper rings balanced the arm, but I am quite positive this is an awful configuration when it comes to vibration.
As usual, we are comparing our arm to a similar Prototype 5
with regular bearings. We've also kept the vibrometry results from Prototype 5 with steel counterweight stub
as our flexure bearing prototype uses steel stub too.