All good stuff Nino, but this is more about the "press fit" between the barrel and the plate that seems to develop resistance..
I always solder the barrel and plate after cleaning them with a wirewheel in a Dremel so the solder will take. Have a look in my "Roller Disco" thread in restorations... i've included a pic there showing this work.
Hope this is of some use to you!!
Cheers.. Mitch
