No real news here.
I did have an adjusting screw seize up in a SunTour Superbe Pro front derailleur and had a rough time getting it out. It ended up with a bit of mangling of the phillips head on the screw before getting serious about the penetrating oil and (eventually) some heat to break the aluminum body free of the steel screw.
In fairness, I've been using the derailleur for 34 years, and doubt that I've ever lubed the screw, so it's my fault.
This was a good opportunity to learn that the limit screws are M4 with a 0.5mm thread. Not exactly something that you find at the hardware store.
I did try to raid one from an older Cyclone that I'd stripped some threads out of, only to find that someone had replaced the equivalent limit screw with a coarser threaded M4!
As an interim fix, I just threw on a different Cyclone while waiting for the penetrating oil to work its magic.
For reference, here's the original limit screw....
This seemed like a good time to tear things apart and clean them up.
While doing so, I noticed that pivot points on the parallelogram had brass inserts! Very nice!
The limit screws now have plenty of anti-seize goo on them, and should be good for another 30 years of abuse (unlike my knees, I'm sure).
Steve in Peoria