In the first picture- It looks like some kind of barrel nut... I don't know if that is the right term. Any idea on how to remove it?
In the next two pictures, there are rollers on a flared shaft. Is the only way to change the roller by cutting the shaft? It seems like a dumb question because it looks like it does, but before I cut 20 shafts, I want to make sure.
Dave. Robert is right, you can drive the cold roll pin out using a punch or a nail/bolt to drive it through. I've encountered those %&*(*&^% type rollers before that were in worse shape than yours. Took a 4" grinder to one end and removed them all. Replaced with 2x4 carpet covered bunks.
We have cut a dozen or more rollers with a small cut-off grinder using a 4.5" disk. If you are doing it by hand, I would use a very fine blade so as to not tear the rubber. Use a piece of masking tape wrapped around the roller for your cutting mark.
Hope this helps.