[BB_TX]

Obviously you have a better idea since you can actually see them, but I agree with Bob, normally those are knurled on the ends and pressed in. If so, you could try using a hammer and chisel and lightly tapping the chisel multiple times in the knurled area to enlarge it and roughen it up some more. Maybe just a tiny spot of something like gorilla glue on the end. Not too much or it could interfere with the hinge working.

I never have liked those kind of hinges as the bottom pin is prone to falling out over time.