This is the "The Adams Family" Protector for the chair hole

Here is the problem.  No protection and the hole gets worn.
This is the bottom mech.  Take off  screws and expose the area in question.
Here is the protector in place.
Here is the protector installed Should there be a problem with height you may have to file down the front a little.  I tried to make them universal.   Some have more wear then others.