Which inserts wore out?
I make my own from PVC pipe. Is it 3/4" pipe? I use the stuff with a 9/16" interior diameter hole, which I bore out in the drill press with a 5/8" twist drill.
That pipe has a 7/8" outside diameter, so I bore a 7/8" hole in what ever block i want to use to encase the sleeve. Rough up the outside of pipe with 100 grit paper.
Wipe furniture wax into the inside hole. Glue it in place. They last for years. When they wear out you just replace them.