I have always used Bob Streicher's replacement Teflon insert when
restoring Ampico A's.  This insert replaces all the leather and ball
bearing with a one-piece insert.  The insert comes with an "O" ring
that is supposed to fit snugly in the end.

The ring can cause the end of the spool to crack and so I leave it off.
Instead I run a little Sobo glue around the "O" ring area to seal the
new insert against the wood.

Paul Manganaro