The Lester action is very similar in design to a Standard player action,
but is not made with the same kind of uniformity and precision as a
Standard.  Lester requires more valve wobble in order for the valves
to seal properly.  With Lester valve plates I found that the upper seat
and the guides are not aligned as well as in Standard.  I needed a
looser fit of the valve leather on the wire stem in order to get the
wobble I want.

This looser fit can possibly cause the fiber washer and leather facing
to ride up on the wire stem.  When this happens higher air pressure
cannot enter to reopen the pneumatic.  When the pneumatic cannot
reopen as well it's because the valve facing is preventing air from
entering; this will affect repetition.  The collar can prevent the
valve facing from possibly riding up the wire stem.  If the Lester that
you're working on is made with more precision than those I have, you
don't need excessive wobble or the collars.

Just to be safe I pull the collar off with my modified cork screw and
press it back in with my drill press.  By more wobble I don't mean too
much, because this can cause leakage or prevent notes from functioning
properly.  I figure as long as I'm in there, I should just give it the
extra wobble on both facings and put the collar back.

I would also clean off the verdigris and replace or clean and coat the
inside valve facing with lacquer.  The inside facing is patent leather.
Patent leather is coated with lacquer to help prevent dry rot.

Bill Maguire