[ Ref. "Wood Valve Buttons in Standard Double Valve Action"

My experience has been the valve at rest should be even with the pouch
well and not above it.  The pouch will dish on its own over a short
time.

I have a player in the shop that plays a test roll great but when a
song roll is played it sounds horrible.  Watching the roll closely as
it plays shows that extra notes are being played besides the intended
notes.  This is happening because there is leakage between the valve
wells or the channels between the notes that go to the valve well.

The lesson is that you must seal the valve well and the channel leading
to the valve well with shellac.

Don Teach - Shreveport Music Co.
Shreveport, Louisiana