How much vacuum should the pump bellows of an ordinary player piano
pull?  On a Simplex I get a reading of 20 inches momentarily at the
reservoir, which goes quickly down to 15 to 10 steady for 10 seconds
(no pumping).  I get 10 inches off the tracker bar constant when
pumping with one foot.  I looked in Art Reblitz's very good player
piano book but didn't see any vacuum measurements for testing the
pump or stack.

I am hoping that the consensus will be 20 inches constant at the
tracker bar to make a player piano play to the satisfaction of the
operator (the person pushing the pedals).

I never worried about vacuum measurements at the pump because all that
matters is that the reservoir collapses after two to three pumps and
holds halfway for 15 seconds or more.  Then, if the player mechanism
plays for 3 to 5 seconds after ceasing pumping, I consider the rebuild
successful.

30 years ago I worked in a player piano shop in San Francisco.  I thought
I heard that 45 to 65 inches could be gotten momentarily on a good player
pump from a hard push or two on the pedals.  Alas I don't have a personal
player piano to test this out so I appreciate input from this most highly
revered Internet list, or feel free to call my 800 number, especially if
you want to share info on your recent Simplex rebuild.  Thanks.

Richard Moody
www.pnotec.com
tel.: 1-800-244-1906