action center question

[Don Mannino]

Brittney,
 
Here are my usual guidelines, with notes.  Gram measurement is made with a
spring gauge at the screw hole, except where noted.


hammer flange centers 

Depends on felt quality and firmness. My usual range would be 2 - 6 grams,
depending on humidity and bushing quality. 2g during dry conditions is OK
with good bushings, but will give poor tone with spongy bushings.  If it's
raining and the bushings are not especially firm feeling, pinning at 6 grams
might be good.  Evenness from note to note is most important in this center.

whippen flange centers 

4 - 6 grams 

balancier center 

4 - 5 grams measured at the drop screw pad (with spring detached, of
course).   This is a very tight feeling bushing when you are testing with
the center pin.
 
Jack should be pinned so that it falls slowly of it's own weight when the
wippen is held with the jack tender pointing up.  This give a correct amount
of friction to match the weight of the upper part of the jack, which helps
control unwanted jack bounces during fast play.
 
Don Mannino
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