action centers - correct friction?

[John Formsma]

List,

I am reconditioning (prior to regulation) the action of a 1976 Yamaha G3
grand. The questions I have concern the whippen and balancier action centers
vis-a-vis Don Mannino's post below that I found in searching the archives.

In the section of bass whippens I've disassembled so far, I've noticed most
of the whippen flanges are anywhere from 2-3 grams, measured at the screw
hole. The balancier measures about 1-2 grams, measured at the drop screw
pad.

Regarding what Don wrote below, and I consider him expert in this, I should
repin the loose flanges. However, I wanted to ask the list before I jump
into this. Is there any reason not to repin these centers that I am just
unaware of? Does Yamaha perhaps have a different standard for their
balancier and whippen flange centers? There is also slight sideward play in
the whippen centers, so my initial thinking is they could use repinning.

What say you?


Thanks in advance,

-- 
JF

Written by Don Mannino, 8/11/2007 archived at
https://www.moypiano.com/ptg/pianotech.php/2007-August/209291.html

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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