[CAUT] CAF

[David Love]

Similarly, using longer knuckle hangings with light hammers can also create
problems by forcing a weak setting of the repetition spring.  This is
evidenced when opting for 18 mm knuckles positions (which are available) on
some MHs to offset the poor geometry.  

David Love
www.davidlovepianos.com

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Ron
Nossaman
Sent: Monday, August 17, 2009 2:40 PM
To: caut at ptg.org
Subject: Re: [CAUT] CAF

Chris Solliday wrote:

> Lately since "firm but free" (or is it "as free as possible without 
> making noise?") has taken over action center design this problem has 
> come back. I repeat that it is not this simplistic and that other issues 
> of friction and geometry must be examined and corrected as well. 
> However, I believe that we can fix (in the absence of the balancier 
> bridle)  most of the blame on "firm but free."  

I agree. Since we're using entirely the wrong indicator 
(hammer rise instead of key rise) to set rep spring strength, 
free action centers force us to set the spring too weak to 
avoid throwing the hammer up into the string. The near zero 
let off, drop, and after touch trend doesn't help this either. 
If we set the spring from key rise, which is it's function in 
play, and pinned action centers to control resulting hammer 
rise, we'd be in the center of functionality range. Then with 
the balancier height set correctly in relation to the jack, 
let off, checking, and all the other relative non-mysteries 
accounted for, and the shank close to the cushion to do it's 
job, CAF wouldn't come up.

How is it we seem to be getting back to having to rebuild 
every part in every action to get the things to work? Maybe we 
should shoot at the other foot for a while.
Ron N