[CAUT] Upright geometry problem (Nordiska)

[Fred S Sturm]

Interesting observation. It makes me suspicious though 
that there may be something besides or in addition to 
springs causing the problem. Damper wires hitting spring 
rail felt or its equivalent? Jack hitting a rail or other 
something designed to limit its travel? Damper springs 
digging into some trough in the spring groove? Jack 
springs that have so much wire, they can't compress 
enough?

I'm not sure what else there might be, but I'd sure be 
looking for it. Springs may make an action "heavier at the 
bottom of the keystroke" but shouldn't be "that hard," at 
least I wouldn't think so. Of course, I'm not faced with 
those pianos, and haven't run into what you folks are 
describing, so what do I know? I have run into a few 
pianos, usually old uprights, where damper felt seemingly 
twice the thickness of the original was used as 
replacement, and spring strength made it so that playing 
with a light touch you would get hammer bobble, but 
somehow that doesn't seem like what Jim Busby was 
describing. I guess one question to ask is whether playing 
with the pedal down makes a really marked difference.
Regards,
Fred Sturm
University of New Mexico

On Sun, 14 Oct 2007 12:54:17 -0700
  David Brown <dcbrown5 at exchange.asu.edu> wrote:
> Hi Jim-
> 
> We found that the blow had been increased and the dip 
>increased so much in
> an attempt to give aftertouch it wasn¹t getting due to 
>the strong damper,
> hammer and jack springs. You just couldn¹t play hard 
>enough to overcome the
> spring strength and get the jack to clear.
> 
> Just my 2 cents.
> 
> David
> David C. Brown 
> Arizona State University
> School of Music
> Piano Technician
> 1-480-965-6760
> david.c.brown.2 at asu.edu
> 
>