[pianotech] Kimball Spinet with HEAVY Sponge Action

[Phil Frankenberg]

The spongeiness you describe could be caused by swollen balance rail button 
bushings.

Phil Frankenberg
CSUChico
Chico Ca.

-----Original Message----- 
From: Terry Farrell
Sent: Wednesday, December 05, 2012 3:03 PM
To: pianotech at ptg.org
Subject: [pianotech] Kimball Spinet with HEAVY Sponge Action

I was stumped this morning (and still am). I went to tune a 1960s (or so) 
Kimball spinet this morning. Sat down at the piano and struck a big cord 
with both hands. YUK!  Totally weird action. Felt like someone dropped a 
four-foot long sponge down into the action. ALL keys move heavy initially, 
and then resistance keeps increasing as you push down. Piano clearly hasn't 
seen a regulation since it left the factory (assuming it was regulated 
then) - but that wouldn't explain the heavy sponge action. It has excess 
lost motion, let off is 1/4", etc., etc., but nothing to explain the spongy 
action. Looked for split rails, any action components way out of whack, but 
didn't see anything unusual.

The only thing I could think of - and I don't know if this is even 
possible - is the crusty/crunchy rubber nuts for the drop stickers (is that 
what they are called?). They are all real hard and I suspect they will 
crunch up right quick if you tried to remove one. I wanted to to isolate 
action & keys, but didn't have any spares with me, so I didn't as I knew 
they would crunch apart.

When the key is depressed and the rubber nut and drop sticker rise, the 
angle that the drop sticker makes with the key changes. If the rubber nut is 
very hard, I guess it would tend to resist that angle change as the key is 
depressed - AND it would tend increase resistance as the key is depressed.

BUT, that angle changes so little - seems hard to believe that it could have 
THAT much effect.

With the lost motion available, I checked action freeness as best I could 
and it seems very free, as do the keys (what I could tell).

Anyone have either an opinion on whether it could actually be hard rubber 
nuts causing the heavy spongy action, or any other ideas???????

Thanks!  Hey, maybe this will at least make a good puzzler!

Terry Farrell=