lost motion/ low humidity/plastic action

[Newton Hunt]

You are only partly correct.  Include all the key felts shrinking as
well.  The cumulative effect is lost motion.  Choices have to be made,
quiet operation or stability, Kawai chose quiet operation.

The problem is more complex than this but these are the highlights.

		Newton

Tvak@AOL.COM wrote:
> 
> I had always thought that lost motion that can develop in a low-humidity
> environment (i.e. the winter months here in Chicago) was due to the wood
> action parts drying out and shrinking.  I guess that's an incorrect
> assumption.  I just came across a Kawai vertical that had quite alot of lost
> motion, but all the action parts were plastic, except the key itself.
> Plastic wippen, plastic jack, and plastic hammer butt.  I didn't think
> plastic is affected by humidity.  My guess is that the felt and leather (on
> the wippen and hammer butt) must have shrunk due to low humidity creating the
> lost motion.
> 
> Or is there some other reason that pianos develop lost motion in low
> humidity?  This piano has not been played much since I saw it last year, so I
> don't think it's due to wear.
> 
> Tom Sivak