When to do it

[David Renaud]

When humidity has been high, things swell up and become tighter, lost
motion decreases
When things dry out, they shrink, lost motion increases.

I come from the Ottawa valley, Canada. Here the change can
be dramatic. We can get up to100 degree heat and 100%
humidity come July. We can have 50 below zero in January,
and temp. may not exceed  20 below zero for over a week
at a time. Furnaces work overtime, pianos become dry &
increasingly flat through the tenor area.

I remember one of my earlier regulations, at the end of a
long winter. The lost motion was perfect. I was called
back in the summer and all the hammers were riding compleatly
off the hammer rail. Allot. Parts had absorbed some moisture
and expanded.

So in the middle of summer I do lost motion as tight as
possible, but allowing so the jack will still return properly.
In the driest months of winter here, I allow a little bit of
lost motion to creep in. Not much, and keep it even.
This depends in part on how often I will see the client,
and how much I trust the piano to be stable. Some pianos
seem more stable. I assume due to the quality/density
of the felt & cloth.

Is that so?
Is the reason some instruments fair better then others
due to the density/quality of the felt & cloth.
Perhaps it's just geometry. Perhaps humidity changes in
smaller parts have a more profound accumulative effect?
Anybody?
                                            David Renaud
                                            RPT
                                            Canada

Clyde Hollinger wrote:

> Friends,
> What happens to lost motion, particularly in spinets and consoles, when
> the humidity changes?  When does it increase or decrease, and why?
> Regards,
> Clyde