Drying pinblock before stringing-slight clarification.

[Delwin D Fandrich]

----- Original Message -----
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: March 03, 2003 6:26 AM
Subject: Re: Drying pinblock before stringing-slight clarification.


> I still disagree, Ken. As I have experienced plenty of
> pianos develop looser pins in winter, when the
> humidity is low, I believe that this will "open up"
> the holes a little prior to stringing, preventing some
> fiber tear on pin pounding and then the pin will be a
> little tighter when the EMC rises. As I am not going
> to test this scientifically, and as  I am a neurotic
> compulsive perfectionist with a "better safe than
> sorry"-"do my very best for the customer" complex, I
> will continue this practice until someone shows me
> hard scientific evidence, not just their opinion, that
> it is worthless.
>      Have a Nice Day!
>      Thump

Well, it is a fairly well researched and documented fact that a hole of
given size in a piece of wood expands and contracts along with the expansion
and contraction of the wood. This is Basic Wood Technology 101. Check R.
Bruce Hoadley's 'Understanding Wood' for details.

So, since the change in tuning pin torque you are finding is also real and
well documented, there must be some other mechanism at work here.

Since this subject comes up from time to time there is an accumulated (and
accumulating) amount of information in the archives. One I have brought up
in the past (others as well, I expect) is that the coefficient of friction
between the metal pin and the wood surface changes as the moisture content
of the wood changes. It decreases as the moisture content goes down and
increases as the moisture content goes up. I've no idea if this change is
enough to account for the variation in tuning pin torque felt in some pianos
but, if it were a question I was interested in enough to do some research
answering, this is where I'd start....

Del