The Swelling Pin hole Conundrum

[Delwin D Fandrich]

A440A@aol.com wrote:

>  Tom wrote:
> >In a message dated 11/19/97 8:41:13 AM, you wrote:
> >
> ><<"which. after great
> >discussion,  Jon proved to almost everyones satisfaction, that these holes
> do
> >not  behave as one might expect and shrink with the introduction of moisure
> >but actually expand- the hole enlarging!">>
>
>        Hmmmmm,  best I can remember, every single balance rail hole I have
> ever treated with water or glue size was significantly smaller when it had
> dried out. EVERY ONE!
>        Obviously, I am inhabiting a differnt world than those that find the
> holes get larger, (is there is an unknown correlation that causes the balance
> rail pins to expand when their keys get dampened??)
> Regards,
> Ed Foote

---------------------------------------

Ed,

It's a different situation.

In one case the center of the hole is the center of the universe. When the wood fibers making up the key -- or whatever piece
of wood you may happen to have with a hole in it -- are exposed to changes in relative humidity, all of the wood fibers
throughout its section are affected more or less uniformly. That is they all swell or they all shrink. If they all swell,
they all expand away from the center of their universe and the hole gets bigger. If they all shrink, they all shrink toward
the center and the hole gets smaller.

When you glue-size you are only dampening those wood fibers that are immediately adjacent to the hole with the glue-size
mixture. But they are surrounded by unaffected fibers that prevent them from expanding away from the center of the hole. So,
taking the path of least resistance, the head toward the center of the hole. As the water evaporates, the glue dries and
holds them there. The hole is now smaller. And less resilient; hence the clicks and rattles that show up afterwards.

-- ddf