Drying pinblock before stringing-slight clarification.

[Ken Jankura]

Thump,
Will you and RicB please read my posts again. Pins in pinblocks get looser
in winter, tighter in summer. We are on the same page here, please already.
I told you (Thump) I didn't think it mattered if you dried the pinblock down
after it was drilled, and what I meant was I do not think that to go from
some average room RH% EMC down to 32% room EMC is enough of a change to
effect the holes enough to matter. In fact, around here, at this time of
year, you'd have to add moisture to the room to get it to 32%. But yes, if
you dry the block down after drilling, you will lessen the fiber tear upon
pin pounding, to some degree. Go for it, that is a good thing. Don't get
hung up on it as if it is a lifesaver for the future of the piano.  I still
think drying the block down before drilling (if you think you must), and
choosing the optimum drill bit size, will have a greater long range effect.
Like Ron N pointed out, you overstep the fiber stress limit when you pound
the pins in no matter what.
Ken Jankura

Previous post excerpts:
_________

To summarize:
Holes in wood act like wood-
High humidity, wood gets bigger, hole gets bigger
Low humidity, wood gets smaller, hole gets smaller
Cross-ply laminated wood does not follow the above rule, and sometimes acts
OPPOSITE, as in:
Pinblocks-
Only the wood cells right around the cut edge of the inside of a tuning pin
hole are able to freely shrink and swell with humidity changes, as the rest
of the wood is constrained by the cross-ply construction. But those
shrinking or swelling cells are enough to make tuning pins-
Looser in winter (dry)
Tighter in summer (humid)
______

Pinblocks are from another planet and do not follow the golden wood rule.
The wood is constrained  from free movement by the cross laminations, so the
only place it can expand or contract is just around the cut edges. Wood
cells shrink just around the tuning pin hole in the dry season, so loose
pins; wood cells swell just around the tuning pin hole in humid season, so
tight pins.
A piece of wood and a piece of pinblock react differently, never ever
confuse the two or you might get something stuck.
Read Bruce Hoadley 'Understanding Wood', don't just take my word for it.

----- Original Message -----
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Monday, March 03, 2003 10:11 PM
Subject: Re: Drying pinblock before stringing-slight clarification.


> Well, and I think that its sensible enough to assume
> that an old block, where the prime exposure to
> atmosphere is the little gap around the pins, and
> where much dimensional change is restricted by the
> glued-uppedness of laminations, will do its expanding
> (with humidity) TOWARDS the hole!
>     But that's the last I'll say on it. I remain
> unconvinced.
>      Thump
>
> --- Richard Brekne <Richard.Brekne@grieg.uib.no>
> wrote:
> >
> >
> > gordon stelter wrote:
> >
> > > I still disagree, Ken. As I have experienced
> > plenty of
> > > pianos develop looser pins in winter, when the
> > > humidity is low
> >
> > Gotta agree here...but will be the first to qualify
> > that I have never
> > reallly checked with an ol torque-o-meter to see for
> > sure. Still.... I
> > could swear that my general experience is that pins
> > get looser in the
> > winter when  the air is dry and cold outside, and
> > the heating on the
> > inside dries things out even more.
> >
> > But I respect Kens whats and nots enough to give him
> > the benifit of the
> > doubt on this one... til I check it for myself.
> >
> > RicB
> >
> > Richard Brekne
> > RPT, N.P.T.F.
> > UiB, Bergen, Norway
> > mailto:rbrekne@broadpark.no
> > http://home.broadpark.no/~rbrekne/ricmain.html
> >
> >
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