Is A440 too much tension for old pianos? (was Old Bosie)

[Dave Nereson]

----- Original Message ----- 
From: "Cy Shuster" <741662027@charter.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: Tuesday, January 06, 2004 9:08 AM
Subject: Is A440 too much tension for old pianos? (was Old Bosie)


> I'd like to know whether any pianos can't take the tension of A440 ("A435"
> cast into the plate is a good sign, I understand)...
>
> The complications I refer to are those during a pitch raise, where
bringing
> strings up to tension affects the pitch of strings you've already tuned.
> Obviously you have to do two (or more) passes, but what's the best
sequence
> to get to stability fastest?  (I should have looked in the archives
first).
>
> --Cy--
>
    The way I see it, 440 is only 5 beats per second sharper than 435.
That's about 20 cents in the A 49 area of the scale.  At the end of August,
I go into the schools to tune the pianos for the new school year and almost
all of them, including the old uprights in the practice rooms, are at least
25 cents sharp from summer humidity.  They're at more like 445, or even 450.
And they "take it".  I've raised to 440 the pitch of many, many old pianos
that were designed to be at 435 and they do just fine, usually.  I DO
tighten the plate screws first and inspect the case for structural
integrity.  Over 25 years, I think I've only had 2 that did not "take" the
additional strain.   One of them just broke strings left and right and the
other made a loud bang -- but I couldn't figure out what gave way.  The
plate was intact as far as I could tell after inspecting, the soundboard
looked OK, and it stayed in tune at A 440, but something definitely made a
loud noise.
    All the other old pianos I've raised up to 440 have stayed up there OK.
As far as complications during pitch raising, I always tighten the plate
screws first on old pianos.  I don't feel the sequence is all that important
since the first pass is just a rough-in.  If it's coming up a quarter-step
or more, it's going to settle and drift no matter how many passes you do.
    I avoid bringing some pianos up an entire half-step if:  they're older
than 1900 or so, they have rusty strings and/or tuning pins, the soundboard
and bridges have many cracks and splits in them, the structural integrity of
the case/frame doesn't seem solid, the pinblock appears to be separating, or
if ominous creaks and groans happen part-way through the pitch raise or if I
just have a hunch it's never been up to pitch in 40 years (or however long).
    So, yeah, it's a bit more tension than they were designed to take, but
no more than when they go way sharp in the summer.  And most (not all) of
them are built like trucks and can take it.
    --David Nereson, RPT