Tension Increase

[John Ross]

Hi John,
I have successfully raised one of these "old Dominions", a semi-tone. It
took it and held, not with just one tuning, though.
I had been afraid of pinblock seperation, so I took the top off, and
inspected it. The pinblock was attached to what looked like a piece of
railroad track, which had bowed, giving the impression of seperation.
I also would like to know what the added tension, would be in a situation
like this.
In the rural situation I am in, I frequently raise the pitch on the old ones
I run into, a semitone, and even a tone or more. Only of course, if the
situation warrents it. i.e. new owner with child taking lessons, or being
played with other instruments. I always check for pinblock seperation first,
and frequently replace the screws, with carriage bolts all the way through,
to the back.
Looking forward to seeing the answer.
Regards,
John M. Ross
Windsor, Nova Scotia, Canada.
----- Original Message -----
From: "John Lillico, RPT" <staytuned@idirect.com>
To: <pianotech@ptg.org>
Sent: Tuesday, January 04, 2000 12:09 PM
Subject: Tension Increase


> If one raises pitch 1/2 tone to A440, how much tension is added to the
frame, either in percentage or pounds?
>
> I successfully carried this out yesterday on a Dominion (circa 1910) which
showed signs of structural weakness with the treble pin block having pulled
slightly forward.
>
> Just wondered how much extra stress I had caused. Tuning is scheduled in
four weeks.
>
> John Lillico, RPT,
> Oakville, ON
>
>
>