[pianotech] Square Grand Rebuild...

[Joseph Garrett]

Jim said: "<Hmmm? Does that mean that you
did NOT change the scale, but are simply tuning the thing to 425cps? That
is NOT the way I would recommend. If another tuner got involved and didn't
know all of the situation...decided to just tune that sucker at 440cps!
 
 
I rescaled.
 
In the rescale,I dropped tensions across the scale, with exception of
the treble section above the single strut @ C6 which was already very
low in the original scale. With the exception of that treble section
the rest of the scale is below the
original tension, just in case some else cranks it up to 440. But
hopefully I'll be tuning it, at least until I croak, if not longer...I'm
interested in this project.

Now, I'm really confused! Did you rescale it to tensions relevant to
425cps? Or, just arbitrarily change the tension scheme? And,..are you going
to tune it to 440cps? If not, then why change the scale. All...most
confusing Jim!
The way that I approach this situation is to establish a pitch standard for
the instrument. This, I base on the age, the country of origin,  the
manufactuerer and the condition of the instrument. Then I set the scaling
pitch perameter to the pitch I've decided was, likely used by the
designer/manufacturer. Plug all thedata into the program and print it out.
Scope out the basic intent, if any, of the designer. Use
tension/inharmonicity/impedence factors to make a decision what, if
anything, I'll do with the scale. Make those changes and smooth things out.
With the Square grand(s), there is a basic imbalance because of the basic
construction. It's part of what the instrument sounds like. Arbitrary
changes for the sake of tension alone, is not a good way to approach this
sort of thing, imo.It's good that you'll be the tech for now. However,
think about how long that sucker has lasted! It likely will last that much
longer, and you ain't going tobe the tech forever! (unfortunately<G>)
 
I also had some cutesy olde-timey decals made up which identify what
note which pins go to, so I don't loose what's left of my sanity tuning
it.(actually the original setup had the tuning pins identified this way)

Wish I had some of them "cutesy olde-time decals", specifically for that
purpose. I usually use transfers. Time consuming and somewhat
frustrating.<G> It's good that you are trying to preserve what sanity you
have left!<G>
 
Interestingly, the treble section was amazingly low in the original
scaling. At C6 bichord unison tension was 175lbs, dropping to 150ish
(unison) @ A7, A7 being a mere 46.5mm speaking length. (Tension from
the start of plain wire to A7 progressively drops). This really low
tension treble was the only part of the belly that hadn't blow up over
the years. It actually is in pretty good condition, so I left it alone
in the rescale. I'm very curious to see how this all sounds.

That is a typical situation in these scales. Not saying it's good, just
typical. With the over-long string situation  and poor termination, that
section is never going to be much.
That's my take on all of that. Good luck.

Joe
 
Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I