Rescaling question

[Delwin D Fandrich]

PNOTNR@aol.com wrote:

> . . . .  I bought Tremaine Parson's PSCALE program, and put all the information
> in and
> came up with a pretty nice _looking_ scale.  (This is my first venture into
> rescaling)  My concern at the moment is that the program calculated the
> original scale tension at 38,643 lbs. and the scale I worked out was
> calculated at 40,332 lbs.  My two questions, (no doubt I'll think of more)
> are:
>
> 1.) Is this acceptable?

In my opinion, probably not.  I make it a general rule to not exceed the original
overall scale tension unless I am thoroughly familiar with the plate.  I've been
rescaling pianos for close to 30 years and have not yet broken an original plate.
I don't intend to start now.  The area of most concern will be the plate brace
arrangement between the bass and tenor sections.


> 2.) How do you figure what a plate and frame can take?

You don't.  Unless you're a structural engineer and want to take the time to work
out the stresses involved.  Over time you do develop a sense for what works and
what doesn't work.  But if this is your first attempt at scaling a piano I'd
recommend going back and trying it again until you come up with something closer
to 38,643 pounds.  Give or take a couple of hundred pounds.

Regards,

Del