Rescaling question

[Delwin D Fandrich]

Delwin D Fandrich wrote:

> I have.  Several of them.  And most of them were on lesser-known pianos such as
> the Jesse French.  As I said earlier, the problem area is at the bass/tenor
> break.  If this looks adequately strong then there probably won't be any problem.

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Perhaps I should clarify . . . .

Back in the "good old days" -- when the concepts of rescaling were in their infancy
-- a fair amount of what might be best called "free-thinking" was applied to piano
scales.  Often little thought was given to the physical characteristics of the
plate.  If it looked good on paper it must be good for the piano.  The practice of
re-scaling has come a long way since then.  But I still get some concerned when I
hear of anyone taking a scale above the original tension level used by the factory.
Especially someone who has little experience analyzing piano scales and, probably,
the strength potential of piano plates.

Keep in mind that even with this restriction it is still possible to overload certain
plate members.  Consider that many piano scales, especially small ones, really drop
tension through the low tenor.  It is common re-scaling practice to increase this.
Now consider that this same piano might have had fairly low tensions at the upper
bass bi-chords -- also not an uncommon scenario.  So those get raised as well.  We
find that we can keep approximately the same overall tension on the scale because the
mid-tenor tri-chord tensions were quite high.  The problem, of course, is that the
bass/tenor brace now has quite a lot more stress on it than it had originally.  It's
true that the tenor/treble brace is more lightly loaded now, but that doesn't help
the bass/tenor brace at all.  It is entirely possible to increase the load on the
bass/tenor brace by 20% or 30% without increasing the overall scale tension at all.

I am obviously a firm believer in the practice of re-scaling older pianos.  I would
just urge a bit of caution along the way.

Del