[Delwin D Fandrich]

David Sanderson wrote:

> In our scale design, over the last ten or so years, we have never seen
> C-88 *designed* at more than 52 mm.

Over the past thirty or so years of scaling and rescaling pianos, I have.
Although I agree that you would probably not see this is rescaling work on older
pianos. Probably through the fifties or so, 48 mm to 50 mm would have been the
standard. Of late, though, the speaking length of C-88 has been creeping up. In
certain modern pianos 54 mm to 56 mm is not all that unusual. (And, no, I can't
lead you to specific instruments right now without a lot of searching -- a
project I don't have time to pursue right now -- but they are out there.)


> That is not to say it hasn't been
> done.  It is to place this length for C-88 as a very great exception--and
> most likely in the category of  a mistake.  If anyone has data to show
> otherwise I'd very much like to know about it. I did have data once for a
> player upright sent to me for rescaling with a C-88 number this far off.
> It turned out to be simply an error in measuring by the technician. This
> happens all the time.  He wasn't aware of the proper places to measure
> speaking length.
>
> If C-88's speaking length has really, actually ended up at 58.7mm, I'd
> guess that multiple cumulative errors have occurred in the placement of;
> the pins on the bridge, the bridge on the soundboard, and the
> pinblock/plate in the piano.  For C-88 to be BEYOND acceptable parameters
> by almost 7 mm  indicates either a combination of  errors in the same
> direction by the rebuilder OR one big design screw up at the factory.

I would agree that coming up with a speaking length at C-88 of 58.7 mm was
probably the result of an accumulation of errors. I was not trying to determine
why or how the piano got there -- or to justify it -- I was just offering some
advice on what to do about it now that it is there.

By the way, does the above mean that you have now established an outside limit
of 52 mm for C-88?


> Yet, if it breaks, it is because this amount of  tension has actually
> been reached somewhere between two friction points,specifically in this
> case between the tuning pin and the top updraft point on the plate. So
> *functionally* the  problem in unsolvable.
> By reducing the friction as you have suggested the rebuilder can
> compensate for the thin working margin here.   I'd rather doubt long term
> success here....

> Del, it is *functionally* too high.  Theoretically not too high...?
> I'd say yes, theoretically too high also, because of friction.
> Michael, I'll be interested in your Baldwin data.

> David Sanderson
>

Well, as I said, I was not defending the notion of setting the speaking length
of C-88 at 58.7 mm, simply offering some advice on how to cope with the
situation as it existed. And pointing out, by the numbers involved, that while
this case is on the outside limits, it is not necessarily impossible. The
alternatives are to relocate the V-bar -- rather difficult to do -- or move the
bridge -- a bit easier, but still not easy.

Regards,

Del