Unstringable C8, was Steinway 78183

[Kendall Ross Bean]

I'll throw my two cents in on this:

I was taught that speaking length on C-88, on Steinways and most other
pianos, should be right around 2" (plus or minus a bit, depending on whether
it is a "hand-made/hand-fit" piano or not ;-)  ). This corresponds to what I
usually see when I am restringing pianos, whether they be Steinways, Masons,
Baldwins, Chickerings, Knabes or what have you. Yes, it is often a little
over or under this figure, but for me 2" seems a good point of departure.

This corresponds with a pitch of about 4186 hz at C-88 (or tuning to A440).

A couple of sixteenths of an inch over or under 2" doesn't seem to make a
whole lot of difference, except in the percentage of breaking point/amount
of tension the wire will be at when pulled up to pitch. 

If speaking length is significantly over 2", however,(like 2.5" in the
present case) the wire is simply being asked to be stretched too tight to
achieve the required pitch, and will break. Many of the pianos I have worked
on that had string breakage problems in the high treble were found to have
speaking lengths that were "too long", i.e. corresponding to very high or
maximum percentage of breaking point when at pitch. Moving either the bridge
or terminations so that the speaking length was shorter was really the only
solution, if you wanted to be able to tune the piano to pitch.

Significantly under length causes another problem. If the string speaking
length is too short, breakage is not usually a problem, but the string
simply may not sound very good, being at too low a tension.  

It doesn't matter what size wire you use, they will all break if the
speaking length is excessive. A larger diameter wire simply requires more
tension to be able to be pulled up to pitch, so any benefit in trying to use
"thicker wire" is automatically cancelled out. This is a basic rule of piano
string physics. If a size 12 1/2 wire breaks, a size 13, a size 14 and a
size 16 will also break. It seems, however, technicians unaware of this
simple rule of physics always have to go through the motions of trying a
larger diameter wire, and still having it break, in order to learn this
simple fact. (Go ahead, ask me how I know...)

Like Ron N. said, it is the speaking length that is the problem here.

After having rebuilt 100's of previously unrebuilt Steinways, from all
periods, in our rebuilding shop, we learned that you simply cannot trust the
factory workers to get the bridge placement right (or even close, in many
instances)(or plate location as well, see below). You cannot assume that the
factory workers "knew what they were doing," anymore than you should assume
that subsequent rebuilders "knew what they were doing."

In one original condition/unrebuilt Steinway "L" from the 70's we worked on,
the back side of the top part of the treble bridge was actually up against
the plate. Some of this, I think, may have had to do with the way they fit
the pinblock to the plate flange at the factory at the time, which was done
with the pinblock in the piano (i.e. already fitted to the stretcher and at
the ends), -or at least, that was the way I observed them doing it when I
went on the "factory tour" around 1990. The plate was lowered into the piano
with graphite on the plate flange, and the worker placed go-bars between the
plate and the "ceiling" to hold the plate down against the pinblock and
inner rim ; the pinblock was then flexed up and down with a lever from
underneath against the plate flange to transfer the graphite to the
pinblock; the plate was then hoisted out;  and then the high spots on the
pinblock were ground down with an air grinder to fit. As I remember, all
this was done without removing the pinblock from the rim. Evidently, in this
process, it was possible to remove too much material from the plate flange
edge of the pinblock in the process of mating it, which effectively moved
the plate forward (i.e. closer to the stretcher) and increased the speaking
length of the strings (since the soundboard and bridges were already fitted
to the rim and in place as well). The plate location apparently depended on
how far the worker ground down the pinblock in the mating operation. Not so
much a problem in the mid range or the bass, apparently, but a few
sixteenths of an inch off in the high treble, on those short strings, was
critical. -Especially in this case, where the plate ended up rubbing against
the back of the bridge. (I have pictures if anyone wants to see them...)

This is an example of where a factory foul-up can make major problems for
technicians down the line, and it happens all the time. As often as not, the
piano is out of warranty by the time an alert technician finally discovers
the problem, although in my book, major structural boo-boos of this sort
should transcend normal warranty limitations.

I always measure C-88 if there is ANY question, and if it is significantly
more or less than 2", I start looking for bridge or plate placement
problems.

Yes, it certainly does appear that there is a lot of variation in the
"standard piano of the world". The question is, why?

I think part of the answer may lie in the fact that the pianos are indeed
designed by scale designers and engineers, but they are not always around to
check things when the piano is being made.

Ken Bean

PianoFinders 

-----Original Message-----
From: A440A at aol.com [mailto:A440A at aol.com] 
Sent: Tuesday, October 07, 2008 6:39 AM
To: pianotech at ptg.org
Subject: Re: Unstringable C8, was Steinway 78183

Greetings, 
   I have several of my pianos in the house right now. 
A model S, #333xxx.  The C88 measures 2.25 inches!  
A model M, serial number 258xxx.  C88 on it measures exactly 2 inches. 
An upright, model K # 78xxx    C88 measures 1 15/16"
A model A # 78861   measures 1 13/16


It appears that there is a lot of variation in the "standard piano of the
world". 

The upright has the most responsive sound at C88.  Maybe some of you
scale/board gurus can shed some light on this? 
Regards,

Ed Foote RPT
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html
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