Optimum Length of Pianos

[Delwin D Fandrich]

----- Original Message -----
From: "Bob Sutton" <bsutton@swbell.net>
To: "Pianotech-Digest" <pianotech-digest@ptg.org>
Sent: August 27, 2002 10:36 PM
Subject: Optimum Length of Pianos


> Does anyone know how the length of a concert grand piano was determined?

Someone might. I don't, but....


> Was approximately 9 ft. decided on by certain formulae or was it the
> most convenient and maximum size that was movable?

There is no formula that I am aware of. But, as the length of the piano gets
longer the problems of building it increase exponentially.

And, as long as we're talking about gray iron plates.... The so-called
'modern' concert grand piano was built around a unified cast gray iron
plate. Piano plates of any size are difficult to cast without a lot of
warping taking place during cooling. Two massive end pieces connected by a
network of long, thin bars is a recipe for problems. This is especially true
with the extreme overstrung designs which seem to be an essential element to
our concept of a 'modern' piano. To some extent this warping can be
controlled by building a reverse warp into the pattern. As the casting gets
longer and longer, however, the problem becomes increasingly severe and less
controllable. I expect foundries simply reached some practical limitations
at about this point.

There are some pianos longer than the 'standard' 275 to 280 cm. But they are
not without their problems. The next time you sit at the keyboard of a 308
Fazioli sight across the back of the plate and you'll probably notice the
back right-hand (from the pianists perspective) corner of the hitchpin panel
pulling up. Well, not pulling up, exactly, that's the way it ended up during
cooling. This is not a structural defect, necessarily--the plate is quite
strong enough for the task--but it does illustrate one problem with long
unified-construction cast piano plates.

To reliably make a dimensionally accurate and stable plate much longer than
that used in the 275-280 cm concert piano some other method of construction
will have to be used. It could easily be done using a built-up plate if
there was any incentive to do so. And if our sense of tradition would allow
it.

Del