At 1:38 PM +0200 8/28/03, Richard Brekne wrote:
>This thingy about plate height being the determinant for capstan
>placement has been vaguely put up a few times in the past couple
>years and I have yet to get a finger on exactly how that works out.
>Just what, step by step proceedure do factories use to get from
><<plate height>> (over keybed ?) to capstan placement ?
It's not the plate height, rather the front to back location of the
plate cause the problem. Apparently the method used by both Steinway
factories to locate the block on the inside of the rim results in
wide variations in block width. This is witnessed in the sometimes
1/2" range in thickness of the felt stuffed between the back flange
of the plate and the inside of the front stretcher (arising as it
will from front-to-back motion in the location of plates from piano
to piano).
If in your part of the world, you see more Hamburg than NY Steinways,
you may not run into actions disadvantaged by this phenomenon. The
long-standing explanation for the difference between the two
factories, in action set-up resulting from this, runs like this. In
Hamburg, the top action and the keyboard are indexed together, and
when #88 Strike wants to move inwards because of a wider block, the
action and keyboard both move deeper into the action cavity together,
to follow strike #88. Because they move together, the rep cushions
location above the keyboard (and thus the key ratio)remains
undisturbed.
In NY, the keyboard is indexed to the arms of the case (fixed
regardless of where the block may put the plate in any given piano),
and the top action is indexed to Strike #88. On a piano with fat
stretcher felt, the action moves into the action cavity while the
keyboard stays put. The cap line is indexed downwards from the rep
cushion, which in this case would be moving (with the action) away
from the keyboard balance pins, thus increasing the KR and FWs.
Some five years ago, NY Steinway announced that they had solved what
was an inconsistency in KRs from piano to piano (a problem which
Hamburg never had), and from what I've seen, they actually have. They
never described it as a problem related to stretcher felt thickness,
but that's where they had to have fixed it. In the procedure by which
the plate settles in, front-to-back, while fitting it to a pinblock
already glued into the rim.
As near as I can tell, Steinway is the only factory which had this
particular problem. (That is, among those who should know better.)
Bill Ballard RPT
NH Chapter, P.T.G.
"No one builds the *perfect* piano, you can only remove the obstacles
to that perfection during the building."
...........LaRoy Edwards, Yamaha International Corp
+++++++++++++++++++++
This PTG archive page provided courtesy of Moy Piano Service, LLC