Steinway pinch

[Fred Sturm]

Mark Cramer wrote:
> 
> Please bring me up to speed on the seasonal affectation with Steinway
> key-blocks.  This is the first winter I've experienced the clatter of the
> key-frame pins within the guides.  I assume this happens when the (crowned)
> key-frame relaxes (sp?)  (summon the spelling-check police) due to dryness.
> 
My experience is not with chatter between keyframe pin and keyblock
plate (do I have the correct term here?), but the knock between keyframe
and keybed. This occurs at the outer ranges of the instrument, due to
the crown of the front rail in the Steinway design - the keyblock plates
actually pull the keyframe down into contact with the keybed. Over time,
wood shrinks or crushes in response to humidity swings. When it is dry,
the gap appears due to wood shrinkage. (Other makers, like Yamaha, bed
the keyframe to the keybed all along its length, so this problem doesn't
tend to show up - even if there's a gap between pin and plate, the frame
doesn't knock against the bed because the contours match. The Steinway
design seems to be based on the notion that the frame might warp, and
knocking develop in the middle of the keyboard. Having curvature means
the middle is always going to be in contact, and the plates pull down
the extremes.)

> I'm not sure what was meant by the cardboard shims, are we placing these
> beneath the ends of the key-frame.  I'm really wishing I could adjust the
> key-block inserts down (seasonally) to take up the gap.  Thanks for any
> clarity you can provide.

The cardboard shims are glued to the bottom of the keyblocks, factory
installation. Layers can be peeled to account for wood shrinkage, until
it's all gone. Then, if you want to use the same design, you have to
remove wood and glue a new layer of cardboard.
	Some do place shims under the keyframe - between it and the keybed.
Most commonly a business card. I do it myself in an emergency. Seems to
work just fine as stop gap.

Fred Sturm
University of New Mexico