[pianotech] shift shim

[Delwin D Fandrich]

First I’d want to know why there is a ½” gap in there.

 

With new leather pads of appropriate thickness on backs of the pedals and
the end of the shift lever, new under-pedal felt, etc.—you did replace all
that stuff, didn’t you?—if there is still that much of a gap I’d be looking
for a reason. The typical shift lever has a ratio of approximately 4.5:1.
That means if the action (keyframe) is shifted 0.1” or so to the right the
end of the shift lever under the pedal rod will be off by 0.45”. Or, if the
keyframe shift block (clutch?) is worn by that much the shift lever under
the pedal rod will also be off by 0.45”. 

 

Before you simply start adding leather spacers to the long end of the shift
lever you might want to be sure there is enough room between the top of the
lever and the bottom of the keybed. I’ve come across more than a few pianos
with shift levers knocking against the bottom of the keybed because some
tooner just added spacers of some kind to the end of the shift lever when
that wasn’t the problem.

 

ddf

 

Delwin D Fandrich

Piano Design & Fabrication

6939 Foothill Court SW, Olympia, Washington 98512 USA

Phone  360.515.0119 — Cell  360.388.6525

 <mailto:del at fandrichpiano.com> del at fandrichpiano.com —
<mailto:ddfandrich at gmail.com> ddfandrich at gmail.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of tnrwim at aol.com
Sent: Sunday, November 13, 2011 9:14 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] shift shim

 

I've rebuilt the piano, The old leather on the trap system has been removed
and replaced with new leather. The cavity where the shift pedal activates
the action is all there, and doesn't look worn out. The action shifts
correctly. It's just that when you press the shift pedal, there is about
1/2" of lost motion. I can, and have, added another layer of leather, which
reduced the gap, and the shift does move over a little sooner. (It stops at
the action shift screw. 

 

My question was if anyone has ever shimmed the action cavity to take care of
the gap, or is adding leather the best solution?

 

Wim 

 

 

-----Original Message-----
From: Ed Foote <a440a at aol.com>
To: pianotech <pianotech at ptg.org>
Sent: Sun, Nov 13, 2011 3:09 pm
Subject: Re: [pianotech] shift shim

     I think most shift, (assuming we are talking about the una corda),
problems I have seen have been because there is a leather pad that is torn
off the trapwork. There is supposed to be a leather pad glued to the screwed
on wood inlay that is on the shift lever.    Otherwise, there is something
that is holding the action too far to the right, creating a large gap
between the top of the shift lever and keyframe.  

    And then there is the gap caused by the keyframe having been eroded and
crushed where the shift lever contacts it.  I have always inlaid a piece of
end grain ebony when rebuilding a keyframe and it has this problem.  

 

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

 

 

 

The shift on my S&S has about a 1/2" - 5/8" gap. Should I shim the action
frame or add leather to the shift lever at the pedal rod?

 

WIm

 

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