[pianotech] shift shim

[Tom Gorley]

I think someone already mentioned this but Del's answer again reminds me again about checking that the lyre is not pulling apart, usually near the pedal box.
   ---Tom Gorley

>    Tom Gorley
> Registered Piano Technician     
>       





On Nov 14, 2011, at 3:04 PM, Delwin D Fandrich wrote:

> 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
> del at fandrichpiano.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
> 
>  

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20111114/66846dd2/attachment-0001.htm>