[pianotech] Replacing dampers on a Steinway Upright

[Berley Firmin II]

Hi... I'm in need of any information on a Knabe upright piano Serial # 53878. AAny info would be appreciated - manufacturing date etc. My copy of pierces is packed away pending building of new workshop.
 
                                   Thanks, Michael

--- On Thu, 2/17/11, Encore Pianos <encorepianos at metrocast.net> wrote:


From: Encore Pianos <encorepianos at metrocast.net>
Subject: Re: [pianotech] Replacing dampers on a Steinway Upright
To: pianotech at ptg.org
Date: Thursday, February 17, 2011, 1:26 PM






I just noticed that Brooks, Ltd. Sells an upright damper kit (TVDK)  made by Tokiwa (page 22 of catalog) that might be well suited to modernize old upright damper systems.  I have not used it, but it is similar to what I have used in the past, and would be worth the try.
 
Will Truitt
 


From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Joe DeFazio
Sent: Friday, February 11, 2011 2:51 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Replacing dampers on a Steinway Upright
 



From: "Encore Pianos" <encorepianos at metrocast.net>

Date: February 11, 2011 5:24:49 AM EST

 

You are welcome, Joe.  I measured the renner bass dampers yesterday – 57 mm long.  Adequate for any 52 incher.  

 
Thanks.





The length of the first 2 or 3 tenor dampers is governed by the bass strings at the bottom and the need to clear the hammer at the top.  

 

Yes, I do understand that.  I was a bit more interested in the length of the dampers just above the break, where the crossing bass strings are no longer an issue.  That's where we have an opportunity to change length, and where there is most likely a point at which an increase in damper length becomes counterproductive.  I would like to gain a clearer idea of where that point lies.  I guess experimentation and measurement of well-functioning dampers will be the way I can find my answer.




I also think that wooden blocks are in the tenor section as they add a bit of mass, which aids in damping.  If memory serves me, you can get brass barrels from Pianoforte supply, but they are expensive.
 

I hadn't thought about the mass of the damper block in uprights, but it makes perfect sense.  I will look into the brass barrels, which I didn't know existed.  

 

Since the weight sits on the action rail via the centerpin, the added weight shouldn't affect touchweight (as it would in a grand damper head with the sustain pedal not engaged), but it will add a slight inertial resistance as the spoon starts to move the damper assembly.  I'd imagine that that would be negligible as compared to the damper spring's force in resisting the spoon.

 

I suspect that there are many techs like me out there who do action rebuilding and parts replacement on grands at least ten times as often as on uprights.  So, my skills and thinking are much more developed in the grand area, and this is a good opportunity to give the upright a few more dedicated neuron connections.

 

Thanks again,

 

Joe DeFazio

Pittsburgh
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