[pianotech] Kawai parts problem

[piannaman at aol.com]

 Gregor,

That was an assumption on my part, not based on any empirical evidence....


 


Dave Stahl, RPT
Dave Stahl Piano Service
dstahlpiano at sbcglobal.net
dstahlpiano.net

 


 

-----Original Message-----
From: Don Mannino <donmannino at ca.rr.com>
To: pianotech at ptg.org
Sent: Mon, 5 Jan 2009 6:15 pm
Subject: Re: [pianotech] Kawai parts problem
















Gregor,


 


Bruce is correct - a hole in a piece of normal wood 
behaves like the plug of wood that used to be in the hole before it was 
drilled.  The hole gets larger when the piece of wood expands with added 
humidity.  Pinblocks don't behave this way in most cases because of the 
laminations and the nature of the compressed fibers from the very tight fit of 
the pin.


 


There is no problem with Protec on the Kawai action 
parts.  There is a problem using some petroleum based products on ABS 
parts, though, as it can cause chemical weakening of the composite.   
So silicone and naphtha is a bad thing.  Protec will not cause the bushing 
to swell, because it does not contain water as far as I know.  I don't know 
of anything except water which will make the bushing swell and get 
tight.


 


I am not fond of using lubricants in general, though, so I 
usually do not recommend using any lubricant to free up action 
centers.


 


Don Mannino


 



  
----- Original Message ----- 

  
From: 
 
 Gregor 
  _ 

  
To: pianotech at ptg.org 

  
Sent: Monday, January 05, 2009 8:56 
  AM

  
Subject: Re: [pianotech] Kawai parts 
  problem

  


Interesting topic. Don, Dave Stahl mentioned that you advised 
  not to use Protec for Kawai actions. Dave´s assumption is that the carbon 
  hinders the liqiuid Protec to come out of the bushing. As a consequence, the 
  liquid lets the bushing swell and results in stiff centers. At least this is 
  the way I understand Dave´s statement. Don, could you please tell me if that 
  is correct? Or is there another reason for not using Protec in Kawai 
  actions?

And another statement strikes me reading Bruce´s article about 
  the "hole truth": Bruce, you say that a flange hole gets bigger in humidity. 
  Is it not the other way round? I thought that humidity lets the wood swell and 
  therefore the hole should get smaller. But it might be that I understood your 
  article in the wrong way as English is not my first language. Could you please 
  explain why the hole gets bigger in 
humidity?

Gregor



 

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