[pianotech] Kawai parts problem

[Don Mannino]

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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