Gregor asked about the holes getting larger in high humidity. I believe that most action center holes do get larger in high humidity. This is probably the opposite of what most technicians would expect, but for the most part I think it is correct. How to explain better... when a piece of wood gets bigger, all parts of it get bigger. Grain orientation, however, will make for more stability in one direction over the other. If the wood is stabile and has been in high humidity for a long time, the piece of wood gets bigger. All of it gets bigger. If you take a picture of an hammer flange, double the size of the image, the hole in the flange looks bigger. The examples in the article illustrate that this does happen. The balance rail hole on a key gets tighter in the winter, not the summer. Teflon bushings click in the summer, because the hole is larger then. For me this is the most important observation related to this. The Teflon does not change size. Do others on the list find more clicking Teflon in the winter or summer? I know some of you replace it all when you see it and don't live with it like some of us do. God bless you! Even with the high humidity swings we get here in the Chicago area, action centers that are in good shape do not seem greatly affected. I still think we should examine how they work and what makes them better and more stabile. At the recent PTG seminar in Chicago, Paul Revenko Jones encouraged everyone to look closer at the small parts of the piano and think about them. I agree. I am surprised when a subject like this gets so little discussion. Others here may also have done experiments like Don Mannino. (I have not.) I would rather hear folks tell me I'm wrong here than dismiss or ignore the subject. There are many great characteristics of the new types of plastic action parts and we are likely to see them more and more. It seems to me that understanding this relationship is important to well functioning actions. Bruce Dornfeld, RPT bdornfeld at earthlink.net North Shore Chapter -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090105/46c99721/attachment.html>
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