Teflon bushings: (was Re: Pinning on new flanges}

[David's Email]

And the centers were tight because of ?   I rest my case...;-]

David I.



----- Original Message ----- 
From: <A440A@aol.com>
To: <pianotech@ptg.org>
Sent: Wednesday, August 25, 2004 7:27 PM
Subject: Re: Teflon bushings: (was Re: Pinning on new flanges}


>
> << I was under the impression that one of the problems with teflon was 
> wood
>
> swelling and squeezing the bushing thus tightening the flange... is this
>
> another urban legend? >>
>
> Not really. The wood distorts in response to humidity changes.
>    If the hole was round when the wood is dry, it is oval when the wood
> absorbs more moisture,(wood changes far more across the grain than with 
> it).  If
> the hole is round when the wood is damp, it becomes oval when the wood 
> dries
> out!
>   Teflon bushings require so little compression to give the proper 
> friction
> that any distortion that causes loss of round will allow noise.  The 
> smaller
> teflon used in the earliest actions would distort and stay that way.  I
> recently repinned the damper action of a 1962 M that used cloth in the 
> action, but
> teflon in the damper assembly!  I repinned it because it was too tight to 
> allow
> proper damping.  It had never been worked on before, Go figure...
> Ed Foote RPT
> http://www.uk-piano.org/edfoote/index.html
> www.uk-piano.org/edfoote/well_tempered_piano.html
>
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