Why?

[Richard Brekne]

Delwin D Fandrich wrote:

> Roger,
>
> I certainly agree with points 2, 3 and 4.  Unfortunately, I have not found
> their pinning to be all that consistent.  I think it is probably the result of
> the graphite used.  Since graphite is somewhat hygroscopic these centers seem
> to be somewhat susceptible to variations in moisture.  We've also had more than
> a few centers simply lock up tight after periods of hard play.  About point 5
> -- I do not consider hornbeam to be a superior wood compared to reasonable
> quality hard maple.  But it sure does machine pretty.
>
> Del
>
> ------------------------------------------
>

I understood that it was generally agreed on (several years back as a matter of
fact) that graphite was found to be a definant no no in centerpin bushings.
Something about crystaline structure of graphite, some reaction to warming up after
a bit of playing causeing the freez up you mention. I regularly clean out this as
best I can and work a little teflon powder in the bushings instead.

I have used teflon powder in this way for about 6 years now and find no adverse
reactions whatsoever. I have 30 or 40 pianos I visit yearly that I have done this
to so I have been able to keep track of the results. One thing I notice is that its
much much "safer" to go with 4 swings tightness then without teflon, and definately
safer as compared to using graphite.

Suprises me that folks are still using graphite in centers

Richard Brekne