[CAUT] Re: swelling knuckles -- old thread

[Joseph D. Gotta, RPT]

Was there a significant reduction in friction? If so did you find the
repetition springs suddenly a little too strong? I have encountered this
and had to relax the springs to alleviate double striking hammers on a
closely regulated action. This was with powdered Teflon applied to the
knuckles though so I'm sure there was no swelling involved.

Joseph D. Gotta RPT


-----Original Message-----
From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf Of
Otto Keyes
Sent: Wednesday, May 04, 2005 4:14 PM
To: College and University Technicians
Subject: [CAUT] Re: swelling knuckles -- old thread

Some time back I mentioned encountering a problem with bobbling hammers
on a
D after I had hit them with a shot of dry spray teflon, but then forgot
to
report the results.

>From some of your suggestions I was afraid I was going to have to
re-pin
everything (fairly new parts), but the pinning turned out to be just
fine.
Though I don't know how much they changed, since I didn't measure just
before the treatment, the let-off was consistently closer, so the
knuckles
had swelled just slightly.  This, coupled with the fact that the
regulating
button felt on the jack had compressed slightly, allowing it to sit just
a
bit deep under the knuckle, caused the hammers to double-strike.  Once
those
2 elements were dealt with, it settled down to work like a real piano
again.
My guess is that something in the aerosol carrier in the teflon spray
caused
the knuckles to swell just enough to cause problems when put together
with
other minor deficeincies.  I doubt that it would have caused a problem
had I
just sprayed it on the balancier & top of the jack.

Otto

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