key-frame return spring

[Sambell, Ted]

Hi Mark,

Sometimes the contact points wear a flat spot on the keyframe return
springs, and it might help to round them over with an emery cloth file then
polish them on a buffing wheel. It happens more commonly on the pedal trap
lever flat springs which were common on old grands. I discard them and fit
coil springs instead. Of course, this cannot be done with the keyframe
springs. It can be annoyimg when the spring was originally fitted if it was
not partly recessed into the inner rim, because it will exert higher
pressure than is needed. It also makes it more difficult to remove and
replace the action. 

Regards, Ted
-----Original Message-----
From: David Ilvedson, RPT [mailto:ilvey@jps.net]
Sent: Tuesday, November 21, 2000 9:46 PM
To: caut@ptg.org
Subject: Re: key-frame return spring


I take it you are referring to action return spring vs. treble side of the
keyframe?  I would scrap off all the DAG and use nothing but microfine
teflon powder.  DAG has a habit of falling off whenever you are over a white
carpet and is really unnecessary these days...OK maybe bridge tops.  Also
make sure that the spring itself isn't moving!

David I.


From: Mark Cramer <cramer@BrandonU.CA>
To: caut@ptg.org <caut@ptg.org>
Date: Tuesday, November 21, 2000 7:18 PM
Subject: S&S: key-frame return spring


>Hello all,
>
>Today I managed to find the elusive source of shift-pedal squeeks and
groans
>in a B, and with careful effort and attention actually made it worse!
>
>Once I had determined the cause (spring against (wooden) key frame), I
>carefully sanded the side smooth, applied a generous coat of DAG, and
>burnished with a cloth.
>
>It worked instantly, and lasted about 3 minutes!  Once the DAG was well
>burnished, it began to groan as before, but louder!  And now, in addition
to
>the fundamental, there were additional squeeks a major 3rd above and major
>2nd below!?
>
>At a loss, I worked teflon powder into the graphite and with vigorous use,
>the noise has not returned. Tefloning and testing the two contact points of
>the spring seperately helped verify the source, as one "note" of the
>non-musical "interval" disappeared with the first treatment, then the
>remaining two.
>
>I fear this remedy will not last though, so what is your favourite tried &
>true, long-lasting, never-fail, method?
>
>Thanks for your suggestions,
>
>Mark Cramer,
>Brandon University
>
>
>