[pianotech] Hammer Flange Friction

[Don Mannino]

It's hard to be sure, but most likely the wool fibers have been packed into
an unstable position by the swelling / shrinking process, and when you work
the parts the fibers are moving a little out of their packed-down positions,
thereby adding pressure on the pin.

 

I would suggest that easing the hammer center friction may not be the best
answer to better performance in this case.  I am not familiar with the
particular action you mentioned, so forgive me if it is an especially
non-standard design, but most vertical actions perform better with the
hammers a little on the snug side.  If you are not getting good key return,
the hammers should not be the part that does it for you.

 

Look to the spoon / damper lever felt for excess friction, and of course
wippen flange and capstan.   If the notes return better with the damper
pedal down, it is likely the damper lever felts and spoons.  If the key
return is worse with the pedal down, it is likely the wippen flanges or
capstan friction / worn cushions slowing things down.  Or of course simply
insufficient weight at the back of the key as you alluded to.

 

Don Mannino

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Floyd Gadd
Sent: Friday, June 04, 2010 5:05 AM
To: pianotech at ptg.org
Subject: [pianotech] Hammer Flange Friction

 

I run into a number of 60's vintage consoles with Sterling (Canada) actions.
As a rule, keys are not back-weighted, hammer return springs are strong,
damper lift is early, and touch is unpleasant.  Hammer pinning is
tight--pulling a hammer and swinging it will yield 1, 2, maybe 3 swings.

 

I'm applying 85% methanol, 15% water to the flanges, and applying heat with
a Damppchaser humidifier bar.  Once this is done, persistent and vigorous
working of the assembled flange will yield 5 swings (I would aim for 7 in
the drier season.)

 

Here's my question:  After letting the alcohol-water solution evaporate, an
immediate swing test yields a slightly better result than before
application.  An initial vigorous swing/shaking of the hammer brings the
number of swings DOWN, not up.  What's up with this?  If I apply pressure in
various directions while working the flange slowly, I can get the friction
to target, once I've done this I use Protek CLP, with the intention of
enhancing the work done by cleaning and protecting the pin.  (CLP without
the water/alcohol treatment does not provide a lasting result.)

 

I think this is still faster than repinning the whole set, and I imagine
that the water/alcohol treatment improveds the state of the bushings, but
that increase in friction with initial working doesn't make sense to me.
Any ideas what is going on?

 

Floyd Gadd

Manitoba Chapter

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