Bass hammer checking

[antares]

Hello Phillip Ford,

To my knowledge it does have to do with the force of the repetition springs,
the angle of the back check and the condition of back check leather and
surface of the tails.
As the springs in the bass section are heavier they are also more difficult
to control. Most of us have experience with this disturbing behavior of the
first bass hammers.
Furthermore, it might be very well possible that the action is in a
different position on the bench so that the hammers may check at a slightly
different angle than in the piano.
I would recommend this :

1. roughen up the surface of the hammer tails with a file or a knife
2. make sure that the back checks have an angle of 72 degrees
3. make sure that the hammers in general check as high as possible
4. make sure that the leather of the back checks is 'ok'
5. make sure that the rep. springs are not tight but do their work properly
without making the hammers jump
6. make sure that the height of the back checks is proper in relation to the
tails of the hammers




friendly greetings
from

Antares,

Amsterdam, Holland

"where music is, no harm can be"

visit my website at :  http://www.concertpianoservice.nl/


> From: "Phillip L Ford" <fordpiano@lycos.com>
> Organization: Lycos Mail  (http://mail.lycos.com:80)
> Reply-To: pianotech@ptg.org
> Date: Thu, 14 Mar 2002 18:45:04  0000
> To: pianotech@ptg.org
> Subject: Bass hammer checking
> 
> Yesterday I worked on an older Baldwin with a Schwander action that
> had a characteristic that I've encountered on other grand pianos,
> some having it more than others.  The hammers check perfectly on the
> bench or when the action is pulled out in your lap, but won't check when
> the action is in the piano.  This behavior is usually only noticeable in the
> low end of the scale and becomes most pronounced at the bottom.  On some
> pianos it seems that you can't get the hammers at the bottom end to truly
> check no matter what you do; make the checking shallower, make it deeper,
> groove the tail, rough up the check leather, change the back check angle,
> reduce rep spring strength to almost nothing, etc.  When I say 'truly check'
> I mean behave as in the rest of the piano.  The hammer is held
> some distance below the string when the key is down and rises
> when the key is released.  Apparently some sort of 'checking'
> is going on because even on a hard blow the hammers don't bounce back to
> the strings.  But the tail isn't really being held by the backcheck when the
> key is down.  What's the reason for this?
> 
> Phil F
> ---
> Phillip Ford
> Piano Service & Restoration
> 1777 Yosemite Ave - 215
> San Francisco, CA  94124
> 
> 
> 
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