Bass hammer checking

[Phillip L Ford]

On Fri, 15 Mar 2002 10:40:21  
 antares wrote:
>
>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,
>
Antares,
I wonder if there is something else to add to the list.  I have speculated that one
of the reasons for the poorer checking as you go down the scale is the presence
of heavier dampers.  Some of the pianos that have the most trouble with checking
also seem to have the heaviest dampers.  I've thought that perhaps the damper
was being thrown up by the key, hitting the stop rail, and bouncing back down
against the key with enough force to slightly move the key and throw the hammer
out of check.  Do you think there is anything to this?

Phil F


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