[pianotech] Hammerheads resting on Backchecks when hammer is at rest

[David Ilvedson]

I would regulate the blow distance, letoff/drop to specs.   Then check that the hammers are checking properly, i.e. the backcheck not to close to the hammer tail.  When hammer is moved through letoff/drop the top of the backcheck should be just a little bit below the hammer tail.   Since you are not going to do any big repairs such as lower backchecks, if that was the problem, I'd make the hammer blow a little closer that spec to solve the problem.   You don't want the hammer touching the backcheck at rest.

David Ilvedson, RPT
Pacifica, CA  94044

----- Original message ----------------------------------------
From: "Mark & Janine Davis" <pianofortetechnology at saol.com>
To: pianotech at ptg.org
Received: 4/19/2010 11:29:36 AM
Subject: [pianotech] Hammerheads resting on Backchecks when hammer is at rest


>Greetings List

> 

>I am needing to regulate an old C. Bechstein grand which has had some work
>done on it in the not so distant past.  The grand is about 100 years old.
>What I plan to do is 1. Lubricate, 2. Align, 3. Regulate/Adjust wherever
>necessary as best as possible.

> 

>One thing I am not sure of is the hammerheads are resting against the
>backchecks when at rest, even to the point that if you push the backcheck
>away from the hammer, the hammer drops back down onto the rebound cushion.
>I am aware that the hammerblow needs to be set and that by doing this the
>shanks will be held up and off the rebound cushion and that the capstans
>will need to be adjusted in order for this to take place.

> 

>The little experimenting that I have done is to check if the hammer still
>rests against the backcheck even when the capstan is adjusted so the hammer
>is being held up and off the rebound cushion by the wippen/repetition
>lever/jack and not by the backcheck, but the hammer is still resting against
>the backcheck.  This problem is in the middle and bass sections of the
>piano, the treble does not seem to have this problem.  

> 

>The piano action with the keys and keyframe were removed from the piano and
>brought to me after the keys were rebushed.  I do not know what the
>situation will be once the hammerblow is worked out and adjusted for at the
>piano.  I do not think that it will be different?

> 

>Are the hammers resting against the backchecks a problem?  And if so, how do
>I sort it out?

>Your advise will be much appreciated!!!

> 

>Thank you, 

>Best regards,

>Mark Davis                    

>