[pianotech] Hammer Line Issue

[Israel Stein]

Hello,

I have followed this with a great deal of interest, and at this point I 
feel myself compelled to chime in. The hammer bobbling, or dithering or 
whatever you want to call it (assuming that this is strictly a 
regulation problem) can be caused by either the keydip being too 
shallow, or the strike distance being too long. If the problem is the 
keydip, this in turn could have been caused by the key level having 
dropped (due to settling of the balance punchings) or  whatever other 
reason. Before deciding what to do, one should:

1. Measure the strike distance. If it's 2 inches - the problem isn't 
keydip.
2. Measure the keydip. If it's 7/16 in. (11 mm.) or more - I wouldn't go 
any deeper...
3. Check the key level with relation to the keyslip. Is there a "dip" in 
the middle of the keyboard? Well, then you level the keys before going 
any further. Of course to do this, one needs to know the parameters for 
key level with relation to the balance pins, key slip, front pin, etc.

Matthew, like the man said - learn how the action works and how the 
various functions interrelate. And get familiar with plausible  
regulation specs. Get the manufacturer's specs and see if the piano is 
anywhere close to them.

Just telling Matthew to "do this" and "do that" without any context 
doesn't do much good either for his learning curve or for his client... 
Often this sort of approach will solve a problem at the cost of creating 
two new ones. Sort of like digging a second hole to bury the dirt from 
digging the first one.

Israel Stein
>
>
> ------------------------------------------------------------------------
>
> Subject:
> Re: [pianotech] Hammer Line Issue
> From:
> "Tom Driscoll" <tomtuner at verizon.net>
> Date:
> Thu, 07 May 2009 19:57:19 -0400
> To:
> <pianotech at ptg.org>
>
> To:
> <pianotech at ptg.org>
>
>
> Matthew
> Good job.  As for the dithering hammers ( one of our English 
> contributors used the term and I love it!) I think someone mentioned 
> decreasing the tension on damper lever springs. This was for the 
> Yamaha actions that have the problem that Matthew describes. 
> Listees'  am I remembering that correctly?
>  I'm also with  David  on no more than 1/8th  letoff combined with 
> an increase in dip.With letoff more than 1/8th the hammer has to be 
> thrown across too far a distance to allow soft play. The  increase in 
> dip - aftertouch  will move the top of the jack away from the 
> returning butt and help with the symptom.
> I think Ron N. mentioned that there is a geometry problem with the 
> Yamaha jack that leads to bobbling hammers on a soft blow. I wonder if 
> the Kawai has the same issue. Again ,good job. I'll bet they were 
> pleased with what you accomplished.
> Tom D. 
>
>
>     Bring the letoff back to 1/8" and increase the dip so the hammer
>     doesn't bounce off the jack.
>
>      
>
>     dp
>
>      
>
>      
>
>     David M. Porritt, RPT
>
>      
>
>     I serviced the Kawai today.
>
>      
>
>     I adjusted the capstans, letoff and checking.  It went really
>     well.  Although, when I was doing the letoff, I couldn't get the
>     piano to do 1/8''.  When I did 1/8'', and then pressed the note
>     pianissimo, it would double strike, so I did just a little bit
>     more letoff and the issue resolved.
>
>     Here is a bigger question.  After I finished, I played a Bach
>     piece, and one thing I did notice was that it was somewhat
>     difficult for me to play really soft.  Is there something more I
>     need to do to obtain this?  Or, maybe to state it better, I could
>     play "forte" and even "piano", but to obtain a "mezzo piano" was
>     difficult.  What can I do that would help with the dynamics?
>
>      
>
>     Thanks again for all your help,
>
>     *_TODD PIANO WORKS_*
>     Matthew Todd, Piano Technician
>
>      
>
> ------------------------------------------------------------------------
>
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