[CAUT] damper touch weight

[David Skolnik]

Dear Mark -
If you produce a 1.5 -2:00 hour video of this operation, I will 
promise to watch it (and learn), in real time.  Obviously, it would 
need to be edited for any overly (not Oversly) colorful language.
Regards,
David Skolnik
Hastings on Hudson




At 12:53 PM 12/10/2010, you wrote:

>With practice, it's possible to remove the dampers & d.action, 
>clean, treat friction, check centre-pins, tighten leads, treat wires 
>and guide rail, re-install and time lift, in the time it takes to do 
>a normal tuning call (1.5 -2h). Most pianos will be getting this 
>"day-spa" treatment for the very first time, and even new pianos 
>will feel remarkably better as a result.
>
>best regards,
>Mark Cramer, RPT
>Brandon University
>The Banff Centre for the Arts
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>-----Original Message-----
>From: Fred Sturm <fssturm at unm.edu>
>To: College & University Technicians <caut at ptg.org>
>Date: Fri, 10 Dec 2010 10:09:31 -0700
>Subject: [CAUT] damper touch weight
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>         In an earlier post in the friction thread, I described a 
> device I had
>imagined to measure the weight of the damper as felt at the key. I had
>a little time to spare between access to rooms, and put one together.
>I think it took me all of ten minutes. A base about 1x4x8", a "balance
>rail" scrap of 1/2" plywood, a lever about 2' long, 1/2 x 3/4" (I
>think scrap from a strip used to hold hammers in place during
>shipping), a couple pedal brackets, a standard .146" balance pin. I
>glued a little scrap of wood on one end of the lever as a platform for
>weights - not really necessary, but nice - and then drilled a hole in
>the lever at the balance point. A couple drywall screws to hold the
>brackets, driven in with an electric screwdriver.
>         It works very nicely. I tried it out just to see what I'd 
> find, and a
>couple things jumped out at me. First, there is quite a bit of force
>needed to push trichord dampers out of the strings - as much a 5 gm.
>Even when trimmed nicely and precisely to the bottom of the strings
>there is a significant amount, though the difference between well-
>trimmed and not trimmed is noticeable, also between well-trimmed and
>just shy of well-trimmed (0.5 mm below the string line). On the
>concert instrument, where I have taken a fair amount of trouble to
>have the dampers well-regulated in all ways, I found a range from
>about 20 gm to over 30 gm top to bottom, and some zigzagging along the
>way in the 5 gm range. On a B that I had replaced action parts and
>damper felts on, but had only slapped the dampers in and regulated
>them for lift and to be sure they damped (fine-tuning put off until
>time allowed), I found much larger zigzags, 10 gms from one to its
>neighbor in a quick sampling. I suspect a lot of it had to do with
>some wires leaning on bushings, others not, but won't know until I
>have time to look more carefully.
>         Bottom line, I think this is a good thing to look at, a significant
>element in the touch of a grand.
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>PC100011.JPG
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>PC100015.JPG
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>PC100017.JPG
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>Regards,
>Fred Sturm
>University of New Mexico
>fssturm at unm.edu