Warped Action Parts

[Farrell]

Still looking for any good info on this, but I think I have solved my
problem this time. I was measuring the back action frame feet for being in
line/level, and then checking the front feet. I was not checking for twist.
Such a thing is hard to evaluate. If you simply lay the stack on a flat
bench, the weight of the action itself will tend to flatten it. Fortunately
I have a big, flat sanding block. Real big. Like six feet long by six inches
wide, and super flat. I put huge 96-inch sanding belts on it to sand big
things flat. I took the belt off and stood it and the stack on end. Then the
warpage and twist was evident. Warping to lift the center up and screw up my
key leveling, and twisted, so that one back foot on the bass end was way up
in the air (0.075").

Now I guess what I will do is put the action frame up to my sanding block
and measure for twist, and then put it in the keybed and measure deviation
of stack contact points for level from bass to treble. Add these deviations
to the measured values for the stack feet, and then make shims.

This is B.S. But it is a good exercise in the learning process. I'm really
learning why many experienced techs will fully rebuild a piano, but don't
want to do patch-up work on an old worn-out piano. The more I do this kind
of work, the more I am understanding their point of view. Maybe someday when
I can afford to turn away frustrating work!  :-)

Oh, well. Back to Mr. Termite Chow.

Terry Farrell

----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: Tuesday, June 26, 2001 5:21 PM
Subject: Warped Action Parts


> Does anyone have any good tried-and-true methods (or any good guesses) for
> aligning/leveling a keybed, keyframe and stack? I'm trying to do a
> regulation on the Knabe I replaced the keybed in. Keybed is dead flat. I
> have put excellent straight-edges every which way on it and it is very,
very
> flat. My trouble arose when I leveled the keys on a very flat bench with
the
> action clamped down (back action frame rail bows up). Put stack on after
> leveling, put in piano, and keys were way low in middle. Turns out not
only
> is the keyframe warped up, but the hammer and wippen rails are warped
> upwards in the middle also. So when you attach the stack to the keyframe,
it
> pulls up the middle of the keyframe even more.
>
> We are talking about a good (well, depending on how you look at it) 0.060
> inch gap between a flattened back action frame rail and the center action
> frame foot (front and rear) - lesser on others and zero at ends. Obviously
I
> can just shim under the feet, but even here I get some conflicting
> measurement results. I have even stood everything on end when measuring
> warpage to eliminate the straightening effect of gravity, but then when I
> lay it out on the flat bench, I get different measurments - not just a bit
> less or more, but rather the lowest foot is now the highest foot.
>
> Is there any hope here. I know very well what the heck the piano needs: a
> new piano, or at least a new action frame, keys, and top action (would at
> least solve this problem). But the plumber/electrician that is in full
> charge of the fate of this hospital-owned piano does not feel it real wise
> to spend much money on it. I'm just trying to get the %&*# termite-eaten
> thing to play!
>
> Thanks for any input. Anyone got a shoulder to cry on?
>
> Terry Farrell
>
>