Warped keyframe

[jolly roger]

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Greeting Jon,
                         I doubt it, for two reasons.   1.   The rail is not
very thick back there, so you can't make a significant saw cut.  2.   The
action brackets and frame has a lot of influence on the position and shape of
the rail.
Remember these are very soft wood frames.

  Several solutions.

Before starting, remove stack and keys, install the frame to pin point where
the problem is happening.  ( Twisted action rails can be the cause of the
problem. )   I did not find that problem in 5 mins.  (Grin)
If the frame is now flat. you have a problem with action stack bowing the
frame.

1.  Shim the feet of the action brackets with veneer. To overcome the bowing.

2.  Shim the frame in the dag areas and sand for a good fit and good unacoda
operation.  The dags will hold the frame down.

3.  If the frame is badly bowed, shim the underside of the crown with veneer
and sand to fit.

4.  Minor knocking just sand the back frame.


With Yamaha's I have bedded the back frame by changing the order of bracket
tightening.  If it is knocking in the centre. Tighten the outer brackets
first,
then the middle ones.  If it knock's on the outer area then tighten the centre
brackets first. 

Fun and games.
regards Roger







At 04:47 PM 2/12/02 -0500, you wrote:
>Hi Roger,
>Would this method also work on a Yamaha back rail?  I have a similar 
>problem on a C3 - the ends are well-bedded, but the area in the 
>middle is rather uncooperative.  There aren't any kerfs, save the 
>cut-out for the una corda lever.
>
>Respectfully,
>Jon
>
>
>
>>Hi Victor,
>>                  A healthy saw kerf half way through the rail, at 
>>the top of the crown, of the warp.Two kerfs, from the underside 
>>about 6" on either side of the crown kerf.  Shim the lower kerfs to 
>>straighten the frame.  Then bed the frame in the traditional manner.
>>Warped frames have a nasty way of moving with humidity changes, the 
>>high side saw kerks, helps to stop any warping upward movement if 
>>they are left open.
>>Regards Roger
>>
>>
>>At 07:41 AM 2/11/02 -0500, you wrote:
>>  >Heelo all,
>>  >
>>  >I need your help in deciding what to do with a Howard #550 (Kawai) Ser#
>>  >2905365.
>>  >They key frame is warped upwards at the center of the front rail. I am
not
>>  >sure if the balance area or the back part of the4 frame is also warped.
Did
>>  >not get the chance to look at it; and could not really figure out how to
do
>>  >it in a small apartment.
>>  >
>>  >What is the best remedy.
>>  >
>>  >Thanks
>>  >
>>  >Regards.
>>  >
>>  >Victor Belanger
>>  >Somerville, MA
>>  >
>
>Jon Ralinovsky
>Piano Technician
>Department of Music
>Miami University
>513/529-6548
> 

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