keybed spring

[David Renaud]

  Korlore & Campbell, for a music school, one year
old, tuned twice so far.

   Call for sticky key. 

   Key is rubbing on the key slip. 

   Upon removal of the keyslip, I notice how tight the
key slip screws are, and all the powder sawdust coming
out with the screw. 

   Upon inspection the key slip appears straight.

   Placing the keyslip back, it touches the keybed
at the ends, but there is a bow towards the middle
with over a 1/16 inch gap at center. I push upward
on the bottom of the keybed with my thumb only and
watch while the keybed wood itself flexes up and down
in the center and also observe the keys rising and
falling. The keybed is a spring

   I notice that with the key slip removed the entire
middle of the piano has severly bubbling hammers.
Putting the keyslip back stops the bubbling, but 
the keyslip rubs the front of the keys. 

  I determine that the keybed is warping. The downward
pressure is forces the keyslip to torque
towards the keys. Tight key slip screws were due to 
torque of bending the keybed upwards. The dust
coming out with the screws was the light material 
developing stripped screw holes under the torque. 

  Being a squeezed emergency appointment for a  sticky
key , I comprimise by leaving one screw out so as not
to torque the keyslip and keybed together so much,
adjusted extra let off to eliminate bobbling hammers,
and said I would e-mail a report.

  I can not see a solution to this other then perhaps
putting a strip of plate steel under the keybed to
freeze it straight. With nothing but dust to screw it
into, bolts through would be required. 
 
  I can bend the keybed about with my thumb alone. 
How can one be expected to regulate that, the keybed
itself is a mushy energy absorbtion spring. 

  The first time I tuned this piano I was impressed to
find a clean sounding chinese piano that was tunable.
I am not so pleased afterall. This is bad for
business, it smells of mechnical instability,
callbacks, and unresolvable issues. I piano I actually
can not work on mechanically  

1) Steel plate?? thoughts.......
2) How many have seen this.....other solutions

  I will try to fix anything, but this looks like 
soft, spongy warping material that can not be worked
with. I feel it is a total waste of time to regulate
it, come spring everything will have changed
dramaticly. grrrrr

   Somebody is going to think up a fancy technical 
name.....accelerated keybed spring action.....and
someone else is going to think it is a good idea and
patent it.......sorry.....
 
                       Feeling dramatic
                       Dave Renaud  






 
 


  


     


 





	

	
		
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