[pianotech] Underlever Spring Tension Measurement

A440A at aol.com A440A at aol.com
Wed Jul 28 15:42:34 MDT 2010


Greetings, I wrote:
   I set the underlever springs by measuring several along the length and 
marking them with a spot of chalk after setting them to the appropriate 
tension. Turning the whole assembly upside down, I give it a slight up and down 
shake.  It is easy to then set the entire rack to the index underlevers by 
simply pushing the levers down a little until they also move the same amount 
as my guides.
 
And Dean says: 
> I'm trying real hard, but I can't visualize your method of adjustment
>  
>    I have several springs along the length of the tray set to the minimum 
spec. Turning the assembly over, the underlevers are supported by the 
springs.   I then weaken all the springs with slight pushes downward, so that with 
a gentle up and down movement, they all bounce the same as the guides.   I 
taper the strength so that the amount of spring gradually diminishes   as I 
approach the unsprung section.   
hope that helps.
Regards, 
Ed Foote
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