measuring key weight ratio

[Richard Brekne]

Grin... just add 20 grams to the existing front weight and subtract when 
you are finished.  Remember... Front Weight is taken at an specified 
point just under the front of the key with the key horizontally 
oriented.  A 10 gram weight placed directly over the center of the 
weight point will yeild an exact 10 gram increase in FW.

Front Weight is only <<valuable>> in terms of being a static 
measurement.  Any and all issues relating to the dynamics of the key 
during motion... inertia, compliance etc are a seperate issue of 
course.  But from a standpoint of static balance... FW is FW regardless 
of any condition behind the fulcrum.

Cheers
RicB

Jenneetah wrote:

> At 9:04 AM +0100 9/23/04, Richard Brekne wrote:
>
>> Put 20 grams on the front of the key, zero your scale, and then put 
>> the 10 grams on the capstan !!
>> Dont feel silly... many of us have stumbled on this one too.
>
>
> The only part of this which gets complicated is getting the front 
> weight on a back-weighted key. The value of FW as a measure of key 
> balance is that the front weight we read is how much heavier the front 
> half of the key than the back half. As long as that back half is 
> uniform, that net positive weight of the front has meaning. And it is 
> quite uniform, as David Stanwood quickly found out in his early 
> explorations, not only within keyboards but across many different 
> piano lengths.
>
> As soon as someone installs back leads, this predictable uniformity is 
> upset, which is why, when doing a action survey, back leads have to be 
> temporarily removed. But as David Love observed, this is not an issue 
> in reading key ratio.
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