Up and down weights

[Richard Moody]

----------
> From: David C. Stanwood <Stanwood@tiac.net>
> To: pianotech@ptg.org
> Subject: Re:  Renner "Turbo Wippens"
> Date: Monday, October 12, 1998 5:56 PM
> 
> 
> 
> 38 is a good "Normal" BW for modern pianos.



 
With dampers? Straight across the keyboard including those without?  Is
there a test for BW or is BW a "computed" figure?  Down weight = MINUMUM
weight to push a key down.  Up weight= the MAXIMUM weight a key can have
on it and still rise.  Why does it seem to me BW can be a RANGE of weights
inbetween and not just the difference? Or do I mis-understand the terms? 
I can understand a difference of DW and UW representing  friction,
especially if  the model is a frictionless see-saw. 
	I guess my question is if down weight is 50 and upweight is 35, why
couldn't any weight between 50 and 35 be a balance weight? Which to leads
me wonder why simply measuring the difference between DW and UW from one
key to another would not give an accurate indication of varation of
friction between the keys? And if one key varied too much, you better look
for too much friction or too little friction


Richard Moody