[CAUT] Touchweight question

[David C. Stanwood]

Jim,

Is this piano made in Denmark..?  Sounds more 
like something a certain maker in Korea might 
have done back then.   Disengage a few springs, 
remeasure U/D then calculate the unsprung BW. 
Compare this to the BW with the spring on and the 
difference will tell you how hard the spring is 
working.   9g - 11g is a conservative value and 
will just support the weight of the wippen with 
the stack on the bench with the hammers flipped 
up.   17g would be an absolute limit not to be 
exceeded without danger of creating a "Bouncy 
Key" effect.


Support Springs aren't meant to fix a mismatch of 
hammer weight and ratio that results in too much 
lead in the key but rather a way of reducing lead 
in an action that is already working ok thereby 
making it a little lighter and faster on the 
upstroke....

If you action balances nicely after removing the 
back lead, disengaging the spring, and weighting 
the keys normally with the lead weights in the 
front then I would say Cut'em off!

David Stanwood



>All,
>
>I have an action (Hornung and Moller 1972) that 
>has one or two leads in the very back of the key 
>and no lead in the front. It has wippen helper 
>springs. DW is around 65 - 70 and UW is around 
> 36 - 40 or so. (Friction seems to be ok, but BW 
>is 50 - 55!!)
>
>I don't know why the springs were adjusted for 
>this weight, and I can adjust the springs to 
>achieve a good weight (50-20 or so) but my 
>question is a very basic one; Why would you use 
>springs instead of leads to touchweight the 
>action? What does this do to the MOI? Or, at the 
>very least what is the difference in feel 
>between a "spring" vs. "lead" touchweighted 
>action? And, why do one over the other?
>
>Fred, Ric, enlighten me!
>
>Jim Busby
>
>P.s. I experimented and put weights in about 8 
>keys and a normal leading pattern makes it 
>workŠnormal.
>