[CAUT] lighter touchweight

[Richard Brekne]

Hi Chris

Grin... dont really see what you are apologizing for, but let go.  Your 
posts have been thought provoking and well thought out seems to me.  
I've heard about the class you refer to and hope to run into this one on 
one of my infrequent visits stateside... HEY !... perhaps we can get you 
two to do the Nordic ?  :)

I still dont really see clearly how we are going to see a significant 
reduction in friction at the capstan/knuckle interface if all one is 
doing is removing a couple grams of weight there... much less if all one 
is doing is keeping the existing weight on the capstan but changing how 
much each of the two top action components individually contributes to 
that weight.

Even up at the top where the weight on the capstan can easily get as low 
as 70 grams... a subtraction of a couple grams of whippen weight only 
reduces the total weight at the capstan by just under 3 %.  And in the 
bass the total weight reduction would only be about 1 %.

I can certainly imagine how dropping the weight at the capstan by the 
total amount of whippen radius weight (using assist springs) might 
significantly affect friction there, but then you are reducing weight at 
the capstan by significantly more in that case.  About 25 percent in the 
above example... and say around 10 % in the lower bass.  Still... seems 
to me the bulk of friction in the action is to be found elsewhere.

In your looking into all this, have you and Don tried simply removing 
the hammer all together and attach comparable weight to the jack top to 
see what friction change there is in a <<with knuckle/jack friction and 
without>> scenario ?

Cheers
RicB


    I apologize Ric. To do this more"scientifically" you should of
    course remove
    lead from the key before/after hooking up the spring or after removing
    weight from the wip in order to maintain a constant BW. This is
    something
    Bob M and I discovered in our class recently in Oklahoma. We now use
    models
    to teach these principles, made by the Florida State piano
    technology grad
    program, with exchangable shanks having 15, 16 & 17 (10) mm knuckles
    (constant StrikeWeight), movable captstan boats, asssist springs, easily
    removable and replaceable leading, and we also introduce the cut
    punching
    and balance rail shimming techniques. Used to be hard to get these
    things
    across but thanks to the models we have arrived at a real method for
    teaching these concepts. And we are discovering additional benefits like
    "wow where did that additional friction reduction come from?"

    I agree with you, it must be a slightly higher Ratio than we would
    like for
    a happy marriage with the SW, but it appears nothing is to be done
    on this
    account. It has, however,  provoked some interesting discussion.

    See ya on the web,
    Chris Solliday