Weighing off by balance weight

[David C. Stanwood]

Ed,

My hats off Jim Ellis as well for his original thought.  When I came up
with the Balance Weight system in 1990 I thought it was my original
thought... that is to say, I came up with the concept on my own without
prior knowledge of the formula.  So in that sense I enjoyed the sense of
original discovery.  However, it was soon pointed out to me that, while I
may have had a new method for balancing keys that accounts for friction,
Don Gault gets credit for the original formulas for weight and friction
which he published in the Journal 1969.  On the line of this discussion, I
remember vividly a conversation, years ago, I had with a PTG member (I
remember the face but not the name) who related to me that he used to work
with Keith Hardesty in LA and told me about a method that Keith used which
is the same as that described by Jim.  I don't want to diminish Jim's
discovery... just offer what I've heard in relation to it...  If anyone
knows more about Keith Hardesty it would be nice to learn more about this
interesting Tech...

David Stanwood


>   Dear List-       During our discussion of inertia in    piano actions a
>few months ago, Jim Ellis presented some of his thoughts on    the problem,
>including the suggestion that weighing off should be done    relative to a
>target balance weight.         Opportunity came in the form of a small   
>Knabe action in which just about every design decision was wrong.       To
>interpret Jim's idea, I made three    pairs of weights, representing
>varying amounts of friction with a 37.5 gram    balance weight, thus:      
>         The goal is to produce equal speeds of and down movement    for
>each pair, but faster as you compare the 25/50 weights with the 22.5/52.5  
> weights and then the 20/55 weights.               Observation with the
>weight pairs made the improvements of each change very    obvious.         
>                 and second-guessing was    minimal.       My hat's off to
>Jim for    this idea.       Ed Sutton