David C. Stanwood wrote: > The solution that we use with Precision TouchDesign installations is to use > smooth front weights and center symmetrical key lead patterns around a > point half way in between the front of the key and the balance rail. We > keep the patterns as tightly spaced as possible. The patterns are always > close to center line of the front half of the key. We find that this > addresses the dynamic quality sufficiently enough using practical static > weight methods... > > Here is a picture of a "Tower Pattern" as we call it: > > http://www.stanwoodpiano.com/Pa100088web.jpg > Good point, well said David and I see your reasoning. Nice j-peg as well. > Theoretically I can imagine that the most ideal and dynamically smooth > displacement of weight added to the key for weighing off would be to use > bars of metal, attached to the bottom of the keys, of varied lengths as > needed to balance the key with their center point on the center point of > the key but what's the point of hair splitting? It's a good and necessary > mental exercise that's what... but impractical and unnecessary in the real > world. > > Thanks for the formula's John. > > David Stanwood David, I am sure you know that the center of your rods (or the center of any lead pattern) would not be the proper measuring point for measuring the moment of inertia. While you can use the center of gravity in static measurements it is not so simple for dynamic measurements. I concede that the way you have addressed the inertia problem is probable accurate enough it is not as rigorous as you method for static balancing. I am not one to do much hair splitting (that's how I keep a full head of hair) I have to say that your balance system does split hairs relatively speaking. So why not get just as .. err.. precise when working on the inertia of the action? You have made some good points but still there remains the question: How can we measure directly the inertia of the action or the inertia of any action part? Just as you have come up with solutions to measuring the static balance of an action I would like to see some way to measure the dynamic properties of the action. Until we have a way to do this we will not know if there is a benefit to calibrating the inertia of the action. Or how important calibrating the inertia of the action is compared to calibrating its static balance. BTU I really like your round slide rule for calculating balance components. It is smart as well as beautifully designed. Good work! John Hartman RPT John Hartman Pianos [link redacted at request of site owner - Jul 25, 2015] Rebuilding Steinway and Mason & Hamlin Grand Pianos Since 1979 Piano Technicians Journal Journal Illustrator/Contributing Editor [link redacted at request of site owner - Jul 25, 2015]
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