<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF" style="MARGIN: 4px 4px 1px; FONT: 10pt Tahoma">   "Garret E. Traylor" wrote: <blockquote TYPE=CITE> This sounds like we could keep some graduate students very busy....personally I don't know anything about physics or mathematics.  But, surely some time/motion study based from this improved filming technology could reveal some very interesting data. "INERTIA relating to Piano Action Geometry: The Qualitative and Quantitative analysis of Non-Rigid components."Garret</blockquote> Stephen Birkett is working out something along these lines. Myself I am not so sure we need to get all that deep into the math/physics side of this... We do need to be aware of the affects of various weight / ratio configurations on any given degree of action compliance, and Del is right... that is not being taken into consideration by many now. When Stanwood puts a set of monster hammers on an action, and drops the ratio down to 5.0 or lower.. (I think his personal record is a 4.8 BWRatio) he doesnt worry about how much that actions felt compresses, how stiff the keys are... how much flex there is in the shank... etc etc. Nor does he do so for a 6.0 BWRatio with top medium hammers. He just balances things out according to his predetermined specs dictated by the Balance Equation. Yet it seems clear that the net compliance of any action is going to change for various configurations, and that definatly affects how the action feels, how it delivers its punch to the strings, and utlimatly how the voice of the instrument sounds.  So... while Static Balance can provide us with exactly a static balanced action.... it's less then << all we can easily do >> without some method of putting this into a compliance perspective. More or less the same kind of argumentation can be said about inertia. Heck... seems to me that we dont really consider whats happening with the employment of assist mechanisms conciously enough.   Cheers RicB   Delwin D Fandrich wrote: <blockquote dir=ltr style="MARGIN-RIGHT: 0px"> <blockquote TYPE="CITE"> <blockquote dir=ltr style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"> The bending spaghetti is the hammer shank with the hammer trying to hold on. And then there is even more maccaroni if you start with the flexing key. At the time between when the key is hit and the time the hammer finally hits the string I have already eaten part of the salad.</blockquote> <div dir=ltr>Hans Sander</div> <div dir=ltr> </div> <div dir=ltr>And yet we insist on discussing action geometry as if the various components were all infinitely rigid and had zero inertia.</div> <div dir=ltr> </div> <div dir=ltr>Del</div> </blockquote> Its a good baseline... but I agree... not much good in the end left to itself. RicB</blockquote> -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>   </body> </html>