Simpler is better -- I like it! Is this significantly different from using your existing tool, Dale, where you just measure the first part of key travel and hammer rise? Does this average out the "arc" effects? --Cy-- Cy Shuster, RPT Albuquerque, NM www.shusterpiano.com www.facebook.com/shusterpiano On Sep 22, 2012, at 5:57 PM, Dale Erwin <erwinspiano at aol.com> wrote: > From: Jim Ialeggio <jim at grandpianosolutions.com> > > > Ron said: > > <It always annoyed me that the cumulative leverage of the presumed > moment arms matched so poorly with Dale's 6mm in/out direct measurement. > Something's wrong, and I'll take direct first. > > Jim wrote > My take...the position of half stroke should be determined by 1st > determining the full arc the hammer would travel, driven by the key at > its full dip, with the hammer unimpeded by the letoff button. Full > hammer travel in this scenario is of course more than blow(-)letoff, > but it exceeds blow as well. > Jim. > I like the way you think > Take the let-off button off and toss out the drop screw too. Now nothing is in the way to impede hammer rrise. Now set a very accurate 10 mm key dip, (however one does that) , then set a modest weight on the key to depress it fully, then simply measure the total hammers rise. Likely it will be 55 mm to 65mm. Divide by 10 equals a totally accurate direct measurement figure for action ratio. > Dale > Dale Erwin R.P.T. > Erwin's Piano Restoration Inc. > > > > > Jim Ialeggio > > -- > Jim Ialeggio > jim at grandpianosolutions.com > 978 425-9026 > Shirley Center, MA > -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://www.moypiano.com/ptg/pianotech.php/attachments/20120922/1c24b76f/attachment.htm>
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