Dean, Think for a moment about the assumptions behind your statement. Do you assume the key material is homogeneous and isotropic? Ever see a key with 3 or 4 closely spaced 1/2 inch leads with cracks in the wood connecting some or all of the lead holes? Text book formulae are one thing, the real world is another. At the midpoint of a 1/2" hole in a 1" tall key, the stiffness is reduced by approx. 12%. Is this negligible, or can a sensitive pianist feel the difference? What about 2 holes, or 3 or 4? Worth testing on actual components, I say. Mike > [Original Message] > From: Dean May <deanmay at pianorebuilders.com> > To: Pianotech List <pianotech at ptg.org> > Date: 7/13/2006 9:53:51 AM > Subject: RE: Inertia, was "Grand Touch" > > The stress is all carried by the upper and lower fibers of the wood. Holes > in the middle have negligible effect. Think I-beam. All the stress is > carried by the upper and lower webs. You don't want to drill holes in them. > You can, however, drill through the connecting center web with no loss of > strength. > > Dean > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf > Of Michael Spalding > Sent: Thursday, July 13, 2006 9:31 AM > To: Pianotech List > Subject: Re: Inertia, was "Grand Touch" > > Jude, > > I think it's great thatyou will be testing this experimentally. One factor > you might want to look at is how the lead holes in the keystick affect its > flexibility. It seems to me that a keystick with several large led holes > close to the balance pin would flex more on a hard blow than one with fewer > or smaller holes further away from the balance pin. Looking forward to > hearing and discussing y our results. > \ > Mike > > > > [Original Message] > > From: Absolute Piano <absolutepiano at comcast.net> > > To: Pianotech List <pianotech at ptg.org> > > Date: 7/12/2006 9:02:37 PM > > Subject: Re: Inertia, was "Grand Touch" > > > > Thanks Vladan and all for all the info. > > > > There is a lot to chew on. My interest is in the practical application. > Why > > is it that two keys with the same balance weight and the same front > weight > > but leads arranged differently seem to me to feel the same? > > > > I ask because I had a customer that asked me to place all the leads > closer > > to the front and to use less leads after I had already set up the FW to > my > > specification in a new keyboard using a tower pattern nice and close to > the > > balance rail. I went through all the trouble but as far as I or anyone > else > > could tell the action felt the same. > > > > I'm in the process of building several action models to test the science > as > > I am slowly digesting it so you are all being quite helpful. > Unfortunately > > with reality hanging over me it may take awhile to report back any > results. > > > > Best, > > > > Jude Reveley, RPT > > Absolute Piano Restoration, LLC > > Boston, Massachusetts > > > > > >
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