> > > > > I work in a very different environment than most on this list. Most of us > work in real time and space, while I work in cyberspace. I construct 3-D > computer models of every part in the piano action, assemble them in > cyberspace, and define dynamic motion studies. > > Frank Emerson > > Following this thread with great interest, it brings home loud and clear to me why I wanted to pursue thinking about action reconfiguration differently. The various traditional and even the more modern weight action geometry analysis protocols leave me feeling like I felt in that 1st day of 8th grade algebra: The teacher put a problem on the board. Of course that problem needed some sort of algebraic function to solve. However, not having the algebraic tools we sat there, at our desks, in long hand, taking guess after guess of what the solution might be, and then laboriously trying each solution out and hoping for the best. The inefficiency of that moment is still crystal clear 35 years later. The geometry of the existing actions that come into our shops is, in my opinion, largely unknowable, beyond some rather incomplete understanding of the whole picture. The number of variables are extreme, and all of them further complicated by wear, poor or horrendous original factory execution, tech accomodations,etc. While solutions can be had using various protocols and some degree of art, for my money, the whole picture requires both the ability to re-define the variables and re-design for optimization. Define design parameters around regulation specs which you target, take a small number of non-negotiable action cavity definitions(string height, strike line to straight line drawn between front of the case arms, height of cavity opening), define whip/shank dimensions and optimize the entire interactive geometry using math... ...in particular, optimize the geometry not only of the stack but optimize the levers of the key itself. With the exception of capstan placement, many of these action threads almost completely ignore the key levers. The optimization of the key lever, particularly the x,y of the balance point, as well as the sole's relation to the key bottom (ie proud/flush/shy), can buy a huge payback in terms of final weight of the key and action. Bruce Clark has approached this from just such a start-over approach. As well, he has defined a shop protocol to realize these design changes. The changes to the stack require skills that are already well developed in techs specializing in action work. The key takes more time and some very accurate woodworking skills(achievable). Presently, I am working in my shop to define procedures which can streamline the time consuming and somewhat tricky modifications to the key. Bruce's Key and Action software, is the math portion, and several of us are beta testing. Along with the software, the design phase is accomplished through knowledge of the geometrical assumptions, ability to fine-tune design (through skillset familiar to techs proficient in regulation), some autocad (not terribly hard) and real time modeling. The result, to say the least, is a global change in the way action re-work is approached. Final weigh off is per tech choice...for my money, plain old traditional weigh off is just fine. The final proof of the pudding, for me, is that the final weight of the key and action becomes a matter of choice rather than imposed by variable which were beyond my control. I believe Jude Revely is writing an upcoming journal article on this. Jim Ialeggio -- grandpianosolutions.com(under construction) Shirley, MA (978) 425-9026 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090316/0a224e0b/attachment-0001.html>
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