Hey Marcel, I know how frustrating that can be. For starters, it will not implode unless the plate is weak, and the frame and pinblock are improperly fit. Examine the plate and make that determination first. Consider the plate mfg in this determination. Are they known for weak plates? ie: bechstein. next, good scale design as you already know accounts for 20% overpull before it reaches breakage. A simple rule of thumb is that a smaller diameter wire reaches pitch with less tension because it reaches pitch quicker than a thicker wire. be that as it may, be careful to take guesswork at string sizes. A pianos scale should reach designed pitch with even tension on every string. If this were not true, the speaking length could all be the same. (which is impossible.) A good safe laymans approach is to view the excel numbers as a "guide" rather than "finite". There are other variables in the design that may alter their numbers. Examine the speaking length of a similar size piano. I would measure every 7th string set beginning with c88. If they are within 1/8" of each other for the first two octaves, then reference the string diameters of the strung piano. If those numbers are close to the suggested scale of the gaebler, than your ok..... if the bridge in the highest octave allows for example 2-1/4" speaking length on c88, then you will be assured of high tension. Again, this is a generic example, but using some guidelines you should be able to come up with a good answer. Good luck, God bless, Mark Perry www.carvedpianoparts.com From: mcpianos at hotmail.com To: pianotech at ptg.org Date: Wed, 11 Nov 2009 13:07:03 -0500 Subject: [pianotech] scale design HI, I'm in a bind with a Gaebler piano that I took in for repair (pinblock strings etc.). When I run the numbers with my excel file, I get extremely high tension in the treble section and I'm worried about the breaking % that gets above 79%. Is that still workable. At this point I'm just scared and I didn't quote to do a bridge recap... Am I scared for nothing or could this beast implode on me? Thanks, Marcel Carey Sherbrooke, QC Tirez parti d’une offre Windows 7 exceptionnelle, et voyez comment il vous simplifie la vie. Explorez maintenant les offres Windows 7. _________________________________________________________________ Windows 7: Unclutter your desktop. http://go.microsoft.com/?linkid=9690331&ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_evergreen:112009 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20091111/a79f9ac0/attachment.htm>
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