Variable overpull percentage (was: Finishing where you started)

[DGPEAKE@AOL.COM]

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In a message dated 12/1/00 6:50:36 AM Pacific Standard Time, 
michel_lachance@hotmail.com writes:



> No offense meant Dave and I thank you for straighten things up. I have owed 
> a SAT II and I know that the overpull percentage is fixed for that machine 
> (20% throughout or so).  If it is different for the SAT III, I beg you to 
> update my knowledtge on that respect.
> 
> For example, if both strings each side of the tenor break are 10 cents 
> flat, 
> RCT will raise the wound string by 12% over target pitch, and the lowest 
> plain wire string by 32% over target pitch, because practice tells us that 
> you need different overpull on those strings for an optimal pitch 
> correction.  That's why you have to tell RCT where the lowest plain wire 
> note is before you start tuning.  The overpull percentage varies throuhout 
> the keyboard (as well as the pitch offsets...) depending of the section of 
> the piano, according to statistics made on actual experiments on pitch 
> raises.  And you even have the option to change the overpull percentage 
> chart if you find that a particular piano reacts differently to an overpull.
> 
> So, for the sake of my own education, I would be grateful you tell me what 
> the variable overpull percentages are on a SAT III and how you tell the 
> machine where the lowest plain wire note is.
> 
> Regards,
> 
> Michel Lachance, RPT
> 
> 



I believe the overpull is 25% of the 2nd partial. Someone please correct me 
if I am wrong. (Jim, please pitch in). The SAT 3 is the same. I usually 
measure the lowest note of the plain wire, offset for pitch raise, and 
re-measure every octave or so.  I have no problems with doing a pitch raise 
using this method.  

Dave Peake, RPT
Portland Chapter
Oregon City, OR
www.davespianoworks.locality.com

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