[pianotech] scaling

[Larry Fisher RPT]

I have a Hardman 5 foot 7 grand that was destrung and the scaling notes were 
lost.  My job is to reconstruct the scale to fit the plate.  (I have the 
bass strings and the number of wound strings matches the number of hitch 
pins for the bass bridge) This sounds easy enough but there's about half of 
the tenor or middle section that is 3 hitch pins per two notes and the other 
half is 4 hitch pins per two notes.  That sounds easy enough to overcome as 
well however I'm trying to get a way point, a bench mark, an indicator on 
string size for a few notes in that area, specifically in the lower part of 
the scale (just above the bass strings).

Ok so I refer to some books, pull out some formulae and get garbage for 
results no matter what formula I use.  I even got my nerdy brother to help 
and I'm afraid that just generated more questions and no foward movement. 
(he's an engineer)

"The Calculating Technician" and "A Restringing Guide" are two books I've 
pulled formulas out of so far.

A440 note number A49, length of 15.75 inches and A220, note A37 length of 
29.375 inches are two notes I've used just to get the formula up and 
running.  I should have a string tension of somewhere in the neighborhood of 
160  (155 to 170 roughly) and I'm so far off using ANY formula that there's 
something amiss somewhere.

B27 is 43.675 inches
F33 is 34.75 inches
C40 is 24.675
F45 is 18.375
C52 is 13.25

>From there on up the scale is about the same as any other grand.  (using a 
four six or six four method)

If someone has a formula that WORKS I'd appreciate some help here.

Ready to scream in The Coov.

Lar


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090728/74db5550/attachment.htm>