<HTML> <HEAD> <TITLE>Re: [CAUT]  String stiffness questions</TITLE> </HEAD> <BODY> Hey, Alan & Ric, I believe Ric is asking about the inharmonicity constant.  I don’t know if that is the name used by engineers, but that’s what I have heard it called.  It relates length, diameter, and tension to predict the inharmonicity of a particular string/note.  PScale used it to generate an inharmonicity number for each note, and ETDs use it to build their stretch curves.  I have only seen one value referring to music wire in general, and I have wondered whether it might be different for Mapes vs Roslau.  I would certainly expect Pure Sound to be different.  I can’t lay my hands on a precise value, though.  Ron? Del? I’m getting in over my head here!  Bail me out! Regards, Ken Z. On 1/8/07 3:06 PM, "RicB" <ricb@pianostemmer.no> wrote: <BLOCKQUOTE>Thanks Alan... I was beginning to think I wasnt going to get any response on this at all.  No, its not the Young modulus I'm after.  I just need to know how to find this constant <<K>> which keeps coming up in formulas about inharmonicity and string stiffness. I also need to know if it changes along with the type of string material used. Specifically... in both Nossamans and Overs spreadsheets for scaling there is a formula for figuring out string stiffness in which a constant is used... and I have no idea where this constant comes from or what its actual meaning is... and hence have no idea if it remains the same for Pure Sound wire as compared to Rosslau for example. On the side.... I also am working on using the scale tensions that result from any given design to determine a basic downbearing picture for given string offsets and building that into the spreadsheet.  I already have that math in place.... so  the addition of one more specs column (for string offsets) and a couple calculation columns will yield downbearing in Kg for each unison... and a graph that shows how the scales downbearing looks over the entire soundboard.... Thought that might be handy :) Cheers, and thanks for reminding me of the Roberts source... I dont have his book... but There are those articles in the journal. RicB <BLOCKQUOTE> Hey Ric,   Are you referring to Young's Modulus (Y)? Have you checked out The Calculating Technician by Dave Roberts? I think there is info in his book that might be useful.   Alan     -- Alan McCoy, RPT Eastern Washington University amccoy at mail.ewu.edu 509-359-4627 </BLOCKQUOTE> </BLOCKQUOTE> -- Ken Zahringer, RPT Piano Technician MU School of Music 297 Fine Arts 882-1202 cell 489-7529 </BODY> </HTML>