<html> <pre> Jim Coleman's Data > >Here are some examples of tests taken at the CGConn engineering labs while > >I was there. > > > >wire size yield point break point > > > >13 258 lbs 290 > >13.5 267 303 > >14 317 355 > >15 > >16 347 398 > >18 431 487 > > > > > >There can be as much as 10 to 20 pounds greater tension in the segment > >between the tuning pin and agraffe as there is in the speaking length > >while pulling pitch up. I take it to mean the yield point is the same as elasticity limit. Where the elasticity limit is that tension where "stretch" or elongation occurs. The string gets pulled so much that intead of returning to its original length, it stays "stretched". This happens well below the breaking point. There are theories that strings pulled beyond their elasticity limit,"no longer can be expected to function as music wire". (the other explanation for false beats) So two question, is yield point the same as elasticity limit? and how is/was yield point measured? Here are some historical records of string strength taken from Dolge. (wish I had a scanner) 1867 World's Exhibition, Paris Moritz Poehlmann's wire Nos. 13 14 15 16 17 18 broke at a strain of .............Lbs. 226 264 292 296 312 348 1876 World's Exhibition, Philidelphia Steinway & Sons' testing machine used. Moritz Poehlmann's wire Nos. 13 14 15 16 17 18 Lbs 265 287 320 331 342 386 1893 Chicago World's Fair Poehlmann's wire Nos 12.5 13 14.5 15 16 break point lbs 325 335 350 400 415 Jim Colman's tests Nos 13 13.5 14 15 16 18 break point lbs 290 303 355 398 487 This shows piano makers have had modern strength wire for 100 years. Richard Moody </pre></html>
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