The significant figure is not the breaking strain of the wire, but its elastic limit, also known as the yield point. In steel piano wire this is about 0.6 of the breaking point, and the string must be stretched under this limit. My understanding is that the wire used for harpsichords is originally piano wire which is annealed to make it more flexible. I wonder if this may be overdone. At the the Banff Center we had a Willard Martin that had a very high breakage rate, and we could find no explanation, other than the tensile strength of the wire was too low. Stephen Birkett, Associate professor and Director, Piano Design Lab at the University of Waterloo, Ontario Canada has been researching iron wire, as he contends this this would be a better solution than annealed steel. He has invited me to visit, but so far this has not been possible. By the way, using a thinner wire makes little or no difference if the tension is too high, as Ed noted. Ted Sambell ________________________________ From: Paul T Williams <pwilliams4 at unlnotes.unl.edu> To: Ed Sutton <ed440 at mindspring.com>; caut at ptg.org Sent: Tue, October 12, 2010 4:28:11 PM Subject: Re: [CAUT] Harpsichord popping strings Ed, This is a very interesting point about previous usage prior to my joining UNL. Yes, indeed, the harpsichord was used quite a bit more with the former organ professor. Of course, Richard had much more work to do on this instrument, while, since starting here in 2006, have had very little time with it, or it's general use, and our current organ prof started the same time as I. I don't think in 4 years, I've spent over 50 hours with it...just tuning and replacing strings and such. To Ron and others: I've never learned how to calculate string break tension numbers; Could you please explain? This will help me tremendously in this and other real piano issues! Thanks again, for all your continuing support! Paul From: "Ed Sutton" <ed440 at mindspring.com> To: <caut at ptg.org> Date: 10/12/2010 02:48 PM Subject: Re: [CAUT] Harpsichord popping strings ________________________________ That would be an empirical way to determine a reasonable break% for harpsichords in institutional circumstances. Or perhaps someone has already worked on this and can give a reasonable guideline. I am trying to point out what I feel is a significant problem. A fine harpsichord for private ownership and use may not be ideal for intitutional use. Tyre was a good builder, and I don't think he would have made an instrument with strings that constantly broke under normal conditions as he understood them. Many years ago I attended a school in Louisiana which had a fine Dowd instrument. As long as a teacher played and maintained it regularly, it did well. When the teacher retired and the instrument was left unused in the same office, it began to break strings spontaneously when the humidity changed. Other people have reported similar experiences on this list, such as with a Willard Martin harpsichord, another well-designed instrument. Unfortunately, replacing strings with stronger material may change the sound of the instrument significantly. The stringing scale and string material are important parts of the design of a historically informed reproduction. If the only real need is for a continuo instrument, something less wonderful may be a better choice. Ed S. ----- Original Message ----- From: "Ron Nossaman" <rnossaman at cox.net> To: <caut at ptg.org> Sent: Tuesday, October 12, 2010 3:16 PM Subject: Re: [CAUT] Harpsichord popping strings > On 10/12/2010 1:52 PM, Ed Sutton wrote: >> Ron is correct, if anyone knows what is a reasonable break% for a >> harpsichord, or more precisely, a harpsichord in institutional >> circumstances, which rarely provide adequate care for the more delicate >> instruments. > > The intent wasn't to start another thread speculating on what the true and > correct guessed break% should be in institutional situations, but rather > to find out what the numbers are in the real and actual strings that are > currently breaking, as opposed to the numbers in real and actual strings > that are not. > > Ron N -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/caut.php/attachments/20101012/9642c700/attachment.htm>
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