> The stability after restringing has other issues including the > straightening of the wire at the terminations, the tightening of the > coils, loops and beckets, etc.. This is not really an issue on a > piano that has already achieved that type of stability. I agree with you generally, but in the case of a large pitch raise (or any pitch raise - but certainly a large one), wouldn't some of the same be true? I'm referring to the front scale segment of string mostly - if you turn the tuning pin 1/16th of a turn, the string would move about 0.05 inches through the aggraffe (or capo) - and so would the bend in the string that formed while it was sitting in the aggraffe (or capo). Wouldn't that affect the pitch stability of that note as that small kink in the string straightened out over time? FWIW, I know Ron N will be very unimpressed with me for not calculating the change in length of the string as it goes from forming a small triangle to a straight segment and the associated change in pitch. My only excuse at this time is that it is 5:30 AM and I am working on my first cup of coffee. That's my excuse...... Terry Farrell On Aug 28, 2009, at 11:27 PM, David Love wrote: > What else do you think accounts? Soundboard compression? When a > string breaks and the entire section goes out of tune is it the loss > of a few pounds downward pressure on the bridge? If so, then simply > pressing down on the bridge should put the piano noticeably out of > tune. But it doesn’t. Additionally, when you destring the bass on > a piano where the bearing on the bass bridge is pretty much zero, > why does the tenor change so much in pitch? On the other side, a > single string breaking makes a change of over 300 lbs of tension on > the plate. The removal of the bass strings results in a net change > of 7000 -8000 lbs. I would assert that it is primarily (if not > exclusively) the change in the way the plate flexes that is > responsible for the change in pitch. > > The stability after restringing has other issues including the > straightening of the wire at the terminations, the tightening of the > coils, loops and beckets, etc.. This is not really an issue on a > piano that has already achieved that type of stability. The net > loss the comes about during a pitch raise is due primarily to > progressively added contractual tension to the plate. Other factors > that affect stability are the ability for the technician to > stabilize the various string segments as Ron outlined in a previous > post, plus getting to a reasonable starting point from which to > start the fine tuning process. > > David Love > www.davidlovepianos.com > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090829/0a445fe3/attachment.htm>
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