> From: jackhouweling at dccnet.com > Date: Mon, 26 Jul 2010 17:20:50 -0700 > > Here is the latest freak of nature I saw. Brand new Chinese piano with "stagger stagger pins". > > Regards, > Jack Houweling Hi Jack (et al), I agree that it is shoddy work. However, the intent, I believe, started out as a good one: to keep bichord pairs equal in speaking length so that they match in inharmonicity and tune together as acceptable unisons. I rotated your photo, and indicated green horizontal lines that connect each bichord pair (at least approximately - I wasn't too accurate with my mouse). If the bridge had been notched along these lines (more or less; I estimated the bridge rotation), then the notches would have been (at least close to) parallel to the upper termination, and the speaking lengths would have been the same for each pair. So, there was a valid reason for the staggerd pairs of bridge pins, but the lack of notching, unfortunately, torpedoed that ship long before it left port. Incidentally, I have assumed in pianos with staggered notching (like this one should have been) that the staggering at the waste end of the string (non-speaking part at the rear of a grand or bottom of an upright) serves to keep string friction across the bridge top equal, and also, in grands with rear duplex bars or plates, to equalize within each pair the downhill angle at which the string leaves the bridge, making rear downbearing more consistent and rear duplex lengths the same. If anyone can confirm or deny these rationales, or provide others, I would be interested to hear about it. Thanks, Joe DeFazio Pittsburgh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100727/ce75bc4a/attachment.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: BridgeRotated.jpg Type: image/jpg Size: 10544 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100727/ce75bc4a/attachment.jpg>
This PTG archive page provided courtesy of Moy Piano Service, LLC