[pianotech] Thoughts on Bearing Angles

Jude Reveley/Absolute Piano juderev at verizon.net
Fri Nov 7 08:10:48 PST 2008


List,

There is the well known diagram for downbearing that is often referred to in classes and discussions and is often cited as the geometric basis for calculating downbearing force. See page 37 in the Nov. 1995 issue of the journal as an example.  

 Using the following model:

Overall Length=100mm; Speaking Length=60mm; Backscale=40mm; Offset from staight plain=10mm

According to my calculations this would yield a bearing angle of 23.5 degrees with 9.5 at the front and 14 at the back. What I don't like is that in this traditional model, the length between the front and rear bridge pins is not accounted for but would certainly increase our rear and thus composite bearing angle. This seems somewhat significant since we base our calculation of the force on the bridge using this angle.

Am I missing something? Thoughts? Comments?

Cheers, 

Jude Reveley, RPT
Absolute Piano Restoration, LLC
Lowell, Massachusetts
(978) 323-4545
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://ptg.org/pipermail/pianotech_ptg.org/attachments/20081107/54bbcdd3/attachment.html 


More information about the pianotech mailing list

This PTG archive page provided courtesy of Moy Piano Service, LLC