Measuring Counterbearing angles

[Jenneetah]

At 4:57 PM -0700 9/29/04, David Love wrote:
>What's a good method or tool for accurately measuring the counterbearing
>angle when reconfiguring this area.

Believe or not the sealing strip from a bag of Salteens or ground 
coffee. You know, the big bother to the twist tie. The pair of wires 
set 3/8" apart and embedded in soft plastic. It conforms nicely to 
any surface. I was even using it for a while to show me the capo 
bearing radius. (It got the job after passing the test of wrapping 
around the edge of a razor blade.) Press-apply, remove, trace the 
angle with aper and pencil, and measure.

Of course to get the three string planes (before front duplex, after, 
and after capo) you'll have to measure twice (at duplex and capo), 
but you'd have to with anything. Except of course for this solution 
which just came to mind: Cut a piece of card stock roughly resembling 
the side view of the string path, which you will press against the 
side of the string. This strip of card stock will have to be trimmed 
such that it can fit in the available space (ie, amount of space 
below the string in front of the duplex, the "beveled" jutting 
forward of the plate flange during the duplex length, and of course 
cutting out a generous amount to bypass both bearing bars.) Press, 
remove, apply protractor and measure.

The above methods assume that the strings are on the piano. Measuring 
the string path (which is what reading bearing angles is doing) 
without strings is another ball game.

BTW, once you've got these, it might be interesting to calculate the 
pressure of the string on the two bearing points.