Curved Long Bridges

[Ron Nossaman]

>I just got finished realizing that any crown in a ribbed board is 
>incidental, and not required for support of the string load.

Then you realized incompletely. Crown along the ribs is a rather necessary 
part of current soundboard design.


>This meant that the underside of the bridge didn't need to be fitted to 
>match board curvature (crown) parallel to the board and bridge. What 
>remains is any extent to which the bridge may, in its path down the board, 
>cross the "continental divide" (as 'twere), and thus need to have its 
>bottom shaped to match this uphill/downhill contour. If this isn't done, I 
>could imagine that the flat-bottom (for lack of a shorter word) bridge 
>would would end up twisted in its cross section. Then the bridge would no 
>longer be plumb to the string plane, but rather to the whatever point in 
>the board's curvature you chose to measure it.

You're assessing all this from the pathological example of your bridge 
sample. Go through it again with the picture of the bridge I sent, and it 
will make more sense.


>Maybe I pulled this thinking out of the oven too soon, maybe I should put 
>it back in.

Yes, or rather, start over.

Ron N