Cutting rib radii

[Ron Nossaman]

Farrell wrote:

> I think "radii" implies a circle or an arc thereof. If you apply 
> pressure to the mid-point of a board (or rib), the end portions will be 
> near straight and the center area will have the most curve. Yes, you can 
> produce the target "crown" measurement in the middle, but the shape of 
> the curve will not be an arc.

No, it won't, and I haven't been able to find any source that 
names that curve. It's not a parabola, and not a catenary, 
though the middle section of the curve is similar to either. 
Nearest I can determine, it seems to most closely be a sine curve.


> I guess then, the question might be: what shape rib is optimal?
> 
> Terry Farrell

Or if there's any detectable functional difference at all.
Ron N