Cutting rib radii

[Farrell]

"...exactly the radii you want."

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.

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

Terry Farrell

----- Original Message ----- 
From: "Richard Brekne" <ricb at pianostemmer.no>
To: <pianotech at ptg.org>
Sent: Thursday, August 07, 2008 3:11 AM
Subject: Cutting rib radii


> Ribs are bendable enough that you can bend them to the exact radii you 
> want, clamp them in place and remove material from the concave side so as 
> to make that side flat. Unclamping will then leave that flattened convex 
> line at exactly the radii you want. You can put in some fairly complex 
> curves this way as well as long as your bends are not over too short a 
> span to hold adequately.
>
> Cheers
> RicB
>