Unusual rib structure?

[Farrell]

Del wrote:

"I prefer to terminate the ribs about 10 mm inside the inner rim for at least the half of the rib set."

Why 10 mm gap? What is your preference for the other half? - rib goes right up to rim? - rib overlaps rim? Why? Is it OK to have all ribs terminate without overlapping rim?

Terry Farrell
  
----- Original Message ----- 
From: "Delwin D Fandrich" <pianobuilders@olynet.com>
To: "Pianotech" <pianotech@ptg.org>
Sent: Friday, May 09, 2003 2:59 AM
Subject: Re: Unusual rib structure?


> 
> ----- Original Message -----
> From: "Greg Newell" <gnewell@ameritech.net>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: May 08, 2003 9:20 PM
> Subject: Re: Unusual rib structure?
> 
> 
> Del,
>          Do I take this to mean that there is no sudden taper 4-6" from the
> end of each rib? How thin is the gradual taper you speak of by the time it
> reaches the end? Do you bring the rib all the way into the rim or does it
> stop before the rim? Or do you still use the cutouts but leave a gap for
> free movement?
> 
> ------------------------------
> That is correct. There is no sudden taper. We do generally inset the ribs
> to notches in the inner rim (or bellyrail or cutoff bar) but only because
> it's easier to align for gluing that way. We make the end thin enough so
> that it doesn't really contribute all that much stiffness to the assembly.
> The end of the rib usually ends up about 4 mm thick where (and if) the rib
> overlaps the inner rim. On a production piano (where permanent jigs and
> fixtures would be used for alignment) I prefer to terminate the ribs about
> 10 mm inside the inner rim for at least the half of the rib set.
> 
> Del
> 
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