Butt-Jointed Ribs

[Ron Nossaman]

>Del either posted recently, or I read it the other day in one of his 
>Journal articles (that I was reading for the umpteenth time) that some 
>piano manufacturer somewhere had apparently successfully finger jointed 
>short pieces of spruce together to make up a rib. Obviously a great use 
>for short pieces of expensive spruce.

Kawai. The ribs work fine, nearly as I can tell, and I'd like to see some 
in their more expensive models to make that obvious.


>If ribs are laminated, let's say with four to eight laminations, I wonder 
>what would be the effects of making all the rib laminations out of two 
>butt-jointed pieces, and spreading the butt joints evenly (or 
>preferentially) over the length of the rib.

It shouldn't be any different mechanically from a finger joint. Or if the 
butted sections were finger jointed, it would BE a staggered finger joint. 
Otherwise, I'd consider a 3:1 or 4:1 scarf. I wouldn't expect a problem 
with it, or any quantifiable difference in performance. If there was, I'd 
be surprised. For the bridge building class I've done, I made a stick about 
a meter long of laminated maple, using 8 or 9 2mm laminations. Each 
lamination has a butt joint, within about 20mm of the center of the stick. 
Bending the thing, it isn't obvious where the joints are even though they 
are very close to one another in the center of the stick.


Ron N