on rib notching

[Ron Nossaman]

> Would anyone care to share their technique for locating and notching rib 
> ends into the inner rim?

I make a Masonite pattern, and rout the mortises - an idea 
stolen from Del Fandrich. I don't know if he originated it, 
but the mortises found in Baldwins look similar.


> My first piano I used two sided tape on the rib ends and set the board 
> in - the tape stuck to the inner rim and I used this to cut the notch.

I tape the ribs in the mortises with locater pins in the rib 
ends, then drop the panel in so the pins mark it for later 
assembly outside the piano.


> This was not as accurate as I would have liked.
> Some of the other problems were the shape of the rib end - being tapered 
> presented some difficulty with this notching - trying to match the taper 
> was not easy. On the second piano the rib ends are flat.
> Also the depth of the notch - should the depth of notch exactly match 
> rib end hight? Be slightly deeper?

I make the mortises both deeper and wider than the rib ends. 
There's no mechanical or acoustic reason to fit the ribs to 
the mortise.


> How thick or thin should the rib end be? Thinner is better in my mind. 

I cut mine about 4.5mm.


> Is there a limit on how thin?

They don't even have to be mortised into the rim at all, 
except there may be a tendency for the panel to crack on the 
bent side where the grain runs tangent to the inside curve.

Ron N