Shopping for a Belly

[Ron Nossaman]

>So I wanted to find someone out here who was on the same track as Del and 
>Ron, rare birds that they may be.

If there are, I don't know who they might be.

The point I tried to make in that post to Terry, is that it isn't a remote 
control kind of thing with a simple set of applied parameters. It's a 
redesign. The rib set is designed to fit the string scale, bridge position 
(including the transition bridge and elimination of the bass cantilever 
that O would surely benefit from), proposed bearing schedule, and case 
shape - including the new cutoff bar and bracing that O would also surely 
benefit from. Crown radius is important, as is specific rib stiffness, as 
these are major determinants of load bearing capacity and acoustic 
response. The bearing schedule, and resultant rib dimensions, will be 
affected by the available back scale lengths. None of these things are 
arbitrary, or universally applicable as a checklist for any specific piano. 
That's the point. Your MC and crown requirements assume that the existing 
rib set, with added unspecified crown, and without the panel support gotten 
from drying the panel to 4%, will support string load, and do it for longer 
than the previous attempt. I don't know if that's the case or not.


>  The second (working E.M.C. during the process) would tell me what they 
> knew about where E.M.C. should fit between the fatal floor (where 
> extraction of moisture collapses cell walls), and the reasonable ceiling. 
> That reasonable ceiling is based on the range of R.H. the piano will 
> encountered once it's delivered, and should be set such that, during the 
> dry winter, board E.M.C. won't drop below the process E.M.C. (splitting 
> the board), and during the summer it won't raise high enough above 
> process E.M.C. to cause compression failure. (A 6% spread between process 
> E.M.C. and hot humid summer E.M.C. is what I was quoted in a conversation 
> yesterday.)

Depends on how much of the bearing load is being supported by panel 
expansion and how much by the ribs. Compression set is a long term 
deterioration as well as an immediate "failure" sort of thing. The previous 
board had been failing all along since installation.


>Certainly climate control is a necessary ingredient in this.

I would hope so.


>So, back to square one. I'm hoping that I don't have to ship the piano out 
>to Kansas or Washington to get a bard of this style, and thought that with 
>the right leading questions I could find someone up here doing board work 
>with the same approach. My two questions seem well designed, and the 
>follow-up questions would be based on how these first two were answered.

It depends on the degree of change you want. If you want what either of us 
do, you'll likely have to get either of us to do it. Something a step in 
the direction of what either of us does, and some insurance of better crown 
retention can be had with the addition of crown to the ribs as you said.

Later, off to a day of inharmonicity busting.

Ron N