NY Steinway Ribs and MC

[Richard Brekne]

Hi Terry...

Sounds like you pretty much have the gist of it as I suspected.  As to 
the radii of the cauls... yes we (I in any case)  don't know the radii 
along each rib, and yes you don't necessarily need to dry to 4 % to get 
the same crown with 5 % dry down if you compensate with a caul with an 
appropriately small caul.

All that said... one has to assume that whatever the rest of their 
procedure is... it is pretty much the same as it always has been... so 
the 4% vs 5.5% discrepancy becomes quite significant. And in anycase... 
its kinda nice to once an for all get at least this much straight on 
this list as to dry down percentages at NY S&S.

Cheers
RicB


    I don't know what the exact implications would be with let's say panel
    ribbing done at 5.5% vs 4%. Obviously, with everything else being
    equal, the
    4% would develop more crown. But I've never built such a board. I do
    know
    that ribbing done in the range of 6.0% to 6.5 % doesn't develop much
    compression crown at 50% RH room conditions. I really don't know,
    but based
    on my very limited experience with compression crowning, I should
    think that
    ribbing done at 5.5% wouldn't produce enough crown for a compression
    crowned
    board - but then again, we don't know the radius (radii) of the
    cauls used
    when pressing - do we? You don't have to dry a panel down at all to
    produce
    a compression crowned soundboard if you press the straight ribs and
    panel
    into a small radius enough caul.

    Dunno.

    Terry Farrell

    ----- Original Message -----
     > Yes... that was the only real difference.  5.5 % versus 3.8%-4.5%
     > depending on the season.  As to the significance I attach to that
     > difference, I dont think I need tell you about any of the
    implications
     > there :) Thats quite a large difference if these are glue up stats.
     >
     > RicB