Del, I take it then that your ribs are horizontally crowned into the shape you desire. Do you find the stability to be any different between horizontally vs. vertically laminated ribs? I think we talked about this once but I'd like to firm it up in my mind. Greg Newell On 11 Jul 2002 at 23:37, Delwin D Fandrich wrote: > > > ----- Original Message ----- > From: Erwinspiano@AOL.COM > To: pianotech@ptg.org > Sent: July 11, 2002 11:01 PM > Subject: Re: Bridge design > > . Our own experience bears this out. We've been using laminated > Sitka spruce ribs for many years and our direct comparative tests > have not indicated that they are any stiffer than comparable solid > Sitka spruce ribs. They do have many characteristics we find to be > desirable, but greater stiffness is not one of them. Del > > > > > > Del > Then why go thru the trouble of laminating ribs except it's a > good use of otherwise unusable > spruce or the design characteristics are vastly superior. It's a > good deal more work > > Since no one asked the obvious question earlier there must be > some very desireable attributes > to laminated ribs to compel one to do this routinely. For me the > jury still's still out. > > So far all I can determine with my limited experience with Glue > Lam. ribs is that,when I've > done this I've laminated three or four pieces of quartered sitka > in my soundboard press. Instant 60ft crown glued in, but the > process is a bit messy. I thought that the ribs seem to be more > uniformly stiff though. > Also the rib is uniformly thick like old flat ribs only nicely > bent into an arch/arc negating the > cutting of the ribs radius unless a different one is desired. > > Laminated ribs aren't thicker in the middle than on the ends as are > crown/radius cut ribs. > Desirable or not? Dunno yet. > I didn't find the ones that I did too have any better tone than the > no laminated boards. I've also > Found that white spruce to be far stiffer and more uniformly stiff > than Sitka (which seems to vary greatly). Hmm another reason to > laminate. > Any secrets left. Don't feel obligated > . Dale Erwin > > > Consistency. Uniformity. Stability. And a pre-determined and > predictable crown radius -- we mold the various radii into the rib as > it is being laminated. > > Del > >
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