[pianotech] FW: laminated ribs again

[Delwin D Fandrich]

I have also seen laminated ribs on older pianos. So far, however, they have all
been quite different from those I use. I have seen vertically laminated ribs and
flat horizontally laminated ribs but never horizontally laminated ribs in which
the crown is molded in as the rib is laminated. But -- there may well be some
out there I have not yet encountered.

When I started experimenting with, and then using, laminated ribs some three
decades back there were no pianos using them on the market that I am aware of.
Nor are there now. Other than in a few rebuilding/remanufacturing shops.

ddf

| -----Original Message-----
| From: pianotech-bounces at ptg.org 
| [mailto:pianotech-bounces at ptg.org] On Behalf Of Euphonious Thumpe
| Sent: January 28, 2009 8:43 PM
| To: pianotech at ptg.org
| Subject: Re: [pianotech] FW: laminated ribs again
| 
| Not at all meaning to "pick on you", Del, but my 1899 Knabe 
| has laminated ribs. I doubt they're anywhere nearly as 
| scientifically designed as yours, but it's nice to know 
| someone also "came up" with this idea, "way back when".  Has 
| anyone here pursued laminating ribs on old soundboards "in 
| situ" to improve lost crown? ( With a thin strip added to the 
| spine of the old rib, in a compressed caul? ) I'm considering 
| experimenting with this method, on a really crummy old 
| upright, strings in place, with a  collapsed board. 
| 
| Euphonious Thumpe
| 
| 
| > I've probably been using laminated ribs longer than anyone 
| else in the 
| > business.
| > One of the reasons I became interested in laminated ribs was the 
| > inconsistency of ribs cut from solid stock. Both the mass and 
| > stiffness of conventional ribs varies widely depending on 
| the physical 
| > characteristics of the wood from which they are cut. By building up 
| > the ribs using thin strips of wood of varying grain characteristics 
| > both the mass and stiffness of the laminated ribs tends to be more 
| > predictable and consistent.
| > 
| >  
| > 
| > Back when I was experimenting with the process I did do 
| some testing 
| > to establish a basis on which I could calculate rib stiffness.
| > The primary impetus
| > for developing laminated rib technology was to be able to 
| predict the 
| > acoustical performance of a rib-crowned soundboard system 
| so I needed 
| > to know how they would react under load. I would suggest anyone 
| > switching to laminated ribs do the same. I've always 
| thought it a good 
| > idea to have a thorough personal understanding of the systems and 
| > materials with which I work.
| > 
| >  
| > 
| > Yes, I do follow a criteria for scalloping ribs. The description of 
| > what I do and the explanation of why I do it is rather more 
| involved 
| > than I care to go into on this list but it is something I cover in 
| > several of my all-day seminars.
| > Others probably do as well. You might check the line up of classes 
| > being offered at the Annual PTG Convention this year. I don't know 
| > just what is being offered but there might well be 
| something on this 
| > topic.
| > 
| >  
| > 
| > ddf
| 
| 
|       
| 
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