[pianotech] FW: laminated ribs again

[Delwin D Fandrich]

  _____  

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of
piano workshop
Sent: January 28, 2009 11:53 AM
To: pianotech at ptg.org
Subject: [pianotech] FW: laminated ribs again
 

 

Hi List,

Some of you make and assemble the laminated ribs for a longer period of time,
compared to me.

Do you have any test between the regular ribs and the laminated ones regarding
flexibility, stiffness or other relevant differences?

Also, do you follow any criteria to scalloping the ribs in relation with length
and thickness?





 

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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