This is fun !!! This is a suggestion I made
years ago, on this list, and was roundly "poo-pooed" (
as usual ) if I remember correctly.
So, then, who's refined this technique and put it
into practice, and where can I read about their
discoveries ??? And should I use sugar pine, spruce,
maple or what for the added lamination ? And what kind
of glue ?
( I was thinking epoxy would have minimal creep, but
then, if the rib and addition were dowelled together (
maybe with bamboo skewers ) the couldn't "skid" over
each other, at all.
Thump
P.S. This 57" Ivers and Pond upright has very wide
ribs, with nearly flat tops and a lot of room behind
the posts, so it's tempting !
--- Richard Brekne <ricb at pianostemmer.no> wrote:
>
> Rib extenders are simply additions to the height of
> the existing ribs.
> They can be made with some degree of machined crown
> so that when glued
> they exert an upwards force on the existing
> assembly. One can also put
> them in a high humidity hotbox and glue them on in a
> state of very high
> MC so as to attempt to take advantage of their
> shrinkage as they loose
> MC... kind of the reverse of gluing a dried panel on
> the board. That
> last came to me from Ron Overs recently. I suppose
> you could press the
> assembly upwards as well and glue on extenders match
> the surface of the
> existing ribs... also a way of increasing crown.
>
> The point with extenders as I understand it is that
> they increase
> existing rib height... which does a lot more for
> stiffness without
> adding as much mass as adding extra ribs will. Of
> course you have to
> have room to place them... and if you are dealing
> with very high ribs to
> begin with then perhaps this is not such a good
> idea. But for shallow
> and wide ribs that have lost their gumption....
> seems like a good idea.
>
> Cheers
> RicB
>
> "Rib Extenders "??? What's that ??? This one
> has wide, flat topped
> ribs,. so I thought I might laminate something (
> suggestions as per
> materials appreciated ) to their tops, if I'm
> not happy with the
> crown I get. I'll tell you all about this
> recrowning method when
> I'm done, and have more to report per results.
>
> Peace,
> Thump
>
>
>
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