Bending rims... Jim B. (long)

[Brian Trout]

Hi Jim,

Sorry for my earlier confusion.  My mind was off on a tangent only known to
the faint and distant imagination.  I wasn't really thinking along the lines
you were, but had a memory in my head of someone, wwwaaaaayyyyyy back in
maybe the third thread back or so from this one, who said something about
using thick, maybe 1/4" laminations to make a piano rim.  On the occasions
I've tried to bend wood in curves as tight as a piano rim and that thick,
most of the time, they end up breaking someplace.  So I was thinking about
how one would accomplish using thicker laminations and was thinking about my
little soundboard project strip of wood thingy, and like I said, my thoughts
were way out in left field...  Again, sorry for any confusion.

Thanks for sending along the website.  There were a couple of things that
jumped off the page and threw little cyber rocks at me, egging me on to
respond.  :-)

1)  quoted from S&S webpage:  ..."The stacked layers are then glued into a
single form of wood by bending on the rim-bending press, a giant
piano-shaped vise."...  It wasn't apparent from the picture exactly what was
there, equipment wise.  But it sounds like we all might have really been
pretty close to reality all along.  A press, a vice, a series of clamps...
kind of depends upon how you're looking at it all.

2)  again a quote:  ..." The soundboard is pressed into the shape of a dome,
allowing it to withstand the combined downward force of 1,000 pounds from
over 200 strings."...   I thought I heard somewhere, that the engineering of
a soundboard is such that the 'arc', or 'dome shape' is not really a
significant factor in supporting the weight of those 200 or so strings.
Anyone care to comment on this one?  (Probably a pretty technical question,
but it came to mind when I read that statement above.)

3)  another quote:  ..."Before a soundboard can be placed into a piano case,
the bridge must be notched for the strings that will pass over it..."
Huh???  I had no idea they did it this way.  Or do they?  Actually, this is
something I've thought of bringing up on the list a couple of times, but
didn't have the ambition as of yet to put together an intelligent query.
But since we're here, ... how do most people who are putting in boards
progress through board and bridges out of the piano to board and bridges
glued in and notched?  I've done it several different ways.  I've built the
complete soundboard and bridge assembly before board glue in.  I've built
the bridges with tall caps, glued it all in, and then completed the bridges.
I've built the complete soundboard and bridge assembly excluding the
notching and pinning, and then glued it in. (And one or more variations I
won't go into...)  I've seen a number of variations, but don't know if any
one of them is actually any more 'correct', or 'better' than any other.  I
know it's a new topic, but I'd really be interested in what other people are
doing.??

4) yet another quote: ..."This network of bracing <belly bracing> helps
support the 340 pound cast iron plate."...  I find it fascinating that they
would mention 340 pounds of a cast iron plate and not mention the 10 or 15
tons of force exerted by all of those 200 or so strings.

Please don't read into this more than is intended.  I think it's a pretty
neat website that S&S put up.  And granted, too many facts and figures could
easily confuse many customers that don't have much knowledge of how a piano
is designed and constructed.  I understand that.

But amongst us tech types, there's some meat for discussion if anyone feels
like it.  :-)

Seriously, though, I am interested in the soundboard / bridge / glue in
assembly process that you're using and why you think it's the way to go if
you have time.  Perhaps a new thread might be in order??  :-)

Best wishes,

Brian Trout
Quarryville, PA
btrout@desupernet.net

----- Original Message -----
From: <JIMRPT@AOL.COM>

> Brian;
>   Through the magic of cyber space and courtesy of S&S I invite you to go
to
> the following web site for pictorial representation of a portion of the
rim
> bending process. :-)
> http://www.steinway.com/html/tour/tour.html