Killer Octave Question

[gordon stelter]

No! It makes no sense! I leave it to you to build a
bridge that is kerfed on the underside, bent to fit
the board and then filled with epoxy!
     Thump!

--- Farrell <mfarrel2@tampabay.rr.com> wrote:
> I've done some playin' and some tinkin'. And I've
> decided that there is a difference between a crowned
> bridge, but that the difference, in practical terms,
> is negligent.
> 
> If you cut a circle out of cardboard one foot in
> diameter, and then cut a circle out of the middle of
> that, let's say eight inches in diameter, you have a
> big flat donut. Set that donut on a basketball so
> that it sets like a topless hat. Now also realize
> that you need about a foot of tangent coming off the
> donut at some point (low tenor or long bridge). Now
> you can see the argument for a crowned bridge. Or
> perhaps not really just a crowned bridge, but a
> bridge that has a bottom bevel in the treble area
> and a crown in the lower tenor.
> 
> Now back to reality. Soundboards, even Fandrich
> soundboards, have a larger crown radius than a
> basketball, and a bridge is only 32 or 35 mm wide.
> So I do suppose that the ribbed soundboard panel and
> bridge itself will conform quite readily to the very
> slightly mis-matched straight bridge and curved
> soundboard panel. The tenor end will bend enough
> (what, maybe 1 mm) and the treble section of the
> bridge can have a top whose plane is not quite
> parallel to the plane of the bridge bottom/panel top
> interface. Bottom line: any difference is close to
> or wholly within common woodworking error and
> completely negated by the flexibility of the woods.
> 
> That make sense?
> 
> Terry Farrell
>   
> ----- Original Message ----- 
> From: "Ron Nossaman" <RNossaman@cox.net>
> To: "Pianotech" <pianotech@ptg.org>
> Sent: Sunday, April 13, 2003 12:02 AM
> Subject: Re: Killer Octave Question
> 
> 
> > 
> > >FWIW: I just cut a long bridge out of an old
> Mason & Hamlin and it is as 
> > >flat as a pancake. Not a speck of crown to be
> found.
> > >
> > >Terry Farrell
> > 
> > You can tell? How tragic. One of the points I try
> to illustrate in my 
> > bridge building class is the difficulty in
> determining whether or not the 
> > original bridge was crowned, and how important it
> is to the assembly. An 
> > old Knabe bridge, lying on a table and propped up
> in the middle with a 
> > pencil, shows a lovely crown from end to end. Pull
> the pencil out, and it's 
> > dead flat. That bridge will lay on a crowned
> soundboard and very nicely 
> > conform to the crown of the board.
> > 
> > Ron N
> > 
> > _______________________________________________
> > pianotech list info:
> https://www.moypiano.com/resources/#archives
> _______________________________________________
> pianotech list info:
https://www.moypiano.com/resources/#archives


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