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At 11:24 AM -0500 21/2/04, David Skolnik wrote:
>Thanks for the photos. They are interesting, though not directly
>related to the Sohmer config.
Indeed. I've seen a couple of images of the Sohmer set up, but sure
would like to see a closer view - Ed?
>. . . Just curious how you got such good pictures
SLR with long focal length lens and close up bellows (an accessory
sleeve which allows for close up focusing) - Nikon 35 mm slide
scanner - Photoshop
In the case of the Stuart agraffe images,
http://overspianos.com.au/strtagr1.jpg
http://overspianos.com.au/strtagr2.jpg
I converted them to greyscale to reduce the image size for the web.
>Actually, one question. Is the silicon their addition or yours? Thanks
Most definitely theirs. We service the Stuart 290 at the Sydney
University Great Hall, but we're tuning and voicing only. We are
unlikely to be required for any rebuilding matters down-the-track
when the master himself is only 1.5 hours north of Sydney.
At 9:17 PM +0100 21/2/04, Jean-Jacques Granas wrote:
>. . . The setup visible on the second picture looks to me like one
>that would eliminate the stress excerted sideways upon the bridge
>that I alluded to in my previous post.
They both will, but the earlier Stuart agraffe shown in the first
image will also help to roll the bridges on the board. Mr Stuart
makes quite a thing of the elimination of side torque, claiming that
it is one of the reasons for the 'improvement' in the tone of his
instruments. I remain a skeptic on both counts.
>. . . To me, the bridge seems the more vulnerable as it is
>laminated and uncapped.
I doubt if his bridge will have structural problems due to the
laminations or the absence of a cap, since the agraffes aren't quite
as hard on the bridge as a conventional pinning set up, but the 24 mm
bridge height of the Stuart is probably too low. To my knowledge
there is only one other contemporary concert grand manufacturer who
uses 24 mm low bridges. Neither have inspired emulation.
>I just love the little string slot on picture No 2. Brilliant!!
The idea is potentially very good, but a wider slot would be better
to provide string clearance. There will be some who doubt that the
slot and string could be noisy with these agraffes since the agraffe
string segments lengths are so short. But I have experienced this
problem with conventional bridges where the spacing of the the bridge
pins was so close in the trichord section that the strings were
buzzing on the neigbouring unison pins. Unfortunately, it was a
factory made bridge cap which we installed during the course of a
partial rebuild. I had to inform the client that the problem was with
the bridge pin layout and that it was really beyond something we had
done. As a engineer and a keen amateur pianist he understood, but it
remains a disappointment for both of us.
While we're on the (interesting) topic of bridge agraffes, Ron N
posted an earlier example of a bridge agraffe which incorporated a
in-built solution to the noise problems under discussion above, and
looked economical to build. Here it is again for those of you who
missed it;
>Are such agraffes used on Stuart pianos up and down the scale, or
>just in the bass section?
The entire compass is bridge agraffed.
>What does the downbearing look like on those pianos?
I'm not sure. More than a rule would be required to ball-park it. So
far I haven't gotten around to making a device for measuring it.
Furthermore, the ribbing is very light (typical rib sections 20 mm
wide by 20 - 21 mm deep -19 of them on the concert piano) so that it
wouldn't stand for much in way of down bearing force.
> The tensions alone would clamp the string to the bridge very
>effectively on this setup.
Indeed, but I'm not sure that effective clamping of the string to the
bridge is all we should be striving for. I suspect that down bearing
might be required for the effective transmission of the lower
partials. Now I realise that in a number of posts from credible
members of this list, it has been claimed that down bearing is not
necessary for the production of satisfactory tone, but I remain
unconvinced at this stage.
Ron O.
--
OVERS PIANOS - SYDNEY
Grand Piano Manufacturers
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Web http://overspianos.com.au
mailto:info@overspianos.com.au
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