String vibrations (was Re: Stuart)

Delwin D Fandrich pianobuilders@olynet.com
Mon, 22 Sep 2003 07:10:21 -0700


----- Original Message ----- 
From: "CalinTantareanu" <calin.tantareanu@mae.ro>
To: "Pianotech" <pianotech@ptg.org>
Sent: September 22, 2003 12:38 AM
Subject: Re: String vibrations (was Re: Stuart)


> Del,
>
> Do you have a picture of the device (bridge agraffe) developed at
Baldwin?
>
> Calin

No. Though I probably do have a drawing in some early version of the CAD
software I was using back then. Whether or not it can still be opened by
the new and improved version I'm using now is another issue.

Stuart's device uses what appears to be a ceramic rod insert for the
leading edge string bearing and a brass rod at the back. Ours were machined
of a solid brass block with the string bearing directly on the brass. They
were not nearly as pretty. Had we moved to production they would probably
have been made of a brass/iron powdered metal alloy. At least that is what
we were thinking of at the time. Not being one to pass up a good idea when
I see it, if I were to resurrect the idea today I'd sure want to look into
the ceramic rod idea.

Relative to those I saw on the Stuart piano in Sydney, ours were just a bit
longer -- long enough so we could put a small screw on either side of the
center post. Besides holding the thing down, these two screws aligned the
thing to the bridge -- they went into two pre-drilled holes in the bridge
surface.

Stuart uses some type of muting material just aft of the leading string
bearing, we did not. But, he is using the thing in a limited production
piano -- we were experimenting with them -- I expect he may have learned
something along the way.

Del



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