Agraffes

[Farrell]

Thanks Ron for the details. I have another questions for you or anyone with
an opinion. I believe Bosendorfer uses a brass agraffe but drills a hole
(presumably horizontal, perpendicular to the string direction, and at the
top of the hole or so) through the agraffe and inserts a stainless steel
rod. The string then rides on the rod, thus eliminating any brass
termination problems. As long as a rod of preferred material and shape is
used (similar perhaps to what one might desire for the capo surface), it
seems as if this would be a better solution, and would be an easy option to
implement.

Or is this a newbie question from left field?  ;-)

Terry Farrell
Piano Tuning & Service
Tampa, Florida
mfarrel2@tampabay.rr.com

----- Original Message -----
From: "Overs Pianos" <sec@overspianos.com.au>
To: <pianotech@ptg.org>
Sent: Saturday, April 14, 2001 2:33 AM
Subject: Re: Agraffes


> Terry and list,
>
> Terry wrote;
>
> >Thank you very much Ron for sharing your tool shape with us. . . On
> >the far right side of your drawing is the end profile of the tool. .
> >. . I suspect it is the cutting edge,
>
> Yes it is. It's not a very good CAD drawing since it was one of my
> earlier examples from about seven years ago.
>
> >- is it more-or-less like a countersinking tool? (I'm sure a grinder
> >dude would know exactly what it is).
>
> My cutter grinding dude uses center drills, then grinds the ends to
> the profile specified in the drawing.
>
> >Also, I do not understand exactly what a donut shape for the agraffe
> >center is. .  Do you go for a continuous arc through the agraffe
> >center
>
> Yes, we look for a continuous but small radius arc through the string
> hole. I have experimented with both a sharper inner hole (which you
> get by using an ordinary tapered cutter from each side) and the later
> version with the small rounded profile. I don't think brass agraffes
> are very good at the best of times, but the donut shape (the rounded
> profile string hole) seems to be marginally more serviceable. You
> will also notice that we run the arc around sufficiently to produce a
> 0.005" (0.125 mm) clearance with the 20 degree countersink portion of
> the hole. Again this seems to allow for a slight tonal improvement.
>
> >  I have a 100-year-old Bechstein waiting for a rebuild in my shop
> >that has 88 of those little bad boys - they have been staring at me
> >for more than a year now and I have felt VERY intimidated (although
> >I have tried not to show it). Thanks big time!
>
> It can be intimidating doing some of these rebuilding operations for
> the first time. But it's a great feeling to get through each obstacle
> along the way.
>
> Regards,
>
> Ron O
> --
>
> _________________________
>
> Website:  http://www.overspianos.com.au
> Email:      mailto:ron@overspianos.com.au
> _________________________
>