At 9:43 AM -0700 4/7/03, Delwin D. Fandrich wrote:
>As I'm sure you all know the bottom face of the modern agraffe is undercut
>somewhat. The idea is that the agraffe can be snugged down and then forced
>to align with the string, simply flaring out the bottom of the agraffe.
After an initial reefing down on an aggraphe, that flaring out is
clearly visible (and could be an indication on a factory fresh piano
whether aggraphe installation was a high or low skill job). I've
never seen the threads pulled downwards by ham-fisted
over-tightening, which would suggest that the undercut is the spot
designated to absorb this stress.
That's why I like Ron's idea. It allows a proper installation without
tossing the stress-relief area in the can.
>With these agraffes it is quite easy to get at least another
>half-turn beyond the initial seating.
Given that I've never seen a manufacturer-supplier torque
specification for aggraphes, and that the conventional story for
popping aggraphes has been the accelerated crystallization of the
brass in response to such stress, I've always wanted to be on the
conservative side. Heck, at 45º beyond snug, i usually get the tiny
screeching sound of dry brass on cast iron, and it makes me nervous.
I'd assume (in the absence of torque specifications) that 30º should
be enough to eliminate any chance of the aggraphe buzzing against the
cast iron.
Bill Ballard RPT
NH Chapter, P.T.G.
098783 EA Hamburg Tuning Pins 4/0 2-1/2.......$72.00
T5591600 1PC Key Flame Guide
...........My two favorite catalog items (Steinway 4/96, and
Yamaha
respectively)
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