butterfly

Fred Sturm fssturm@unm.edu
Fri, 09 Apr 2004 12:37:15 -0600


	One thing that did just occur to me: I was talking to the technical rep of 
Beckstein a couple years ago, and asked him if he wouldn't love to have 
Beckstein adopt the new Renner screw aadjustable butterfly wipps (provided 
as retrofit for Steinways by Renner USA). He said he wasn't sure that 
design was an improvement. As he explained it, when the standard butterfly 
is compressed, the spring arm slides out along the balancier, and thus it 
not only has the additional stored energy from being compressed, but also 
has an additional leverage advantage (it's acting at a point farther from 
the fulcrum). I guess meaning that the is "added zip" at the very beginning 
of the repetition function, providing a speed advantage.
	I have to say I was a bit skeptical that such a small leverage advantage 
would have a perceptible impact, but maybe it does. If this is one of the 
major reasons the butterfly has supplanted other designs, then the "Renner 
improved" is actually a step backward.
Regards,
Fred Sturm
University of New Mexico

--On Friday, April 9, 2004 12:26 PM -0400 Wimblees@aol.com wrote:

> I can understand that it might be more stable, but, as you said, only
> when it is regulated properly. But because it is so difficult to get a
> precise regulation on a butterfly, as opposed to the screw adjusted reps,
> it would seem to me that having a rep that can be adjusted much closer,
> and easier, would be preferred. But maybe only by technicians, and not
> pianists.
> Wim



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