Key Leads and Inertia

[Bill Ballard]

At 8:32 AM -0400 6/13/03, David C. Stanwood wrote:
>The magnet thing is more interesting.  The gaps of the
>opposing back magnets and the attracting front magnets may be set in
>various ways so that the force is more at the top - less at the bottom,
>less at the top - more at the bottom, etc...  but again these subtle
>differences are lost in din of dynamic playing force...

Thanks for the photo, David. It explains alot. Certainly having a 
pair of them (one at each end of the stroke) opens up alot of 
possibilities.

I was surprised that the front pair would be attracting instead of 
repelling. While attraction at the bottom of the keystroke (when the 
hammer was nearing the string) might provide some terminal 
acceleration (and a boost in "escrapement"), wouldn't it also be at 
cross purposes to the return? Granted that the contribution of such 
helpers is constant regardless of how much force the pianist applies, 
granted that with a hard non-checked hammer blow the hammer's return 
(and thus the parts below it) is a matter of rebound, this would not 
be an issue in the "hard zone".  But is the return of the key with 
attracting (instead of repelling) front magnets affected during the 
"soft zone"?

Obviously, the rear magnets want to be repelling, to lighten the BW. 
What do you know about the decision to use attracting magnets in 
front?

Bill Ballard RPT
NH Chapter, P.T.G.

"All men are dogs. Some just make better pets".
     ...........Recently seen on back bumper
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