[pianotech] capstain/wippen angle, was: key position at rest

[Nick Gravagne]

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Mike Spalding
Sent: Sunday, March 15, 2009 8:26 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] capstain/wippen angle, was: key position at rest

 

Mike S. asks: Does anybody really believe that the top of the capstain, or
the heel of the wippen, are shaped like true involutes? 

 

I know, seems a bit of a stretch. If memory serves (and it doesn't always),
I believe that the explanation was that the slide path, and not necessarily
the capstan top or the whip heal, follows the involute curve. This slide
path would have to be precisely drawn out, plotted, graphed, extrapolated
and formularized in order to evaluate what kind of a curve it really
describes. 

 

I think that the power transmission idea holds more promise, but I would
like to investigate the involute as it too (or whatever curve exists) is a
clue to the power acceleration curve, if there is one.

 

This all may be relatively useless for the working tech, but since the
question routinely arises RE "what should do with these angled capstans and
sloping whip heal?" perhaps we can come up with a better answer.

 

Perhaps this has been done already. Any data out there?

 

Thanks again, Mike and Dale

 

NG

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