[pianotech] Magic Line?

[John Formsma]

Yeah, I knew what it is.  Just wondered why it's called the "magic line."
Does it have to do with where the arcs intersect?  Or, that that magic line
point of intersection is a point of most efficiency?

--
JF

On Mon, Mar 16, 2009 at 12:53 AM, <PAULREVENKOJONES at aol.com> wrote:

>  John:
>
> Since you don't know this, obviously you are not on the "need-to-know"
> list, and if we told you, we'd have to kill you. And here in Chicago, Guido
> does good business.
>
> Actually, it's quite simple. The one being talked about mostly is the line
> (which can be created in reality with string or thread, and can be seen in
> an action model with a straight edge) from the balance rail hole center at
> the key bottom extending to the whippen center. Ideally, the line would be
> intersected by the capstan top/whippen heel at half of the key travel. The
> capstan top and whippen heel rotate in opposite directions "bearing" on each
> other in different ratios in the counterbearing arcs (involutes) of travel.
> The leverages of the whippen and key change throughout that travel.
>
> That's it. No magic at all. Now, which knee-cap do you like the best? :-)
>
> Paul
>
>  In a message dated 3/15/2009 11:01:31 P.M. Central Daylight Time,
> formsma at gmail.com writes:
>
> I'm going on the notion that the only dumb questions are the ones that
> aren't asked. Go easy on me, OK? <G>
> Why is the "magic line" called the "magic line"?
>
> --
> JF
>
>
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