[pianotech] Magic Line?

[David Love]

I don't think there's any magic to why it's called the magic line.  Someone
just came up with it as a description for the lines of convergence.  

 

David Love

www.davidlovepianos.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of John Formsma
Sent: Monday, March 16, 2009 5:52 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Magic Line?

 

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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