[TheForge] Ellipse generator?

[xlch58 at swbell.net]

Here is a simple mechanism for drawing one:

http://www.physics.montana.edu/demonstrations/video/1_mechanics/demos/ellipsedrawingboard.html

The mechanism for describing an elipse in machinery that I have seen 
consists of two 90 degree intersecting slides with an one arm pivoting 
on each.  The end of the arm descrubes an elipse.  They are sold as toys 
called "do nothing machines" one is shown here:

http://woodenuknow.com/donothingmachines.html

Charles


Andrew Vida wrote:

> Folks,
>
> It's driving me nuts.  I cannot, for the life of me, remember how to 
> put together a mechanical ellipse generator.  They are very simple 
> devices but my brain just refuses to give it up.  Last one I saw was 
> at some smithing event several years ago.  For some reason I recall 
> that Bob Bergman donated it to an Iron in the Hat, but I may be wrong.
>
> Anyone have any links or images?  Web search produced nothing that I 
> could find.
>
> Thanks,
>
>     -Andy
>
>