There is a simple method for DRAWING one that involves the use of two pins
and a length of string, but after drawing it, you would have to manually cut
it. If anybody is curious enough, I'll write it up and post it; that is,
unless someone else does it first.


Flash



wrote in message
...
On Jan 19, 5:09 pm, axolotl wrote:
Years ago, Errol Groff posted some pictures of some packaging prototypes
he had made. The bottle top was shaped in an ellipse. Can anyone give
the procedure for fabricating an elliptically shaped object using a
rotary table, given a rectangle size that contains the ellipse?

Kevin Gallimore

I can remember drawing an "ellipsoid" using a compass back in grade
school, was part of some kind of drafting thing, Was drawn as 4
separate arcs, I remember that Left some sharp points at the ends of
the major and minor axes, which could be dubbed off afterwards if you
were actually cutting stuff. Don't remember much more than that.
Maybe an old drafting text would have the procedure.

Or you could build an actual ellipse generator, I've seen some for
cutting photo matts, too. Isn't much more than a pair of cross slots
with sliders and a bar linking the two. As the bar goes around the
end traces out an ellipse that depends on how closely the two sliders
are linked for major and minor axis ratios I suppose it could be
hooked to some sort of pantograph linkage to get smaller ellipses.

Stan