I want to "cheat" and make a pair using The Book method of frame construction - "real" repros cost over $200/pair!

So how do I draw the traditional curve across the top of the glass? It looks different from the elipse you get with a loop of string and two center points.



[Edited on 18/3/06 by carcentric]

using a set of french curves will get you the right top

Sometimes you can get the curves by using tangential circles. Two or more can be common to get what you want.

Syd.

Some methods of drawing ellipses about half way down this page. Might give a hint at drawing your curve. Easiest thing might be to find something with the curve you want in a book or draw it up in a cad/drawing package and use it as a template.

http://www.du.edu/~jcalvert/math/ellipse.htm

Cutting along the line and grinding it smooth will be the real trick.


[Edited on 18/3/06 by iank]