Eliptical Arches

I think if I had to pick one thing that a CNC router can do unquestionably better, faster and cheaper than a human can do it, it would have to be the cutting of ovals and other elliptical shapes .... I tried a few back in my early days of carpentry and custom sash work and they are about impossible to do easily and gracefully by hand ... I am the proud owner of an Ovalcompass, a two axis manual compass like thing that I bought in the early 80s ... kind of works ok if youre coordinated and careful and the elipse youre drawing isnt too big. Two nails and a pencil and string ... been there, done that .... not much fun .... But ovals in CAD ???? Sweet. All day long, any size you want, perfect EVERY time.
Heres an example. The challenge ... cut four different length half ovals, all the same height, in 12 different pieces of 3/4" pvc board, with matching offset grooves for 1/4" jamb material, and get everything to line up inside and out, starting from the centers of the boards outside and the ends of the boards inside .... Yeah, maybe you can do it by hand, but Ill race ya ... Actual set up and run time, about two and a half hours hours plus a little programming ... click the photos to enlarge them ...
Heres the before .... the pvc is fitted and the joint is in the center on the outside, behind the keystone ...
The joints on the inside are behind the beams where there will be filler pieces added later... the oval openings are the width between the vertical framing ...
All the same height ... four different widths. One dimension was only 1/8" different from the other ...
All in, all done .... perfect reveals and my hat is off to the architect, Ramsay Gourd for another elegant design ... Hes got a nice website and lately has been writing a blog on architectural design ... The builder is Mark Breen and the gentleman who organized the pvc department was Eric Gutbier, who was on hand to identify which part was which as Trevor cut them ....

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