How to draw/figure the door arch? Pompeii Oven Construction Discuss How to draw/figure the door arch? in the Pizza Oven Design and Installation forums; Hello, With an opening 19" wide x 12"high, how do I figure the arch? I want to build the form ...

[kimemerson]

Hello,
With an opening 19" wide x 12"high, how do I figure the arch? I want to build the form for setting the arch brick but it isn't a clean hemisphere, it's more elliptical. So I guess that's my question: How to figure out the arc of an ellipse. A quick Internet search turns up that I will need at least a rudimentary MIT education but I have to believe there's another approach. How about eyeballing it?
Thanks
Kim

[ThisOldGarageNJ]

Hi Kim,
I made my own compass rom an old piece of wood, Made a spot for a carpenter pencil on one end and a sharpened screw on the other, Drew up the bottom and 2 sides of the arch on a piece of plywood, Using my homemade compass to form a nice looking arch across the top, Moving the compass up or down on the center line changes the height of your arc,, Sounds a little confusing, But I may not be explaining it as well as i should be, Hope the pictures help

[fxpose]

I think the degree or style of curvature of the arch should simply be pleasing to your eyes.

[RTflorida]

I think most of the forum would tend to agree with fxpose, appearance and fuctionality are the key.
Is it just me, or is the recent new wave of builders a little too focused on the math and creating the "perfect" (based on their intense calculations) geometric shapes?
Just my observation.
RT

[kimemerson]

I just solved it myself mostly by eyeballing it. Looks good enough. thanks

[christo]

May not work for all, but I drew the rough shape of the arch I'd like on cardboard. Stuck a nail through the cardboard at each intersection of wall and arch, tied a loose string between the two, set it upside down so the string would hang in rough approximation to my sketch and corrected my sketch to match the cantenary curve of the string.

Even then, I think I may have deviated a bit from that curve to make something a bit more pleasing...

[jmhepworth]

I eyeballed mine on a piece of cardboard and then folded it in half to make it symmetrical.

Joe

[ThisOldGarageNJ]

hey JM

simplicty..... I think you have the best and easiest idea

Mark

[RTflorida]

jm, thats simplicity at its best......does anyone else remember in kindergarten when they taught us to fold our paper in half before cutting to make a symmetrical shape?

RT

[Spunkoid]

I am making the arch the same curvature as the oven dome and floor and am using the floor template as a guide for the arch. I cut a piece of plywood the width of my door then drew the arch on them tracing the arch from the floor template.
I have not built my arch yet but it should work.....