Hi Ron, is that the amount of arc over the 14', 6"? I think I would draw the thing out, to scale, on deltacad or sketchup and take measurements every 6" or so to plot out a full size template. go from there.

 

Hi Ron

I have a jig for just that type of job,,,it's bowl and arrow type jig, a stick with a string..set it and they all come out the same....
I have not posted it b/4 but I will if you want to see it..

oR
Flexible Curve Ruler, some have lead in them but the one below is plastic,the lead ones are better and will hold the shape you set up. (lead ones from Grizzly)
use the item below
Router accessories 3

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Use 2 finish nails set at 14'. Rip a flexible 1/2" stick out of a 16' 2x4 run longer than 14'(1/2" x 1-1/2" no knots) or something similar. Find center & push to your 6" rise. Scribe the outside of flexible stick. Move nails up 1" & repeat for your 1" thickness. The arc should be 16.34*. You didn't say if the 6" was an inside or outside measurement. Just adjust for that but 2 finish nails & a flexible stick should be all you need to accomplish your task.

 

Are you making headers or arched ceilings or trellises?

I think ellipses and ovals are pretty much the same thing, "a stretched out circle" although one is stretchier... er than the other. How accurate, (symmetric) the ellipse/arch is to be depends on the number of blocks and their positions are on the ply.

In the past I've made a couple 3 arched garage door overheads and breezeways.

In your case a sht of ply ripped in half along the 8' and 2X to hold them tight together.
Block the ends with 2X for the 14'W and a block in the center at the 6"H.

Pressurize a water hose from the house, thoroughly bleed all the air before closing off the end, (good water pressure helps) keep the house feed open.

Set the hose in the jig, butt it to the blocks and mark the perimeter.

 

Hi Ron, James, Sofasurfer:

Are you making headers or arched ceilings or trellises?

This is part of a design theme throughout the house and outside. It is an attempt to unify all of the parts, the terrace in the back, break up the central wall with built-ins, and become a design element in the kitchen and bathrooms.

I think ellipses and ovals are pretty much the same thing, "a stretched out circle" although one is stretchier... er than the other. How accurate, (symmetric) the ellipse/arch is to be depends on the number of blocks and their positions are on the ply.

I figure the 14' ones will be "sort of" but once one is created, the others are easy duplicates. The interior ones will be 4'-6' and will be much easier to do but will be one-off each.

In the past I've made a couple 3 arched garage door overheads and breezeways.

In your case a sht of ply ripped in half along the 8' and 2X to hold them tight together.
Block the ends with 2X for the 14'W and a block in the center at the 6"H.

Pressurize a water hose from the house, thoroughly bleed all the air before closing off the end, (good water pressure helps) keep the house feed open.

Set the hose in the jig, butt it to the blocks and mark the perimeter.

Excellent mechanics. Well worth the examination and attempt.

The carport is 28' long with two "bays" between pillars supporting the roof. The front and back are 14'. These are "detail panels" that go below the beams and hide indirect lighting. Would you use a single circular arch, an ellipse or an oval?

Thanks for the help guys.

 

Doesn't anyone watch This Old House? Tom will show you how to do it...

http://www.youtube.com/watch?v=so81BLxh4yA

 

Rick R. of the RWS will so you a easy way on the The Woodworking Channel Video Library ,see part two of the Oval mirror ..

All done with a small framing square

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Bob I think he needs 14' long not 14"

 

Hi Ron, is that the amount of arc over the 14', 6"? I think I would draw the thing out, to scale, on deltacad or sketchup and take measurements every 6" or so to plot out a full size template. go from there.

I agree with jschaben posting I have drawn the shape you require and have included the measurements for each section only I spaced them out every foot.

Vertical heights from the centre out 12" spacing
(1) 6"
(2) 5.76"
(3) 5.44"
(4) 4.95"
(5) 4.23"
(6) 3.14"
(7) 0.5"

 

Thanks Tom:

That will be handy. I was going to do it on quad paper but you saved me the work.