How to draw a perfect oval??

[Negativecreep0]

I

[Ed_McCarron]

Size?  If its under 8.5x11 (or bigger, if you have the corresponding printer) print/plot it 1:1 and attach that paper to your wood.  Cut thru the whole thing.

I do it with autocad all the time.  With the D-Size plotter I have, it'll do 44x30 or something silly like that.

[mahuti]

you could use a program like Adobe Illustrator, Macromedia Freehand, CorelDraw or Inkscape (freeware) and print like he said, or use your favorite cad software.

[PetitMorte]

In order to draw an oval with string, you need to use TWO nails, on the centerline.  Also, tie the string into a circle, and put ot over the two nails.  adjust the space between the nails, and the length of the string to get the curve that you want.

The closer together the nails, the taller the oval will be.  The farther apart, the more flattened the oval.

It takes practice.

[krick]

In order to draw an oval with string, you need to use TWO nails, on the centerline.

[rdagger]

I marked a half oval cut on my cab using a clear plastic refrigerator water line.  You just mark the 2 end points and place the plastic hose over those points.  The hose will lie on a smooth curve.  Then you just feed or remove hose to adjust the height of the oval.  Once I got the curve just right I secured the line with some masking tape so it wouldn't move when I traced the cut.

[Avery]

Woodworkers often use a piece of thin stock with a hole drilled in either end and string through it.  You keep tightening the strink until you get the curve you want.  This gets you an even curve, but you won't get those near 90 deg curves at the end that a true elipse has.

You could divide your span up into a couple sections and readust that setup to give you something very close to a true elipse, if that's important to you.

[bjk7382]

Back when I was in 8th grade they had us draft a perfect oval for one of our first projects. Actually figuring it out with only a compass and a ruler will yeild a perfect oval with the dimensions that you need. I really liked drafting on a board and making true blueprints with the machine that smells like amonia. Using AutoDesk and a plotter took the fun out of it.

[Ed_McCarron]

"true blueprints with the machine that smells like amonia."

Diazo paper?

[DrewKaree]

An old-fashioned mimeograph?  Wait, is that redundant, or do I have to say it again for it to be redundant twice?

[nostrebor]

"true blueprints with the machine that smells like ammonia."

Diazo paper?

Heh.

We still use a blueprint machine at work for random copies. I'm sure I'll die of some strange cancer related to inhaling ammonia. It's always funny when someone comes into the room that isn't used to the smell. They usually cry, and run away.

[Mark70]

Your best optoins are in order:

-have a full size pattern printed.  (post your dimensions here and I'll do a pdf you can take to a print shop.

-construct it using a compass like suggested above.  Takes  a little delve back into those highschool geometry books.

-use the nails and string solution.  Not most accurate but works for things like a drywall bulkhead.

[gw71mgb]

Even in Elementary School, I always thought that the fumes from the Mimeograph machines couldn't possibly be good for you.

[javeryh]

Just do the geometry!

http://mathworld.wolfram.com/Ellipse.html

[Matt Berry]

The simplest method besides plotting and string and such. Is to take a thin piece of wood or plastic that is semi-flexible, drill holes in the end, run a string through the two holes and tighten until you acheive the desired results. There are places where you can buy these already premade, leevalley comes to mind.

[lcddream]

Using AutoDesk and a plotter took the fun out of it.

it's never fun at 8+ hours a day whether you use autocad or not.

 

[Mark70]

Using AutoDesk and a plotter took the fun out of it.

it's never fun at 8+ hours a day whether you use autocad or not.

 

Well, the early days of Autocad and pen plotters weren't much fun at all.  It's much better now that you can use your windows plotters for small format.  I printed my CP pattern on 8.5 x 11 and taped them together.