Ok, so this my seem like a stupid question and I'm certainly no math whiz, but can anyone help with how I lay out my curved stage? I have a front wall that is 160" wide and I would like to build a stage that is 36" out in the center and curves to 24" on the sides. I've stared at the floor long enough without figuring it out so I thought some of you could enlighten me.

If you take a flexible piece of wood and have a center joist in your stage cut to about 36" and 2 edge joists cut to 24", bend the piece of wood between the 2 edge pieces. The stiffness of the wood will effect your radius.

Alternatively you would use an ellipse to make the edge. Take two points, one on either side of center. Place a nail at each point. Make a loop of string that is bigger than the distance between the two points, use a pencil to pull it tight and draw a line for the curve. Alter the distance between the two points or the length of the string to change the curve. There would be ways to calculate it, but I don't know how.

Hope this helps

Greg

From a loooong time ago not very far away

http://tedwhite.homestead.com/Stage.html

That is a huge arch for this method,(it works real well for arched door openings though) but if you want to be a little more accurate, use the formula I learned as a carpenter:
a2 + b2 / 2 = c (that's a & b squared BTW)

In this formula, a= 1/2 of the distance of the arch, so 160"/2, so for you a=80"
b=the height of the arch at that previous width, so for you 12"(36"-24")
c= the radius of the circle that will give you the arch...

(80)2 + (12)2 / 2(12) so: 6400 + 144 / 24= 272.5"

This is usually where the problem comes in: finding space to make a 22' radius! :eek: (We did it on the wide open floors of new houses before the walls were built...)

I would head to your driveway(if possible) and bring your plywood pieces and lay them out and make up a string compass and draw the arc, jigsaw it out...

Kind of a pain when they get this big, but maybe others can benefit from the formula...

Garen

Bang a nail in the middle where you want the apex, another two at each side where you want it to stop. Get a bit of conduit (the thicker less flexible stuff) and bend over the middle nail and anchor with the two side nails.

Or go with the math method, but you might not like the look of it, you can move conduit as much as you like until you're happy

You can draw the arc out in the middle of the room with a string. cut all your framing to fit the drawing then move in place. This was for my marquee over the stage.

http://i23.photobucket.com/albums/b393/bigmouthindc/DSCN2604.jpg

Also a FYI, two layers of 3/4 inch PVC lumber works great for the curved front edge instead of using lumber with a gazillion kerf cuts.

Thanks everyone for the replies. I figured out the flexible wood method a little while after posting the question. I'm going to try the other methods also to see which one gives me the best result.