Pipe bending formula?

[DRex1]

Does anybody know of a formula for bending tubing into a circle?
This is my situation. I want to make a 8'circumference, so at how many [red]'X' [/red] inches do I put [blue] 'Y'[/blue] degree of a bend in the tubing? AND the same thing for a 14'circumference...

I hope Ive described this well enough

Thanks,
Searching Fabricator

 

[JStephen]

You call up your local steel fabricator, and tell them you would like to get pipe of X size and wall thickness rolled into a circle. They do make machines that do this (and also roll angles). Shop around a bit, prices for this can vary tremendously. Figure you'll need a couple of extra feet of pipe to trim at the ends.

In answer to your question, for a polygon, as I recall the sum of all the bends equals 360 degrees. (not the sum of the interior angles, but the offsets from a straight line at each place). Anyway, so you'll need 4-90's or 6-60's, or 120 bends 3 degrees each, whatever you want to do. If I was going to do it this way, I'd figure the smallest angle bend I could make, and do a good (consistent) job of it, then divide the length of that pipe by the required number and go at it. How many bends it takes to look good would be in the eye of the beholder, I guess. You'd be limited by your equipment as to how close together the bends could be, too, I assume?