Operative word is 'roller'

A quick google brought up this mfg: The largest unit on this page
http://www.wikco.com/rbndr.html
will easily handle this cross section. Most of these roll benders will
operate in either the vertical position (shown) or horizontal position
(better for this project) There is a max size calculator at the bottom
of the page.

You would need to make one male roller and two female rollers. These
would be some pretty massive chunks of tool steel, probably 8" in
diameter by 9" long (1/2" flanges to contain the 8" material on each
side). The rollers are easy to make: turn on a lathe, bore the center
hole, broach the keyway, heat treat.

The OP's shape would require that one side would need to shrink, hard to
do in a roller. In real life, multiple passes through the roller will
likely stretch the outside some. That makes the final diameter a bit of
a guess.

Final process would probably be: roll with flat roller (or in a big slip
roll), weld the ends together, start forming the angle leg of the
ring. I'd expect that you would need to cut out a section and reweld to
get the diameter just right. This is not an easy part to make but I'd
hope to get one finished ring out per 8 hour shift with a team of two.

BTW: the equipment in the shop that I interned in (just down the block
from BendTec) had an 8'x1" shear and an 8' slip roll that was quite
happy with 8' x26' of 3/8" plate, used to make tanks and industrial
furnace duct work. Lots of similar places around the country.

Ed Huntress wrote:
"RoyJ" wrote in message
...
These guys are somewhat local to me. IIRC, they have a suitable roller.
http://www.bendtec.com/architec.html

I'm inclined to believe the OP is real on the thickness, the drawings show
a pretty hefty thickness in relation to the width. The blank would be a
20' piece of 5/8"x 8"(?) 304. Calculated weight would be 336 pounds. I
haven't priced stainless lately, not calibrated on that one. I'd certainly
hope to get it for less that $5 a pound, that would put the piece under
$2000.

My biggest concern is the OP may think that a fabricated piece will hold
the same tolerances as a machined piece. BTDT, had a very unhappy
customer.

I can't see how you'd do the angle (cone) and the cylinder (flat) on a pipe
bender, Roy, but I'll be interested to hear if they'll give a quote, and
what it is.

--
Ed Huntress