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.


Ed Huntress wrote:
"RoyJ" wrote in message
...
The easiest way to do this is in a good sized roll bender...

"Good sized"? Roy, 15mm material thickness is over 0.59". The cone is
attached to the straight cylinder, so one edge is going to have to be
stretched or the other is going to have to be shrunk -- or a little bit of
both -- while you keep that blend radius intact.. And this is stainless! You
can't just roll it. you have to iron it at the same time, and ironing it out
so it doesn't twist is going to be an extreme metalworking job.

Unless you have access to the machines used for making Saturn V rocket
nozzles, I think there is a problem here. d8-) The forces involved are
astronomical.

--
Ed Huntress