On further reflection, I'd run the two outside rollers as flat
cylinders, run the center (movable one) with the correct profile. Make
multiple passes. That will force the flat section to stretch, leaves the
flanged area untouched until the end.

Ed Huntress wrote:
"RoyJ" wrote in message
...
If you read up on the roller mfg, they do ANGLE IRON rolls with the leg
***IN***. Sure, they have limitations on how long the leg is but it can
and is done every day. For the angle iron, the roller die has to have a
suitable slot so the inward leg is constrained while bending. It is being
compressed so it will expand (the web will get thicker).

Yeah, I read it, and I visited a number of roll-forming operations when I
was writing for fabricating magazines. Again, the thing to do here is to
talk to a jobber or equipment manufacturer. I don't think the dynamics will
work out, Roy.

Without making a long story out of it, the forces involved in bending angle
iron or channel apply the stretching (outside leg) or shrinking (inside leg)
to the web (the leg) in such a way that there is no lateral load on the web.
Yes, it needs constraint, because it will seek relief by moving in or out,
but there is no *resisting force* encouraging it one way or the other. If
you can keep it from starting to wrinkle with a lateral guide roller, you
can overcome that tendency of the web to move sideways to seek relief, and
you'll get it to shrink, if you apply enough force.

With the angled web (the flange, or the cone shape) the resisting force is
trying to flatten the web back into its original plane all the time. It's
always pushing against the outside restraining roller, assuming you're using
an outside restraining roller. And the force trying to press that web flat
is considerable. In this case there is not only a tendency for the web to
resist compression (shrinking) but there also is a force trying to *relieve*
it: the resisting force that's trying to flatten the web back to its
original plane.

This is going to produce a lot of wrinkling. I'd bet on it. But I would talk
to an equipment manufacturer before betting money on anything here one way
or the other.

For the OP's profile, the main web needs to expand, leaving the inward
flange at close to the original diameter.

Ed Huntress wrote:
"RoyJ" wrote in message
...
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.
snip

OK, but I don't see it, Roy. The angled flange, or cone section if you
prefer, is going to wrinkle like crazy if you try to do this on a roll
former. Custom roller profiles won't help, IMO. Rolling a perpendicular
angle is a lot easier, because the leg is not trying to spring to the
outside -- they just constrain it like the walls on a piece of
rectangular tube.

There just is no way I can see to apply the force necessary to compress
an angled flange progressively, so that it doesn't wrinkle, with a normal
roll former. The forces required would be huge.

But maybe the OP will want to call a roller manufacturer or a jobber and
see what they say.

--
Ed Huntress