To form a cylinder from sheet, you need to first bend the few inches on
end of your sheet to the correct curve, using either a press brake or
cornice brake, then use a slip roller to roll the rest of the sheet
into the proper curve.
Doing it any other way is just too much damn trouble.

You could have this done by a sheet metal shop for maybe $20 - $30.

You could form the cylinder in 2 pieces by using over length pieces,
bending them around a curved object with a smaller diamter than your
finished size, and then cutting the curved bits from the middle of each
bend.

It is always better to over bend and then un-bend than to under bend
and then try to force the edges together.

For a 15" diameter curve try something 12" - 13" diameter.








In article , cdg
wrote:

Hi,

I have a 16" x 48" piece of 304 Stainless Steel 1/8" perforated sheet
metal, about 1/16" (.065) thick. I want to bend it into a 15"
diameter x 16" high cylinder. Is this something that can be done
(manually) without any special machinery?

The method I had in mind would be to obtain a 16" length of 15"
diameter pipe (or perhaps bolt a few 15" diameter wheels together to
form a 16" high cylinder). This would be bolted or clamped to a fixed
object. I would then clamp one (16") side of the sheet metal to the
pipe with a piece of bar stock and a couple of c-clamps. Another
piece of bar-stock would be clamped to the other side of the sheet
metal, and I would then slowly bend the 48" length around the pipe.

But then, what can I do to retain the cylindrical shape? I assume
that 1/16" stainless will want to spring back with a vengeance. I've
considered clamping it in place and then hammering and/or heating it.
I've considered using a smaller pipe and bending slightly past the
diameter I need. But I don't know how much smaller a diameter to use.
I need to have a reasonably "perfect" circle, and I don't want any
kinks.

Is this a practical thing to attempt, or should I try to make friends
with someone who has a slip-roll forming machine.

Any advice would be appreciated.