How to Flange Sheetmetal Hole ?

How can someone effectively flange a hole in sheetmetal?
ie: 5inch Dia. hole with .25inch lip bent at 45degrees around the circumference
of the round (or sometimes oval) hole.

I need to do this and have not figured it out yet? ... any ideas would be
helpful ..

 

To achieve this you'll need to use sheetmetal tools

 

More specifically Form Features I have an example, if you would like.

The help on form features is usefull too. Although using form features will
not yield a correct flat patter.

Corey Scheich

 

You could make a forming tool to do this pretty easily. If you check
out some of the examples that come with SolidWorks, creating them is
not that difficult.