[raffman]

I'm thinking a two part die used in a press would do it. Would have to follow a straight line too. I'd like to try it on a stock HD narrow glide 21" fender. Anyone ever try it? Would be great if someone already made the die. I think a bead roller would be too wide and distort the fender................

 

[Destralo Roach]

A guy did that with a Hoop Roller, made his own dies, made ribed fenders real easy.

Modifying a allready made fender to have a rib will be a chalenge for certain reasons........

....Roach.

 

[ELpolacko]

Bead roller or a hammer form would do the trick.

I went the more complicated route, I built a helve hammer and made custom dies. This was for the bottom of a 1932 Ford grille shell, but you can see the process just fine.