The curve was the first thing I did after cutting the piece to size. You could use a pipe but I used an old round hammer head that looks like a piece of solid pipe. I clamped it halfway in my bench vise and took a hammer and went to work. I just kinda formed it over it. It's a lot easier with aluminum than steel and that is why I bought aluminum. LOL It's still plenty thick enough that it's good and solid. I would shape it then take it over to my machine and see how it fit. Just kept adjusting it.
Art