A sheet metal brake would be a nice addition to my shop but there simply isn't any more room in Garaj Mahal. Fortunately, most of my work is miniatures so my metal bending requirements are quite modest. Still, it's nice to have a nice clean bend line.
So I built a miniature brake consisting of two identical assemblies. A 1/4" thick aluminum plate supports a 45 deg angles steel block held in place with two bolts that pass through both and are secured by hexagonal brass spacers that also serve as legs when the tool is fully assembled.
Here you see the two parts...
and here it is assembled with a typical size piece of sheet metal in place.
It's obviously not a production tool since it's fiddly to assemble. I don't mind since I don't do that much bending.