I need to bend 6mm x 40mm M/S flat strip into a 50mm diameter half round scroll end, it can't be done just with a hand jig, could i build a tool to do it cold, or will i need to forge it hot ?
I'd do it cold by hand round a piece of 50mm tube held in a vice and a long tube for a lever on the end of your bar, either clamp the end of your bar to the tube or weld something to the tube to trap the bar.
Bending 6mm into a 50mm circle is too hard to just do it by hand without some sort of heating,
I do this with handrails all the time, Get a small bit of tube 50mm and weld it to a piece of plate, weld a small stop out of some angle at least the width of the flat bar your bending about 7mm away from the tube to act as a stop.
heat your bar til nice and orange, and then put it in your jig and bend