Continuation of research.
I finished the tool. I used a lathe. The angle difference between the tools is 2 degrees. The smaller half of the tool is sharper minus 2 degrees. Both tools also have a semicircular conical surface. I did not have to grind the tool. I have made exactly to the required size. Note the way of clamping to the lathe.
I tried to bend the angle and shape the profile. Another idea was to make the frame whole without welding.
Using a bead roller, I made an edge and bent the sheet in the required arc. The second step is shaping the profile.
The sheet must be trimmed because it curls in sharp bends. It is necessary to shrink using jaws. It is possible to modify the shape afterwards before last forming.
I think the last attempt will be the best.
Now I have to make a template and paint the frame profile on sheet metal.
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