When I built my '38 pickup 16 years ago they didn"t have lower door skins or cab corners available so I made my own. For the door I used a flat piece of sheet metal that I had the supplier form a 90 deg break along the bottom edge. This gave me a good starting point. I fit it to the door and cut it to length to allow the ends to fold over. FYI: I bonded mine instead of welding it, worked great.
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