The flattened part is trimmed with a shear to the proper shape- Voila!
But wait! What's that leaning against the propane forge?
Looks like a section of high carbon cable...the end is fluxed and welded, first, then clamped in a vise and when yellow hot twisted as tight as I can get the first foot or so.
Then the tightened part is fluxed and welded into a square billet, which will make a beautiful blade!