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Not with a razor, but close… in another life I used an old file to make new cutting tools for a lathe... Use the torch to soften the steel, cut it up, re-harden, and grind to shape. They worked...

Yes start with the 3-5 $ a Lb steel, a little elbow grease, a few tools and you may just end up with a serviceable razor who knows it may be a better razor than a new one.

Bastard file from...

Metallurgical content or the refining hardening/tempering process?

Sure there may be files with questionable metallurgical content but many things in life is a crap shoot anyway… even a new...

I am sure a straight razor can be made from flat file. The high carbon in the steel should be good for razor making.
You get ahead start because some flat files already have the basic shape...