This is not quite a mod but the way that this knife was made is very interesting.
The subject of today is a Michael Morris Friction Folder knife from the British Blades forum group buy. It is a very simple design. Being a friction folder it does not lock and the blade is kept open by pressure on the tang. The hollow ground drop point blade is made out of an old Nicholson file.
According to Mr. Morris, a file is one of the best sources of carbon-rich steel to make a knife out of. What would a file’s job be if not to cut into tough materials?
The file is heat treated so it is not brittle, then it is ground down into a knife. I guess you could say that a file was modded into a knife.
Voila! and he turns an old file into a new tool. You can even still see the file patterns on the blade. The tang also functions as a bottle opener. Very smart.