Before you guys put a lot of work into files, because some of the newer ones are case hardened (lesser quality steel) & aren't good for blades, I'd recommend heating the tang to non magnetic & quenching it in room temp water.
Then put on a pair of safety glasses & gloves, put the file in a vise, tang up, & hit it smartly with a hammer. . . If the tang snaps off, or shatters like glass, the file's a good one for making a blade. If it bends, or just cracks,or takes more than one sharp rap to break, it's too soft & most likely won't be hardenable enough for a blade. When you quench a blade, you want that hummer to be as hard as it can be. Then you'll draw the hardness back during the tempering process.
JMO . . (based on making blades from files)
Dick,
If the scissors are stainless, they may have to be cryogenically hardened. Some types of stainless require entirely different hardening techniques, yet other types, (martensitic) are hardenable by using the standard tool steel methods.
The $50. Knife Shop by Wayne Goddard is probably the most down to earth, getting started making good knives on the cheap, book out there today. It's mostly about forging blades, but there's enough about tools,heat treating, stock removal (filing/grinding) info in it to make it worthwhile for any beginning knife maker.
Larry