ArtMetal

Uhh- Gloves?
Really there are all kinds of modern inventions that make this much easier.

You can use a pair of Vise Grip locking pliers to hold the hot steel.

But I still dont see exactly what you think you have accomplished by heating up a spring. It is still a high carbon steel, and most likely, even leaving it in the embers, it hasnt annealed very much- its gonna be HARD. Even straightening it out is going to be quite tough- that particular alloy and manufacturing technique was chosen precisely to make it the most difficult to straighten.

Look in the yellow pages under steel, go buy a piece of mild steel- A36, flat bar, the size you want. Already straight.

Then you can just cut it with your hack saw, and file it.

No heat is needed. For one Boar Killing event, you just dont need an heirloom quality, hardened and engraved Highlander style blade.

If you really want to learn how to do this right- my advice above, about the Weygers book, and classes at the community college still hold.

If all you want is one sharp item, to kill one boar, un heat treated, ordinary old mild steel will do it just fine.