Annealing file to make knife?

[72chevy]

I will be attempting to make my first knife from a farrier rasp this next week. How do you guys that have done this before anneal it so that you can work with it easier?

[Kevin Smith]

Start a fire in your pit and drop it in the coals and leave it overnight.

[vgoodson91]

Annealing file to make knife?

Yea just build a fire and set the rasp in. Try to keep it flat and level. It is going to get red hot which is what needs to happen but that also means it can warp very easily. It's easy to hammer it back flat but makes less work on you the less it warps.

I usually turn mine and make sure that the entire file or rasp is glowing red, then push it into the coals/ashes and come back for it tomorrow. Don't set it out to cool, you want it to cool down slowly with the coals to anneal correctly.

[72chevy]

Thanks. Does it need to get red hot to the point it is non-magnetic?

[72chevy]

Gotcha, thanks!

[paintman]

yes non magnetic

[GrapeApe]

If I anneal in coals like that, I sandwich the file between two pieces of scrap steel so that it stays straight. Little bit of effort early on saves a lot of work down the line straightening.

I used to have some steel that I would bolt together, now I just wrap the thing in bailing wire instead.

[SamHarper]

I do a bunch of files at a time. I light a fire in my fire pit, let it burn down to coals, put the files on it, build another fire on top, and let that burn down over night. I make sure to burn enough wood so that when it's burned down to coals and ashes, the files will still be completely covered so they'll cool slowly.

They always come out warped, so I straighten them by setting them on block of wood and applying a c-clamp.

[72chevy]

I appreciate the help, I wouldn't have thought to cover it in the ash to leave it overnight. I was also informed that I need to make sure it is not case hardened before I get too far along. It is an old Nichols rasp so hopefully it will be a good one.