best way to anneal mill file?

[IronMonkey]

I want to try my hand at making a mill file knife and would like some help annealing the blade.  Any ideas?  I have two propane torches and access to a mapp gas torch if that helps.  Going to start with a small knife, parring size or so.

[TimWieneke]

We have two definitions for annealing.  The first is "heating the steel to nonmagnetic then letting it slowly cool down as to soften the steel".  The second definition is "the proper stance for asking the wife to allow us to buy more bladesmithing tools".   :grin:

Seriously, from my experience both will work but the mapp will get you there quicker.  Try this.  Dig a hole in you backyard.  Start a fire or get some charcoal going with one of the torches.  Set some of the burning charcoal inside of the hole.  Put your file on top and hit it with the mapp torch until it glows red.  At this point, you test the steel to see when it turns non-magnetic.  You do this by putting a file in a set of pliers or vise grips and then touching the magnet with it.  When the steel is hot enough, it will cease to attract the magnet.  That's when you know the steel has reached non-magnetic state.  I would keep it at non-magnetic for just a little bit longer (for good measure) - just make sure you don't overheat the blade.  Now, put the rest of your burning coals on top until it's buried in a good 4 inches plus of charcoal, then leave it there for the night.  In the morning, it should be annealed.  I basically do the same process, just in my charcoal forge.  Any questions, just shoot me a pm.  

Tim

[TimWieneke]

I know a couple guys don't have a backyard and can't use the method above for annealing.  I started making knives while living in a 1 room apartment in Boston.  Here's an apartment/condo method for annealing I used while living there.  It worked pretty well for me.

Here's annealing for the condo/apartment dweller.  Preheat your oven to broil - hottest setting it will go.  Get some foil at least several layers thick.  Get a pair of pliers to hold the knife and a pair of pliers to hold your magnet, set your torch on the floor so you can pass the blade across the fire to heat it.  Setting a cookie sheet down and working above that can help not burn carpet/tile if you drop the blade (I did that about 6 times :-) ).  Heat the blade to the point that it is non-magnetic (same test as doing it outside).  When it's non-magnetic set it on the foil, set your file in foil inside the pre-heated oven (it's important that the oven be pre-heated for at least half an hour to an hour), close the door and leave the oven on hottest for an hour or so - after that you can turn the oven off, but do not open the door - you want the steel to cool down slowly.  This will anneal it pretty well so that you can work on it with a file.  FYI - the steel may not FULLY anneal, but you can get it pretty darn close.  Test it first by running a sharp, unnannealed file against it to see if the teeth bite into the annealed file or just skate off of it.

Tim

[IronMonkey]

I am waiting to get some old files from a patient of mine.  I am a physical therapist.  Then I will hunt down my two propane torches and my friends mapp gas torch.  Already got the magnet.  I have decided to get a 1x30 belt sander from harbor frieght, though I might start on the small knife first with just a file.   Either way I am probably going to have to go over to a friends house and use their garage.  No way on earth I am going to make my lovely wife spitting mad by doing that stuff in the house.  She would do bad things to me man!  Decided I am going to leave the tempering to Texas knife supply.  Still haven't figured out what to do about sheaths though.  Thinking kydex for WA wet weather and less tools for working it.  Any thoughts?  Dan

[R. Tillery]

When I forge blades from old files, I anneal them by placing them in a charcoal grill as I fire it up for burgers, then LEAVING it in the grill. Allow it to cool down slowly with the charcoal.