How to make a survival knife from an old file

A survival knife that can cut a gouge out of other “survival knives”.  How you can make one.

 

Holy second mortgage, Batman!  Have you seen the price of a decent knife?   If you have, you were no doubt as dumbfounded as I was.  Also, it seems that in this age survival this and tactical everything (seriously you can buy tactical t-shirts….. do they even do anything?) people have forgotten what makes a good knife…. a good knife.

If you just want to learn how to make the knife, feel free to skip the following paragraph. 

 A knife is a tool, not a fashion accessory.  All these whirly barbs and flowing spikes are just that, fashion accessories designed to attract adolescent boys from the ages of 5 to about 50.  (Guys, it’s a knife not growth hormones for your penis… it’s going to stay that size forever….. I’m sorry).  Moreover, these Rambo spikes get in the way of any real work.  A knife is also not a flashlight, nor is it a cell phone.  I have a flashlight and a cell phone, and they will be safely out of the way while I use my knife to cut, slash, stab, pry, or chop whatever the job requires, thus preserved until such time as I need them.  Don’t get me wrong.  A good multi-tool is a must.  I carry one everywhere I go.  But for those jobs that require a fixed blade knife, I need a good knife, not a techno-trinket.  The two stupidest features ever to grace a “survival knife” are: 1) the “tactical impact device”.  (Ok guys, love the name, but it’s a butt spike.  That’s all it is.  Just call it a butt spike.)  What this means is that if I need to grab the back of my knife for leverage, control, or to push the blade into something, I can’t.  At least, not without hurting myself.  (Wait, my logic is tingling.  If I needed to use the “tactical impact device” on my knife to defend myself, wouldn’t logic dictate I would … I don’t know, stab them with the knife it’s attached to instead?) But that’s not even the worst knife accessory.  That honor goes to the knives with the: 2) “storage compartment” handle.  First off, the handle.  These are of the poorest ergonomic shape possible, and offer so little “storage” that you’ll be hard pressed to find anything to fit in it.  But these troubles really matter little, seeing as a hollow handle means that the knife has no tang (the piece of blade that extends into the handle) and thus will break almost immediately upon all but the lightest use.

Now, to make the knife.

First, you are going to need is an old file, preferably one that is worn out but of good quality, not to much rust and was, at one point, a good file.  Cheap files are often simply casehardened steel.  The steel on the outsides of the file are hard but the inner portions of the steel are soft. These are better than nothing, but not awesome by any stretch.  The better the file, the better the knife.

As it is now, your file is too hard to be worked.  Don’t try.  You’ll ruin your tools.  It needs to be softened first.  This called annealing.  To do this, you will need to heat the metal until it glows a yellow-orange color, then allow it to cool slowly.  You can do this with a torch, kiln, or forge.  I’ve even been told you can, with some time and effort, use a gas or electric cook top by placing the file directly on it moving it periodically to keep the heat even.  But you could do it the easy way.  Build a fire pit and get the fire good and hot, then place the file in the hot coals.  Then roast hotdogs, make smores and have a grand time with your friends and family… unless you don’t like your friends and family.  If that’s the case, get drunk stare in to the flames and contemplate your life.  Come back tomorrow morning, after the fire has burned out and the ashes cooled (and you are no longer drunk and sobbing), to retrieve your now annealed file.

 

With your file now soft enough to be worked, use a hacksaw to cut the rough shape of the knife you want out of the file.  But first, I suggest you really think about what you need in a knife.  What will you be using it for?  Which will you spend more time doing, chopping tree limbs or cutting string?  Maybe you are a hunter and need a more rounded tip for skinning game.  Or maybe you are a ninja and need a pointy stabby tip to assassinate sleeping samurai.  The point is, now is the time to decide what you need and want in a knife.  Now is the time to make it your own.

Rat tail tangs are the most common type of tang.  They are not as strong as a full tang, but are easier and allow you to make your blade longer.

Full tangs are the strongest type of tang.  Also, these tend to have the best balance.  But it means your blade must be shorter if you are using a file, and they are a bit of a pain in the ass to make.

Tanto tips look like the tip of a katana (samurai sword) and are by far the easiest to make, as once you make your rough cut you don’t need to shape it with a file.  (Also according to some, because it looks like “a ninja sword” it must cut like one and will therefore cut through the engine of an old Chevy truck without losing its edge.  But don’t get me started on the “ninja sword” fan boys.)

Drop point tips are where the edge curves gently up to meet the tip.  One of the oldest tip styles, the curved edge is great for skinning and other delicate tasks while still offering a nice sharp point.  It’s harder to make, but in my opinion, well worth it.

Other tips, whatever you want to do, do it.  Just don’t complain to me if your knife ends up sucking because of it.

Once you have the rough shape cut out, use a file, stone, or grinder to remove the file grooves.  Then file the knife into the desired final shape.  If you need to drill any holes, now is the time to do it.

Ah, and now for the part the sucks, grinding your edge.  If you have a powered grinder, it won’t be so bad.  If you don’t, well, you know what they say no pain no …. aw screw it.  I’ll finish it tomorrow.  Believe me, I have made knives like this with a wet stone and it’s still worth it.

Holding the file at about a 15 degree angle, start putting an edge on your knife.  I find it works best to work a little on one side, then flip it over and work on the other.  That way you meet in the middle, whereas if you work on one side more than the other, the edge ends up being off center.  But remember, you are just building an edge, not sharpening, so the minute you meet in the middle, stop.  It’s too soft to sharpen right now.  We’ll do that later.

Now, time to harden your knife.  You can rebuild your fire for this one, but I suggest burning oak and or charcoal as this fire needs to be hot as hell.  Lay your knife in the coals and heat it up to a nice bright yellow-orange.  Once it reaches that color, use tongs and gloves to pull the blade from the fire and check it with a magnet.  If the magnet sticks, it’s not hot enough.  If it doesn’t, quickly but evenly dip the knife into a bucket of used motor oil and let it cool.  Once it has cooled enough that the metal is black (and not flaming), you can drop it into the oil to cool the rest of the way. Be sure to use a metal bucket for your oil.

If you have trouble getting the knife hot enough, bury a steel pipe under the coals, hook an inflatable mattress pump to the other end and pump air through the pipe.  Also, you might need to hill dirt up around your fire.  Laying a sheet of metal over the coals helps keep the heat in, but don’t cover it completely.

With your knife now hardened, use a fine grit metal sandpaper to clean and smooth out your knife.  Get it all polished and pretty.  Remember, chicks hate an ugly knife.  Once that is done, use the sharpener of your choice and, you guessed it, sharpen your knife.

Tempering “YEAH YEAH COOL COOL FIRE FIRE FIRE HA HA HA HA HA!  You can use a butane lighter, but a torch works better.  Heat along the back of the knife, moving the flame often to heat the metal evenly. Heat the knife to a dull straw color, then allow to cool.

Time to put a handle on your knife.  You can use any wood, antler, bone, plastic whatever you want.

For a rat tail tang drill a hole a little deeper than the length of your tang and a little smaller than the width in your handle.  Drive the handle on the tang.  Then shape your handle however you choose.

For a full tang cut two plates of wood slightly bigger than your handle needs to be.  Drill two holes in each plate that line up with the holes in your tang.  You can bolt or rivet the plates to your knife.  Riveting seems to work better.  Then, take a file and or sand paper and sand the plates until they meet smoothly with the steel.

Uh…. Ta da.  If you followed my instructions, you now have a knife that can cut a 1/8 inch gouge in the blade of most other “survival knives”.  Mine can.  But I don’t suggest trying it as it will dull your blade.  Two things to remember about your new knife: one, it will be harder to sharpen than most other knives, but also sharper and harder to dull; secondly, this is not stainless steel so you will actually have to take care of it.  (Gasps!)  So keep the blade oiled and remember, if you take care of it, it will take care of you.

Files are a good choice for a knife because they are made from good high carbon steel.  However, don’t overlook things like mower blades and worn out hand saws. Most any cutting tool can gain a second life as a good knife.