In a survival situation, a knife can be one of your most important tools. It’s a weapon and an eating utensil. You can cut rope with it. You can dig with it. You can peel bark from a tree to use as fire fuel. You can skin an animal with it. It’s a very verstile tool that can come in handy in any number of situations. You should keep one in your Go Bag, but for some reason or another, if you lose that knife I’m going to show you how to manufacture a field expedient knife to use until you can get your hands on a new knife or can forge yourself a new one.
First of all, a knife performs three basic functions: piercing, slashing, and cutting. Ideally, a knife will do all three, but in some cases a field expedient knife will only ever be able to do one or two. You can fashion a knife out of all sorts of material: metal, wood, stone, bone, glass, plastic… It all depends on what you have available.
Your obvious first choice for a knife material, metal is going to probably be scarce and especially metal that is small and thin enough to be used as a knife. However, if you’re lucky enough to stumble on a piece you will be able to fashion a knife that will last you a very long time and that you can resharpen.
If you don’t have tools to work on it, most metal is nearly impossible to manipulate. So if you can’t find a piece that is pretty close to what you want you might not be able to make a knife. You can try hammering the piece into the shape you want, but this will only work on soft metals.
Once the rough knife is in the general shape you want, you need to sharpen the edge. This can be accomplished by running the edge across any rough surfaced stone (including pavement). You will get a better effect if you get the stone wet before attempting to sharpen it.
If you want to get a REALLY sharp edge, rub the edge of your knife on unpolished ceramic. If you look at the bottom of a coffee cup, you’ll notice that rough ring that the cup sits on. That ring is unpolished ceramic and will even sharpen forged knives, including the knives you have in your kitchen right now. Yes, this tip applies to non-survival scenarios too!
Stone is one of the most reliable and sturdy materials to make a knife from. Since its such a sturdy material, you will need a couple of specialty tools to make the knife:
- Chipping Tool – a chipping tool is a blunt tool used to break off pieces of stone
- Flaking Tool – a flaking tool is pointed to break off flat pieces from the stone
The first consideration you need to make is the actual stone you will make into a knife. You need to use a soft enough stone that you’ll be able to carve it with your tools. Secondly, it’s totally up to you how long you want the blade, but you need to account for a handle or a tang to attach a handle. If you can find a rock that’s already close to the shape of a knife you;re in business. If worse comes to worst, you can use your chipping tool on the edge of a boulder and try to knock a piece loose to make a knife from.
Get the general shape of your knife using the chipping tool. Strike your soon-to-be knife with one end of the chipping tool repeatedly until the knife holds the desired shape. Try to keep your knife relatively thin – the thinner it is, the easier to get a sharp edge. However, don’t get it too thin or else you run the risk of the knife breaking under stress.
The flaking tool requires a little more finesse. PLace the flaking tool against the knife near the edge and apply pressure until pieces break off from the knife. Don’t press too hard, or you could end up break off a chunk of your knife that you didn’t want to lose and it won’t have a sharp edge to it. Continue doing this down the length of one, or both, sides of the knife until you have a blade edge. Make sure to leave enough unsharpened length to be the handle or tang.
If you choose, you can attach a seperate handle to your knife. Just tie a piece of wood or some other material to the base of the knife. Make sure to secure it tightly or else you’ll have problems with the handle coming loose later (which could in turn cause injury).
Bone is a step up from wood, but it isn’t going to be as easy to find. So given the choice between the two, go for bone. Your first consideration is the size of the bone. If it’s too small, you won’t be able to make a knife out of it. To make a knife out of bone, you’re going to shatter the bone so a larger bone is going to create more shards. Once you’ve found a suitable bone, place it on a hard surface and smash it with something heavy like a rock. Go through the shards and find one appropriately pointy with the potential for a sharp edge. Sharpen the edge of your shard against a rough surface (like cement). Don’t forget to leave a portion unsharpened as a handle or tang to attach a handle.
Wood is easily the most abundant resource you will find in most of the world. Unfortunately, it doesn’t make for an ideal knife-making material. If you make a knife from wood, you will only be able to use it to puncture things and the point will go dull fairly quickly at that. If you look at a piece of wood, you can see the grain is either straight or in a circle. The straighter the grain, the further from the core of the branch/tree the piece is. If there is no grain, it means the piece of wood is from the pith (the layer of wood seperating the tree from the bark). You want to avoid wood that is from the core of the tree/branch and you want to avoid pith. Both types of wood are weak and will crumble or snap if used as a knife. Select a piece that’s roughly a foot long and shave the tip down to a point using a rough surface (like cement). Once you’ve sharpened the point to the desired point, place the blade over a fire and let it slowly dry until it is lightly charred. This process is known as “fire hardening” and will make the point hard and it will take longer to dull.
Fashioning a blade out of bamboo is very similar to wood. However, bamboo is capable of holding an edge. When shaping the knife, remember that the hardest part of bamboo is the out shell so try to keep as much of this layer as possible. When fire hardening bamboo, only char the inside
When glass is broken, it naturally make a sharp edge so it is ideally suited as a knife. Unfortunately, glass is incredibly brittle so you can’t use it for heavy duty work. All you need to do for a handle is wrap a piece of cloth around the base of the shard.
The ceramic used to make coffee cups is similar to glass so in a pinch you can break a coffee cup and use the piece attached to the handle as a knife.
Have you ever stabbed yourself while trying to open up a new piece of electronics? If not, you’re lucky but if so you are painfully aware of how effective plastic can be as a knife. You can also sharpen plastic—if it is thick enough or hard enough—into a durable point for puncturing.