In a survival scenario, a knife is by far your most important tool. A knife has four basic functions. It can puncture, slash or chop, cut, and scrape. A knife is also an invaluable tool used to construct other survival items. If you find yourself in a survival situation without a knife, you can make a homemade knife using stone, bone, wood, or metal to make a knife or spear blade.
As a utility, a knife can take many forms.
Hunting knives are typically used to dress large game. They are designed for skinning the animal and cutting up the meat. They are typically made for cutting rather than stabbing and feature a single sharpened edge. Most have slightly curved edges, and some incorporate a “gut hook” in the blade design. They are based on a smaller version of the Bowie knife.
Some are designed to be adapted to other uses in the wild, much like a survival knife, and may be used as hatchets or machetes when those tools are not immediately available.
Survival knives are typically sturdy and built for a wider assortment of tasks and are made for survival purposes in the wilderness. Most military units issue survival knives to their soldiers. They can be used for building traps, skinning, wood cutting, defense, and other purposes.
Most survival knives have a full tang with a spine (back of the blade) that is flat allowing it to be used as a hammer-type tool (some have serrated spines). Handle materials vary widely and can include rubber, bone, wood, aluminum, polymer, or metal. Manufacturers of survival knives include Ka-Bar, SOG Knife, Gerber, and Mora.
Tactical knives are typically built to act more as a weapon than a tool but still retain tool-like features as military proponents have worked to evolve the fighting knife to include more features designed for use in extreme situations. In addition to fighting, tactical knives are designed to facilitate cutting rope, strapping, harnesses, rigging, and a variety of other tasks.
Many tactical knives implement folding designs even though opponents point out that in a defensive situation, the time to unfold a folding tactical knife is not practical. Most tactical knives still utilize fixed blades.
Bowie knives are large sheath knives with a pattern first popularized by legendary Jim Bowie in the early 19th Century. It was originally designed to be a short sword that still possessed a heavy blade. Featuring a cleaver-like blade, it is designed to be heavy enough to give the blade sufficient force in a slashing attack while still permitting the use of cut-and-thrust sword fighting tactics. Most Bowie knives have blades of at least 8 inches in length with broad blades between 1-2 inches wide. Bowie knives have a clip point that brings the blade lower than the spine. Often the curved top clip bevel of the blade is sharpened making it ideal for skinning. “It must be long enough to use as a sword, sharp enough to use as a razor, wide enough to use as a paddle, and heavy enough to use as a hatchet.”
The machete is a large, cleaver-like knife with a long thin blade and a convex or flat bevel from the spine to the edge. The name is Spanish meaning “little sledgehammer”. Machete blades are long and thin, typically 12-24 inches long and under 1/10 of an inch thick. Machetes are excellent tools for cutting through brush. Construction is usually very simple even though the blades are designed for strength and toughness (many are tempered to achieve maximum toughness).
A multi-tool knife combines several functions in a single tool. The original Swiss Army knife (manufactured by Victorinox and Wenger) supplied to the Swiss Army includes a knife blade, reamer, bottle opener, screwdriver, wire stripper, and can opener. Other tools included in some multi-tool knives include tweezers, nail file, scissors, toothpick, magnifying glass, screwdriver bits, allen keys, wrenches, spoke keys, needle nose pliers, and chain breakers.
A knife consists of several components.
The tang of a knife is the part of the knife blade that extends into the handle. The best knives have “full tangs” that extend all the way to the base of the handle. Full tang construction adds strength to the knife making it very difficult to break the knife.
The handle of the knife can vary in construction. Wood, rubber, polymer, or leather-bound handles are common. Two things to avoid in knife handle construction is survival knives that have hollow handles to store survival gear such as matches or fishing gear. If a knife has a hollow handle, it does not have a full tang which means it is prone to break. Another component to avoid in the handle is a compass. Some survival knives feature compasses embedded in the butt of the handle. They are typically cheap and affect the quality of the handle construction.
The bottom of the knife handle, called the rear bolster or rear quillon, may be curved to improve the grip and the top of the knife handle, the front bolster or front quillon where the handle meets the blade, may have a perpendicular piece that protects the fingers.
The choice of blade material often attempts to balance the need for sharpness with the need for a long-lasting edge on the blade and no matter what the material, various methods are used to harden the blade so it will take a sharper edge and maintain that sharpened edge for as long as possible. Some metals, like copper and bronze, can be hardened by striking the blade with a hammer while it is cold. Materials such as carbon steel can be hardened by quenching it with water after it has been heated to a critical point. A blade made from steel may also be tempered by heating it at a relatively low temperature for a long period of time.
Modern-day knife blades are usually constructed of steel or carbon. Stainless steel blades are virtually indestructible and will not rust. However, they lose the sharpness of their edge easier than carbon blades. Carbon blades hold their edge longer but will rust easier than Stainless Steel.
Knife blades are typically straight or serrated. The ability of a knife to cut arises from the concentration of force applied to the blade concentrated into a small area, the sharpened edge, resulting in high pressure on the matter to be penetrated. A straight blade is better for chopping and is easier to sharpen. A serrated blade takes the physics principle even further by concentrating the force onto an even smaller area. Serrated blades are best for sawing and require a special blade sharpener to sharpen.
Blade Shape (Profile or Pattern)
Knife blades can vary in shape with each profile, or pattern, offering different benefits to the knife user.
Normal or Straight Back Blade
As the name implies, the “straight back” blade features a dull back that is straight. The added thickness makes the blade strong and heavy. They are all-purpose type blades good for chopping, picking, or slicing.
Trailing Point Blade
A “trailing point” blade has a spine (the unsharpened, top of the blade) that curves upward. Trailing point blades are great for detail work such as skinning animals but are more difficult to sheath. Due to the design, the point of the knife is weaker than a straight-edged knife blade.
Tanto Point Blade
A “tanto point” blade has a tip angle that is less acute and hence contains more metal. This strengthens the tip giving it one of the strongest points possible in a knife blade. The tanto point design effectively provides the knife with two blade edges. Tanto blades are popular combat or rescue knives.
Clipped Point Blade
A clipped point (or slant point) blade has an increased point angle that curves towards the sharpened edge making the tip of the knife narrower. The curve usually begins sharply, hence the name “clipped”. Some clipped point blades may have both edges sharpened. Many Bowie blade knives have clipped point blades.
Drop Point Blade
Similar to a clipped point blade but with a slightly curving edge on the top. This is the most popular blade design and makes the knife very easy to sheath.
Spear Point Blade
Spear Point blades have an almost uniform profile of the point. Both edges curve towards each other with a point that meets in the middle. They are often doubled-edged blades.
Needle Point Blade
A needle point blade is a very sharply tapered blade. Frequently found on thrusting-type blades, the long, slender point reduces friction and increases the blade’s penetrative capabilities. The narrow blade design makes the tip prone to breakage and often needle point blades are reinforced to lessen the chance of breakage.
Spey Point Blade
A spey point blade has a single, sharp, straight edge that curves strongly upwards at the end to meet a short, dull, straight point from the dull back. Spey blades used to be popular for skinning fur-bearing animals. The somewhat blunt tape makes penetration more difficult.
A sheepsfoot blade has a straight edge and a straight dull back that curves towards the edge at the end. It gives the most control because the dull back edge is made to be held by fingers.
A Wharncliffe blade is similar in profile to a sheep’s foot, but the curve of the back edge starts closer to the handle and is more gradual. Its blade is much thicker than a knife of comparable size.
Making A Knife in a Survival Situation
A stone knife may be constructed in the wild if a regular knife is not available. Stone knives are inherently more brittle than metal knives and cannot be used to pry and lever the way you would with a metal knife. They also break easily when dropped. Stone knives should only be used to slice.
To make a stone knife, you will need a sharp-edged piece of stone, a chipping tool, and a flaking tool. The process of chipping and flaking stone to make a blade is called flintknapping.
The best rock material is solid rock with no visible cracks. Fossil-laden rocks or porous rocks are too brittle to use for a stone knife blade. You can look for a suitable stone or use a large hammering rock to chip a piece of stone off of a larger rock. If you use a hammering rock to chip a blade blank, watch for flying chips. Try to find a stone or piece of stone that is roughly the shape of a knife blade.
You will need a “chipping tool” to form the knife blade. A chipping tool is a light, blunt-edged tool used to break off small pieces of stone. A flaking tool is a pointed tool used to break off thin, flattened pieces of stone. The best material for chipping and flaking tools are flint, chert, or volcanic glass but you can make a chipping tool from wood, bone, or metal, and a flaking tool from bone, antler tines, or soft iron.
Start making the knife by roughing out the desired shape on your sharp piece of stone, using the chipping tool. Use glancing blows near the edge to get the edge thin enough to sharpen and try to make the blade fairly thin. When chipping, watch for chips produced that could be useful as arrowheads or smaller cutting instruments.
After chipping out the rough shape of the blade, press the flaking tool against the edges. This action will cause flakes to come off the opposite side of the edge, leaving a razor-sharp edge. Use the flaking tool along the entire length of the edge you need to sharpen. Eventually, you will have a very, sharp cutting edge that you can use as a knife.
Next, cut grooves near the butt end of the blade.
Finally, lash the blade to some type of hilt (hardwood, antler). You can also shape a handle from wood or bone with a notch that is wide enough to accept the stone blade. Slip the stone blade into the notch and lash it tightly.
NOTE: Stone will make an excellent puncturing tool and a good chopping tool but will not hold a fine edge. Some stones such as chert or flint can have very fine edges.
You can also use bone as an effective field-expedient-edged weapon. They are best for puncturing as they do not hold their edge well (and may flake or break if used for cutting). First, you will need to select a suitable bone. Larger bones, such as the leg bone of a deer or another medium-sized animal, are best. Bones should be cleaned and disinfected before handling.
Lay the bone upon another hard object. Shatter the bone by hitting it with a heavy object, such as a rock. From the pieces, select a suitable pointed splinter to use as your blade. Shape and sharpen this splinter by rubbing it on a rough-surfaced rock or carving with a normal knife. If the piece is too small to handle, you can still use it by adding a handle to it. Select a suitable piece of hardwood for a handle, cut a slit into the top of the handle, and work the bone into the handle. Lash the bone splinter securely to the handle.
You can make field-expedient-edged weapons from wood. Since wood knives will not hold their edge well, use these only to puncture. Bamboo is the only wood that will hold a suitable edge.
To make a knife from wood, first select a straight-grained piece of hardwood that is about 30 centimeters (12 inches) long and 2.5 centimeters (1 inch) in diameter. Fashion the blade about 15 centimeters (6 inches) long. Shave it down to a point. Use only the straight-grained portions of the wood. Do not use the core or pith, as it would make a weak point.
Harden the point by a process known as fire hardening. If a fire is possible, dry the blade portion over the fire slowly until lightly charred. The drier the wood, the harder the point. After lightly charring the blade portion, sharpen it on a coarse stone. If using bamboo and after fashioning the blade, remove any other wood to make the blade thinner from the inside portion of the bamboo. Removal is done this way because bamboo’s hardest part is its outer layer. Keep as much of this layer as possible to ensure the hardest blade possible. When charring bamboo over a fire, char only the inside wood; do not char the
Metal is the best material to make field-expedient-edged weapons. Metal, when properly designed, can fulfill a knife’s three uses – puncture, slice or chop, and cut.
First, select a suitable piece of metal, one that most resembles the desired end product. Depending on the size and original shape, you can obtain a point and cutting edge by rubbing the metal on a rough-surfaced stone. If the metal is soft enough, you can hammer out one edge while the metal is cold. Use a suitable flat, hard surface as an anvil and a smaller, harder object of stone or metal as a hammer to hammer out the edge. Make a knife handle from wood, bone, or other material that will protect your hand.
Other Knife Materials
You can use other materials to produce edged weapons. Glass is a good alternative to an edged weapon or tool if no other material is available. Obtain a suitable piece in the same manner as described for bone. Glass has a natural edge but is less durable for heavy work. You can also sharpen plastic—if it is thick enough or hard enough—into a durable point for puncturing.