Want to know how to choose a folding survival knife? Check out our tips below. This is the first in a several part series that will tell you everything you need to know about choosing a survival knife. Be sure to check back later this week for more information on folding survival knives.
How to Choose the Best Folding Knife
- The ideal size is anything below 4 inches.
- Mind the blade thickness – anything above an eighth thick is good.
- Find a wide blade with flat ground.
- It must be stainless steel – durable enough to weather everyday wear and tear.
- Standard edge knives are enough. They’re easier to sharpen too.
- The blade must have a robust locking system; avoid switchblades if possible.
- The lock must be ambidextrous.
- The grip must be thin, light, and well-rounded.
In an emergency situation, a knife is often critically useful. A really good fixed blade knife is optimal for such emergency usage. However, emergencies tend to have the annoying habit of not announcing themselves in advance. Since many of us are not be able to carry a fixed blade knife under most daily conditions, having a good folding pocket knife often is a reasonable compromise for unexpected emergencies. Of course, if it is known that an emergency is likely and it is practical to do so, by all means strap on the fixed blade.
Your survival blade may be used for constructing shelter, making fire and catching/preparing food, among other uses. Although not designed specifically for combat, a knife suitable for survival uses can also be used for defense.
Requirements for a survival folder blade
Since the reason we are considering a folding knife is that it is unobtrusive and convenient to carry, the first thing to decide on is size. Having a blade less than three inches long is much less versatile for survival purposes and should be avoided unless there are valid reasons not to have a longer blade on your person (after all, a small knife is better than no knife). Although a blade longer than four inches has significant uses, such knives are usually “too big” for comfortable and unobtrusive carry, and in some locations may not even be legal to carry. If desired and appropriate, an alternative to pocket carry for a knife of this size would be a pouch on your belt.
It would seem that the “perfect” blade length for a survival pocket knife would be between three and a quarter inches and three and three quarter inches. In general, the bigger the knife is the better, up to the point where it starts to dissuade you from carrying it.
Blade thickness is also of importance. A thinner blade might be better at some tasks, and usually makes for a lighter knife, but a thicker blade is stronger, and survival usages can be fairly strenuous. About an eighth of an inch thick is a good compromise; usually a blade which is a tenth of an inch or less thick should be avoided for survival usage.
Then there is blade width. A wider blade tends to be more versatile, stronger and better for slicing, a key function of smaller knives. You get a better “belly” or the curve between point and straight edge, and a longer cutting edge for the same length of blade. Note that the cross section of the blade is also of interest. There is flat ground, where the sides of the blade are straight down to the edge (making a V), and hollow (concave) ground, where the sides of the blade curve inwards towards the edge. Flat ground is stronger; hollow ground produces a thinner edge, which has the potential to be “sharper”. Flat ground is generally superior for a survival blade.
I've heard that there are some knives which are “convex” ground; that is, the sides of the blade curve, but outwards instead of inwards. This is very strong and is often used on axes; sometimes it is called an “ax grind”. I suspect it would be good for chopping, but not so good for slicing, and as such, probably would not be the best choice for a pocket survival knife. There are other less common grinds such as saber grind, which is a flat grind which starts in the middle of the blade, and compound (double) bevel grind, which is similar to the convex grind, but easier to make.
Due to the nature of a “pocket” knife (and what tends to live in pockets), a blade of a rust resistant (stainless) steel formula is usually best. Not that a carbon steel formulation must be avoided; just be aware that it requires more maintenance to avoid it developing rust. In some cases, high carbon steel is coated to help with rust resistance.
There are many blade shapes, each with their own strengths and weaknesses and specialties. Some are particularly good for “combat” roles, but these tend to be less effective for other survival functions. Unlike for a combat or military specialty knife, a strong point is more important that a sharp point. Thus, look for a wide, single edged blade which has a thick, wide point more or less in line with the center axis of the grip. The “drop point” style blade is usually optimal, but a short, straight, “clip” blade or a “spear point” blade can be a reasonable alternative. It often would be best to avoid false or sharpened back edges, as this makes the point more fragile, which could become a problem for reliable survival usage.
Serrated edges have their uses, but are not optimal for many survival tasks. A standard (straight) edge is preferable for many survival tasks, and is easier to sharpen to boot. If you must have serrations, a “combo” blade which is standard from tip down to some of the straight edge, and then has serrations on the remainder of the blade (near the hilt) is an acceptable compromise. That is the part of the blade where serrations are often most useful anyway, although there are straight edge functions which prefer this area of the blade also…
Folding lock mechanisms
In an emergency, you want your knife to work FOR you, not AGAINST you. Having a secure method of locking the blade open is very important. Lacking this, the blade can close under stress, and guess what is in the way of it closing? Your fingers. There are two common forms of blade lock – liner lock and lockback (also known as a mainspring or spine lock). The liner lock is a spring loaded leaf which snaps in place behind the blade when it opens. This form of lock tends to be the stronger one, but it is a bit harder to close, particularly with the “off” hand, as you have to press the lock out of the way to the side as you close the blade. The lockback has a hook at the end of the mainspring, which snaps into a cutout in the blade when it opens. To close this sort of lock, press down on the back of the mainspring in order to lift the hook out of the blade notch, allowing the blade to close. These locks can be weak or fairly strong, depending on how well they are designed and made. Of course, there are a number of other lock methodologies, some of which are patented designs only available from the manufacturer or maker who holds the patent.
For a survival knife, it is best if the knife can be closed with one hand, and either hand; that is, the lock is ambidextrous. Most mainspring locks are ambidextrous, but many require you to adjust your hand to unlock them; liner locks are NOT ambidextrous by their very nature. However, a liner lock which is well designed CAN be closed with the off hand, with some practice. Generally they can be closed with the strong hand without adjusting your hand position.
The whole idea of the folding knife is that the blade is folded into the grip. In order to use the knife, the blade must be unfolded to a usable position. There are three ways to do this – manually, assisted or automatic. “Automatic” knives are commonly known as “switchblades”, where the blade is under tension, held in place by a catch. When the catch is released, the blade springs open. These should be avoided. Although it is often useful to have the knife “open itself”, automatic mechanisms tend to be less reliable and less durable than the others. Plus there is the safety concern of the catch being released in your pocket, and the legal concern, since switchblades are illegal to carry in some jurisdictions. The most reliable mechanism, as well as the one least impacted by local laws, is the manual opening one, where the blade is opened entirely by the user.
A recent advance is “assisted opening” knives. Here, the blade is NOT under spring tension, and has to be STARTED to be opened manually. Once the manual opening is started, spring tension is applied and opens the blade the rest of the way. These are a valid alternative to manual opening, and much less impacted by local laws. As long as there is an automatic or manual “safety” to prevent unintentional opening, these are almost as safe as the manual openers. Of course, it LOOKS like it might be a switchblade to the uninformed, so legal questions are still possible.
So, since manually opening the blade is likely to be required for either a manual or assisted opening knife, we want to have some “help” for that, and again, we want it to be ambidextrous. There are two common options, thumb studs, or thumb hole. There should be one thumb stud on each side of the blade, and it should be as far to the rear (close to the grip) as practical, so as not to get in the way of using the knife. The thumb hole is just that, a hole in the back of the blade. This concept, pioneered by Spyderco but now widely available, is inherently ambidextrous. Some knives have other opening systems; make sure whichever system you get works reliably and instinctually for you. Of course, you want to practice with whatever opening (and closing) system you decide on, one handed, and weak handed.
The grip should be fairly thin and light, as well as well rounded. This minimizes the outline of the knife in your pocket. It should be comfortable to hold, in all useful types of grips, and be fairly non-slip. There are some pretty good plastic-like materials out there these days. Often “liners” of metal (preferably stainless steel) provide the best strength and durability, although there are materials such as “G10” which may be adequate without steel liners.
There should be some form of topography (either an indentation or a protrusion, or at least anti-slip grooves) near the blade end, to reduce the chances that the hand will slip forward onto the blade during use, and the surface should be non-slip even when wet and dirty..
Having some grooves on the back rear of the blade allows you to guide the knife with your forefinger for some tasks and/or prevents the thumb from slipping forward. The length and location of the grooved area determines which of these functions is supported. A small notch (choil) at the end of the straight portion of the blade makes it easier to sharpen the whole blade; the alternative is to have the edge thickness smoothly transition from edge to grip, which is attractive, but makes sharpening the last bit of the blade a challenge. A large notch (finger choil) at the rear of the blade allows you to “choke up” on the blade for some tasks. Usually you have only one type of choil, as it would be unsafe to have the start of the edge with nothing between it and your finger.
There is a tradeoff between weight and durability. Generally thin reinforced nylon or equivalent grip panels over steel liners, or possibly G10 or equivalent grip panels without liners, are the best compromises.
Losing your knife during a disaster would be most unfortunate. It is important that any knife chosen have a place to attach a lanyard. Even better would be if you attach a lanyard to such a point. Here are a couple of ways to make your own lanyards from paracord:
A pocket knife can be carried loose in the pocket, or clipped to the pocket. In the latter case, a “pocket clip” is required. The best of these tend to be solid steel or titanium, screwed to the grip with at least three screws. There should be a set of matching screw holes on the opposite side, so the clip can be ambidextrous. Some knives have a rigid slot in the end into which the clip can be slid in either direction and screwed in place; this is also acceptable. There are two clip carry styles, “point up” and “point down”. Personally, I prefer point up, which means the knife is pretty much ready to open when you pull it out of the pocket. With point down, you have to swivel it into position, which is an additional opportunity to drop it. Plus, the clip has a greater chance of being in the way when opening, closing or using the knife. The pocket clip gives you additional carry options besides clipped to the pocket; in many cases, it does not prevent loose carrying, and it provides the ability to clip the knife in a waistband or belt or gear strap or molle connection. If the knife comes with a clip and you want to carry it loose, you have the option of removing the clip; storing it and its screws in case you change your mind later is wise.