The blade is the main part of the knife. The cutting and piercing properties of the knife depend on it. The main factors determining performance characteristics blade is the material and technology of its manufacture, as well as its shape and cross-section.
The blades of modern folding knives are made from corrosion-resistant types of steel. On blades famous manufacturers The steel grade is often stamped onto the blade at the base of the handle. On cheap knives you can often see the inscription on the blade - “stainless” or “rostfrei”, which simply means “stainless steel”.
Currently, the knife industry uses several dozen various brands become. Since different countries have different standards for designating steel grades, the same steel may have different designations. The most common grades of steel used for the manufacture of blades of folding knives are shown in the table. For an inexperienced user, it is enough to take into account the fact that the more expensive the steel, the longer it holds an edge, but this increases the fragility of the cutting edge and makes it more difficult to edit the knife at home.
The quality of the blade is largely influenced by the technology of thermal hardening of the steel used by the manufacturer. With proper heat treatment, even relatively cheap types of steel provide good cutting qualities of a knife, and vice versa, even expensive types of steel with flaws in heat treatment will not provide good quality blade. This is precisely the reason for the high cost of folding knives from well-known manufacturers who have modern equipment and carefully monitor the quality of the blade.
Types of blade sections
The hardness of a cutting edge is expressed in Rockwell units. Typically, folding knife blades are hardened to 42–60 HRC. The higher this number, the longer the knife holds an edge, but this comes at the cost of less resistance to impact loads and the difficulty of sharpening the knife. And, conversely, at low HRC values, the cutting edge is more ductile, easy to sharpen, but does not hold an edge well. When the hardness increases above 61 HRC, the blade of knives with a normal spine thickness becomes very fragile. Blade blades hardened to 42 units. or less, has low strength and is difficult to cut ordinary materials. This indicator is not given on the packaging of knives. Even when describing the model on the manufacturer’s website, it is not always possible to see it.
When operating a knife, it is necessary to take into account the fact that the knife blade is very sensitive to temperature increases. That is why you should not stir up the coals of a fire with a knife or use an electric sharpener for plumbing or carpentry tools to sharpen it.
The surface of the blade can be polished, matted, blued, chrome-plated or have a special protective coating.
Polishing increases the blade's resistance to corrosion, but this surface shines in the sun, which is not entirely acceptable in tactical knives.
Matting increases the anti-reflective properties, but worsens the corrosion resistance of the knife.
When bluing a blade, a thin layer protective oxide film, and the blade acquires a dark color.
When chrome plating, a thin layer of chromium is applied to the surface of the blade, which prevents corrosion of the blade, but not its cutting edge.
In modern knives, blade coating made of synthetic materials(epoxy resins, Teflon), which provide high resistance to moisture or acidic and alkaline environments. Because this coating prevents the blade from reflecting in the sun, it is often called "anti-glare" and is often used on tactical knives. The disadvantage of such coatings is low wear resistance and sensitivity to scratches.
Recently, as the industrial production of Damascus steel has become cheaper, more and more blades are being made from it. Damascus steel is produced by forge welding several layers of steel with different carbon contents. As a result, a beautiful pattern appears on the surface of the blade. Modern industrial production Damascus steel allows you to pre-design the shape of this pattern (“mosaic damascus”).
Main parts of the blade
The combination of low-carbon steel strips, which provide ductility, and high-carbon steel, which ensures the hardness of the cutting edge, allows you to create blades with excellent performance qualities. In addition, the cutting edge of Damascus steel knives has micro-teeth, which increase the cutting ability of the knife.
Knives with Damascus steel blades look very impressive. However, it should be borne in mind that the risk of receiving a defective Damascus steel blade is much higher than when purchasing a knife with a regular steel blade. This is due quite sophisticated technology production of such steel.
Doly, which are often called blood flows, are longitudinal grooves along the axis of the blade and serve to lighten the weight of the blade. At the same time, they increase the rigidity of the blade in the transverse direction. Sometimes they are through-cuts.
Ricasso- the unsharpened part of the blade at the handle serves for the convenience of sharpening the knife.
False blade came from combat knives with a fixed blade with a one-and-a-half sharpening.
Knives with reinforced edge
Folding knives use a variety of blade shapes.
For ordinary household operations, knives with a straight blade or a blade converging to the tip are preferred.
The disadvantage of the classic blade shape is its lower strength at the tip, since the thickness of the blade smoothly decreases towards the tip. Blades in the form of “tanto” or “modified tanto” are free from this drawback. At the beginning of this century, first on knives with a fixed blade, and then on folding knives, a special blade shape with a reinforced tip began to be used.
Blade shapes
If increased cutting properties are required from a knife (knives for self-defense), blades with a blade that has a convex or wavy shape are used. At the end of the last - beginning of this century, knives with a sickle-shaped blade, which is characteristic of Malaysian karambit knives, came into fashion. Such a blade does not cut, but rips up the surface of the target like a plow. Knives with such a blade are used for self-defense or for cutting car seat belts.
Knives in which the blade is located at an angle to the handle serve the same purpose. This idea received its maximum development in knives with pistol grips from STI.
Flat wedge It has high performance qualities, combining blade strength and a sharp blade. Due to the even distribution of force, it cuts well soft materials large thickness. Disadvantages - difficult to sharpen, does not cope well with cutting hard materials.
Chisel profile- differs in manufacturability and ease of sharpening. It is widespread on the blades of Asian knives. It has excellent chopping properties and cuts thin materials well.
Flat-concave wedge and its variety, a flat-concave wedge with an inlet, is characterized by ease of manufacture, is easy to straighten and sharpen, and performs excellent shallow cuts. Disadvantages - low mechanical strength, difficulties in cutting thick materials due to protruding side ribs.
Wedge profile has excellent cutting properties. The disadvantage is the fragility of the cutting edge and the difficulty of sharpening (it is necessary to sharpen the entire plane of the blade). The wedge-shaped section with inlet is free from this drawback.
Pentagonal profile combines manufacturability, strength, good cutting qualities, and is easy to straighten. Disadvantages - the difficulty of sharpening when restoring the cutting edge.
In addition to the blade, folding pocket knives may have additional auxiliary tools - an awl, a corkscrew, a can opener, a bottle opener. In the so-called “Swiss Army knives” the number of such tools can reach several dozen. Such multifunctional knives are called “multi-tools”.
Knives with additional elements
For self-defense, knives with two working blades are also produced, which allow you to hit a target with a forward or backward stroke of the hand without changing the orientation of the knife or changing its grip.
Saw (serator)
Part of the blade blade may be sharpened in the form of a saw for cutting fibrous materials. In knife literature, such sharpening is called “serator” or “serator” (from the English serrated - sawtooth). In self-defense knives, serrated sharpening makes it easier to cut through thick outer clothing and can be done along the entire length of the blade.
Various types of sawtooth sharpening (grinders)
The configuration of the teeth of this mini-saw may vary from manufacturer to manufacturer. The presence of a serrated blade makes it difficult to sharpen a blade at home - for this you need to have a special tool and skills to work with it, or contact an appropriate specialist.
Structural elements for opening the knife
The design of most modern folding knives allows you to open them with one hand, both right and left. For this purpose, there are special elements at the base of the blade - cylindrical pins, round or square shape or holes in the blade (hole round shape protected by a patent owned by the American company Spiderco, and other manufacturing companies are forced to use other forms of it). It is more convenient to open knives with protruding elements - pins or dies, but they reduce the effective length of the blade.
Structural elements for opening the blade
At the beginning of this century, knives appeared special device in the form of a hook on the butt, which ensures automatic opening of the knife when pulling it out of the trouser pocket. Owners of such knives should be aware that if the trousers are made of thin material, then after several cycles of drawing the knife they will most likely be torn.
Automatic knife opening hook
Much less common on modern knives is a special semicircular cutout on the blade. Most often it is used in models that have several working blades or tools, or in knives without fixing the blade, which are well known to the older generation from Soviet times.
Opening cutout
Another element that makes it easier to open the knife is the flipper (from the English flipper - fin) - a special protrusion on the butt of the blade. To open a regular knife, just move the blade a little, pressing the flipper with your finger, and then move the blade into the working position with an energetic swing of the hand. On the floor automatic knives There is no need for such a swing - the blade is brought to the working position automatically by a spring mechanism.
Flipper
In addition, the flipper plays the role of a kind of guard, preventing the hand from slipping onto the blade.
Design elements for more reliable knife control
The most common grip for folding knives is a straight diagonal (fencing) grip. In this grip, the thumb is located on the butt of the blade.
Thumb notch
For more comfortable control of the knife, a special notch is made at the point of contact of the thumb on the butt of the blade. The part of the handle adjacent to the blade may also have a notch.
Lever
The handles of most modern knives have a stacked design consisting of internal frame(frame) in the form of metal strips-liners (liners) and overlays. Blade fixation elements and an automatic opening mechanism (for semi-automatic and automatic knives) are mounted inside the frame.
Simple monolithic handles with a groove for the blade or handles made of a bent strip of steel are rarely found in modern knives - mainly in the French “Opitel” and African “Duk-duk”.
Monolithic handles
Previously, the parts of the handle were connected into a single whole using rivets. The axis of the blade was also riveted. IN modern models For this purpose, as a rule, screw connections are used. The use of screw connections allows you to eliminate loose parts that appear during the operation of the knife, regulate the “softness of the blade,” and facilitate disassembling the knife for maintenance work.
Most foreign folding knives use Torx screws. To work with such screws, a special tool is required - screwdrivers or socket wrenches with a corresponding head. Some companies include such keys with the knife, otherwise they have to be purchased additionally.
The shape of the handle, its cross-section, as well as the texture of the lining determine the convenience and safety of using the knife.
The rectangular cross-section of the knife is technologically advanced in production, but not convenient in execution. long work with a knife. The round handle fits comfortably in the hand, but it does not allow you to determine the orientation of the knife by touch. Therefore, oval-shaped handles are most convenient.
Shapes and sections of handles
The rectangular shape is compact, but does not provide protection against the hand slipping onto the blade. The wedge-shaped handle better protects the hand when working with the tip of the knife, but when trying to pull out a knife stuck in dense material, the hand will slide off the handle. Small pocket knives often have this shape for performing small household jobs.
The concave shape of the handle provides a more secure grip, but is not entirely comfortable. The convex shape of the handle fits perfectly in the hand and is comfortable for work. This is the shape of the handle that time-tested Finnish-type knives have.
Even more convenient is the convex-concave handle, which is often used on tactical knives.
Modern knives increasingly use handles of complex shapes that take into account the ergonomics of the hand. However, its configuration is designed for a medium-sized hand, and a person with a large or, conversely, small hand will not be able to take full advantage of its advantages.
Overlays
For their manufacture, materials of natural (wood, bone, horn) and artificial origin (metals, plastic) can be used.
The main advantage of wooden overlays is their “warmth” and the beauty of a natural material. Expensive designer knives can use exotic woods with a very beautiful texture. The main disadvantage is poor wear and moisture resistance. Multilayer varnish coating in some way solves the problem, but at the same time the reliability of holding the knife in the hand decreases.
Another natural material is horn and bone. Handles made from these materials are well polished and look very nice. Disadvantage - they can crack and scratch easily.
Metal linings are highly durable, but in the cold season, knives with such handles are inconvenient to use. In addition, they are difficult to hold in a wet or sweaty hand, even if they have a notch on them. In modern knives, titanium alloys based on aluminum or titanium are used for their manufacture. Damascus steel can also be used in expensive designer knives.
Overlay texture (top) and additional
Materials based on synthetic resins make it possible to imitate the structure of natural materials and at the same time avoid their inherent disadvantages, although they are inferior in weight. One of the most popular materials of this type is one of the types of textolite - “micarta”.
Recently, linings made from various types of plastic, such as ABC, Zitel, Kydex, etc., have been increasingly used. These materials are technologically advanced, moisture-resistant, durable and resistant to impact. external environment. They allow the production of overlays of any shape with any texture pattern - from simple roughness inherent in the overlay material itself, or rectangular notches to specially designed surface types. Thus, the knives of the CRKT “For Those Who Serve” series use a special honeycomb structure that prevents the knife from slipping in the hand.
Rubberized inserts or structural elements such as sandpaper inserts are used for the same purpose.
Lanyard holes
In the end part of the handles of many models of folding knives there is a through round hole for attaching a lanyard or lanyard to it.
Security Elements
Although modern designs of blade locks are quite reliable, nevertheless, as noted above, there is a possibility of accidental folding of the blade. To prevent this, modern knives have special fuses. For knives with a lock on the butt, they are usually located in the cutout area of the locking lever. In models with a linear lock, they are located in the front of the handle under the thumb. Supplementing the blade locks with safeties practically turns the knife from a folding knife into a knife with a fixed blade.
Fuses on knives with a lock on the butt (top) and a linear lock (bottom)
To safely carry semi-automatic and automatic knives, the safety must prevent the knife from opening in a clothing pocket if the trigger is accidentally pulled. Therefore, in such knives the fuse often has a double effect - it blocks the blade in the closed and open state.
Carrying clip
An almost obligatory attribute of modern folding knives is steel. spring clamp. In knife literature, the term “clip” is often used to designate it (from the English clip - clamp, paper clip). It ensures convenient carrying of the knife in clothing pockets or on a trouser belt.
Different types of folding knife clamps
Many knife manufacturers make the clamp adjustable - that is, it can be attached to different sides of the handle, depending on whether the owner is right-handed or left-handed. In addition, sometimes you can change not only the side of the clamp - at the base or at the end. In this case, the knife in the pocket will be oriented either with the tip down or up. Some experts believe that when carrying a knife with the tip up, there is a risk of a cut when trying to remove the knife from your pocket if, for some reason, the blade comes out of the handle. At the same time, with this orientation of the knife, it is brought into working condition more quickly.
Orientation of the blade in a clothing pocket with different positions of the clip
In some models of folding knives, the clip attachment point is not Z-shaped, but shaped like the letter “L” or “P”. In this case, when the knife is carried in a clothing pocket, the upper part of the handle is hidden from external view - only the spring plate of the clip protrudes from the pocket. Outwardly, it looks like an ordinary ballpoint pen.
Elements that enhance striking capabilities
For self-defense purposes, the knife can be used without opening the blade. In this case, it is used as a palm stick and the blow is delivered by parts of the handle protruding from the fist. In tactical and self-defense knives, the end of the handle, to increase the effectiveness of such strikes, often has a triangular shape or a special striking element in the form of a cylinder, cone or pyramid.
Impact lugs on the end of the handles
Concluding the review of folding knife designs, it should be noted that the legality of a knife, that is, the fact that it is not a bladed weapon, can only be determined by law by an expert. Therefore, when purchasing a knife, you should always ask the seller for a copy of the information sheet for the certification test report (in common parlance it is often called a “certificate”). The absence of such a document, no matter what the seller says, may indicate that the knife you like has not passed the test to be a bladed weapon. Moreover, it is best if such tests were carried out by the parent organization - the Expert Forensic Center of the Ministry of Internal Affairs. It is better to always have a copy of this document with you, which will allow you to avoid unnecessary conflicts with law enforcement officials.
Knife with copy of information sheet
Most of the high-quality folding knives on the Russian knife market are products of foreign companies.
Unfortunately, most serial domestic folding knives are inferior to foreign ones in almost all respects, and original models can rarely be found among them.
Russian craftsmen and knife companies prefer to create knives with a fixed blade, and among them there are very original models that have no analogues abroad, which include the knives of Vitaly Kim, the Kondrat knife, the NDK-17 knife (a saboteur knife designed by Kochergin) . This is largely due to the more complex technology and the expensive equipment required for it.
The original article is on the website InfoGlaz.rf Link to the article from which this copy was made -The urbanization of the modern world has led to an increase in the popularity of folding knives (in common parlance - “folders” or “folders”, from the English folder - a folded object). Such a knife is compact and convenient for a city dweller, attracts less attention, and is usually absolutely legal to carry. It can be used for a variety of operations - opening envelopes and cardboard boxes, opening plastic packaging, cutting tape, etc. In a critical situation, it can also be used as a personal defense weapon. There was even a special term for the knives of a city dweller - “everyday carry knife” or EDC knife (from the English abbreviation EDC - Every Day Carring).
The activities of human rights organizations in many countries of the world have led to the fact that folding knives have come to replace fixed-blade knives in law enforcement agencies and even in special units operating in urban environments. These knives are called “tactical”. While superior to city knives in strength and reliability, they are inferior to them in size and weight.
In addition to self-defense, they can be used for a wide variety of operations - breaking doors, breaking through office partitions and, of course, cutting ropes, etc. These knives are often used as auxiliary knives in military units, as well as tourist (camping) knives or knives for working in field conditions.
Main types of blade clamps
Achievements of modern metallurgy and inorganic chemistry, the introduction of new technologies for processing materials allows us to bring to life the most daring design ideas. Close interaction between knifemakers and hand-to-hand combat experts allows us to create original models of tactical knives with enhanced fighting qualities. As a result, new models of folding knives appear with an unusual blade shape, ergonomic handles, and additional design elements that increase the convenience and safety of using the knife.
Knives with increased cutting properties
There is no perfect knife. One or another Constructive decisions and elements increase the performance of the knife for performing certain types of work. Apart from this, there is no identical people, they have different hand sizes, they can have a leading right or left hand. For those who are not experts in the field of blades, the variety of designs creates certain difficulties when choosing a knife to suit your needs.
Design of folding knives
Folding knives have a long history and have gone from primitive designs to high-tech products, the manufacture of which uses the most advanced technologies.
A typical folding knife is a blade with a single-sided sharpening, mounted on the axis of the handle. When folded, the knife blade is hidden in the handle.
The main structural elements of a knife are the blade and the handle.
IN classic version The blade rotates in the plane of the handle. Much less common are knives in which the axis of rotation of the knife is perpendicular to the plane of the blade. Such knives look very original, but are inferior in reliability to knives of classical design. An exception to this rule is hinged knives with a transverse blade opening.
In most folding knives, when open, the blade is in line with the handle. Among folding knives designed for personal self-defense, you can find knives in which the blade can be fixed in an intermediate position - perpendicular to the handle. In this case, the knife turns into a knife with a brass knuckle grip of the type of the famous “push daggers”, which originate from the daggers of the hidden carry of card players of the Wild West. The advantage of such knives is a simplified striking technique - a blow is similar to a blow with a fist.
The STI company even developed the Tai sabaki knife (from the name of the Japanese technique of turning the body), in which the blade can be fixed in six positions, which allows you to expand the technical arsenal of striking.
STI knife with blade fixation in several positions
According to the principle of opening, knives can be divided into knives:
- with manual opening and closing of the blade;
- with semi-automatic and automatic blade opening;
- fully automatic.
In knives with semi-automatic opening, to bring the blade into working condition, it is enough to move the knife blade slightly, and then it is brought to working condition by a special spring.
Semi-automatic knives and automatic knife (right)
In knives with automatic opening, you only need to press a special button or a folding trigger guard on the handle (#4 a). In knife literature, such knives are often called “automatic” or “automatic knives,” although this is not entirely true, since the reverse operation of folding the blade is performed manually. Classic example Such knives are the “Italian stiletto” and its numerous clones.
Buttons for opening semi-automatic knives and an Italian stiletto
In fully automatic knives, both opening and closing of the knife occurs automatically. Moreover, the blade extends from the handle along the longitudinal axis of the blade (frontal ejection of the blade), and in closed position retracts completely into the handle. This allows the use of dagger-type blades with double-sided or one-and-a-half sharpening in such knives, but imposes restrictions on the width of the blade - it cannot be greater than the width of the handle.
The process of opening/closing the blade is controlled by a special slider on the handle. These knives usually have a characteristic blade play. Only specialists from the Microtek company, known high quality manufacturing of knives, it was possible to create automatic knives that are practically free of this drawback. But the price for this is their high price.
Automatic knives from Microtek
The legislation of many countries, including Russia, classifies automatic knives with a certain blade length as criminal, and their carrying in these countries is prohibited. These restrictions do not apply to semi-automatic knives.
To avoid the risk of injury if these knives are accidentally opened in a pocket, they often have a special safety lock.
The main advantage of automatic and semi-automatic knives is that they can be quickly brought into working condition with one hand. It has great importance in knife fighting, as well as for people who, as a result of their professional activities, can only operate with one hand.
The disadvantages of these knives include increased sensitivity to dirt due to the rather complex design of the opening mechanism, and therefore less reliability. Cleaning the mechanism is a rather complex procedure, especially in fully automatic knives, where it can only be carried out by qualified personnel. Therefore, automatic and semi-automatic knives are not well suited for field conditions.
Knives in which the blade opens due to its gravity (“inertial knives”) do not have these disadvantages. The most famous of them is the knife of the Wehrmacht airborne units, which is still produced in a modified version today. The knife is very reliable, has a simple design and can be easily disassembled for preventative cleaning.
Fixing the blade in open position provide special structural elements - locks (in English literature - lock). This blade fixation ensures safe use knife, especially during operations where its piercing action is necessary.
On the first primitive folding knives, the latch-lock was a special protrusion on the butt of the knife, similar to a straight razor. Currently, there are many varieties of these devices. However, only three types of locks are most widespread - back up (lock on the butt of the blade), liner lock (strip lock) and axis lock (axial lock), as well as their varieties. All of them allow you to create knives that can be opened with only one hand, and provide a fairly reliable fastening of the blade in the open position.
A type of lock on the butt of a blade
Lock on the butt of the blade(back up lock) is considered the most reliable. But knives with this type of lock are difficult to fold with one hand. In addition, there is a possibility of accidental folding of the blade when the handle is squeezed tightly.
Knives that use a type of back up lock, which was originally used on Spanish Navaja knives, are free from this drawback. A similar lock is used on the South African Okapi. In this lock-clamp, the blade is locked in the open position by the protrusion of the butt, which fits into the hole on the spring bar of the lock. To disengage the lock, just pull the special ring. IN modern versions the ring has been replaced by a more compact and convenient folding bracket - a lever.
Linear lock(liner lock) compared to the previous one, allows you to close the knife with one hand (in fairness, it should be noted that due to the asymmetry of the design, this is not entirely convenient for people with a dominant left hand). Experts believe that in terms of the reliability of fixing the blade, this lock is inferior to the lock on the butt of the blade - under strong longitudinal load, the end of the locking strip may disengage with the heel of the blade.
Much less common is the ring lock, which is used on French Opinel knives, which have been produced since the late 19th century. This lock has a very simple design - a ring with a slot. To unlock the blade, simply turn the ring so that its slot aligns with the line of the blade. The same type of lock was used on the original domestic knife “Fortel”.
In addition to the classic ones, there is a very interesting type of hinge-frame type knives. In these knives, the main design element is special frames or hinges, which simultaneously secure the blade. Such knives are characterized by high reliability of locking the blade in the open position while the knife is held in the hand. They have a symmetrical shape, making them equally convenient for both right-handed and left-handed people.
Frame knives consist of two frames, the planes of rotation of which are mutually perpendicular. Among domestic knives, these include “Chizhik” by master Konstantin Sazhin and “Skat” by the company “NOKS”.
Frame knives “Chizhik” and “Scat”
Of the hinged knives, the most famous is the Philippine balisong (butterfly knife) and its antipode, in which the plane of rotation of the blade is perpendicular to the longitudinal axis of the knife. The latter is perhaps the only knife with a transverse blade tear-off, which ensures very reliable fixation of the knife blade in the open state.
Among articulated knives, the most complex design have pantograph knives. Typical examples are the German Paratrooper knife and the Smith & Wesson Power Glide knife.
Knives with transverse blade rotation
The Paratruper knife, patented in Germany in 1938, is sometimes mistakenly called a Wehrmacht airborne knife. An indispensable condition for knives for parachutists is the ability to open it with one hand, but the Paratrooper cannot be opened with one hand. The reason for this misconception was the name of the knife, which translates as “paratrooper”. However, this name is not related to the purpose of the knife, but to the fact that its opening resembles the opening of a parachute canopy. A unique feature of this knife is that the length of the blade when open exceeds the length of the handle.
The main disadvantage of hinged frame knives is the inability to open the knife with one hand and the complexity of the design. The only knife of this type that is devoid of these shortcomings is the famous Philippine balisong knife (see “Brother”, No. 8, 2012).
Articulated knives
In most folding knives, when folded, the blade is completely hidden in the handle of the knife. Only part of the butt protrudes from the handle (for this reason, double-sided sharpening of the blade is not used in folding knives). However, there are knives in which, when folded, the blade comes out of the handle - semi-folding knives. A classic example of such a knife is the daggers of Admiral D’Estaing. This design combines the advantages of large fixed-blade knives and the small dimensions of folding knives. This design of knives was quite common on hunting and huntsman knives in the last century. It is with this knife that Kuzmich cuts a pineapple from the garden in the popular comedy “Peculiarities of the National Hunt.”
Half-mounted knives
The downside to these knives is that they require a sheath to carry them. Knives are free from them, in which the blade is retracted into a special groove that extends from the handle when the blade is folded.
The Soviet knife designed by A. I. Shilin, deputy chief designer of the Kovrov plant No. 2 named after. K. O. Kirkizha (State Union Plant No. 2). The knife was developed as part of a competition to select a folding knife for officers Soviet army, which was held in 1944, and took second place in this competition. According to some reports, a small test series of these knives was made in 1945. However, for unknown reasons, the knife never entered service. The knife had a blade with double-sided sharpening. When folded, the blade was hidden two-thirds of its length in the handle. To carry the knife, a wooden sheath was used, inside of which there were special hooks that ensured automatic extension of the blade to its full length when the knife was removed. In addition to the blade itself, the handle of the knife contained a standard set of tools necessary for Everyday life- awl, corkscrew, screwdriver, can opener and bottle opener.
Officer's knife designed by A.I. Shilin and its modern Chinese analogue
The ideas laid down by Shilin have been used in our time by the Chinese in the development special knife, which is in service with the Chinese police.
In the most simple models the blade is not locked in the open position: it will fold if you press it hard enough in the appropriate direction. This is how a classic pocket penknife works. In English literature, a knife equipped with a similar mechanism is called slip joint folder, or a folding knife with a sliding joint (more like a joint).
I could not find the corresponding Polish term. Well, okay, it doesn’t matter what it’s called scientifically; what matters is how it works. A spring, attached with one end to the upper edge of the handle, with its other end presses on the disc-shaped surface of the back of the blade. And this surface is designed in such a way that both opening and folding the knife causes the spring to bend or unbend; at the same time, it provides a certain resistance, which allows you to hold the knife either in the open or closed position (Fig. ). But if in the folded state the spring holds the blade quite reliably, then in the open position such a knife cannot be called one hundred percent safe. In practice, you have little to fear if you only use the knife for light, well-controlled cutting—for example, opening correspondence or sharpening pencils. Perhaps this is why such models are becoming a thing of the past; few of them are produced now. Even typical multifunctional pocket knives are now increasingly equipped with mechanisms that allow them to hold at least one, the largest (main) blade in the open position.
Well, to complete the review of the anatomy of folding knives, we should consider one more the most important detail, for some reason in the above article only mentioned in passing: fuse/lock. A lock is a mechanism that secures the knife blade in the “open” position and prevents it from closing spontaneously. For modern folding knives, many various designs castles, it is difficult to say which one is better - each has its own characteristics.
Liner lock
The most common type of lock, relatively simple to manufacture and yet reliable enough for most everyday tasks. The lock mechanism is based on a flat spring, which is part of the liner and rests against the shank of the blade when the knife is opened. You should pay attention to how far the spring extends onto the shank - this largely determines the reliability of the lock. This distance must be greater than the thickness of the spring itself, otherwise the knife may fold under light pressure. 
Framelock (monolock, integral lock)
A type of liner lock. The only difference is that the role of the locking plate is played by part of the knife handle, which in such cases is made of metal. This adds strength to the entire lock, because... In this case, it becomes more difficult to deform the spring. In addition, the hand holding the knife additionally presses the locking plate. 
Back lock
In castles like back lock the shank of the blade is fixed on the side of the butt by a spring-loaded rocker arm. These locks are more difficult to make due to the fact that the part of the rocker arm that engages and the slot on the shank must fit together quite precisely. Otherwise, the blade is either poorly fixed (the rocker arm does not fully fit into the shank) or wobbles (the rocker arm fits in freely). And even if they are identical, at a certain load vector there will be a slight backlash, which is due to the design itself. 
In 2008, Cold Steel refined the back lock and introduced its new creation - Tri-Ad Lock. The original design received minor modifications: a locking pin was added, which takes on almost the entire mechanical load, the geometry of the rocker arm engagement itself and the groove in the shank was redesigned, and the hole of the rocker arm axis was made oval. As a result, the strength has radically increased, and when the contacting parts wear out, the rocker will simply change its position without increasing the play of the structure. 
Compression lock
It is a hybrid of liner lock and (to some extent) back lock. The peculiarity is that the flat spring rests on the shank not from behind, as in a liner lock, but from above. Another feature is that the spring extends onto the shank on one side and rests against the locking pin on the other side. An undeniable advantage of the mechanism is that when closing the knife, not a single finger will be in the path of the blade. 
Levitator lock
Knives with locks of this type are produced by Benchmade. Due to its characteristics, the lock can only be used in knives with a metal handle. A special pattern is carved on the handle, forming a spring plate, when pressed, the rod entering the blade's shank moves and releases the blade. 
Coupling lock
Under the name Viroblock is used in most modern knives trademark Opinel. The blade is fixed using a rotating metal coupling with a longitudinal cut. In the extreme position, the clutch blocks the opening of the blade, and when the knife is in the open position, turning the clutch in any direction blocks its closure. Considering the low cost of such knives, the lock on them is simply excellent. 
Pin locks
The AXIS lock type is a patented feature of Benchmade. The blade is fixed with a spindle-shaped pin, which fits into the corresponding grooves on the shank of the knife. In this case, fixation is carried out in both the open and closed positions of the knife, which avoids accidental closing of the blade. According to the results of testing the strength of locks on budget knives by enthusiasts of the website knifelife.ru, the most durable was AXIS in the Benchmade Griptilian 551 model. The main enemy of such a lock is dirt, which can damage the knife. 
Arc lock, patented by SOG, is very similar in operating principle to AXIS, but has slight differences - the pin is additionally secured to a small rocker arm inside the handle. 
Rolling lock- another lock from Benchmade. Here the pin is completely inside the handle and is activated by an L-shaped lever with a pin extended outward. 
Ultra Lock- another type of pin lock, this time from Cold Steel. In this embodiment, the pin moves along a U-shaped groove in the blade's shank. The locking rod locks the blade at the extreme points, which ensures reliable fixation in the open and closed positions. 
Push button locks
Lock type button lock(or plunge lock) most often found on automatic knives. When pressed, a spring-loaded button-pin of variable diameter moves its thinner part into the plane of the blade and releases it. Holds the blade both open and closed. The quality of locks of this type depends entirely on the manufacturer. In general, they can be very durable, but they are afraid of dirt. 
Axial lock- a rather unusual lock, which puts most inexperienced knife lovers into a state of slight thoughtfulness. Such a knife opens and closes by pressing the knife axis and turning it with your thumb. On the axis there are protrusions that engage with grooves on the blade and in the handle. 
Stud Lock
A movable pin lock design found on Kershaw knives. When opened, a spring-loaded pin on the knife blade engages a notch in the front of the handle. To unlock the blade, you need to move the peg towards the tip. With proper skill, closing the knife is seamless and quick, and the lock guarantees proper strength. 
Deadbolt locks
Lock ram safe lock mounted on a rather unusual and recognizable Cold Steel Pocket Bushman knife. For all its technological simplicity, the lock is very powerful. In it, the shank of the blade is locked with a rod (crossbar), which moves parallel to the butt. The rod on the opposite side of the blade is pressed by a rigid spiral spring, and in order to open the knife, you need to pull the lanyard. Opening (and especially closing) with one hand is extremely difficult, but in order to break such a lock, you will have to work hard. 
Design bolt lock differs from the previous lock by the presence of a pin attached to the crossbar and located on the side surface of the handle. The principle of operation of the lock is very similar to pin designs. 
Gear lock
In design ratchet lock(or cogwheel lock) the rounded shank of the blade is made in the form of a comb with straight or slightly curved teeth, and the locking is done by a plate-plate with a slot for one tooth. When the knife is opened, the plate rises, and all the teeth of this half-gear pass through it, and in order to close the knife, it is necessary to manually lift the locking plate (most often by the ring). The lock is traditional for Spanish Navaja knives, but is also found on South African okapi (and their modern incarnation Cold Steel Kudu). 
Balisong
It is difficult to call the design of a balisong knife (popularly called a “butterfly”) a lock, but, nevertheless, we will describe this method of fixing the blade. When folded, the blade is covered with halves of the handle on both sides. When opened, each half rotates 180 degrees; in some designs they are then secured with a latch, while in others they are simply held together with one hand. 
Slip-joint
Perhaps one of the simplest types of lock, which has found its use in many budget models tourist knives. In extreme positions, the blade is held from above by the rounded shank by a flat spring. The lock does not provide rigid fixation of the blade, but nevertheless prevents the blade from accidentally folding and damaging your fingers. 
Friction fixation
So-called friction folder- the oldest design of a folding knife, the blade of which is held open due to the friction of the shank on the handle in the area of the axis. Most of these knives have a lever on the tang that protrudes from the handle when the knife is closed. By pressing it, you can remove the blade from the handle, and then open the knife by the blade. IN open knife During operation, the same lever is pressed by hand and additionally prevents folding. Well-known straight razors, European medieval peasant knives and Japanese Higonokami knives are made using this principle. 
The folding knife as we know it now appeared about three hundred years ago. It was then that a lock was invented that allowed the blade to be locked in the open state. But in fact, the history of folding knives is much older.
A short excursion into history
Folding knives have been known since the times of Ancient Rome. Then every self-respecting Roman had to carry a folding knife with him. This is due to the fact that it was considered good manners to come to a party with your own cutlery, namely, a folding knife was used for eating. It was also used as a “pocket” tool and, to some extent, a self-defense weapon. The design of these knives was extremely simple: the blade was attached to the handle on a hinge and was either hidden in the handle or removed from it with a simple turn. In the open position, the blade was held solely by the force of friction, and when cutting, by the stop of the shank on the handle. Of course, this design was primitive and short-lived; the knives often failed.
The prevalence of folding knives both in Ancient Rome and in other countries in later times is also due to the fact that carrying a large knife or dagger was punishable by law. At the same time, a folding knife was considered safe, non-threatening, and anyone could carry it. So, in the 16th century in Andalusia, in the south of Spain, Navaja folding knives appeared and became very popular. This was due to the tightening of anti-weapons legislation, which prohibited representatives of the “low class” from carrying full-fledged weapons.
Springs and locks as part of the knife design appeared at the end of the 18th century, in America, during the War for American Independence. The folding knife even became part of the field equipment of the Continental militia. The knife was also popular among the settlers, who actively used it on the farm.
At the end of the 19th century, folding knives were adopted by the Swiss army. The knife was primarily supposed to serve the Schmidt-Rubin M1889 rifle, which required a screwdriver to disassemble, as well as open canned food and perform other household functions. Such “soldier’s knives” were manufactured by Karl Elsener’s company, which later grew into the famous Victorinox.
Now folding pocket knives, which are also called folding knives, folders, are experiencing a truly “golden age”, as their popularity is growing at a tremendous pace. After all, this is an assistant for all occasions, useful in the household and safe during storage.
Design of a modern folding knife
A folding knife differs from a knife with a fixed blade primarily in that it has a movable mechanism connecting the blade to the handle. But, as with any knife, the main design elements remain the blade and the handle.
The blade of a folding knife has the same basic elements and parameters as the blade of a fixed blade knife. We wrote about this earlier in an article on. But at the same time, it also has additional structural elements associated with the need to open the knife and fix the blade in the open position.
Devices for manually opening a knife
Subdigital hole- this is a hole on the blade, usually round or oval, located closer to the handle. With its help, the folding knife is opened quickly and easily.
Pin on the blade– a special stop, for installation of which a threaded hole is drilled in the blade. The pin is screwed into it. Most knives have a one-sided peg; it can be screwed onto the desired side of the blade - under the right or left hand. There are models equipped with symmetrical pegs; they are located on both sides of the blade. This knife can be opened with both the right and left hand.
Washer- this is a peg that is located on the butt of the blade closer to the handle. It has a round or rectangular shape, with smoothed corners. Side surface washers usually have notches.
Flipper or fin– a special protrusion on the blade. When the knife is folded, the flipper protrudes above the top of the handle. When pressure is applied to the flipper, the knife partially opens. Further opening occurs either by shaking, or by using the thumb, or, if available, by an assist spring. The flipper also plays the role of a guard, preventing the palm from slipping onto the blade.
Wave- this is a hook on the butt, which, when removing the knife, clings to the edge of the pocket and thus opens the knife. Wave was invented by Ernest Emerson specifically for tactical knives, for which opening speed is an important parameter.
Notch on the blade- the oldest and most proven method of opening, which is now rare. Mainly used in models with multiple blades or additional tools. Both hands are required to open.
Sometimes manufacturers combine opening elements: for example, a wave with an under-finger notch. Or a peg and flipper, like semi-automatic knives.
It is more convenient to open knives equipped with protruding elements - a peg, a washer, a flipper, but they reduce the effective length of the blade. In addition, any protruding element may interfere with the quick removal of the knife from your pocket.
Handle
If the main requirements for the handles of non-folding knives are convenience and reliability, then the requirements for the handles of folding knives are more stringent, since their functionality is wider. The handle of a folding knife is primarily a container for the blade; it should also house the folding and locking mechanisms. Therefore, the structure of the handle is more complex, and the materials used are more durable.
The handle design of a typical folding knife looks like this. The basis for the handle of a folding knife is the internal supporting frame (frame). These are two metal plates, or liners, placed parallel to each other and connected by screws or rivets. In modern models, a screw connection is more often used. It allows you to avoid loose parts that may occur during operation of the knife, regulates the softness of the blade and facilitates the process of disassembling the knife when carrying out maintenance work.
A lock for fixing the blade and an automatic knife opening mechanism (for automatic and semi-automatic knives) are mounted inside the frame. Between the liners there is a groove in which the blade is located. The presence of the groove is provided by the rear tab, which forms the spine of the handle. When we fold the knife, almost the entire blade goes into the gap between the plates.
On the outside, the liners are decorated with linings, which can be made of either natural (wood, bone) or artificial (fiberglass, micarta, carbon) materials. The lining may be missing, and then the role of the handle is played by the frame plates, which in this case are made thicker. The overlays not only serve to decorate the handle, but also improve your grip, prevent the knife from slipping in your hand, and generally increase ease of use. The combination of the frame with overlays gives the structure the necessary rigidity and strength.
In the front part of the handle, an axis is mounted in the plates, around which the blade rotates when opening and closing the knife. There is also a blade rotation limiter when open. Between the side plates and the blade inside the groove there are also gaskets, which in expensive knives are usually made of bronze or copper, and in cheaper knives - from Teflon.
If we talk about the geometry of the handle, then in shape they can be concave, convex, rectangular, wedge-shaped, with or without grooves for fingers. In cross-section - round, oval, rectangular. The shape and cross-section of the handle determine the convenience and safety of using the knife. Their role is similar to the handles of knives with a fixed blade, as we already wrote about in the article on structure.
Security Elements
Modern models of folding knives are equipped with fairly reliable blade locks. However, the possibility of accidentally folding the knife still exists. Inadvertent opening of the knife can lead to serious injury - the blade can pierce the stomach or thigh, or injure the hand in the pocket. To prevent this from happening, many knives are additionally equipped with fuses. For knives that have a lock on the butt, the fuses are placed in the cutout area of the locking lever. For knives equipped with a linear lock, they are located in the front of the handle, under the thumb.
In semi-automatic and automatic knives, the safety locks the blade not only in the open state, but also in the closed state. After all, the trigger mechanism can also be activated accidentally when the folded knife is in the pocket.
Knives equipped with clamps are comparable in reliability to knives with a fixed blade.
Carrying clip
To conveniently carry a knife in a pocket or on a belt, almost all folding knives are equipped with a special clamp, or clip, which usually looks like a steel spring strip. It is very convenient if the clip is made adjustable - that is, it can be attached to both sides of the handle, for the right or left hand - as you wish. There are models in which you can change not only the side of the clip, but also its location - at the base of the handle or at the end. Depending on this, the knife in your pocket will be oriented with its tip either down or up.
In most cases, the clamp is attached to the handle with screws. If necessary, you can remove it and carry the knife in a sheath. There are also non-removable clamps, but such knives are quite rare.
Elements that enhance striking capabilities
A folding knife can be used without opening the blade. For example, for self-defense purposes, when the knife serves as a palm stick. The blow is delivered with parts of the handle protruding from the fist. To increase the impact efficiency in tactical knives, the end of the handle can have a triangular shape or a special striking element in the form of a cylinder, cone, or pyramid.
Additional items
Folding knives can be equipped with additional elements that expand the functionality of the knife. This could be a can opener and bottle opener, a corkscrew and an awl, pliers and a screwdriver. Their number can be from one to several dozen. Their number and configuration depend on the purpose of the knife. Thus, tourist knives, in addition to the main set of tools, can have a wood saw, fishing knives can have a sling cutter, and hunting knives are equipped with a hook for ripping the skin.
A good folding knife is a synthesis of the latest technologies and modern materials. It must have not only optimal dimensions and weight, but also reliable mechanism opening and fixing the blade. The ease of use and the speed of opening the knife depend on this, which can be important, as well as its strength and durability. Types of locks and their design are discussed in.
