Over the last few years, there has been a rapid evolution of modern electronic cards. With the advent of RFID technology, bank cards now have the ability to make contactless payments. The card no longer needs to be inserted into the terminal, but simply held against the surface of the ATM. In this case, there is a radio-frequency interaction between the chip on the card and the reader installed on the terminal. The reader generates an electromagnetic field, and the chip works as a receiver and converts electromagnetic waves into a signal. In this case, the chip does not just read the data, but also writes it. The interaction between the transmitter and receiver in this case can be made at different radio frequencies and with the use of encryption. RFID-chip itself, despite its very small size – it is a complex set of antenna, receiver and memory module. Such chips can be active or passive, and information can be recorded on them repeatedly.

In general, these are advanced ultra-modern devices that are used today in various fields. Among them are: payment systems, recognizing people at pass control, accounting for the movement of goods, data management of employees, customers and so on. The technology is very convenient primarily due to the speed of the transaction and the small size of the chips used, allowing the user to carry dozens of cards at a time.

However, there are vulnerabilities in this technology. The bank card holder’s data is stored in the chip memory and can be read at a certain distance by a specially configured scanner. In this way, an amount that does not require confirmation by password or SMS-notification can be stolen. In most banks it does not exceed 1000 rubles. Most importantly, such a theft of funds can occur from a distance of up to several tens of meters. And the victim of electronic theft will not be able to prevent it in any way.

However, the way to secure electronic cards has been known to everyone since high school physics class. The simplest and most effective way to protect against radio waves is to shield them. That is, placing the card in a case made of material that is impervious to radio signals. Such cases can be silicone, plastic, leather, wooden. The main thing is that they have a coating of special material impermeable to radio waves of different lengths. Such a case is called a cardholder, i.e. “card keeper”. In this case, the user should know that leather cardholders are the least successful choice, because with constant friction on the card, the leather acts as sandpaper. It gradually erases the protective layer of laminate, magnetic stripe and chip, shortening the life of any electronic card.

The pivoting mechanism of the sharpening device Profile K03 (professional knife sharpening machine) is a complex mechanical system that allows you to securely fix the knife, set the angle for sharpening with a maximum allowable error of 0.2 degrees and maintain symmetry when sharpening both sides of the cutting edge of the knife. The turning mechanism is adjusted and calibrated in-house and does not require any additional lubrication.

It has a wide lever that facilitates rotation and at the same time provides a secure auto-locking of the clamping frame. The swivel mechanism consists of a steel housing, swivel axle with tension wheel, auto-turn bushing and aluminum alloy frame.

The pivot axle sits inside the auto-turn bushing, which in turn sits in a steel housing and is adjusted by a tension wheel.

The pivot axle is made of hardened steel and locks the spring attached to a bar with two rolling bearings. Positioning of the axle when turning is accomplished by these bearings. It is realized by rolling the bearings into special grooves in the housing of the slewing mechanism. The housing itself is made of hardened steel grade 45. An autorotation bush is responsible for the accuracy of the bearings in the grooves. The axis of the slewing mechanism is mounted inside the slewing sleeve and runs in two rolling bearings, which allow it to rotate smoothly around its axis. There is an eccentric on the autorotation hub, which aligns the position of the hub. It is the auto-turn bush that allows the bearings to be mounted in parallel. The grooves in the housing are made horizontally, as the grinding load is also horizontal.

The spring is very durable and can work effectively for many years. Without the spring, the mechanism cannot operate. During the operation of the mechanism, it dampens the shock load caused by the frame turning over and acts as a shock absorber to avoid bearing wear during the shock. The spring of the pivoting mechanism axis is made of 65G spring steel. The bar holding the spring is spot welded to the axle.

The axle itself is housed in a steel case, with an aircraft aluminum cover. It passes through the electronic angle gauge pad. And on the frame side of the rotary mechanism, it is secured by a steel tension wheel that allows you to adjust the degree of spring tension stiffness. The tension wheel makes it possible to adjust the turning force of the pivoting frame and creates convenience for using the pivoting unit. Inside the tension wheel is another bearing, the thrust bearing, which provides clearance between the frame and the tension wheel and allows the frame to rotate, allowing the frame to rotate with the axle.

The pivot frame is made of 7075-T6 anodized aluminum and is specially pressed onto the axle. The body of the sharpener, on which the rotary mechanism is located, is made of powder-coated steel.

Mechanism elements such as: bushing and tension wheel, spring bushings and washers are zinc-coated for longer service life. The fixing screws are also chemically oxidized. Rolling ball bearings are used in the swivel mechanism.

WARNING! Disassembly of the mechanism at home is not allowed and will void the manufacturer’s warranty. Calibrating the mechanism at home is extremely difficult, without calibration the mechanism may not work properly or at all.

Galvanic bonding is a method of sputtering in which diamond particles are attached to the coated base and a layer of metal bonding is deposited from the electrolyte, covering and fixing the diamond grains. The method allows to obtain diamond-containing coatings on complex shaped surfaces and to create thin (up to 0.4 mm) diamond-containing elements and coatings.

The methods of attaching diamonds to a metal base are varied. In one embodiment, coarse grain diamond grains are first attached to the surface of the tool body, then a layer of fine grain diamond grains is applied, and the diamonds are finally infilled with electrodeposited metal. In addition, there is a technology of fixing diamond grains of different grain sizes on the tool body. In this case, the tops of the finer grains are located below the level of the tops of the larger grains. According to another technology, diamond grains of two grit sizes are deposited on the body of the insert at the same time. The efficiency of all these variants of diamond fixing, from the point of view of knife sharpening bars application, is practically the same.

The galvanic bond is in any case characterized by the fact that it holds the diamond grains only due to mechanical forces of adhesion, so the grains must be overgrown by the bond to a height of at least 65-70% of the grain size. The metal that securely holds the abrasive grain on the steel body is nickel. It provides the tool with high strength, durability and performance.

Electroplated diamond inserts provide intense metal removal and can be used for knife cutting edges that have significant damage (chips, gouges, etc). They work noticeably more aggressively than organic and metal-bonded bars with similar grain size. This is achieved due to protruding diamond grains, while in metal and organic bonds diamond grains are embedded in the binder and mixed with it. The grain size concentration in the layer is 100%.

At the same time, it should be noted that such stones will be inferior to stones on other binders in terms of the duration of work due to the thin layer of sputtering, which is actively erased in the process of sharpening. It is also important to take into account that when working with such diamonds on soft steels, hardness up to 58 HRC, this type of bars is produced faster than when working on steels with high hardness. Galvanic-bonded inserts do not require preparation for work (leveling, “cheering up”, etc.). In general, they are efficient and inexpensive solutions for fast sharpening.

Modern folding knives are a complex set of various technological solutions, an important component of which is the operation of the axle assembly. A wide variety of parts are used to ensure smooth blade travel and fast knife opening, including PTFE and metal washers, as well as ball and roller bearings.

Phosphor bronze washers

Phosphor bronze is the primary material for non-ferrous metal washers used in knife manufacturing today. It differs from ordinary bronze in that it has greater resistance to wear and abrasion forces, as well as great chemical resistance. This type of bronze is purified with phosphorus during metallurgical processing. It removes copper and tin oxides, which give the alloy hardness and brittleness, during bronze smelting. The alloy thus purified becomes hard and does not lose toughness, which makes it possible to use it in various mechanisms under impact and friction (bearings, gears, etc.). The toughness of phosphor bronze is so great that it can be forged, rolled and drawn into wire when cold. When the blade is moved to fold, these washers act as a sliding bearing. That said, they do require precision fitting when the knife is assembled in production. With regular maintenance (lubrication, grinding on polishing paste) such washers are able to work for many years.

Fluoroplastic washers

Fluoroplastic is the common name for fluorinated plastics produced by the polymerization of tetrafluoroethylene. It is synthesized as a white powder that forms lumps and is then pressed and sintered at high temperature. It can contain from one to four fluorine atoms in its composition, which is reflected in the names of the different types of this material. The most common fluoroplastics include polytetrafluoroethylene, known in Russia as fluoroplastic-4. In the USA this material is known under the trade mark Teflon. The main advantages of fluoroplastic: resistance to virtually any chemical attack, low coefficient of friction, resistance to adhesion with other surfaces. In addition, heat resistance, i.e. flexibility and elasticity of the material are maintained at temperatures ranging from -70° to +270°С. Fluoroplastic practically does not burn, in the flame it is only charred, and when removing it from an open fire completely stops and charring. PTFE products do not change their length even when exposed to temperature. As washers for knives, the main advantage of PTFE is the soft and smooth running of the blade. Like metal washers, PTFE washers require lubrication. They can deform in the axle assembly under heavy lateral loads, and the same can happen when the screw is tightened and the blade is pulled out abruptly. The washers need to be cleaned of dust and dirt on a regular basis for proper function.

Brass washers

Brass is a double or multi-component copper-based alloy where the main alloying element is zinc, sometimes with the addition of tin (less than zinc), nickel, lead, manganese, and iron. According to the metallurgical classification, bronze does not belong to bronze. The main advantages of such washers are increased wear resistance, resistance to oxidation and carbonization, they are not subject to magnetization, are not afraid of low temperatures. Brass washers are used in the Russian knife industry quite rarely, as Chinese fluoroplastic washers are more economical, and on expensive knives premium brands have already switched to the use of bearings. However, brass is often actively used in bearings for the manufacture of cages.

Bearings

A bearing is an assembly that forms part of a support or stop and supports a shaft, axle or other movable structure with a specified rigidity. It fixes the position in space, provides rotation and rolling with the least resistance, and absorbs and transfers the load from the moving assembly to other parts of the structure. Bearings can be classified into a large number of basic types: ball bearings, cylindrical roller bearings, tapered roller bearings, self-aligning double row bearings, needle bearings, thrust ball bearings, etc. Ball and roller bearings are used in folding knives. They can have either metal or ceramic balls, as well as a metal or plastic housing.

Ball metal bearings

Ball bearings are most common in knife mechanisms. They use rolling balls that roll in raceways on the surfaces of the outer rings (cages) and are encased in stamped or machined metal or synthetic (polymer) cages. Due to the point contact between the balls and the raceway, the friction torque of this type of bearings is not high, so they can develop high rotational speeds. Single-row ball thrust bearings are used to support axial loads in one direction, while double-row ball thrust bearings are used when two-sided axial forces are applied.

Kershaw’s “Kershaw Velocity Technology” (KVT for short) system is the most common in the low-cost segment of modern folding knives. KVT bearing is a seven-ball system with a cage made of polymer material, brass or steel alloy. During many years of operation, such bearings have shown good reliability and clarity of operation, despite the low cost of manufacture. The main disadvantage of this system can be called the vulnerability of the balls to the appearance of rust when the knife comes into contact with water and other liquids. Also in the application of any type of rolling bearings, the structure of the axial unit is of exceptional importance. From the shape and depth of the selection under the bearing often depends on its efficiency.

Rolling bearings

Roller bearings are essentially the same design as the ball versions. That is, a metal or plastic cage in which metal cylinders are recessed. They rotate around their axis, developing speed in one direction. Usually such bearings are single-row, and do not form complex multi-row systems. They run at the same speed as ball bearings, require lubrication and also have poor side load tolerance.

Ceramic Bearings

Ceramic bearings are the most advanced device for folding knife assemblies. The basic material for these products is usually silicon nitride (Si3N4). Due to the fact that this type of ceramic has outstanding impact strength and high rigidity, this black, shiny after polishing material has been used extensively in recent decades in mechanical engineering. These bearings are usually mixed (hybrid) bearings – only the balls (or other body of rotation) are made of ceramic and both rings of rotation are made of steel. The cage on hybrid ceramic bearings can be made of either synthetic materials or iron.

The main advantages of ceramics are: the ability to work in aggressive acids and alkalis without corrosion, ceramics are up to 40% lighter than steel and are much better at dissipating heat. The Rockwell hardness of steel balls rarely exceeds 60 on the HRC scale, while ceramics can be as hard as 75. Since ceramics is harder than steel, it has a higher modulus of elasticity. This is the most important advantage. This means that the balls deform less when loaded and rotated.

Knives today utilize a wide variety of ceramic bearing systems. From the simplest single row, to complex three and even five row systems with bronze cages, on a steel cage backing and a PTFE dust ring. Ceramic bearings require a high degree of hardness of the blade dies in which they move, as a soft steel bearing will produce metal. Which in turn will lead to backlash in the axial assembly. This can be especially true for a titanium handle with grooves without a steel backing. If these bearings will be in specially cut grooves with steel of high hardness, there will be so-called nagartovka – hardening of metals and alloys due to changes in their structure and phase composition in the process of plastic deformation. In other words, the metal in this place will be hardened. To lubricate ceramic bearings, a special Teflon-based grease is required. This is due to the fact that when using oil or any thick grease in the axial unit will accumulate dirt, which in contact with the bearing will work as an abrasive and lead to the same development of metal.

IKBS bearings

Developed in 2002 by brothers Lala and Flavio Ikoma from Brazil, the IKBS system is designed to open and close a folding knife easily and quickly. The Ikoma Korth Bearing System (that’s how IKBS stands for IKBS) uses ball bearings to provide a smooth opening action that is many times faster than its counterparts.

To use IKBS, a countersink is made in each side of the liner and the balls are placed there. The blade does not rest on the planes of the washers, but only on the ball bearings at the points where they contact the countersinks in the liners. Thus, only the balls and grooves in the liners remain from the bearing design, which makes the whole mechanism easier and simpler and more reliable. The heel of the blade is not modified. IKBS is best used on knives with Frame-lock and Liner-lock. It is the simplicity of the design that makes the IKBS system reliable in practice.

The size and number of balls required by the IKBS for proper operation is determined by the size and purpose of the knife. The IKBS takes up very little space in the overall knife design, allowing it to be used in almost any folding knife, even balisongs (“butterfly”). The type of balls can range from simple carbon steel balls to very expensive ceramic balls. Compared to the traditional washer system, IKBS stands out for its much lower friction between the blade and the liner. It is one of the most efficient and reliable bearing positioning systems on a folding knife today. It is used by dozens of knife manufacturers around the world.