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.

Historically, the earliest versions of handles were wood overlays. The classic folding knives, the Spanish Navajas and French Opinels, had handles made of walnut, beech, oak, and other commonly available woods.

Handles made of horn and bone, as the hardest, most durable and wear-resistant materials, were the most reliable in the period before the advent of plastic and composite materials. Deer horn, elk horn, ivory, mammoth tusk, buffalo horn, stabilized mammoth tooth, and walrus tusk were all used. All of these material options were usually used as spacers in the metal cheeks of the hilt.

Today, only a small number of manufacturers have an all-wood handle left. Nowadays, the handle of a folding knife is an opportunity for a manufacturer to realize high-tech ideas in a wide variety of variants.

Among the modern and most common materials for folding knife handles are:

Metal handles

Metal handles are made mostly of aircraft-grade aluminum, titanium and steel.

Aviation aluminum is a metal alloy in which the alloying elements are: copper (4.5%), magnesium (1.6%) and manganese (0.7%). In the knife industry, it is mainly used in the 6061 alloy variant (6061 T-6 Aluminum). This alloy is corrosion resistant, lightweight and strong enough for a knife used for urban carry and low loads.

Titanium is a lightweight and strong material with a silvery white color. Titanium is a completely non-magnetic material. Knives are often used in quite aggressive conditions and do not rust at all. Titanium is significantly lighter than steel. Handles made of titanium are well anodized and take any color. All these qualities make it one of the most sought-after materials for expensive, premium knives. But it also has a distinct disadvantage – softness and rapid wear when interacting with steel. This necessitates the use of a special steel pad, the so-called “dryer”, on knives with a titanium frame-lock. Without it, the titanium locks on the handle often jam in the open state, which makes it impossible to use the knife properly.

Steel – Knife handles either use the same steel as the blade (this applies to the cheapest knives), or use a significantly cheaper and softer steel than the blade. The most commonly used steel for knife handles is 420 J2 steel, which is used by most of the well-known American companies. The main quality of steel for handles is corrosion resistance.

Composite handles

Micarta (fiberglass textolite) is a composite material consisting of fabric (most often cotton, canvas or linen fabric, occasionally paper) and a special synthetic resin adhesive. Such a composite allows you to create a handle of any color, with a beautiful, most fanciful pattern. Mikarta does not absorb odors, does not allow water to pass through. However, it has a noticeable disadvantage – when cracked or chipped, it begins to chip out at the point of damage, the thread begins to delaminate and fall out of the structure.

Glass Fiberglass Textolite G10 is a composite material that contains fiberglass cloth and epoxy resins. The process of production of the material is soaking glass fiber in resins, after which the impregnated glass fiber is subjected to compression. The result is a material that performs well under adverse conditions. G10 is a strong and impact-resistant material, perfectly tolerates moisture and can be colored (including layer-by-layer). This fiberglass textolite looks very similar to micarta, but is characterized by increased resistance to fire and higher strength. The main disadvantage of G-10 is that the handle becomes slippery and uncontrollable in a wet or greasy hand.

Dymondwood (Dymondwood) is the name of a composite material (laminated plastic). Its main components are wood, which serves as a base and phenolic resin, which is impregnated with wood. In the domestic market there is an analog of laminated plastic, – “delta-wood”. In the manufacture of Dymondwood natural wood is thoroughly dried, after which the voids are filled with polymer, which is able to quickly harden. Thus, the wood turns into a plastic-like material that does not deform, is strong enough, does not interact with water and is aesthetically appealing. Such a handle is not subject to corrosion, does not absorb odor and is quite cheap in production. The main disadvantage of this material is its weight, it is approximately one and a half times the weight of the original wood.

PaperStone (PaperStone) is essentially an analog of Bakelite, which is a material that contains cardboard (or paper) and phenol-formaldehyde resin. Extremely tough material, capable of withstanding strong impacts, pressure, friction, etc. It is often made from secondary raw materials (waste paper). Its main disadvantage is a very simple appearance, visually cheapening the product. In addition, this material becomes as cold as a stone in the frost.

Carbon (Carbon fiber) is a fabric made of carbon threads. It is folded into several layers and then impregnated with epoxy resin and dyed. Carbon fiber is a beautiful and lightweight, yet strong material. Carbon is lighter but stronger than steel, it has excellent anti-corrosion characteristics, is chemically neutral and can withstand heavy loads. The main problem of carbon is the high harmfulness of the production of the handles themselves, as the processing of this material affects human respiratory tract. In addition, it fades in the sun and can break under impact loading. Nevertheless, today it is one of the main materials of expensive, premium knives.

Synthetic Rubber

Kraton is a synthetic rubber – a TPE (Thermoplastic Elastomer). Two companies’ elastomers are most commonly used in knife manufacturing. These are Santoprene (Santoprene) material from Advanced Elastomer Systems and Kraton, produced by Shell. Knife handles made of elastomers (Kraton in particular) are produced by high-pressure molding. These materials can be deformed quite easily, and afterwards they take the same volume and shape. A handle made of this material should stick to your hand slightly, which is one of the main signs of a good elastomer.

Elastron (Elastron G) is a polymerized butyl rubber. It is as strong as vulcanized rubber and remains flexible at temperatures from -65° to 150°C. It has good water repellency and resistance to chemical attack. The material withstands high loads and remains warm enough in cold weather. However, when damaged, it quickly deteriorates, falling off in irregular pieces.

Plastic

FRN Thermoplastic (Fiberglass Reinforced Nylon) is a fiberglass reinforced nylon. FRN thermoplastic withstands high temperature loads, has high impact strength, dielectric properties, is well colored, practically does not burn, has low moisture absorption and high chemical resistance, low weight. It is also quite cheap in production. The disadvantages of the material include high fragility in conditions of severe frost. Today it is one of the most common materials in the world’s largest manufacturers.

Today, due to the development of the knife industry and the expansion of the range of knife steels, sharpening knives on diamond stones has become a necessity. This is due to the fact that the vanadium content in modern knife steels often reaches up to 10%, and the tungsten content can exceed 10%. In addition, in modern powder steels the carbon content can approach 2.14%, formally placing such steels in the category of cast iron. Effective sharpening of such steels is possible only on diamond (or elboron) stones. Compared to conventional abrasives, diamond bar provides increased accuracy of tool and parts processing, as well as an increase in tool durability after diamond sharpening in 1.2 – 2.5 times, and most importantly a significant increase in the speed of work.

Diamond powders are the abrasive base of diamond stones. They consist of natural or synthetic diamonds and are divided into two groups: grinding powders and micropowders. Grinding powders are usually used in the manufacture of diamond tools, while micropowders are used for pastes and suspensions. In the Russian diamond industry, for organic bonded stones (intended for sharpening tools), two types of grinding powders are mainly used:

1) AC4. From synthetic diamonds, grains of which are represented by aggregates and aggregates.

2) AC6. Synthetic diamonds, the grains of which are represented by individual crystals with a developed surface, aggregates and intergrowths.

A high quality diamond bar has an inherently higher aggressiveness of cutting precisely because of the grains that protrude excessively above the working surface. In the course of work, these grains either break off or chip out of the bond, and after a short period of initial use, the stone reaches its nominal cut and should last a very long time in this condition.

The organic binder itself consists of phenol formaldehyde resins and various compositions based on them. During hot pressing, the compositions are bakelized into a hard and sufficiently strong substance that holds the cutting grains in the working layer of the tool. At the same time such a bond will be strong enough and ductile enough, but not stiff enough.

The concentration of diamond powder is an important factor in the effectiveness of such a bond. For AC4 and AC6 grinding powders, this concentration leaves 50% or 100%. It is the concentration of diamond in the powder that determines its cutting ability, performance, service life and cost. The choice of concentration depends on the type of tool, the shape and size of the working surface, the grain size of the diamond powder, the wear resistance of the bond, and the machining conditions. To prevent such a bond from being too soft and ineffective on materials with high hardness, additional abrasive grinding powders, such as boron carbide, are added to it.

However, for sharpening the cutting edge of a knife, the bond can be even softer than for a specialized tool without losing effectiveness. For this purpose, the most advanced technology, used, for example, in the production of the Venevsky Diamond Tool Factory, are bars on a new modernized OSB bond. It is based not on grinding powder, but on ACM micro powder made of synthetic diamonds of normal abrasiveness.

What makes OSB bonding different from others is that it does not use boron carbide. In addition, the abrasive layer on it is not sintered, but glued to the body of the metal plate. At the same time the concentration of diamonds in these bars is 100% and already out of the box they are ready to work and do not require leveling on silicon carbide powder. OSB is ideal for hard steels at small angles. You can work on this bond with both soapy water and oil. While the manufacturer himself recommends working with either water or soapy water, working with oil gives an excellent result in terms of cleanliness of the process itself, without leaving such a large amount of water slurry.

Japanese company Naniwa was founded in Osaka in 1941. Its main activity is the production of various sharpening products for cutting tools. Today, Naniwa has an excellent reputation as a manufacturer of high-quality classic water stones for sharpening and is the recognized world leader in the production of magnesia-bonded aluminum oxide abrasives. In addition to premium artificial abrasives, Naniwa also produces a variety of profile accessories such as stone holders and stands, sharpening stones, sharpening stones dressing stones, etc.

Naniwa sharpening stones are synthetic abrasives and are manufactured using the most advanced technology, with a variety of bonding agents. Due to the unique manufacturing technology, these stones are characterized by high performance and due to their structure can be used for any steel with a hardness of up to 68 Rockwell units. Compared to natural sharpening stones, they have a more homogeneous composition and produce much more suspension. The grain is constantly renewed during the sharpening process, resulting in a high performance gain.

Naniwa produces two of today’s most sought-after synthetic water stone series, Naniwa Professional Stones and Naniwa Super Stones, as well as several other specialized series.

Naniwa Professional Stones

The most popular series is the Naniwa Professional Stones or Naniwa Chosera series for the Japanese market. The size of the stone is 210x70x20. This is a series of high quality stones designed for professionals who are professionally engaged in sharpening cutting tools. This series is categorized as professional stones because of its very high productivity. It is this parameter is emphasized by the creators of the Professional Stone series.

The stones are made with a magnesia bond. It is a magnesia cement that hardens in air by mixing caustic magnesite and magnesium chloride solution. Magnesia-bonded abrasive has low mechanical strength and hygroscopicity, so it should be stored in a dry room. Moisture leads to cracking of the bars and their further unsuitability for sharpening work. One of the main features of this bond is its high density with a uniform consistency of finely dispersed abrasive particles. This gives the bars the highest work efficiency among water stones. The most popular stones from this series are:

1. Naniwa Professional Stone #600 series water stone is designed for deburring and rough sharpening.

2. Naniwa Professional Stone #1000 series water stone is for basic sharpening.

3. Naniwa Professional Stone #3000 series water stone is for basic sharpening.

4. Naniwa Professional Stone #5000 series water stone is for pre-finish sharpening.

There are also other stones in the Naniwa Professional series from 400 to 10000. The grit of all these stones is given in the Japanese JIS system.

Naniwa Super Stones

The Naniwa Sharpening Stones or Naniwa Super Stones series for the Japanese market, has the same sharpening bar sizes as the Naniwa Professional Stone series. It is designed for sharpening the widest range of cutting tools, both in terms of purpose and material of manufacture. Compared to the Naniwa Professional Stone Series, this series has a smaller capacity, but the stones are slower to produce. This series is made with an organic bond, with Bakelitized resin as a base. The stones themselves are more durable than Naniwa Professional, but remove metal less productively.

Naniwa also produces other series of stones: Naniwa Specialty Stones are multi-purpose stones for specialized tools. Naniwa (Traditional Stones) – designed to work specifically with Japanese knives and other cutting tools made with traditional technologies such as Shiro Gami (white paper), Ki Gami (yellow paper), Ao Gami (blue paper), etc.; Naniwa Coarse Stone – coarse stones for coarse deburring work, etc.

Naniwa stones, regardless of the series, do not require immersion in water, and a spray gun is required to work with them. These abrasives are sensitive to prolonged exposure to water. They should be dried well and stored in a dry place. If the storage rules are not followed, the stones may crack and lose their abrasive properties. They should not be left wet in the cold, frozen water can destroy the stone. These abrasives may have white salt streaks (efflorescence), which is normal. They should be allowed to air dry when finished. Do not try to speed up the drying process by exposing the bars to heat; they must dry evenly to retain their qualities. Stones that are completely dry can be put away for storage.

Naniwa abrasives need regular dressing to help reduce uneven wear. Stones should be dressed on the thickest possible glass with their own slurry, without silicon carbide powder.

Special stands can be used to make working with these stones more comfortable. They help to prevent the water stone from slipping and lift the stone off the work surface, which is especially useful when sharpening knives.