Types Of Professional Sharpening Systems
Today you can find a number of different professional sharpening systems and devices that are used for sharpening of a wide range of cutting tools.
However, before we start reviewing them, it is worth getting to the bottom of what any professional device actually is.
First of all, the concept of a "professional device" can be compared with the concept of a "high-precision device". A professional sharpening device must have a high level of manufacturing quality and a precise fitting of parts to perform knife sharpening with proper quality.
Only if such qualities are present we can say that this device is intended for professional use or it can be used for running your own sharpening business or for personal purposes.
Among all existing devices there are two main groups, which are capable of sharpening the blades of various cutting tools different in their design principle:
- Based on the operating principle
- Based on the cooling principle
- with cooling
- without cooling
Regardless of the design, all professional sharpening systems and devices are divided into:
- Electric desktop knife sharpeners
- Electric water-cooled knife sharpeners
- Horizontal water-cooled sharpeners
- Horizontal disc sharpeners for sharpening clipper blades and scissors
- Belt-sanding machines, grinders
Electric desktop knife sharpeners
Within this group we can also divide them into separate categories, since some are more versatile and some can only be used for narrowly-specialized knife sharpening. In addition, some devices have some units similar in their application to other devices, however they work in a different way.
There are a very large number of electric desktop knife sharpeners that are similar in operation to the household manual desktop sharpener, sometimes referred to as a pull through knife sharpener. Along with some seemingly advantages, there is one very significant disadvantage. Such manual sharpeners work in such a way that it is necessary to run the knife blade across the vertically placed abrasive elements, which cut grooves on the secondary bevels of the knife and thus destroy the cutting edge and the blade itself, rather than making it sharp. The reason for this is that when the side load is applied, the longitudinal grooves are the point of greatest stress concentration and lead to considerable chipping. With such a sharpener, the knife can become sharp quickly, but it will also blunt very quickly. Such a blade can barely be called sharp and is very difficult to restore without significant changes in blade dimensions and secondary bevels geometry.
The use of an electric drive in these designs has slightly changed the way desktop sharpeners work. Previously stationary abrasive elements are now powered by an electric drive. In some sharpeners, the abrasive elements are mounted in groups and positioned perpendicular to the blade during the sharpening. Other manufacturers have created knife sharpeners with an arrangement of abrasive elements similar to a classic grindstone. The knife sharpening process consists of manually guiding the blade through the abrasive elements. The blade makes contact with the lateral plane of the abrasive wheel and, as a result, you can see a burr on the cutting edge under a microscope. This gives an impression that the knife is sharp, but in fact the biting is due to the burr.
For a better understanding of this type of sharpeners, it is worth listing their main features:
- It is possible to sharpen the knife only at the same angle only for one type and geometry of the blade on each individual sharpener;
- Most sharpeners have only 2-3 sharpening stages;
- Most designs do not allow you to thoroughly clean the sharpener;
- The more expensive ones have removable modules that can be washed;
- If the pulling is uneven, the secondary bevel planes may be changed.
To conclude, we can note that sharpeners of this type are quite often used in home kitchens, while the more expensive and advanced ones are used in restaurant kitchens. Quite often restaurants have one or more sharpeners, which is due to the nature of the work and as a technical solution is quite acceptable in terms of cost.
In the home kitchen, the use of more expensive sharpeners is impractical.
This solution can generally be recommended when using in the kitchen not expensive chef's knives and if there are no special requirements for the condition of the secondary bevels and the cutting edge.
It has been repeatedly verified that the life of even the most advanced sharpeners in regard to the primary biting condition of the edge drops after sharpening 100—200 knives (less advanced sharpeners with aluminum oxide abrasive discs have a much shorter life). In other words, once the abrasive plates enter the working tempo, you will not be able to get the cutting edges of the knives as sharp as before and the maximum service life is about 3000 knives.
Technological evolution has undoubtedly provided a number of design improvements and increased the efficiency of electric desktop sharpeners, but all electric sharpeners of this kind have retained the technical problem of their predecessor in one way or another.
Electric water-cooled knife sharpeners
The main features of this type of sharpening systems are functionality, versatile use and high accuracy, which are ensured by a number of the following properties:
- Variety and versatility
The sharpener with use of different parts can be set up for sharpening a number of different cutting tools and knife blades of different types and sizes. A range of sharpening discs on different bonding agents also makes it possible to work with steels of different hardness. Some manufacturers have separate models designed specifically for sharpening kitchen and chef knives for use in large restaurant and hotel kitchens.
High level of consistency and accuracy of angle adjustment is a feature of quality machines of this kind. The higher quality and more expensive sharpeners have the motor and shaft located under the metal part of the body on which the universal support is mounted. This technical solution provides stable fixation of the universal support with the possibility of adjusting the height above the device. This supporting guide rod is the basis for all types of sharpening work. Knife blades get clamped in suitable fixtures which are guided along the rod. This technique ensures a smooth stroke and a consistent sharpening angle.
Low revolutions of 100 - 200 rpm enable gradual gentle machining during the sharpening process, which gives the precise control over the result of the work. The low speed of the sharpening wheel also minimizes the possibility of overheating the cutting edge and the knife blade as a whole, because the spot of contact with the sharpening wheel is quite large.
Leading manufacturers' sharpeners are equipped with special electronic RPM support to ensure consistent sharpening quality even under high loads. Some sharpeners are equipped with speed adjustment.
The cooling of this type of systems is provided by special grinding wheels designed for sharpening with water mainly for stainless steels. Cooling is also necessary because of the high torque and the mentioned large contact area. Both factors ensure a high efficiency of the sharpener and a high level of knife sharpening quality and thus require water cooling. In addition, the water removes metal and stone particles from the abrasive wheel and prevents it from getting clogged.
All residual abrasive material collects in the water pan and no dust is released into the air. Besides, no sparks are generated, which can be dangerous in certain conditions. Beyond that, the high quality machines are almost silent.
The sharpening machine is quite transportable due to its relatively low weight and can be used outside the workshop. At the same time such a machine and its accessories require a certain workplace, which should be taken into account before purchase.
Learning how to use such a sharpener will certainly take some time, but the investment will definitely pay off if you want to do small projects or small batches. The use of the sharpener in stream production is definitely not recommended, even in spite of the manufacturer's significant warranty period.
The flaws include the fact that the cost of quality sharpeners and their parts is quite high. Some manufacturers, due to the demand, produce their devices at a cheaper price and sometimes with a significant loss in quality and design flaws.
Also, cheaper brands do not offer the full range of possible parts and accessories. It is possible to use parts from other brands, but this is not always advisable. The comparison of using, for example, very expensive car tires on a medium-lower quality vehicle is somewhat relevant here.
In order to properly sharpen a knife with different grit sizes, it is necessary to change the abrasive wheel to a wheel with a smaller grit size, which takes a certain amount of time and readjustment of the machine. The way out can be the purchase of one or more sharpeners or use in conjunction with other units. For example, it can be a quality sharpener with a polishing wheel of different surfaces for deburring and polishing the blade.
Such finishing is often used for commercial application of devices.
To sum up the points above, before selecting and purchasing this kind of sharpener, you should first check:
- material of the body in which the motor shaft and the support rod are fixed
- no possible runout of the shaft, which affects the operation, as it is usually impossible to correct this defect
You can also avoid possible technical defects by purchasing an initially high-quality device with the ability to buy the necessary accessories and supplies.
Horizontal water-cooled sharpener
This group of sharpeners has some similar technical features to the sharpeners described above.
These machines mostly use Japanese water abrasive disc with characteristic properties. The main feature of these machines is that the device operates at low speeds.
One of the disadvantages, in contrast to the vertical arrangement of the abrasive wheels, is that there is no stable support guide and only the side plane of the wheel is used. In this mode, comfortable and relatively accurate sharpening is possible only for knives and cutting tools. Working with small blades remains a very difficult task, because small blades need to be held by hand, which requires certain skills.
Some manufacturers do have various holders, guides, and other accessories for precise work.
If you compare the principle of work with electric desktop sharpeners using the side plane of the sharpening wheel, the difference lies in the diameter and material of the abrasive wheel, which is a noticeable advantage. In addition, sharpening marks will always form on any blade at a certain angle depending on the location to the sharpening wheel. You can achieve a fairly good level of knife sharpening with good and biting sharpness using abrasives available for such machines. Such sharpeners may well occupy their niche for certain purposes, e.g. in carpentries, leatherworking shops or in places where the condition of the secondary bevels and the cutting edge is not of high concern.
It is also worth mentioning that sometimes you can find interesting technical solutions that combine a classic desktop sharpener with the unit, in which the grinding disc is located in a horizontal position with the possibility of water supply. Some have the possibility of adjusting the support not only at a certain angle, but also at a height above the tool.
It is advisable to have a workplace for all such sharpeners, because it is impossible to exclude water splashing and the desktop must be as vibration-resistant as possible in the horizontal plane.
Sharpening machines with horizontal rotary table for sharpening clipper blades and scissors
Sharpening machines with a horizontal rotary table are not commonly used for sharpening regular knives, but in addition to kitchen, hunting and folding knives there are specialized knives, which also have a blade.
Such equipment is designed primarily for sharpening the blades of hair clippers, meat grinders, wire cutters, surgical tools, coffee grinders, etc.
The features of such sharpeners are:
- Knife sharpening is carried out by powder method on an aluminum tapered rotary table with a serrated surface, the other side of the disc is flat
- Some devices allow the installation of diamond discs on the shaft
- It is possible to install a washer with glued sandpaper to perform some honing and sharpening steps for knives
- Most machines are equipped with a frequency converter and have minimal vibration
- Machines are available in various power capacities
- The design includes a speed regulator, some have reverse and soft start
- Most machines are quite compact and can be transported
- The more expensive ones are equipped with additional holders and manipulators
There are some hybrid versions among these types of machines that are more similar to table sharpeners with two vertical discs on a shaft. The technology itself allows the use of a disc, also in a vertical position. These machines are designed to perform a fairly wide range of work, depending on their use with different holders.
Belt-sanding machines, grinders
Belt-sanding machines and grinders among all electrically driven devices stand out for their maximum efficiency. A wide range of different materials for the manufacture of grinding belts, extends the application area, from aggressive metal removal and reprofiling to grinding and polishing.
With this in mind, sharpening on an endless belt can be considered an advanced, modern and efficient machining method. The replication of standard sharpening angles, is achieved through machine attachments and accessories.
The belt sanding machine can be used for sharpening various knives, chisels and other tools, deburring, removal of burr and sanding with the availability of the reversed movement due to the frequency converter.
When sharpening inexpensive kitchen, household and carving knives on a belt sander or grinder, two abrasive belts may be used, followed by a polishing step if a high level of accuracy is not required.
Sharpening more expensive kitchen and cooking, hiking, hunting and fishing knives requires a different approach, so up to 5-6 different belts must be used. Replacing belts and partial readjustments also takes time to complete the process.
However, it is possible to ruin the blade and cutting edge by overheating it if you do not use any cutting fluids and are not experienced in both cases. A better but more expensive choice would be a grinder.
Using a grinder greatly expands the application possibilities compared to a belt sander and is designed for inline production or commercial knife sharpening. In the case of the grinder there are no ready-made solutions and many questions remain open: vibration, belt heating and blade cooling, the question of size and placement of the device, placement of accessories, etc.
Despite the fact that a belt grinding machine can be used to quickly fix geometries and has a certain level of variability, such machines are primarily suitable for roughing, removing chips or at most for budget sharpening. Subsequent processing should be done manually on a more precise machine.
The grinders have two main drawbacks. The first one is that there is no ready-made kit for each individual grinder and you need to customize it for yourself. The second disadvantage is the need for a completely different level of knowledge and skills, high acquisition costs.
Even with sufficient precision of belt sanding machines and grinders, it is still not possible to achieve the results you achieve by hand on Apex-type devices due to the peculiarities of the use of endless belts. Trying to get very thin bevels without cooling or trying to finish the cutting edge on a belt is not a good decision for high-quality steel and expensive knives, as it can simply affect the knife maker's image.
Apex-type mechanical devices
Apex-format mechanical or manual knife sharpening systems can be classified as one of the most technologically advanced groups of knife sharpeners, which got their name from devices developed by a talented engineer a couple of decades ago and have become synonymous with the name of such sharpeners. These manual sharpening systems can basically be divided into three basic sizes:
All sizes of sharpeners have three identical units in their construction:
- guide rod with abrasive holder
- Sharpening angle adjustment unit, where the guide with the abrasive holder is mounted
- Semi-automatic turning mechanism with frame and clamps for fixing the blade
The design of such devices consists of a base, on which the vertical mechanism for adjusting the angle of the abrasive guide with the abrasive holder and the rotary mechanism is mounted.
More than 30 years have passed since this type of sharpeners appeared, and since technical progress never stops, new ideas and developments appear. There are a number of manufacturers on the sharpening system market with devices of various applications.
Some knife sharpeners are equipped with additional units that allow you to make additional adjustments:
- turning mechanism with changing the vertical position in relation to the adjustment unit of the sharpening angle
- Some devices use a special toothed rack or a more complex rack lift to adjust the sharpening angle
- some turning mechanisms have the option of horizontal displacement relative to the base of the sharpening device
- some models have a unit for adjusting the position of the base of the device over the working surface for use with some natural abrasives
- there are devices with a removable frame, which gives additional convenience of visual control of the knife
- some manufacturers have additional parts for sharpening blades with complex geometry
There are systems of sharpeners, which can be upgraded and combined with parts of different models of the same manufacturer and create a sharpener to suit your needs or for sharpening a knife of a certain size or shape.
The obvious advantages of using such systems are:
- high level of consistence of the sharpening angle due to the fixed position of the knife and the angle of the abrasive stone in relation to the blade, resulting in correct shape of secondary bevels and a sharp cutting edge
- guide rod with abrasive holder allows easy work
- The use of special-format bars makes it possible to easily form secondary bevels, to do a precise finishing of them, as well as easy reprofiling in case of damage to the cutting edge
- Stepless adjustment of the sharpening angle and adjustable blade clamping allow you to sharpen blades of different shapes and sizes
Compact systems are perfect for those who need a device of small size and light weight to sharpen small and average knives. The main advantage is the size of the clamps and the clamping frame. Sharpening a knife, especially a small one with a thin blade, will be much easier to carry out with such a device than with others. Such sharpeners will definitely find their place in the household.
Medium-sized sharpening systems, in comparison with full-size sharpeners, are most often distinguished by angle range and by an abrasive holder of a certain standard. Some also have a turning mechanism. Sharpeners can be used in workshops for sharpening small series of various knives with some limitations.
The difference between medium-sized and full-sized sharpeners is somewhat more difficult to distinguish, and pricаe is not the main factor. First you have to decide what your goals are, and then you need to determine your budget.
If you consider the question of the differences of this class of sharpeners as a whole, the large, full-sized devices are obviously the most convenient, because they can cover the widest possible range of knives of different lengths and geometries.
The main points of difference between the sharpeners of all sizes are:
- weight - the bigger the system, the heavier it is, but also more stable
- Range of sharpening angles - the larger the dimensions of the device, the greater the range of sharpening angles
- the difference in the size of the frame and clamps - the possibility to sharpen knives with different widths, thicknesses and lengths of the blade with greater convenience
- compatibility of clamps from different models of the same manufacturer - it is possible to combine and adjust the system to the specific situation
- Different dimensions of the assembled devices affect the choice of workplace and placement of sharpening accessories
Professional sharpening systems of the apex format are complex devices with a number of similarities and differences. The very number of technical parameters and even more so their possible combinations require a certain level of understanding of their purpose.
For those who intend to use such sharpeners, should understand that with experience and the right abrasives, the output quality of such systems is much higher than all others. This also means that a certain quality will always cost a certain amount of time for manual work, so the price of the service for properly sharpened knives will be corresponding.
Choosing a professional device for sharpening knives is a very correct and serious question. It is necessary to understand that using this or that equipment it is possible to achieve similar results of knife sharpness at different speeds. In this case, your personal skill and understanding of sharpening technology will be crucial, because in the end the work is performed by a person, not a device. You just need to understand the essence and principles of knife sharpening, to understand what result you want to achieve at each stage. The truth is that if you do not know how to sharpen knives, then it will be equally difficult to work with any device regardless whether it is cheap or expensive. No machine will give you the skills, otherwise you would not need to learn, so human skill and quality abrasives matter the most, and the equipment itself takes second place.
Besides, it is necessary to understand that any equipment has its own dimensions and requires an appropriate work space. In addition to the device itself, you will need a storage place for accessories and supplies for several reasons: for safety, work hygiene, and personal convenience.
Professional knife sharpening systems and knife sharpeners, combined with high-quality supplies and accessories, will be a powerful tool in capable hands. It can become an interesting hobby, and for someone a business that combines the useful with the pleasant. A properly sharpened knife is the result of labor, knowledge and skill.