How to sharpen a chainsaw chain with a file

Depth gauge adjustment

Many novice users of chainsaws, after sharpening the cutting tooth, forget to adjust the cutting depth limiter, it must be lowered in proportion to the wear of the cutting link. The required amount of sewing can be determined using the template included in the chain sharpening kits.

The depth gauge determines the thickness of the wood to be cut in one pass of the saw chain. If the depth gauge is too low, there will be an additional load on the cutting head due to an excessively deep cut of the tree, strong kickback, chain breakage and increased vibration of the chainsaw are possible.

An oversized depth gauge will not provide the necessary cutting of wood, it moves the cutting tooth away from the tree, which will greatly reduce the efficiency of the chainsaw cutting process.

How to sharpen a chainsaw chain with a file

How to sharpen a chainsaw chain with a file

Sharpening the chain cutting teeth with a file

  • When sharpening the chainsaw, 1/5 of the file should extend beyond the edge of the saw tooth. To maintain the correct angle of sharpening the chain with a file, use the guide clip (sharpening template for the chain file), which is included in the manual chain sharpening kits.
  • When sharpening the chain, observe the sharpening angle indicated on the file holder.
  • When sharpening cutting links, the file must move in one direction. from the inside to the outside of the cutting link.
  • First sharpen the cutting links on one side, then turn the chainsaw around and continue sharpening the cutting teeth on the other side.

Saw chain depth gauge point

If you have no experience with chain sharpening, we recommend that you use the special depth gauge adjustment templates for setting the correct cutting angle that are included with the chain sharpening kits. Depth gauge templates are also called gauges.

The depth of the stop must be checked every third sharpening of the saw chain.

To correctly measure the chain stop, set the gauge so that only one of the chain stops goes into its groove.

If the chain stop extends beyond the template, it must be filed off with a flat file. Be careful not to allow the limiter to be too low relative to the template.

When working with a flat file, do not grind other chain elements, work only with a template.

The depth stops of the saw chain cannot wear out during the operation of the chainsaw, if you notice wear, replace the chain.

Chain sharpening errors

When manually sharpening the saw chain without a template, the sharpening angle may be violated.

HOW TO SHARPEN A CHAINSAW WITH AND WITHOUT A FILE GUIDE, ADJUST DEPTH ADJUSTERS

It is necessary to regrind the cutting tooth, to correct the angle, use a guide holder (sharpening template), on which the sharpening angle will be indicated. Depending on the type of chainsaw, the sharpening angle can be from 25 ° to 35 ° (for cross cut), the required sharpening angle is indicated on the chain packaging.

Sharpening the saw chain with an oversized file.

If you use a file of an unsuitable size or if the cutting link is sharpened too much, the formation of a small angle of the cutting tooth or the collapse of the side edge may occur.

In this case, it is necessary to re-sharpen the cutting links with a file of the required size, the required file size (from 4 mm to 6.4 mm) is indicated on the chain packaging.

File

For sharpening and straightening saw chains, two types of files are used. The first is a round file with a diameter corresponding to the diameter of the rounding of the working edge of the saw tooth.

For sharpening saw chains of household tools, round files with a diameter of 4, 4.8 mm are used, due to the fact that they have a small tooth. For professional models, more powerful chains with a larger tooth are used, and accordingly files with a diameter of 5.2, 5.5 mm are needed.

In order to sharpen correctly, it is not enough to sharpen only the cutting edges of the tooth, you also need to adjust the cutting depth limiter. If this is not done, the chain will not cut into the material being cut to the required depth, which will noticeably reduce the speed of work and, just like in a situation with a blunt chain, can lead to overheating of the saw motor due to insufficient load on the motor. This work is done with a flat file.

It is worth remembering that the use of a blunt chain can lead to overheating of the engine and the formation of scoring on the cylinder.

When to sharpen

There are a number of factors that will tell you when it’s time to sharpen your chainsaw chain:

  • Decreased productivity. Increased cutting time.
  • Feels overload on the saw.
  • Increased vibrations.
  • Small shavings.

For beginners, it is difficult to notice the first 3 points, so it is recommended to keep track of which chips are flying out of the cut.

Small chips from the sawing process, especially brown in color, are a guaranteed sign of dullness.

Electric machines

For straightening a large number of chains, as a rule, in service centers or in manufacturing plants, electric sharpening machines are used. Depending on the manufacturer, the design of the machines may differ, but they have the same principle of operation.

The saw chain is installed in a special guide, which is mounted on the basis of the turntable and has a special retainer to hold the sharpened tooth.

The latch is able to move horizontally. An electric emery is installed at an adjustable angle to the sharpened tooth, which is turned on by the operator by pressing the start button.

sharpen, chainsaw, chain, file

The immersion depth of the emery, as well as the angle at which the sharpening is performed, can be adjusted. The dive itself is performed by the operator. The chain is straightened with a special grinding wheel, which can be changed if necessary.

In this video, you can familiarize yourself with the sharpening process, the most popular methods and tools used for this.

Sharpening with a file

The first thing you need to sharpen the chain, or tweak it a little, are special files.

How the Pro’s sharpen a chainsaw

How to sharpen a chain on a chainsaw with your own hands

A person who has a chainsaw in his household should know how to sharpen a chainsaw chain with his own hands. There are several ways:

  • Sharpening with a file (the most common method of sharpening, because it allows you to sharpen the tool directly at the cutting site.)
  • Sharpen using a special machine (this method is used in service centers, but can also be used on a personal farm)
  • Sharpen with an angle grinder. For sharpening in this way, certain skills are required. Uncommon method, because it is quite difficult to sharpen with an angle grinder correctly.

Description of the sharpening process with files

The first thing to start with straightening the saw chain on the saw is placing the tool on a flat surface or table. In forest conditions, a large diameter chock is well suited for this. Next, you need to inspect the saw chain for any defects, it can be cracks, completely broken off teeth. After inspection, you need to set the brake in working condition, thereby blocking its movement on the tire.

The chain must be taut when sharpening with a file.

It is advisable to put a stand under the tire, as it you can use a log, a piece of a branch of a suitable diameter, or the manufacturers of sharpening tools have special clamps to hold the bar in the process of sharpening the chain.

The chain is sharpened by moving the file from the inside of the tooth to the outside. In this case, the file should be located parallel to the special mark on the chain. This mark is applied by the chain manufacturer to indicate the standard sharpening angle.

The sharpened tooth should be located approximately in the middle of the tire, this is necessary for the convenience of work, during the sharpening process, you need to move the chain along the tire, not forgetting to set the brake to the working position each time.

Work on sharpening the chain on a chainsaw must be carried out using gloves made of coarse material, otherwise it is quite easy to injure yourself, because the working surface of the teeth is very sharp.

Ideally, manufacturers advise to make the same number of file movements for each tooth, but in practice this is not always possible. teeth have different degrees of damage to the working edge.

To facilitate sharpening the saw chain with a file, special holders can be used, with corner markings applied to them. The markings are made not only for the standard cross-cut, but also for the longitudinal.

Tool holders are also handy if you don’t have sufficient sharpening experience. Experienced sharpeners do not use holders for sharpening, but can only use special devices that support the file.

Another device designed for sharpening is a manual saw chain straightener. It uses a regular file as a sharpening tool, which can be replaced independently. The machine is mounted directly on the tire, it also has the ability to adjust the angle of sharpening of the tooth and a special stop that holds the sharpened tooth.

Manual sharpening machine, perfect for beginners. Along with electric models of sharpening machines, manual has its undeniable plus in the form of a low price. Depending on the manufacturer of the hand-held machine, their appearance may differ, but the principle of operation is the same for all.

The depth of cut is adjusted with a flat file, so that there is a difference between the upper cutting edge of the tooth and the height stop.

As you can see from the figure, the depth gauge is grinded in such a way as to bring the gap indicator to the factory value. Below is a table showing the main values ​​of the angles, as well as clearances for the most common types of chains.

As a rule, the size of the gap is adjusted using a special die. It is installed on the chain during sharpening, after which the depth gauge is grinded.

For more information on how to sharpen a chainsaw chain with a file, read here.

How to sharpen a chainsaw chain with your own hands

The chainsaw, although it is intended for cutting wood, but in the process of work, the chain still becomes blunt and requires sharpening. As part of the article, we will tell you how to determine when to sharpen and how to do it yourself, as well as analyze all possible methods (from a file to an angle grinder) and which ones are better to use.

Application of a roller fixture

The sharpening device, with which you can quickly and efficiently correct the teeth, consists of a small guide template, on which two rollers are installed.

By installing the device on the tire, you can sharpen the teeth of the chainsaw, even without experience in such operations.

Round file

Round ones vary in diameter. The main diameters are:

  • 4.0 mm
  • 4.8 mm
  • 5.2 mm
  • 5.5 mm

Depending on the size of the tooth, it is necessary to choose the optimal diameter. To facilitate the process, special file holders or support rollers with a designation of the angle of sharpening of the tooth can be used.

Filing gauges

These devices are used to control the angle of sharpening of the teeth, as well as the distance to the depth gauge in conjunction with a flat file.

Files and fixtures

The main one with which the working saw tooth is sharpened is round. Flat is used to adjust the height of the tooth. cutting depth limiter.

Sharpener

Manufacturers of equipment for chainsaws make special guiding machines for installing a file and sharpening in them. The machines are mounted on the chainsaw bar and are adjustable in height and angle to the chain. The use of such equipment is relevant for those who are just trying to learn how to sharpen a STIHL chainsaw chain with their own hands.

Clamp

This device allows you to hold the bar of the chainsaw while sharpening. For its correct use, the process must take place directly at the cutting site. The clamp is hammered into a tree or board, then the tire is clamped into it and securely fixed against displacement. The device can be used for all types of tires, regardless of size.

In some cases, for example, in garage conditions, instead of a clamp, you can use a conventional vise, the tire is clamped in them so that the jaws of the vise do not interfere with the free movement of the chain. Further, sharpening is performed according to the usual scenario.

Description of the sharpening process

Let’s take a closer look at how to sharpen a chainsaw chain. The first thing to do is to prepare a place for installing the clamp, or if the process takes place without it, then it is convenient to use a regular log as a stop for fixing the tire in the horizontal plane. The chainsaw is installed on a flat surface, the log is placed under the tire, the brake is activated.

To avoid injury when sharpening your chainsaw, be sure to apply the chain brake.

How to sharpen a chainsaw

The next stage is direct sharpening of the tooth. To do this, a round file is made movements from the inner side of the tooth to the outer.

It is very important at this point to maintain the correct sharpening angle. The standard angle is thirty degrees from the file perpendicular to the plane of the tire. How to position correctly shown in the photo below.

In the process of sharpening a chainsaw for a non-standard cut, for example, longitudinal. The sharpened angle is changed to a less acute one. As a rule, it is no more than 10 °. It is in such cases that a holder, hand-held machines or filing gauges are used to control the sharpening angle.

Some manufacturers of chains for chainsaws, to facilitate sharpening, as well as to indicate the maximum possible sharpening, a special mark is made on the upper surface of the tooth.

By keeping the file parallel to the mark, you can be sure that the correct angle is being observed.

The number of working movements with a file should be the same for each tooth. This will allow all teeth to be ground evenly.

In the process of straightening the chain, it is customary to sharpen the teeth first on one side, and then on the other, this is convenient since there is no need to constantly change its position in relation to the chainsaw.

After the working teeth have been sharpened, it is necessary to adjust the height of the limiting tooth with a flat file. For this, the filing gauge is placed on the chain in such a way that the limiting tooth coincides with its slot, after which the protruding part is grinded with a file. This procedure is performed on all restraining teeth.

Flat file

Flat should have a width of no more than 1 cm.It is convenient to sharpen the stop tooth with the help of a special bar (filing gauge), which is installed on the chain and shows to what maximum depth the tooth must be sharpened in order to achieve optimal performance of the chainsaw.

How to sharpen with an angle grinder (angle grinder)

The method of sharpening the saw chain using an angle grinder, the least common due to its insecurity. In order to straighten the teeth of the chain using an angle grinder as a sharpening tool, you must install it in a vice and clamp it securely. Then the tool is switched on and the sharpened edge of the tooth is placed on the rotating surface of the disc. A tooth sharpened in this way can differ significantly from that sharpened with a file, because in the process of dressing using an angle grinder, it is rather difficult to control the sharpening angle.

A big disadvantage can be considered the possibility of a notch with an angle grinder disk of the eyelet for attaching the connecting link of the chain, which in the future will lead to a rupture during work. If, in the process of carrying out work using a chainsaw, the need arose for sharpening, it is better to use a special tool than to come up with various tricks that can result not only in financial losses, but cause serious injuries during their implementation.

Sharpening the chain is not as difficult as it seems at first glance. Any person, after studying the process of straightening chains, is able to sharpen the cutting set of his tool on his own. Even if the first time it turns out to be done not quite qualitatively, you should not despair, because with every next try, the result will be better and better.

The use of chainsaws allows you to change the size and shape of wood and other materials. The cutting element of the chainsaw is the chain, which moves at high speed during operation. There are blades on the chain, the geometry of which ensures fast cutting. Over time, the chain becomes dull and the teeth need to be sharpened. Sharpening the chain is a procedure that you can perform yourself, since it is no more difficult than sharpening another cutting tool. The only conditions for sharpening can be called the use of a special design. This is due to the fact that the created tooth has an unusual geometry: it consists of two cutting edges, the angle is created using the lateral and upper planes. The particular difficulty of sharpening is that the upper surface has an angle relative to the mowing line of the chain movement, which must be maintained with great accuracy.

How to sharpen a chain on a chainsaw with your own hands

Determining when a tool needs maintenance is simple. It becomes clear in the process of work on the following grounds:

  • the shavings become small;
  • significant effort is required;
  • the saw jams;
  • strong vibration is felt;
  • cutting time increases.

By looking closely at the chain, you can visually make sure that the edges do not have the necessary sharpness. Having found that the time has come to sharpen them, this procedure cannot be postponed. First, the job becomes unsafe for the performer. Secondly, there is an unwanted load on the power unit. And thirdly, a lot of time is lost, some of which is better spent on sharpening.

The sharpening principle is based on the design features of the link. It consists of a body on which the L-shaped cutting edge is located. The vertical edge is straight and the horizontal edge is angled. A cutting depth gauge is located in front of the tooth. All these elements need to be processed.

The seaming cutter reduces the chain profile height. If the height of the limiter is not removed in parallel, then it will not allow the tooth to sink into the wood to the desired depth, so it is also grinded. Stop dressing is done in significantly smaller volumes.

The cutting edge is reduced when sharpening in height by a fraction of a millimeter. It is this value that you need to focus on when processing the limit stop. For work, you can use a file, an angle grinder (angle grinder), special mechanical devices and electrical tools.

Electric grinding machines

For straightening a large number of chains, as a rule, in service centers or in manufacturing plants, electric sharpening machines are used. Depending on the manufacturer, the design of the machines may differ, but they have the same principle of operation.

The saw chain is installed in a special guide, which is mounted on the basis of the turntable and has a special retainer to hold the sharpened tooth. The latch is able to move horizontally. An electric emery is installed at an adjustable angle to the sharpened tooth, which is turned on by the operator by pressing the start button. The immersion depth of the emery, as well as the angle at which the sharpening is performed, can be adjusted. The dive itself is performed by the operator. The chain is straightened with a special grinding wheel, which can be changed if necessary.

How to sharpen a chain on a chainsaw with your own hands

A person who has a chainsaw in his household should know how to sharpen a chainsaw chain with his own hands. There are several ways:

  • Sharpening with a file (the most common method of sharpening, because it allows you to sharpen the tool directly at the cutting site.)
  • Sharpen using a special machine (this method is used in service centers, but can also be used on a personal farm)
  • Sharpen with an angle grinder. For sharpening in this way, certain skills are required. Uncommon method, because it is quite difficult to sharpen with an angle grinder correctly.

In this video, you can familiarize yourself with the sharpening process, the most popular methods and tools used for this.

Tooth parameters

Two cutting edges are formed on the blade, one is located on a horizontal plane, the other at an angle. To obtain the required parameters, the blades are sharpened at the angle specified in the technical specifications. Rake angle is sharpened from 60 to 85 °.

The back angle indicates the backward tilt of the upper blade. It lies in the range from 50 to 60 °. The blade located on top is considered the main one, the clearance angle in this design is very important. It is difficult to measure it, when following the rules of sharpening and observing the geometric parameters, it is formed in the specified range.

The corners are sharpened depending on the use of the tool. The main rule is that the larger the angle, the more efficient when processing soft wood, the smaller the angle, the easier it is to operate the saw with hard wood. That is, the smoothness of the stroke is improved and the vibration of the tool is reduced.

Meanwhile, the situation of sharpening the angle greater than 35 ° and less than 25 ° should be avoided. This rule does not apply to rip chains.

The corners are changed when editing the tool. They have an important effect on the cutting parameters, therefore all technical requirements must be met carefully.

How to sharpen a chainsaw chain with your own hands. Step-by-step instruction

Bringing the chain into working condition has its own characteristics. They are determined by the configuration of the tooth. It includes two edges, one at the top and the other at the bottom. over, the edge located towards the top has a slope at a given angle. In fact, the tooth, both in geometry and in the principle of operation, is similar to a blade from a carpentry plane.

For competent sharpening, the master must understand the structure of the tooth.

Application of special machines

It is not always possible to use a hand tool with a template. For example, if the cutting edge touches the ground during operation, there is a possibility of its deformation. In this situation, a special machine is used. There are two types of machine:

The machine tool has a design that looks like a bow saw, but with a round file. The machine can be used to align the length indicator of all edges, to restore the correct geometry. The considered machine has a complex system for setting processing parameters. Sharpening is carried out in about 2-3 movements, after which the machine is installed in a new place.

The electric machine is easy to use. A special system of settings allows you to correctly position the workpiece surface, as well as bring the disc with high accuracy. Some models have an automatic vise clamping system when the disc is lowered. The cost of the electrical version is slightly higher, but this significantly increases productivity, you can achieve the most accurate result.

STIHL saw chain sharpening guide in PDF format

Hand-operated machines

The design of such a machine is similar to a bow saw. Only where the saw blade is located is the round file. With such a machine, you can sharpen and straighten the teeth, adjusting the proportionality of the upper edges to the smallest (control) size. The mechanism allows you to accurately set the parameters. After adjusting to the “control” tooth, sharpening is carried out in two or three movements. And then the transition. to the next tooth.

When it is necessary to grind off the stopper, we change the round file to a flat file.

Advantages of the method: Allows you to sharpen teeth, including those that have lost their original shape, in a high-quality, convenient and without large physical costs.

Disadvantages: The price of the tool and the distance from the possible site of the saw operation.

“After finishing the“ sharpening procedures ”, blow out the chain with compressed air (from a compressor or pump) and put it briefly in clean engine oil. Of course, almost no one does such events, but for the chain, they will only benefit. “

What to choose for sharpening is up to you. This is due to how often you use your chainsaw. From the accuracy of handling it. From the quality of the purchased chain. And, of course, from the opportunity to spend a certain amount. It is impossible to compare the methods, because as the German proverb says. “apples should be compared with apples”.

We work with a file

The best solution is simple gadgets for sharpening work. This set includes a round and flat file, special holders, a gauge template, a hook for removing chips, etc. Structurally, “adaptations” may differ, but the functionality has a common logic.

The diameter of a round file is directly related to the size of the chain:

  • – Chains with ø 1.3. require a file of ø 4 mm (used much more often);
  • – Chains with ø 1.6. require a file ø 5.2 mm;
  • – To sharpen the depth gauge, use a flat file.

Sharpening process

  • Having previously “turned on” the chain brake, firmly grip the tire of the chainsaw in a vice (a firmly clamped saw is the key to successful sharpening)
  • Set the template so that the arrow points towards the nose of the tire. Be sure to mark (with chalk) the tooth from which you started sharpening, otherwise you can go along the second circle;
  • Sharpen in the direction of the arrows. Remember, there is a special factory cut on each tooth in the chain. It indicates the maximum sharpening angle.
  • In addition to the cutting tooth, there are stops on each link. They are sharpened as needed. This is necessary when, as a result of sharpening, the height of the tooth decreases, and problems arise in the operation of the chainsaw. As a rule, the limiter is sharpened after 2-3 sharpening of the teeth;

“If you don’t have the skills to sharpen, it’s better to start with inexpensive chains.”.

Recommendations:

  • The file should not go beyond the upper part of the cutting edge by more than 1/5 of the working part of the file. The pressure is carried out with the same effort;
  • The movement of the grinding tool is performed in one direction “away from you”, and the number of movements for each tooth must be equal;
  • To sharpen a vertical plane, the position of the file must be at right angles;
  • For sharpening the horizontal plane, file position, at an angle of 20-30 °
  • If there are teeth of different heights, the reference is the smallest.

Advantages: Ability to “charge the saw” in the field. At the same time it’s cheap.

File

For sharpening and straightening saw chains, two types of files are used. The first is a round file with a diameter corresponding to the diameter of the rounding of the working edge of the saw tooth.

For sharpening saw chains of household tools, round files with a diameter of 4, 4.8 mm are used, due to the fact that they have a small tooth. For professional models, more powerful chains with a larger tooth are used, and accordingly files with a diameter of 5.2, 5.5 mm are needed.

In order to sharpen correctly, it is not enough to sharpen only the cutting edges of the tooth, you also need to adjust the cutting depth limiter. If this is not done, the chain will not cut into the material being cut to the required depth, which will noticeably reduce the speed of work and, just like in a situation with a blunt chain, can lead to overheating of the saw motor due to insufficient load on the motor. This work is done with a flat file.

Electric grinding machines

For straightening a large number of chains, as a rule, in service centers or in manufacturing plants, electric sharpening machines are used. Depending on the manufacturer, the design of the machines may differ, but they have the same principle of operation.

The saw chain is installed in a special guide, which is mounted on the basis of the turntable and has a special retainer to hold the sharpened tooth. The latch is able to move horizontally. An electric emery is installed at an adjustable angle to the sharpened tooth, which is turned on by the operator by pressing the start button. The immersion depth of the emery, as well as the angle at which the sharpening is performed, can be adjusted. The dive itself is performed by the operator. The chain is straightened with a special grinding wheel, which can be changed if necessary.

How to properly sharpen a chainsaw chain with a file by hand

Everyone knows that the saw chain, which is used in chainsaws, needs to be sharpened periodically, but not everyone knows how to do it correctly. Determining that the saw requires sharpening the chain is very simple, for this you need to inspect the sawdust, and if they consist of fine dust, then the tool needs to be sharpened. If it is impossible to sharpen, it is worth replacing it with a new one.

The use of a chain that is not sharpened can lead to overheating of the engine and the formation of scoring on the cylinder.

We will analyze the main ways with which you can, without problems, sharpen the chain on a chainsaw.

Chainsaw teeth

Chainsaw teeth have a specific geometry. You need to understand and know what part of them should be sharpened. In general, the “logic” of cutting wood resembles a plane.

The cutting surface has two edges. One is lateral, the other is slightly beveled. The cutting depth limiter adjusts the thickness of the chips. Let’s take a closer look. The elements of the cutting-working link are arranged as follows:

  • Base with axle holes;
  • Tooth scapula;
  • Cutting depth limiter;
  • End face of the blade (placement. vertical);
  • Top edge of the blade (placement. horizontal);

Sharpened edge Dull After touching the ground

After sharpening, the height of the stop and the angle of the sharpened working edges should not differ greatly from the parameters specified by the manufacturer. This is an important condition and it needs an “eye and eye” behind it. Otherwise, the saw will not work as expected.

Do not over-grind or change the location of the links. The normal operation of the instrument depends on the identity of their location. Otherwise, increased stress on the chassis, tire and engine is likely. The cut can be crooked. There is also a small chance of breaking the circuit.

File sharpening

For work, you need two files: round and straight. The first one is chosen along the oval in the link body. There are no diameters larger than 6 mm on household chainsaw chains. Usually this size does not exceed 5.5 mm. A larger file cannot be used. It will change the geometry of the cutter.

There are two main hand sharpening technologies. The simplest method is when the file is visually controlled. The craftsman observes the angles of the factory processing as much as possible and carefully, under full visual control, processes the vertical edge.

The tool partially touches the horizontal edge. Then, with a flat file, it is brought to the desired state and slightly pass along the limiter.

The second method is more accurate and productive, sharpening chains for chainsaws with your own hands with a file is done using a special holder for a round product. With such a device, sharpening a chain for a chainsaw with your own hands is easier.

It is configured so that both faces can be machined in one pass. The file moves vertically and horizontally along the cutting edge. The device significantly reduces the sharpening time, makes it better. The depth gauge can be removed with a straight file. Despite the technological difference for both methods, the general rules are:

  • the chain must be fixed in a vice;
  • the angle of the file relative to the tire is observed (about 30 °)
  • done 2-3 movements from oneself with the same effort.

You can make a device for sharpening chainsaw chains with your own hands for a maximum of an hour. The photo shows an image of the factory device. Making the same at home is not difficult for an ordinary home craftsman.

Sharpening with a round file