Sharpening of a knife of the MTD lawn mower with your own hands. Remove the knife

How to sharpen a lawn mowing knife.

Reducing the quality of the haircut of grass when working with a lawn mower is, in most cases, a sign that the knife of the tool has become dull and the sharpening or replacement of this part is required. At first glance, it may seem that it is easier to replace a dull tool. buy a knife for a lawn mower. But this is due to costs, and finding a knife of the desired configuration may be quite difficult. This option is justified only with significant damage to the cutting edges or damage to the knife in a collision with a solid obstacle, for example, about a stone.

Most often, restoring the knife performance is quite simple. to sharpen a lawn mowing knife with your own hands.Sharpening of a lane of a lawn mower or its replacement can everyone on their own, for this there is enough initial skills in working with a manual tool.Please note that the sharpening technology depends on the type of knives installed on the lawn mower. For work on the lawn, two types of equipment are used. lawn mowers with a rotary knife and a drumsy lawn mower. We describe the process of sharpening a knife for each type of knives separately.

Sharpening of a knife lawn mowing knife.

Gasoline lawn mowers; Electric lawners. wired and accumulative.

In their equipment, mainly double.packed knives are used, less often a knife with four blades. The sharpening technique for all types is one, and has no differences.

Working gloves; The key to the uniform, or end of the corresponding size; A set of files, an abrasive bar, or an electric sharpener.

Before proceeding with the sharpening of the mowing knife, it is necessary to perform several preliminary operations:

Prepare the lawn mower for the removal of a knife. Particularly attentive to this stage must be treated by owners of gasoline models of lawn mowers. It may be required to drain fuel, oil; Turn the lawn mower to access the cutting tool; Fix the knife with a wooden bar; Using the necessary tool, usually a end or a united key, to turn out the knife mounting elements; Remove the knife itself.

After cleaning the knife from adhering grass, dirt can be proceeded directly to sharpening.

To sharpen a lanel from the lawn mower, you will need a stable base. a table or a workbench, on the surface of which you can conveniently place and fix a knife for final sharpening. The best option is if you have the opportunity to fix the knife in a vice.

When performing the work, keep in mind that the working part of the knife is tempered, you should try to ensure that the effect on the blade is minimal and maintain the angle of sharpening of the lane of the lawn mower.

If the working parts of the knife are not damaged. burrs, zazubin, then you can limit yourself to the editing of the blade. Why can you use an abrasive bar or a file with a diamond spray. It is not necessary to remove a large amount of metal, and you can do with a “thin” tool.

If the knife blades have damage, before sharpening it is necessary to remove them with a rough file, on an emery circle or using an electric tool with an abrasive nozzle.

If you do work with a file or abrasive bar, then sharpening is made from the center of the knife to the edge. The movement of the tool is “from yourself”. After performing the work, it is necessary to check whether the balancing of the lawn mowed knife has changed.

The sharpened knife can be installed on the lawn mower and proceed to cutting the lawn.

How to properly sharpen a lawn mowing knife

So that the lawn pleases you with a pleasant color and is healthy and well.groomed, it is necessary to periodically sharpen the knife. How often you need to sharpen a knife, it is very difficult to say for sure, the time between sharpening for all lawns, knives and lawn mowers are different. It is enough to pose a question differently: “How often you need to sharpen a kitchen knife?”, There is only one answer:” At once it seems to you that he was dull “. As well as for knives of lawn mowers.

How can a lawn mowing knife sharpen:

Some craftsmen sharpen the knives with a corner grinding machine (corner grinding), but we strongly do not recommend this for security purposes.

To sharpen the knife, you must first remove it. The knife is removed quite easily. To do this, it is necessary to put the lawn mower to the deck of the deck, tilting back to the handles, having previously loosened the fasteners of the handle bolts.

Please note that the gasoline lawn mower cannot be tilted to the right side, towards the carburetor, since the oil from the crankcase will fall into the carburetor and cause inconsistent consequences, such as pollution of the fuel system, sticking the needle of the carburetor and it may even require repair of the lawn mower in the service center. We also do not recommend tilting the mower to the left side, towards the muffler, since when the shaft is scrollful, there is the possibility of oil from the crankcase into the muffler, which can also have not very pleasant consequences, such as intense white smoke from the muffler.

So, we unscrew the knife counterclockwise, in 99% of the lawn mower, the knife is unscrewed precisely counterclockwise. Be careful and attentive, many lawn mowers are equipped with frictional devices, do not lose the washers and sleeve of the knife drive system. Try to remember the procedure for installing all elements.

Next, it is necessary to clean the knife from adhering grass and earth. Since excess grass we will interfere with us with further balancing.

We fix the knife for the convenience of sharpening, when using a file, or a donkey.

You need to sharpen the knife in the direction of the past sharpening, at an angle of 30 degrees from the horizontal line. All knives for lawn mowers are sharpened from above, a flat platform remains below. Do not sharpen a knife on both sides, as we usually sharpen everyday knives, or hide from below, as this can worsen the quality of the cut and collection of grass.

The sharpening length must be done 11-13 cm, for ordinary knives and 15-20 cm for mulch knives. You do not need to sharpen anymore, since this length is a working one, closer to the middle of the knife, the cut of the grass is not made, this is due to the frequency of rotation of the knife.

If you drag the knife this is not the first time remember that the maximum depth, at which all the dynamic properties of the knife are preserved, is 10 mm. Do not sharpen a knife if the depth exceeds 1 centimeter if you value the beauty and health of your lawn.

After you sharpened the knife, you need to remove the excess metal on its reverse side. Easy enough movement, without effort, to spend on it a file, or a donkey.

Next, you need to balancing the knife in order to avoid unnecessary, unnecessary, vibration of the lawn mower. In order to produce proper balancing, you must have a special balancer for a lanage of the lawn mower, but if you do not have it in the arsenal, you can use a regular screwdriver, or an iron rod. We insert the screwdriver into the central hole of the knife, in the center, and if one of the wings tends down, then remove the excess metal from the other side. We achieve the balance so that no knife wing will outweigh.

Everything, the knife is ready for operation. Next, install it back, do not forget to install all the fasteners in place. If you have a dynamometric key, then tighten the knife bolt with a force of 51-68 N.m., or 5.2-6.97 kilogram-scales. If there is no special key, then on the Internet you can easily find an article on how the data is translated into a simpler designation: hand. Bezmen. Meter pipes.

We wish you a pleasant mowing and a beautiful, healthy lawn.

And if you need to sharpen a knife by professionals, or the prevention of a lawn mower, you can contact our service center, you can familiarize yourself with the services and in the section of our site: Repair of lawn moutines.

Removing knives from a lawn mower

Good sharpening quality can be obtained when using an emery machine with a device for processing at a certain angle.

The knives on many models are attached to a bolt located in the center with an additional puck or a special bracket. The bolt must be unscrewed with an open key or head by 19. If the twisting is difficult or not enough effort, you need to knock on the bolt with a hammer. Blows should be slightly, with a high frequency.

You can spend several series of strokes. If after this it is not possible to unscrew the bolt, the connection must be watered with brake liquid or pepsi-collars. Leave in this state for several hours. Many experts confirm the ability of Pepsi Cola to facilitate the promotion of threaded products.

Use various levers and amplifiers extremely carefully so as not to tear the bolt head or break the mechanism for fixing the shaft.

If it is impossible to remove knives, you should contact specialists or to the service workshop yourself. With minor damage to knives and free access, you can try to sharpen them without removing the tool.

Methods of sharpening knives

After removing the knife, you need to correctly evaluate its condition. Knives of many models undergo special heat treatment to increase hardness. Typically, such data are indicated in the manufacturer’s instructions. In the presence of dents and bends of the knife, you can leve it with a hammer on a flat hard surface. The best option would be the use of blacksmithing. In the absence, you can use the railway rail, a piece of flat sheet metal with a thickness of more than 16 mm or a segment of the metal rolling of sufficient strength. The product cracking during leveling, further processing is not subject to. Knives can be sharpened in the following ways:

Sharpowing operation is more convenient to perform with a fixed tool, moving the knife in a circle.

After aligning the knife and removing dents on the edge, you can start sharpening. Depending on the existing tool of the work can be performed in various ways. For most options, it is advisable to have a locksmith vice that can reliably fix the part in the right position. Small damage can be removed when processing with a file or coarse.grained stone for sharpening. The final refinement of the knife must be performed with fine-grained stone or sandpaper 0th or 1st number. Manual sharpening requires certain physical efforts and time spent. You can speed up the process in the presence of electrodele with an appropriate nozzle. A sandpaper with a shaft must be fixed in a drill cartridge, connect the drill. Fix the knife in any available way. Run the drill, start sharpening the edges. The force should be small, moving the circle on the surface smooth. Do not overheat the edge of the knives. When working, the knife periodically needs to be moistened. The option will be more convenient on the contrary: if possible, fix the drill, move the knife on the stone.

How to sharpen a lawn mower to sharpen yourself ⁠ ⁠

The blades of the knives of various lawn mowers are almost always made of high.quality steel, however, despite this, they are still periodically necessary to tighten them. And most importantly. to do it so as not to worsen the quality of the metal. However, no special tools and skills are required for this, and any summer resident will easily be able to cope with such a task!

Why do you need to hide the knives of the lawn mowers?

Of course, cutting off excess juicy green grass from your favorite lawn is quite real and a knife with blunt edges. But the grass, as a result of such manipulations, will begin to be relaxed (this stratification will go mainly in the longitudinal direction), gradually turning into an inaccurate fringe. And after a few days, it will even dry and can even get sick for several weeks. That is why the cuts should always be neat and even-in this case, they are delayed in only a few hours and allow you to maintain a spectacular juicy green lawn. And in order for them to be such, it is necessary to periodically drag the knives of the used lawn mowers used!

Before proceeding to such an important event, it is important to try to secure yourself and the garden gadget to the maximum. This is especially true for gasoline lawn mowers (models with electric drive are easily neutralized by elementary disconnection from the network): first it is necessary to free the spark plug from the cap, and then you need to completely exclude the probability of fuel leakage. This can be done in two ways. both by draining the tank, and by laying under the lid of rubber hermetic membranes and overlapping the fuel crane. If there are no other instructions in the instructions, then the lawn mower is turned exclusively towards the handle. And before you do this, the hose intended for exhaust gases should be suppressed. this will help to avoid oil leakage.

Knives in various models of lawn mowers can have the most diverse configuration, but the thread on the bolts is always unscrewed the same way. counterclockwise. And to prevent the possible rotation of the shaft, you can place a bar firmly stolen in the ground under the knife. And, of course, in order not to confuse anything, setting the knife back, it is important to try to remember or even draw the position of the blades.

The removed knife must be cleaned from hardened herbal juices, as well as from the mud that has sticks on it. The easiest way to do this is using metal stains. Then the surface of the knife is examined for the presence of any curvature or tubercles. If there are such, they are straightened with a regular hammer with slightly rounded edges of the box. As a rule, the knife begins to rule from the edges of the curved area, gradually moving to its center. It also does not hurt to check and often extending from the blows casting blades, because if they bend at unequal angles, this will inevitably entail a deterioration in the air flow, as a result of which the cut grass will simply not properly mulch.

The next step is to remove the descent. First, get rid of excellent chips, taking the edge of the blade at the same angle along the entire length of the cutting part. And the descent at the required angle will help a small file or an electric sharpener equipped with a carburond stone. At the same time, it is important to try to remove metal from the knife as uniformly as possible. But the corner grinder for these purposes is strictly not recommended, since it can significantly worsen the quality of the pulled blade.

For sharpening the blade, a flat sandpaper is usually used, the granularity of which is in the range from 400 to 600 grit. Before proceeding to the grinding of the blade, it is recommended to soak the bar for ten to fifteen minutes in soapy water. Periodically during the sharpening process, this manipulation must be repeated. And the knife should be hidden by pulling the bar in the direction from the center of the sharpened area to its edge. At the same time, it is desirable that the stone be in the same position. this will contribute to maintaining a constant angle. And, of course, the same amount of metal should ideally grind from the knife blades!

The sharpened blades must also be “corrected”. To do this, you need a small piece of moisture.resistant sandpaper, the grain of which has a range from 600 to 800 grit. The paper is moistened with water and folded into the cylinder, the diameter of which reaches about 100. 150 millimeters, and only after that proceed to “edit”. And before installing the knife, it is important to make sure that the weight of his shoulders remains the same, otherwise (in case of unbalance), extremely undesirable vibration may occur. To check the balancing, at first a smooth bar is horizontally clamped horizontally, and then, through the hole located in the middle, the blade is put on it and also try to install it horizontally, observing its behavior. one shoulder should not noticeably pull the other. If the balance is not observed, then a little more metal is grinded from one of the shoulders. And only after that you can again install the sharpened knife on the lawn mower!

For lawn mowers is produced

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The electric engine works on electricity and has a limited radius of operation and depends on the length of the wire. Allows the operator to work only in dry weather to avoid electric shock. Be sure to clearly ensure that the cable is not cut by accident, because the knives are very sharp and rotate at a huge speed.

The most mobile lawn mowers with a gasoline engine. Their work radius and electric shock will not occur. The main thing here is. observe the correct angle of inclination of the lawn mower so that the fuel evenly enters the engine, this angle is no more than 30 degrees. Cool slopes should be rendered, carefully assessing the surface of the mowing slide in order to protect the motor from damage as much as possible.

We carry out the following sharpening work:

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Despite the fact that the laces of the lawn mowers are made of high.quality steel, from time to time their sharpening has to be updated. Fortunately, for this you do not need special skills and equipment, and today we will tell you how to sharpen the lawn mowing knife yourself without worsening the quality of the metal.

You can cut off excess grass from the lawn even if the edges are obviously bluntly bluntly at the mowing knife. However, at the same time, the shoots will be spaced in the longitudinal direction, turning into a fringe. A few days after the mowing, the grass will become terrible and will hurt a few more weeks. The cut should be even and neat, then it will drag on in just a few hours and the lawn will always be juicy-green. This requires the knife to be sharpened almost perfectly.

Left: grass cut off with a blunt blade of the lawn mower. Right: grass cut off with a sharp blade

How to remove a knife from a lawn mower

Before proceeding with a partial disassembly of the lawn mower, you need to protect yourself and it. If the device with an electric drive is enough to turn off the network, then gasoline lawn mowers require preliminary preparation. First of all, you need to remove the cap from the spark plug. The following should be excluded fuel leaks, that is, either drain the tank, or put a hermetic rubber membrane under the lid and block the fuel valve. The lawn mower should be turned over only towards the handle, unless otherwise specified in the instructions for operation. Before turning the law mower, do not forget to squeeze the hose of the exhaust gas exhaust so as not to pour oil.

The lawn mowers use knives of different configurations. In the simplest case, this is an ordinary two.lobed plate of complex shape, however, the knife can be composite. the upper blade is designed to mulch the mowed grass. There are also four.lobed knives, which can be both composite and at the general base.

The knife can be mounted either with one bolt in the center through a style washer, or two bolts with landing on a central hole or pin. In any case, the thread on the bolts is right, respectively, you need to unscrew counterclockwise. To block the shaft from rotation, substitute a bar rested in the ground under a knife. It is advisable to remember or outline the position of the blade (I), so as not to confuse anything when reverse assembly. Temporarily make the twisted bolts in free holes.

How to remove a knife from a lawn mower

Before proceeding with a partial disassembly of the lawn mower, you need to protect yourself and it. If the device with an electric drive is enough to turn off the network, then gasoline lawn mowers require preliminary preparation. First of all, you need to remove the cap from the spark plug. The following should be excluded fuel leaks, that is, either drain the tank, or put a hermetic rubber membrane under the lid and block the fuel valve. The lawn mower should be turned over only towards the handle, unless otherwise specified in the instructions for operation. Before turning the law mower, do not forget to squeeze the hose of the exhaust gas exhaust so as not to pour oil.

The lawn mowers use knives of different configurations. In the simplest case, this is an ordinary two.lobed plate of complex shape, however, the knife can be composite. the upper blade is designed to mulch the mowed grass. There are also four.lobed knives, which can be both composite and at the general base.

The knife can be mounted either with one bolt in the center through a style washer, or two bolts with landing on a central hole or pin. In any case, the thread on the bolts is right, respectively, you need to unscrew counterclockwise. To block the shaft from rotation, substitute a bar rested in the ground under a knife. It is advisable to remember or outline the position of the blade (I), so as not to confuse anything when reverse assembly. Temporarily make the twisted bolts in free holes.

Cleaning and editing

When the knife is removed, it needs to be cleaned the first thing from adhering dirt and hardened herbal juice. The easiest way to do this is to use a metal kraitsy. The knife strip should be clean from all sides: not to a metallic shine, but without the smallest sticky fragments.

Often, due to the entering the working area of ​​solid items, such as stones and chips, the blade is very noticeably deformed. Most of the blades themselves are not straight, but the cutting edge and strip 10-15 cm from it should be examined for the presence of local tubercles and curvatures. This is done using a short even line.

You can straighten the blade with an ordinary hammer, in which the edges of the box are slightly rounded. The knife is laid on an even massive support (anvil), then the correct shape is given with weak blows of the metal. You need to rule the knife, starting from the edges of the curved area, gradually moving to the center. The curved body of the blades is a small problem, but it is very important that the cutting parts are straightened into one straight line for a trimmer. You also need to check the casting blades that often extend from the blow. If the blades are bent at different corners on different shoulders of the knife, this will worsen the air flow and the mowed grass will not be mulched properly.

Reasons for removing a knife

Among the common reasons for removing or replacing the cutting element are as follows:

When the knife swept, bent or deformed, the lawn after the haircut looks untidy. Comfortable sharpening will correct the situation.

Professionals advise to carry out the procedure once a year. It is better to do this in the spring, before starting work. If the cutting elements dull faster, then sharpen them more often.

If chips, cracks are visible on the blades, or it is very stuck and has become thin, then in this case a replacement is necessary. Sharping such a tool does not make sense. In addition, the blade can break and fly out from under the case of the car at any time, injuring people or animals that were nearby. Such a device can also lead to engine breakdown. Change the element is allowed to be a similar model. The characteristics of the knife are indicated in the instructions.

If there is no suitable product in the store, you can always purchase a lower length blades. In this case, a little more time will go to put the lawn in order than before. But this is not a problem compared to the fact that the inappropriate knife is sometimes impossible to securely fix on garden technology. Then the way out. knives for lawn mowers are universal. These are the blades, which includes adapters, bolts, washers, etc. The knives themselves have several mounting options. As a result, the cutting elements can be fixed on completely different models.

On a professional machine

This option is more suitable for hairdressers, the working tool of which requires regular. at least 4 times a year. and high.precision sharpening. over, only a special machine can provide the high quality of this process, which significantly reduces the time for this procedure.

The algorithm of actions in this case looks like this:

• Remove the knives from the trimmer for the grass;
• We cover the grinding disk peeled from dust and dirt with an uniform layer of abrasive pasta;
• we fix the knife on the magnetic holder with a cutting edge down;
• run the machine at a certain speed (indicated in the instructions);
• We bring the knife to the circle and begin the sharpening process, smooth movements of the blade, whose teeth should be directed against the movement of the grinding disk, from the edge to the central part.

The main disadvantage of this method is the high cost of a professional machine and consumables.

Varieties and sizes

Consumables for lawn mowers. knife (fishing line for trimmer, cord) and drive belt. Types of knives used in modern braids. rotary and cylindrical. The second is also called drum or spindle. The sizes of cutters for lawn mowers are mainly limited by the spread of external diameter values ​​of 33–51 cm. Specific dimensions, for example, 40 and 46 cm, you can choose in any store. In the user guide to each of the models of lawn mowers, the recommended size is indicated. Taking a lesser knife in diameter, you will reduce labor productivity due to a narrower “rut”, which is pumped out in the grass, that is, the number of rows, passing by a mowing, will increase. and you are unlikely to move faster.

The knife will “put” the engine turning too much, which will lead to greater wear of the last.

Finally, the material of the cutter is crucial in terms of security. Most knives are made of stainless steel, but plastic knives are also found. The fact is that when the cutter rushes on a large stone, then the wreckage of the steel can hurt you with a ricochet. The blow of the plastic fragment is much more harmless. unless it gets into the eye. Plastic knife. the choice of owners of mowers with a curved flexible shaft. A universal knife for lawn mowers not only cuts grass and shrub, but also crushes them. due to a larger number of blades (up to 8). Finely chopped grass will fit as a top dressing (mulch) for the lawn.

On a professional machine

This option is more suitable for hairdressers, the working tool of which requires regular. at least 4 times a year. and high.precision sharpening. over, only a special machine can provide the high quality of this process, which significantly reduces the time for this procedure.

The algorithm of actions in this case looks like this:

• Remove the knives from the trimmer for the grass;
• We cover the grinding disk peeled from dust and dirt with an uniform layer of abrasive pasta;
• we fix the knife on the magnetic holder with a cutting edge down;
• run the machine at a certain speed (indicated in the instructions);
• We bring the knife to the circle and begin the sharpening process, smooth movements of the blade, whose teeth should be directed against the movement of the grinding disk, from the edge to the central part.

The main disadvantage of this method is the high cost of a professional machine and consumables.

Removing the descents

If the knife has not sharpened for a long time, excited chips will be likely to appear on it with a high probability. They need to get rid of them, withdrawing the edge of the blade at an uniform angle along the entire length of the cutting area. Please note that there may be several edges on each side, in this case, several cutting planes form a lawn mower.

Lugus knives have unilateral sharpening, the descent of which is usually turned upside down. To derive the descent at the right angle, you should use an electric sharpener with a carborne stone, and in the absence of such a small file. It is very important to remove metal evenly from both blades. Therefore, keep the same pressure and at least approximately count the number of passages of the sharpener.

Small deviations of the angle of sharpening are not critical, but the smoother the descents will be displayed, the more the resource of the knife will be. When deriving the shape of the blade, it always moves to the grain in order to avoid the formation of large burrs and mix. You should not use a corner grinder for pre.sharpening. overheating can worsen the quality of the metal. However, you can install a petal or plate disk for sandpaper on an angular grinder.

Rules for installing a knife

After the knife is subordinate, it should be put back. Installation of cutting elements is not a very difficult matter. The main thing is to follow the rules:

• Determine in what position the knife was before.
• In the same position, fix it with a new or old bolt, washers and nuts.
• You can’t pull the nuts too much. This will lead to deformation of the cutting device.
• During operation, you should put thick gloves in your hands. It is important to remember that the updated blades are sharp.
• After the mower is on the ground in its usual position, it is not recommended to turn it on immediately. It is necessary to wait an hour so that glass oil is from the walls of the crankcase.

With the wisdom of removing the cutting element from the lawn mower, even a novice gardener can figure out. However, with independent sharpening, you should be extremely neat so as not to get hurt and not remove too much metal, thinning the knife.