How To Change A Knife On A Trimmer Video
The trimmer is the most common unit used for cutting grass and cutting small bushes. This unit is notable for its ease of maintenance, simple operation during operation, and even women can cope with it due to its low weight. It is no secret that for the high-quality performance of mowing grass, the correct selection of cutting tools is required. As the last in trimmers, special cutting nozzles (discs, knives) or trimmer heads with fishing line inside are used. Nozzles and fishing line is a consumable tool, but if the knives can be sharpened, then when the fishing line is used, its replacement is required. In this article, we will describe in as much detail as possible how to replace the fishing line correctly.
Types of trimmer heads
The grass mowing head is a cylindrical body in which a reel (bobbin) with a fishing line (cord) tucked into it is inserted. This design can be installed on both gasoline and electric trimmers. The heads differ in the method of filling and feeding the cord and there are 3 types.
- Automatic. Cord feeding is performed after the user reduces engine speed. Although automatic feeding of fishing line is convenient if large volumes of work are performed, such bobbins have one drawback. High thread consumption.
- Semi-automatic. The use of this type of head does not require the user to perform complex manipulations. The principle of their work is arranged so that the cord is automatically extended at a time when the device is operating at full speed. It is enough to lightly tap the head of the trimmer on the ground (this removes the blockage of the cord), and thanks to the centrifugal force, the fishing line is pulled out of the bobbin, and then cut to the desired length with a knife located on the protective cover.
- Hand held. To lengthen the cord requires stopping the machine, after which the fishing line is pulled by hand.
Based on the above, semi-automatic bobbins are the best option. It should also be noted that the coils for the trimmer are single-string (used only for trimming grass) and double-string, which are used to mow tall grass and small, with thin stems of shrubs.
How to remove and disassemble the coil
Before starting the process of replacing the cord, users of trimmers need to remove and disassemble the coil. Consider how to do this.
The mowing head of the trimmer consists of several parts: a casing, springs (not on all models), bobbins with cord and covers.
In trimmers, 2 options for attaching the mowing head are most often used.
Option number 1
To remove the trimmer head, you will need it complete disassembly.
- To remove the cover that covers the inside of the head, you must press on the latches (latches) located on both sides of it.
- After removing the cover, you will see the spool, which must be removed from the housing. In some coils, a spring is installed under the bobbin, which must be carefully pulled out so as not to lose it in the grass.
- After removing the bobbin, in the center of the case you will see a screw with a slot for a Phillips or flat head screwdriver. It is possible that there may be a bolt under the hexagon or nozzle “asterisk”.
- Using a screwdriver, selecting the required bit (nozzle), you need to unscrew the bolt (counterclockwise).
- After removing the fasteners, grasp the body of the part and, swinging it in different directions, remove it from the gearbox shaft.
Option number 2
In this embodiment, the head is screwed onto the gear shaft. To take it off, you need this lock the shaft. To do this, in such trimmers, for example, in Huter and Champion devices, a hole is provided through which you can insert either a thin screwdriver or a metal rod.
So, to remove the bobbin, follow 2 simple steps.
- Insert a screwdriver into the hole and lock the shaft.
- Grasp the head housing and start twisting it clockwise. Turn in this direction for the reason that the thread cut on the shaft is left.
Fishing line winding algorithm
Depending on which trimmer model is used, the type, thickness and length of the fishing line are selected. The diameter of the cord can be from 1.2 to 4 mm. It is not difficult to guess that the thicker you fill the cord, the more rigid and thick grass it can cut.
There are 3 ways to find out what diameter of fishing line can be used on your mower.
- View information about the thickness of the cord in the instructions for the device.
- Look at the bobbin itself. It can be marked with information about the possible diameters of the fishing line.
- Insert the fishing line into the outlet. If it easily passes into it, then a cord of this diameter can be used.
The line is wound on a reel located in the mowing head. Therefore, you must first open it (this was discussed above). There are 2 ways to wind the cord.
In order to correctly determine how many meters of fishing line is needed for a particular reel, it is necessary to wind it on a bobbin so that the coil does not exceed the diameter of the sides. If the fishing line peeks over the edges of the reel, you cannot insert it into the casing. After you have decided on the length of the material, it must be loaded into the bobbin, so do the following.
- Necessary fold the fishing line in half, so that one end of it is 10-15 cm longer from the other.
- Please note that the bobbin is divided into 2 parts by the central side, from which charging begins. Find a groove on it and insert a cord bent in half into it, with a little effort.
- It is very important to determine, in which direction is the fishing line wound to the reel. If you look closely, you can find an arrow on the bobbin or an inscription with an arrow indicating in which direction the winding should be carried out. There are times when there is no arrow on the reel. In such a situation, you can look at the arrow drawn on the mowing head and wind the cord in the opposite direction.
- Winding should be carried out carefully, coil to coil, with maximum thread tension.
- After laying the cord is completed, you will need to first fix the short end of the fishing line, inserting it into a suitable diameter groove on the side of the reel.
- The second end, the one that is authentic, is mounted in a groove on the opposite side of the bobbin.
- After fixing the fishing line, cut off its ends, leaving allowances of about 10 cm.
- Next, you need to install a seasoned coil in the mowing head. To do this, by inserting and pulling the thread into the outlet openings of the head, place the bobbin in the casing, and then, after applying the required force, pull the fishing line out of the fixing grooves and tighten it.
- Now you can put on the cover and fix it with latches.
In some coils, a second way of securing the cord is provided: 2 pieces of thread can be charged, instead of one folded in half. Replacing the fishing line occurs according to the following algorithm.
- Before changing or charging a new thread into a bobbin, determine how many meters it will be required in the manner described above.
- Bend one end of the cord in the form of a hook.
- Locate the hole at the bottom of the bobbin to secure the fishing line, and insert the end of the thread bent in the loop into it.
- It is required to wind the cord according to the direction of the arrow to the required level not exceeding the diameter of the coil.
- Do the same for the second bobbin slot.
- Assembling the head is no different from the method that was given when refueling the bobbin with a doubled piece of fishing line was considered.
For Shtil lawn mowers There is a very simple and quick way to replace the fishing line without disassembling the mowing head, which you can familiarize yourself with by watching this.
The ends of the cord protruding from the holes in the casing can be cut to the required length when the part is installed in the trimmer. There are two ways to do this:
- Turning on the trimmer (during rotation, the ends of the fishing line will be cut about a knife fixed for this purpose on the protective cover);
- By cutting off the excess ends with scissors so that they do not touch the housing body.
The second method is used if it was necessary to put a cord of large diameter, and a cutter cannot shorten it.
If the thread was charged into the mowing head, but the length of the protruding ends of the cord is insufficient, then they must be lengthened before starting the machine. This applies to the head with manual adjustment. However, there are cases when using a semi-automatic mowing head, when due to the insufficient length of the protruding ends of the cord, they do not automatically extend. In this case, it is necessary to turn off the unit (it is absolutely necessary to pull the plug out of the socket on the electric apparatus), manually press the button located at the bottom of the part, and pull out a little fishing line. After this procedure, the cord will again be able to extend due to centrifugal force, if you set the maximum spindle speed.
What can be used instead of fishing line
Many users of trimmers are wondering: what can replace the default cord used in this kind of apparatus? They begin to conduct unsafe experiments, installing metal or copper wire, metal cables or strings, as well as ordinary fishing line in the mowing head.
If set instead of fishing line metal cable, then the trimmer turns into a dangerous device not only for the user, but also for others. This fact is explained by the fact that during operation of the unit, the steel cable will gradually work, its ends will unravel, and small pieces of wire will fly apart in different directions at high speed.
And if you accidentally hook your own or someone else’s foot while operating the machine with a steel cable (wire), then a strong and deep cut of the tissues, and in some cases amputation of your toes, is provided. It is not in vain that the manufacturer uses nylon for these purposes, since it is quite light and durable, and when detached it does not fly away and cannot cause injury.
Use fishing line in the trimmer instead of the standard one, of course, it is possible, but this will add you unnecessary trouble, because it wears out quickly, breaks, mows slowly and is not suitable for cutting hard grass. In addition, when carrying out work, a lot of time is lost in order to replace a broken tool more than once.
In practice, the installation of an ordinary fishing line is justified if the user is going to mow the grass near the fence, especially if he is from a netting net. In this case, in order to protect the standard, and sometimes expensive cord from wear, it is changed to a fishing line, which is not AL-KO. Usually, in order to change the cord to the fishing line, it needs to be selected with the greatest thickness. 2-3 mm.
Replacing fishing line with a disc or knife
When refining a garden plot, park areas and other places where it is necessary to mow various kinds of plants, it is often necessary to change the cutting tool in the trimmer. This is dictated by the fact that the standard cord installed in the mowing head can only cope with herbs. But when a shrubbery or young shoot of trees appears on the way of the worker, the fishing line cannot cope with such a task, and its change to a more effective cutting tool is required.
Manufacturers of trimmers provided for such situations, and supplemented their products with a mass of nozzles in the form of knives with several “petals” or in the form of disks similar to circular saws.
If you replace the fishing line with a knife with several “petals”, then with such a tool you can mow both tall grass and plants with thick and dry stems. And changing the fishing line to the disk, the user has the opportunity to lawn mowers to cut shrubs or small trees.
Knives and wheels are installed according to the following algorithm.
- The first step is to remove it by locking the shaft, the mowing head (turn clockwise) or the nut with the boot if the unit has not yet been used.
- Set the saw or cutting knife so that they are put on a small ledge (bushing).
For a better understanding of the tool change process, you can watch this.
Fishing line problems
Users of trimmers, both gasoline and electric, sometimes have problems with the cord. “Advanced” owners of mowers can easily cope with the difficulties encountered, understanding why this is happening, and for beginners, this is a problem that does not have a rational explanation. But in fact, everything is solved quite simply. The most common problems that happen with fishing line are as follows.
If the line is often torn, the following reasons can cause it:
- Stones, small branches and other solid obstacles come across in the grass;
- The user mows the grass right next to the fence, and if it is mesh, it breaks the “antennae” even faster;
- Poor cord quality (recommended to purchase high-quality);
- The outlet openings in the mowing head are worn out, due to which the fishing line is erased against the sharp edges of the bushings and breaks off (a complete replacement of the part is required).
High cord consumption
Basically, a cord ends quickly if often pounding the ground with a semi-automatic head or push it down hard. The reel is unlocked, and the fishing line, lengthening, is cut with a knife. Another reason that the cord ends quickly is the improper operation of the machine with an automatic head: when mowing, the user often drops engine speed. But as we remember, the automatic head is designed so that it is with each decrease in speed that a new portion of fishing line is fed, so it is quickly consumed.
The thread does not hold
It happens that the thread is unwound if in a semi-automatic head the spring has loosened. The fishing line is constantly extended and cut with a knife mounted on the casing, which increases its consumption. To check this, remove the cover and turn on the unit. If the fishing line “climbed”, then you need to replace the spring.
Fishing line crashes
The reason that the cord unwinds after starting the unit can also be the weakening of the spring inside the head. In addition, there are times when the mowing head scatters when the unit is turned on, and the spring installed in it is lost. Inexperienced users do not notice the absence of a spring and assemble this unit without it. Therefore, the cord does not hold, and flies out under the influence of centrifugal force.
Cord not feeding, coil not spinning
An automatic or semi-automatic head should feed the line without stopping the unit. But if it does not come out, then the reasons may be the following:
- Incorrectly wound fishing line in the reel, because of which the latter does not spin;
- The cord is wound unevenly, and the thread can get stuck between turns (the thread should be wound carefully, turn to thread, without distortions);
- Too short ends of the thread come out of the holes, as a result of which there is not enough centrifugal force to extract them, and the fishing line is not supplied (it is recommended that you always adjust the cord length before starting the unit, pulling it slightly);
- The fishing line stuck together (to be discussed later).
The thread sticks together
This trouble is most often due to use of low-quality cord. When the machine is operating, the trimmer head heats up, and the poor-quality fishing line in it melts, sticking together. Also, sintering of threads occurs when a fishing line meets a solid obstacle. In this case, a sharp braking of the cord occurs, after which it is pulled into the head, where it is attached. Some owners of the units recommend lubricating the cord with mineral oil or spraying it with silicone spray after winding on a bobbin. Others advise winding less thread on a bobbin. But it is better to immediately buy a quality product, in the manufacture of which the manufacturer took into account the factor of overheating of the head, and the thread will not stick together.
If the disc on the trimmer is used regularly, it needs to be removed from time to time and sharpened or replaced with a new one. This part can be made of metal or plastic, have a different number of blades, but the replacement process remains the same. Over, this procedure is similar for technology from different manufacturers, whether it be Carver or Huter, but slight differences are possible. Changing the knife on the trimmer is quite simple if you follow the safety precautions and know the correct procedure, the description of which can be found in the user manual. The entire replacement process step by step, as well as the method of self-sharpening knives, will be described in this material.
When the use of knives is relevant
When using lawn mowers in suburban areas, the most popular nozzle is fishing line. It has a low price, suitable for different trimmer heads, safe to use. The disadvantage of using fishing line is that it is convenient only for mowing low growth. In other situations, the string immediately becomes clogged, regardless of whether a gasoline or electric trimmer model is used. In addition, vegetation is wound on the spindle, which creates significant resistance on the shaft and leads to its breakdown. It can also provoke a failure of the piston system in lawn mowers or a burnout of the motor in trimmers.
Therefore, for mowing tall or hard vegetation, various nozzles are used. So, for harvesting tall and rough grass, thin shoots of trees and shrubs, it is better to install and use a disk. This nozzle clogs much less often, which contributes to greater wear resistance of the equipment.
Features of lawn mowing discs
Knife disks are produced in plastic and metal, as well as in various shapes to perform diverse tasks.
- Two-, three- and four-blade Knives with pronounced blades are used for mowing grass and overgrown trees. However, they are not suitable for harvesting hay, as they chop the shoots by chopping them several times.
- Massive four-bladed discs are intended not only for clearing the ground from grass, but also for mowing hay. They prevent multiple cutting of the shoots, thereby making them suitable for harvesting for the winter.
- Perimeter Cutting Blades relevant for bevel reeds and reeds. Such knives are very heavy. This is a necessary quality to cut through thick stems.
- Professional saw tooth discs for brush cutters and lawn mowing, small trees and bushes can be cut.
As an alternative to metal discs, plastic knives are used. They do not need to be tightly mounted in the head, but they rotate as a result of centrifugal force. The durability of plastic knives is high, so the service life is quite long.
Order of installation of a disk on the trimmer
Installing the knife on the trimmer is very simple. To do this, use the complete key that disconnects the cutting nozzle and the pin blocking the gearbox. The procedure is as follows.
- First of all, you should disconnect the electric trimmer from the network, gasoline. Just drown. Detach and remove to one side the protective cover.
- Next, you need to combine the holes on the gearbox and shaft to insert a pin into them and lock the drive.
- If a spool with fishing line was used, it must be unscrewed clockwise.
- Then you need to find a nut to tighten the knife.
- The next step is to install the knives. Trimmers often wonder which side to put the disc on. This should be done so that the markings with numbers and letters are on top.
- Then you need to put the boot on top, and above it. The fixing nut, which must be tightly tightened with a wrench.
- The last step is to install the protective cover.
As you can see, the procedure is very simple and the same for many brands, whether it is the equipment of the company “Stihl” or Husqvarna.
Disc Selection Criteria
You need to choose a plastic or metal knife, considering the area of the plot to be processed, as well as the type of trimmer. Electric or gasoline. The number of blades will depend on which shoots you need to remove with the tool. You can select the desired shape of the disk, the number of blades and the material of manufacture using the instruction manual of the device. Usually it prescribes which cutters it is recommended to use to solve certain problems.
It is not recommended to put metal knives on electric braids, since the design features make their use dangerous for the user. This is due to the curved shape of the rod, the lack of stops on the handles, as well as the high speed of rotation.
Flexible Trimmers in terms of safety, plastic knives should be used. Their purpose is mowing soft grass, dead wood. While metal discs do an excellent job with tall, dense, hard shoots, shrubs, and also shoots of trees.
The number of blades is important in solving diverse problems. So, for chopping grass, two or three pieces are enough. For haymaking, it is necessary that the disk had from four to eight blades. To destroy small shoots of trees and shrubs, instead of lobes, there should be a large number of small teeth on the disks.
Regardless of the quality of the disc, over time it becomes dull and begins to cut grass poorly. If the knives are still relatively new, and replacement is not practical, you can sharpen them with your own hands.
To sharpen disks, you must:
- Disassemble the trimmer, remove the knives;
- Carefully inspect the disk. If cracks are detected, it is better to replace the part with a new one, since its further operation is unsafe;
- Bent blades can be gently bent with a hammer;
- Given the size of the disk, you need to choose the right file for metal, this will provide more convenient work;
- At an angle of 30 ° equally sharpen all the upper cutting edges of the disks;
- Reassemble the trimmer in the reverse order.
For sharpening the disc, you can use the emery machine at low speeds, setting up a grinding wheel with medium grain. Through such a tool, the process will move much faster. For safety, you need to wear gloves on your hands, and a face mask or glasses on your face.
So, for grass mowing on gasoline and trimmers, plastic and metal discs of various shapes and with a different set of blades are used. They are selected in accordance with the type of work performed and the size of the cultivated area. If the knives on the mower are dull, they are easy to sharpen or change yourself. Despite the simplicity of the procedure, you need to be careful and remember about safety so as not to be injured by negligence or damage the equipment. A more detailed description of the replacement of knives for a specific trimmer model can be found in the operating instructions or on the manufacturer’s official website. For clarity, the general process diagram is shown in the.
Trimmer STAVR TE-1700R on Yandex Market
Makita UR3502 trimmer on Yandex Market