How to Change a Disc on a Trimmer

If the disc on the trimmer is used regularly, it needs to be removed and sharpened from time to time 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 breakage. It can also provoke a failure of the piston system in the brushcutters or burnout of the motor in the trimmers.

how to change the disc on the trimmer

Therefore, for mowing tall or hard vegetation, various nozzles are used. So, for harvesting tall and coarse 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.

On a note! Due to the fact that the engine of trimmers and battery models is less powerful than on gas mowers, so the use of discs is more relevant for gas mowers.

Features of lawn mowing discs

Knife disks are produced in plastic and metal, as well as in various shapes to perform diverse tasks.

  1. 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.
  2. 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.
  3. Perimeter Cutting Blades relevant for bevel reeds and reeds. Such knives are very heavy. this is a necessary quality to cut through thick stems.
  4. 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 fixed 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.

On a note! The advantage of plastic disks is that, having hit an insurmountable obstacle, they bounce off and there is no repeated contact.

Order of installation of a disk on the trimmer

Video: How to Change a Disc on a 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.

  1. First of all, you should disconnect the electric trimmer from the network, gasoline. just muffle. Detach and remove to one side the protective cover.
  2. Next, you need to combine the holes on the gearbox and shaft to insert a pin into them and lock the drive.
  3. If a spool with fishing line was used, it must be unscrewed clockwise.
  4. Then you need to find a nut to tighten the knife.
  5. 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.
  6. Then you need to put the boot on top, and above it. the fixing nut, which must be tightly tightened with a wrench.
  7. 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.

On a note! If the owner of the device wants to replace the disk back with a fishing line, you can install a reel with it in the same way.

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 growth needs to be removed 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.

Important! A straight boom ensures safe use of the trimmer at times when the disc rotates against an obstacle. In this situation, it bounces back. towards the person, so a curved structure can cause injury.

On Flexible Bar 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 on the disks, there should be a large number of small teeth.

Disc sharpening

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.

Important! Only those discs on which there are no soldering from solid materials are suitable for sharpening. Such parts are thrown away, and new ones are acquired instead.

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.

To sharpen 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 on their own. 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 to 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 video.

The best trimmers

Huter GET-400 trimmer on Yandex Market

Trimmer STAVR TE-1700R on Yandex Market

Makita UR3502 trimmer on Yandex Market