How to Put the Knife On the Trimmer Correctly

With the advent of summer, many owners of household plots are concerned about the issue of how to put a knife on a trimmer. No less relevant are the questions of why and when it is advisable to replace the fishing line on the lawn mow with a more durable cutting element. In our article we will try to make out all this and give useful recommendations to summer residents.

  • Why you need to put a knife on a trimmer
  • What knives to put on the electric and lawn mowers
  • How to put the knife on the trimmer

Why you need to put a knife on a trimmer

The trimmer with a knife mounted on it is most convenient to use for more comfortable mowing of tall and coarsened grass in the country. The line on the lawn mowing in such cases can not cope. Thin breaks very quickly. Using a thick 2.3 mm cord or homemade rods with cables causes the vegetation to wind up on the spool. This increases the load on the engine. As a result, the piston group and other moving parts of the unit wear out very quickly.

How to Put the Knife On the Trimmer Correctly

If the mowing of the weeds is carried out with an electric trimmer without a knife, only fishing line, even if it is thick with a curly section, the problem cannot be solved. There is always a risk of overheating the motor and damage the flexible shaft. And it’s all about the big torque of the electric motor. The grass wound on the spindle creates strong resistance to the shaft, resembling a speedometer cable, which does not withstand and twists.

In order to protect the equipment from premature wear, manufacturers have provided the ability to install special knives on trimmers. The design and shape of existing cutting elements makes it easy to cope not only with coarsened and overgrown grass, but also successfully deal with young shrubbery.

What knives to put on the electric and lawn mowers

Before buying and putting a knife on a lawn mow, we will find out what they are and in which cases they are used. Today, manufacturers offer consumers a large number of types of these consumables. In general, all cutting tools designed for mowing grass can be classified:

  • By the type of material from which it is made;
  • In the shape of its cutting blades.

The main material for making trimmer knives can be plastic or metal. The use of such consumables is largely dependent on two parameters:

  • Type of lawn mowers;
  • Square mowing.

For safety reasons, manufacturers do not recommend placing steel knives on electric trimmers. Almost all lawn mowers powered by mains and battery are equipped with plastic blades. Depending on the manufacturer, they can be of a single disc-shaped design with several blades or in the form of a special mowing head for the installation of removable plastic blades.

Straight bar at gas trimmer and curved at electric

To put a metal knife on an electric trimmer does not allow its design features.

  1. The curved rod of the unit reduces the distance from its working part to the legs of the mower. If the blades collide with a stone or other solid object, the braid is thrown to the feet.
  2. The high torque that we mentioned above, in the event of a collision of a metal knife with a solid object, transfers a large load to the flexible shaft of the trimmer and its motor. What causes their premature failure.
  3. The handle of an electric braid most often does not have a restrictive bar acting as a stop. Which does not exclude injury to the legs.

It is these features that allow the use of exclusively plastic knives on trimmers with electric motors. In a collision with an obstacle, the blades are destroyed, thereby protecting the legs of the mower from possible injuries.

The use of metal knives only on gas trimmers is also due to design features.

  1. The direct design of the bar increases the distance to the legs, which ensures complete safety.
  2. Convenient U-shaped and J-shaped handles allow to hold the tool firmly. D-shaped lawn mowing arms are equipped with a limiter resting on the leg of the pigtail, which does not allow the head to be allowed to close when the cutting disc meets a solid obstacle.
  3. The clutch of the gasoline engine allows you to smoothly gain speed to the optimum level. And when the blade collides with a hard surface, it can absorb part of the impact.

Thus, gas trimmers with an installed metal knife are best used in large areas. They will successfully cope not only with tall coarse grass, weeds, burdocks and nettles, but also shrubs, as well as young trees.

The shape of the blade blades placed on the trimmer does not affect the quality of the work performed. Speed ​​does not depend on them either. Triangular, trapezoidal, rectangular shapes are all the marketing ploy of manufacturers.

How to put the knife on the trimmer

Putting a knife on the trimmer is not so difficult. The manufacturer supplies his tools with a special pin that allows you to lock the gearbox and a key with which you can unscrew the spool with fishing line. The most important thing to observe when changing the cutting elements is the safety precautions and the assembly sequence of disassembly.

The algorithm for installing the knife on the trimmer is as follows:

  1. Remove the protective cover;
  2. We block the drive. To do this, combine two holes. in the shaft hub and in the gear cup. After combining them, insert the pin into the holes;
  3. We turn off the spool with fishing line or the fastening nut holding the boot (clockwise, if the trimmer has not been used) clockwise from the hub;
  4. Next, install the cutting knife, so that the slots on the hub washer coincide with the recesses in the hole of the cutting disc;
  5. Install the boot;
  6. We twist the fastening nut (counterclockwise) while holding the locking pin;
  7. Tighten it using a pipe wrench;
  8. Return the protective cover to its place.

Video: How to Put the Knife On the Trimmer Correctly


As you can see, there is nothing complicated. Now you can safely proceed to mow the weeds on the site.

In the age of modernization, the market is rich in various construction tools that simplify and speed up the work process. Also, not a single repair or construction is complete without an electric planer. Each tool has additional components, but at the plane these additional elements are knives, with which the tree is processed. Such knives are double-sided and come in a complete set of two pieces. If the cutting elements began to take off chips poorly, it means that they have come to an inoperative state, and they need to be sharpened.

But, before you begin to disassemble the tool, you need to know how to put the knives on an electric plane. In this regard, it is important to study in detail the principles of analysis of the planer.

Installation of knives: recommendations

The cutting elements are mounted on a planer drum that rotates. The purpose of knives is planing of the upper layers of wood in the process of processing products. This design is equipped with one or two cutting elements. The last knives are rotary, if necessary their position is easy to change if one of the sides is dull. Knives for electric planes are made of tungsten carbide or tool steel. Products made of steel can be re-sharpened.

The blades have a different configuration and are divided in shape:

  1. Direct. they are installed when sampling quarters and when processing small parts.
  2. Rounded. used when planing wide sections of parts, since the transitions between planed fishing lines are done smoothly.
  3. Wavy. like knives are used when imitating antiquities on wood.

Scheme of options for sharpening a knife of a planer: a. on a donkey, b. on a grindstone, c. the position of the chamfer of the cutter blade when sharpening on a donkey, d. sharpening on the disk of a grindstone using a stop device.

Before you start working with an electric planer, you must make sure that the knives are installed correctly. If any errors were found, then you need to correctly set the knives on the electric plane. The cutting part of the element should be parallel to the bottom of the planer and protrude slightly upward. In order to be able to determine the correct adjustment of the knife, it is enough to turn it upside down and raise the plane at eye level.

Typically, the cutting part of the knife protrudes 0.5 mm above the sole. But the sherbel, which serves as the first roughing planing, its cutting edge, is produced by at least 1 mm. Adjustments can be made without problems. At the same time, it is important to turn the small and large adjustment screw to the right and left until the cutting part snaps into place. These screws are located on the back of the platform designed for the electric knife.

After all the manipulations, the knife is installed in the tool itself and fixed with centering fasteners on the upper plate. If the electric planer is new, then, as a rule, his knives are adjusted, but when using the tool, the settings go astray. In this regard, if the planer did not work for a long time, it is recommended to pre-adjust it. It is also important to remember that immediately after setting up, it is not recommended to perform work immediately on the parts, without first having tested the tool on an unnecessary board.

Classification of modern knives

Planers of foreign production, for example, by Skil, are equipped with standard 82 mm knives, the common name for them is “records”. If you choose inexpensive and durable options at the same time, the craftsmen advise Zubr knives, which are made of carbon steel. Such products are universal, as they are suitable for most planers of various foreign manufacturers. They are used even in well-known tools like Bosh and Makita.

Scheme of the angle of sharpening a planer.

There are knives made specifically for individual models of planers. Quite popular electric planers “Interskol” and “Baikal” have individual knives, whose width and thickness are greater than that of conventional plates. Due to their parameters, they have higher qualities and are strong, which means that if you suddenly get a nail or a knot when working with an electric planer, the knife will not break, and the nicks on it can easily be removed with emery.

Such knives usually have a width of about 1 cm, and they are visually different from their counterparts. The length of such knives is 82 and 102 mm, and it corresponds to the planer model. If they become dull, they can be sharpened without problems even on their own.

There is also another type of knife for electric planers. They are made wide and thick and equipped with mounting holes. This model of knives is extremely specific, as they are suitable only for certain models. These models include Rebir planers, they have a capacity of 2000 watts. A distinctive feature of these knives is their large thickness and power, and its width can reach 110 mm.

How to replace electro-knife knives?

Electric planer knives require a special approach, and very high demands are made on them. When the knives are blunt, this can be determined with the naked eye. For this, the chamfer is simply explored in the light. It needs to be considered by turning around the incisal edge. If at the end of the chamfer, a sanded strip with a thickness of thread was formed, then the cutting part became dull. The knife is sharpened at an angle of 30 degrees.

Modern manufacturers began to produce knives with rotary blades. This is convenient: when one of the blades becomes dull, they simply turn it over.

The device is a modern electric planer.

In an electric planer, cutters are installed in a special knife holder. It is located in a conical groove and is clamped using three nuts. The height of the protrusion can be adjusted with screws that are located at the edges. When the element is removed, the nuts loosen, the screws tighten, which allows the holder to be pulled out of the groove.

Next, a punch is selected for the size of the product and with its help it is knocked out of the groove. The next step will be to replace or turn over the element, which is neatly driven to its original place. When installing the cutting product, it is important to ensure that it enters parallel to the holder.

After replacing, it is necessary to expose the knives on an electric plane, adjusting them in height, after which they are clamped with nuts. It is important to consider the same clearance when installing both elements. This is necessary to avoid unbalancing the shaft.

After sharpening the cutting edges, it is important to immediately test the blade by removing a few chips. This is important because the tool blade, which immediately began to be used after sharpening, is dulled much less. To avoid frequent sharpening on the sharpener, it is necessary to monitor the condition of the torch during operation, and when the initial signs appear, it is better to straighten the blade immediately.

Safety when working with a planer

With proper use of the tool, a sufficient amount of work can be performed in a short period of time, but if the precautions are not followed, serious injuries can result.

Before starting work, it is important to secure the workpiece properly, otherwise there is a risk that it can be pulled out during work and it can cause injuries to workers or other people nearby.

During a technical inspection of the cutting elements or when adjusting the knives, the tool should be completely de-energized by disconnecting the electric cord from the power supply, as accidental start-up can cause irreparable harm to health.

Products should be processed by turning on the device in advance and allowing the knives to gain the required speed until the cutting elements come into contact with the wood.

If necessary, put the planer to the side to check the surface being treated, it is important to put it on its side.

During operation, it is necessary to avoid excesses of an electric cord. The integrity of the electrical insulation must be respected. It must be intact, and live parts must be carefully insulated.