Setting The Cutter To The Trimmer

24th July 2020

Types of cutters for metal for a milling machine. Classification, features Principles of classifying cutters for metal for a milling machine, drill, hand router. The main types of cutters for working with metal and their features.

Types of cutters for metal

Any novice craftsman who is faced with the need for metal processing has to look for information about what cutters are. Let’s describe the most common types of cutters for their intended purpose.

Disc cutters are used for the following types of work:

Trimming blanks;
Cutting grooves;
Sampling of metal;
Chamfering, etc.

The cutting elements of such tools can be located both on one and on both sides. Depending on the type of processing (from preliminary to finishing), the size of the cutter and its teeth changes. Solid carbide rotary cutters operate in the toughest conditions with high vibration and an inability to efficiently expel chips from the cutting area.

Among the varieties of such tools are:

Groove;
Slotted;
Detachable;
Intended for processing metal parts from two or three sides.

The names of these tools are determined by their purpose: for example, cut-off cutters are needed for cutting off metal blanks on milling machines, and with the help of slotted ones they cut grooves and slots.

Indexable face mills

These cutters work with flat and stepped surfaces of metal parts. From the name itself, it is clear that the end part of the tool is a working one, respectively, the axis of its rotation is perpendicular to the workpiece plane being machined. Most often, such cutters are quite massive, making it convenient to use replaceable inserts in them. A large number of teeth in the area of contact with a metal part allows achieving high processing speed and smooth operation of the tool.

Cutters of this type can be either straight or helical. The first to process narrow planes, and the second work smoother and therefore have received universal application.

Axial forces arising under certain operating modes of helical cutters are very high. In these cases, double tools are used, the teeth of which are located with different directions of inclination. Thanks to this solution, the axial forces occurring during the cutting process are balanced.

This type also includes maize rasp cutters, with which they cut shoulders and cut grooves.

Cylindrical corn cutter in operation

The edge of such a cutter for metal, used for machining inclined surfaces, as well as corner grooves, has a tapered surface. There are both one-corner and two-corner types of tools, differing in the location of the cutting edge (in two-corner models, they are located on two adjacent conical surfaces, and in one-corner models. On one conical surface). With these cutters, you can make flutes in all kinds of tools.

Dovetail angle cutter

For the formation of grooves with beveled side surfaces, single-angle metal tools of the “dovetail” type and an inverted “dovetail” are used.

Most often, end (or finger) cutters for metal are used to create grooves, contour ledges and grooves, and to process mutually perpendicular planes.

End mills are divided into several varieties according to the following characteristics:

Monolithic or soldered cutting elements;
With tapered or cylindrical shank;
For finishing metal (fine teeth) or coarse (large teeth).

Carbide end mills are used to work with poorly machined metals. Steel, cast iron, etc. Among the end mills, there are also spherical (ball) cutters, which are necessary for processing spherical recesses, radius ones that serve for selecting grooves of various shapes, fungal. Carbide cutters for T- shaped grooves on workpieces made of cast iron, steel, non-ferrous metals. End caps also include engravers or engraving cutters, which are used to process precious metals, copper, brass, and other materials.

From the name it becomes clear that this type of cutting tool is designed to process shaped surfaces. Such cutters are actively used for processing metal parts with a significant ratio of the length of the workpiece to its width, since the shaped surfaces of parts of small length in large industries are often made by pulling. Shaped cutters with a relief corner are the most difficult to sharpen.

By the type of teeth, shaped milling tools for metal are divided into two types:

With pointed teeth;
With recessed teeth.

Machining is performed by the rolling method due to the point touching the workpiece with the tool. Hose cutters are divided into a number of subspecies according to the following parameters:

Solid or prefabricated;
Right or left (direction of turns);
Multi-or single-pass;
With unpolished or ground teeth.

Annular cutters (or core drills)

These tools are used to create holes, and the annular cutters provide a higher cutting speed compared to twist drills about 4 times.

There are cutters for metal not only for CNC machines, but also for drills. Otherwise, they are also called burrs. Their design provides a special pin for clamping in the drill chuck. On sale, rotary cutters can be found only in the form of sets, since working with metal with a drill requires precision and appropriate cutter shapes for a specific task.

For a hand router, cutters are also bought as a set. There are edging tools with and without bearing. The former are used for processing the edges of the part on a hand mill, the latter can be used anywhere on the workpiece, but templates are required for their more accurate work. On the domestic market, as a rule, there are Chinese cutting tools for a hand router, but their quality can be assessed as quite high.

At home, for metal processing, you can use a tool such as a drill bit. However, it can only be used for parts of small thickness. Experts do not recommend inserting it into a hand router. It should only be used in an electric drill.

Principles of classifying cutters by metal

Various types of milling machines are determined by the design and purpose of the tool, as well as by the method of feeding the cutter, among which helical, rotary and rectilinear can be distinguished. The working edges of the cutting tool, each of which, in fact, is a cutter, are made of extra hard steel alloys or materials such as ceramics, diamond, carded wire and others.

A variety of cutters makes it possible to sample material in the most difficult areas, as a result of which the workpiece is given the required shape and it turns into a specific part.

Many types of cutters in one photo

The cutters are classified according to the following parameters:

The location of the teeth (cutters);
Construction (prefabricated, one-piece);
Tooth design;
The direction of the teeth;
Method of fastening cutting elements;
Material of cutting elements.

Types of metal cutters for a milling machine. Classification, features

In order to be able to process steel billets, giving them the desired shape, milling machines are widely used in production. Thanks to metal cutters for milling machines, products are obtained in exact accordance with the engineering project. The types of cutters presented today on the domestic market are very diverse, which allows you to choose the option most suitable for a particular case.

Why you need to put the knife on the trimmer

A trimmer with a knife installed on it is most convenient to use for more comfortable mowing of tall and coarse grass in the country. The line on the lawn mower in such cases does not cope. Thin tears very quickly. Using 2.3mm thick cord or homemade rods with cables causes the vegetation to wrap around 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.

If the weeds are mowed with an electric trimmer without a knife, only a fishing line, even if it is thick with a curly section, will not solve the problem. There is always a risk of overheating the motor and damaging the flexible shaft. And it’s all about the large torque of the electric motor. Grass wrapped around the spindle creates strong resistance to the shaft, which resembles a speedometer cable, which does not withstand and twists.

In order to protect equipment from premature wear, manufacturers have provided for the possibility of installing special knives on trimmers. The design and shape of the existing cutting elements allows you to easily cope not only with coarse and overgrown grass, but also to successfully deal with young shrub growth.

How to put the knife on the trimmer

With the arrival of summer, many owners of personal plots are worried about the question of how to put the knife on the trimmer. No less relevant are the questions of why and when it is advisable to replace the line on the lawn mower with a more durable cutting element. In our article we will try to disassemble all this and give useful recommendations to summer residents.

What knives to put on an electric and lawn mower

Before buying and putting a knife on a lawn mower, find out what they are and in what cases they are used. Today manufacturers offer the consumer 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;
According to the shape of its cutting blades.

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

Lawn mowers type;
Mowing areas.

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

Straight bar for petrol trimmer and curved for electric

To put a metal knife on an electric trimmer is not allowed by its design features.

The curved bar of the machine reduces the distance from its working part to the mower’s feet. In the event of a collision of the blades with a stone or other solid object, the scythe is thrown to the feet.
The high torque we mentioned above, in the event of a metal blade hitting a hard object, transfers a large load to the trimmer flex shaft and its motor. What causes them to fail prematurely.
The trimmer handle most often does not have a restrictive bar acting as a stop. That does not exclude injury to the legs.

It is these features that make it possible to use only plastic knives on trimmers with electric motors. Upon collision with an obstacle, the blades are destroyed, thereby protecting the mower’s legs from possible injury.

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

The straight bar design increases leg clearance for complete safety.
Comfortable U-shaped and J-shaped handles provide a firm grip. The D-shaped handles of the lawn mowers are equipped with a limiter that rests on the mower’s leg, which does not allow the head to come close to the feet when the cutting disc meets a solid obstacle.
The clutch of the gasoline engine allows smooth acceleration to the optimum level. And when the blade hits a hard surface, it can absorb part of the impact.

Thus, gasoline trimmers with a metal blade fitted are best used in large areas. They will successfully cope not only with high coarse grass, weeds, burdocks and nettles, but also with shrubs, as well as young trees.

The shape of the disc blades supplied to the trimmer does not in any way 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.

Why you need to put the knife on the trimmer

A trimmer with a knife installed on it is most convenient to use for more comfortable mowing of tall and coarse grass in the country. The line on the lawn mower in such cases does not cope. Thin tears very quickly. Using 2.3mm thick cord or homemade rods with cables causes the vegetation to wrap around 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.

Trimmer. We MAKE THE OPTIMAL CHOICE. Part 3 (trimmer line, trimmer head, trimmer knife)

The optimal choice of trimmer characteristics will not be enough for comfortable cutting of vegetation in the personal plot. Both the electric trimmer and the petrol lawn mower need the right cutting tool. As such, a trimmer line (cord) or a special knife is used.

The type of vegetation is fundamental when choosing what to mow. For the convenience of work, the user can choose the type of cord, the type of trimmer head, the method of threading the cord into it, choose a knife of a certain shape. Therefore, you should familiarize yourself with these characteristics in more detail.

Trimmer HEAD

The trimmer head, often also called the mowing head, is a specially designed reel that contains a cord of a certain length. An 8-15 m piece of cord is wound onto the inner spool, the ends of which are pulled out of the reel to the required length as they wear or break off when they encounter a too hard obstacle.

As a rule, for different models of trimmers, certain mowing heads are used, which differ in both the internal structure and the way of attachment. For some trimmer heads, special adapters are available that allow the use of such heads on trimmers of various models and from different manufacturers.

Trimmer heads are usually subdivided into manual, semi-automatic and automatic according to the type of line feeding. In the first, as the name implies, the line is fed from the head manually. To do this, you will have to stop working, turn off the trimmer and manually lengthen the ends of the cord.

For the second, it is enough to hit the ground with the mowing coil. In this case, by pressing upon impact on a special button, the anchor mechanism is released and the cord is fed due to centrifugal force. Line lengthening is carried out with the trimmer working.

In the third option, to lengthen the cutting line, simply reduce the engine speed, then with a subsequent increase in speed, the trimmer line is automatically fed.

As follows from the above description, the most inconvenient is the mowing reel with manual cord feed, and the most optimal is the mowing head with automatic feed. However, it has not won much love from users due to the increased line consumption compared to other types. Therefore, the most popular and demanded today are semi-automatic trimmer heads.

Also, different models of trimmer heads differ in the way the line is threaded. They can be quick-loading (for example, Shindaiwa Speed-Feed), when there is no need to disassemble the reel to wind a new portion of the cord, and collapsible.

In the first version, you can leave the mowing reel on the trimmer. The end of the cord is threaded through both ears in the spool, then the required amount of line is wound and cut off. Or both ends of a pre-cut piece of cord of the required length are tucked into the corresponding holes and screwed on.

In the second option, to charge a new portion of the cord, the trimmer coil will need to be removed, disassembled and wound on the spool inside. Different models of reels have different ways of disassembling and winding the line. But in all cases, the line must be wound in the direction indicated by the arrow on the body (both ends in one direction).

On cheap Chinese mowing heads, the so-called “no-name”, such an arrow is often absent. Also, branded models may have two arrows in different directions (when it is possible to use them on trimmers with different directions of head rotation). In this case, the cord must be wound in the direction of rotation of the shaft (that is, the engine must wind it). If the cord is wound in the wrong direction, then when the button hits the ground, it will fly out too much.

The opposite option is also possible. When the line does not feed when the semi-automatic mowing head hits the ground. This can be caused both by improper winding of the line, or by the fact that after installation on the trimmer, you simply forgot to pull the ends of the cord out of the retaining grooves on the spool.

Another nuisance when mowing vegetation with a trimmer line is the sintering of the turns inside the coil. This happens because, when meeting with an obstacle that is too hard, the cord is sharply inhibited. With such jerks, it is pulled inward and sticks to the part wound on the spool. As a result, it is necessary to interrupt work, disassemble the coil and tear the stuck together turns of the cord. In some cases, this can be avoided by spraying the line wound on the spool with silicone spray before installing it into the spool.

Most often, a semi-automatic head is used for trimmers, consisting of two spring-loaded parts (body and spool). Structurally, the spool can be in two versions. Two-section, where each end of the cord is wound into its own section, which reduces entanglement and sintering. Or one-piece, when both ends of the line are wound together.

Our craftsmen came up with a simple, cheap and elegant way to turn a one-section spool into a two-section one, the essence of which can be understood from the photographs given.

For this, a ring is cut out of a strong and thin plastic plate, the inner diameter of which corresponds to the thickness of the spool in the winding zone of the fishing line, and the outer diameter to the diameter to the protrusions. That is, such a ring should move freely along the spool. Then a cut is made for the cord, the ring is cut, put on the spool and the cut is glued with tape. Now each end of the line can be wound into the section intended for it.

The prewound mowing head has two or four opposed openings from which the mowing ends protrude. In addition to feeding reels, there are also trimmer heads with plug-in pieces of fixed length line (such as the Oregon Jet-FIT).

In this case, the number of working “mustaches” can reach twelve. Some users consider such a design to be quite convenient, but the other part is unhappy, because they believe that this increases the consumption of the cord and it is necessary to stop working to replace it. In such heads, as a rule, cross-cut fishing line is used.

Trimmer LINE (CORD)

The classic cutting tool for all types of tools is a special trimmer line or line, also sometimes called a string. Its thickness (diameter) ranges from 1.2 to 4 mm. Each trimmer specifies the maximum cord thickness that can be operated without overheating the engine and accelerating bushing wear.

In addition to differences in thickness, the trim cord also has a different cross-sectional shape: a circle, a polygon (from three to hexagon), an asterisk, rounded protrusions, etc. In addition, it can be twisted along the longitudinal axis in the form of a twisted square or a spiral round string, and have various notches and recesses. All these tricks are designed to increase efficiency when mowing vegetation.

The most versatile is the round cross-section trimmer line, which can be used for cutting both fresh grass and dead wood. In addition to this versatile cord, manufacturers also produce more specialized line.

Taking into account that the smaller the contact area of the cord with the stem, the greater the force of its impact, a figured cord with a cross-section in the form of a polygon or an asterisk with sharp corners appeared. Later, for strength, particles of aluminum began to be added to it.

Square fishing line with a thickness of 2.4 mm and more will allow you to easily cope with thickets of dry weeds and even stems of raspberry bushes. The star, on the other hand, is designed for gentle mowing of fresh grass. Due to the profile, it cuts vegetation cleaner, the grass leaves faster after cutting and does not dry out as often as after using a round fishing line.

A round spiral line is considered low noise, but this parameter is only relevant for electric trimmers, since the sound of a running gasoline engine blocks the whistle from any line.

When using a trimmer line with a curly section, its thickness should be taken less than the maximum for this trimmer. This will avoid problems with the supply of line from the mowing head. Fill such a cord into the spool with gloves.

The trimmer line comes in a variety of colors and in most cases it has no functional value. But with some manufacturers, the color determines the diameter of the cord (for example, Stihl) or the properties of the material used (for example, Oregon).

Trimmer lines are made from nylon (polyamide) or polypropylene. Leading manufacturers use PP6 polypropylene for cord production. Various low-quality polyethylene is often added to the fishing line of Chinese origin to reduce the cost. But in any case, after long-term storage, the polypropylene cord becomes brittle. To increase elasticity, such a fishing line should be soaked in water for half an hour before use.

Under no circumstances should thin wire or stranded wire be used as a trim cord. Thinking in this case about the strength and durability of the fishing line, they forget that the trimmer string is specially made in such a way as to break off to soften the dynamic impact on the transmission and engine of the tool. In addition, the cable and wire still break off. At the same time, broken-off pieces accelerated to high speed easily pierce leather shoes.

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