Concrete crown: effective solution of repair issues

Concrete crown: effective solution of repair issues

Recently, not only everyday life has become more comfortable, but also such a troublesome process as repairs, which is compared to a flood or fire. Probably, the crumbs and concrete dust that fill the room while making holes in the walls really have something in common with a natural disaster. All this is in the recent past. Modern tools, including a concrete crown, have made the drilling process much more technologically advanced.

Crowns speed up and simplify the installation of the undercutter, ensuring accuracy and accuracy of work

How and how to drill holes for sub-sockets on concrete

It is necessary to make depressions in concrete quite often, including when performing electrical wiring. Furrows are made with the help of stroborezov. But the places for switches and sockets are prepared in a different way.

Concrete crown — a piece of metal pipe made of tool steel

To determine the center, you first need to put a cross-shaped marking on the wall using a tape measure and pencil. Then you need to outline the intended circle, make four holes with a drill at the intersection of the circle and straight marking lines, as well as in the center. After that, you will need a special milling cutter for concrete, that is, a crown.

It is a piece of metal pipe, one end of which has teeth made of high-strength material, and on the second there is a flange with which the device is fixed to the rotary mechanism. There is a hole in the shank for fixing the centering drill, which provides the desired direction of rotation of the crown. The drill always comes complete with a milling cutter. If it is necessary to make a through hole in thick walls, an extension cord is used for crowns on concrete. It significantly expands the operational capabilities of the device.

The appearance of crowns greatly simplified the process of making holes. When performing work with a drill followed by knocking out concrete with a chisel, not only a lot of physical effort and time is spent, but the recesses themselves are uneven.

The crown allows you to create technological holes of large and small diameter

The main types of concrete crowns for sockets

The cylindrical element of all crowns is the same, but depending on the material from which the cutting part is made, there are several types of crowns for sockets on concrete: 

• with cutting elements made of hard metal alloys;
• made of carbide-tungsten alloys (pobeditovye);
• with diamond coating.

The method of operation of the perforator also depends on the features of the cutting part. For diamond and carbide-tungsten crowns, the shockless drilling method is suitable, for metal ones, in which the cutting part has the shape of teeth, the impact method is suitable.

The metal crown can only be used for concrete without reinforcement. The impact effect significantly reduces the service life: such crowns cannot be restored. They are used more often for household needs, if necessary, to make a small number of holes.

The crown can be a team or a single design

Carbide-tungsten crowns are also suitable only for non-reinforced concrete. They are quite convenient to use when making holes in walls with a tiled surface.

Diamond-coated crowns are the most common option. They have a solid annular coating along the edge. They can make holes in reinforced concrete and without the use of a shock method, which has a sparing effect on the supports of the structure to be drilled.

Useful advice! When buying, it should be borne in mind that using a diamond crown is most often necessary with the use of running water. It cools the cutting edge from overheating, while simultaneously removing sludge and dust generated during drilling

The principle of functioning of diamond crowns on concrete

Diamond crowns can vary in diameter, the way they are connected to the shank, the size, quality and shape of the cutting segments. Products marked “M”, that is, with a soft cutting coating, are used to work with hard concrete surfaces. They are self-cleaning from dust that occurs during operation, which makes the drilling process more efficient.

Diamond crowns are used for drilling reinforced concrete by a non-impact method, which protects the load-bearing elements of structures

Depending on the size of the cylinder, the diamond crown can have 5 cutting elements with a diameter of 6.5 cm or 32 cutting segments – for a device with a caliber of 65 cm.

For standard grades of concrete, crowns with a “C” marking are used, indicating that the deposition has an average stiffness. The “T” coating (solid) is used when the devices are operating at reduced speeds.

Diamond crowns for drilling concrete can work both with dry and wet drilling methods. Nozzles designed for drilling without water supply have holes in the cylinder body of a special shape that help cool the edge during operation.

Diamond crowns easily pass the reinforcement. The concrete layer during drilling is destroyed only under the edge, at the end of the work, a cylinder of stone remains in the crown.

Diamond crowns on concrete are equipped with soldered wide cutting segments with diamond abrasive

When making holes of significant diameter and depth, the drilling machine can be fixed with anchors. This position contributes to more accurate drilling, does not create a lot of dust, prevents cylinder jamming and reduces noise. The holes for the sub-sockets are more often performed manually.

Standard diameters of concrete crowns

Holes and recesses in concrete, both for domestic and industrial purposes, may be needed not only for embedding sockets, but also for laying pipes, cables, etc. Therefore, the sample parameters will be different, which means that tools with different dimensional parameters will be needed to make holes: with a certain diameter for sub-sockets, for pipes – depending on the cross–section, for cables – according to the size of the route.

Instructions are attached to each product, where the characteristics of the crown are necessarily indicated, or this information is indicated on the label.

Crown heads have a wide range of diameters and lengths

Useful advice! If the diameter of the sub-sockets is unknown, measurements should be made with a caliper along the outer edge of the product and, in accordance with the obtained indicator, purchase a crown.

Concrete crowns for the perforator can be sold either separately or as a set. The acquisition of a set is advisable if the application is not episodic. Kits, as a rule, contain 5-10 crowns of various diameters, which will allow, if necessary, to make a hole of any standard size. Rigid packaging and compact placement of tools in it do not cause problems during storage and help protect products from damage associated with external environmental influences.

Varieties and cost of crowns for concrete 68 mm

The dimensions of the boxes for the installation of sockets and switches are standard. The recesses for them are made using crowns on 68 mm concrete. This is the most common option.

In the carbide (pobeditovy) variants, the incisors are installed at a negative angle of 7 °. This arrangement dampens the intensity of the dynamic load on the nozzle, reduces the impact of radial and end runout. You can use such a nozzle for punchers with a power of 850 watts or more. The SDS Plus system is used as a mount.

Crowns on concrete 68 mm are considered the most common option

A diamond crown with a diameter of 68 mm most often has 4 segments with a coating. These fragments are made by mixing diamond chips and metal powder. The composition is pressed, as a result of which elements of the desired shape and size are formed, which are then baked. The power of the punch for using this type of nozzle should be at least 600 watts, the recommended number of revolutions is 1000-3500 rpm, the type of nozzle is SDS Plus.

The most commonly used tungsten carbide coated crowns have an average grain, are recommended for work on brick, facing and tile tiles, foam concrete, solid gypsum. The optimal number of revolutions when working with such nozzles is 1500 rpm.

The price of a diamond crown on 68 mm concrete averages 7-10 thousand rubles. In the pobeditovyh (with tungsten carbide spraying) species, it is much lower – 4-6 thousand rubles. The cost of metal products is 450-600 rubles.

The punch must have a power of at least 600 watts, for the use of nozzles with a diameter of 68 mm

Scope and methods of application of diamond crowns on concrete 72 mm

A diamond crown with a diameter of 72 mm is also a fairly commonly used nozzle. It is used when making recesses for sub-cabinets, junction boxes or when laying communication pipes. It is used with a drill or a hammer drill. Crowns of this diameter are divided into two types:

• for dry drilling;
• for wet drilling.

The nozzles recommended for dry operation have oppositely placed cutouts on the sides of the cylinder, which provide cooling of the cutting edge during operation. Variants without holes in the cylindrical housing require the use of running water for cooling.

Diamond crowns on concrete 72 mm are used when working in shock-free mode. They can be used to drill concrete, reinforced concrete, natural and artificial stone, ceramics. The recommended power of the rotary device is 700 watts and above, the rotation speed is 1500-2000 rpm. The cutting fragments of the cutters are welded with a laser, which further enhances the strength of the nozzle.

With the help of crowns with a diameter of 72 mm, it is possible to drill concrete, natural and artificial stone, ceramics

Useful advice! If the rotation speed of the power tool has slowed down significantly during operation, do not increase the pressure force on the crown. This will not increase efficiency, but will contribute to the wear of the cutting edge.

Features of application of crowns on concrete 100 mm

During construction or repair work, it is quite often necessary to drill large holes, especially for connecting water supply and sewerage. In such cases, a crown with a diameter of 100 mm is used. You can buy such a cutter made of solid metal. It is inexpensive – 400-450 rubles. You should not be afraid when buying such a Chinese-made milling cutter, it is not inferior to its Russian counterparts in terms of performance.

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Such a crown for concrete should be given time to cool, apply the impact function of power tools. The distinctive quality of this type of milling cutter is its rather rapid wear. When it hits the rebar, the cutting edge is significantly damaged, so its further use is called into question. Before starting work, you need to be sure that there will be no metal elements on the drilling path.

To drill large holes, a crown with a diameter of 100 mm is used

Diamond crowns for drilling concrete are more durable in operation when making holes, especially for drilling large holes. If the amount of work is significant, it is worth buying the latter option. Even at a significantly high price (compared to metal crowns), such a milling cutter may be more cost-effective.

110 mm concrete crown: application and specifics of fastening

The diameter of the metal crowns does not exceed 100 mm, so for drilling holes of 110 mm or more, you need to purchase a diamond-coated milling cutter.

To work with a nozzle of this size, you will need an electric drill or a puncher with a power of at least 100 watts.

Working on concrete with a crown of 110 mm, it is better to use water cooling. It will prevent overheating and falling off of the soldered edge.

Crowns with a diameter of 110 mm are attached using two types of adapters

Some difficulties may arise in the process of attaching the nozzle to the power tool. The main part of the crowns is compatible with perforators and drills. As for the variants of large diameters (150 mm or more), some models require a special size of connecting elements. There are two types of cartridges, which play a major role in the method of attachment:

The nozzle must have an appropriate shank to be combined with the type of attachment.

The industry produces adapters (adapters) that allow you to install a crown of one type on a cartridge of another purpose.

To work with a 110 mm nozzle, you will need a punch with a power of at least 100 watts

Important! It is not allowed to purchase and install a crown on 110 mm concrete for a perforator with a power of 800 watts or less. Using an adapter makes it possible to connect the structure, but it does not affect the operation of the engine. A large crown on a low-power power tool contributes to the inevitable overheating with the ensuing consequences.

Crowns for podrozetnik on concrete: overview of manufacturers

There is a fairly large selection of crowns on the market. Among those who have confirmed high quality and good performance are Super Hard. This is an American company with a representative office in various regions. Nozzles with a diameter of up to 80 mm provide drilling using materials of various quality, including reinforced concrete.

Crowns for perforators of the domestic manufacturer “Diam Almaz” are also in demand. The company manufactures three types of nozzles:

• Series G. High speed and good performance on concrete grades M100-M300;
• Series S. Recommended for concrete M400-M600;
• TOR series. It is used when working with heavy material.

DeWalt crowns are represented by models of all existing standard sizes

Crowns produced by Bosh have gained popularity and trust among consumers. They confirm the excellent German quality. Nozzles with a diameter of 68 mm are especially in demand.

The line of DeWalt crowns (American manufacturer) is represented by models of all existing standard sizes. They can drill to a depth of up to 80 mm. The prices of DeWalt concrete crowns can be attributed to the middle segment. For example, a wear-resistant popular version of the 68 mm nozzle with diamond coating will cost an average of 7000 rubles.

Quite competitive are the cutters of domestic production “Anchor”. The 48280 model is particularly worth highlighting. This is a diamond crown, which can be used when working with concrete of all types, including reinforced, as well as drilling stone and ceramics. It is recommended to work with it in unstressed mode. The cylinder has cooling holes.

Balance of price and quality: crowns on concrete “Distar”

Almost every buyer wants to buy a quality product for the most reasonable price. These requirements are met by products with diamond coating of the Distar trademark. The company has been supplying tools to the market for 25 years, which are successfully used both in everyday life and for production purposes.

You can use “Distar” crowns as attachments for different types of power tools

Diamond crowns on concrete 68, 72, 82 mm are the most popular models. They are distinguished by a significant resource and a good drilling speed. Among this type of nozzles, most of them have cooling holes, so there is no need to connect water. Diamond-coated segments have a specific shape that allows you to remove sludge, thereby cleaning the drill from drilling waste that reduces work efficiency.

Distar crowns, depending on the characteristics of the material to be drilled, are divided into three categories:

• for ceramics and cermets;
• for marble and granite;
• for concrete and reinforced concrete.

Crowns can be used as attachments for different types of power tools with torque: hand drills, perforators, as well as stationary drilling rigs.

Distar products have a universal adapter that provides quick replacement and compatibility with other equipment

It is always possible to choose a variant of the product of this manufacturer with the necessary shank, comparable to the design features of the electrical equipment used. For the fastening element of the SDS Max, SDS Plus concrete crowns produced by Distar, it is possible to achieve compliance with a drill or a puncher by using a 1 ¼ UNC adapter and other types of adapters.

Useful advice! When choosing an adapter, it is necessary to carefully read the information that makes up the product marking. If it is possible to test the adapter directly when buying in a store (you should bring a power tool with you), it is better not to neglect this method of testing. It will avoid problems and ensure the full functioning of the nozzle.

Resource of diamond crowns on concrete for podrozetniki

The crown resource depends on objective and subjective indicators. The first should include the characteristics declared by the manufacturer. They depend on the characteristics of the cutting segments and the quality of the material intended for processing. For example, a crown on concrete with a diameter of 200 mm, having a saturated diamond coating, is designed for 18-20 linear meters of drilling on reinforced concrete.

The diamond crown on concrete 68 mm SDS Plus under optimal conditions can pass 14 linear meters. The larger the diameter of the crown, the more significantly its resource increases. It is provided by the presence of a large number of diamond-coated cutting segments.

Nominal life, will be confirmed only under conditions of proper operation of the crown

The subjective reasons affecting the life of the nozzle include the conditions and method of operation:

Important! It is possible to update the diamond coating on the cutting elements of the nozzle, but it is impossible to restore the shape of the cylinder – such a crown cannot be repaired.

From all of the above, it can be concluded that the nominal resource determined by the manufacturer will be confirmed only under the conditions of proper operation of the tool.

The use of shock mode of operation for diamond-coated crowns significantly reduces the service life

Concrete crown: how to choose the right nozzle

Even if there is complete information about the purchased nozzle, it is not so easy to choose the right tool. There are quite justified and legitimate questions. Maybe it’s wiser to take a device with a resource reserve? Is it worth overpaying for the diamond option? To match the needs and capabilities of the tool, it is worth getting acquainted with the following selection algorithm.

First of all, it is necessary to determine which material will be processed. If you need a brick crown, a carbide product is quite enough. Drilling a large amount of concrete is more reliable with a diamond crown. If it is theoretically permissible to have reinforcement in concrete, the latter option is simply necessary.

It is worth evaluating the size of the planned holes and choosing a crown of a suitable diameter having the desired height of the cartridge. A nozzle may be needed for through holes. If you plan to drill holes of different sizes, it is better to purchase a set of crowns.

It is necessary to compare the power indicators of the drive of the power tool with which the work will be performed with the size of the crown. The larger the diameter of the nozzle, the lower the speed should be. For diamond crowns on concrete 68 mm is 900-1300 rpm, for nozzles with a diameter of 230 mm – 390-450 rpm. These indicators reflect the number of revolutions without load.

The choice of the crown is based on the preliminary determination of the concrete hardness, drilling method (dry or wet), hole diameters

When choosing an adapter, it is necessary to take into account the correspondence of the size of the crown and the technical parameters of the power tool. In each specific case, it is necessary to determine what exactly is most important for solving the tasks:

• drilling speed indicator;
• work resource;
• material, manufacturer, price;
• length and features of the shank;
• the presence or absence as a prerequisite of the need to use water as a cooler, etc.

It should be understood that the tool, if used incorrectly, becomes a weapon that is most likely to harm the one who uses it. The essence of the above article is as follows: the tool must be correctly selected and applied with knowledge. Only then will he become a helper of man in his creative deeds.