Concrete Core Drill Bits: Effective Solution to Repair Issues

Concrete Core Drill Bits: Effective Solution to Repair Issues

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

How to drill holes for concrete sockets on concrete

Recesses in concrete have to be done quite often, including when performing electrical wiring. But places for switches and sockets are prepared in a different way.

To determine the center, you first need to draw cross markings on the wall using a tape measure and a pencil. Then you need to outline the proposed 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 concrete cutter, that is, a crown.

It is a segment of a 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 rotational mechanism. There is a hole in the shank for attaching a center drill that provides the desired direction of rotation of the crown. The drill always comes with a milling cutter. If it is necessary to make a through hole in thick walls, an extension for a concrete crown is used. It greatly 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 depressions themselves turn out uneven.

The main varieties of concrete core drill bits for concrete sockets

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

  • with cutting elements made of hard metal alloys;
  • from tungsten carbide alloys (winning);
  • with diamond spraying.

The method of operation of the hammer drill also depends on the characteristics of the cutting part. For diamond and carbide-tungsten crowns, the shockless drilling method is suitable, for metal, in which the cutting part has the shape of teeth, – shock.

The metal crown can only be used for concrete without reinforcement. The shock effect significantly reduces the service life: such crowns cannot be restored. Use them more often for domestic needs, if necessary, make a small number of holes.

varieties of concrete core drill bits
The crown is a prefab or a single design

Tungsten carbide crowns are also suitable only for unreinforced concrete. They are quite convenient to use when making holes in walls with a tiled surface.

Diamond coated core bits are the most common option. They have a continuous ring coating along the edge. They can make holes in reinforced concrete without using the shock method, which sparingly affects the supports of the structure to be drilled.

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

The principle of operation of diamond core bits for concrete

Diamond core bits can vary in diameter, method of connection with the shank, 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 self-clean from dust arising during work, which makes the drilling process more efficient.

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

For standard grades of concrete, crowns marked “C” are used, indicating that spraying has medium hardness. Coating “T” (solid) is used when operating devices at reduced speeds.

Diamond core bits for drilling concrete can work both with a dry and with a wet method of drilling. Nozzles designed for drilling without water supply have holes in the cylinder body of a special shape that contribute to the cooling of the edge during operation.

Diamond core bit easily pass fittings. The concrete layer during drilling collapses only under the edge; upon completion of work, a stone cylinder remains in the crown.

Diamond crowns for concrete
Diamond core bit for concrete are equipped with soldered wide cutting segments with diamond abrasive.

When making holes of considerable diameter and depth, the drilling machine can be fixed with anchors. This position contributes to more accurate drilling, does not create much dust, prevents jamming of the cylinder and reduces noise. Holes for socket boxes are often performed manually.

Standard core drill bits diameters for concrete

Holes and recesses in concrete both for domestic and industrial purposes may be needed not only for embedding sockets, but also when laying pipes, cables, etc. Therefore, the sampling parameters will be different, which means that you will need tools with holes various dimensional indicators: with a specific diameter for the sockets, for pipes – depending on the cross-section, for cables – in accordance with the dimensions of the route.

Each product is accompanied by instructions, which necessarily indicate the characteristics of the crown, or this information is indicated on the marking.

core dril bits heads have
Core bit heads have a wide range of diameters and lengths.

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

Varieties and cost of concrete core drill bits 68 mm

Sizes of boxes for installing sockets and switches are standard. The recesses for them are carried out using crowns on concrete 68 mm. This is the most common option.

For carbide (winning) options, the cutters are set at a negative angle of 7 °. This arrangement dampens the intensity of the dynamic load on the nozzle, reduces the effect of radial and end runout. You can use such a nozzle for perforators with a power of 850 W or more. The SDS Plus system is used as a mount.

68 mm concrete core drill bits
68 mm concrete crowns are considered the most common option.

The diamond core bit with a diameter of 68 mm most often has 4 segments with a dusting. These fragments are performed by mixing diamond chips and metal powder. The composition is pressed, resulting in the formation of elements of the desired shape and size, which are then baked. The power of the hammer for using this type of nozzle must be at least 600 W, 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 medium grain and are recommended for brickwork, cladding and tile, foam concrete, and hard gypsum. The optimal speed when working with such nozzles is 1500 rpm.

The price of a diamond core drill bit for of 68 concrete mm averages 100-144$. In victorious (with tungsten carbide spraying) species, it is much lower – 58-86$. The cost of metal products is 6-9$.

perforator must have
The rotary hammer must have a power of at least 600 W for using nozzles with a diameter of 68 mm

Scope and methods of using diamonds cores of 72 mm for concrete

A diamond core drill bit with a diameter of 72 mm is also a fairly often used nozzle. It is used when making recesses for sockets, junction boxes or when laying communication pipes. Used with a drill or punch. Crowns of this diameter are divided into two types:

  • for dry drilling;
  • for wet drilling.

The nozzles recommended for dry operation have opposite cutouts on the sides of the cylinder, which provide cooling of the cutting edge during operation. Variants without openings in a cylindrical housing require running water to cool.

Diamond core bit of 72 mm for concrete are used when working in shockless mode. With their help, you can drill concrete, reinforced concrete, natural and artificial stone, ceramics. The recommended power of the rotary device is 700 W and higher, the rotation speed is 1500-2000 rpm. The cutting fragments of the cutters are laser welded, which further enhances the strength of the nozzle

diameter of 72 mm, concrete, natural
Using crowns with a diameter of 72 mm, concrete, natural and artificial stone, ceramics can be drilled.

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

Features of the use of core drill bit of 100mm for concrete

During construction or repair work, it is often necessary to drill large holes, especially for connecting water supply and sewage. In such cases, a crown with a diameter of 100 mm is used. You can purchase such a hard metal milling cutter. It is inexpensive – 5.76-6.48$. You should not be afraid when buying such a mill made in China, its performance is not inferior to Russian counterparts.

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Like a crown for concrete, you need to give time to cool, apply the shock function of power tools. A distinctive quality of this type of cutter is its rather quick wear. If the cutting edge hits the reinforcement, it is significantly damaged, so its further use is called into question. Before starting work, you need to be sure that no metal elements meet on the drilling path.

100 mm diameter concrete core drill bits
A 100 mm diameter crown is used to drill large holes.

More durable in operation when making holes, diamond crowns for drilling concrete, especially for drilling large holes. If the amount of work to be significant, you should purchase the latter option. Even at a significantly higher price (compared to metal crowns), such a mill can be more cost-effective.

Concrete core drill bit 110 mm: application and specifics of fastening

The diameter of metal crowns does not exceed 100 mm, so for drilling holes of 110 mm and 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 hammer with a power of at least 100 watts.

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

Core with a diameter of 110 mm
Crowns with a diameter of 110 mm are fastened with 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 options for large diameters (150 mm or more), some models require a special size of the connecting elements. There are two types of cartridges, which play a major role in the method of attachment:

  1. SDS-plus. They are part of the design of low-power tools, the weight of which does not exceed 5 kg.
  2. SDS-max. They are equipped with heavier and more powerful models of rotary hammers.

The nozzle must have an appropriate shank to match the type of attachment.

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

Important! It is impossible to purchase and install a crown on concrete 110 mm for a rotary hammer with a power of 800 W or less. Using an adapter makes it possible to connect the structure, but this 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.

Concrete mortar crowns: manufacturers overview

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

Crowns for perforators of the domestic producer “Diam Diamond” are also in demand. The company makes nozzles of three types:

  • G. series. High speed and good performance for concrete grades M100-M300;
  • S. series. Recommended for concrete M400-M600;
  • TOP series. Used when working with heavy material.
deWalt oncrete core drill bits
DeWalt crowns are available in all existing standard sizes.

The crowns made by the Bosh company gained popularity and trust among consumers. They confirm excellent German quality. Especially in demand nozzles with a diameter of 68 mm.

The DeWalt line of crowns (an American manufacturer) is represented by models of all existing standard sizes. They can drill to a depth of 80 mm. Concrete crown prices for DeWalt can be attributed to the middle segment. For example, the wear-resistant popular version of the 68 mm nozzle with diamond spraying will cost an average of 100$.

Enkor domestic milling machines are quite competitive. Particularly noteworthy is the 48280 model. This is a diamond crown that can be used when working with concrete of all kinds, including reinforced concrete, as well as drilling stone and ceramics. It is recommended to work with it in shock-free mode. The cylinder has openings for cooling.

Balance of price and quality: core bit for concrete “Distar”

Almost every buyer wants to purchase quality goods at the most reasonable price. Distar diamond coated products comply with these requirements. For 25 years, the company has been supplying the market with tools that are successfully used both in everyday life and for production purposes.

distar concrete core drill bits
You can use the “Distar” core bit as nozzles for different types of power tools

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

Core bit “Distar”, 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 nozzles for different types of power tools with a torque: hand drills, rotary hammers, as well as stationary drilling rigs.

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

You can always choose the product option of this manufacturer with the necessary shank, comparable with the design features of the used electrical equipment. For the fastener for concrete crowns SDS Max, SDS Plus manufactured by Distar, it is possible to match the drill or perforator using a 1 1 UNC adapter and other types of adapters.

Useful advice! When choosing an adapter, you must carefully read the information that makes up the product label. 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 help to avoid problems and ensure the full functioning of the nozzle.

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Resource of diamond core bit for concrete for sockets

The resource of the crown 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 for concrete with a diameter of 200 mm, having saturated diamond spraying, is designed for 18-20 linear meters of drilling in reinforced concrete.

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

Nominal life
Nominal life, confirmed only in case of correct operation of the crown

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

  1. The use of the shock mode of operation of the power tool for crowns with diamond coating significantly reduces the service life.
  2. Rigid fastening of the support stand leads to a distortion of the crown, provokes beating, which adversely affects the condition of the cutting elements.
  3. Excessive pressure and uneven feeding can result in rapid damage to the spray coating.
  4. Drilling without water contributes to overheating and falling off of the cutting layer of the crown.
  5. As a result of the use of nozzles not intended for drilling concrete with reinforcement, metal can not only destroy the coating of the cutting segments, but also lead to a violation of the integrity of the crown.

Important! It is possible to renew diamond spraying 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 the foregoing, we can conclude that the nominal resource determined by the manufacturer will be confirmed only under the conditions of proper operation of the tool.

Concrete core drill bits: how to choose a nozzle

Even with complete information about the nozzle being purchased, choosing the right tool is not so simple. Quite legitimate questions arise. Maybe it’s wiser to take a device with a resource margin? Is it worth it to overpay for a diamond option? To align 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 what material will be processed. If you need a crown on brick, a carbide product is enough. Drilling a large amount of concrete is more reliable with a diamond core drill bits. If reinforcement is theoretically acceptable 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 cartridge height. For through holes, a nozzle may be required. If you plan to drill holes of different sizes, it is better to purchase a set of core bits.

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 core bit. The larger the nozzle diameter, the lower the speed should be. For diamond core bits for concrete, 68 mm is 900-1300 rpm, for nozzles with a diameter of 230 mm – 390-450 rpm. These figures reflect the number of revolutions without load.

choice of concrete core drill bits
The choice of core drill bit is based on a preliminary determination of the hardness of concrete, the drilling method (dry or wet), hole diameters

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

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

You need to understand that a tool, when 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 competently. Only then will he become an assistant to man in his creative affairs.


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