Types of drills - how not to get lost in the variety of tools. Which step drills for metal are better to choose? What are the types of drills for metal?

Metal drills are two-pronged cutting devices that are used to create holes in various materials, including metal structures. Manufactured from alloy steel and hard alloy. They have a wedge-shaped body, which is limited by the anterior and posterior surfaces. The operational parameters of this cutting tool depend on the quality of the manufacturing material, its heat treatment, and also necessarily on the sharpening angle of the cutting part. There are different types of metal drills, each of which performs its own separate function and is used for cutting a specific element.

Classification of drills for metal

There are, for example, twist drills, feather drills, centering drills, for deep annular drilling and with straight flutes. According to several classifications, cutting devices are classified according to different parameters. Let's look at the main ones.

The following types of drills exist:

1. Spiral - the front surface is the helical surface of the groove.
2. Centering - have a combined design, made for centering holes of 60 and 75 degrees with and without a safety cone.
3. Stepped - used for processing holes with a cylindrical countersink specifically for screws that have a cylindrical head, as well as for processing holes and simultaneously forming a chamfer for the next thread.
4. For deep drilling – two screw channels have an elongated screw design.

By type of material there are:

• Carbide alloys;
• High speed steel;
• Universal

In the direction of drilling consider:

• Left;
• Right

Shank types:

1. Cylindrical device (used for processing structural materials).
2. Conical, with Morse taper (used for machining holes without preliminary centering).

By accuracy class:

• Increased accuracy;
• Normal accuracy

Drilling methods, the type and shape of the working part of the cutting tool, the method of manufacturing the tool, as well as its coating also differ.

According to the manufacturing method, they are distinguished:

1. Solid (diameter up to 8 mm);
2. Welded (diameter greater than 8 mm);
3. With replaceable plates;
4. With replaceable heads

By coverage from:

• black oxide film;
• titanium nitride;
• hard alloy;
• low alloy steel;
• titanium carbonitride

There are also several types of drill sharpening:

1. Single-plane;
2. Two-plane;
3. Conical;
4. Cylindrical;
5. Screw

Features of using drills

The most common are spiral devices. They have a diameter from 0.1 to 80 mm. Their design involves the presence of a working part, a shank, which is used to secure the tool in the spindle of the machine, as well as a foot, which serves as the main stop when removing the structure from the spindle or chuck. The base is a cylindrical rod that has two spiral or helical grooves that serve to remove chips while drilling a hole.

photo: spiral drills for metal

Feather drills are used quite rarely; their device consists of a round rod, the end of which is equipped with a flat blade, which has two cutting edges located at an angle of 120 degrees.

Deep-drilling cutting tools are used for drilling blind and through holes in long structures, shafts and spindles. They have low productivity, drilling precise, straight and clean holes. These include gun, single-edged and double-edged with internal chip removal.

Gun blades are used for cutting small-diameter devices, single-edge and double-edge blades are used for cutting medium- and large-sized devices.

photo: gun drill for metal

Ring drilling devices are used for cutting structures with a diameter of over 100 mm. Special cutters and keys are inserted into their body.

Centering cutting tools are designed for processing center holes in various workpieces. They can be manufactured with or without the safety cone and have a combined shape.

photo: center drill for metal

Types of metal drills that have carbide plastics at the ends have greater durability and are also highly productive because they have a high cutting speed. Their body is made of alloy tool steel, the plates are soldered using brass solder to the cutting part of the structure.

Drills with a soldered shank are also manufactured for processing holes that have a small diameter. They have increased rigidity and durability.

Cutting tools with straight flutes are used for machining cast iron installations and materials that are characterized by increased brittleness.

Helical grooves, in turn, are used for processing viscous materials.

Stepped structures are used for processing sheet material; they are distinguished by strength, microhardness, manufacturing accuracy and increased sharpness due to the manufacturing method using turning from whole metal.

Features of drill selection depending on the material of the workpiece

When choosing a cutting tool, you must pay attention to the material from which the workpiece is made. In order to choose the right device, be sure to take into account the hardness indicator.

Designs with plates made of hard alloy VK8 are used for drilling materials made of cast iron, and those made of plastic alloy T15K6 and VK3-M for hardened steels. Carbide structures - for cutting high-strength and heat-resistant steels, processing cast iron and titanium alloys.

In order to cut a hole in the required structure, structures made of high-speed steel R18 and R6M5 are used. They have high cutting speed. Tungsten steel P18 is intended for the manufacture of shaped and complex tools that must have high wear resistance. R6M5 is used for steel and cast iron at increased cutting conditions.

What is a drill? How would you answer this question? For many, this is an ordinary metal rod with wavy grooves connecting to each other at its very top, designed to... The definition is partly true if we are talking about the most common type of drill. But what if we need a drill for a specific job, and we want it to meet the requirements that we place on it? And not only for its purpose, but also, of course, for its wear-resistant characteristics, that is, so that it does not bend, break or become dull. How to choose a drill among the huge variety of drills in terms of caliber and color? This will be discussed in the article.

Much depends on what we will be dealing with during drilling work. It could be metal, concrete, wood or even a more fragile material - glass. But first things first.

Metal

Metal drills are especially often used in domestic conditions. Such a drill must be made of quick-cut steel, the marking of which always contains the letter “P”: P6M5. A drill made from P18 steel is considered one of the most durable in this line, however, you are unlikely to find such a drill. Perhaps this is explained by the fact that today the market is dominated by tools made mostly in China, which are not of good quality. Therefore, today craftsmen for their professional activities try to purchase drills dating back to the times of the USSR. They are the most popular due to the quality of the steel, but this is already a big shortage.

If you have to make holes in cast iron or steel, then visually such a drill should be “blunt” at the end: the angle is 116–118º. For very hard alloys: 130–140º. Well, if you have to drill into softer metal (soft aluminum, copper, etc.), then the angle should, on the contrary, be more acute: 80–90º.

Concrete

• If this hole is about 12 mm, then a feather one will do just fine. Glaziers also call it a glass pen because of its corresponding shape in the form of an arrow or a spear.
• If you need to drill a hole larger than 12 mm, then a crown (tubular drill) will fit. In appearance, this tool resembles a concrete crown, with the only difference being that this crown contains diamond coating rather than carbide brazing.

Pay attention to color

You may have noticed that drills come in different colors. What does it matter? The color itself indicates whether the instrument has undergone any processing. If it has a steel color, then this should tell you that there was no processing. The black drill indicates that this tool is highly durable and has been treated with superheated steam. Heat treatment in salt baths or in furnaces with forced air circulation will give the drill a golden-matte hue, or, if the tool has a golden-glossy color, this indicates that titanium nitride is applied to its surface as a hardening layer. It is worth saying that such a drill is stronger and more durable.

When purchasing a drill, pay attention to the cutting edges. They should have a uniform color and be well sharpened along the entire length. The tool itself should not have any chips, cracks or burrs on its surface.

So, we figured out which drill to use to drill this or that material. But, perhaps, the most important thing is that you most likely already know what this drill should be, not only for its purpose, but also for its quality. We hope that the tips in this short article helped you with this.

For those who carry out construction and installation work, the drill will be the best assistant. When inserted into a drill or other power tools, it will drill a neat hole or tighten a screw.

There is no universal drill, and an incorrectly selected one will ruin the job or make it impossible, so you should carefully choose it. In most cases, you will have to select a drill yourself, because, unfortunately, not every seller in a hardware store will give the right recommendations on the quality of this tool and the work for which it is suitable.

Do I need to buy drill bits in sets? How do you know what shape a drill should be? What drills are suitable for? You will find answers to questions in the article.

1. Spiral – universal, suitable for any type of hole;
2. Conical - characterized by a smooth conical shape, suitable for holes of any diameter. Need constant supervision from a master;
3. Stepped – also conical in shape, but they make the process of drilling holes of a certain diameter easier due to the presence of steps of different sizes;
4. Core cutters (annular cutters) – for holes with a diameter of 12 to 150 mm, multi-layer materials. They are characterized by low cutting force and produce high roughness values ​​that cannot be achieved with other types of drills. Suitable even for conventional drills. The shank must be strong and powerful to prevent slippage in the chuck. They are chosen depending on what kind of work is being done and what type of steel is being used. They differ from wood drills by the sharpening angle and the presence of two longitudinal grooves that divert the chips to the side.

Options in the photo

The most powerful drills for large holes
Due to the steps of a given diameter, such drills make it easier to drill standard holes. Working with a conical drill requires constant attention from the master. Twist drills are the most familiar and common

Professionals identify 5 points of general criteria for choosing a metal drill:

1. The type and characteristics of the metal you are going to work with, including the grade of steel;
2. Depth of “penetration”;
3. Type of drilling (through or penetrating);
4. Hole diameter;
5. What tool do you use (hand or electric drill, varieties - hammer drill, screwdriver or drill), its general characteristics.

Please note that you should not buy a set of drills for household use. If you don't use drills for professional purposes, you won't need many tools and your money will be wasted. If you are going to buy a drill for permanent use, do not skimp.

Features of choice

Professionals choose drills based on the following criteria:

1. Material;
2. Blossom;
3. Labeling;
4. Sharpening angle;
5. Size;
6. Shank;
7. To the manufacturer.

It’s not difficult to identify them by eye, but before doing this, be sure to find out what type of drill you have. For example, large cross-section holes will require low-speed, high-power drills with appropriate drill bits. Additionally, please note that some types of drills are used only with cooling solutions, in order to avoid burning them and the metal.

Which material is better

To use a drill at home, it is better to choose one drill for working with metal of different densities. When choosing a tool for working with aluminum and steel, focus on cost.

Cheap - Chinese-made products. They quickly break or become dull. For long-term work, they will be required in the plural, and their total cost is disproportionate to the purchase of a single, but high-quality drill.

When looking for quality tools, turn to products from well-known brands. They are made of solid steel and are solid rolled.

Top quality drills - solid rolled

Counterfeits are determined by weight. The drill should not be too light.

Choose by color

On store shelves you can find drills in the following colors, which directly indicate their quality:

This does not mean that you don’t need to buy gray or black drills. Approach the choice from a practical standpoint - if you only need to drill a couple of holes, you can save money by buying several drills, and if you are planning more global work, it is better to buy a “golden” drill, which will last much longer.

Marking

All data about the drill is printed on its shank

The drill marking implies a certain combination of alphanumeric values ​​and indicates:

• Drill diameter;
• Steel hardness;
• Metal impurities in the alloy;
• Technology and place of production.

Please note that markings are not placed everywhere - for example, drills with a diameter of less than 2 mm do not have them. On domestically produced instruments with a diameter of 2 to 3 mm, a mark and section are given, on products with a size of 3 mm or more - data on the cross-section, grade of metal, impurities in the alloy, brand. If you decide to buy imported drills, they will indicate the country of origin, brand of company and metal alloy, drill diameter and cross-section, accuracy class and recommendations for use.

The highest quality drills are characterized by the USSR marking.

Main types of marking:

• HSS-R and HSS-G – suitable for working with cast, alloyed, carbon steel with a strength of up to 900 N/mm2, aluminum, cupronickel, graphite, bronze or brass alloy and cast iron;
• HSS-G Co 5 – for processing metals with a strength of up to 1110 N/mm2, suitable for drilling stainless steel, carbon, alloy, non-heat-resistant, heat-resistant steel;
• HSS-GTiAN/TiN – drills with titanium-nitride-aluminum coating, suitable for working with cast iron, brass, cupronickel and bronze, cast steel.

There are also drills made of cobalt (one of the most expensive and durable types of drills, suitable for drilling hard metals) and hard metal alloys (suitable for processing thick metals, have a one-sided, sharp sharpening angle).

Sharpening angle

The sharpening angle is the angle between the edges

The sharpening angle is the angle between the edges. It differs for different types of metal. For example:

• Drills for steel have a sharpening angle of 116-140 degrees;
• To work with bronze, brass and aluminum, you will need a sharpening of 110-135 degrees (such drills are most common);
• For “stainless steel” - 120 degrees;
• For cast iron - 118 degrees.

The ease of drilling different types of metal depends on how correctly you select the drill according to the sharpening angle.

What size are drill bits?

There are different sizes of drills, but our country’s GOST sets the following parameters:

• Short (GOST 4010-77) – diameter 0.3-0.20 mm, length – 20-131 mm;
• Extended (GOST 10902-77) – diameter 0.3-0.20 mm, length – 19-205 mm;
• Long (GOST 886-77) – diameter 1-20 mm, length – 56-254 mm.

They allow you to make holes of different depths.

What is a shank and what are they?

The shank is the part of the drill that is clamped by the drill or hammer chuck. At first they were of the same type - tetrahedral, placed in the hole of the drill chuck and secured with a screw. Later, improved types of shanks appeared, used for various types of tools.

Shanks are:

1. Cylindrical - found most often. As a rule, such products have the same base size and drill diameter. Sometimes there are models in which the shank is thicker or thinner than the drill. The disadvantage is that the shank slips, which makes it impossible to transmit a large torque to the drill. Advantage - if the drill jams in the working surface, the drill will be protected from damage;
2. Hexagonal (aka hexagonal and hex) shanks - suitable for various types of drills. Disadvantage: insignificant accuracy when using a ¼-inch holder;

   This shank shape fits almost any drill model

3. SDS shanks are the brainchild of TM Bosh for hot changing drills in rotary hammers. There are different types: SDS (with two grooves with a diameter of 10 mm, inserted into a 40 mm chuck), SDS-plus (common shanks with a diameter of 10 mm, placed into a 40 mm chuck, used on light hammer drills, drill diameter - 4-26 mm ), SDS-top (rare, have 2 open and 2 closed grooves, characterized by a diameter of 14 mm, in a chuck - 70 mm, drill diameter - 16-25 mm, suitable for 4-kg class hammer drills with a replaceable chuck), SDS -max (widespread, suitable for drills over 20 mm, inserted into a 90 mm chuck, diameter 18 mm, have 3 closed and 2 open slots), SDS-quick (4-10 mm), SDS-hex (used in jackhammers, pikes, drills);

   Shanks designed specifically for rotary hammers

4. Splined shanks – have the same parameters as SDSMax;
5. Triangular - clamped into three-jaw chucks, the main advantage is that they transmit large torques;

   

In the process of processing metal, wood or other materials, one of the frequent technological operations is drilling cylindrical holes of various diameters and depths. To obtain a recess in the thickness of the workpiece, a special cutting tool is used - a drill.

The principle of operation of the drill is rotational-translational. In general, a drill consists of a working part and a shank. The scope and effectiveness of this tool depend on the shape, size, geometry of the cutting part, angle and other technical characteristics.

Drills are traditionally made from high-speed, carbide, alloy and carbon tool steel. Among the new products in production are metal-ceramic alloys, characterized by increased strength.

Using a drill, you can not only drill through a part, but also perform blind drilling, with partial penetration into the material, and also drill a finished hole to the required parameters. For each of these tasks, a tool with a suitable geometry is selected.

Correctly navigating the variety of manufactured drills is not an easy task. In order not to make a mistake in choosing and then not “screw up” the part, you need to have an idea of ​​the purpose of this tool, its types and features of application. To help the novice master, we give some useful recommendations.

Pay attention to the color of the material from which the drill is made: it is the first clue about the strength of the tool.

1. The gray color indicates that this is an ordinary drill of medium strength. It is quite suitable for single drilling, but will not cope with a large volume of work.
2. Black - indicates that the steel has been treated with superheated steam, which guarantees a higher quality of the product.
3. A golden hue is a sign that during the manufacturing process of the drill, a procedure was carried out to relieve the internal stress of the steel.
4. The bright gold color indicates a high degree of strength and reliability of the instrument. Surface treatment with a titanium compound significantly reduces the friction of the working part of the drill during operation, which has a positive effect on extending its service life.
5. The cost of drills increases in the same order in which they are listed. Having decided on the preferred color, let's move on to the purpose of the tool.

How to choose drills for different types of materials

Let us immediately note that you can find high-performance drills for universal use . They are suitable for working with almost any material. In their design, the developers combined the advantages of different tools, resulting in a multifunctional tool that can be used for many repair and construction operations.

Universal drills have special sharpening of cutting edges and precise centering. The working part of the tool is made of durable alloy tool steel, and rapid removal of metal dust or sawdust is ensured due to the presence of a deep spiral.

In the opinion of experts, the use of a universal drill makes sense for a large volume of various operations. If there is a short series of drilling holes, for example, in wood, then in this case its functions will be redundant, and energy consumption will be unreasonably high.

• metal;
• tree;
• concrete;
• ceramics and tiles;
• brick;
• plastics;
• glass, etc.

Metal drill

To process holes by cutting metal, various types of drills are used: spiral, centering, flat (feather) and all kinds of special devices. You can drill alloy and non-alloy steel, stainless steel, cast steel, gray cast iron, acid- and heat-resistant steel. It is important to accurately select a drill with sufficient heat resistance for each type.

Twist drills

The most popular are twist drills with a diameter from 0.1 to 80 mm. The working basis of such a drill consists of two parts: cylindrical and cutting. In the cylindrical part there are two helical chip flutes, through which metal dust and shavings are removed during drilling. There are also ribbons that serve to minimize friction of the tool against the walls of the hole.

The cutting part is two sharply sharpened edges located in relation to each other at an obtuse angle: it differs for different materials. For example, steel and cast iron of normal hardness are processed with a drill with an angle of 115-118°. In order to prevent jamming or repeated cutting of chips, a reverse cone is provided in the cutting part of the drill.

To fasten the drill in the tool chuck there is a shank, which can be cylindrical, conical, in the form of a three-, four- or hexagon, as well as the SDS type. To prevent the conical shank from turning idle during operation, it is equipped with a special holding foot.

Center drills

The best cutting tool for quickly creating center holes. These drills are made from high-speed steel, so the products have exceptionally high strength characteristics. Using a centering drill, a master can easily drill a neat hole with a diameter of 0.5 to 10 mm, located strictly perpendicular to the surface being processed.

All drills of this type are divided into 4 groups:

1. Type A – for holes with an angle of 60° without a safety cone.
2. Type B – the same, but with a safety cone and an angle of 120°. Differs from type A in the diameter of the shank.
3. Type C – angle 75° (safety cone is not provided).
4. Type R - the cutting edge is made not with an angle, but with a radius.

Centering drills with a diameter of up to 0.8 mm are made single-sided; everything over 0.8 mm is double-sided.

Feather drills

Feather drills are available for drilling large diameter holes. . They look like a spatula and, unlike spiral or screw ones, have a flat working part.

Drills with carbide inserts

To work with hard-to-cut types of steel, drills with carbide inserts are used. They are designed for drilling heat-resistant steels, cast irons and are often used in hand-held power tools - drills, hammer drills and others. Due to the special shape of the shank, the drill with the insert can work with impact.

For deep drilling

Another type of cutting tool for metalworking is deep drill bits - more than five diameters. Since drilling large holes is an energy-intensive process, and the drill can become very hot during operation, its design included two special screw channels for the internal supply of coolant.

According to the cutting depth, drills are distributed into four series:

• short – up to 5D;
• medium – up to 10D;
• extended – up to 15D;
• long – up to 30D.

There are also more powerful types of drills for cutting deep holes - ejector and cannon , but they are used exclusively in industrial drilling machines and are not found in hand tools.

If you need to drill a hole with a diameter of 0.4-3.6 cm in thin sheet material (for example, in roofing sheet or plastic), an excellent choice would be step type drill . It is convenient in that it can independently, without replacement, make holes of different diameters.

Or a machine designed for drilling holes in various materials. Drills are made from high-quality hard steel, which allows them to be used for working with other metals, concrete or stone.

Kinds

Depending on their purpose, drills are divided into categories according to:

• Metal.
• Tree.
• Stone and brick.
• Glass and tiles.

They differ from each other in shape, as well as sharpening angle and cutting edge. Most of them are highly specialized and cannot be used for other purposes.

For metal

These drill bits are not only suitable for drilling metals, but can also be used for working with plastic and wood. Depending on the form of manufacture, they come in the following varieties:

• Spiral.
• Conical.
• Crowned.
• Stepped.

Spiral

The spiral type is a classic design that is familiar to almost everyone. The tool consists of three parts - the cutting edge, the working surface and the shank. The cutting part has a sharp sharpening; it is this part that cuts into the metal, forming a hole. The working surface is a spiral, the purpose of which is to remove chips from the hole. The tail part is used to fix the tool in the chuck of a drill or machine tool.

This type is usually made from high-speed steel grade HSS, P18 or P6M5. As for P18 steel, it is quite rare and at the moment only some enterprises located in Belarus are engaged in the production of tools from it. It makes very reliable drills that hold an edge well.

Conical

Such a drill can usually be found clamped into a specialized machine. Its working part is a cone, the top of which cuts into the surface of the metal, forming a thin hole. As you move deeper into the material, contact occurs with a wider part of the cone, which causes the hole to widen. Thanks to the use of this design, drilling can be achieved in one pass. For example, if you use a regular twist drill, you first need to make a hole with a thin tool, and then with a thicker one, gradually bringing the diameter to the required parameters. The cone shape allows you to avoid such inconveniences, but unfortunately, it is not suitable for weak drills.

Crowned

The crown structure is a hollow cylinder, at the lower end of which there are sharp serrations resembling a crown. This tool allows you to make large diameter holes, ranging from 30 mm or more. The disadvantage of this design is that it cannot be installed in a conventional drill chuck. The tool can be used for drilling sheet metal up to 10 mm thick. Typically, HSS steel is used to make hole saws. Also on the market you can find drills with carbide tips or diamond coating. They allow you to work not only with metals and alloys, but even with concrete.

Stepped

The stepped design is one of the latest inventions in the world of cutting tools. It has universal application because it allows you to make holes of various diameters. The name of the type is due to the fact that it is a cone with steps. This drill can only be used for working with sheet metal up to 2 mm thick. The principle of operation is that the tip of the tool cuts into the material, and when it breaks through, it contacts the wider part of the cone, which drills the recess even further. Thus, in order to obtain the required diameter, you need to go deeper to the desired step.

On wood

Often when working with wood, a standard twist drill for metal is used. It allows you to make a hole with a diameter from 2 to 18 mm. However, this type greatly limits the possibilities of woodworking, so several special types of drills were developed and introduced:

• Spiral on wood.
• Feathers.
• Screw.
• Hole saws.
• Ballerinas.
• Forstner.

Spiral on wood

Spiral wood drills are very similar to a regular metal drill. The only difference is the shape of the cutting edge. It resembles a trident. A sharp tooth in the center allows for precise fixation at the drilling site. Tool steel cuts into wood easily. The special design allows you to obtain a very high-quality hole, without tearing out fibers, as happens when using a metal tool.

Feathers

The feather has a flat design, at the end of which there is also a trident, as in the previous type. It provides a large drilling diameter, while allowing installation in a conventional drill. This type cuts clean edges without broken wood fibers. It should be noted that if a small recess is drilled, a groove from the main tooth will remain in its center. This drill only works at low speeds. It is often used with a hand crank.

Screw

Screw drills resemble twist drills, but have a more advanced working part for chip removal. They are quite long, so they allow you to make deep holes. They are often used for drilling timber and logs. Often such a drill has a special handle, which allows you to work even without using a drill, machine or brace. The pointed part of the tool resembles a screw; it cuts into the wood, pressing the cutting edge against the grain. The cut is clean and neat, even when working with raw wood.

Hole saws

This tool is a hollow cylinder with saw teeth on the end and a conventional twist drill protruding forward. It allows you to make holes in boards, plywood and lining. It is usually used to obtain wide openings necessary for installing lamps. The tool is suitable not only for wood, but also for polystyrene foam, PVC lining and cellular polycarbonate. Such drill saws can be used to cut into a seat when installing a socket in a wall, of course, provided that it is made of wood or soft blocks - foam concrete, clay, etc. The removal of the central part can be completed using a chisel.

Ballerinas

Ballerina is an adjustable wood drill bit. It allows you to make wide holes in plywood, chipboard, MDF and OSB boards. Its design is a cross, the center of which is made in the form of a spiral drill. Sharp incisors are attached to the shoulders of the cross, cutting through sheet material. A special key allows you to change the distance between the cutters, thereby adjusting the diameter of the resulting hole.

Forstner drill

The tool has a cylindrical shank with two cutting edges. It is used mainly in furniture production. With its help, you can make a large-diameter recess for installing hinges on cabinet doors. As a result of its use, a neat hole with a flat bottom is obtained.

On concrete

Concrete drill bits are also suitable for working with stone and brick. They come in three types:

• Spiral.
• Screw.
• Crowned.

They all have special soldering tips that bite into stone, concrete and brick. Soldering can be made from pobedite plates or be artificial diamond crystals.

Spiral

Spiral ones are installed in . They have an almost identical design to metal drills, with the exception of soldering. They work best with concrete and brick. The depth of the hole usually does not exceed 80-100 mm.

Screw

Screw ones also have soldering. They are longer than spiral. They are used in cases where it is necessary to punch a deep hole. The screws provide efficient dust removal, reducing the chance of getting stuck. However, it is still worth periodically pulling out the hammer drill to check for dust.

Crowned

Their design resembles a standard wood crown. There is a twist drill bit in the center that cuts into the concrete, stone or brick, with the brazed bit doing the bulk of the work of drilling the hole to the required depth. Such drills also require impact drilling, so they are not suitable for a conventional drill.

On glass

For drilling ceramics and glass, only two types of drills are used - crowns and feathers. The crowns are diamond coated. Their diameter ranges from 13 to 80 mm. Diamond coating consists of glued grains of sand from an artificial mineral. To use a crown, you must have a quality drill or drilling machine. It is important that the tool touches smoothly without creating runout or uneven pressure distribution.

A feather drill is a classic metal rod with a sharp spear at the end. The tool is offered in a small range of sizes 3-13 mm. The cutting feather is made from pobedite, and in more rare cases from other alloys.

To work with glass, you need to approach the choice of drilling tools responsibly. Unlike other materials, there is no room for error with it. A cutting part that is not straight enough or sharp enough can lead to a crack in the glass, ceramics or tiles, which will be irreparable.