Marking drills for metal. Which metal drills are better - selection criteria, types, brands and tips for storage and operation Coating of a metal drill

Drilling cast iron, ferrous and non-ferrous metals requires careful selection of equipment and equipment with sufficient power. Drills designed to work with soft materials, will not be able to cope with metals. The work will be slow, the finished holes will be of poor quality, and the drills will be subject to excessive wear and require regular replacement. All these problems can be avoided if you decide which metal drills are better.

Main criteria

Universal drilling tool various materials does not exist, and even seemingly similar metals may have completely different equipment requirements. High-quality drills from reliable manufacturers are quite expensive, but with the right choice they can last for a very long time, saving a lot of time and money on the job.

When choosing a tool, you need to pay attention primarily to the following points:

If you make a choice, focusing on these points each time, the likelihood of receiving low-quality products is minimized.

Selecting a drill type

Main types of drills three: spiral, stepped and conical (countersinks). A fourth type is somewhat less common - annular cutters, also called core drills. They are designed to create large holes up to 150 mm.

To decide on one Of the types among these options, you need to focus on the following selection criteria:

1. Required diameter of the finished hole.
2. Penetration or through drilling is required.
3. Steel grade, appearance products and other features of the processed metal.
4. Required hole depth.
5. Characteristics and features of the tool used for work: drill, screwdriver, hammer drill, etc.

You should not buy drills in whole sets if they are required in isolated cases and for household purposes: such a purchase will be economically unjustified. For domestic purposes, it is advisable to purchase goods individually, for specific needs, and for professional purposes, in sets, depending on the field of activity.

Shank selection

The shank is the part that is attached to the chuck of a drill or other tool. There are three common types of fasteners: conical, cylindrical and hexagonal. Good metal drills can have any type of fastening: this only affects the tool that can work with a specific equipment.

Based on this, for hand tools It is advisable to choose drills with hex shanks. It is important to remember that you cannot replace one type with another, so the final say remains with the equipment used. Compatibility of equipment with equipment guarantees maximum efficiency work.

Alloy composition and markings

The cutting part of the tool will only be able to drill through a workpiece or work surface if it is significantly stronger than it. To make it easier to determine which products are made of what, metal drills are specially marked. In addition, many types of spraying and alloys can be immediately recognized by color.

How metal drills are marked:

Carbon is not indicated in the labeling, since it is always present in the original raw materials. The same is true with chromium, although its content can reach up to 4%. Domestic marking is even simpler: next to each letter denoting the metal there is a number indicating its percentage in the alloy. For example, the designation P7M6K6 indicates 7, 6 and 6% tungsten, molybdenum and cobalt content, respectively. The letter F may also appear - vanadium, but the cobalt version and alloys with molybdenum and tungsten are more common.

Metal drills: dimensions, table (DIN marking data - imported designation for high-strength steel, like HSS).

Color interpretation

All options laid out on store shelves can be divided into four categories based on color. Each color says a lot about the quality of the equipment and its intended characteristics.

The choice should be approached from the point of view of practicality. If the store has inexpensive options black, they will do an excellent job with everyday tasks and one-time jobs. It makes sense to spend money on high-quality products in golden shades if you have to great job and tens to hundreds of holes in the metal.

Popular manufacturers

There are a number of manufacturers whose products you can trust. There are few of them, and most of the companies are quite well known and well-known.

Need for processing various products made of metal occurs not only among professionals, but also among many home craftsmen. When performing such processing, you cannot do without special tools, one of which is a metal drill. On the modern market, you can purchase already complete sets, including products of different diameters and lengths, or opt for a single copy that meets the required geometric parameters and mechanical characteristics. In both cases, the question arises of how to distinguish high-quality drills from low-quality ones and choose a tool that does not have to be changed after each processing cycle due to its breakage or critical dullness of the cutting part.

Drilling metal is labor-intensive and complex process, requiring a responsible approach to the selection of cutting tools

Varieties and design features

There are various types metal drills, differing from each other in design features and functionality. It is important that using drills designed for metal work, you can successfully drill holes in other materials, which include:

1. wood and wood-based materials;
2. various types of polymer materials;
3. ceramics;
4. brick;
5. concrete.

The design of drills for metal work is specially developed to solve certain technological problems and taking into account the characteristics of the material for which they will be used. That is why experts advise those who do not know how to get an idea of design features such a tool.

It is very important not to get confused in the variety of types of metal drills

Drills intended for metal processing consist of the following elements:

• the cutting part, which performs the main work of cutting metal;
• a shank with which the tool is fixed in the chuck of the equipment used;
• working surface responsible for removing chips from the processing zone.

Depending on your design drills for metal processing are divided into several categories:

1. flat;
2. spiral;
3. crowned;
4. conical

Drills whose working part is flat are also called feather drills. Their most significant advantages are:

• insensitivity to distortions that any drill is subject to during processing with its help;
• simplicity of design;
• low price.

If we list the main disadvantages of tools of this type, they include:

• inability to use for drilling large diameter holes;
• lack of automatic removal of chips from the processing zone (the design and geometry of such drills do not imply this option).

Twist drills are the most common tool used to make holes in metal products. By its design, a twist drill is a cylindrical rod, on the side surface of which spiral grooves (one or two) are made, covering the entire working part of the tool. It is precisely such elements of a twist drill, such as helical grooves on its side surface, that ensure the removal of chips from the drilling zone.

Depending on the design and purpose, a twist drill can belong to one of the following categories.

• Cylindrical drills for general metal work. The diameter of drills included in this broad category can reach up to 80 mm. They are actively used both in production and at home.
• Left handed twist drills having very limited area applications. You cannot do without them in cases where it is necessary to drill a bolt with a broken head or a fastener from a threaded hole that cannot be unscrewed in any other way. There is a simple answer to the question of how to distinguish a drill of this type from a standard right-handed one: just look in which direction its spiral groove twists.
• High precision drills. They are chosen by those professionals or home craftsmen who are interested not in a good, but in an excellent result of the upcoming processing. Tools of this type can be recognized by the designation A1. They allow you to create holes whose diameter is maintained to within a fraction of a millimeter.

Drills of this type, made in the form of a metal cup with cutting teeth on the end working part, are used to create large-diameter holes in metal. The cutting teeth of such drills can be made of carbide or coated with diamond.

This category includes tools with a smooth and stepped working surface. Used to make holes in metal products of small thickness, they provide easy centering of the hole at the very beginning of drilling, which cannot be said about a tool with a cylindrical working surface. However, the main advantage of using stepped cone drills is that with the help of one such universal tool you can produce holes of different diameters.

Among metal drills, we should highlight tools that can be used to make holes even in high-strength materials.

These are tools created on a base doped with cobalt. Cobalt gives the drill high strength, as well as resistance to deformation under thermal and mechanical influence. Thanks to these characteristics, cobalt-type tools are successfully used for drilling holes in products made of high-strength and tough metals and alloys. Quite a high cost, which differs cobalt drills, is fully justified by their characteristics.

Carbide inserts are fixed on the cutting part of this type of drill. The main body of the tool is made of. For the production of plates, carbide alloys are used, which are characterized by exceptionally high hardness and wear resistance. By using such drills, the cutting plates of which are sharpened during the manufacturing process and are not subject to further regrinding, it is possible to successfully drill especially hard metals and alloys, as well as metal products of large thickness.

When choosing drills for metal, you must know exactly what technological tasks they will be used to solve, and also take into account the characteristics of the material in which you need to make a hole. To choose a tool that will meet your goals, you must also pay attention to the following parameters:

1. surface color;
2. quality of sharpening and symmetry of structural elements;
3. working diameter;
4. compliance of the form with standard parameters;
5. characteristics of the material of manufacture;
6. purpose and functionality;
7. manufacturer's reputation.

When deciding which drills to choose for metal processing, you should also take into account the characteristics of the equipment with which they will be used.

So, if you need to drill a large diameter hole in a metal product, for which powerful low-speed drills are used, you will need a tool that can be used in conjunction with them.

What does the color of the drill surface indicate?

The color of the surface of a metal drill is a parameter by which one can judge the quality of the presented tool. So, various colors metal drills mean the following.

This color has the surface of drills that are of the lowest quality and, accordingly, the lowest cost. Tools with a surface of this color are not subject to any additional processing that could increase their hardness, resistance to deformation and combustion. It should be borne in mind that when drilling hard metal, they may not be enough even for one hole.

The surface of the drill acquires this color if it is treated with superheated steam. As a result of this treatment, the strength and wear resistance of the tool increase, and, as a result, the resource of its use increases. The cost of such products is slightly higher than gray ones, but is quite affordable for most consumers.

This color means that the drill has undergone a tempering procedure after manufacturing. This heat treatment allows not only to eliminate residual stresses in the internal structure of the tool, but also to improve its strength characteristics. Even in the photo, such a drill looks presentable and immediately inspires confidence in the quality of its workmanship.

This is the color of the best metal drills, the material of which contains titanium. Due to the content of this element in the steel from which drills are made, the level of friction during their use is reduced, which has a positive effect on the duration of their effective operation. Naturally, drills with a bright golden surface are quite expensive.

When choosing drills of a certain type, you should proceed from how often you will need to use them for metal work. It is also necessary to take into account the requirements for the accuracy and quality of the holes that need to be created in the metal product.

For frequent and intensive use in order to make high-quality and precise holes, it is better to choose more expensive, but also the highest quality bright golden drills.

Purchasing a cheaper tool will mean that you will have to change it quite often, and this will negate the initial savings. It is advisable to choose more affordable types of drills, the surface of which is painted black or light golden in color, in cases where you need to perform one-time work related to drilling metal.

Classification by size

Modern manufacturers produce drills for metal work in a wide range of working sizes. To make it easier for the consumer to understand this variety, the corresponding regulatory document (GOST) provides for the division of metal drills into different types by size. Thus, the following categories of instruments are distinguished:

• short series, the length of which is in the range of 20–131 mm, and the diameter is 0.3–20 mm;
• elongated, the diameter of which, like the short ones, is in the range of 0.3–20 mm, and the length is 19–205 mm;
• long series, the length of which can be in the range of 56–254 mm, and the diameter – 1–20 mm.

The classification of drills depending on their length and diameter is regulated by the provisions of several regulatory documents– GOST 4010-77, 10902-77, 886-77.

How to understand the markings

Markings help you choose the right tool for drilling metal products. It's not difficult to figure it out. The marking of drills depending on their working diameter contains the following information about the presented tool.

• Miniature products, the diameter of which does not exceed 2 mm, are not marked at all.
• The markings of drills, the diameter of which is in the range of 2–3 mm, contain information about the grade of steel from which they are made, as well as the size of their cross-section.
• The marking of metal drills with a diameter of 3 mm or more contains the following data: working diameter, steel grade, and an imprint of the manufacturer’s logo.

By the alphanumeric designation of the grade of the manufacturing material, you can get an idea not only of the category of such an alloy, but also of the content of additional substances in its chemical composition.

Thus, the letter “P” in the marking of metal drills means that they are made of high-speed steel. The composition of steel alloys used in the manufacture of drills for metal work may contain additional substances that improve them performance characteristics. Such substances, in particular, can be molybdenum, which is designated by the letter “M,” and cobalt, designated in the labeling by the letter “K.”

Foreign manufacturers include more detailed information about the presented instrument in the labeling. Having decided to purchase such drills, you will receive the following data from their markings:

• name of the country of origin;
• manufacturer's trademark;
• steel alloy grade;
• working diameter of the tool;
• accuracy class;
• short recommendations on materials that such a tool can drill.

Popular brands of instruments from foreign manufacturers

In order to know, when choosing foreign-made drills, which ones are better suited for solving certain technological problems, it is enough to have an idea of ​​the material that will be processed with their help. Thus, foreign manufacturers give the following recommendations for choosing a tool with a certain marking.

Using tools marked as follows, it is recommended to drill:

• steel parts manufactured by simple casting and injection molding; products made of carbon and, the strength of which does not exceed 900 N/mm 2;
• products made of metal alloys containing aluminum, graphite, copper, nickel, zinc (bronze, brass, cupronickel, etc.);
• blanks made of gray and malleable cast iron.

Drills with this marking can be used for processing metals whose strength reaches 1100 N/mm 2. Such metals, in particular, can be the following steels:

• carbon;
• stainless;
• thermally improved;
• acid-, heat- and heat-resistant;
• alloyed.

If such a designation is present on metal drills, this means that titanium-aluminum-nitride coating is applied to their working part. This coating significantly increases the resistance of drills not only to corrosion, but also to wear, which helps to increase their service life. Tools with this marking can also be used for processing metals and alloys with strength reaching up to 1100 N/mm 2. Manufacturers recommend using the following types of drills for processing:

• malleable and gray cast iron, in the structure of which graphite inclusions have a spherical shape;
• copper-based alloys (brass, bronze, cupronickel);
• steel blanks produced by casting (including injection molding).

The best manufacturers

When choosing a tool for creating holes in metal, it is important not only to know what types of drills there are, but also to understand the brands presented on the domestic market. Both its durability and the results of the processing that will be performed with its help depend on who exactly made the drill.

• enterprises that produced drills in the territory of the former Soviet Union(their products, of which there are fewer on the market every year, are different high strength, reliability, wear resistance and, accordingly, durability);
• Ruko (drills produced under this brand can be made with cross sharpening and various types spraying and are characterized by an excellent price-quality ratio);
• Bosch (the brand itself under which such drills are produced already says a lot about their exceptional high quality and reliability);
• Haisser (drills of this brand, due to the peculiarities of their design and the use of special alloys for their manufacture, are able to successfully cope with their tasks even under extreme loads);
• “Bison” (under this domestic brand, affordable, but high-quality and reliable drills for metal work are produced).

How to sharpen

In order to efficiently sharpen a drill if its cutting part becomes dull, you must adhere to the following recommendations.

Choosing a tool for apartment renovation. Choosing the right drills.

A drill is a universal tool that you simply cannot do without when carrying out repairs of all kinds of complexity. Today there are many types of drills, and therefore it is very important not to make a mistake and make right choice, so that later you don’t have to replace, or even simply throw away such a tool in case of its premature failure. The site will tell you how to make the right choice.

Essentially all drills differ only in their appearance (diameter and length), as well as the material for which they are designed to work and, as a result, sharpened. Accordingly, it is necessary to initially select the size of the drill (it is necessary that such a tool matches the thickness of the material that will be drilled, or self-tapping screws, anchors, etc.). Next, you should select drills depending on the work that will be carried out.

Selecting a drill for metal

Metal drills differ from conventional drills (meaning those used for wood processing) in their versatility. Such a tool is indispensable when working with metals and can be used to create holes in alloyed and unalloyed steels, cermets, cast iron and non-ferrous metals.

The most common today are twist drills for metal. As a rule, such metal drills are a cylindrical rod in which two helical grooves are made, forming cutting edges. These grooves are made at an angle of 10-45° to the axis of the cutting tool.

You should also pay attention to the material from which the drill is made. Today, the highest quality tools for metal processing are made from high-speed steel (for example, R6M5) or alloy steel (9ХС). Such drills have increased durability and strength, and also make it possible to achieve maximum results in the process.

Choosing a drill for concrete

Concrete is a strong and powerful material, which is very difficult to process, especially to drill a hole. As a rule, special drills tipped with tungsten and cobalt hard alloy (“win”) are used for drilling concrete. Moreover, thanks to the use modern technologies In the manufacture of cutting tools, drills made from modified tungsten-cobalt alloys have appeared on the market.

For processing brick or concrete, drills with soft or medium soft tips are used. In the same case, if you need to process granite or other hard materials (for example, the same tile), then you simply cannot do without the use of Pobedit drills with plates of medium and high hardness (in addition, a series of teeth and reverse sharpening are performed on them).

Wood drill bits: how to choose?

For wood processing modern market offers the widest selection of highly specialized cutting tools. In particular, it is simply impossible to imagine working with wood without the use of three main types of drills:

• Twist drills are a sharply sharpened metal spiral that is used to create holes in wood of small diameter (8-28 mm) but quite significant depth (300-600 mm). Thanks to its spiral shape, such a tool is very easy to remove from working area after completion of work.
• Feather drills, as a rule, are used in cases where it is necessary to create any blind hole in wood with a diameter of 10 mm or more. It should be noted that such a drill can only be used to create holes, since due to the absence of cutting edges on the side surface, it is simply impossible to drill out what is already there.
• Cylindrical (ring, core) drills are widely used to create large diameter holes (from 26 mm). The main advantage of using such drills is the ability to obtain a neat hole without scoring or other defects, as well as high processing efficiency.

When choosing drills for work, you need to pay attention to their appearance. Tool if we're talking about about really high quality, should not have chips, dents, scratches or other defects. The cutting edges must be well sharpened along the entire length and have a uniform color.

When choosing drills, regardless of the material for which they are intended for processing, you need to pay attention to their color - it is easy to determine from it the finishing hardening treatment that was carried out:

1. Steel gray – no treatment carried out.
2. Black – the drill has been treated with superheated steam to harden it.
3. Golden – the drill has been processed and tempered for removal internal stresses metal
4. Bright gold – a layer of titanium nitride is applied to the surface of the instrument, designed to strengthen it and extend its service life.

It would not be amiss to note the fact that when choosing a drill, you also need to pay attention to the manufacturer. It is best to give preference to famous companies that have been on the market for more than one year. Only in this case can you avoid counterfeits and unnecessary waste of money.

Metal drilling is process, aimed at producing holes of various diameters in metal sheets and workpieces using a special rotating tool called a drill.

For drill manufacturing Hard materials that do not collapse under mechanical influence are used, most often these are high-speed alloy alloys. Depending on the type and thickness of the material, the diameter of the hole and the technological requirements for the processing method, metal drills can be:

• spiral;
• feathers.

Each type of tool has its own advantages and disadvantages, which significantly affect the ability to perform certain works, details about all these types.

Key indicators for selection

When choosing a tool for drilling metals, you must consider:

• the composition of the alloy from which they were made;
• way additional processing and the presence of surface coating;
• manufacturer's trademark;
• diameter and design shape;
• design and sharpening angles of cutting edges.

Important! The cutting part of traditional twist drills has a front and rear angle of inclination of the plane of the cutting part. The geometric parameters of the rear sharpening angle determine the magnitude of the friction force during operation and the wear rate of the tool. Increasing this indicator allows you to process stronger metals, but leads to reduced heat dissipation and faster wear.

What can color say?

An important external parameter when choosing a drill can be the color of the surface, which indicates the composition of the alloy, the processing method and the surface reinforcing coating. Quality tool made from high-speed alloys with the addition of titanium, molybdenum or tungsten. The international designation for such metals is HSS (High Speed ​​Steel).

However, even if the drill marking contains a similar inscription, but its surface is gray steel, you should not buy such a product. It was not subject to additional types processing and does not have sufficient strength and wear resistance. The price in this case will be low, but it will also last a short time, with the need for frequent sharpening.

Drills can be:

1. Black, after heat treatment with superheated steam and additional hardening. The cost of a black drill is slightly higher than that of untreated products, but it is quite affordable for use for domestic purposes. But increased strength significantly increases service life.
2. After heating the finished drills in a furnace and gradually tempering the metal to relieve internal stresses, the surface acquires light yellow tint. As a result, the wear resistance of the drill increases significantly, and its sharpening is required much less frequently.
3. Bright golden color talk about the use of an alloy with the addition of titanium, which has maximum strength. These are the most expensive drills, but their use is fully justified by their long service life.
4. Gray indicates low quality of the instrument. Used for one-time work, after which it is thrown away. Accordingly, this drill is the cheapest on the market.

When determining which drill will be best for your conditions, approach the issue from a practical point of view. For constant drilling work, it is better to buy an expensive, but more wear-resistant tool. But for periodic use and solving everyday problems, black or pale yellow drills are quite suitable. This will allow you to get the desired result at the minimum acceptable cost.

How drills are made and why they are different colors, video from the RUKO plant (Germany)

Marking of drills for metal, what you need to consider when choosing

The alphanumeric designations printed on the drill contain information about:

• diameter and length of the tool;
• the brand of metal from which it is made;
• method of additional processing and the presence of surface coating;
• manufacturing accuracy class.

At the same time, diameters up to 3.0 mm are not marked, and all the necessary information is given on the packaging.

The area of ​​application can be indicated by the following symbols:

• HSS-G for drilling mild steel, cast iron and non-ferrous metals;
• HSS-E for high alloy and stainless alloys;
• HSS-TiAIN is a universal tool for all types of materials.

The presence of such markings indicates the possibility of professional use of the tool.

How to choose the right drill for metal and other materials

Classification by length and diameter

According to the ratio of length and diameter, the tool differs in:

1. Short drills, 20-131 mm long, their diameter is in the range of 0.3-20 mm.
2. Elongated, length is 19-205 mm, diameter - 0.3-20 mm.
3. Long with a length of 56-254 mm. and diameter 1-20 mm.

TOP 10 most famous manufacturers

The manufacturer's brand is also a very important factor influencing the right choice. Well-known manufacturers of drilling tools guarantee the strength of the alloy, the quality of sharpening, high wear resistance and corrosion resistance. Therefore, if you are looking for a high-quality metal drill, you won’t be able to save money. The cost of well-known brands is quite high.

An exception to this rule may be rare drills made in the USSR. Having seen such a tool, you can have no doubt about its quality. Experts unequivocally speak about the excellent performance of Soviet tools in terms of alloy strength, long service life and stability of cutting edges. This is also due to the GOST requirements of that time for such a tool.

Among the ten best manufacturers of drilling tools, experts name:

1. European concern Bosch, producing drills made of high-strength high-speed steel with a surface coating of titanium nitride with a tensile strength of up to 900 N/mm 2. Can be used for drilling any metals except aluminum and its alloys. The cost of a drill depends on its diameter and length. A set of 12 pieces costs an average of 3,000 rubles.
2. Trade brand " Attack", distinguished not only by high quality products, but also by affordable prices. They are made from high-quality steel alloys that can provide long service life even under conditions of high-speed metal processing. The average cost of one drill is less than 100 rubles. 5500 – 7000 Cost of a set for professional use.
3. Wurth Zebra Spiralbohrersatz HSS is one of the best twist drills for metal working. Capable of providing the ability to drill at high drive speeds, while guaranteeing high edge quality and dimensional accuracy. Used for drilling structural steel and all types of cast iron. Can be installed on stationary drilling machines and hand-held electric drills. The average cost of diameters up to 12 mm does not exceed 120 rubles per piece.
4. Sets of the Russian brand " Anchor" The set consists of 19 items with a diameter of 1-10 mm and costs an average of 1000 rubles, therefore it belongs to the group of inexpensive high-quality tools. The durability and reliability of the drill is ensured by the presence of a tip made of high-strength high-speed alloy.
5. German brand Metabo Bestler produces a spiral-shaped tool with the cutting edge sharpened at an angle of 135 degrees. This condition makes it possible to achieve high drilling accuracy even at any rotation speed. The average price for a diameter of up to 12 mm is 100-120 rubles.
6. AEG HSS are considered the best metal drills in an affordable price category. Special sharpening of the tool does not require preliminary punching on the metal surface, which greatly simplifies the work process. Designed for drilling alloy steels with a tensile strength of more than 1000 N/mm 2.
7. Russian brand drills « BISON» (ZUBR) are used for processing all types of steels and ferrous alloys. Special cross-shaped sharpening ensures self-centering of the tool and high drilling accuracy. A set of 20 items costs 1000 rubles.
8. Sets DeWALT can be used in production and at home. The special design of the drill completely eliminates the possibility of damage and defects along the edges of the hole. A tool set of 28 items with a diameter of 1-13 mm costs up to 5,000 rubles.
9. Surface of Hawera drills from a European company Bohler coated with titanium nitride, which increases their strength and wear resistance. In addition, all products are subjected to special grinding, which guarantees drilling quality at any drive rotation speed. However, a set of 20 items can cost up to 6,000 rubles.
10. Irwin TurboMax belongs to the category of universal tools, designed not only for processing metals, but also plastics, wood, gypsum and other materials. When drilling alloy and stainless steels, a mandatory supply of coolant is required. The cost of a set of 15 drills is about 3,000 rubles.

As can be seen from the above list, the drills offered for sale differ in their characteristics, purpose and price. The manufacturer's rating also determines the quality of the products, which is usually confirmed by a large number of positive reviews.

Very often, home craftsmen and professional craftsmen use a variety of tools in their work. Most often they use a drill and drill bits. After all, to obtain a hole of the required diameter, you simply cannot do without such a tool.

When it is necessary to assemble any structure, you have to use special sets of drills. They include different types and designs. Each set is designed for a specific job.

Of course, you always need to know which drill is reliable and durable, and which one is better to choose for a certain type of work.

How to choose a drill for metal processing?

You can determine which tool is best for working with metal if you adhere to certain criteria. You need to know the characteristics, they must meet certain requirements:

1. Form;
2. Diameter;
3. Purpose;
4. Possibilities
5. Manufacturer.

Hue

Quality is primarily determined by appearance. In the first place, in this case, is its color.

Grey

A part with this shade is one of the most vulnerable. It has not been subjected to any treatment to increase its resistance to combustion and possible deformation. Its cost is low. It may not be enough even to complete one technological task.

Black

This is the color of instruments that have been treated with superheated steam. As a result, strength and service life have increased. Their cost is much higher, but remains within the range of availability.

Pale golden color

These tools were tempered during manufacture. The purpose of this treatment is to reduce internal stress, after hardening the metal, increase strength.

Bright golden hue

One of the most expensive instruments, as they contain titanium. Due to this, the drills have very high strength. The service life of such a tool is measured in years.

Drill sizes

To drill a hole in metal parts, each manufacturer produces a tool with parameters that may differ from the dimensions of other manufacturers.

However, there is GOST, which provides a complete classification of drills. All tools are divided into groups:

Short, having a minimum diameter of 0.3 mm and a maximum of 20 mm. In this case, the length is in the range of 20 - 131 mm.

Elongated. The diameter is exactly the same as the short ones, but the maximum length can reach 205 mm.

Long ones have a minimum diameter of 1 mm, and a maximum of 20 mm. The length of the tool ranges from 56 to 254 mm.

Drill materials and their markings

In order to know how to choose metal drills correctly and competently, you need to know what kind of metal will be processed. Only under this condition will it be possible to make the right choice. The instrument marking includes such data.

HSS-R and HSS-G

This tool can be used to process steel with a strength of up to 900 N/mm². Easy to work with non-ferrous metals. This drill is suitable for malleable and gray cast iron.

HSS-G Co 5

This marking indicates strength - 1100 N/mm². Holes can be made in most types of steel. For example, stainless steel, alloy steel, carbon steel, and so on.

HSS-G TiAN/TiN

To drill a hole in titanium, the tool is coated with a special coating, which includes:

1. Titanium;
2. Aluminum;
3. Nitride.

The surface becomes resistant to corrosion, cuts metal easily, and retains its original appearance for a long time. With this tool, holes are drilled in metal, the strength of which reaches 1100 N/mm². The list of processed metals and alloys includes:

1. Gray cast iron;
2. Bronze;
3. Brass;
4. Cupronickel.

In addition to the listed steel grades, other chemicals are also used in production. One of them is cobalt. It gives the tool high strength, resistance to deformation and thermal effects.

Carbide drills are located in a separate group. It must be said that each manufacturer chooses the material for the manufacture of such tools according to its own technological process. The main advantage is the ability to process workpieces that are thick and made of very hard alloys. The drill has an acute sharpening angle, due to which the labor intensity of the work is reduced.

Today, you can see a huge range of such tools on the market. The fact is that it is used not only for working with metal. It can also be used to process other materials:

1. Wood;
2. Ceramics;
3. Plexiglas;
4. Plastic;
5. Concrete.

Flat drills

They have an interesting name - feather ones. They differ in the shape of the sharpening. Main the advantages are:

1. When working, do not allow distortions;
2. Very simple design;
3. Low cost.

Negative characteristics include a decrease in diameter during sharpening; chips are not automatically removed from the hole.

A variety of such tools are cone drills. The minimum cross-section is 6 mm, and the maximum reaches 60 mm. They are usually used to operate special equipment. This can be a two-handed drill or a stationary drilling machine. The shank has a conical shape. Using such a tool, large cross-section holes are produced.

This type is the most popular. Tool has a cylindrical appearance, and deepening grooves are laid along the surface. They are specially designed so that during operation the chips are discharged outward. Depending on the type of shank, twist drills are divided into several types:

Ordinary cylindrical. The diameter of the drill for metal is no more than 12 mm. They are used in everyday life and at work.

Core drills. This tool is used to produce large holes whose diameter exceeds 30 mm. This tip has the appearance of a crown, on which teeth are often located. This tool is best used to process thin metal.

Threaded drills. Their direct purpose is to obtain a hole for cutting threads. The diameter of the tool should be a millimeter smaller than the size of the hole.

Step drills. A universal tool that allows you to simultaneously produce a hole with several diameters. They are mainly used when processing sheets with a thickness of no more than 2 mm.

Left hand drills. This tool was specially created for unscrewing hardware:

1. Shurupov;
2. Screws;
3. Bolts;
4. Self-tapping screws.

High precision drills. Designed to receive especially precise hole. The cost depends on the accuracy class; the higher, the more expensive.

In conclusion, I would like to give a little advice. When choosing the best drill, pay attention to all the above criteria. They will help you make the right choice so that you can use the tool for a long time in the future and always get the desired result.