Which drill is the strongest for metal? Choosing the best metal drills

The need to process various metal products arises not only among professionals, but also among many home craftsmen. When performing such processing, one cannot do without special tools, one of which is a metal drill. On 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 ​​the design features of 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

Flat

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;
• Not high price.

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

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

Spiral

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 metal work general purpose. 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 hand twist drills with very limited applications. You cannot do without them in cases where it is necessary to drill a bolt with a broken head out of a threaded hole or fastener, which 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 good, but excellent result 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.

Crowned

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.

Conical

This category includes tools with smooth and stepped work 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.

Cobalt

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

Carbide

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 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. Yes, different drill colors for metal means the following.

Grey

This color has the surface of drills that are of the lowest quality and, accordingly, the lowest cost. Instruments with a surface of this color are not subject to any additional processing, which 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.

Black

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.

Light golden

This color means that the drill has undergone a tempering procedure after manufacturing. Such 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.

Bright golden

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 the drills are made, when using them, the level of friction is reduced, which has a positive effect on the duration of their drills. efficient 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. Choose more affordable types of drills, the surface of which is painted black or light golden color, it is advisable in cases where it is necessary to perform one-time work related to metal drilling.

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 such diversity, the corresponding regulatory document (GOST) provides for the division of metal drills into various 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. Steel alloys used in the manufacture of drills for metal work may contain additional substances that improve their 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 tool 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.

HSS-R and HSS-G

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.

HSS-G Co 5

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.

HSS-G TiAN/TiN

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 distinguished by high strength, reliability, wear resistance and, accordingly, durability);
• Ruko (drills produced under this brand can be manufactured with cross sharpening and various types of coating and are characterized by an excellent price-quality ratio);
• Bosch (the very brand under which such drills are produced already says a lot about their exceptionally 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.

The Hand Tools company offers to buy metal drills from RESOLUX. Products manufactured under this brand are created for comfortable work and making the most accurate holes in metal.

Depending on the standard, materials, characteristics, cost and production method, there are different types of tools.

According to GOST 10902-77, in terms of quality and price, medium series drills with a cylindrical shank RESOLUX are divided into three groups:

1. Rolled drills R6M5 with the following characteristics:

• working part - polished;
• accuracy class B1;
• 1 - 20 mm;

Drills are mounted in three-jaw chucks of machine tools or hand drills. Manufactured in sizes starting from 13 mm. In this case, the shank is ground down to 13 mm, due to which a drill with a diameter of 16 mm can be fixed in a 13 mm chuck.

2. Drills for stainless steel P9 with the following characteristics:

• working part - polished;
• accuracy class B1;
• 1 - 13 mm.

Tools allow you to maximum efficiency process stainless steel, structural and other difficult-to-process steel grades. They are located in the middle price segment.

3. Drills R6M5 with accuracy class A1

This professional tools, widely in demand for production needs, at enterprises where increased demands are placed on the properties and characteristics of products, as well as on the precision of drilling.
In the production of tools in this series, high-quality steel grade R6M5 and the grinding method are used.
Suggested sizes: 1 - 13 mm.

Rolled drills are the most attractive in price, as they are made in the simplest and most accessible method. The low cost of the rolling method is explained by the high speed and automation of production:

• at the first stage, special blanks are made from rods;

• then they are heated and pulled through, due to which the working part, similar to a spiral, is formed;

• the workpieces are carefully ground and sharpened.

Grinding a working spiral from a single piece is the most expensive production method. The reasons for this: low production speeds, the most careful processing and, as a consequence, highest quality products.

Drills with a conical shank are produced by milling. Since complete automation of the process is impossible due to the large size of the workpieces, it requires a lot of time.

You can buy long and elongated drills with a conical or cylindrical shank from the Hand Tools company in Moscow. For more information about prices for metal drills, please call.

Everyone knows why a drill is needed - to drill holes. Many people know that drills are available for metal, wood and concrete. Some will be able to distinguish a Forstner drill from a feather drill. But progress does not stand still, and today there are dozens of types of drills on store shelves, differing both in design and material of manufacture, and in the features of application. And, of course, they also differ in prices.

A single metal drill can cost either 10 or 500 rubles, and at first glance there will be no difference between them. But the first one will get stuck in aluminum, overheat and become dull when drilling thick iron, and it simply won’t be able to drill stainless steel. In order not to throw money away when buying drills, you should clearly determine what material you need to drill and what characteristics of drills you should pay attention to when processing this material.

Drill characteristics.

View. Defines the drill design. There are the following types of drills:

Spiral (screw)- the most common type of drill. It is a metal cylinder with 2-4 helical spiral grooves that remove chips and reduce friction between the side surface of the drill and the walls of the hole. On one side, the drill is sharpened, forming – along the line of intersection of the sharpening and the front surfaces of the grooves – a cutting edge. On the opposite side there is a shank designed to secure the drill in a machine or drill. There is often a marking on the shank, which can sometimes be used to determine the material of the drill and its performance characteristics. On Russian (and Chinese for Russia) drills, the steel grade must be indicated; on foreign-made drills, the marking may be different; most often, HSS (High Speed ​​Steel) is mentioned.

Lewis spiral or auger drill – differs from a twist drill in the number of spiral grooves (there is only one) and the cutting part with a centering tip. The tip has a threaded thread that allows the drill to penetrate into the wood independently without pressing on the drill. These drills are designed for making deep through holes of medium diameter. Holes drilled with a Lewis spiral have a smooth inner surface. The disadvantages include the high cost of such drills, the tendency to move away from the axis and to jam. Also, such drills are quite fragile.

To prevent deviation from the axis, we can recommend preliminary drilling to the maximum accessible depth with an ordinary thin (no thicker than the centering tip) drill. Up to this depth, the Lewis spiral will go in the desired direction, then the direction will be maintained by fixing the drill in the already drilled hole.

To prevent jamming, you should drill at low speeds; the power of the drill should correspond to the diameter of the drill and the drilling depth. For Lewis spirals with a diameter of more than 30 mm, drills with constant electronics, additional handles, power from 1500 W and high torque are recommended.

Feather drill has a flat working part with two cutting edges separated by a centering tip. Behind the working part there is a shank, which is a relatively long and thin rod. Such drills are used for drilling large diameter holes (12-55 mm) in wood. The advantages of feather drills include ease of use and low price. In addition, deep holes with a diameter of 35-55 mm can only be drilled with such drills. There are also plenty of disadvantages:
- there is no chip removal, the drill must be frequently removed and chips removed from the hole
- the drill is prone to moving away from the axis and to drilling non-straightness; pre-drilling a pilot hole helps little
- the edges of the hole are rough, uneven
- it is impossible to drill a hole with a diameter larger than the maximum diameter of the centering tip
- the diameter and shape of the hole are not maintained accurately

Forstner drill allows you to make neat holes of large (20-40 mm) diameter in wood. Accurate cutting is ensured complex design cutting part, containing, in addition to two cutting edges, also radial cutters in a circle, cutting wood fibers before removing them with cutting edges. Two inclined channels in the cutting part remove chips. The drill is fixed in the hole due to the tight fit of the walls of the cutting part to the wood, which ensures straightness of drilling. The result is perfect round hole with a flat, even bottom (except for the recess from the guide pin) and smooth edges. The neatness of the holes allows you to use a Forstner drill in furniture making.
The disadvantages of Forstner drills include their high cost and the inability to drill holes.

Step drills They are a set of cutting parts of different diameters on one rod, arranged in increasing diameter. Designed for drilling sheet material thickness 1-8 mm. The maximum material thickness is determined by the height of one cutting part of the step drill. The main advantages of a step drill are accurate centering and neat hole edges; even when drilling large diameter holes in thin sheets. If you try to drill through a thin sheet with a large-diameter drill, the material will most likely be damaged and the center will not be able to be accurately maintained. Previously, such holes were drilled using a set of twist drills, gradually increasing the diameter. Step drill does the same thing, but without changing the tool. Also, the advantages of step drills are their versatility (with one drill you can drill holes of different diameters) and the ability to chamfer simultaneously with drilling. The disadvantages are the high price and limited thickness of the drilled material, determined by the height of the “step”

U milling drill there are sharp notches on the side edges, with the help of which it is capable of milling sheet material that is not too thick. Who among the craftsmen has not broken a drill while trying to widen a drilled hole by moving the drill along the surface? Conventional twist drills do not like this, and the effect is usually far from ideal - the grooves of twist drills are not suitable for milling. But with a milling drill, such a trick can be pulled off. Certainly, hand router such a drill will not replace it - its productivity is low, and the quality of the cut leaves much to be desired. But for expansion drilled hole or for drilling oval holes it is perfect. Disadvantages of a milling drill:
- it is difficult to mill grooves: the lower part of the milling drill is a regular twist drill, and if the hole is not through, then this part will interfere with milling.
- the thickness of the processed material is limited by the length of the milling part
- the load created by such a drill during milling is harmful to the drill bearings - you should move the drill along the surface slowly, with measured force, otherwise there is a danger of damaging the drill.

Centering punch- this is not a drill, but a device for accurately marking the installation locations of dowels in furniture parts. The punch is tightly inserted with the blunt part into the finished hole for the dowel (for this, a punch of suitable diameter is selected from the set), the part is applied to the one being connected exactly as they should be connected, and with a light blow on the first part, a mark is left on the second for drilling a counter hole for the dowel. This is the most accurate way to manually drill dowel holes.

Purpose of the drill determines what material it is intended for drilling.

Metal drills can be spiral, stepped and milling.
Metal drills must be made of high-speed steel. The marking on the drill should indicate this. If there are no markings on the drill, you should treat such a product with caution, especially if it has a low price. There are a large number of cheap low-quality steel drills on sale that are unable to drill a hole even in thin iron, let alone in stronger metals. If there is a marking, it can tell you what metals can be drilled with this drill.

Russian-made drills	Foreign drills	Properties
M1	HSS, HSS-R	Basic metal drills. Low price, satisfactory wear resistance. For drilling iron to a shallow depth. Low resistance to impact and overheating.
M2, P6M5	HSS-G	Drills for the widest range of applications. Increased wear resistance and strength. For drilling iron to any depth, as well as sheets of alloy and carbon steels, cast iron, non-ferrous metals. Increased resistance to impact.
M35, R6M5K5	HSS-E, HSS Co	Drills for difficult operating conditions. Increased hardness and wear resistance, increased resistance to high temperatures. Suitable for drilling stainless steel.
-	HSS-G TiN, HSS-G TiAlN	Drills coated with titanium nitride or titanium-aluminum-nitride. Maximum hardness and heat resistance. Designed for special drilling durable metals, titanium alloys. The price is high, sharpening is not allowed.

You can also get some idea of ​​the purpose of the drill by looking at the sharpening angle. An acute sharpening angle (80-90°) indicates that the drill is intended for soft metals. The most common sharpening angles are in the range of 100-120° - for drills for drilling steel and cast iron. Drills for drilling the hardest metals have a sharpening angle of 130-140°.

Wood drill There can be a twist and a feather drill, a Forstner drill, a Lewis spiral, as well as a step and milling drill. A twist drill for wood has a special type of sharpening of the cutting part - a centering spike is formed in the center of the drill during sharpening - it is designed to accurately center the drill at the selected point. You can drill into wood with a metal drill, but due to the uneven hardness of the wood, at the beginning of drilling the drill may move to the side - to where the wood is softer. Therefore, if precision drilling is required, it is better to drill with a specialized wood drill.

Drills for brick and concrete most often they are spiral and have a soldering of pobedite at the end of the cutting part ( composite material increased hardness). When purchasing such a drill, you should choose products from trusted manufacturers, such as Bosch or Makita - Pobedit drills are inexpensive and such a purchase will not cause much damage to your wallet, but it will save you from buying a low-quality Chinese drill, which is not like a concrete drill. plaster wall won't really drill. At the same time, it should be borne in mind that it will be problematic to drill a hole of large diameter (more than 6 mm) and/or great depth in concrete even with the highest quality drill - even impact drill. If you need to make more than one or two such holes, they must be made exclusively with a hammer drill.

Spiral stone drills They are similar to drills for brick/concrete and differ only in the larger sharpening angle of the Pobedit cutting tip. Most often, such drills are universal and can drill both stone, brick or concrete. Another thing is that the productivity of such drills can be depressingly low - natural stone stronger than concrete and drilling a single hole can take tens of minutes.

A high-quality metal drill is capable of drilling many different holes in the hardest materials without becoming dull or breaking. Tall performance characteristics you can expect from a drill if it is correctly selected for the product being drilled, made of quality material and sharpened as necessary.

Let us consider in detail the types of metal drills, their characteristics, features of use and criteria for choosing a cutting tool.

A metal drill is an indispensable tool for a modern builder

A metal drill is used for cutting holes in alloyed and unalloyed steel, its alloys, non-ferrous metals, cast iron and other types of metal. Often such drills are used when working with hard plastic materials. The scope of metal drills is limitless: the tool is used in the most different areas activities and in everyday life.

It is difficult for an ordinary buyer to navigate among the wide range of drills that are presented on the construction market today. Without competent consultation from a specialist, choosing a suitable model is quite difficult.

Structurally, a metal drill has a working part (cutting and calibrating part) and a shank.

Metal drills belong to the category of spiral drills, since they have spiral-shaped grooves along the entire length for removing chips

The place at the end of the drill is the cutting part, where the pointed edges are located to ensure the penetration of the drill into the material. Behind the cutting part there is a calibrating part equipped with grooves for removing metal chips. The calibrating part is responsible for the smoothness of the edges of the hole and sets the desired diameter.

The material of manufacture and the structure of the working part determine the purpose of the cutting tool.

Attaching the drill to hand tools or machine tool occurs through a shank, which can have a conical, cylindrical or hexagonal shape.

Classification of drills for metal

Depending on design features, metal drills can be divided into the following types:

Features of marking drills for metal

When choosing a drill for metal, you need to pay attention to its markings, which may indicate the diameter, steel grade, accuracy class and manufacturer.

Drills with a diameter of up to 2 mm are not marked, on products up to 3 mm the diameter and grade of steel are indicated, and on drills of large sizes more extensive information may be indicated.

Basic designations:

• marking starting with a letter R indicates high-speed steel products;
• numerical values ​​determine the content of a particular substance in the alloy, for example: K6- six parts of cobalt (increases the heat resistance of products); M4- molybdenum content;
• for comparison, a drill with markings R6M5K5 much stronger than a drill with markings R6M 5, due to the addition of cobalt (the price of reinforced cobalt drills is higher than conventional ones);
• imported analogues have designations H.S.S. or Din; an HSS drill for metal usually has additional markings of Latin letters indicating the working material ( HSS-G drill alloy and carbon steels, aluminum and copper alloys, cast iron; HSS-E in addition to the materials listed, they will cope with acid-resistant and stainless steel; HSS-G Tin- especially durable, suitable for drilling titanium alloy).

For the manufacture of drills for metal, GOST regulates the use of tool high-speed steel grade P18

What can the color of a drill tell you?

The method of final processing of the drill will play an important role in ensuring the strength and reliability of the tool. The color of the drill indicates what materials were used to process the product.

Gray indicates that the drill could not be processed in any way. This is the cheapest and least stable product, which will not cope with all types of metal and will not last long.

Black the drill acquires after treatment with superheated steam - this increases the service life of the product.

Dull golden hue- a sign of using tempering to relieve internal stress in hardened metal. This procedure reduces the fragility of the hardened drill, giving the material strength.

Rich golden color have drills coated with titanium nitrite - this ensures the highest wear resistance. These drills are the most convenient to use (reduced friction) and durable, the only drawback is their high cost.

Proper sharpening of a drill: the need for the process and the algorithm of actions

A high-quality drill is designed for long-term use, however, it can become dull over time. Of course, you can replace it with a new one, or you can avoid unnecessary expenses and sharpen the drill yourself.

In everyday life, for household needs, drills with a diameter of up to 16 mm are usually used, which can be sharpened on a regular sharpening wheel without resorting to “high technology”. If you don’t have a sharpener, you can use a grinder or electric drill, which must be secured before work.

Before you start sharpening a metal drill, you need to prepare:

• eyes must be protected with goggles, hands with gloves;
• prepare a small container for coolant (machine oil, water) - if the drill is not cooled periodically, the metal will overheat and will not be able to withstand high loads during drilling in the future.

The sequence of actions when sharpening a drill is as follows:

1. Pressing the drill tightly against the grinding wheel, we process the back surface of the tool. The sharpening angle should not change.
2. After finishing processing back surface a regular cone should form (you can see it by looking at the tip of the drill from the side).
3. While maintaining the sharpening angle, the working part of the drill is processed.
4. Finishing of the rear part of the tool occurs after processing the working part of the drill.
5. The size of the bridge at the tip of the drill should not be more than 0.4 mm (for drill diameters up to 8 mm) and no more than 1-1.5 mm for larger drills.

You should not concentrate only on the tip; the entire working surface must be sharpened. lateral surface drills

When sharpening for the first time, it is advisable to practice on old, worn-out drills in order to feel how to hold and press the tool correctly. If you insert a “test piece” into a drill and drill a couple of holes, it will immediately become clear where the error was made during processing.

When choosing drills for working with metal, you should adhere to the following recommendations:

With the right choice of tool and good sharpening, metal drills can be used for a long time and without problems, both for their intended purpose and for drilling holes in other materials: wood, plastic, plexiglass and stone.

Very often, home craftsmen and professional craftsmen use the most different instruments. Most often they use a drill and drill bits. After all, to get a hole 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. These 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 appearance. In first place, in in this case its color stands out.

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 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 do right choice. The instrument marking includes such data.

HSS-R and HSS-G

This tool can 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 instruments according to his own technological process. The main advantage is the ability to process workpieces that are thick and made of very hard alloys. The drill is different acute angle sharpening, due to which the labor intensity of the work is reduced.

Today, on the market you can see huge assortment such a tool. 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 for work special equipment. This can be a two-handed drill or a stationary one 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 cylindrical view , 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. Universal tool, allowing you to simultaneously obtain 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.

Drills high precision. 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 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.