Drills for metal marking designation. Which drills are better for metal: features of choice. Drill making method

Drilling metal products- an operation very familiar to home craftsmen. However, this process is simple at first glance. For successful work, you need to understand which drills are best to use and how to choose quality products. How to choose a drill for metal so that it does not become dull or break? Lots of questions to consider before purchasing. Next we'll look at types of drills for metal, their classification, markings, designations, and also provide photos of each type of metal drills.

Explanation of markings

Before you figure out what types of drills there are by model, you should pay attention to the markings. The designation is primarily influenced by the diameter. For thin products, marking is usually not provided; products starting from 3 mm are marked. As the thickness increases, the amount of information increases - accuracy classes, manufacturers, etc.

The alphanumeric designation is simply deciphered. Traditionally domestic products begin to be designated with the letter P, that is, high-speed steel. The next number indicates the percentage of tungsten. The following numbers and letters contain additional components and their quantities. So, K is cobalt, M is molybdenum. The greater the number of elements included, the best characteristics(temperature, mechanical load) has a drill.

Imported products are marked as follows: DIN and HSS.

DIN designates multi-purpose tools suitable for general and deep drilling. They have different coatings, easily recognizable by color.

HSS have differences in the letters following the abbreviation. G - indicates the presence of a tool capable of handling carbon and alloy steel; it will process cast iron, aluminum, and copper alloy. E – a tool that can handle alloy/carbon steels, as well as acid-resistant and stainless metals.

Titanium steels are designated HSS-G TiN and HSS-G TiAlN. For them, any of the above metals will not be a hindrance.

Drills for household use

All types of metal drills can be divided into areas of application. So, we can distinguish between domestic and industrial use. The second direction involves use in specialized equipment - machines. Conventional ones can also be used in machine tools, but they are most widespread in portable power tools.

A drill for metal, as everyone is used to seeing it. Mainly made of high-speed steel HSS, P6M5. Sometimes you can find the highest quality ones made from P18 steel. Nowadays this steel is practically not used, but if you come across it, then this is a high-quality option.

The marking of metal drills of this type assumes the following modifications: P9, P18, P9K15. The letter P denotes high-speed steel construction. The numbers determine the percentage of tungsten in the tool. Subsequent letters and numbers determine the presence and quantity of alloying substances. For example, K6 means that the alloy contains 6 parts cobalt, which contributes to heat resistance. M4 – the presence of 4 parts of molybdenum.

With tapered shank. Most often intended for a drilling machine. The shank is made in the shape of a cone, the so-called Morse Cone, which is crimped into the chuck. There are drill models that support similar types of tools. In this case, they are simply inserted into the drill without the use of chucks. Similar models drills are low-speed. If it is necessary to drill holes large diameter(from 23 mm), then they are drilled with similar models.

The markings are similar to conventional spiral ones. The alphanumeric designation determines the presence of components and their relationship.

The classification of drills for metal also assumes this type. They are designed to create large diameter holes. They are similar to crowns for concrete work, but without carbide elements on the teeth. Manufactured from HSS steel. Has fine teeth. Perfect for creating holes larger than 30 mm in diameter. But it is only suitable for thin metal.

Crown models with a diameter of less than 2 mm are not marked; over 3 mm, the brand and thickness are indicated. At large sizes information about the manufacturer, steel composition and other characteristics is indicated. All data can be found on the packaging.

Step type (conical). This option was considered in detail. They became widespread relatively recently. The diameters of the holes can also be significant. However, you can create small ones. The tool has universal characteristics and the ability to drill from 6 to 30 mm.

A distinctive feature is that it can only be used with sheet metal up to 2 millimeters thick.

Centering. Also considered in detail. Necessary for centering the points for creating holes in workpieces before starting drilling. The table below will help you understand the notation.

Carbide modifications. Used for processing durable metal, including pasted metal. In this case, only this option can help. The tip has a carbide plate - alloy BK8 (win). Such tools have become widely known for drilling concrete. However, unlike the concrete analogue for metal, the sharpening angle is sharp, one-sided. This provides the ability to effectively process metal.

There is only one problem - they are rarely found on sale.

There is also a modification of drills that is not often found on sale. They are used for drilling broken bolts and screws that cannot be removed with an ordinary model.

With increased accuracy. Used in work with increased precision requirements. The marking of a drill of this type contains the designation A1, B1. These are accuracy class designations.

Discussed in detail in the article. IN Lately have become widespread and are sold everywhere. They have increased durability and allow processing particularly hard parts. How do cobalt drills differ from regular ones? Most often by markings. For example, the presence of the inscription P6M5K5 indicates the presence of cobalt in the composition, a reinforced structure. The cost is several times higher than regular ones.

Titanium coated. Easy to determine by yellow color. This is just the sputtering of titanium nitride. There is often controversy over the strength of cobalt and titanium drills. We can definitely say that cobalt is much stronger. The presence of a titanium coating provides cutting edges with protection from rust rather than from abrasion.

Drills used in machine tools

In addition to the well-known modifications, there are options that are known only to a narrow circle of specialists associated with professional metalworking.

Drills with brazed plates. Allows for increased wear resistance characteristics during processing of particularly durable metals. In addition, they are economically feasible when machining large holes, because the price is significantly lower than its carbide counterpart or with replaceable inserts.

Used for processing parts in mass/serial production. They are distinguished by a fast process of changing plates, which significantly simplifies the work of operators, because The drills do not need to be re-sharpened and reinstalled. They are used when processing blind holes with a flat bottom, as well as when there is a low requirement for processing accuracy.

For deep drilling. When machining holes up to 100 mm, the following modifications can be used.

• Preferred when drilling on a machine with a horizontal spindle layout ( lathe, machining center). Using similar drills - advanced technology creating a blind hole.

• Refers to outdated methods of creating blind holes. The processing accuracy can reach the ninth class, and the surface cleanliness is from 0.1 to 3.2 Ra microns.

These are the main types of drills that are used in everyday life and industry. There are also universal options, which can be used to treat any surface. WITH existing varieties drills for other materials can be found in the article “”.

Download GOST

Very often, home craftsmen and professional craftsmen use the most different instruments. 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. 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 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 do 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, others are also used in production. chemical substances. 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, 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 interesting name- feathers. 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 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 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 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.

Drills and drill bits are the most basic tools in household, and almost everyone has it, and those who don’t know where to get it. Sooner or later, everyone will have to use a drill. Or if with wood or even stone everything is more or less clear, and you can drill a hole, so to speak, by touch, by feeling, then with metal this will not work. This is a very stubborn material. Let's figure out which metal drills are better?

Drilling is an entire art that can be studied and improved: drilling angle, pressure, but most of all, experience and the tool decide.

The problem is that most drills are sold of poor quality, especially in the markets. It is better to order online or in specialized stores where you can see and touch the material.

What you need to know about metal drills

There are a huge variety of metal drills; in addition to the fact that you need to look at the quality, you also need to pay attention to the shape and color. The product is built from the following elements:

• The main (cutting) part, which performs cutting (drilling) of metal;
• Working surface. Its role is that when the main part is working, chips appear, which are removed by the working surface;

Expert opinion

Sergey Yurievich

The end, also called the shank, is attached to the drill chuck, and movement begins from it.

Metal drills come in many different shapes, each of which is used for a specific type of work.

Depending on the form, there are the following types:

The most common type known to everyone is spiral. In essence, it is a cylinder-shaped rod, and on the sides there are one or two spiral grooves (it is because of them that the chips are removed). In turn, twist drills have their own subtypes:

• increased accuracy, often chosen by craftsmen to make a hole perfectly, down to the millimeter;
• classic ones, the same ones cylindrical, which are common among both pros and ordinary users;
• narrow application, its spiral groove is wrapped to the left rather than to the right. It is used in cases where something needs to be drilled out.

Conical step drill. Unlike a cylindrical one, it can make holes of different diameters. Used to create new or expand existing holes.

Flat drill. As the name suggests, the working surface of this type is flat. The main disadvantage: due to its flatness, the chips are not automatically removed; you have to remove them manually. In addition, you cannot make large holes with this drill. But despite the huge disadvantages, they are in demand because they are very cheap and insensitive to distortions during drilling.

Core drills have different cylinder shapes, but the upper part is devoid of a base and the sides are covered with teeth, which are made of hard alloy or coated with diamond dusting. Used to create holes of different diameters.

The following types differ in that they are created specifically for hard metal, while the previous ones are not suitable for high-density metals - they will break.

• Cobalt. Can be confused with spiral, since it also has a spiral shape, but unlike it does not have a cylindrical base. In addition, thanks to cobalt, this type has high strength. But they are also expensive, so not everyone can afford them; before purchasing, evaluate the difficulty of the work.
• Carbide. They are caused by the presence of a carbide plate on the cutting part, due to which it can make holes in fairly dense metals.

These are the facts that can tell the shape and structure of the drill, but the color also matters:

• Rarely found, but still existing bright gold drill bits. This color indicates the presence of the hardest metal on the planet – titanium – in the alloy. Which goes without saying about the quality of the part and its strength and value.
• Light gold the color indicates that the product has undergone special thermal preparation. Not as durable and expensive as bright gold, but the price is quite high, not everyone can afford it.
• Drill black color processed with superheated steam, thereby increasing its strength. The golden mean of price and quality.
• WITH gray or metallic color– the most common and low-quality drills

Decide for what task you need a drill (what material needs to be drilled, what diameter of the hole), you can rely on this. Now you definitely won’t take a cobalt drill to make a small hole in thin sheet iron or vice versa.

Expert opinion

Sergey Yurievich

Construction of houses, extensions, terraces and verandas.

When choosing a product, look at the sharpening, its symmetry;

The manufacturer can also play a role; the drills can be identical, but from different companies, in which case choose a manufacturer that you know or have dealt with.
To determine the working diameter, look at the marking, since on products up to two millimeters it is not marked at all, from 2 to 3 mm only the company’s mark is placed, and on products from 3 mm both the manufacturer and the working diameter are marked, so you should pay attention to this.

The variety of drills for hardened metal is huge, so there is no point in choosing, looking on the forum for which one is better, it all depends only on two things: the task that needs to be completed and the size of your budget for the purchase.

Markings for metal drills are special designations that are indicated on the cutting tool. It is imperative to pay attention to all the indicated numbers and letters in the marking, as they indicate the diameter of the device, the grade of steel from which it is made, the accuracy class, as well as the country of origin or brand of manufacture. Drills that have a diameter less than 2 mm are not marked; products whose size is from 2 to 3 mm are marked with diameter and steel grade. If the cutting tool is large (more than 3 mm), then all possible parameters are indicated on it. It is necessary to know the marking features in order to select drills of the required size, since not all devices are suitable for drilling certain holes.

Twist drill markings: meaning of letters

Solid spiral cutting tools, made of high-speed steel, have the following grades: P 9, P18, P9K15. The letter P means that the product is made of high-speed steel. After the letter P there is a number that indicates the amount of tungsten that the tool contains. The average is taken. More letters and numbers follow. The numbers that are indicated after the letter indicate the content of the alloying substance in the alloy; this is a percentage parameter indicating the mass fraction of the substances. For example, if K6 is indicated, this indicates that the alloy contains six parts of cobalt, which helps to increase heat resistance. If M4, it means there are four parts of molybdenum. That is, after the letter P and the number, a special letter (the name of the element) and a number (the amount of the element present in the alloy) are indicated - this is the percentage content of the alloying element.

photo: markings twist drill for metal

For example, the following marking is indicated: Р6М5Ф3. This means that the drill is made of high-speed steel with the addition of 6 parts tungsten, 5 parts molybdenum and 3 parts vanadium.

Important: the labeling does not indicate the quantitative addition of chromium or carbon, since the first element has a stable parameter of 0.4%, and the second has a value equal to the vanadium content.

An example of a symbol for a spiral tool with cylindrical shank.

A device that has increased accuracy, diameter - 15 mm, version 1, accuracy class A, designated: 2300-7066 A1 GOST 886-77. This value indicates the accuracy class of the device. It can be A1 - increased accuracy or B1 - normal accuracy. 2300 – operational and design characteristics, 7066 – manufacturing serial number. GOST - in accordance with what standards the device is manufactured.

If you purchase an elongated spiral drill with a cylindrical shank, then AB 2300-0055 will be written on it. AB is the enterprise index, 2300 is the operational and design characteristic, 0055 is the serial number of the standard size of the device according to the factory standard.

An installation with a conical shank has an indicator of 2301, for solid ones it is necessary to indicate trademark manufacturer, diameter, grade of carbide, letter “T”, if the installation has increased accuracy.

Imported devices are designated HSS or DIN. The HSS device has an additional marking - a letter that indicates the working material. For example:

• HSS-Co (addition of cobalt);
• HSS-E (cobalt addition);
• HSS-G (addition of metal P4M3 - molybdenum);
• HSS-R (addition of metal P2M1 - molybdenum).

DIN drill markings have standard parameter 338 is a technical standard that fully complies with GOST 10902-77.

Center drill designation

The designation of centering drills is established according to GOST 14952-75. The designation has an additional letter A, B, C or R.

1. A and B indicate that the design is used for 60 degree openings and has (B) a safety cone or does not have one (A).
2. C – used for 75 degree holes without a safety cone.
3. R - for holes that have an arcuate shape.

photo: marking of a centering drill for metal

The installations have a designation, for example, 2317-0118 GOST 14952-75. 2317 is an operational and design characteristic, 0118 is the serial number of the standard size of the device according to the factory standard.

For example, if the number 0001 is indicated, then the diameter is 1 mm. Devices of group B have marking features. 2317-00-12 if this is the second version, and 2317-0113 if this is the first.

Group C is designated: 2317-0022 (second version), 2317-0124 (first), group R 2317-0027. This is if the diameter is 1 mm.

The marking of the p6m5 drill may not be indicated in this type of device.

Marking of the feather cutting tool

Strength is indicated:

1. P18 is a satisfactory indicator, increased grindability, indicating a wide range of quenching temperatures.
2. P 9 – characterized by increased wear resistance, a narrower range of hardening temperature indicators, and increased ductility.
3. P6M5 – molybdenum is additionally added, increasing the tendency to decarbonization.
4. R12F3 – have reduced grindability, used for drilling in medium mode. Added 3% vanadium.
5. R6M5F3 – increased wear resistance, work on average speed cutting, used for carbon and alloy tool steels.
6. R9K5, R6M5K5, R18K5F2 – cobalt is added, which provides increased secondary hardness, heat resistance, and increased cutting conditions.

They have the designation 2304 - operational and design characteristics. Full marking 2304-4001-50-108. The indicator from 50 to 108 may vary. It indicates the possible diameter value.

Conclusion

Each device must indicate the steel grade (P and number), additional elements included in the composition (M, K, F and the number - percentage), the diameter of the drilling part, as well as the trademark of the manufacturer. In order to choose the correct size device, pay attention to these parameters, as well as symbol designs.

Not only specialists, but also home craftsmen often have to process various metal products. And here you cannot do without special tools, in particular drills. And here the question arises about which metal drills are the best and how to choose them correctly.

Design and functional features

There are different types of metal drills, which differ from each other in functionality and design. Moreover, with the help of such devices it is possible to process not only the metal itself, but also other materials, for example:

• tree;
• ceramics;
• polymer materials;
• concrete;
• brick.

Design features must be taken into account material characteristics, which will be processed. When it comes to metal drills, they include such elements as:

• cutting part - performs key work;
• shank - with its help the tool is fixed in the equipment chuck;
• working surface - it is used to remove chips from the processing area.

Classification

Depending on the design, drills for metal products are:

• spiral;
• conical;
• crowned;
• flat.

Flat tools differ in the flat shape of the working part, they are also called feather ones. Their advantages are:

• lack of sensitivity to distortions;
• simple design;
• affordable price.

However, they also have their disadvantages:

• They cannot be used to drill large diameter holes.
• There is no automatic removal of chips from the processed area.

Spiral tools

Twist type drills are the most common. This tool has the shape cylindrical rod, the assembly of which contains spiral grooves, covering its entire working part. Thanks to them, chips are removed from the working area.

Depending on the design and scope of use, spiral instruments are divided into:

• Cylindrical - have general purpose. The diameter of the tools can reach 80 mm; they can be used for both home and industrial purposes.
• Left-handed - have a limited scope of use. They are needed primarily when you need to drill a bolt with a broken head from a threaded hole or fastener, which cannot be unscrewed in any other way.
• Tools of increased precision - they can be identified by the presence of the designation, A 1. With their help, you can make holes with the most accurate diameter.

Core and cone drills

Crown tools look like metal glass. On its end working part there are cutting teeth, with which you can make holes with large diameter. Such teeth can be diamond-coated or made from hard alloys.

Conical products have stepped and smooth work surface and are used to create holes of small thickness. They are able to provide easy centering of the hole at the beginning of work. Their key advantage- This ability to make holes of different diameters.

There are also other types of tools, thanks to which even the most highly durable materials can be processed. These are cobalt or carbide tools.

Cobalt tools made of high-speed steel, which has been alloyed with cobalt. This material gives high strength to the drill, thanks to which it is resistant to thermal or mechanical stress and deformation. They can be used to drill even high-strength and tough metals or alloys. The only drawback is the high price, which is compensated by technical characteristics.

If we talk about carbide structures, they differ in that they place carbide inserts, and the main part is made on the basis of tool steel. The plates are made on the basis of carbide alloys, which have high wear resistance and hardness. The cutting inserts will not need to be sharpened in the future, and with the help of such a tool you can drill particularly hard metals or alloys, as well as products with great thickness.

When choosing one option or another, you should know in advance where you will use it, and also take into account the characteristics of the material being processed. When purchasing, consider the following tool parameters:

• quality of sharpening and symmetry of structural elements;
• color;
• functional features;
• material characteristics;
• working diameter;
• compliance of the form with standard parameters.

When purchasing a metal drill, you need to take into account the features of the equipment with which it will work. For example, if you need to drill a large hole in a metal product, you need to take a powerful low-speed drill.

Surface color characteristics

The quality of products largely depends on the color of the surface. What does this or that color mean?

• Gray - such a tool is inexpensive and does not have the most better quality. It has not been subjected to additional treatments to help increase its hardness and resistance to burning or deformation. When drilling hard metals, such a drill may not be enough even for one hole.
• Black - the tool was treated with superheated steam, has increased strength and wear resistance. The cost is higher than the previous option, affordable for most buyers.
• Light golden - after manufacturing, the tool was subjected to a tempering procedure, during which residual stresses inside were eliminated and strength characteristics were improved.
• Bright golden - these instruments are the best, they contain titanium. During operation, the level of friction is reduced, thanks to which the service life is long. The disadvantage is the high cost.

When purchasing a drill of a particular shade, think about how often you will use it, and also take into account requirements for quality and accuracy of work.

So, if you plan to use them frequently and intensively for high-quality and precise work, then it is better to purchase bright golden models.

But if you buy cheaper options for this, then you will have to change them often, and in the end you will not save anything.

Dimensions

Manufacturers of these tools produce them in a wide range in terms of working sizes. But to make it easier to understand them, you need to be able to distinguish them by series:

• short series (length ranges from 20 to 131 mm, and diameter from 0.3 to 20 mm, respectively);
• elongated (length 19-205 mm, diameter 0.3-20 mm);
• long (length 56-254 mm, diameter 1-20 mm).

Marking

Its labeling, which is not so difficult to understand, will also help you choose a particular product. Depending on the working diameter, it contains the following information:

• If the instrument has a diameter of up to 2 mm, there is no marking.
• For models with a diameter of 2-3 mm, it includes information about the steel grade and cross-sectional size.
• If the diameter is more than 3 mm, then the marking includes data on the steel grade, working diameter and an imprint of the manufacturer’s logo.

This or that alphanumeric designation of the material grade indicates not only the category of the alloy, but also about the presence of additional components in it.

For example, the letter “P” means that the product is made from high-speed steel. If there is a letter “M”, then this indicates that the composition contains molybdenum, and “K” indicates the presence of cobalt. These additional substances are designed to improve the performance of the product.

Foreign manufacturers include in their labeling more information, in particular the markings in them indicate the following:

• country of origin;
• trademark;
• alloy grade;
• working diameter;
• accuracy class;
• brief recommendations on materials that can be worked with with this tool.

Features of foreign markings

So, if we talk about the last point, which indicates the presence of recommendations on what materials are best processed with one or another tool, then such markings on foreign models are deciphered as follows:

• HSS-R and HSS-G - the product is recommended for processing steel products made by simple casting or injection molding, and those made on the basis of alloy or carbon steels with a strength of up to 900 N/mm 2, things based on metal alloys ( containing copper, zinc, nickel, aluminum, etc.) billets based on malleable or gray cast iron.
• HSS-G Co 5 - recommended for drilling metals with a strength of up to 1100 N/mm 2. These include stainless, carbon, alloy, thermally enhanced and heat, acid or heat resistant types.
• HSS-G TiAN/TiN - the working part of such products is coated with titanium, aluminum and nitride. This increases their resistance to wear and corrosion, and the tools themselves can be used for processing metals with a strength of up to 1100 N/mm 2. This includes malleable and gray cast iron, copper alloys, and steel blanks made by casting.

Which metal drills are better?

After reviewing the markings and characteristics of metal drills, let's move on to popular brands that are present on the market. It is no secret that the service life and quality of work largely depend not only on the characteristics of the product, but also on the manufacturing company.

Experts advise paying attention to the following brands:

• Brands from the CIS countries have high strength and reliability, are resistant to wear and are distinguished affordable price compared to foreign analogues.
• Ruko - products can have a cross sharpening and different types spraying, they can be called best example ratio of price and quality of products.
• Bosch - this brand speaks for itself.
• Haisser - the products of this brand have their own design features, special alloys are used for its manufacture. All this allows it to be successfully used even under extreme loads.
• "Zubr" is a Russian brand that offers high-quality and reliable options at an affordable price.

Rules for sharpening

If the cutting part of the drill is dull, then it needs to be sharpened. Follow these recommendations:

• Check whether the sharpening device is working properly and prepare a container with coolant.
• When sharpening, press the tool tightly against the grinding wheel, starting processing from the back of the cutting edge.
• The processing angle depends on the material of manufacture. For steel it is 140 degrees, for copper - 100, and for copper alloys - 120 degrees, respectively.
• As a result of the work, the entire cutting surface, including the side, must be processed.

Since there are so many different drills for processing metal products on the market, sometimes making the right choice and avoiding mistakes in work can be extremely difficult. This material will allow you to choose the right tool option.