Drill steel grades - which are better? Diameters of drills for metal Drill kx what does it mean

Drill for metal: design, geometry, drill elements. How and from what drills are made. Shank types and markings. Selection, application and storage rules. The best manufacturers and tips for choosing drills for metal.

In mechanical engineering, a metal drill is the second most used tool after a cutter, and in the household it confidently shares leadership with a hacksaw and a cutting wheel. Structurally, the drill is a long cylindrical metal rod with two cutting edges at the end and spiral grooves for chip removal. The principle of cutting metal and forming a hole for all types of this tool is almost the same, so the main classification of drills for metal is based on design features (shank type, helix profile, type of cutting edge, etc.). It is rather difficult to determine all the necessary characteristics of the drill by appearance, since the marking that is engraved on the metal of the shank contains information only about the diameter of the tool, the material of manufacture and the manufacturer. Therefore, in order to choose a drill for processing hard, brittle or ductile metals and alloys, you must use the manufacturers' catalogs. Long-term and short-term storage of drills must be carried out according to certain rules, since tool and high-speed steels are prone to corrosion, and sharpened edges are easily damaged when they hit metal.

Any drill, regardless of its purpose and design features, consists of two main components: a shank and a working part. The first one serves to transfer rotation to the tool from the drive or fix it in a stationary state (on lathes). The working part consists of a number of elements that directly provide the drilling process. The geometry of the drill depends on the features of drilling for which it is intended, as well as the material of the workpiece being processed (various metals, wood, plastics, composites, ceramics).

As an example, one of the most common types of such a tool in the industry is taken: a twist drill for metal work with a conical shank (see drawing below). All drill angles shown in the figure are for general metal work. On the left is a side view, and on the right - from the side of the working end (enlarged).

Further, with explanations, all the main components and geometric parameters of such a drill are listed:

1. Shank. Serves for fixing the tool in the machine spindle or chuck. When drilling metal on lathes, it is fixedly fixed in the cone of the tailstock.
2. Working part. Forms a cylindrical hole (or recess). It consists of a cutting part, the length of which for such drills for metal is usually half their diameter, and a guide with grooves for chip removal.
3. Morse taper. For installation in spindles and tailstocks of machine tools, a tool with a conical shank is used, and for clamping into cam and collet chucks, with a cylindrical shank.
4. Foot. These features are only present on tapered shanks and are designed to knock the tool out of the spindle or arbor.
5. Neck. Provides ease of approach and retraction of the grinding tool for spiral grooving. It does not perform any work functions, so it is usually marked with a drill (minted directly on the metal).
6. Guiding part. Also called a calibrator. Leaning on the walls of a hole drilled in the metal, he directs the tool along its axis. Includes helical ribbed surfaces and flutes for chip evacuation.
7. The angle of inclination of the spiral surface. For metal processing, it is 18÷30°.
8. Chip groove. Chip removal speed depends on its width, slope and surface quality.
9. Cutting diameter. Equal to the distance between the outer edges of the cutting edges.
10. Cutting edge. This is a sharp edge between the front surface (flute) and the back surface to be sharpened.
11. The main angle at the top. The angle between the cutting edges has a significant impact on the cutting process and the strength of the drilling tool. For metal work, its standard value is 116 ÷ 118 °.
12. back surface. To reduce friction in the cutting zone, the back surface is sharpened at an angle to the cutting edge. For drilling metal, its value near the ribbon should be 8 ÷ 12 °.
13. Jumper. Structural part common to both rear surfaces.
14. Cross cutting edge. A sharp edge on the lintel that separates the rear surfaces. With proper sharpening, in its middle is the geometric center of the cutting part, which must coincide with the axis of the tool.
15. Ribbon. Two strips slightly protruding above the spiral surfaces, which calibrate the hole and reduce friction against its walls.

The general layout of other types of drills for metal is similar to this, although, depending on their purpose, they may differ in the design of the cutting part and chip grooves.

Types of drills for metal

The main classification of the drilling tool is carried out on a constructive basis, since it is directly related to the purpose of a particular type of drill for metal. In addition, within the constructive types, varieties are distinguished according to the type of material for which the tool is intended to be processed (the so-called cutting groups). There is no strict classification for them, but usually the following types are distinguished by the type of working part:

• spiral;
• feather;
• centering;
• special.

Among the special drills, the largest group is the tool for deep drilling in metal workpieces. Separate subgroups also comprise products for drilling holes of large diameters and stepped cylindrical profiles. It happens that a modern prefabricated tool has such a complex or innovative design that it is referred to several types at once.

spiral shape

The traditional widespread type of drilling tool are twist drills, in which the formation of a cylindrical hole in the metal is carried out by two symmetrical cutting edges. When this removal of the formed chips passes through the spiral grooves, the initial part of which is the front surfaces that form these edges. By their design, these products can be monolithic or prefabricated, with a replaceable head or mechanical fastening of the cutting inserts. To reduce friction and increase the speed of chip removal, the spiral part is polished and coated with wear-resistant materials.

step shape

Step drills are used to produce shallow holes with fixed step geometry. Such a tool allows you to form two or more cylindrical surfaces in one pass and is most often used in automated processing. By their design, modern step drills, as a rule, represent a monolithic block that repeats the configuration of the future hole, with rows of cutting inserts and straight flutes. The first ones drill an initial hole in the workpiece metal, and the ones following them are reaming holes. The biggest problem with this tool is chip removal during machining. Therefore, their application is limited to highly specialized areas.

Core drills

A core drill is a hollow tool with an annular arrangement of six or twelve cutting surfaces and a corresponding number of chip removal grooves. It is used for through drilling holes in metal of large diameters. During operation, the cutting edges cut only the ring around the middle of the future hole, and the central part of the metal simply falls out (or is knocked out) after passing through. This tool is referred to as a drilling tool, rather, according to an established tradition, since, according to its principle of operation, it is much closer to cutters.

Auger drills

When drilling holes in metal to depths that are multiples of 30–40 diameters, elongated drills of a special design with a spiral groove in the form of an auger are used. This solution greatly improves chip removal and allows continuous drilling of metal to the full depth of the hole without periodic withdrawal of the tool. Auger drills differ from conventional spiral drills in their large flute angles (up to 65°) and their triangular profile. In addition, they have an increased core diameter and a special sharpening of the front surface.

Spade drills

Spade drills are used to make holes in metal covered with casting scale and scale. Structurally, this is the simplest drilling tool, because it has straight grooves and a cutting part in the form of a plate. Its disadvantages are a direct consequence of the simplicity of design and low cost. In the process of drilling metal, spade drills have poor chip removal, and they tend to move away from the axis of the hole. The protruding plate reduces the strength of the entire product, which does not allow working at high feed rates, and also requires frequent regrinding. This is a highly specialized tool of increased rigidity, which is used when working with castings and forgings.

Shank types

In accordance with the early Soviet GOSTs, which are still in force, two types of shanks were provided for metal drilling tools: cylindrical and conical (Morse). In 1990, GOST 28706-90 was adopted, which duplicated the ISP 9766-89 regulation for cylindrical shanks with a flat. This type of shanks is designed for prefabricated drills for metal, in which the flat prevents them from turning in the tooling during operation. Now this solution is widely used for modular tools, and where the drill is directly fixed in the spindle, Morse taper products are still used.

Drill marking according to GOST

The rules for marking drills are regulated by GOST 2034-80. According to this document, drilling tools with a diameter of less than two millimeters are not marked. All data about them must be indicated on the packaging label. For drills with a thickness of more than two and up to three millimeters, the marking of the drill for metal contains only the diameter value and the steel grade (thus they can be distinguished from a tool up to two millimeters). For diameters over three millimeters, as part of the marking, the manufacturer must indicate its size, its trademark, metal grade and accuracy class. The grade of metal from which the tool is made can be indicated both in the form of the GOST steel designation (for example, R6M7K6), and the international abbreviation (HSS) generally accepted for high-speed steels with the addition of the designation of the main alloying metal (Co, Ni, Ti, etc.) ( see photo below). Foreign manufacturers label their products in a similar way, so you can only distinguish Russian drills from imported ones by brand.

Color coding

In their catalogs, all leading manufacturers of drilling tools use the color coding provided for by the international standard ISO 513 to designate products. In accordance with this regulatory document, all tool materials are divided into six groups, each of which is intended for processing certain types of metals, alloys and polymeric materials.

Group	Color	Machinable metals and plastics
P	Blue	Certain types of carbon, alloy and tool steels. Steel for castings. Some grades of corrosion-resistant steels.
M	Yellow	Austenitic corrosion-resistant steels. Certain types of non-magnetic and wear-resistant steels.
K	Red	Various grades of cast iron.
N	Green	Non-ferrous metals and their alloys. Thermoplastics and Duroplasts.
S	Golden	Heat-resistant alloys based on nickel, cobalt, titanium and iron.
H	Grey	Hardened steels of high hardness.

In addition, each cutting group is divided into application groups, which are indicated by a number ranging from 1 to 40. Groups with a higher index have higher strength, and those with a lower index have greater hardness and wear resistance.

Structurally, the twist drill consists of two main components: the working part and the shank. The first is made of high speed steel or hard alloys, and the second is made of carbon tool steel. The production of twist drills for metal includes the following enlarged stages:

1. Preparation of components. Cylindrical blanks for both parts are cut on bar machines, and then cleaned from burrs, surface oxides and impurities.
2. Welding. Two parts of different metal are welded by flash butt welding. After that, excess metal is removed from the welds, and the workpieces are corrected to give them an accurate cylindrical shape.
3. Turning. The blanks are centered and turned to the exact size. At the same stage, the ends are cut, the shank cone is sharpened, the end of the cone is turned under the foot (the last two operations are absent for a tool with a cylindrical shank).
4. Milling. Mill the foot (for tapered shanks), spiral flutes and flanks. After that, the workpiece is subjected to heat treatment, followed by cleaning in a sandblasting plant.
5. Grinding. Grind and polish the grooves of the spirals. After that, the shank and the working part are subjected to grinding (with finishing of the reverse cone).
6. Drill sharpening.

Cases of prefabricated drilling tools, in which the cutting part is made of hard-alloy plates with brazed or mechanical fastening, are quite complex products, since their manufacture requires complex milling and turning. Therefore, they are usually made on CNC machines or machining centers.

Table of drill sizes for metal

State standards, rules for the manufacture of twist and center drills for metal, include tables of size ranges for different designs and directions of rotation of the spiral. Each standard size corresponds to a unique digital code designation. For example, if a drill with a cylindrical shank is 3.1 mm in diameter, it has an N1 design and a right-handed spiral, then its total length should be 65 mm, the length of the working part should be 36 mm, and the code for such a product would be 2300-7517. Dimension tables for metal drills with a tapered shank include a diameter range from 5 to 80 mm, and for a tool with a cylindrical shank - from 0.25 to 20 mm. At the same time, for thin drills with a diameter of up to 1 mm, only the N1 version with a right-handed spiral is provided.

Manufacturing materials and coatings

The main materials for the manufacture of working parts of a monolithic drilling tool are high-speed steels and hard alloys. As a quick cutter, steels with tungsten or tungsten-molybdenum ligatures are most often used. The latter are also used in the variant with the addition of cobalt. Hard alloys, which are produced by powder metallurgy, are more durable, stronger and more heat-resistant than high-speed steels. They usually contain several refractory metals such as tungsten, titanium, cobalt and tantalum. Some products designed to perform several technological operations in one installation of the tool (for example, a combined drill) may include components made from different tool materials.

To improve the performance of metal drills, their surfaces are subjected to additional processing or coated with solid metal compounds. The most common processing methods that increase the strength and wear resistance of the tool are cyanidation and sulfiding. And for protective coatings, titanium carbonitride (TiCN), including alloyed with aluminum (TiAlN), is usually used.

How to choose a drill for the metal being processed

When choosing a drill for metal work, first of all, you need to familiarize yourself with the color markings of the ISO 513 standard, which all manufacturers of drilling tools adhere to. At the same time, it must be understood that such marking is not applied to the product itself, but is present only in its catalog description. You can, of course, rely on the advice of a consultant in a tool store, but this method is only suitable if you need to choose a drill bit for a drill designed to work with ordinary structural steel. If you have to drill hard or viscous metals or you need high-quality custom work, then it is better to follow the recommendations of professionals. The figure below shows an example of the use of color coding from the Mitsubishi catalog.

It must also be remembered that the parameters of the drilling process depend both on the characteristics of the drill and on the power and speed of rotation of the drive. Therefore, it is better not to use screwdriver bits with a drill, as this will most likely damage them. And the speed of rotation of a screwdriver is clearly not enough for drilling metal with conventional drill bits for a drill.

Drills used in machine tools

On drilling machines with a Morse taper spindle bore, metalworking drills are mounted directly into the spindle. And for their fixation, it has a special through groove for jamming the foot. The same drills are also used in universal machines (drilling and milling, etc.), in which the spindle bore is made for a metric cone or one of its modern varieties. Only in this case they are inserted into adapter mandrels with an appropriate cone. In general, metal drills used on machine tools do not differ from those used when drilling with hand tools. The only type of drilling tool designed for machine tool use only are drills with a through channel designed to supply coolant to the machining zone (see figure below).

Top Producers

Among Russian manufacturers of drilling tools for metal work, the products of the Volzhsky Tool Plant (VIZ), the Tomsk Tool Plant (TIZ) and the Tulamash Production Association have a good price-quality ratio. The tool of the Ukrainian Zaporozhye Tool Plant (ZIZ) belongs to the same category. The best in quality are drills from world-famous manufacturers of cutting tools, such as German Bosch, Hasser and Ruko, Swedish Sandvik, Japanese Mitsubishi, Taiwanese Winstar, etc. But their products have a rather high price and are intended mainly for professional use. In addition, metal drills under the trademarks of well-known sellers and manufacturers of power tools are massively represented on the market. Basically, this is an inexpensive tool, but many of the products are of very high quality. In this category, users most often note Zubr, Interskol, DeWalt, Hilti, Makita and Metabo.

Drill Storage Rules

At the workplaces of industrial enterprises, drills are stored in tool cabinets and sheet metal cabinets installed in the immediate vicinity of the machine, as well as on racks in special tool pantries. The drilling tool must be placed in a certain order (by types and diameters) in the appropriate compartments, cases or covers. Laying should ensure the safety of the cutting edges, as well as working and seating surfaces. Before being stored, the drilling tool is cleaned of metal dust and dirt, and if it is not used for a long time, it is lubricated with lithol or technical petroleum jelly. In order to prevent corrosion, it is forbidden to place acid-containing and other aggressive liquids near the tool storage areas. In home workshops, tools should be stored in compliance with the same rules. Only instead of bedside tables and cabinets it is much more convenient to use plastic pencil cases and special stands (see video below).

When drilling deep holes in metal, it is recommended to water the surface of the tool with a small amount of oil. I-20 is usually used in production, but not everyone has the opportunity to purchase this particular brand. And what kind of oil can be used instead of industrial oil at home? Please share your thoughts and recommendations on this issue in the comments.

Almost every head of the family has a minimum supply of necessary tools for various purposes. And one of the most common jobs is drilling. And for some, this is a regular need. But according to the universal “law”, at the right moment, what is needed is not always at hand. Then you have to go to the nearest store in search of good drills for metal, wood, etc.

Just as a warning for the future - it is not recommended to purchase ready-made whole sets of drills. Yes, they look beautiful and bewitching, but there is no guarantee that all of them will be needed. Except in rare cases, such a variety is not needed in everyday life, a few really necessary units are enough.

Before heading to the store for drills (or one), it is worth considering some points:

• The type of material with which you will have to work, not forgetting about its features and steel grade.
• To what depth should the drill be immersed, that is, whether it will be a through or penetrating procedure.
• Required hole diameter.
• What kind of tool will be used for drilling (hand or electric drill, hammer drill, screwdriver).
• The parameters of the tool used (speed, power, etc.).

However, these are general recommendations. And since the drill is selected for specific purposes, and the product range is diverse, it is worth dwelling in more detail on some important points. At the same time, along the way, we will find out what nuances can be.

Drill classification

Most manufacturers produce their products for metal in a fairly wide range of working sizes. And so that ordinary consumers do not have confusion among such a great variety, regulatory documents (GOSTs) were specially developed. Among them are GOST 886-77, GOST 10902-77, GOST 4010-77. According to them, all products are divided according to several parameters: form, purpose, performance.

But initially, all drills can be divided into two main groups: 1 - for metal; 2 - for wood and other soft materials. Drills for metal have two longitudinal grooves, with the help of which the chips are removed to the side. In addition, they are distinguished by a special sharpening angle. As for core and cone drills, they drop out of this list.

If there is a need to make a hole in the metal layer for a self-tapping screw, you should not take a drill of the same size. Usually, if the thickness of the metal is less than 0.5 mm, then there is no need for pre-drilling, otherwise it cannot be dispensed with. The table below may come in handy.

And since in the assortment of self-tapping screws you can find a large number of pointed black hardware, you should use another table. In addition, their diameter starts at 3.5 mm.

As you can see, the diameter of the drill must be selected to a smaller value than the same parameter of the self-tapping screw.

Dimensions

According to the same GOST 10902-77, there are three groups of drills depending on their diameter and length:

• Short series - the length is in the range from 20 to 131 mm, and the diameter is 0.3-20 mm.
• Extended series - longer drills: from 131 to 205 mm with the same diameter as in the group above.
• Long series - these products are even longer: 205-254 mm, the diameter here is also slightly different and ranges from 1 to 20 mm.

This division makes it much easier for buyers to choose one or another product. For the most part, this refers to the spiral, but there may be other varieties, depending on the needs of production. And as you can see, the classification does not end there. But in everyday life, different situations can also arise, and then you should pay attention to the shape of the drills.

cone products

What are the best drill bits for metal? This we will find out in the course of the text. Cone drills allow you to make holes of arbitrary shape, which can be understood by their name. The master only needs to determine the size of the required circle and accurately set the center of drilling. When working with conical products with even walls, it is necessary to constantly monitor the entire process.

With the help of such products it is easy to work with aluminum sheets, non-ferrous metals, as well as with steel structures up to 6 mm thick. But besides this, they can also be successfully used in relation to other materials: plastic, wood, plywood.

Step drills

It is easier to work with step drills - a certain step corresponds to the required diameter. In such drills, the working part is made in the form of a stepped cone. But unlike the aforementioned tools, there are stepped ring transitions on the surface.

The question of which metal drills are better worries any business master. And the answer may have already been found - due to its shape, processing can be performed at high speed. And it is worth noting that the stepped edges have a high degree of strength. Like many other metal drills, they can be used to work with drywall, plastic, concrete.

Crown shape

The crown shape of the products is used for large sizes, and they can also work with multi-layer materials. And due to their structure, such drills do not depend on the power of the tool used. The cutting force is small, which allows you to work with a conventional drill. If you need a choice, you should pay attention to the shank - it is desirable that it be powerful and durable.

Thanks to this, the possibility of slipping good metal drills in the chuck is eliminated. It should be taken into account that vibrations and overheating contribute to increased wear of the product. Therefore, it is worth minimizing these factors, and it is better to get rid of them altogether.

Spiral

These are the most common drills today, but by the way, they have always been popular and are unlikely to lose their relevance in the near future. And as for domestic use, it is usually in them that the need arises. Even every schoolchild from labor lessons knows how they are arranged - a cylindrical rod in which there are two grooves with cutting edges. In this case, they are located in relation to the axis of the cutting product at an angle of 10° to 45°.

At the same time, almost everyone has a right cut, but there are drills with left rotation for metal. They are used when it is necessary to drill out some broken fastener when it is not possible to manually unscrew it. Actually, this is their main and, perhaps, the only purpose of left-handed products.

Marking

As you might guess, any drill will plunge into the surface or workpiece in the case when its cutting part is harder in relation to the material. Therefore, marking them helps to make the right choice in relation to one or another drill for metal.

As a rule, it is located on the tool shank. And here it is worth paying attention to how it is applied - if all the characters are clearly visible, then the engraving was done in the factory. This is a sure sign to recognize a fake. Depending on the working diameter, the marking of drills for metal (elongated, short, long) may contain various data:

• On miniature drills with a diameter of less than 2 mm, no information is available at all. Which is quite understandable, it will be impossible to consider anything.
• On products with a slightly larger diameter (from 2 to 3 mm), there is already a marking - steel grade, cross-sectional size.
• A tool with a diameter of 3 mm or more contains more data - working diameter, steel grade, manufacturer's imprint.

Drills from foreign companies contain even more useful information:

• manufacturer's name;
• trade index of the company;
• brand of alloy used;
• working diameter of the product;
• accuracy class.

In addition, from the marking you can get some information about what kind of materials you can work with.

Alphanumeric designation

In the marking of any drill for metal (elongated or short), there are not only numbers, but also letters. As a result, you can get information regarding the category of the alloy used for the production of drills, as well as the presence of additional chemical elements in its composition. This allows you to significantly improve their performance.

The letter "P" indicates that strong high-speed tool steel is used for the manufacture of products. Often, a number of elements are additionally added - molybdenum, which is indicated by the letter "M", and cobalt (the letter "K"). Examples of such designations are below:

• P9 - a high degree of wear resistance and ductility, but thermal tolerance leaves much to be desired.
• P18 - this can be considered a good indicator, indicating high grindability in relation to a wide range of hardening temperatures.
• P6M5 are very good metal drills that contain molybdenum. And despite decarburization (decrease in carbon concentration), they serve for quite a long time.
• R12F3 - contains 3% vanadium, the grinding parameters are rather low. These drills are designed for medium load.
• R6M5F3 - long service life, but such drills are also recommended for working with steels in medium mode.
• R6M5K5, R9K5, R18K5F2 - the content of cobalt allows you to give products good hardness and heat resistance. They can already be used in high-load conditions.

In addition, on the drills you can find another type of marking: HSS or Din, which already applies to imported products. If you need to choose a really high-quality tool for specific conditions, you should not ignore all these parameters.

Drills of a number of foreign manufacturers have their own marking - HSS or Din. At the same time, a set of drills for metal HSS-G and HSS-R will be useful in working with cast, carbon and alloy steel with a strength parameter equal to 900 N/mm. Also, such products can be used for processing gray and malleable cast iron, graphite alloys, bronze, brass, aluminum, etc.

If it is necessary to work with stronger metals (up to 1100 N / mm), then HSS-G Co 5 products should be used for work. The HSS-TiAIN and HSS-TiN series are similar to the previous type, but there is corrosion protection.

Choice by color

All drills that are sold in many stores can be divided into 4 main groups depending on the color. Moreover, each shade indicates the presence of certain characteristics. The color scheme is as follows:

• Black - drills after production were treated with high temperature steam. Although they have a rather low cost, they have sufficient strength and reliability.
• Gray - no surface treatment of the products was carried out. As a result, drills are not of high quality and burn out quickly.
• Light Gold - These drills are made from hardened steel and have been treated to improve performance.
• Golden - these are the most durable products, in the production of which titanium is used. Moreover, among all other analogues, they are not only the most reliable, but also durable. But again, due to the peculiarities of production, including the passage of additional processing in several stages, such products, respectively, have the highest cost.

As for the choice of good metal drills, this issue should be approached from the side of practicality. Cheap black drills are suitable for single use and most household needs.

Products of the golden scale should be purchased only if it is justified by rationality - a large front of work, in which it is necessary to make several hundred holes in a metal surface or blanks.

The best choice

When choosing drills for your own needs, you need to pay attention not only to a number of characteristics, you should also consider which manufacturer they were made by. There are not so many of them, besides, most people, especially home craftsmen, are well aware of their names. The list below includes companies you can trust:

• Metabo.
• Ruko.
• Bosch.
• haisser.
• Polmart.
• Dewalt.

With regard to Metabo and Bosch metal drills, one thing is certain: they will last much longer than their competitors represented by Matrix, Stayer and other Chinese counterparts.

Drills manufactured under the Ruko trademark have a cross sharpening and a different type of coating. At the same time, the ratio between quality and cost is at an optimal level.

The Bosch brand itself is already a symbol of high quality and reliability. Each consumer who needs equipment for construction and repair should give preference to this manufacturer. And in the first place.

Products manufactured by Haisser are capable of operating under extreme load conditions. And all thanks to the design features, as well as the use of special alloys in their manufacture.

The company under the name Polmart also produces quality drills that can be used equally with both hand tools and stationary equipment.

Cobalt is present in Dewalt metal drills, which gives them a special hardness. And this is a guarantee that with their help you can drill more than a dozen holes. The sharpening of the products is done in such a way that the contact patch is very small. This avoids those cases when the drill leads to the side at the initial stage of drilling.

domestic products

Oddly enough, but it is the products of domestic production that can most often be found in many hardware stores. And here the choice is simplified by the fact that you can buy drills without much thought - you will not have to doubt the quality and reliability of the goods.

The Enkor company, which began its activity in 1992, deserves special mention. Today it is the largest production and trading company, whose activities are aimed at the production of various tools, including equipment for it.

As for the Enkor metal drills, the manufacturer presents two main series:

• HSS drills.
• Drill R6M5.

The first group includes products of a cheap price category that perfectly cope with many household needs. Just right for many home craftsmen who love to spend their working time in the country or in their garage. For an affordable price, you can purchase drills with a diameter of 0.8-1 to 13 mm. At the same time, all products are completely ground, and the sharpening angle is 118 °.

The second group is already designed for professionals in their field or more demanding consumers. For the manufacture of such equipment, a more durable material is used - high-speed high-speed steel R6M5. The surface of the products is also completely ground, and the sharpening angle is already 135 °. And thanks to the cross-shaped undercut of the jumper, preliminary punching of the metal surface or the workpiece is not required.

A set of drills for metal "Zubr" is also worthy of attention. This equipment has such necessary parameters as quality, reliability, cost, which are also harmoniously combined with each other.

Metalworking does not cause difficulties only for those who know how and with what to work. Beginners in this business have to start with the basics, for example, to find out which metal drills are best or what shape of the tip is needed for round holes.

There are not so many special tools that work without the help of a machine. Therefore, it is important to understand what drills are, how they are classified and what they are intended for.

Drills for metal: design differences and marking

The modern market offers a large selection of cutting tools for metal processing. You can purchase a ready-made universal kit or a set of metal drills.

For a one-time use, you should not pay for everything at once, but choose something specific to perform any operation that meets certain characteristics.

Tip: Considering the tool, pay attention to the markings, where many parameters are encoded. These are letters and numbers that all types of metal drills have.

According to a brief inscription, an experienced master immediately understands all the parameters:

• metal of manufacture;
• what material to work on;
• working diameter of the drill;
• accuracy class;
• country of origin (logo).

Spiral gimlets of minimum diameter are not marked. But the novice home master will not be able to understand the rest of the designations. For example, the R6M5K5 marking indicates a composition with a certain percentage of tungsten, molybdenum and cobalt - this is the highest quality drill.

But even with 15% cobalt, it is also a high-quality tool, in the designation P9K15 it shows that this is a high-speed steel drill.

Imported products with alloy steel are marked with HSS:

• HSS-E VAP (for working with stainless steel);
• HSS-E with the addition of cobalt (for working on metal with increased viscosity);
• HSS-Tin with titanium (for increased hardness of the cutter);
• HSS-4241 drills aluminum products;
• HSS-R tool for maximum strength.

Attention: Look for the markings on the metal drill shank as shown in the photo.

What brand of drill is best?

In the stocks of home craftsmen, tools and equipment from Soviet times have been preserved to this day. It cannot be said that these were bad drills, especially victorious ones, but how to sharpen a drill for metal without equipment?

It is easier to buy a new cutting tool from foreign and domestic manufacturers:

• Bosch - any product of exceptional quality.
• Ruko - Look for the best hard facing cross drills for reliability.
• Haisser - their titanium nitride coated drills withstand extreme loads (processing steel, copper, bronze, cermets, etc.).
• “Zubr is a well-established domestic brand, the best value for money, offers reliable cutters for metal, in particular with cobalt.

Important: A hole in a thin product made of a pliable alloy will take any drill. For "specialists" working on metal, it is not profitable to buy cheap gimlets of dubious quality and spend time sharpening them.

As a rule, drills are specialized in metal and wood, but they can also work in other materials, including concrete, ceramics and polymers.

Drills, their varieties and characteristics

For metalworking, drills are used that structurally have much in common:

• cutter;
• working surface (provides advancement with chip removal);
• shank (fixed in the chuck).

Main classification:

• stepped or cone (conical) drills;
• feather (flat);
• crowned;
• spiral.

You can find other types of drills for metal in the catalogs, but these are only discrepancies in the names. For example, annular cutters are the same core drills. On the end part you can see the teeth with diamond coating. Standard core drills select the contour of the hole.

Step or conical drills - for holes of the desired diameter in thin metal plates. The advantage is that there are several diameters in one tip at once, but they are practically not used in everyday life.

Material classification

The cutting tool is most often produced from steel, but when metalworking with hard alloys, the temperature rises. If the temperature threshold is violated, the drill becomes dull - cutters with plates of sufficient hardness, for example, alloyed with cobalt, are needed.

Titanium drills are a good alternative to cobalt drills in terms of hardness and reliability. Technological use guarantees long-term work with factory sharpening.

Carbide carbide tool shows increased wear resistance. Although these drills do not require regrinding, this professional tool is used in thick metal. For these purposes, powerful drills operating at low speeds are used - the drills are included.

From intensive use, the tool loses its properties, but this does not apply to drills of a bright golden hue.

By the way, by the color of the drill, you can judge its performance:

• Black surfaces - from hot steam to increase wear resistance to extend the life of the application.
• Gray - drills for domestic use, after working with hard metal, they become unusable.
• Golden - high-speed drills that have undergone a special hardening procedure, they inspire confidence even in experienced craftsmen.
• Bright golden surfaces are the best titanium tools for metalworking, but they are quite expensive.

The size of the drill bits for metal does not affect the quality, but a wide range of gimlets makes it possible to choose the right tool for any metal work. The size scale is regulated by GOST standards. The working length of the incisors ranges from 20 mm to 131 mm, in diameter their parameters are 0.3 mm - 20 mm.

Photo drills for metal

Drill- a very popular tool not only in various fields of activity, but also in everyday life, in daily use. A very wide range of drills from different manufacturers sometimes just stuns the average buyer. Let's find out how to choose a drill for metal and which manufacturer's drills should be preferred.

Drills for metal

Metal drills are used to cut holes in non-alloyed and alloyed steel, cast iron, non-ferrous metal, etc. This type of drill has a helical shape, hence the appropriate name, twist drills. Twist drills have two longitudinal flutes that evacuate chips while drilling. There are several types of twist drill shank - conical, hex and cylindrical. The conical ones are inserted directly into the machine, the cylindrical ones are inserted into a special cartridge.

If you are interested in the question: “Which metal drills are better?” Pay attention to the color when choosing a drill, it will say a lot about the quality.

Choosing a quality drill by color

If the drill is black, it means that superheated steam was used in the finishing. Such a drill has increased wear resistance.

If stress relief was used during finishing, the drill will have a slight golden hue.

High-quality metal drills have a bright golden hue - a layer of titanium nitride is applied to the drill. These are very high quality tools, have high strength and reduced friction. A little more expensive than the rest, but also superior in quality to the rest.

The regular gray drill (cheapest) has no processing. The minimum price and the same service life, and nothing more.

Look at the photo of metal drills to finally remember the types of colors and their inherent characteristics.

Drill marking for metal

The marking depends on the diameter. Drills up to 2mm are not marked, on drills up to 3mm, the steel grade and diameter are indicated, thicker drills may carry information about the manufacturer and accuracy class.

Drill marking begins with the letter P - high speed steel. In the form of a numerical value, the content of various substances in the alloy is also indicated. For example, K6 is part of cobalt, M3 is molybdenum content. On imported drills, the marking is in the form of HSS or Din values.

Having learned the characteristics and types of drills, you now know exactly how to choose a drill for metal. We will only give examples of high-quality drills that are widely used by professionals.

RUKO twist drills for metal TL 3000 (HSS-G, HSS-E, HSS-G TiN, HSS-G TiAlN)

Drills for metal ruko model range TL 3000 are known to consumers as high-quality material at an affordable price. Drill diameter - from 3mm (have a cross sharpening according to DIN 1412 C). The drills have a sharpening angle of 130°. Depending on the specific model, they are coated with titanium nitride, titanium aluminum nitride, etc.

Multi-purpose drills, great for large drilling depths. Best suited for materials that form long and medium chips.

HSS-G drills perfectly drill carbon and alloy steels, cast iron, copper and aluminum alloy.

HSS-E drills stainless and acid-resistant steel, as well as copper and aluminum alloys in addition to carbon and alloy steel.

HSS-G TiN and HSS-G TiAlN are suitable for all of the above materials as well as titanium alloy.

Drills for metal BOSCH HSS-CO

BOSCH drills of the HSS-CO model range are made of high speed steel according to all standards. The drills have an oxide coating that quickly removes chips during drilling. The standard 135° chisel-shaped edge with mesh grinding is suitable for almost all types of work.

Alloying with cobalt improves the strength and heat resistance of the drill. The tensile strength is 1000N/mm2, which allows it to work with most types of steel and alloys, as well as cope with heavy production tasks.

Accuracy class h8 provides the necessary exposure of the outer diameter.

HAISSER metal drills with titanium coating

One of the most powerful drills that are used under extreme load in domestic and industrial environments. Drills have cross-shaped sharpening. Titanium coating provides maximum cooling, which allows you to work in the most difficult conditions. The main application of the drill is found in the field of industrial and complex work. Angle 135 with mesh polishing. Titanium nitride coating gives minimal friction and reduced cold welding. Due to their high wear resistance, the drills have a uniquely long service life.

Drill for metal ZUBR "Cobalt"

Drill for metal ZUBR is made of R6M5K5 high-speed steel. Has a cylindrical shank. According to the strength class, it belongs to category A1. The use of cobalt (5%) in manufacturing gives this drill extra strength and wear resistance.

Cobalt drills are used for drilling non-ferrous metals, stainless steel, hard-to-machine tough steel, etc. Drills are made in accordance with GOST 10902-77. The price of the ZUBR "Cobalt" drills is quite consistent with the quality of the product, so many buyers make a choice in favor of this product.