What steel are drills made from?

What parameters need to be taken into account when choosing metal drills?

When working with power tools at home, attention must be paid to the equipment. If you are using a drill and need to work with metal parts, you will need a metal drill. You need to be able to choose high-quality and suitable equipment so as not to pay twice.

Design and functional features

Metal drills are used not only for drilling metal parts and workpieces. They are used to create holes in plastic, wood and ceramics. The design of such drills consists of three parts:

1. Working part. It has a certain sharpening, thanks to which holes are created.
2. Surface for removing chips when drilling.
3. The shank with which the cutting tool is secured in the chuck of a drill, hammer drill or screwdriver.

When using a metal drill, the chuck must be positioned strictly perpendicular to the workpiece being processed. If there is a slight deviation, the risk of the tool splitting or jamming in the part increases.

Classification

There are various types of metal drills available in stores. They vary in material, size, and design. To separate them, a special classification is used. A home handyman needs to know what types of drills there are and for what purposes they are used.

Spiral

Spiral tools for creating holes are the most popular among other accessories for drills, hammer drills and screwdrivers. They are a cylindrical rod made of metal, the smaller part of which is occupied by the shank, and the larger part is occupied by a spiral sharpening for drilling. The grooves cut into the cylinder are designed so that during operation the chips come out of the hole outward. There are three types of spiral equipment design:

1. A classic metal drill in the shape of a cylinder with sharpening along the entire diameter. Used in production and at home.
2. Left-handed equipment. Designed for drilling broken fasteners out of holes.
3. High precision drills. With their help, holes are created with minimal error.

This type of metal drill is the most numerous and widespread.

Conical stepped

They are special gimlets that have a conical shape and stepped elements on the working part. They are used for drilling thin sheet metal and finishing finished holes. If the color of the drills is golden, then they are suitable for drilling materials with high density.

Core annular cutters

They are a hollow crown. Along the edge of the circle there are teeth of the same size, which are needed to create large-diameter holes in thin sheet metal. The chips that appear during drilling exit through the cavity of the tube.

Feathers

They are special equipment for creating smooth cylindrical holes. The plates, which are “feathers,” are attached to a metal rod. The created recess will not have any distortion or defects on the inside.

Features of choice

To choose the best metal drill bit, you need to pay attention to a number of factors. Each of them is worth talking about separately.

Which material is better

Many craftsmen do not know what material is used to make drills. To drill workpieces, the material must be harder than the product itself.

The main material for the manufacture of equipment in drilling equipment is high-speed steel. Marked on imported equipment with the letters P and HSS.

Additionally, other letters are indicated on the equipment. They indicate third-party metals in the composition. High-quality equipment is marked with the letter “K”. It indicates the cobalt content of the base metal. The higher the percentage of this material, the stronger the equipment.

Choose by color

In hardware stores you can find cutting tools of different colors. However, not many people think about the fact that this feature affects the characteristics of the equipment. For example, if the color of the drill is black, it means superheated steam was used in its manufacture. The advantage of this processing method is its increased wear resistance.

If the cutting tool has a golden hue, then such equipment has an increased strength index. When processing such equipment, titanium nitride is used. A dull golden hue indicates that the cutting tool has virtually no internal tension. The color of poor quality equipment is grey.

Marking

To understand which equipment is best to choose, you need to understand the markings of metal drills. Tools from foreign manufacturers have the following designations:

1. HSS G Co. Designed to work with metal products with a strength of 1100 N/mm2. It can be stainless steel, alloy or carbon steel.
2. HSS R or HSS G. The most common drills, which are designed to work with materials with a strength of no more than 900 N/mm2.
3. HSS-G TiAN/TiN. Wear-resistant equipment, which is coated with a layer of titanium nitride. Such products are resistant to corrosion processes.

Additionally, the manufacturer, drill size, and accuracy class are indicated.

Sharpening angle

When determining the sharpening angle, you need to use special tables that can be found on the Internet. The optimal value for twist drills is 116–118°. When the cutting part is dull and the drill is expensive, you can send it to a specialized workshop for resharpening.

Size

The drill diameter is manufactured according to state standards. This parameter is described in GOST 885–77. There are special tables that show the relationship between sizes.

The diameter starts from 1 mm and ends at 16 for twist drills. The length starts from 56 mm and goes up to 205 mm. There are special extended drills. The length of the working part can reach 128 mm.

The characteristics of drills for metal and its size are indicated on the shank.
What are the best drill bits for metal?

The best manufacturers

One of the main questions that arises when choosing a product in a hardware store is which manufacturer of metal drills is better. Foreign and domestic companies manufacture both power tools and accessories for them. Popular drill manufacturers:

1. BOSH. A world-famous company manufacturing household appliances, various tools and equipment. BOSH drills have a sharpening angle of 130 degrees and are universal.
2. Bison Cutting tools from a Russian manufacturer. Cobalt is used in their production.
3. Equipment that is used under extreme loads.
4. According to reviews from craftsmen, the cutting tools of this manufacturer have the best price-quality ratio. A special feature of this equipment is cross sharpening.

Among the well-known tool manufacturers is Makita.
There are both single cutting tools and a large set on sale. 5 main characteristics of quality drills. 5 key features of quality drills

Source: https://metalloy.ru/obrabotka/sverlenie/sverla-po-metallu

What kind of steel are metal drills made of - Metalworker's Guide

For drilling metals, screw or, as they are more often called, twist drills are used. Although almost identical in design, these tools may differ in material, type of additional processing, and sharpening features. There are many varieties of drill bits optimized for different metals, drilling depths and other working conditions.

What are drills made of?

High-speed steel is used to make metal drills. This is a group of highly alloyed alloys, which, in addition to iron and carbon, include tungsten, molybdenum, cobalt, vanadium and other elements.

High-speed steel differs from ordinary tool steel in that a drill made from it remains operational when heated. Tool steel at normal temperatures is not inferior in hardness to high-speed steel, but when heated above 200°C, tempering occurs and it becomes soft. High-speed steel retains hardness up to 500-600°C, and some grades – up to 1000°C.

Tungsten is the main component that increases the “red resistance of steel” (the ability to maintain hardness when heated). However, due to limited reserves of tungsten, it was necessary to abandon steel with a high tungsten content and switch to molybdenum alloys. When the tungsten content is within 6%, the required qualities of drills are ensured by the addition of molybdenum, cobalt and other elements. Tools made from P18 steel are no longer produced, and even P9 is rare.

In foreign classifications, high-speed alloys are designated by the abbreviation HSS (High Speed ​​Steel). There are several varieties of them, and some of them are similar to the alloys specified in GOST. High-speed steel grades are designated by the letter “M” followed by a number. Let's compare several of the most commonly used brands.

M1

Steel with low tungsten content and high molybdenum content (1.5 and 8%, respectively). It is not highly durable and is used for the manufacture of general purpose drills.

M2

The alloy contains 6% tungsten and 5% molybdenum, which gives drills made from it high hardness. The Russian analogue is R6M5. Drills made from this steel have good wear resistance and red resistance.

M7

Drills made of this steel are used for deep drilling and high-force work. Its composition has a reduced tungsten content (1.75%), but an increased amount of molybdenum (8.75%) and vanadium (2%). The Russian analogue is R2M9.

M35

The Russian analogue of this alloy is R6M5K5. This steel differs from M2 (R6M5) in its higher “red resistance” due to the addition of 5% cobalt. The alloy also contains silicon, magnesium and nickel. Drills made of M35 steel can withstand high heat and provide high performance.

M42

This alloy contains a little tungsten, but a high content of molybdenum and cobalt. Drills made from it have high red resistance and hold an edge well. Work well at high cutting speeds and on tough materials. The Russian analogue is R2M10K8 steel.

Features of drills and their markings

The foreign marking system for drills reflects some of the features of their manufacture and the most important components of steel.

HSS-R

Drills of this type are made by screw rolling. They use relatively soft, deformable steel. After rolling, the tool is hardened. The letter “R” may be missing from the marking.

HSS-G

The drills are made by grinding CBN (cubic boron nitride). This is the most common type of tool for a wide range of tasks. The drills have high wear resistance and minimal radial runout.

HSS-PM

Drills made using powder metallurgy technology. Used for processing hard metals.

HSS-E (HSS-Co)

Drills made from alloys with high cobalt content. A number may be added to the marking indicating the percentage of cobalt rounded to the nearest whole number. For example, HSS-Co5 or HSS-Co8, which corresponds to M35 or M42 alloys.

HSS-TiN or HSS-TiAN

Drills coated with titanium nitride. The letter “A” in the second option means aluminum alloying. Titanium nitride coating gives the tool a golden color and increases its wear resistance several times.

HSS-E-VAP

Drills of this group are covered with a film of oxides, which is created by steam oxidation - treatment with superheated steam in a special environment. The coating is black in color, reduces the adhesion of chips to cutting edges, and increases surface wettability with coolant. HSS-E-VAP drills are effective for drilling stainless steel and other tough alloys.

The hardness of drills made of high-speed steels according to GOST 2034-80 should be in the range of 63-66 HRC.

Cutting part

Cutting when drilling is carried out by two edges, which are formed by the intersection of the front surfaces of the helical grooves and the conical head of the drill. Strictly speaking, the cutting part is not completely conical: the back surface of the blade decreases, moving away from the theoretical cone at a slight angle.

The main sharpening parameter is the tip angle. For most applications it is around 118o. For cast iron or hard bronze it can be reduced to 116o. For brass, soft bronze, aluminum, angles of 120°, 130°, 140° are used.

For drilling soft sheet metal, a special sharpening is used with curved cutting edges, a protruding pointed center and slightly protruding edge cutters. At the beginning of drilling, the drill is immediately clearly centered, then a contour is outlined, and after that the extraction of metal begins over the entire area of ​​the hole. As a result, beating at the inlet and biting of the edges at the outlet are eliminated.

For drilling steel and cast iron, double-sharpened drills are used. In addition to the apex angle of 116 - 118°, the edges are ground at the periphery, to a width of 0.2 diameters, at an angle of 70 - 75°. There are other forms of sharpening for specific applications.

Drilling accuracy

Factors affecting drilling accuracy are divided into two groups: equipment-dependent and tool-dependent. Drills are divided into three accuracy classes: A1, B1 and B. The accuracy class is determined by the maximum permissible values:

• asymmetry of the core and driver of the drill;
• radial runout;
• tolerance for straightness of cutting edges.

The accuracy class must correspond to the required quality of hole accuracy and equipment capabilities. Drills of class A1 are used for holes from 10 to 13 accuracy grades. Drills of classes B1 and B – up to 14 and up to 15 accuracy grades, respectively.

Types of shanks

The tail part of the drill, intended for mounting in a machine or hand tool, can have different shapes.

• Cylindrical shank. This is the most common form of shank and is suitable for being held in the chuck of a drill, drill or lathe.
• Conical (Morse taper). Drills with a conical shank are used on industrial equipment. They require a corresponding taper on the spindle. They are distinguished by reliable fixation, precise centering and quick tool replacement.
• Hexagonal. This shank is suitable for installation in a three-jaw chuck and is characterized by reliable transmission of high torque. Eliminates slipping of the drill in the chuck. In addition, the hexagonal shape is convenient for installing a drill bit into a screwdriver adapter. In this case, the drill does not need to be clamped, but its exact position during operation is not ensured.

Popular sets and specially shaped drills

The most commonly used drills are with a diameter of 2 to 10 mm. They are used in metalworking workshops, service stations, and households. The popularity of these diameters is also indicated by the fact that most lightweight drilling equipment has chucks adapted to this size range.

For general use, a set of drill bits with a diameter pitch of 0.5 mm is suitable. In most cases, such a set will cover the basic drilling needs. For a specific application, diameters can be selected in increments of 0.1 mm. More precise hole sizes can be achieved through additional processing.

There are special cases for which it is convenient to use special drills:

• step drill for sheet materials;
• annular drill or centrifuge for shallow through drilling of large diameter holes;
• a combination drill-tap that can be used to drill a hole and tap a thread in one pass.

Choosing the right tool for the intended application will greatly simplify the work and help achieve the desired quality.

Source: https://ssk2121.com/iz-kakoy-stali-delayut-sverla-po-metallu/

Drills for metal. Which ones are better?

A universal and important tool, without which no repair can be done, regardless of the complexity of the work performed, is a drill. Today, the building materials market offers a wide selection of different types of drills.

All drills differ not only in length and diameter, but also in the material for which they are intended for drilling (wood, metal, concrete, ceramic tiles, brick, glass).

Before drilling a particular material, it is necessary to select the appropriate drill size. Its type is selected depending on the work performed.

Metal drill

Versatility is a distinctive feature of a metal drill. This tool is indispensable when working with metals of varying strengths. With its help, it is easy to drill a hole in cast iron products, non-ferrous metals, cermets, alloyed and non-alloyed steels.

Twist drills for metal are incredibly popular today. This is a cylindrical rod in which two helical grooves forming the cutting edges are made. In relation to the axis of the rod, the grooves are located at an angle of 10-45°.

When purchasing, experts recommend paying attention to the material from which the metal drill is made. The most high-performance and high-quality cutting tools are made of alloy and high-speed steel. Alloy steel can be 9XC, high-speed steel can be P6M5. Tools made from such steels allow you to achieve a high performance during the drilling process, while being high-strength, durable and reliable.

Marking and color of metal drills

Probably, each of us has thought about what drills are made of, what does the marking stamped on the tool mean? How do you drill something like yourself using metal? This is because the product is made from high-quality and high-strength steel, and not from raw material, which penetrates the market from dishonest manufacturers.

What does the drill marking mean?

What does the marking on the drill mean? The marking of a metal drill has an alphanumeric designation: first comes the letter of the main element, followed by a number indicating its percentage in the material from which the drill is made. Other elements may also be indicated after the first two characters.

The letter P stands for tungsten, K for cobalt, F for vanadium, M for molybdenum. Chromium is usually not indicated in the labeling, since it is always present in the source material (about 4%). Carbon is also not specified.

For example, the marking of a drill R7M6K6 indicates that it is made of high-speed steel with a mass fraction of tungsten content of 7%, molybdenum - 6%, cobalt - 6%.

Domestic manufacturers do not put any information on drills for metal with a diameter of less than 2 mm. The diameter and steel grade are applied to a tool with a diameter of 2–3 mm. For all other drills, in addition to the information mentioned, the trademark is stamped, and in rare cases, the accuracy class of the drill.

If holes are drilled in metal for threads, a drill of a certain diameter is selected for each. For threads M4, M5, M6, M8, M10, M12, the drill diameter is 3.3, respectively; 4.2; 5.0; 6.7; 8.4; 10.2 mm.

Large holes in metal must be made in several stages, that is, first you should use a thin drill, then increase the diameter to the desired size.

For example, in order to drill a hole with a diameter of 10 mm, it is better to drill it in two steps with 5 and 10 mm drills.

What does the drill color mean?

All drills are produced in the following colors: bright gold, black gold, gray and black.

The bright golden color indicates that titanium nitride was used in the processing of the tool. The drill coated with titanium nitride has increased strength. During the drilling process, less friction is created between surfaces.

The black golden hue indicates that tempering was applied to the raw material in order to relieve internal stress.

Gray color indicates that no final processing was carried out to protect and strengthen the material. This means that the product is of low quality and will not last long.

The black color means that the tool has been treated with superheated steam, which has increased its wear resistance.

Cobalt metal drills P9 from the Polmart brand

Drills made of high-speed steel P9 standard DIN 338 are designed for drilling high-strength metals. These drills can work with both stationary and hand drills.

The red resistance of the described drill for metal increases due to the high content of cobalt and other alloying elements in the composition of the tool.

These cobalt drills are widely used for making holes in stainless, acid-resistant, refractory and high-alloy steels, the density of which reaches 1000 N/mm.

Metal drills from the Bosch brand

Metal drill bits from the Bosch HSS-CO product line are manufactured according to all standards from high-speed steel. Thanks to these drills, chips are removed very quickly during the drilling process due to the oxide coating of the metal drill. The drill has a chisel-shaped sharpening angle of 135° with mesh grinding and is used for drilling almost all steels.

Thermal resistance is improved by alloying the drill with cobalt, while the tensile strength is 1000 N/mm. This means that such a drill can be used for drilling almost all alloys and steels and at the same time perform production tasks of varying complexity. The required holding of the outer diameter of the drill is ensured by accuracy class h8.

Titanium coated metal drills from Haisser

These drills are sharpened crosswise and are one of the most powerful tools used for drilling in everyday life and industry under the highest loads.

Titanium coated metal drills can handle harsh conditions while maintaining maximum cooling of the titanium coating. These drills are mainly used in industry and during complex technological work.

The drill has a sharpening angle with mesh grinding equal to 135°. High wear resistance and practicality contribute to increased service life.

Such metal drills with titanium coating are used for alloyed and non-alloyed steels, non-ferrous metals, plexiglass, metal-ceramics.

Source: https://proinstrumentinfo.ru/svyorla-po-metallu-kakie-luchshe/

What do the symbols on the drills say?

22.06.2016

A drill is a cutting tool for making blind or through holes in a solid body of material, drilling out existing holes or recesses, as well as performing other types of work. The drill acts on the material only in the axial direction! (unlike cutters that can also work with longitudinal feed).

Structurally, the drill consists of a front cutting cone (with sharp working edges), outlet spiral grooves and a shank for mounting a drilling tool - a drill, a machine tool, a hammer drill - in a chuck. Depending on the purpose, all three elements of the drill can have different shapes and designs. To an experienced craftsman, they can tell no less about the purpose and “character” of the drill than the brand markings!

Drills by type

Depending on the “reference point”, all drills can be divided into several large groups:

• by type of tool material (high-speed steel, pobedite, hardened, with a protective coating, etc.);
• for metal work;
• for wood (characterized by the presence of a thin, sharp tip for ease of initial cutting into the material);
• for fragile but hard materials (concrete, brick, etc.) - recognizable by a characteristic cutting cone with a pair of “petals” having hard surfacing;
• for drilling with shock loading - they are distinguished by protrusions and grooves on the cylindrical shank for mounting in a hammer drill chuck.

Thus, even before looking at the markings of the drill, you can accurately determine the type and purpose of the tool by external signs. And only then move on to a detailed consideration of its characteristics.

Drill marking

Very thin drills usually do not have any markings (there is simply nowhere to engrave them!). On the shanks of drills with a diameter of 3 mm or more, an alphanumeric code is applied, indicating:

• grade of material - the most common high-speed steel is designated by the letter P. Tungsten-free high-speed steels (grades EK-41, EK-42) and hard alloys (VK6, VK8, T15K6, T5K10) are also used;
• percentage of tungsten in the alloy (for example P6 - high-speed steel with 6% tungsten);
• types of alloying elements (letters: M denotes molybdenum, F – vanadium, K – cobalt, A – nitrogen, Ш – electroslag remelting);
• mass fractions of other alloying elements (also in numbers);
• Finally, the diameter symbol (may be missing) and the number next to it indicate the working size of the drill.

For example: the marking on the drill “R6M5K5 10.6” is a tool high-speed steel with 6% tungsten in the alloy, plus alloying additives of molybdenum (5%) and cobalt (5%), tool diameter 10.6 mm.

It should be noted that the larger the drill diameter, the more detailed the markings on it (may include accuracy class, manufacturer’s name, etc.).

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 at medium cutting speed, used for carbon and alloy tool steels.
6. R9K5,
7. R6M5K5,
8. 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.

Foreign markings (DIN and HSS) are deciphered a little differently - although they mean basically the same thing.

• HSS (High Speed ​​Steel) – general marking of a group of high-speed steels;
• the following letters indicate the “specialization” of the drill: R (or without a letter designation) – drills with the lowest resistance, G – for working on carbon and alloy steels, cast iron and non-ferrous metals, E – for acid-resistant stainless steels, HSS-G TiN and HSS -G TiAlN – for processing titanium. Of course, “backward compatibility” is also true - a drill for titanium is perfect for processing both carbon and stainless steels;
• If desired, you can find out the detailed composition of the drill material using a special table.

Table of correspondence between the general chemical composition of HSS steels and their domestic analogues.

Type Domestic analogue Chemical composition, % C (carbon) Mn (manganese) Si (silicon) Cr (chromium) V (vanadium) W (tungsten) Mo (molybdenum) Co (cobalt) Ni (nickel) Tungsten HSS steels High alloy HSS steels

T1	P18	0,75	—	—	4,00	1,00	18,00	—	—	—
T2	R18F2	0,80	—	—	4,00	2,00	18,00	—	—	—
T4	R18K5F2	0,75	—	—	4,00	1,00	18,00	—	5,00	—
T5	0,80	—	—	4,00	2,00	18,00	—	8,00	—
T6	0,80	—	—	4,50	1,50	20,00	—	12	—
T8	0,75	—	—	4,00	2,00	14,00	—	5,00	—
T15	R12F5K5	1,50	—	—	4,00	5,00	12,00	—	5,00	—
M41	R6M3K5F2	1,10	—	—	4,25	2,00	6,75	3,75	5,00	—
M42	1,10	—	—	3,75	1,15	1,50	9,50	8,00	—
M43	1,20	—	—	3,75	1,60	2,75	8,00	8,25	—
M44	1,15	—	—	4,25	2,00	5,25	6,25	12,00	—
M46	1,25	—	—	4,00	3,20	2,00	8,25	8,25	—
M47	R2AM9K5	1,10	—	—	3,75	1,25	1,50	9,50	5,00	—
M48	1,42-1,52	0,15-0,40	0,15-0,40	3,50-4,00	2,75-3,25	9,50-10,5	0,15-0,40	8,00-10,0	up to 0.30
M50	0,78-0,88	0,15-0,45	0,20-0,60	3,75-4,50	0,80-1,25	up to 0.10	3,90-4,75	—	up to 0.30
M52	0,85-0,95	0,15-0,45	0,20-0,60	3,50-4,30	1,65-2,25	0,75-1,50	4,00-4,90	—	up to 0.30
M62	1,25-1,35	0,15-0,40	0,15-0,40	3,50-4,00	1,80-2,00	5,75-6,50	10,0-11,0	—	up to 0.30

For example, drills marked M1 are more flexible and less susceptible to shock, and are suitable for general work. M2 drills are already used for high-performance machine work, due to the high degree of red resistance and preservation of the cutting edge. The M7 marking indicates flexibility and increased drill life, which is important when drilling hard sheet metal. Drills are made from M42 steel for work on tough and complex materials, and drills are made from M50 steel for portable equipment, where tool breakage due to bending is undesirable.

HSS-E drills are analogues of the domestic universal P6M5. They are suitable for working on both low-carbon steels and cast iron, as well as hard alloy and stainless steels (including acid-resistant). And the HSS-Co tool (with the addition of cobalt to the alloy) is similar to the Russian R6M5K5 drill (also containing 5% cobalt in the high-speed alloy).

HSS-G TiN is the most durable drill for working with durable titanium products. Its analogue is the domestic tool R6T5 (the last letter and number indicate a 5% titanium content, which gives high-speed steel special strength). The surface hardness of a drill with a titanium-aluminum-nitride coating (HSS-G TiAlN) is already 3000 HV, and the heat resistance is 900°C.

Finally, drills for stainless steel are marked HSS-E VAP (V2A or V4A).

Drill bits for rotary hammers

Hammer drills are often called “drills.” They have a number of characteristic differences:

• firstly, almost only fragile but very hard materials (concrete, brick, natural stone, etc.) are processed with impact loading. For this purpose, the drills have a special, reinforced design and super-hard surfacing on the cutting edges (the cutting tip with petal edges of the drills is similar in design to that of concrete drills).
• and secondly, the drills are installed in special drilling machines - rotary hammers. Their cartridges perform not only rotational, but also axial movement. This achieves the impact of the tool on the material - along with a rotational “biting” into it. Such mechanics require strong fastening of the tool in the hammer drill chuck - for this purpose, drills have a shank with longitudinal projections and grooves (unlike conventional drills with absolutely smooth cylindrical shanks). This drill fastening system is called SDS.

In accordance with this, the markings on drills are somewhat different from those for conventional drills:

• the first is the letter designation of the drill fastening system (shank design) - SDS-max or SDS-plus;
• then two numbers indicate the diameter and length of the drill (in millimeters).

For example, the “SDS-max 16*670” drill has a diameter of 16 mm and a working part length of 670 mm.

It should be noted that the diameter of the drill is always equal to an even number. Accordingly, the size range of tools will look like Ø4 mm, Ø6 mm, Ø8 mm, etc.

And back to the appearance!

At the beginning of the article, we talked about the appearance of the drill - to an experienced eye, its structural shape will immediately allow you to determine its purpose. Equally valuable information can be gleaned by assessing the color of a drill or auger:

• regular gray indicates bare, uncoated tool steel. Such a tool may be of high quality, but it is susceptible to corrosion and rapid wear (since it does not have additional heat treatment that strengthens the steel);
• A “bold” black tint indicates that the material has been treated with steam. This increases the durability of the tool, increasing its service life;
• a yellow-golden color means that the drill material was subjected to hardening (significantly increasing the strength of the tool) and then tempering (heat treatment to relieve internal stresses after hardening). Such drills have good durability, but due to the tendency of hardened steel to develop brittle cracks, the “golden” tool is sensitive to overheating and temperature changes. Therefore, during work, it is necessary to periodically cool the tool, adhering to the manufacturer’s recommendations (this is especially true for drills for rotary hammers). And under no circumstances should drills be cooled with liquid!
• bright golden color - the surface of such a drill is treated with titanium nitride. This coating reduces contact friction in the cutting area while simultaneously strengthening the metal of the tool.

It is “golden” drills and augers that are considered the “elite” among quality tools. But the price of such drills is naturally higher.

The materials were prepared by specialists from the Triv-Komplekt company.
When copying texts and other materials from the site, it is mandatory to provide a link to the site www.traiv-komplekt.ru!

Source: https://traiv-komplekt.ru/articles/chto-govoryat-oboznacheniya-na-sverlah/

What are the best metal drills? Making the right choice

The density of the metal is so high that special tools and mechanisms must be used to process it. In order to make a hole in this material, drills and drilling machines are used, in which drills are the main cutting element.

Which metal drills are better? It is not easy to determine, because there are no universal products that would be suitable for processing all types of metal products. An experienced craftsman will be able to “by eye” determine the type of metal and quickly select the appropriate cutting tool for processing.

A beginner in this business needs to start with the basics. First, study the classification of drills and their scope of application, because the best models are products that are ideal for processing a specific type of metal.

What kind of drills there are, how to choose a suitable product for the job based on markings and appearance, find out in the article.

Types of drills for metal

To choose the best models, you need to understand the types of drills.

Spiral

Classic, cylindrical drills that are most often used for drilling metals. Typically, spiral products are made of HSS steel.

The material is a high-quality cutting type of steel, so the gimlets made from it are highly durable and durable.

Conical (stepped)

The cutting surface has the shape of a cone, which is why this type of drill got its name. Conical drills are used to make holes in thin metal, as well as to correct defects from other cutting tools.

What are the best step drills to choose? Depends on the type of metal being processed. If the density of the workpiece is too high, then it is better to purchase more expensive, golden-colored products.

In everyday life, this type of drill is rarely used. If you need to frequently drill thin metal sheets or process soft materials, then despite the relatively high cost, it should be purchased for your home workshop.

Core cutters (annular cutters)

The cutting tool is a cylinder with a cutting edge, which is used to cut metal.

The energy consumption for making a hole in this way is several times lower, due to the small contact area of ​​the tool with the surface being processed.

The advantage of using this type of drill over others is the production of large diameter holes. In this case, it is possible to obtain better quality edges than when working with spiral models.

Feathers

A special type of flat gimlet with replaceable working edges is used for drilling metal. Such products allow you to make high-quality, perfectly straight holes.

The absence of distortion during the drilling process and the ability to make a large-diameter hole in various metal structures allows many craftsmen to abandon the use of spiral products.

The low cost of feather drills allows in many cases of metal processing to call them the best for drilling holes.

These are the main types of drills used for making holes in metal structures.

Classification of drills by material of manufacture

Which metal drills are the best for drilling particularly strong alloys is quite simple to answer:

1. To process such material, you should choose products that have a plate of increased hardness on the cutting edge. Such gimlets are the best for processing hard alloys.
2. The price of such products is low due to the fact that the main body of the cutting tool is made of ordinary tool steel.

Drills made of metal alloyed with cobalt have good characteristics.

They can withstand increased mechanical loads and excessive heating of the working surface during operation. The cost of the products is high, but if it is necessary to make holes in a hard alloy, then cobalt analogues are the best for performing such work.

Titanium drills are not inferior in strength to cobalt drills, and when drilling alloy steels and non-ferrous alloys they show even better results.

When used correctly, titanium models retain their factory sharpness for a long time, which will allow you to perform a significantly larger volume of work.

Inexpensive metal drills are made from ordinary high-speed steel P9 and P18. The cutting tool copes with its function perfectly, but the working surface quickly becomes dull, especially when a certain temperature threshold is exceeded.

Marking of cutting products

Marking drills for metal is necessary to determine the type of steel from which the cutting tool is made. The product also indicates its diameter, accuracy class and manufacturer (country). Only spiral gimlets with a diameter of less than 2 mm are not marked.

In other cases, drill markings may have the following meanings:

• P9 - made of high-speed steel with a tungsten percentage of 9%.
• P9K15 - indicates the presence of cobalt in the high-speed steel in an amount of 15%.
• Р6М5К5 - indicates the presence of a complex composition of cutting steel containing tungsten, cobalt and molybdenum.

Imported products have the HSS designation, which can be used to determine the composition of the material from which the drill was made. The HSS drill, which will be explained below, is used with an additional letter, which determines the presence of alloying metal.

HSS marking:

• HSS-E - contains cobalt. Used in processing metals of high viscosity.
• HSS-Tin - has titanium coating, which significantly increases the hardness of the working surface, and the temperature resistance of the material increases to +600 degrees.
• HSS-E VAP is a cutting tool used for processing stainless materials.
• HSS-4241 - designed for drilling aluminum.
• HSS-R - have maximum strength.

By marking the cutting tool, you can determine for what metal and in what mode the drill can be used. If the marking is not visible, then the purpose of the drill can be determined by the color of the product.

Visual identification of drill type

By the appearance of the cutting gimlet, you can determine the type of material from which the products are made and thereby find out the mechanical strength of the sample. By color you can determine the composition and quality of workmanship.

Grey

Gray drills are made of metal that has not been subjected to any additional processing.

The quality of the tool, in this case, leaves much to be desired, but for one-time use such products are quite suitable.

Black

This color indicates that the tool was treated with superheated steam. During processing, the product acquires greater strength.

It perfectly tolerates numerous cycles of heating and cooling of the metal, and also maintains the sharpening of the working surface for a long time.

The price of black metal drills is not much higher than gray products, so if you have a choice, you should give preference to tools of this type when purchasing.

Dark golden

This color indicates that the cutting tool has been tempered. This type of processing significantly increases the mechanical strength of the product as a result of reducing internal stresses.

With a tempered drill, you can successfully process high-strength metals, so if you are drilling too hard alloys, it is recommended to purchase a similar model.

Bright golden

The bright golden color indicates that metal made with the addition of titanium was used in production.

Despite the high cost of such models, it is much more practical to purchase a high-quality drill than to use cheap cutting tools, which will need to be used in large quantities for complex work.

Thus, it is easy to determine the quality of products by appearance and decide which metal drills are best to buy.

Classification by size

To choose the best drill and not overpay, it is enough to know what length sizes these products are usually divided into. If drilling metal does not require making deep holes, then purchasing models that are too long will lead to cost overruns.

It is customary to classify drills by length as follows:

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

When performing drilling work of various depths, you should select the tool that is most suitable for the specific task.

The best manufacturers

To purchase drills and be sure that the declared characteristics are completely true, you need to choose the right manufacturer.

Companies that value their reputation do not sell products of inadequate quality. Therefore, when choosing metal drills, you should give preference to manufacturers who have been on the market for a long time.

Among the newcomers, there may also be worthy producers. But in order to find out that a good quality product is on sale, you need to make a purchase, which often represents a “lottery”.

The best manufacturing companies:

1. Bosch - products of the German company have long proven themselves only on the positive side. Despite the rather high price of the products, when purchasing Bosch drills, you can rest assured of excellent quality. It is convenient and profitable to purchase tools from this company as a set.

Whatever set of drills you take, each one will contain only the highest quality products that will last for many years, provided they are properly stored and used.

2. “Zubr” is a domestic manufacturer whose products are maximally optimized in terms of price-quality ratio. You can purchase the products of this company either in a single copy or in the form of a set. The latter option will significantly save money, despite the significant cost of the kit.

3. Soviet-made drills - this category of cutting tools can be classified as an “endangered species.” With due diligence, you can purchase a rarity that has unsurpassed technical characteristics.

Conclusion

Which metal drills are best to buy depends on many circumstances:

1. If you need to drill several holes in very thin and soft metal, then just buy a cheap drill that will do the job.
2. For professional use, it is not at all profitable to purchase cheap drills. Low-quality products can lead to defects and significant time costs for frequent replacement of low-quality cutting tools.

(9 4,11 out of 5)

Source: https://plavitmetall.ru/oborudovanie/sverla-po-metallu-kakie-luchshe.html

What steel are metal drills made from?

Added by: Sergey Kolosov May 20

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

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

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

Features of choice

Professionals choose drills based on the following criteria:

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

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

Which material is better

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

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

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

Top quality drills - solid rolled

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

Choose by color

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

• Gray - cheap, low quality drills that have not been treated to increase strength and are susceptible to combustion;
• Black – treated with superheated steam, strong, durable, affordable;
• With a pale golden hue - machined durable drill bits made of hardened steel;
• With rich gold plating - expensive drills made of titanium with high strength and the most durable. The highest quality and most expensive drills have the corresponding color - gold

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

Marking

All data about the drill is printed on its shank

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

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

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

The highest quality drills are characterized by the USSR marking.

Main types of marking:

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

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

Sharpening angle

The sharpening angle is the angle between the edges

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

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

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

What size are drill bits?

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

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

They allow you to make holes of different depths.

What is a shank and what are they?

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

Shanks are:

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

   This shank shape fits almost any drill model

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

   Shanks designed specifically for rotary hammers

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

   These shanks provide the greatest torque

6. Conical - used in industrial hand drills and machines.

  Protecting metal from corrosion in water

Types of drills: types, purpose, features

Drills are designed to create holes in the material - both through and non-through (recesses). Drills are produced for a wide variety of materials that are used in production and everyday life: for wood and its composites, metal, concrete, plastic, stone, etc. Drilling occurs as a result of translational (along the axis) and rotational movement of the drill.

The material is cut using cutting edges, which can have different configurations and sharpening angles. Subtypes of drilling include drilling (making a blind hole) and reaming (expanding an existing hole to a larger diameter).

There are many types of drills, differing in purpose, configuration of the working surface, manufacturing method, type of material for which they are intended, etc.

Types of drills depending on the shape of the working surface

Screw or spiral. The most popular drill, used for drilling a wide variety of materials. The length of the twist drill can reach 28 cm, diameter – 80 mm.

Flat or feather. Used for drilling mainly deep, large-diameter holes. The working part has the shape of a blade, in the center of which there is a protruding point for centering. The blade can be integral with the shank or be replaceable and attached to the rod using a holder or boring bar.

Drill for deep drilling. Designed to make holes whose depth is at least 5 times greater than the diameter. The deep drill has two screw channels through which a cooling emulsion is supplied to the cutting area. The channels can be located inside the drill or in soldered tubes.

Single cut drill. Used for drilling holes that require increased accuracy requirements. Single-cut drills have a reference plane and two cutting edges located on one side of the center.

Core bit or annular drill. It looks like a hollow cylinder. Cutting is carried out by the cylinder wall on which the cutting edge is located. Drilling is obtained in the form of a ring, inside of which there is untouched material (core). After drilling, it usually remains in the crown; you just need to shake it out.

Center drill. It is used to drill (mark) the center.

Step drill. A relatively new type of instrument. They are convenient for drilling sheet material, especially in cases where you need to get a large hole in diameter - up to 3.5 cm or more.

According to the shape of the resulting hole, drills are divided into conical, cylindrical and stepped.

Shank types

Depending on the shape and method of fastening in the chuck or spindle, shanks are:

• cylindrical - the outer surface has the shape of a cylinder;
• conical - the surface is made in the form of a cone;
• faceted - there are 3, 4 or 6 edges on the outer surface;
• SDS type – shank for mounting in a chuck with a special locking mechanism.

The most common cylindrical drills in everyday life are fastened in a conventional chuck. Tools with a tapered shank are designed for use on machine tools. The SDS type shank is designed for mounting in a rotary hammer.

Drill manufacturing technology

Drills of relatively small diameters (up to 8-10 mm) are usually made from a solid rod of steel or alloy. The most commonly used high-speed steel grades are P9, P9K15, and P18. Drills of large diameters are made by welding; the cutting part is made of high-speed steel, and the shank is made of ordinary carbon steel.

For drilling hard materials - hardened and alloy steel, stone, concrete - drills are used that have soldered carbide plates made of pobedite or other hard alloy at the end. The cutting edges of the inserts can have different configurations: helical, beveled or straight.

Types of coating

Drills are coated for different purposes: protecting against corrosion, strengthening the surface layer, improving heat transfer, reducing friction. The most common and inexpensive operation is oxidation. The drill is coated with a black oxide film, which protects it from rust and overheating.

Titanium nitride (TiN) coating increases drill life by at least three times. However, such drills cannot be sharpened, since this removes the hardened layer. Titanium carbonitride (TiCN), also used for coating, is similar in properties to TiN.

Titanium aluminum nitride (TiAlN) makes the drill even more durable. When using it, the tool can work 5 times longer than usual.

Diamond coating is considered the most durable coating. This is not surprising. Diamond ranks first in hardness among other materials. Diamond-coated drills can be used for drilling almost any hard material, including stone.

What does the color of the drill mean?

The color of the coating can roughly determine the characteristics of the drill. Regular quality drills have a gray paint characteristic of steel.

Black color indicates that the drill has been oxidized. That is, it is protected from corrosion and has improved heat dissipation properties.

A light golden tint indicates that the drill has undergone a tempering procedure, during which internal stresses are relieved.

The titanium nitride coating reveals itself with the bright shine of gold. Drills with it have an increased service life and low friction when drilling. Although they are more expensive, they more than justify their price with long-term operation.

Diamond coating can be recognized by its yellow color and powdery texture.

Metal drills

For drilling metals (steel, cast iron, non-ferrous alloys), twist drills are usually used. Their longitudinal grooves do a good job of removing chips generated during drilling.

The processed materials have different hardness. Therefore, to drill them, drills with different hardness of the working part must be used. To process hardened, alloyed, heat-resistant steels, it is necessary to use solid carbide drills or those that have soldered carbide plates at the tip.

Wood drills

Relatively small holes up to 12 mm in wood or wood composites (chipboard, MDF) can be drilled with a conventional metal twist drill. But holes that are subject to increased requirements for dimensional accuracy and surface cleanliness are made with drills specially designed for wood. They are made from tool or carbon steel and are not suitable for metal.

Twist drills. Designed for drilling small and medium-sized holes. As already noted, you can use twist drills for metal instead, but the holes after them are of poorer quality.

Screw drills. They have a sharp cutting edge and a screw-like shape. Thanks to the latter, chips are easily removed from the hole. These are high-quality drills that are used if you need to get a deep hole with a smooth wall.

Feather drills. They are used to produce holes of relatively large diameters - from 10 to 25 mm or more. These are the simplest and most inexpensive drills, you can even make them yourself from a suitable plate and a round rod. But the quality of the holes after them is low - rough walls, not very accurate dimensions.

Crown. The term “crown” means that this tool is made in the form of a hollow cylinder, on the edges of which there are teeth. The drilling is obtained in the form of a ring, from which the inner part is then removed. A crown is an indispensable tool if you need to get a large hole - up to 100 mm or more. In stores it is offered in the form of a set, which contains a mandrel, a centering drill with a shank and several crowns of different diameters.

Forsner drill. This is a tool for making precise holes in wood (especially soft wood), chipboard, laminate, etc. It has a centering point and a sharp-edged scorer. Thanks to the latter, the hole is precise and smooth. If you need to get a blind hole with smooth walls and precise dimensions, a Forsner drill will do the job best.

Drills for stone materials

Conventional metal drills are not suitable for drilling brick, concrete, natural or artificial stone. They instantly become dull. A drill or drill for stone materials must have a carbide tip.

The operation itself of drilling concrete, brick or stone also has its own peculiarities. In addition to the rotational movement, the drill or drill inserted into the hammer drill also performs a percussion-translational movement. That is, the stone, in fact, is not cut, but crushed.

A drill or drill bit for a hammer drill can have a regular cylindrical or a special standardized SDS type shank (SDS-top, SDS-max or SDS-plus). Its advantage is that the insertion and removal of the drill from the chuck is carried out without a key and very quickly, in one movement.

Small and medium-sized holes in brick and concrete are drilled with a drill or a drill with a carbide tip. The tool has the shape of a screw.

If you need to drill a large hole, then use a crown with carbide teeth or diamond coating. Drilling can be wet (with water supplied for cooling) or dry. At the end of drilling, a core remains inside the crown - a cylindrical piece of cut material.

Carbide inserts soldered to a drill or auger have different hardnesses. For drilling granite, drills with high-hardness pobedite plates are used. For working with concrete or brick, medium or soft hardness Pobedit grades are suitable.

Drills for ceramics and glass

Ceramic tiles or glass are drilled with a crown or a special spear-shaped tool. Its tip is made of either pobedite or tungsten carbide. If a specialized tool for glass or tiles is not available, you can use a concrete drill. It just needs to be sharp, and you need to work with it carefully, since its shape is not entirely suitable for such work.

Spear drill bit for ceramic tiles and diamond-coated bit.

A crown for glass and tile is almost no different from a crown for stone. Only on its cutting edge instead of teeth there is a diamond coating.

A tool called a ballerina is used to drill large holes in tiles. It resembles an ordinary compass. Drilling is done from the underside of the tile. The drill speed is set to minimum.

Universal drills

In addition to the above specialized drills, there are also universal ones. They can process almost any materials - brick and concrete, tiles, wood, plastic, aluminum, steel. Universal drills have a clever sharpening that is capable of cutting any material. This is very convenient in cases where you have to work with different materials simultaneously. For example, when renovating an apartment.

Source: https://iambuilding.ru/stati/tool/sverla-tipy-naznachenie-osobennosti/

Drill. Types and types. Operation and application. Peculiarities

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

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

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

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

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

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

Conical

Such a drill can usually be found clamped into a specialized machine. Its working part is a cone, the top of which cuts into the surface of the metal, forming a thin hole. As you move deeper into the material, contact occurs with a wider part of the cone, which causes the hole to widen.

Thanks to the use of this design, drilling can be achieved in one pass. For example, if you use a regular twist drill, you first need to make a hole with a thin tool, and then with a thicker one, gradually bringing the diameter to the required parameters.

The cone shape allows you to avoid such inconveniences, but unfortunately, it is not suitable for weak drills.

Crowned

The crown structure is a hollow cylinder, at the lower end of which there are sharp serrations resembling a crown. This tool allows you to make large diameter holes, ranging from 30 mm or more. The disadvantage of this design is that it cannot be installed in a conventional drill chuck.

The tool can be used for drilling sheet metal up to 10 mm thick. Typically, HSS steel is used to make hole saws. Also on the market you can find drills with carbide tips or diamond coating. They allow you to work not only with metals and alloys, but even with concrete.

Stepped

The stepped design is one of the latest inventions in the world of cutting tools. It has universal application because it allows you to make holes of various diameters. The name of the type is due to the fact that it is a cone with steps.

This drill can only be used for working with sheet metal up to 2 mm thick. The principle of operation is that the tip of the tool cuts into the material, and when it breaks through, it contacts the wider part of the cone, which drills the recess even further.

Thus, in order to obtain the required diameter, you need to go deeper to the desired step.

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

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

Spiral on wood

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

Screw

Twist drills resemble twist drills, but have a more advanced working part for removing chips. They are quite long, so they allow you to make deep holes. They are often used for drilling beams and logs.

Often such a drill has a special handle, which allows you to work even without using a drill, machine or brace. The pointed part of the tool resembles a screw; it cuts into the wood, pressing the cutting edge against the grain.

The cut is clean and neat, even when working with raw wood.

Hole saws

This tool is a hollow cylinder with saw teeth on the end and a conventional twist drill protruding forward. It allows you to make holes in boards, plywood and lining. It is usually used to obtain wide openings necessary for installing lamps.

The tool is suitable not only for wood, but also for polystyrene foam, PVC lining and cellular polycarbonate. Such drill saws can be used to cut into a seat when installing a socket in a wall, of course, provided that it is wooden or made of soft blocks - foam concrete, clay, etc.

The selection of the central part can be completed using a chisel.

Ballerinas

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

Forstner drill

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

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

• Spiral.
• Screw.
• Crowned.

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

On glass

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

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

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

Related topics:

Source: https://tehpribory.ru/glavnaia/instrumenty/sverla.html