What are the drills. The main types of drills and their practical application. Types of drills and their purpose

The purpose of any drill is to create various types of recesses and holes in a given material. This process occurs due to the rotation of the cutting element around its axis. In addition to creating new holes, using these tools, you can also expand old ones that have a small diameter. According to their design, application and production method, all types of drills have noticeable differences. Let's consider them in more detail.

Classification by type and shape of the working part

Because of different kind tasks and functions, the elements have a different form of the working part and are classified as follows:

• Screw type drill. Its second name is spiral. It is the most common, because in everyday life it is used most often. This tool, the length of which is from 5 to 20 or more centimeters, will help in drilling both wood and other types of materials: metals, ceramics, concrete. The line of models of spiral instruments is available in diameters from 0.1 mm to 3 cm.
• Drill flat type. It is shaped like a feather. This feature gave him another name - feather. First of all, it is used to create deep holes of a relatively large diameter. The cutting element of such a tool is made in the form of a blade.
• To perform a deep drilling robot, long products are used that have two screw channels. A special fluid flows through them, cooling the tool during the working process. In most cases, the channels are placed inside the drill.
• There is also such a type as a single-sided cutting drill. It is used only in cases where the future hole must be made with high accuracy. Thanks to the single reference plane and the location of both cutting edges on the same side of the axis, the result of work with this tool is of high quality.
• Ring type drill. Structure of this type interesting in that it is hollow inside. Thanks to this design, a narrow ring comes out during drilling. These types of drills have another name - crowns.
• To make a center hole, you can use the so-called centering product. It is available at any hardware store.

As a result, we can conclude that there are various types of drills. And their purpose is also different. Let's look at sharpening methods.

Types of sharpening drills

Having considered the types and shapes of work surfaces, it is necessary to disclose the issue of sharpening these elements. The process, or rather its type, depends entirely on the tasks that will be performed by this tool.

There are the following types of sharpening:

• Ordinary, spiral. It is applied to works with steel, non-ferrous metals, plastic.
• For cast iron. The name speaks for itself - for work with a mixture of cast iron.
• Transverse undercut on the edge. For all types of drilling work.
• With center point. For work with soft materials.
• Cone-shaped with a point.
• Finished with pointed bridge and main blade for adjustment. Used for hard steel.

Classification by shank design

There is a classification of drills, the main criterion of which is the structure of the back part - the tool shank.

According to this classification, there are the following:

• Cylindrical type.
• conical.
• Faceted. With six, four or three edges.
• SDS products.

Production technology

Some types of drills are made from a solid piece of metal. These include instruments whose diameter exceeds 8 mm. Drills with a diameter of up to 6 mm are made from alloys.

This is a special steel, which is also called high-speed. Those types of tools whose diameter exceeds 8 mm are made by welding. The shank of such products is made from carbon steel alloy. And the cutting part is made of alloy. For processing fragile and brittle materials (soft woods, some metals), a drill with such tools is equipped with grooves different shapes. There are straight, screw and beveled types.

Hole shape classification

The shape of the holes produced is another method for classifying products. According to this characteristic, they are divided into the following types:

• Conical shape.
• Square.
• Stepped.
• Cylindrical.

Coating classification

The material that the drill is coated with is a very important characteristic of the tool.

The coating determines the durability and efficiency of a given tool. According to this parameter, the following products are available:

• The budget option for coating the drill is an oxide film. The function of this coating is to protect the tool from corrosion and protection from overheating. Thanks to the oxide film, the service life is increased.
• Ceramic type coating. It is made from titanium nitride. Due to this, this type of coating increases the service life of the tool by three times. But there is one downside. These drills must not be sharpened.
• As a derivative of the past type of coating, titanium-aluminum nitride was created. In this case, the drill resource is increased by 5 times.
• Similar in action to titanium-aluminum nitride is titanium carbonitride.
• The most durable and wear-resistant are tools that are coated with diamond coating.

Types of drills for metal

For work on non-ferrous metals, cast iron and steel, spiral products are perfect.

Chips that are formed during machining go through the machined grooves. Drills for metal work differ not only in the material and coating from which they were made, but also in the type of shank. To determine the quality of a tool, you do not need to be a high-class specialist. It is enough to look at the color of the coating. Low quality tools have a gray tint. If the color of the product is black, this is a sign of a higher quality. A drill with a bright golden hue indicates that the tool is coated with titanium nitride and its quality is excellent. Speaking about the strength of the material itself, from which the drill is made, it can be noted that it must be carbide. After all, metals themselves have high strength. Therefore, for their processing, a material is needed whose strength will be greater.

For wood processing

When it is necessary to make several small holes in wood material, the simplest is suitable for this. For high-precision work, or when a large hole is needed, special woodworking tools are used. They are made from tool steel, carbon-containing or alloyed. For metal work, such a tool is not used.

Types of wood drills:

• Spiral type.
• Helical.
• By type of pen or pen.
• Crowns for woodworking.

For working with concrete

To work with more durable surfaces (concrete, brick, stone), you will need a very strong product that has a hard tip. The alloy from which the species are made has high strength characteristics. The work of such a tool is carried out using shock-rotary mechanisms (perforator). Most often, SDS shanks are used for this type. To carry out a certain drilling, the types of drills must be selected of the appropriate type. To make a small hole in hard concrete, a hard-tipped auger drill should be used. For large holes it is necessary to use special toothed carbide bits. As a rule, they are coated with diamond dusting. This is necessary for greater efficiency and longer service life.

Drill - a type of cutting tool for drilling through holes or recesses (not through) in materials of various hardness, as well as for increasing the size (width, depth) of existing recesses and holes.

The drilling process is carried out progressively along the axial rotational movement. The material being processed is destroyed (cut off) by the side cutting edges of the drill located along the working length of its body, which have a different shape and angles of the sharpened edge and the drill tip.

Drilling (drilling) by these devices is carried out by various mechanical (rotary) and electrical devices (drill, screwdriver, puncher, etc.).

Types of drills and their purpose

According to their types, drills are divided according to the following criteria:

• drill assignment.
• the configuration of the tip, the surface of the working fluid and the tail of the drill.
• preparation method.
• the type of materials they are intended for drilling, and so on.

Let's analyze the key types of drills in more detail.

Drilling materials

Any natural or artificial, that is, man-made, material in certain cases needs holes. When we say “natural materials” and “certain cases”, we mean drills for medical purposes (dentistry, surgery, etc.), drilling for oil, gas and other similar options. Well, it makes no sense to talk about the need for technological, technical, decorative and other holes because of their obviousness.

The most famous drilling materials in everyday life are:

• wood;
• metals;
• stone (brick, concrete).

There are also special drills for working with ceramic and glass products.

There are special drills for the production of work with ceramic and glass products.

Types of drills for drilling different materials according to the design of their working part

So, depending on the features of the device of the working part, drills are distinguished:

• Screw. The most famous and common type of drills in domestic use. The drill diameter varies from 0.1 to 80 millimeters. The length of the working fluid reaches 275 millimeters. This configuration of the working part of the drill is considered universal and is suitable for materials of any type of hardness.
• Flat (feather) drills. Designed for work with soft materials (wood, plastics, etc.). A special device, a cutting plate of different widths, allows you to create holes and recesses of large diameters.

• Drills of Zhirov, Forstner, Yudovin and Masarnovsky, named after their inventors, which implies their technical structure.
• Drills designed for deep drilling. Features: an elongated screw body with 2 channels for bringing coolant to the drilling point.
• Single sided cut.
• Cannon drills.
• Gun drills.
• Centering, hollow, step drills.

With the exception of screw, spade and personalized drills, their other types have a narrow professional focus and are used in drilling, boring and other production machines.

Types of drills for metal

Drills used for work with metals of various hardness are divided into:

• screw (spiral);
• drills - crowns;
• cone drills.

Depending on the metal being processed (non-ferrous, black, alloy steel, etc.), the alloys used for their manufacture also change. And not necessarily the entire length of the working fluid, but only the tip of the drill.

Types of wood drills

• spiral (screw);
• flat feathers.

A characteristic feature of drills for working with wood and materials based on it (fiberboard, OSB, plywood) is the presence of a pointed, sharp end on the tip, which ensures drilling accuracy when stuck into the material. They can be of various diameters and lengths.

Drills for concrete work

Unlike drills for metal, which are also drills for woodworking, drills and drills for concrete are considered highly specialized, due to the structure of the entire drill.

The tip of the drill is made of hard alloys and has a specific shape.

Since, in addition to the usual rotation along the axis, stone work involves translational-impact movements, the working surface of the entire drill is also made of metals of special strength or hardening.

The use of a perforator as a tool is reflected in the shape of the drill shank. It can be 4-, 6- and 8-angular in shape with a longitudinal groove along the length of the tail end.

For drilling large diameter holes in concrete, so-called pobedit or diamond crowns in the form of an auger are used.

Types of sharpening drills

Depending on the material being processed, the type of sharpening of the drill changes, that is, the change in the angle of inclination of the sharpened cutting edges. For sharpening professional drills, there are special machines and technological tables indicating the degrees of inclination for different groups of materials.

Drilling metal is one of the most common plumbing operations. Collapsible and non-collapsible connections - rivet, screw, bolt, hairpin - require holes. To drill metal, it is enough to have a drill, a drill of the appropriate diameter and a center punch with a hammer for basting the hole.

Drill selection

If holes in the metal are drilled for threading, then according to GOST 24705-81, for the most commonly used thread sizes (for standard large pitches): M4, M5, M6, M8, M10 and M12 - the diameter of the drills will be 3.3, respectively; 4.2; 5; 6.7; 8.4; 10.2 mm. It is quite acceptable if drilling for threading will be carried out with a drill, the diameter of which differs slightly (by 0.1 mm) from the GOST dimensions in one direction or another.

When purchasing drills, you need to keep in mind that conventional drills made of high-speed tool steel (for example, R6M5) are designed for drilling metals that do not have high hardness. To drill through hard metal, carbide drills are required. These drills can be full carbide or have only a carbide tip.

Sometimes, before starting drilling, it is not known what hardness the metal is to be drilled. Therefore, when you see at the first moment of drilling that the drill does not penetrate into the metal, you must immediately stop drilling, otherwise the drill will be irrevocably disabled, overheating and losing hardness. Evidence of this will be the appearance of a dark blue color on it. Before drilling metal, the hardness of which is not known, you can run a file through it. If the latter does not leave traces on the metal, then the material has increased hardness.

How to drill metal

Optimal for drilling most metals are low and medium speeds - 500-1000 rpm. High RPM the drill is heated quickly, as a result of which its annealing and softening can occur. When drilling, do not press too hard on the drill, the feed should be slow and smooth.

When drilling metal, the sharpness of the drill is very important, while the drill becomes dull very quickly. The rate of blunting of the drill depends in particular on revolutions, feed force, cooling and other factors, however, no matter how hard you try, if a non-aluminum alloy is being drilled, the drill's operating time to unsatisfactory performance is measured in minutes.

Before drilling, it is necessary to mark the hole by punching it. To do this, you need to install the tip of the center punch (or dowel) in the intended center of the hole and hit it with a hammer. Piercing is necessary to prevent slipping of the drill at the first moment of drilling. If the core mark is not large enough to hold a large diameter drill, then first widen the hole with a small diameter drill.

For creating better conditions drilling, it is advisable to dip the tip of the drill into machine oil or drop it into the place of punching. The oil in the drilling zone contributes to better cooling of the drill and facilitates metal cutting. A drill drilled with oil is less blunt, requires less sharpening, and lasts longer. A special emulsion, soapy water, kerosene are also used as a coolant. According to some craftsmen, lard is a good lubricant and coolant. Before drilling, a rotating drill is immersed in a piece of fat, which melts during drilling and has a lubricating and cooling effect. But still the simplest and most convenient remedy is soapy water. It does not stain, and there is soap in every home. It is enough to drop it once at the beginning of drilling and in the process. You can periodically dip the drill in a soapy solution.

When through drilling with a high feed, a burr (burr) is formed at the exit of the hole, for which the drill clings to its side cutters. As a result, a sharp blocking of the drill and its fracture or chipping off of the cutter can occur, and even at this moment the drill becomes particularly intensely blunt. Such stops also have a negative effect on the state of the drill. To avoid the formation of burrs, you need to finish drilling holes in metal with a low feed. It is also advisable to place a wooden block under the drilled part, which prevents the formation of a burr. The bar and the workpiece must be tightly pressed against each other. For greater effect, you can put not a wooden block, but a plate of the same or less hard metal, which should be tightly pressed to the exit point of the drill.

Most often, it is necessary to drill steel, but it is often necessary to drill other metals, which have their own drilling characteristics. Aluminum, for example, envelops the drill, making it difficult for it to penetrate deep and widening the resulting hole. If you want to drill a precise hole in aluminum (for example, for a thread), you must always apply coolant and remove the drill from the hole more often to clean it. Ordinary gray cast iron is relatively easy to drill and does not require coolant or lubrication. But drilling in cast iron can bring surprises. There are ductile gray cast irons that need to be drilled with a carbide drill bit. White cast iron, the main structural component of which is cementite, is very hard, it requires a high-strength drill.

Large diameter holes should be drilled in stages. First you need to drill the part with a thin drill, then drill the hole to a larger diameter. For example, a hole with a diameter of 12 mm is best drilled in two or three steps - sequentially with 5, 10 and 12 mm drills.

Blunt drills need to be sharpened in a timely manner. It is better to do this with a sharpening tool, but you can do without it. In this case, you need to pay attention to the symmetry of the tip of the drill. If the sharpened edges do not meet strictly in the center, the hole drilled with such a drill will have a larger diameter, since one cutting edge will be longer than the other. The standard point angle (the angle between the cutting edges) is 118°. For drilling aluminum, an angle of 130-140 ° is considered optimal, soft bronze and red copper 125-130 °. However, all these metals can be drilled with a standard angle drill. Read more about drill sharpening.

When drilling, it is necessary to maintain the verticality of the drill relative to the metal surface (if it is not required to drill an inclined hole). When making holes in thin sheets, this requirement is not as relevant as for thick-walled or hollow parts. Drilling pipes, for example, often leads to the fact that the inlet and outlet holes are offset relative to each other - the more, the larger the diameter of the pipe. It is quite difficult to maintain the perpendicularity of the drill by eye, so you can use home-made or purchased drilling jigs or guides that ensure the perpendicularity of the drill.

Conductors are also needed for drilling two or more holes in mating parts. The best way to ensure the holes match is to drill them as an assembly. When drilling rivet holes, complete drilling is a must. Having drilled the first hole, you can use it to connect the parts with a bolt so that you can drill the remaining holes without fear that the parts will move relative to each other. If it is impossible or inconvenient to drill mating assembly parts, then a jig or guide must be used. You should know that no matter how accurately the mating holes are marked and punched, they will still not match absolutely exactly, since when drilling even a punched hole, the drill will go a little to the side.

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A drill is one of the most essential tools for a craftsman. Drills are required where it is necessary to create a recess or hole in some material. The choice of drills is huge, they have different purposes, the design of the working part, different shanks, they can be of different sizes, they differ in the manufacturing method.

The classification of drills should begin with their design. We are talking about the most important thing - the working part of the tool. So, according to the design of the working part, all drills are divided into the following types:

• Screw or spiral. The most common and popular option. The diameter of screw drills can vary from 0.1 to 80 mm, and the length of the working part can reach 275 mm.
• Stepped. Convenient in that one drill can be used to create holes of various diameters. Used on sheets.
• Flat. Their cutting part of the plate is a blade, a feather, so they are also called feather blades. Used to create large holes.
• Long screw drills are needed where a hole of a sufficiently large depth is required. They have screw channels for supplying fluid needed for cooling during drilling.
• Centering. Such drills are needed to create center holes in various parts.
• Hollow drills are also called core drills or ring drills. Only the annular narrow part of the material turns into chips.
• Drills for unilateral cutting. Such a tool is needed to create a hole with particularly accurate dimensions. The drill has a reference plane, both cutting edges are located on the same side of the central axis.

This photo clearly shows almost all types of drills. They are divided by purpose, that is, the material with which they are intended to work:

• A - drill for metal;
• B - for wood;
• C - for concrete;
• D - flat, it is also a pen drill, also for wood;
• E - universal drill, can be used for both concrete and metal;
• F - for working with sheet metal;
• G is another universal drill that is successfully used in plastic, wood, and metal.

Drills for working with glass and ceramics are also distinguished separately; diamond coating is usually applied to their tip.

As for the difference between drills according to the type of shanks, that is, the part that is attached to an electric tool or handle, they are:

• 1 and 2 in the diagram are cylindrical shanks;
• 3 - marked as SDS-plus;
• 4 - hexagonal shank;
• 5 - shank with four faces;
• 6 - trihedral shank;
• 7 - such drills are intended for screwdrivers.

Drills also differ in the shape of the hole that can be created with their help:

• cylindrical;
• conical;
• stepped;
• square.

If we talk not about the scope and types of construction, but about the features of the manufacture of the tool, then the drills are divided into the following types:

• Whole. These are always spiral, screw drills. To create them, steel is used, which belongs to the high-speed type. These are the brands P18, P9, P6M5, P9K15, P6M5K5. Carbide can also be used.
• Welded. The working part of such a twist drill is made of high speed steel, but carbon steel is used for the shank.
• With carbide inserts. Such drills come with oblique, straight and helical grooves.
• With replaceable carbide inserts or replaceable carbide heads. The first type is also called body drills.

It seems that the quality of the drill is difficult to determine. However, you don't need to be an expert to do this. A lot can be said about the quality of an instrument by its color.

If the drill is ordinary inconspicuous gray color, this will speak of its low quality. These tools are widely used, but they wear out fairly quickly. The black color of the drill indicates that at the end of the manufacturing process it was treated with superheated steam. The quality of the black drill will be slightly higher than that of the gray one.

A light shade of gold will be in the drill, which was processed with the help of a vacation. This is done to relieve internal stress. A brightly shining gold-plated drill was coated with titanium nitride. The highest quality drills, although their price will be noticeably higher than that of ordinary gray ones, but the tool will last a long time.

Drills differ in size. About the minimum and maximum diameter drills can have, we already wrote above. Of course, the diameter of the hole they create will also depend on the size of the tool.

Usually drills are bought in a set. In fact, you cannot say exactly when and what tool you will need. Convenient kits in the form of a suitcase do not take up much space and allow you to choose the right drill.

Craftsmen who often use various drills usually create convenient storage places in the form of a stand on the desktop. So the tool is always at hand and definitely will not be lost in the workshop.

As you can see, the classification of drills is quite extensive, as are the types of work for which they are intended. Choose a quality tool, you can universal, but experts still advise giving preference to drills that are intended for a particular material.