Hole drilling now large diameter in metal is not a serious problem... The main thing is to prepare well. Let's say you need to make a hole in a corner, channel or mortgage in order to strengthen building structure or hang a shelf, lamp or duct. That is, to do this not in a workshop or workshop, but directly at the place. The easiest way to drill in such conditions is to use an electric drill. But, imagine how much pressure you need to apply to drill a hole with a diameter of 16 or 20 mm? The question is not rhetorical - the effort will be about 40-50 kgf. This is not easy to achieve if the intended hole is located above the level of the driller's shoulders. Even 10 years ago, when such a problem arose, even professionals resorted to autogenous and, just imagine, to drilling small holes around the circumference of a large one. Today, there is a completely professional solution for this - core drilling, which ensures the production of holes of 11 quality.

However, many are convinced that core drilling is a rather expensive method, cost-effective only in industrial volumes. Is this statement true? Partly. Today, you can choose several options for tools and equipment for drilling a hole in large diameter metal without reaming. In this case, the cost per hole will be justified even when drilling only a few holes.

Consider what tool options the market offers for drilling large-diameter through holes in metal... For comparison, we take a diameter of 51 mm.

First, it is bimetallic crowns... Samples from the cheapest are presented to choose from, which are immediately sold in sets and cannot be accepted by us in this review for the reason that their purpose is to drill wood, and if they do succeed in drilling a sheet of metal, then it will not be thicker than 0.5 mm ... At a price of 240 rubles, products with a wall thickness of 1-1.2 mm start, often they are marked HSS -Co 5% and even HSS -Co 8, but judging by the fact that drilling one hole in stainless steel takes more than one such crowns, cobalt there may not be at all. Twice as expensive bits of more decent quality, really allowing you to drill stainless steel and ordinary steel a few millimeters thick. Bimetallic crowns this level allows you to drill 5-20 holes in a steel sheet with a thickness of 5 mm. At the same time, the use of any lubricating-cooling composition ensures that the upper bar of this range is reached. The third stage is occupied by bimetallic crowns worldwide famous brands, which are even twice as expensive, can be equipped with special devices for a quick change in the drill, but in terms of resource they do not much or do not exceed the average price level.

Drilling large holes in steel sheets with a thickness of more than 5-6 mm for bimetallic crowns it is very difficult, although sometimes you can hear a different opinion. It is based on data on the total drilling depth of such crowns - 35-38 mm. As a rule, only sellers of bimetallic crowns, who do not have a more worthy tool in their assortment, risk advising to drill a 30 mm sheet or beam in this way. The fact is that a bimetallic crown is devoid of a chip-evacuation groove, and as soon as the thickness of the drilled metal becomes greater than the height of the crown tooth, problems with chip evacuation begin. In addition, the body of the bimetallic bit is not entirely cylindrical in shape, this causes jamming in the metal of a solid thickness.

In contrast to bimetallic bits, they provide more accurate drilling. Carbide body hole saw- chiseled, while the bimetallic crown is rolled from a tape and welded into a ring. There are several types of carbide drill bit designs. Without delving into the types of shanks and types of attachment, we will analyze only the cutting part. The most expensive part of the crown is the carbide teeth. The quality of the material greatly affects the drilling speed, impact resistance, bit life and the ability to drill alloy steels with a high chromium content.

The second feature that you need to pay attention to is the shape of the tooth and its size. For drilling thin sheet steel, thin stainless steel and non-ferrous metals, a narrow tooth with a flat profile, slightly beveled inward, is used. Such crowns also do not have a chip groove, and they will not be able to drill metal thicker than the height of their tooth. The price of such bits is two to three times higher than that of bimetallic bits, depending on the design of their case, they can be designed or. Since this professional samples, at present, their counterfeits are not widespread, and almost all samples found on the market are of acceptable quality, but excellent quality you need to choose from manufacturers specializing in these products.

Thicker metal can be drilled. In these bits, every second or, as a rule, one of three successive carbide teeth is sharpened in a different way. This ensures a soft cut, no vibration, less stress on the cutting edges and, as a result, an increase in the life of the bit. In such crowns, there is a short or long chip-removal groove, almost to the entire height of the wall. The first version of the crowns allows you to drill metal up to 12 mm thick, and up to 25 mm. It is this version of the tool for drilling a hole in metal of large diameter that is the most progressive, providing the best performance and quality. The price of such crowns is 20-30% higher than that of thin-walled and in absolute terms is 1880 - 1910 rubles, as we agreed, for a crown with a diameter of 51 mm. As everywhere in nature, there are deviations in one direction or another up to 2 times, but, as usual, considering builds a golden mean.

The option in which the metal is quite thick, say 10 mm, and the hole diameter is 20-25 mm can be solved. It is recommended as a drive, but an electric drill can also be used. With the above-mentioned machine, investments will amount to 21,164 rubles excluding VAT, and with a drill - 5,000 - 5,500 thousand.

For a hole with a diameter of 50-60 mm, with such a metal thickness, the use of a magnetic or stationary drilling machine... A large load causes a high cost of investment in equipment, and together with a crown it will amount to about 56,000 rubles, or, option with magnetic drill stand and a separately purchased drill for about 50,000. To drill such holes with a drill from your hands is not only difficult, but also dangerous.

Drilling with a manual electric drill in metal up to 5 mm thick holes of large diameter is not difficult when using both bimetallic and carbide bits. The choice of the tool is carried out depending on the required accuracy. When drilling holes with a bimetallic bit, the ovality of holes and an increase in diameter from the desired one can reach 4% or in absolute terms - 2 - 3 mm. When drilling with a carbide bit, only 0.6 - 1 mm. In addition, all of the carbide bits presented in the review, and almost all of the metal bits on the market, drill stainless steel as well.

Metal processing is carried out not only in an industrial environment. While doing renovation works by car, manufacturing of structures on personal plot or carrying out repairs to the home, it is necessary to drill holes in the metal. At home, a hand drill is most often used.

This versatile tool requires specific skills to work with solid products. You can purchase or make your own machine for drilling holes in metal, but this is not a cheap pleasure.

The technology of drilling holes in metal consists in removing a thin layer of material due to the simultaneous translational and rotational movement.

The main condition for high-quality and safe (for the tool) machining is to keep the chuck axis in a fixed position. With the help of a machine, it is easy to maintain straightness, which cannot be said when working with a hand tool.

If you are unsure of the firmness of your hands (this is normal for an ordinary person), for drilling at right angles, mechanical assistants (conductors) are required.

Let's make a reservation right away that additional conductors are required only when the metal thickness exceeds the drill diameter.

If you're making a hole in a thin steel plate, straightness doesn't matter.

There are several types of electric hand drill guides. Power tools are poorly suited for metalworking, especially when it comes to precision.

1. Drilling jig. It is made in the form of a body, convenient for holding, inside which there are guide sleeves for drills of various diameters.


The material of the bushings is harder than the tool, so the holes do not wear out. By positioning the jig exactly over the center of the intended hole, you do not have to worry about the drill going away from the intended direction.

This device is especially useful when drilling. perpendicular holes in pipes with a small diameter, when the tip tries to slip off the cylindrical surface.



2. Drill guide (manual). Supporting device in which the instrument is fixed by the neck


The sole is placed on the workpiece, holding the handle with the other hand. The drill moves strictly vertically, avoiding distortions and drifts of the drill.

The design can have an angle holder for small diameter pipes, which makes the fixture more versatile.

In the presence of swivel mechanism, you also get an attachment for drilling holes at an angle.


True, the metal cannot be drilled in this way, the lateral loads will quickly break the drill.

3. Drill stand (semi-stationary). In fact, it is an inexpensive alternative to a drilling machine.

Why do some people drill in metal quickly and without any particular difficulties, while for others it resembles an epic, accompanied by broken and blunt drills?

Drill selection

Drilling into metal parts is usually done using twist drills that have two cutting edges in the working part and two helical flutes for evacuating the chips.

The most common are drills made of R6M5 steel, drills with cobalt in the marking have the letter K (R6M5K5), such a tool blunts more slowly, but also costs more.

More high rates drills with titanium spraying have strengths. They differ from the rest of the instrument with a yellow coating.

In addition, there are also stepped ones, having a herringbone appearance in longitudinal section. Made of high speed steel, they have a pitch of 2 mm, which allows them to be performed in sheet metal holes with a diameter of 4 to 36mm.

Lubrication and Cooling

In the process of drilling metal, the drill under the influence of frictional forces can become very hot. Due to overheating, the hardness of the drill decreases and it loses its cutting properties.

This can be avoided both by cooling the drill and by reducing the friction force. For the simultaneous lubrication and cooling of the drill, there are special cutting fluids and paste formulations.

Before starting work, a liquid lubricant is applied to the drill with a brush or injected with an oiler into the drilled hole, the paste is applied to the drill just before drilling.

At home in the absence special means machine oil can be used for lubrication and cooling; drilling of ordinary gray cast iron is performed "dry".

Drilling technology

Before starting, be sure to make a small indentation in the center of the future hole using a punch and a hammer. This will avoid drifting towards the drill. initial stage cutting it into the metal.

Place a piece of board of the appropriate size under the metal blank. The part will slip less and the edges of the exit hole will be much cleaner.

Hold the drill so that the drill is exactly perpendicular to the plane of the workpiece. Otherwise, the drill will deviate from the intended axis, and the thin one may even break. The use of a special drill stand, spacer or guide makes the work much easier.

At the initial stage of drilling, the pressure on the drill should be barely perceptible. The pressure can be increased slightly as the drill cuts into the metal.

The indicator of the correct selection of pressing force is the chips ejected by the drill. Small chips will indicate that the pressure needs to be increased, thin chips will indicate normal feed, and thick spiral chips will indicate the need to reduce the force on the drill.

Most of the mistakes novice craftsmen make when choosing the speed of drilling in metal, setting the rotational speed of the drill too high. As a result, the drill overheats, dulls quickly and becomes unusable.

When drilling metal with a drill with a diameter of 3-4 mm, its rotation speed should not exceed 1000 rpm. With an increase in the diameter of the drill, the speed of the drill should decrease proportionally, reaching 400 rpm for drills with a thickness of 13 mm or more.

By doing through hole, Special attention pay attention to the final drilling phase. The lateral incisors of the drill can catch a burr formed at the exit of the hole, which can lead to sudden blockage or even fracture of the drill.

Always follow the completion of the drilling process by reducing the pressure on the tool.

If it is necessary to drill a large hole, first pre-drill using a drill with a diameter of 3 to 5 mm. Then drill it with an 8 mm drill and only after that, use a drill of the required diameter in the chuck of an electric drill.

This approach will cut metal more efficiently and faster, reducing the chance of skew.

Good luck to you! May you succeed!

Drilling in metal is one of the most common locksmith operations. Dismountable and non-dismountable joints - riveted, screw, bolted, stud - require holes. To drill in metal, it is enough to have a drill, a drill of the appropriate diameter and a center punch with a hammer to mark the hole.

Drill selection

If the holes in the metal are drilled for the thread, 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 drill diameter will be 3.3, respectively; 4.2; 5; 6.7; 8.4; 10.2 mm. It is quite acceptable if drilling under the thread will be carried out with a drill, the diameter of which slightly (by 0.1 mm) differs 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, P6M5) are intended for drilling metals that do not have high hardness... To drill through hard metal, you need carbide drills. These drills can be all-carbide or have only a carbide tip.

Sometimes, before starting drilling, it is not known what hardness the metal is to be drilled. Therefore, having seen 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 damaged, overheating and losing its hardness. This will be evidenced by the appearance of a dark blue color on it. Before drilling into metal, the hardness of which is not known, you can file it over it. If the latter does not leave traces on the metal, then the material has increased hardness.

How to drill metal

Low and medium speeds - 500-1000 rpm are optimal for drilling in most metals. High revolutions quickly heat up the drill, which can cause annealing and softening. When drilling, do not put too much pressure 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 blunt very quickly. The bluntness rate of the drill depends in particular on the revolutions, feed force, cooling and other factors, however, no matter how hard you try, if a non-aluminum alloy is drilled, the operating time of the drill to an unsatisfactory performance is measured in minutes.

Before drilling, mark the hole by punching it in. 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. Punching is necessary to prevent slipping of the drill at the first moment of drilling. If the core track is not large enough to hold a large diameter drill, the hole should be widened with a small drill first.

For creating better conditions When drilling, it is advisable to dip the tip of the drill into machine oil or drop it into the center of the punch. Oil in the drilling area helps to cool the drill and makes it easier to cut metal. The drill, which is drilled using oil, dulls less, requires less sharpening and lasts longer. A special emulsion, soapy water, and kerosene are also used as a coolant. According to some experts, a good lubricant and cooling agent is lard... Before drilling, the rotary drill is immersed in a piece of bacon, 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 soapy water.

When drilling through with a high feed, a burr (burr) is formed at the exit of the hole, to which the drill clings with its lateral incisors. As a result, a sharp blockage of the drill and its fracture or chisel breakage can occur, and even at this moment the drill becomes especially intensely blunt. Such stops have a negative effect on the condition of the drill. To avoid burr formation, you need to finish drilling holes in the metal at a low feed. It is also advisable to put under the drilled part wooden block which prevents the formation of burrs. 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 firmly pressed against the drill exit.

Most often, it is necessary to drill steel, but often other metals have to be drilled, which have their own drilling characteristics. Aluminum, for example, envelops the drill, making it harder to penetrate and widen the resulting hole. If you want to drill a precise hole in aluminum (for example, for a thread), it is imperative to use coolant and often remove the drill from the hole to clean it. Conventional gray cast iron drills relatively easily and requires no coolant or lubricant. But drilling in cast iron can be a surprise. There are ductile cast irons that need to be drilled with a carbide drill. White cast iron, the main structural constituent of which is cementite, is very hard and requires a high strength drill.

Large 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, it is better to drill a hole with a diameter of 12 mm in two or three steps - successively with drills of 5, 10 and 12 mm.

Dull drills must be sharpened in a timely manner. It is best to do this with a sharpener, but you can do without it. In this case, you need to pay attention to the symmetry of the drill tip. If the sharpened edges do not converge exactly 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 nose angle (angle between cutting edges) is 118 °. For drilling in aluminum, the optimum angle is 130-140 °, soft bronze and red copper 125-130 °. However, all of these metals can be drilled with a standard angle drill. Read more about sharpening a drill.

When drilling, it is necessary to maintain the verticality of the drill relative to the metal surface (if you do not need 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 diameter pipes. It is quite difficult to maintain the perpendicularity of the drill by eye, so you can use homemade or purchased jigs for drilling or guides that ensure the perpendicularity of the drill.

Jigs are also required for drilling two or more holes in mating parts. The best way ensuring the alignment of the holes is by drilling them together. When drilling holes for rivets, the drilling assembly is mandatory requirement... Once you have drilled the first hole, you can use it to bolt the parts together so that you can drill the rest of the holes without the fear that the parts will move relative to each other. If it is impossible or inconvenient to drill the mating parts in the assembly, then the jig or guide must be used. You should be aware that no matter how accurately the mating holes are marked and pored, they will not coincide absolutely exactly, since when drilling even a punched hole, the drill will go a little to the side.

When using the content of this site, you need to put active links to this site, visible to users and search robots.

Drilling large holes is no problem with the right tool. For example, such work may be necessary to secure a channel or metal corner. The easiest way is to use an electric drill, but it takes a lot of effort to get a hole with a diameter of, for example, 15 mm. To drill a large hole in metal, special tools and core drilling technology are used.

Features of creation

When drilling, it must be borne in mind that a castellated or stepped taper nozzle must be selected so that it has a smaller diameter than the hole to be created.

Using various instruments it is also necessary to take into account their features. For example, when reaming with tapered products, smooth edges are obtained.

Drill attachments

There are several attachments for drills that make the process easier and make big hole even:

• Drilling jig. Such a device is a body in which there are several drill guide sleeves. different diameters... The material used to create the bushings is harder than drills, so you don't have to worry about the tool deflecting to the side while drilling and expanding the hole.
• Drill guide. Such a product allows you to fix the tool in such a way that during drilling it does not deviate to the side. In the absence of such a product, the tool may move to the side, which will lead to the creation of an uneven edge. It can also be fixed at an angle. But when drilling metal products this is usually not required.
• Drill stand. A similar hand-made product may be inexpensive replacement drilling machine, as it allows you to more comfortably carry out the work. The fixed tool, when using the stand, moves along the bar with the help of a lever. At the same time, displacement is completely excluded, since the workpiece to be drilled is reliably held due to the presence of a clamp.

Using these products, you can greatly facilitate the process of drilling metal products.

Deep hole feature

To drill a deep hole in metal, it is best to use lathe... During this process, it is imperative to cool. In this case, the chips must be forcibly removed. Periodically, the tool is removed from the workpiece to remove chips.

When working without specialized tools, do not recessed the nozzle more than 2/3 of its length. For cooling during operation, you must use water. If the work is done in several approaches, it is not allowed to change the angle.

Feature of large diameter holes

This procedure is more complex than deep drilling. Cutting work is carried out either using a crown or using a cone drill. Metal crowns are similar to concrete and drywall products. The only difference is in the material used to create the cutting edge.

Also, drilling can be performed with standard products in several stages. For this, a small diameter nozzle is used first. The larger tool is then selected.

Most in a convenient way is the use of tapered drills. Such devices allow you to drill a hole in one go big size... To do this, the tool is simply sunk into the material.

Hassle-free drilling

During work, you can use a small section nozzle, as well as a used grinding wheel for the grinder. It is important to remember that it must have a smaller diameter than the hole to be created.

Before carrying out work on the workpiece, a circle is marked for the hole, and the second circle will be less than the first by a distance equal to the diameter of the drill used. After that, 2 holes are marked in opposite places of the circle. It is necessary to step back 3 mm from them and mark the places for drilling. Thus, drilling occurs along the entire drawn circle. If necessary, some parts will have to be processed with a chisel. This will create jagged edges that will need to be sharpened. It is important to ensure that during the work there is no increase in the circumference, that is, do not expand the planned diameter.

Cone drill

The described types of drills are made from tool steel. The shanks of such products can be hexagonal and cylindrical. The cutting edge removes all burrs, so the edge is smooth. At the end of the drill head, there is a sharpened point that allows pre-drilling into the material.

Using such products you can:

• create cuts with a diameter of up to 30 mm;
• forget about uneven edges;
• carry out boring of various diameters without changing the nozzle.

With the step drills, you can create cuts of various diameters in sheet steel up to 4 mm thick. In contrast to a simple cone drill, when using such products, the drilled diameter is fixed.

The disadvantages include:

• the need to use a tool with low speed and high torque;
• sensitivity even to slight distortions.

Despite these disadvantages, this nozzle allows you to conveniently work with metal plates, quickly drilling a circle of the required diameter.

Metal crown

Metal processing is a complex process, therefore such work is usually performed using specialized equipment. To perform work in a domestic environment, you can use core drills.

Such products allow you to make the edges round and centered. In this case, a standard drill is used for drilling. Products consist of several parts:

• crown;
• centering nozzle;
• product shank;
• screws that are needed for fastening.

When using a core drill, the work speed is increased up to 10 times. Also, the advantages include the ability to accurately drill in the range from 1.2 to 15 cm.

At the same time, there is no need to center during drilling. It is also worth noting that such drills, in comparison with spiral drills, have a higher wear resistance.

Before starting work, a center drill is installed in the center of the circle, after which drilling is carried out. After that, the drill is retracted and the work is carried out with a crown.

Hole press

One of the most common methods is punching with a special press. It goes like this:

1. First, the workpiece is placed on the press table and gripped by several clamps.
2. Then the metal is moved under the punching tool. At this stage, additional fastening of the material takes place with the help of a clamping ring.
3. On the last stage and there is a punching through with a punch.

The revolver can have several nozzles of different diameters, which allows you to quickly create holes of different diameters. Such equipment is usually not used for working with metal in a domestic environment.

If you plan to do the work at home, you should choose a universal tool. This will allow you to easily process metal without worrying about purchasing additional parts. The presented video will acquaint you with the process technology in detail.