How to drill metal. What and how to drill deep and large holes in metal parts. Causes of drill breakage

The work of drilling holes in metal, depending on the type of holes and the properties of the metal, can be performed with different tools and using different techniques. We want to tell you about drilling methods, tools, as well as safety precautions when performing these works.

Drilling holes in metal may be needed when repairing engineering systems, household appliances, cars, creating structures from sheet and profile steel, designing crafts from aluminum and copper, in the manufacture of circuit boards for radio equipment, and in many other cases. It is important to understand what kind of tool is needed for each type of work so that the holes are the right diameter and in a strictly intended place, and what safety measures will help to avoid injury.

Tools, fixtures, drills

The main tools for drilling are manual and electric drills, and, if possible, drilling machines. The working body of these mechanisms - the drill - can have a different shape.

There are drills:

• spiral (most common);
• screw;
• crowns;
• conical;
• feathers, etc.

The production of drills of various designs is standardized by numerous GOSTs. Drills up to Ø 2 mm are not marked, up to Ø 3 mm - the section and steel grade are indicated on the shank, larger diameters may contain additional information. To obtain a hole of a certain diameter, you need to take a drill a few tenths of a millimeter smaller. The better the drill is sharpened, the smaller the difference between these diameters.

Drills differ not only in diameter, but also in length - short, elongated and long are produced. Important information is the ultimate hardness of the metal being processed. The shank of the drills can be cylindrical and conical, which should be borne in mind when selecting a drill chuck or adapter sleeve.

1. Drill with a cylindrical shank. 2. Tapered shank drill. 3. Drill with a sword for carving. 4. Center drill. 5. Drill with two diameters. 6. Center drill. 7. Conical drill. 8. Conical multi-stage drill

For some work and materials, special sharpening is required. The harder the metal being processed, the sharper the edge must be sharpened. For thin sheet metal, a conventional twist drill may not be suitable, you will need a tool with a special sharpening. Detailed recommendations for various types of drills and processed metals (thickness, hardness, hole type) are quite extensive, and we will not consider them in this article.

Various types of drill sharpening. 1. For hard steel. 2. For stainless steel. 3. For copper and copper alloys. 4. For aluminum and aluminum alloys. 5. For cast iron. 6. Bakelite

1. Standard sharpening. 2. Free sharpening. 3. Diluted sharpening. 4. Heavy sharpening. 5. Separate sharpening

To fix parts before drilling, a vice, stops, conductors, corners, clamps with bolts and other devices are used. This is not only a safety requirement, it is actually more convenient, and the holes are of better quality.

To chamfer and process the surface of the channel, they use a countersink of a cylindrical or conical shape, and to mark a point for drilling and so that the drill does not “jump off” - a hammer and a center punch.

Advice! The best drills are still considered to be those produced in the USSR - exact adherence to GOST in geometry and metal composition. German Ruko with titanium coating are also good, as well as drills from Bosch - proven quality. Good reviews about Haisser products are powerful, as a rule, with a large diameter. The Zubr drills, especially the Cobalt series, proved to be worthy.

Drilling modes

It is very important to correctly fix and guide the drill, as well as select the cutting mode.

When making holes in metal by drilling, important factors are the number of revolutions of the drill and the feed force applied to the drill, directed along its axis, providing the penetration of the drill at one revolution (mm / rev). When working with different metals and drills, different cutting conditions are recommended, and the harder the metal being processed and the larger the diameter of the drill, the lower the recommended cutting speed. An indicator of the correct mode is a beautiful, long chip.

Use the tables to choose the right mode and not dull the drill prematurely.

Table 2. Correction factors

Table 3. Revolutions and feeds for various drill diameters and drilling in carbon steel

Types of holes in metal and methods for drilling them

Types of holes:

• deaf;
• through;
• half (incomplete);
• deep;
• large diameter;
• for internal thread.

Threaded holes require the determination of diameters with tolerances established in GOST 16093-2004. For common hardware, the calculation is given in table 5.

Table 5. The ratio of metric and inch threads, as well as the selection of the hole size for drilling

through holes

Through holes penetrate the workpiece completely, forming a passage in it. A feature of the process is the protection of the surface of the workbench or tabletop from the exit of the drill beyond the workpiece, which can damage the drill itself, as well as provide the workpiece with a “burr” - a hart. To avoid this, use the following methods:

• use a workbench with a hole;
• put a gasket made of wood or a “sandwich” under the part - wood + metal + wood;
• put a metal bar under the part with a hole for the free passage of the drill;
• reduce the feed rate at the last stage.

The latter method is mandatory when drilling holes "in place" so as not to damage closely spaced surfaces or parts.

Holes in thin sheet metal are cut with spatula drills, because the twist drill will damage the edges of the workpiece.

blind holes

Such holes are made to a certain depth and do not penetrate the workpiece through and through. There are two ways to measure depth:

• limiting the length of the drill with a sleeve stop;
• limiting the length of the drill with an adjustable stop chuck;
• using a ruler fixed on the machine;
• a combination of methods.

Some machines are equipped with an automatic feed to a given depth, after which the mechanism stops. During the drilling process, it may be necessary to stop the work several times to remove the chips.

Holes of complex shape

Holes located on the edge of the workpiece (half) can be made by connecting two workpieces or a workpiece and a gasket with faces and clamping with a vise and drilling a full hole. The gasket must be made of the same material as the workpiece being processed, otherwise the drill will “leave” in the direction of least resistance.

A through hole in the corner (shaped rolled metal) is performed by fixing the workpiece in a vice and using a wooden gasket.

It is more difficult to drill a cylindrical workpiece tangentially. The process is divided into two operations: preparation of a platform perpendicular to the hole (milling, countersinking) and drilling itself. Drilling holes in angled surfaces also begins with site preparation, after which a wooden spacer is inserted between the planes, forming a triangle, and a hole is drilled through the corner.

Hollow parts are drilled, filling the cavity with a cork made of wood.

Stepped holes are produced using two techniques:

1. Reaming. The hole is drilled to the full depth with a drill of the smallest diameter, after which it is drilled to a given depth with drills with diameters from smaller to larger. The advantage of the method is a well-centered hole.
2. Reducing the diameter. A hole of maximum diameter is drilled to a given depth, then the drills are changed with a successive decrease in diameter and a hole deepening. With this method, it is easier to control the depth of each step.

1. Drilling a hole. 2. Diameter reduction

Large diameter holes, annular drilling

Obtaining holes of large diameter in massive workpieces, up to 5-6 mm thick, is a laborious and costly business. Relatively small diameters - up to 30 mm (maximum 40 mm) can be obtained using cone, and preferably step-cone drills. For holes with a larger diameter (up to 100 mm), hollow bi-metal hole saws or hole saws with carbide teeth with a center drill will be required. Moreover, the craftsmen traditionally recommend Bosch in this case, especially on hard metal, such as steel.

Such annular drilling is less energy-intensive, but may be more financially costly. In addition to drills, the power of the drill and the ability to work at the lowest speeds are important. Moreover, the thicker the metal, the more you want to make a hole on the machine, and with a large number of holes in a sheet with a thickness of more than 12 mm, it is better to immediately look for such an opportunity.

In a thin-sheet blank, a large-diameter hole is obtained using narrow-toothed crowns or a milling cutter mounted on a grinder, but the edges in the latter case leave much to be desired.

Deep holes, coolant

Sometimes a deep hole is required. In theory, this is a hole whose length is five times the diameter. In practice, deep drilling is called, requiring forced periodic removal of chips and the use of coolants (cutting fluids).

In drilling, coolants are needed primarily to reduce the temperature of the drill and workpiece, which are heated by friction. Therefore, when making holes in copper, which has a high thermal conductivity and is itself capable of removing heat, coolant can be omitted. Cast iron is drilled relatively easily and without lubrication (except for high-strength ones).

In production, industrial oils, synthetic emulsions, emulsols and some hydrocarbons are used as coolants. In home workshops you can use:

• technical vaseline, castor oil - for mild steels;
• laundry soap - for aluminum alloys of the D16T type;
• a mixture of kerosene with castor oil - for duralumin;
• soapy water - for aluminum;
• turpentine diluted with alcohol - for silumin.

The universal coolant can be prepared independently. To do this, you need to dissolve 200 g of soap in a bucket of water, add 5 tablespoons of machine oil, you can use it, and boil the solution until a soapy homogeneous emulsion is obtained. Some masters use lard to reduce friction.

Deep holes can be made by solid and annular drilling, and in the latter case, the central rod formed by the rotation of the crown is broken out not entirely, but in parts, weakening it with additional holes of small diameter.

Solid drilling is performed in a well-fixed workpiece with a twist drill, through the channels of which coolant is supplied. Periodically, without stopping the rotation of the drill, it is necessary to remove it and clean the cavity from chips. The work with a twist drill is carried out in stages: first, a short hole is taken and a hole is drilled, which is then deepened with a drill of the appropriate size. With a significant depth of the hole, it is advisable to use guide bushings.

With regular drilling of deep holes, it can be recommended to purchase a special machine with automatic coolant supply to the drill and precise centering.

Drilling by marking, template and jig

You can drill holes according to the markings made or without it - using a template or a jig.

Marking is done with a punch. A hammer blow marks a place for the tip of the drill. A felt-tip pen can also mark a place, but a hole is also needed so that the tip does not move from the intended point. The work is carried out in two stages: preliminary drilling, hole control, final drilling. If the drill "left" from the intended center, notches (grooves) are made with a narrow chisel that guide the tip to a given place.

To determine the center of a cylindrical workpiece, a square piece of tin is used, bent at 90 ° so that the height of one shoulder is approximately one radius. Applying a corner from different sides of the workpiece, draw a pencil along the edge. As a result, you have an area around the center. You can find the center by the theorem - the intersection of perpendiculars from two chords.

A template is needed when making a series of parts of the same type with several holes. It is convenient to use it for a pack of thin-sheet blanks connected with a clamp. This way you can get several drilled blanks at the same time. Instead of a template, a drawing or diagram is sometimes used, for example, in the manufacture of parts for radio equipment.

The conductor is used when the accuracy of maintaining the distances between the holes and the strict perpendicularity of the channel are very important. When drilling deep holes or when working with thin-walled tubes, in addition to the conductor, guides can be used to fix the position of the drill relative to the metal surface.

When working with a power tool, it is important to remember human safety and prevent premature wear of the tool and possible marriage. In this regard, we have collected some useful tips:

1. Before work, you need to check the fastening of all elements.
2. Clothing when working on a machine or with an electric drill should not be with elements that can fall under the action of rotating parts. Protect your eyes from chips with goggles.
3. The drill, when approaching the surface of the metal, must already rotate, otherwise it will quickly become dull.
4. It is necessary to remove the drill from the hole without turning off the drill, reducing the speed if possible.
5. If the drill does not go deep into the metal, then its hardness is lower than that of the workpiece. Increased hardness in steel can be detected by running a file over the sample - the absence of traces indicates increased hardness. In this case, the drill must be selected from a carbide with additives and work at low speeds with a small feed.
6. If a small diameter drill does not fit well in the chuck, wind a few turns of brass wire around its shank, increasing the diameter to grip.
7. If the surface of the workpiece is polished, put a felt washer on the drill to ensure that it does not scratch even when it comes into contact with the drill chuck. When fastening workpieces made of polished or chrome-plated steel, use spacers made of fabric or leather.
8. When making deep holes, a rectangular piece of foam placed on a drill can serve as a measuring instrument and at the same time, while rotating, blow off small chips.

Hole drilling is a type of metal processing by means of rotating devices by cutting. This operation is divided into deep drilling and conventional. In the first option, the depth of the hole is more than 10 cm or has a size of more than 5 available diameters (d * 5). With drills, it is possible to achieve recesses of different depths and diameters (with several cross-sectional faces).

Drilling holes in metal is possible in one of the following ways:

1. The workpiece is rotated and at the same time the longitudinal feed of the non-rotating drilling tool is performed.
2. The workpiece does not rotate, it assumes a fixed position.
3. Simultaneous movement around its axis of both the mechanism and the part.

In practice, these technologies are quite in demand. The procedure for forming deep holes is in great demand in such areas as the manufacture of pipes, metallurgy, aerospace and oil and gas industries, the production of heat exchanger plates, etc. Deep holes often have to be made on the following parts: axles, sleeves, bandages, shafts, rotors, bushings, cylinders , metal shells, etc.

Deep Hole Drilling: Classification

1. According to the type of removal of the drilled content (chips), they distinguish: annular and continuous procedures. In the second method, the drilled content is removed like chip particles, in the first one, the annular plane is partially removed like a rod, and the other part is shaving.
2. According to the cutting method, technologies are distinguished:

Single bar (STS). This method is optimal for the manufacture of blanks in a high-performance or mass production process. The problem here is that you have to use the oil receiver with a variety of supply hoses while rotating the part. This system is recognized as the most effective in the formation of holes of high quality.

Ejector. Deep processing option with medium quality parameters. Processing is carried out on lathes with many complex functions. The system involves the use of an additional mobile or installed pumping station. This method allows you to get holes with a diameter of 2 to 6 cm to a depth of 120 cm, including intermittent.

Rifle (tubular-blade) drills with the supply of a cooling and lubricating agent from the inside. This option is suitable for small enterprises in which it is planned to obtain holes of small diameter under the conditions of technology.

Drills with a single cutter are easily built into machines with a universal principle of operation. The cutter is made of hard alloys and has a V-shaped groove along the entire length of the rod. The refractive angle of the latter can reach 110-1200º. The recommended diameter for drilling is 3.5-4.0 cm, length is d * 50. This method does not provide for deployment and reaming operations.

Automatic process control allows you to select: deep impact with an automated change of one or many regime parameters (lubrication supply, rotation speed, etc.).

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Characteristics of the deep drilling process

In deep processing, the basic principles of the technological process are observed.

Initially, the rotational speed of the drilling part of the equipment or the maximum possible cutting speed (drill feed) is selected.

They monitor the provision of normal chip crushing, the removal of the contents from the recesses completely.

An important nuance at the time of excision of waste is the safety of the cutter of the tool. In this part, the drill should not have damage, as well as burrs and other flaws. Another key criterion for effective metal surface treatment is the correct supply of coolant and lubricant.

Since the parts are drilled, accompanied by the supply of coolant and lubricant with a certain pressure and with a given flow rate, the operation of pumping devices is introduced into the system - oil pumps or pumps for pumping viscous substances.

The power of the system is selected based on the consumption of fluid and the required pressure to supply the lubricant.

Liquid supply is an indispensable point of technology:

1. The correct removal of chips from the working area through the output channels is performed.
2. The force of friction between the contacting elements is reduced.
3. The removal of excess heat generated during the procedure of long drilling is carried out, while the safety of the drill is ensured.
4. Additional processing of the excavation is carried out.

Hello! About how to drill metal with a drill, if you wish, you can write a very large article. But I see two main problems here:

• inability to precisely drill in the place where a hole is required
• quick blunting of drills

Usually inexperienced users face such problems. Experienced men know what to do in such cases. Well, considering myself experienced, I will take the liberty of telling you how to deal with these problems. Well, I will also give a few tips that will also come in handy.

How to drill in the right place?

If you think a little about this question, then the answer should visit your head even without a hint. Well, it seems so to me at least. But if you don't feel like thinking, then read on.

For this case, you need a core. This is a tool made of durable steel, having a cylindrical shape and a point at the end.

We put the tip to the desired drilling site and hit the roll on the other side with a hammer several times.

Now, when you are centered, put a drill on the surface of the roughness and start drilling - the tip will not run away anywhere.

How not to dull drills?

Drill bits for metal become blunt if they get too hot during operation, due to which they lose their strength. Heating is due to friction. Moreover, the faster it spins, the more it heats up.

Hence the obvious rule - you need to drill at a low speed drill. They should be no more than 1000 per minute. But who will measure this at work? Therefore, just do not press the start button to the full. The correct speed can be estimated as follows: the eye should see the rotation of the drill. That is, the grooves on it should not merge into one for vision.

When working with thick workpieces, additional cooling is indispensable. It is provided by special lubricants or pastes that are added to the drilling site, or the drill is dipped into them. In addition, they not only cool, but also lubricate the tip, thereby reducing friction.

At home, there is no need to have special lubricants and pastes. You can get by with regular engine oil.

So, use a core, drill at low speeds, and add grease or oil, and then this thing will seem like a cakewalk to you.

Well, a few more tips on this topic.

Drill types

For drilling, take only drills for metal (and not for wood, for example). They have their own sharpening and are made of certain types of steel. The most common are marked P6M5 - this is high-speed steel, which foreign manufacturers label as HSS.

To give additional strength to the above drills, a titanium nitride coating is applied. Because of what they are yellow.

There are also stronger P18s used for hard steels respectively.

Also, cobalt can be added to increase strength, and then the P6M5K5 marking is obtained.

Well, the most durable are drills with a carbide tip. They are used for drilling alloy steels. It will also take ordinary steel, but it will be somewhat prudent to buy it only for this, since the price for them is quite high, while it is solid, but still blunt. But it will be difficult to sharpen it later, since this requires a diamond blade, which is also not very cheap, and you can’t buy it everywhere.

Drilling thick workpieces

If the workpiece has a thickness of more than 5 mm, and you need a hole of more than 8 mm, then it is better to first make a hole with a thin drill, and only then work with a thick one.

Working with some types of metal

• When drilling thick aluminum workpieces, chips often clog the bores of the drill, making it harder to turn. Therefore, when working with such material, take the drill out of the recess more often and remove the chips. Oh, and don't forget to drizzle with plenty of oil.
• If you need to drill black cast iron, then for this you do not need to add any lubricating and cooling agents, since it is drilled very well even in the dry
• Unlike black cast iron, white cast iron has increased strength, which means that strong drills and lubrication will be required for its processing.

These are the basic rules for drilling metal with a drill. I hope I managed to fill this gap in your knowledge. Good luck with your homework and see you soon!

Why do some people drill metal quickly and without much difficulty, while others resemble an epic, accompanied by broken and blunt drills?

Drill selection

Drilling of metal parts is usually performed using twist drills with two cutting edges in the working part and two helical grooves for chip removal.

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.

Titanium-coated drills have higher strength indicators. They differ from the rest of the tool with a yellow coating.

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

Lubrication and cooling

In the process of drilling metal, the drill under the influence of friction 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 simultaneous lubrication and cooling of the drill, there are special cutting fluids and pasty formulations.

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

At home, in the absence of special means for lubrication and cooling, you can use machine oil; 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 with a core and a hammer.

This will avoid going to the side of the drill at the initial stage of its cutting into the metal.

Under the metal blank, place a piece of board of the appropriate size. The part will slip less and the exit hole edges 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 drilling stand, spacer or guide greatly facilitates the work.

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

The indicator of the correctness of the choice of force for pressing is the chips issued by the drill.

Small crumbs indicate that the pressure needs to be increased, thin chips indicate normal feed, while thick spiral chips indicate the need to reduce the force on the drill.

Beginning craftsmen make the most mistakes when choosing the speed of drilling metal, setting the drill's rotation speed too high. As a result, the drill overheats, quickly becomes dull 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 up to 400 rpm for drills with a thickness of 13 mm or more.

When making a through hole, pay special attention to the final phase of drilling.

The drill can catch on the side cutters with a burr formed at the exit of the hole, which is fraught with sudden blocking of the drill or even its fracture.

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

If you need to make a hole with a large diameter, 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 screw a drill of the desired diameter in the chuck of an electric drill.

This approach will provide more efficient and faster cutting of metal, reducing the likelihood of misalignment.

Good luck to you! May you succeed!

Drilling large holes is not a problem if you use the right tool. For example, such work may be necessary to secure a channel or a 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 diameter hole in metal, special tools and core drilling technology are used.

Creation features

During drilling, it must be taken into account that the crown or stepped cone nozzle must be selected in such a way that it has a smaller diameter than the hole being created.

When using different tools, it is also necessary to take into account their features. For example, when reaming with conical products, even edges are obtained.

Drill attachments

There are several accessories for drills that make it easier to process and make a large hole even:

• Drilling guide. Such a device is a housing in which there are several guide bushings for drills of different diameters. The material used to make the bushings is harder than drill bits, so you don't have to worry about the tool tipping to the side while drilling and widening the hole.
• Drill guide. Such a product allows you to fix the tool so 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. Such a hand-made product can be an inexpensive replacement for a drilling machine, as it allows you to more comfortably carry out work. The fixed tool, when using the rack, moves along the bar with the help of a lever. In this case, displacement is completely excluded, since the workpiece to be drilled is securely held due to the presence of a clamp.

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

Feature of deep holes

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

When working without specialized devices, you should not sink the nozzle by more than 2/3 of its length. Water must be used for cooling during operation. If the work is done in several approaches, a change in the angle is not allowed.

Features 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. Crowns for metal are similar to products for concrete and drywall. The difference lies only in the material used to create the cutting edge.

Also, drilling can be done with standard products in several stages. To do this, first use a small diameter nozzle. Then a larger instrument is selected.

The most convenient way is to use cone drills. Such devices allow you to drill a large hole in one go. To do this, the tool is simply recessed into the material.

Drilling without the hassle

During operation, you can use a nozzle of a small section, as well as a used grinding wheel for a grinder. It is important to remember that it must have a smaller diameter than the hole being 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. From them it is necessary to retreat 3 mm and outline the places for drilling. Thus, drilling occurs along the entire drawn circle. If necessary, some areas will have to be processed with a chisel. As a result, jagged edges will be created, which will then need to be turned. It is important to ensure that during the work there is no increase in the circumference, i.e., do not expand the planned diameter.

Cone drill

The described types of drills are made from tool steel. 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 tip that allows pre-drilling of the material.

Using these products you can:

• to 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 step drills, cuts of various diameters can be made in sheet steel up to 4 mm thick. Unlike 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 to even small distortions.

Despite these shortcomings, this nozzle allows you to conveniently work with metal plates, quickly drilling circles of the desired diameter.

Crown for metal

Metal processing is a complex process, so such work is usually done using specialized equipment. To work at home, 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 needed for fixing.

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

Thus during drilling it is not necessary to make centering. It is also worth noting that such drills have a higher wear resistance compared to spiral drills.

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 by the crown.

Hole press

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

1. First, the workpiece is placed on the press table and gripped by several clamps.
2. The metal is then moved under the punching tool. At this stage, there is an additional fixation of the material with the help of a clamping ring.
3. At the last stage, penetration occurs with the help of 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 the work is planned to be done 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 technology of the process in detail.