How to make a slot in metal

Making a hole in hardened steel without drilling

In this simple way you can make not only a round hole in hardened steel, but also a hole of any other shape without any extra effort. The chemical method will help you out and make the task easier. The method does not require expensive chemicals; all ingredients can be found in any household.

Will need

I offer a simple method for making holes in high-speed steel. To work you will need:

• any product made of high-speed steel;
• marker;
• nail polish;
• nail polish remover (can be replaced with white spirit or acetone. I chose the remover only because of the pleasant smell, and it’s the same acetone);
• cotton wool;
• empty plastic container (bottle);
• salt;
• knife;
• a homemade device made from a charger and two nails.

Making a hole in metal without a drill

Apply nail polish remover to the cotton wool and degrease the surface of our workpiece.

Apply varnish to the desired area. The varnish must be applied in a thick layer on both sides. Don't forget to coat the ends thoroughly. Leave the workpiece for 10-15 minutes to allow the varnish to dry.

On the dry surface, with a marker on both sides of the workpiece, I mark the place for the hole. I choose the location arbitrarily, now I need to show how to make a hole using this method. For example, you need to install a regular factory rivet. The diameter of the hole should be slightly smaller than the size of the rivet.

Then use a knife to remove the varnish inside the hole outline. Do this on both sides.

Pour water into a container and add 3 tablespoons of salt. The height of the water in the container should be 10 mm less than the height of the varnished area of ​​the workpiece.

I take a device made from a hair clipper charger and two nails. The nails will serve as electrodes - I connected them to one contact. The other contact is simply bare, stripped wire. I use a 12V charger, but a regular cell phone charger will do the job.

The stripped wire should be positive, the electrodes should be negative. We attach the positive wire to our workpiece using a clothespin. Then we lower the nails into the water.

You can make slits in the container to fix the position of the nails. Plugging the charger into a power outlet. After switching on, the water around the electrode nails begins to bubble, and the cleaned hole mark turns black.

Note: to check the polarity of the wires, you must connect the charger. If water starts to bubble around the nails, it means it's a minus and you connected correctly.

The appearance of bubbles in the water around the workpiece indicates that the minus is connected to it and the wires need to be reconnected.

The negative must always be connected to the electrodes, the positive to the workpiece being etched!
Leave the container for one hour, 30 minutes after the start of the process you need to change the water. I turn off the charger and take out the workpiece.

A through hole appeared in the intended location.
In order to make the hole diameter larger, the process can be continued. Or file uneven edges with a file. This is how you can make the desired hole in a workpiece by etching high-speed steel using the most ordinary objects.

Watch the video

Source: https://coollifehack.ru/kak-sdelat-otverstie-v-zakalennoj-st/

What and how to drill deep and large holes in metal parts

Drilling large holes is not a problem if you choose 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 getting a hole with a diameter of, for example, 15 mm requires a lot of effort. To drill a large diameter hole in metal, special devices and core drilling technology are used.

Features of creation

When 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 drilling with conical products, smooth edges are obtained.

Drill accessories

There are several accessories for drills that can make the process easier and make a large hole smooth:

• Drilling jig. This device is a housing in which there are several guide bushings for drills of different diameters. The material used to create the bushings is harder than drill bits, so you don't have to worry about the tool moving to the side while drilling and widening the hole.
• Drill guide. This product allows you to fix the tool in such a way that it does not deviate to the side during drilling. If such a product is not available, the tool may move to the side, resulting in an uneven edge. It can also be mounted at an angle. But when drilling metal products, this is usually not required.
• Drill stand. A DIY product like this can be an inexpensive replacement for a drilling machine, as it allows you to carry out work more comfortably. When using a stand, a fixed tool moves along the bar using a lever. In this case, displacement is completely eliminated, since the workpiece being 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. Cooling must be done during this process. In this case, the chips must be forcibly removed. Periodically, the tool is removed from the workpiece to remove chips.

When working without specialized devices, you should not recess the nozzle more than 2/3 of its length. Water must be used for cooling during operation. If the work is done in several approaches, changing 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 only difference is the material used to create the cutting edge.

Drilling can also be carried out with standard products in several stages. To do this, first use a nozzle of small diameter. Then a larger tool 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.

Hassle-free drilling

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

Before carrying out work, a circle for the hole is marked on the workpiece, and the second circle will be smaller than the first by a distance equal to the diameter of the drill used. After this, 2 holes are marked in opposite places of the circle. It is necessary to retreat 3 mm from them and mark the places for drilling.

Thus, drilling occurs along the entire drawn circle. If additional work is necessary, some areas will have to be processed with a chisel. This will create jagged edges that will then need to be filed down. It is important to ensure that during work the circumference does not increase, i.e.

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 or cylindrical. The cutting edge removes all burrs, so the edge is smooth. The end of the drill head has a sharpened point that allows pre-drilling of the material.

Using these products you can:

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

Thanks to step drills, you can create cuts of various diameters 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 tools with low speeds and high torque;
• sensitivity even to small distortions.

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

Metal crown

Metal processing is a complex process, so such work is usually carried out using specialized equipment. To carry out 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. The products consist of several parts:

• crown;
• centering attachment;
• product shank;
• screws that are necessary for fastening.

When using a core drill, the speed of work increases up to 10 times. Another advantage is the ability to accurately drill in the range from 1.2 to 15 cm.

In this case, there is no need to perform alignment during drilling. It is also worth noting that such drills have higher wear resistance compared to twist drills.

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

Hole press

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

1. First, the workpiece is placed on the press table and grabbed by several clamps.
2. The metal is then moved under the punching tool. At this stage, additional fastening of the material occurs using a clamping ring.
3. At the last stage, penetration occurs using 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 domestic conditions.

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 video presented will introduce you in detail to the technology of the process.

Source: https://oxmetall.ru/sverlenie/glubokie-i-bolshie-otverstiya

How to drill metal. Technology for drilling holes in metal

Why do some people drill metal quickly and without much difficulty, while for others it resembles an epic, accompanied by broken and dull drills?

Drill selection

Drilling of metal parts is usually performed using twist drills that have two cutting edges in the working part and two helical grooves for removing chips.

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

Drills coated with titanium have higher strength values. They differ from the rest of the instrument by their yellow coating.

In addition to spiral drills, there are also stepped drills, which have a herringbone shape in the 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

During the process of drilling metal, the drill can become very hot under the influence of frictional forces. 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 reducing the friction force. For simultaneous lubrication and cooling of the drill, there are special cutting fluids and paste-like compositions.

Before starting work, liquid lubricant is applied to the drill using a brush or introduced into the hole being drilled with an oil can; 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 in ordinary gray cast iron is done “dry”.

Drilling technology

Before starting drilling, be sure to make a small depression in the center of the future hole using a core and a hammer.

This will allow you to avoid moving towards the drill at the initial stage of cutting into the metal.

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

Hold the drill so that the drill bit is positioned strictly 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 noticeable. As the drill cuts into the metal, the pressure can be increased slightly.

An indicator of the correct choice of pressing force is the chips produced by the drill.

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

The biggest mistakes novice craftsmen make when choosing the speed of drilling metal are by setting the rotation speed of the drill 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. As the drill diameter increases, the drill speed should decrease proportionally, reaching 400 rpm for drills with a thickness of 13 mm or more.

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

The drill can get caught by the lateral incisors on the burr formed at the exit of the hole, which can lead to sudden blocking of the drill or even its fracture.

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

If it is necessary 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 out with an 8 mm drill and only after that attach a drill of the required 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 everything work out for you!

Source: https://goodmaster.com.ua/dom-i-kvartira/kak-sverlit-metall.html

What you need to know about drilling holes in metal

You can secure a metal sheet or part using a variety of fasteners. However, you need to make holes for them. Drilling holes in metal requires a person to use special tools. To carry out the work without difficulty, you need to be able to choose equipment and work with workpieces of different sizes.

Drilling holes in metal

Equipment types

Drilling begins with preparing tools for work. You can make holes using a screwdriver, drill or a special drilling machine.

To make a hole, you need to select the appropriate equipment. For metal workpieces, you need to choose specialized equipment that is suitable specifically for this material. This is due to the fact that equipment for wood, concrete or ceramic tiles have different sharpening and shape. Tooling for metal products is marked with the letters HSS.

The working part of the tool is coated with titanium nitride coating, which increases their strength and wear resistance. For hard steels, a different tooling is used, which is designated P18. The strength of the tool increases when cobalt is added to its composition. An example of marking is P6M5K5.

To drill alloy steel, drills with a tip made of carbide are used. With their help, you can drill any metal workpieces, however, due to the high price, this is not cost-effective.

When the hole is made, you can select a drill for the thread. Its diameter will depend on the previously used equipment. To make holes of different diameters in thin metal sheets, you can use cone drills.

Is it possible to drill with a drill in concrete?

Situations often arise when it is difficult to find a tool for drilling metal products at a construction site, but there is equipment for working with concrete. You cannot make holes of large diameter or in thick metal sheets with concrete drills. Otherwise, you may break the equipment or damage the surface being processed.

How to drill with a step drill?

On sale you can find stepped structures for creating holes in metal of various diameters. Several drills of different diameters are fixed on one axis. They are designed to create holes of various sizes in thin sheet metal. When working, do not rush or put too much pressure on the drill handle.

Is it possible to drill with a Pobedit drill?

Any master of finishing work will tell you that drilling metal with Pobedit equipment is unacceptable. Pobedite drills are designed for hard and, at the same time, brittle materials. These include natural stone, brick, concrete. When it hits metal, the drill will hit the surface and damage it, but there will be no hole.

How to drill large diameter holes?

Drilling large holes in metal requires the use of appropriate equipment. You can do the work in several ways:

1. Crown for metal surfaces. It is a circle of the required diameter with sharpened edges. There is a drill in the center that pierces the metal. Next, at low engine speeds, the bit makes a hole of the selected diameter. During work, it is necessary to use forced cooling of the sharp edges of the crown and the surface being treated.
2. Multi-stage operation. This implies the use of several metal drills of different diameters. Work begins with equipment of the smallest diameter and increases as drilling progresses.
3. Cone-shaped equipment (stepped). Designed for working with thin sheet metal.

Builders recommend using crowns. However, when working with them, it is necessary not to increase the speed and ensure that all the teeth running around the circumference are intact.

How to avoid dulling a tool?

The tool becomes dull because it overheats during use. To maintain sharpness, drilling should be done at low speed. There is no need to press the power button all the way down. When drilling thick workpieces, you need to use coolants or pastes.

If there is no cooling lubricant, machine oil can be used instead. Coolant keeps the tool from overheating and reduces friction.

How to drill metal correctly?

When you turn on the tool, the drill may slide to the side, which makes it difficult to make a hole in the selected location.
You can cope with this problem using a core. It is a metal cylinder with a sharp point at one end. It is necessary to attach the sharp end to the marking and hit the back side of the core with a hammer. There will be a notch on the metal through which a hole is drilled. DISASSEMBLY 3. Drilling metal

Drilling thick workpieces

Not many novice craftsmen know how to drill a hole in thick metal. Deep drilling is more difficult than usual. In production, it is carried out using lathes. In them, the workpiece is fixed in a movable spindle, which rotates it.

If it is not possible to use industrial equipment, you can drill a deep hole using a drill. To do this, you need to purchase special guides for power tools. Additionally, it is necessary to use machine oil for cooling. During operation, you need to stop periodically to clean out the chips and allow it to cool.

How to drill with a drill?

Drilling metal with a drill requires following some recommendations:

1. To make a hole you will need an electric drill, a core punch, a hammer, machine oil and safety glasses.
2. Initially make markings.
3. Wear safety glasses.
4. When the pressure on the drill is low, you need to select the low speed position and start working.
5. Don’t forget to water the area being treated with coolant.

If you follow the technology and use high-quality tools, you can make holes of different diameters and depths. To drill straight holes or accurately select the depth, you can use a device called a “depth stop.” It is attached to an electric drill and adjusted to the desired depth.

How to drill with a screwdriver?

You can drill metal workpieces not only using industrial equipment or an electric drill, but also using a cordless screwdriver. This power tool is low power. Because of this, it is suitable for drilling holes of small diameter and depth.

Drilling is performed using industrial equipment and power tools. It is important to choose the right equipment and take into account the depth and diameter of the hole. To ensure that your equipment lasts longer, you should use coolant. You need to drill perpendicularly to avoid damage to the workpiece or tool.

Source: https://metalloy.ru/obrabotka/sverlenie/otverstij-v-metalle

Punching holes in metal

Punching holes and perforating material in the form of sheets or pipes is a fairly popular operation. Today, there are several options for its implementation, which differ from each other in the equipment used, on which the quality and accuracy parameters depend.

Metal perforation Punching holes in metal

In the manufacture of a large number of products, including decorative metal parts. Quite often there is a need for such operations as obtaining many holes of the same type. Most often they are used to fasten structural elements, but in some cases they can be considered as decoration.

The technologist, when choosing a method for processing a part, is guided by the requirements of regulatory, technical and design documentation.

So, when processing a sheet of metal with a thickness of 0.5 to 4 mm, the best option would be to use punching on specialized equipment.

What's the difference between hole punching and perforation?

By the way, quite often, punching sheet metal is called perforation. In fact, this process (punching holes) is nothing more than a type of perforation, which includes many other methods.

For example, punching holes in profiled metal, such as a pipe, is done using drilling or milling. In addition, to solve this problem, a technical laser is used, which makes it possible to obtain holes in tenths of a millimeter.

The equipment that is used to make holes can be divided into “conditionally manual” ones, that is, those that require the constant presence of an operator - a machine operator, and automated ones, which work with minimal human intervention. As a tool for punching holes in metal, various types of punches, stamps and some others are used.

Manual pressCoordinate punching presses

The first group includes equipment operating from a mechanical, hydraulic or other type of drive. The second are fully automated machines operating under CNC control, for example, coordinate punching presses or a hole punching machine.

Manual process

Manual methods for making holes in metal include drilling and punching. Drills and related equipment - drilling machines or hand drills - are used as tools for punching holes in metal. For manual punching of the tool, a bit and a percussion tool (hammer, sledgehammer) are used. This punch can be installed on hand presses.

Manual punching process

Drilling of holes is carried out on drilling, milling or lathes. Drills are used as a working tool. For final shaping of the hole, countersinks, counterbores, and reamers are used. With their help, ovals are eliminated, chamfers are formed, and the hole accuracy and surface cleanliness are increased.

To punch holes in metal, different presses are used - pneumatic, hydraulic, etc. The forces developed for the effective operation of a stamp, consisting of two parts (a punch and a matrix), range from several kilograms to hundreds, or even thousands of tons.

Punching holes on combined press shears

Often in production, combined presses and shears are used to produce holes.

Punching holes on combined press shears

This device consists of several mechanisms that allow you to process a metal profile, for example, a corner, cut strips of metal, cut in the shape of straight or triangles and, of course, a tool for punching holes in the metal is installed on these scissors. As a rule, it consists of a punch and a matrix. The punch has the diameter of the hole to be punched. The matrix has a hole in its body corresponding to the size of the punch. Through it, cutting waste is removed.

It should be noted that the above methods for producing holes are not characterized by high productivity, especially in conditions of large-scale or mass production. The advent of automated equipment eliminates this problem.

Punching holes on presses

The use of equipment operating under the control of a CNC system has led to a reduction in the labor intensity of production processes, and accordingly this has a positive effect on the cost of the finished product.
The fact is that the control program, which is entered before starting work, contains precise data regarding the location of the holes on the sheet.

Punching holes on presses

For example, a revolving punching machine is equipped with a drum on which punches (tools for punching holes in metal) of different sizes and shapes are installed. When working, the program automatically selects the required tool. This engineering solution allows you to change the tool without stopping the operation of the machine, and increase the speed of obtaining the finished product. With this type of equipment it is possible to produce up to 1,500 holes per minute.

Obtaining a finished product consists of several operations. The first is to lay the sheet of metal on the workbench. To secure it to it, different types of clamps are used.

Once installed and secured, the operator launches the control program. After this, the movement of the workpiece begins. According to the coordinates specified in the program, at the required point, the clamping device is lowered, fixing the sheet in the right place.

After pressing, a blow is applied by a punch (punch).

A rotary tool can be installed on the tool drum, which significantly expands the capabilities of the machine and allows cutting contours of complex shapes.
A press for punching holes in metal allows you to perform, in addition to breakdown, the following operations:

• bullet - extrusion, obtaining edges of different directions;
• molding;
• incomplete punching.

Coordinate punching of metal

This method of obtaining holes implies that the holes will be obtained in a certain sequence. This operation can be used in the manufacture of both simple parts and rather complex metal structures. Such processing of sheet metal requires high precision from the equipment and control program, since errors in the settings and program code can lead to substandard products.

Coordinate punching of metal

Metal punching as a technological operation has existed for quite a long time, but in recent years, thanks to the advent of systems with numerical software, it has changed significantly. Thus, modern equipment makes it possible to perform operations on punching holes with an accuracy of their placement up to 0.05 mm.

Coordinate punching equipment allows processing steel of different grades with a thickness from 0.5 to 8 - 10 mm.
Coordinate punching of a metal sheet is used in the production of housing parts, fastening kits, etc. To obtain a set of holes, a series of punch blows is used on the sheet. The breakdown order is entered into the control computer program.

By the way, the use of computer programs and appropriate tools for punching holes in metal guarantees the quality of the finished products.

The use of coordinate punching presses for punching holes in metal provides a manifold increase in production speed and therefore it is used for large-scale and mass production of parts from sheet metal.

We must remember that the quality of the resulting product directly depends on several factors, including the quality of the tool, equipment settings, and the quality of the software used to create the control program.

Coordinate punching and its disadvantages

But it should be noted that, in principle, regardless of the method of obtaining a group of holes, the defects in manual and automated punching are the same.

Hole offset

Most often, when making a group of holes, you can encounter such a defect as displacement of the holes relative to each other or the sides of the sheet. This defect may occur due to errors in the program, incorrect machine settings, etc.

Burrs

This defect appears due to the fact that the dimensions of the punch and matrix are incorrectly selected. In addition, burrs appear as a result of poor-quality sharpening of the tool.

Punches and dies

Furrows

There are frequent cases of beards appearing on the surface of the hole along its axis. They are caused by the presence of defects on the punch surface.

Grooves when punching metal

Cracks

The formation of cracks at the edges of the punched holes is caused by the fact that their diameter is close in size to the thickness of the sheet.

Calculation of the required punching force

The metal cutting process is characterized by the fact that during this process a rather complex load pattern appears, which is concentrated in the area where the punch, the material being cut and the matrix interact.

The punch is made in such a way that it does not enter the material with its entire end, but only with the outer annular part. The response comes from the matrix. Moreover, the pressure arising in the interaction zone of these three components is distributed unevenly.

In other words, during the cutting process a pair of forces arises that form a circular bending moment. Under its influence, the sheet bends. As a result of this bending, pressure is generated, which affects the punch and the edge of the matrix. In addition, it is necessary to take into account the fact that tangential forces appear under the influence of friction forces.

As can be seen from the above, when punching, a non-uniform force field arises. Therefore, when carrying out calculations, a conventional value is used - shear resistance.

As a result of the research, the resistance depends not only on the properties of the metal, but also on the level of hardening, the thickness of the cutting, the gaps in the punch/die pair and the speed of the cutting process.

Source: https://stankiexpert.ru/spravochnik/obrabotka-davleniem/probivka-otverstijj-v-metalle.html

How to drill a hole in metal

Metal products, compared to parts made from other materials, have increased hardness and strength, so to successfully work with them requires adherence to the technological process and the use of high-quality cutting tools.

Tools for metal drilling:

• Electric or hand drill;
• Twist drill;
• Kerner;
• Hammer;
• Protective glasses.

Metal drills are selected based on the diameters of the holes and the properties of the material being processed. As a rule, they are made from high-speed steels, such as R6M5K5, R6M5, R4M2. Carbide drills are used to work with cast iron, carbon and alloy hardened steels, stainless steel, and other difficult-to-cut materials.

The power of the electric drill must be designed to drill a hole of the required diameter. Manufacturers of power tools indicate the corresponding technical specifications on the product. For example, for drills with a power of 500-700 W, the maximum drilling diameter for metal is 1013 mm.

There are blind, incomplete, and through holes. They can be used to connect parts together using bolts, studs, pins and rivets. If a hole is drilled for the purpose of cutting threads, you should pay special attention to the choice of drill diameter. Due to its beating, a hole in the chuck occurs, which must be taken into account. Approximate data are presented in the table.

Drill diameter Hole layout Result

5	10	15	20
0,08	0,12	0,20	0,28
5,08	10,12	15,20	20,28

To reduce the breakdown, drilling is performed in two stages: first with a smaller diameter drill, and then with the main one. The same method of sequential drilling is used when it is necessary to make a hole of large diameter.

How to drill metal correctly with a drill

The peculiarity of drilling metal with a drill is that it is necessary to manually hold the tool, give it the correct position, and also ensure the required cutting speed.

After marking the workpiece, you should mark the center of the future hole. This will prevent the drill from moving away from the specified point. For ease of work, the workpiece should be clamped in a bench vice or placed on a stand so that it takes a stable position. The drill is installed strictly perpendicular to the surface to be drilled. This is important to avoid it breaking.

When drilling metal, you do not need to apply much pressure to the drill. On the contrary, it should decrease as you progress. This will prevent the drill from breaking and will also reduce the formation of burrs on the exit edge of the through hole. Care must be taken to remove chips. If the cutting tool is jammed, it is released by returning it to reverse rotation.

Selecting cutting mode

When using a high-speed steel tool, you can focus on the rotation speed according to the data in the table. When working with carbide drills, the permissible values ​​are 1.52 times higher.

Drill diameter, mm Rotation speed, rpm

up to 5	610	1115	1620
13002000	7001300	400700	300400

Drilling of metal products must be carried out with cooling. If it is not used, there is a high probability that the tool will lose its cutting properties due to overheating. The cleanliness of the hole surface will be quite low. An emulsion is usually used as a coolant for hard steels. At home, machine oil is suitable. Cast iron and non-ferrous metals can be drilled without coolant.

Features of drilling deep holes

Holes are considered deep if their size is greater than five drill diameters. The peculiarity of the work here lies in the difficulties associated with cooling and chip removal. The length of the cutting part of the tool must be greater than the depth of the hole. Otherwise, the body of the part will block the screw grooves through which chips are removed and liquid for cooling and lubrication is supplied.

First, the hole is drilled with a rigid short drill to a shallow depth. This operation is necessary to set the direction and centering of the main tool. After this, a hole of the required length is made. As you progress, you need to remove metal shavings from time to time. For this purpose, use coolant, hooks, magnets, or turn the part over.

Source: https://tehnouzel.ru/tehnologii-remonta/kak-prosverlit-otverstie-v-metalle.html

How to make a tapered hole in metal

The working part of a step drill for metal (also called a cone drill) is formed by a spiral groove and a number of stepped annular transitions of different diameters. Thanks to this unique design, step drills allow you to determine at any time during processing what diameter the hole has been formed.

One step drill can replace a set for metal processing, including crowns

At first glance, it may seem that using such drills (which, by the way, are quite expensive) does not make much sense, because you can always select a tool of a certain diameter and use it to create the required hole. Meanwhile, conical tools for drilling holes have a number of unique advantages that make their use justified in many cases.

Scope and design features

Cone (or step) drills have a long working life, which is ensured by the high strength of their cutting edges. Unlike a conventional drill, a cone drill allows you to perform technological operations that in any other situation would require the use of several tools. It is this versatility that largely explains the high cost of drills in this category.

The conical drilling tool, due to its design features, allows processing at high speed, at which the quality of the edge of holes formed even in thin sheet material is not reduced.

Step drill device

Cone drills can make holes not only in metal, but also in drywall, wood, plastic, etc. They also successfully cope with dense metal, which cannot be said about any other type of drilling tool.

The sharp tip of the step drill not only eliminates the need for a centering tool, but also easily cuts into the structure of even the densest metal. The resulting hole does not require additional processing using a needle file and a grinder.

Most step drills are capable of drilling through metal up to 4mm thick

The progressive channels of the step drill, arranged in a spiral, are made in different sizes with a smooth transition. This design feature increases the efficiency of the cone drill when working with thin sheet metal by at least 50%. In addition, when drilling metal parts with a tool with such spiral translational grooves, its smoothness is ensured.

Cone-type drills can be used either in conjunction with a manual drilling device or when installed on special equipment.

An abrasive coating based on diamond or titanium chips can be applied to the working surface of step drills (this does not contradict the requirements of GOST).

This coating of the cutting surface significantly increases its strength, which makes it possible to minimize the frequency of sharpening.

Naturally, you can count on this advantage of using a sprayed cone drill if the rules for its operation are followed and the permissible load on it is not exceeded.

These drill bits are made from high quality high speed steel with titanium coating.

One of the tasks that can be solved with the help of a cone drill is the correction of defects in holes produced by a tool of another type. Such defects, in particular, include torn edges. Step-type drills are practically irreplaceable in cases where it is necessary to obtain high-quality holes in thin sheet metal, products made of fiberglass and other polymer materials.

Considering all of the above, we can conclude that cone drills are even more versatile than traditional twist-type tools. That is why they will not be superfluous at the production site and in the home workshop. How convenient and effective a cone tool is, the cost of which depends both on the diameter of the working part and on the type of spraying, can be judged by the video of processing with its use and by reviews from specialists.

What to look for when choosing a conical drill

You should make a choice of a tool such as a conical drill for metal only after you have become familiar with its characteristics. The color of a step drill can tell you a lot about it.

• The gray-steel color of the manufacturing material indicates that the drill has not been subjected to any heat treatment; therefore, you should not count on its high quality.
• The conical tool, the surface of which is black, has been treated with hot steam, which increases its strength.
• The golden color of the steel indicates that all internal stresses in the metal were previously eliminated, which improved its quality characteristics.
• If the surface of a step drill has a bright golden hue, it is highly wear-resistant. This is provided by the titanium nitride contained in the metal. The fairly high cost of such products is fully compensated by their long service life.

The marking of a step drill indicates its characteristics

For the production of cone drills, various types of steel are used, which are determined by marking. If the marking contains the abbreviation HSS, this means that with this product you can perform high-speed processing without worrying about it deforming or losing its strength characteristics under intense heating.

When choosing a step drill, pay attention to the main dimensions

When choosing cone drills, you must also consider the following parameters:

• diameter, which completely depends on the characteristics of the holes that need to be obtained;
• brand (this parameter largely determines not only the quality of the product, but also its cost);
• compliance of the purchased conical drill and the material from which it is made with all GOST requirements;
• possibility of multiple sharpening (here you should be guided only by your own preferences and experience in sharpening spiral and conical drills in accordance with GOST requirements).

Self-sharpening

Drills, which are called stepped or conical, allow you to create holes with a diameter of 4 to 32 mm and are available in two versions: with the ability to sharpen or with a design that does not involve this technological operation. The high cost of products belonging to the second type is justified by their durability.

Their cutting edge (subject to all operating rules) does not become dull for a long time. It should be borne in mind that sharpening them without the appropriate experience can only lead to the fact that they become unsuitable for further use.

Cone drills of a certain configuration can be sharpened with a triangular abrasive rod

In order to properly sharpen a step drill, just watch the training video and follow the recommendations of qualified specialists. To perform this procedure, you don’t even have to rely on the drawing, but simply restore the original geometric parameters of the product.

Also, in some cases, it is permissible to use for these purposes thin abrasive diamond bars intended for sharpening knives, scissors and other tools.

Such a tool, like spiral drills with a conical shank, can be sharpened using a special machine equipped with an abrasive wheel, the working surface of which can be covered with ordinary sandpaper.

The geometric parameters of step drills, the guide grooves of which have a rectilinear shape, can be restored manually, and products with spiral grooves are best processed using a sharpening machine. It should be borne in mind that it is easiest to restore the geometric parameters of high-quality step drills.

Cost of step drills and recommendations for their selection

If there are no problems with the purchase of conventional spiral drills, the landing part of which is made in the form of a Morse cone, then the choice of a stepped-type drilling tool has some features. Its cost is influenced by two main parameters: working diameter and material of manufacture.

A consumer who is planning to purchase a step drill may be misled by the serious price range. To bring some clarity to this issue, we can look at some price examples. Thus, products for forming holes with a diameter of 4–20 mm are distinguished by their relatively low cost (400–500 rubles). A step drill from domestic manufacturers, which allows making holes with a diameter of 4–30 mm, will cost the consumer almost twice as much (1,100 rubles).

Such a set of three Swiss-made Bosch drills costs 8–10 thousand rubles

Many organizations that sell step drills offer them at a fairly high price, without in any way confirming their quality characteristics.

When purchasing a tool from such organizations, as well as from places where it is sold at low prices, the consumer should be prepared for the fact that the quality of the drill will be in great doubt. That is why it is necessary to buy cone drills only from those companies that are ready to provide all the necessary certificates.

You should also pay attention to the markings of the drill, by which you can determine that this is a certified product with characteristics that meet the requirements of GOST.

Anyone who is planning to purchase a cone-type drill should keep in mind that its rather expensive cost is due to the fact that it is characterized by exceptionally high quality, versatility of use, reliability and durability.

Source: https://respect-kovka.com/kak-sdelat-konusnoe-otverstie-v-metalle/

How to make a tapered hole in metal - Metalist's Guide

Good day, dear readers of the site “Electrician in the House”. In this article, I would like to share with you one of the universal devices that facilitates the process of drilling holes of different diameters - a step drill for metal.

People often call this instrument “carrot” because of its similarity to this vegetable (perhaps there really is a similarity, they are very similar in shape).

What is the versatility of this drill? And its versatility lies in the fact that it is tapered and has sections marked along the length of the barrel.

Designed for drilling holes in plastic, wood, metal and other materials.

I’ll say right away that it won’t take thick materials, but thin materials up to 5 mm are just right. Very convenient when you need to drill several large diameter holes, for example 10 mm and 26 mm. This is done with one such cone-step drill without many additional drills and replacing them in the drill chuck.

Let's take a closer look at the design of step drills, their characteristics, and how they can be used.

Why do you need a step drill for metal?

Any craftsman must have such a tool as a drill, so that when performing this or that work he will be able to drill holes of the required size in certain materials - wood, concrete, brick, plastic, metal. Currently, the market offers specialized drills - designed for processing a specific material. Each of them has unique characteristics and features inherent only to it.

The characteristic of any drill is its diameter. It determines what size hole can be drilled in a certain material.

Today, dear friends, I want to present to your attention a universal drill that can successfully replace conventional drills.

Intended for metal processing, this drill has a non-standard shape. It also stands out in that it provides, without any additional devices, the ability to drill neat and precise holes on the surface of any material.

For many craftsmen, working with this drill will be new. They differ from others in the quality of drilling, even if the metal is very thin.

Those who have ever tried to drill a hole in metal up to 1 mm thick will understand me: firstly, the drill begins to walk along the surface, and secondly, it begins to bite the edge and the hole no longer turns out to be round, but triangular.

With their help you can drill holes in plastic, pipes, wood, and drywall. In this case, you will not need to use a centering device, which will significantly simplify the work.

This tool is often used to grind an already made hole. With its help, you can quickly remove chips that have formed along the edges, so there is no need for a needle file or sandpaper, which are used to process holes by hand.

The stepped drill has a special structure that looks like progressive channels. Each subsequent channel has a larger diameter than the previous one. In this case, the transition between them is made at an angle of 35-45 degrees. This feature provides a significant increase in the efficiency of processing thin metal (at the level of 50%).

I purchased this tool on the Aliexpress trading platform. The set included three drills with different numbers of steps and different diameters. The first drill has five stages from 4 to 12 mm. The second drill has nine steps from 4 to 20 mm. And the third (the largest) has 15 steps from 4 to 32 mm.

In each of them the step pitch is 2 mm. The step pitch is the diameter of the next largest section, that is, each subsequent step increases the diameter by 2 mm. For example, if in our example the drill is 4-32 mm with a step of 2 mm, then we get 15 steps: 4, 6, 8, 10, and so on up to 32 mm.

Design and characteristics of a cone-step drill

Let's look at the design of the drill itself. The sharp tip with which this product is equipped easily penetrates any metal, no matter what its density. At the same time, the absence of the need to use centering devices significantly simplifies the process of drilling holes.

Using a conventional twist drill with a diameter of 9 mm or more to process thin metal, you are guaranteed to encounter difficulties. The primary problem will be the impossibility of its precise centering. This is due to the fact that its tip is very large. But in order to achieve the goal using this tool, you will have to first drill a smaller hole, and then enlarge it to the required size using an existing conventional twist drill.

Additional convenience of using a step drill is provided by the diameters of its thickenings marked on the sections, so you will not need to use a caliper to determine them.

The non-standard structure of this tool makes it possible to drill round-shaped holes that have different diameters in products made of different metals - steel, including stainless steel, aluminum and others.

You need to know that a metal step drill is designed for drilling holes in thin sheet metal, the thickness of which does not exceed 4-5 mm. The special structure of the tool prevents the occurrence of burrs and provides the ability to grind a finished hole.

From the front, this tool looks like a cone with two cuts. They perform the function of cutting metal - drilling it. After moving to the next step, a chamfer is formed for the hole that was drilled by the previous step.

The tool has a hexagonal shank, which ensures better fastening in the chuck.

Please do not confuse the concepts of step drill and cone drill . They differ from each other in the design features of the working part. A cone drill has a head with a smooth surface, a step drill has a head with special marked steps that have cutting edges. Using a step drill, the diameter of the drilled hole can be selected based on the markings of the sections, and not relying on the “eye gauge”.

This provides increased convenience if you need to drill a hole of a certain diameter or match it to a cone. A step drill for metal has a number of advantages in comparison with other products with a similar function.

Advantages of step drill

Many craftsmen wonder: is it rational to buy such an expensive tool? After all, the selling price of this product can vary up to 2 thousand rubles, or even more. It is directly influenced by the material of manufacture, the level of strength, the type of coating applied to the working part and other characteristics that are a priority when choosing a drill.

In general, friends, you can write for a long time about how cool the drill is, the instructions even say that the coating is made of titanium nitride (which I doubt, of course, China after all), but for myself I emphasized the following REAL advantages:

1. 1) allow you to work with wood, metal, plastic and other materials. The diameter of the holes that can be drilled with them ranges from 4 to 32 mm (the step between them is 2 mm);
2. 2) the tool is truly universal, since the master does not need to purchase a set of single drills in order to drill holes with different diameters;
3. 3) marking of diameters on the body - convenient and practical, eliminating the need to use a caliper to measure them;
4. 4) the maximum thickness of material that this drill can work with is 5 mm. The edge simply won't allow it anymore. But if you need to make a through hole of the required diameter in metal up to 10 mm thick, then you can be smart and drill a hole on both sides;
5. 5) the tail has a hexagon shape, and this ensures better reliability of its fastening in the chuck of an electric drill or screwdriver.

Source: https://ssk2121.com/kak-sdelat-konusnoe-otverstie-v-metalle/

A tool for making holes in metal with your own hands - a profile cutter

Hi all! Today I will show you how to make a simple homemade project from a steel strip, a bearing and a hinge, with which you can make even holes in sheet metal without much effort.

To make the tool you will need:

• Steel strip
• Big bearing
• Loop to fit the inner diameter of the bearing

Tool making

First of all, you need to measure 40-50 cm of steel strip and divide it exactly in half, then clamp it in a vice and bend it, as in the photo below.

Now you need to take one part of the loop, which is without a guide, and cut it exactly in half.

It should fit tightly into the bearing.

Now we fix the two parts so that one part of the loop is flush with the surface of the bearing, and the other sticks out a little, and weld them to each other.

Then we move on to the next stage - we install the part on the edge of the bent metal strip, with the protruding side towards the surface and weld them together.

Now we take the second part of the loop and make markings as in the photo below. We need to cut off half of the thick part and the edge of the guide.

The thin edge needs to be sharpened with sandpaper and made something similar to a cone but with a blunt end.

We install this part on the second edge of the metal strip so that it fits exactly inside the bearing - on the opposite side. In this position, you need to weld the part into the surface of the strip.

Now our tool is ready, the result is something similar to a hole punch - although this is a hole punch only intended for metal. This is such a beauty we have!

This device works very simply - you need to place the sheet on the surface of the bearing and hit the second part of the tool hard with a hammer. The holes turn out smooth and neat, I think the tool turned out to be not at all useless, in my opinion, it will find its use in any workshop. Below you can see how it works:

That's all, thank you everyone for your attention.

Source: https://sdelaysamodelku.ru/instrument-dlya-prodelyvaniya-otverstij-v-metalle-svoimi-rukami-prosekatel-profilya/

How to widen a hole in metal

Drilling large holes is not a problem if you choose 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 getting a hole with a diameter of, for example, 15 mm requires a lot of effort.

To drill a large diameter hole in metal, special devices and core drilling technology are used.

How to burn a hole in metal yourself using electric welding?

Reading time: 4 minutes

When we need to make a hole (or, more correctly, a hole) in metal, we use a regular drill and metal drills. However, this method is not always convenient and simple if you need to make a hole of large diameter. In this case, a welding machine and an electrode will help. With its help you can burn a hole of any diameter, even in thick metal. In this article we will briefly explain how to cut metal using electric welding technology.

general information

Many home craftsmen are accustomed to thinking that welding should be used only when two metal workpieces need to be connected. However, having a welding inverter and electrodes in your hands, you can perform not only welding, but also metal cutting. This technology is useful if you need to make a hole in a workpiece.

You don't need to be a professional to make a hole in metal with an electrode. It is enough to know the operating principle of the inverter and be able to apply it in practice. The cutting process is simpler and faster than welding, since there are no such high requirements for the quality of the seam. With practice, you can achieve a fairly smooth cut with neat edges. Therefore, cutting is suitable even for those who have never used a welding inverter.

What should you have on hand?

To make a hole in metal, you must have an inverter, electrodes, as well as a hammer and a brush with metal bristles.

Inverters come in different types: cheap and expensive, professional and household, powerful and not very powerful. In essence, it does not matter which inverter you use for cutting. The main thing is that it is in good order.

As for electrodes, there is a wide choice. Previously, cutting was performed with the same electrodes as welding. But now there are many brands on sale that are designed specifically for cutting. They are all good in their own way. The most popular brand of cutting electrodes is OZR. They provide a more or less even cut and allow you to get the job done quite quickly.

If you decide to use conventional electrodes for welding, then be prepared that the cut will not be the most aesthetically pleasing, and the work itself will proceed more slowly, and the arc will burn unstably.

Source: https://svarkaed.ru/svarka/poleznaya-informatsiya/kak-samostoyatelno-prozhech-otverstie-v-metalle-elektrosvarkoj.html

Navy

Metalworking is performed with special cutting tools, using machines and mechanisms. Drilling holes in metal is not an easy task. This technological operation requires basic knowledge about the material, machines and cutting technology. Sometimes it is difficult to select a drill taking into account different degrees of metal hardness and select cutting modes.

Required Tools

Professional metal drills (for example, Bosch, Makita, Metabo or Hawera) are made exclusively from high-speed steel HSS. Some are coated with a protective layer, which increases their wear resistance when drilling.

Hand tools - drills and drill bits should be selected carefully. If you have no experience in this area, you should seek advice from a store employee. Purchasing an expensive, high-end drill does not always guarantee its long service life.

Compliance with the technology for making holes in metal and a correctly selected drill significantly increases its service life and protects against premature wear. Basic rules for operating cutting tools:

• Selecting the appropriate type of gimlet for drilling metal of a certain hardness. Many manufacturers have developed entire programs using which you can select the appropriate tool.
• Selecting cutting modes, setting the correct rotation speed.
• Correctly selected feed, application of appropriate pressure on the cutting tool.
• Application of cooling. An oil-based emulsion is recommended.
• Proper fastening of the material (for example, in a vice).
• Attaching the drill to the stand is precise and perpendicular.
• Use of an expanded set of gaskets when drilling through holes.

Technological process

Drilling is the process of removing small parts of the material being processed, chips, using a drill. During drilling, the temperature of the workpiece increases. The cutting force leads to damage, the friction force causes a change in the geometry of the cutting edge, plus high temperature, as a result the tool gradually becomes dull.

Most drills are made from high-speed steel with varying cobalt content. It is very important that it is sharpened correctly: the cutting edges are of equal length, the jumper between them is located along the axis of the cutting tool.

This ensures that both edges will perform identical work during the drilling process. The drill will not have runout, the hole diameter will correspond to the size, and heating of the part and the tool will be minimized.

A drill-drill with chamfer correction has a smaller jumper, due to this the cutting edges are lengthened. With such drills you can drill a hole without preliminary marking with a core.

The choice of drills depends on the type of work being performed . NWKa HSS Baildon drills are optimal for drilling:

• structural steel;
• cast iron;
• brass;
• bronze;
• aluminum;
• plastics;
• tree.

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Drilling metal

A special feature of the drills is the presence of a sharp edge, which allows for mechanical processing of the material. They have an equal diameter along the entire length, and the blade is sharpened at an angle of 118°. The sharpening angle varies depending on the hardness of the material, for example, for alloy steel, it is 135°. This type of drill is made of HSS steel with 5% cobalt. During operation, they require cooling with special drilling oil .

In order to drill a nozzle in metal evenly and accurately, it is necessary to use a guide device - a jig.

When drilling, it is best to use as little force as possible. When drilling a through hole, when the moment of exit of the cutting tool approaches, it is necessary to reduce the feed so that the part does not tear out, the drill does not break, or burrs do not form.

A conical drill is used to produce a conical hole in metal. It is used as an independent tool. They can drill a cylindrical hole, turning it into a conical one. A conical hole in the metal is made on a lathe in order to drill and bore the resulting nozzle with a cutter.

Cutting modes

The most common mistake is using too high a drilling speed . The more difficult the material to process, the lower the drilling speed should be used. For example, in the case of drilling an 8 mm hole in brass, the drilling speed should be 2500 rpm, for harder alloy steel - 800 rpm. The best sign that the drilling speed is correct is nice, long chips.

Depending on which tool to choose, cutting parameters are important. It is necessary to select the correct rotation speed and feed. Bench-top drilling machines provide the best parameters, but they cannot be used everywhere. It is necessary to follow the principle: the lower the speed and the lower the feed, the longer the tool will last.

For example, take stainless steel, 8mm hole, 4mm thickness, cooling lotion or oil, HSS drill bit, drill or drilling machine: The revolutions should not exceed 400 rpm, and the feed should not be more than 0.10 mm/ turnover In other words, you can drill at a speed no higher than 400 rpm. But this speed is not optimal. Therefore, it would be optimal, for example: 170 rpm, and the feed for every 30 revolutions is 1 mm (three times less than recommended).

Cooling the drill during the drilling process is very important. Use emulsions, oils, drilling sprays. Water should be avoided, as it does not have the properties of lubricating fluids, but only cools.

Large diameter holes

To the question of how to drill a large diameter hole in metal, there is only one answer: in the technological process of drilling necks . For example, you need to increase the neck and get a size of thirty millimeters in diameter. First, it is drilled with a tool of a smaller diameter, for example, four millimeters, then to a size of 8 millimeters, then 12 millimeters, and so each size is expanded to the result.

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A large diameter neck in a product can be made on a lathe. The operation is as follows: drilling a hole, boring the neck of the desired size. As pre-drilling is required, the process can be divided into stages: small-diameter drilling, reaming with a gradual increase in drill diameter.

Drilling thin sheet metal

The peculiarity of obtaining an armhole in a thin sheet of metal is its reliable fastening . After the drill comes out to the other side, there is a danger that the sheet may suddenly jam and tear out if it was held in your hands. The best way to securely fasten a sheet is a clamp. In this case, the risk that the tin will be torn out is much less. The number of burrs formed is reduced, which will greatly facilitate the finishing of the element.

If the metal is 0.1 millimeter thick, you can make a hole without a drill by using a metal punching tool. Its design is very simple, like pliers. A punch is attached to one lever, and a matrix to the other. The principle is the same as cold stitching using a stamp.

To cut a through groove in sheet steel, you need to drill a successive row of holes according to size, connecting them into a single slot using a chisel and hammer. To do this, it is necessary to cut off the bridges between the holes and smooth out the unevenness with a file.

Metal pipes

When drilling a metal pipe, make sure that the workpiece is securely secured in the vise. It is advisable to mount the drill on a vertical stand. Insert a piece of wood of the same shape and size inside the pipe, which will protect the pipe from deformation. In this case, use low feed.

Getting narrow nozzles

Drilling deep holes of small diameter can only be done on a special machine or lathe using a device. The part is clamped into a 3-jaw chuck and checked for runout with an indicator.

The device is mounted on a tool holder. A drill chuck with a drill is installed in the fixture. First, the hole is centered, then the nozzle is drilled to a given depth.

Using a tailstock is problematic, since the overthrust must be constantly removed to remove chips and lubricant.

To obtain vertical holes, a right angle drilling device is used. For an electric drill, this is a vertical stand at an angle of 90 degrees to the base. The easiest way is to use a vertical drilling machine.

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Read also: Stand for drill kwb reviews

Today, every home craftsman has the necessary tools for cutting metal, drilling, and stripping. But what if you need to drill a large diameter hole? After all, the maximum cross-section of a conventional drill for a hand-held electric drill is only 20 mm.

Tools for drilling large holes

There are several ways to drill a hole with a diameter greater than 20 mm. For this, special devices are used:

• Cone drill. It will not be possible to drill a large number of openings of the same size. But for home use it is quite acceptable. The maximum cross-section is up to 40 mm. The thickness of the processed metal is 5-6 mm.
• Tapered step drill. It is more convenient to use, since each step is formed through a smooth spiral transition. When drilling, this makes it easy to track the actual diameter of the hole. With its help you can drill a circle up to 40 mm in diameter on metal up to 6 mm thick.
• Bimetallic crowns - suitable for preparing holes up to 109 mm in steel products up to 5 mm thick. When working, it is strongly recommended to use specialized lubricating and cooling compounds, which will ensure maximum service life of the cutting tool. An adapter is also required to install the device on an electric drill. On average, using a bimetallic crown, you can drill 5-20 openings, depending on its quality, which, accordingly, is reflected in the cost.

How can you drill a large hole without extra costs?

For this method, you will need a small cross-section drill (5-6 mm is enough), as well as a milling cutter or a used grinding wheel (corresponding to or slightly smaller than the diameter of the hole) for an angle grinder. The option is more labor-intensive, so it takes much more time.

On a metal blank, 2 circles are drawn with a pencil:

• 1 – for the future hole.
• 2 – depends on the cross-section of the drill, that is, when using a 6 mm tool, the diameter of the intended circle will be 6 mm smaller than the previous one.

Along the 2nd circle it is necessary to mark 2 places in opposite places and drill holes with a 6 mm drill. From the resulting openings along the intended line you need to retreat approximately 3 mm and again mark the places for drilling. Holes are drilled along the entire circumference. If necessary, the remaining sections can be cut with a chisel.

The hole will be jagged, so it needs to be bored out. This can be done with an electric drill with a cutter, but it is much more convenient with a grinder using grinding abrasive wheels of a suitable diameter. Using a grinder, you can quickly and evenly bore a hole to the required diameter.

Therefore, you should not throw away used abrasive wheels for grinders with a diameter of even less than 45 mm - they can always be useful in the household.

Source: https://morflot.su/kak-sdelat-bolshoe-otverstie-v-metalle/amp/