How to cut a circle in metal with a grinder. How to Cut a Circle in Metal: Best Techniques and Valuable Tips

Any design, whether in your home or in production, involves working with metal.

Often, during the operation of this material, the question may arise: how to cut a circle in?

It deserves attention, because from the choice the right tool and technology directly depends on the complexity of the process of performing work and the quality of its result.

Metal can be thin or thick and strong, so a variety of tools are used to cut it.

The choice of materials and cutting technology also depends on what diameter the circle is needed and how even it should be.

Jigsaw application

If there is a need for a perfectly even circle, you can use an electric one to cut it.

The work is carried out in several stages:

First, the thickness of the metal is determined and the appropriate saw blade for the electric jigsaw is selected.
Before cutting a circle in metal with a jigsaw, the outline of the circle to be cut is outlined on the working plane.
With the help of a drill and a drill (with a diameter of eight to ten millimeters), a hole is cut out from which work will begin.
A jigsaw saw blade is placed in the resulting slot and cutting continues as planned.

Cutting with this tool does not take much time and effort. Moreover, using a jigsaw, you can get a circle with perfect edges. But this tool is used only for working with metal of minimum or medium thickness (for example, 2 - 3 mm).

The use of grinders

The grinder is used in working with metal of small thickness. Form with this tool round hole You can follow these step by step instructions:

Before cutting a circle in metal with a grinder, marking is carried out so that its contours are clearly visible.
Along the entire length of the intended drawing, short segments are cut through the angle grinder disk, which will eventually connect.
The figure will look more like a polyhedron than a circle. Therefore, after cutting is completed, the product is processed and cleaned until the edges are sufficiently even and smooth. For processing, you can also use the grinder. If the circle is wide, you can grind the contours with a large disk.

When processing a cut circle with a grinder, you should be careful that the disk is inside the hole and, at the same time, is located in the same plane with the work sheet.

Cutting a circle in thick metal

In order to outline the exact contours of the figure that will be cut out of metal, you should use a ruler, a marking compass and a marker.

First, with the help, the required width of the compass slot is set so that it corresponds to the required diameter of the circle.

Then the center point of the circle is determined on the metal plane.

Contours are drawn from it with the help of a compass.

So that during the robots they are clearly visible, they should be drawn with a marker.

Cutting torch application

A circle in metal of medium thickness can be cut with a gas cutter. The work takes place in several stages:

The contour of the circle is outlined.
The tool burner ignites.
Burning flame is adjustable.
Gently and slowly, the torch is carried out according to the drawn drawing.

With this method, you can cut a hole in the metal, which has about four or five millimeters.

Welding Machine Application

If there is no gas cutter in your home arsenal, you can use a welding machine.

It needs to be adjusted to high level current.

Then a burning arc is substituted for the contour and held on it until a hole is formed.

Then you just need to slowly lead it along the drawing until you succeed even circle.

But the most important thing is to correctly adjust the power of the tool.

For example, if metal is used with a thickness of about four millimeters, a device operating at a power of about 150 amperes is needed. If the metal is thicker, the power of the tool will be greater.

To speed up the process, it is better to use thin electrodes. However, they burn out quickly and need to be replaced. Because of this, there will be a need for frequent heating of the metal, since it will have time to cool down during the replacement of the electrode.

How to cut an even circle from metal with a cutter is shown in the video:

People working with metal quite often have to deal with the need to cut a round blank from a metal sheet. In production, this problem is solved simply - with the help of oxygen-gas, plasma or laser cutting. For each type of these operations, specialized equipment is required, which there is no reason to have in private use. Therefore, in the conditions of private workshops, a circle of metal is cut out different ways- taking into account the available equipment.

Ways to cut a circle out of metal

In order to cut a circle out of metal, you will need:

gas cutting equipment;
welding machine;
angle grinder;
electric drill with a set of drills;
grinder;
manual lever scissors;
core;
marking circle.

Mark the center of the circle on the steel sheet in such a way that it is spaced from the edges of the sheet at a distance slightly greater than the radius of the circle. Place the leg of the marking compass in the trace of the core and draw a circle of the required diameter on the metal.

The most common and technologically advanced method is cutting metal using a gas cutter. To make the circle clearly visible, circle the outline drawn with a compass with a marker or chalk. Light the torch, adjust the flame and cut the metal in the marked circle. Theoretically, the thickness of the metal that can be cut with a flame cutter is 250-300 mm. In practice, such thicknesses are extremely rare.

You can cut a circle steel sheet using electric welding. Strike the welding arc at any point on the marked circle and hold the electrode in place until a hole is burned through the plate. After that, start melting the edge of the hole by passing the electrode along the drawn circle. Low-power welding machines operated by private owners can cut metal of relatively small thickness - a maximum of 4-5 mm. The cutting edges are uneven and melted, and the cut workpiece has irregular shape, which must be brought to round processing on lathe or by hand - on a grinding wheel.

A simple, but rather time-consuming operation is cutting a circle with a grinder. Cut in the sheet on all sides of the drawn circle lines that are tangential to it. How more quantity cut lines, the closer the shape of the cut figure approaches the circle. But in any case, it will not be a circle, but a polygon, which is to be brought to a circle by grinder.

A circle from a sheet of metal up to 3-4 mm thick can be cut using manual lever scissors. First, cut out a square with a circle inscribed in it, then cut the workpiece from all sides, running the scissor blades along the lines tangent to the circle. The shorter the length of the tangents and the greater their number, the less work will be required when turning the workpiece on a grinding machine.

The most time-consuming way to cut a circle is to drill holes around its perimeter. But sometimes, in the absence of other options, you have to resort to this method. From the same center from which the original circle was drawn, draw another one with a diameter greater than the diameter available by the diameter of the drill that will be used for drilling (usually 4-5 mm). Perform punching along this circle in such a way that the recesses from the core are separated from each other by a distance of the diameter of the drill. Drill holes in the punched places around the entire perimeter of the circle. Knock out a circle from the sheet with a hammer or sledgehammer, process it along the outer diameter on a grinding machine.

You will need

- gas cutting equipment;
- welding machine;
- angle grinder;
- electric drill with a set of drills;
- grinder;
- manual lever scissors;
- core;
- marking circle.

Instruction

Mark the center of the circle on the steel sheet so that it is spaced from the edges of the sheet at a distance slightly greater than the radius of the circle. Place the leg of the marking compass in the trace of the core and draw on a circle of the required diameter.

The most common and technologically advanced method is cutting metal using a gas cutter. To make the circle clearly visible, circle the outline drawn with a compass with a marker or chalk. Light the torch, adjust the flame and cut metal around the designated circle. Theoretically, the thickness metal, which can be cut with a gas cutter, is 250–300 mm. In practice, such thicknesses are extremely rare.

You can cut a circle from a steel sheet with . Strike the welding arc at any point on the marked circle and hold the electrode in place until a hole is burned through the plate. After that, start melting the edge of the hole by passing the electrode along the drawn circle. Low-power welding machines operated by private owners can have a relatively small thickness - a maximum of 4-5 mm. The edges from cutting are uneven and melted, and the cut blank has an irregular shape, which must be brought to the point of processing on a lathe or manually on a grinding wheel.

A simple, but rather time-consuming operation is cutting a circle with a grinder. Cut in the sheet on all sides of the drawn circle lines that are tangential to it. The greater the number of cut lines, the closer the shape of the cut figure approaches a circle. But in any case, it will not be a circle, but a polygon, which will have to be brought to a circle on a grinding machine.

A circle metal thicknesses up to 3-4 mm can be cut with manual lever scissors. First, cut out a square with a circle inscribed in it, then cut the workpiece from all sides, running the scissor blades along the lines tangent to the circle. The shorter the length of the tangents and the greater their number, the less work will be required when turning the workpiece on a grinding machine.

Metal is the material that the angle grinder (angle grinder) was originally designed to work with. Now with its help they cut reinforcing bars, various metal sheets, pipes different diameter, brick, concrete, stone, tile and other building materials. Due to the presence of a variety of nozzles, the grinder also allows you to polish and grind the surfaces of products. Cutting metal with a grinder is one of the main, most frequent works. To reduce the likelihood of injury, it must be performed correctly, with strict observance of the requirements of general and personal safety.

Bulgarian belongs to the category relatively hazardous power tools. You can get injured from a scattered disc or a tool that has fallen out of your hands. In both cases, the danger is associated with high speed rotation of the electric motor of the device.

To improve the efficiency of the grinder, expand its functionality, in practice, such accessories:

tripods;
clamps.

Their use improves the quality of sawing metal blanks, improve process accuracy. Also, working conditions are improving from a safety standpoint, and its productivity is increasing.

The use of additional devices allows you to use the tool as a machine tool designed to perform different types works.

In order to secure the cutting process as much as possible, you should work on metal with an angle grinder in compliance with a number of rules. They are conditionally divided into preparatory and main (working) activities.

Before starting cutting, it is necessary to carry out a number of manipulations.

If possible, the sawn material should be securely fixed in advance, for example, in a vice, in order to remove possible accidental movements. Do not hold workpieces in your hands or between your knees.

Proper tool operation

When you start sawing any part with an angle grinder, you should follow these rules.

When cutting metal, hold the grinder firmly with both hands.
Wheels can only be changed after they have completely stopped rotating and cooled down to an acceptable temperature by disconnecting the power tool from the mains.
Do not put a working tool on the ground or a table (do not let go of it).
Required intermittently for about 5 minutes stop for rest and keep the disk cool.
It is necessary to constantly monitor the condition of the cutting wheel, preventing it from being pinched by the edges of the workpiece being cut.
Do not leave a plugged-in tool unattended.
Use discs only right size specified in the operating instructions for the device you are using.
Better work done on the flat surface to keep the body in a stable position.
Make sure that the power cord is away from a rotating circle, sharp edges, objects heated to more than 100 degrees.
Movements not directly related to cutting should only be carried out with the power tool turned off.
It is necessary to be located on the side or behind the tool, doing the work with your own hands so that the parts of the body are not in the plane of the cut.

When the cutting of the metal with the grinder is completed, you should wait until the disc stops completely, disconnect the power cord of the tool from the mains. After that, it is recommended to make sure that there are no signs of fire. When cutting materials, right-handedly hold the handle of the device in the area of the on / off button right hand. Left hand at the same time, it is located on a handle screwed into the body of the power tool from above.

It is unacceptable to perform work using a grinder in a very tired state, or while under the influence of alcohol, psychotropic or narcotic drugs.

As for the question of which direction - towards itself or away from itself - the disk of the included angle grinder should rotate, there is no unequivocal answer here. The operating instructions indicate that the first option is correct. This is due to the fact that the resulting sparks fly off in the opposite direction from the operator, without causing harm. Also, fragments of the circle will fly in that direction if it shatters into pieces.

But in the case when a jamming of the disk rotating “on itself” occurs, the tool will fly off into the working one. For this reason, many experts prefer to cut metal so that the circle rotates “away from itself”. The power tool torn from the hands will fly in the opposite direction. This reduces the likelihood of injury, and clothing, shoes and gloves will protect the user from flying sparks.

Cutting sheet metal grinder

To cut metal of different types and thicknesses, use the appropriate cut-off wheels different thickness and diameters. The algorithm for cutting sheets is as follows.

For cutting with a grinder, sheet metal is pre-laid on a flat surface.
Mark with chalk (marker) the exact dimensions of the cut fragments on the surface of the sheet.
Sawing is carried out along the marked lines, without changing the angle of the initial inclination of the disk to the working surface, so that it does not jam and break the power tool.

If there are no skills in sawing sheet metal with a grinder, it is recommended that you first practice on soft material This will give you a feel for how the instrument works.

It must be taken into account that the lower near segment of the disk cuts the metal more efficiently.

When cutting a sheet of metal, to obtain a quality result, you should take into account such recommendations.

Cutting space required for better cooling pour water, which will also increase the life of the circle.
It is worth starting cutting metal only when the disk is rotating: you cannot turn on the tool if the stationary circle is in contact with the surface of the workpiece.
To cut sheet metal (thin sheet metal) or cut various geometric figures, it is more convenient to use small, worked out circles("stubs").
You should not press the grinder with significant effort: cutting should occur almost exclusively under the own weight of the angle grinder.
If the cutting wheel stops in the slot (when the power tool is turned off), then work can only be resumed after it has been removed.

If sawing the sheet is slow, you should change the working head. Excessive load on the angle grinder when cutting metal will lead to its overheating or jamming of the rotating circle.

Cutting a round hole in metal with an angle grinder

In practice, it is often necessary to cut a circle in metal, and only an angle grinder is available from the tools. But it is quite enough for this purpose. The algorithm of actions is the following.

A circle is drawn with a compass on the metal surface or according to a pre-made paper (cardboard) template with chalk or a marker.
Holding the grinder at an angle to the surface of the sheet, a preliminary marking cut of the metal is performed along the marked contour, making short movements with the disk (sawed in small segments).
Then, moving the nozzle in the same way, deepen the slot until it is completely cut out.

Need to cut along the outer contour of the circle so as not to reduce the size of the circle. If its diameter is small, then they cut, touching the metal with a disk point by point (without longitudinal movement of the nozzle). A round hole will turn out with an oblique cut, as well as with some minor flaws (they depend on the skill of the worker). After it, if necessary, processed.

The whole process of cutting a round hole in sheet metal via special device shown in video:

Features of working with thick metal, copper, cast iron, aluminum

When it is required to cut thick metal into separate fragments, it is recommended to additionally perform the following steps:

constantly cool the area of contact of the metal with the disk using cold water due to strong heating of the slot;

make all cuts only in a straight line;
different curvilinear contours should be cut in separate straight segments of small length, while removing unnecessary parts;
it is necessary to completely cut the workpiece in several approaches, with each subsequent deepening of the slot;
if it is required to cut corners, I-beams, channel bars, rails, then each of their structural parts is sawn separately.

Cutting cast iron, stainless steel, as well as non-ferrous metals such as aluminum and copper, is carried out using special circles designed to work with these materials. All the necessary information information about discs is contained in the labeling of these products, applied on their side. At the same time, the circles differ in the composition of the fillers:

in some, the additive is a heavy-duty material that can cut alloy steel;
others use soft binders.

Cutting stainless steel with conventional metal discs is prohibited, because they contain substances that lead to accelerated corrosion of the cut point. Aluminum and copper are very tough non-ferrous metals. They are cut with a grinder, pouring kerosene slot formed by the disk. In this case, fire safety rules must be observed.

Cutting pipes from different metals- This is a demanded operation during repair and construction work. It is necessary to cut off the products during the installation of sewer and heating systems, water lines. In this direction, the grinder copes well with various tasks. Disks for work are selected according to the material from which the pipe is made.

Application of angular grinder give a chance:

cut pipes at different angles, for example 45 and 90 degrees;
cut products large diameter;
evenly cut profile (rectangular or square section) pipes;
to make longitudinal cutting of tubular blanks;
sawing cast iron pipes;
cut thin-walled tubes.

If you need to cut a large diameter pipe, then using a grinder allows you to do this work without significant cash costs. But at the same time, labor productivity is small, and the risks are considerable. When long pipes lie on supports, they only saw off hanging parts. If you cut in the center, the cutting edges will pinch the cutting wheel, which will lead to jamming of the tool and possible injury.

Specialists not only cut pipes from different materials at the right angles, but also cut out holes of the required shapes in them. Work with profile and round blanks is carried out in a similar way, with the obligatory observance of safety regulations.

Cutting pipes at different angles

It is necessary to cut round and shaped pipes at an angle of 45 and 90 degrees when laying various communications. In any case, it is necessary to saw off the pipe evenly so that the elements that need to be connected are connected to each other as tightly as possible.

Rez at an angle of 45 degrees cylindrical pipes are carried out as follows:

take a regular square paper sheet;
fold it exactly diagonally;
wrap the pipe with this pattern;
a future cut line is applied with chalk or other marking device;
remove the template;
clamp the workpiece in a vise;
cut off the marked pipe fragment.

When applying the template, either of the two short sides of this triangle must be parallel to the central axis of the pipe.

When to cut at an angle of 90 degrees, pipes are simply wrapped in a circle (cylindrical) or around the perimeter (profile) with a sheet of paper. After that, mark the cut line. You can also mark the profile pipe very simply using a regular square.

When it is necessary to cut at an angle of 45 and 90 degrees a significant amount profile pipes make appropriate templates from this material, only larger. This allows you to perform the required measurements only once. At the same time, a construction square or a protractor is used for the initial marking. When the template is made, cut blanks are inserted inside it, marking the cut lines. Then sawing is done.

Templates are also made for other angles. This method improves labor efficiency.

Features of cutting cast iron and thin-walled pipes

Cast iron is brittle material. To saw through cast iron pipe grinder, act in the following sequence:

mark the cut line;
put under the pipe wooden block who will serve as her support;
make a cut along the contour with a depth of several millimeters;
insert a chisel into the recess made;
according to the instructions, they hit hard and sharply with a hammer.

After the impact, the pipe will split along the cut line. Its edges will be fairly even. If necessary, they are further processed.

To perform longitudinal sawing of the pipe, it is also important precise marking. For its application, various devices are used, for example, a construction thread (“beat”). The entire sawing process should be done carefully, slowly, so as not to stray from the marked line.

Thin-walled pipes are one of the varieties of this kind of products. They are often made of non-ferrous metals: copper or aluminum. Cutting them is difficult. In this case, circles for the grinder should be used corresponding to the material of the workpiece.

Sawing thin-walled tubes must be done very carefully, because they can easily be deformed even by applying a slight load.

To reduce the likelihood of bending the part being cut, various loose fillers are poured inside it, for example, ordinary cleaned sand.

Cutting profiled sheets and metal tiles

Quite often, in practice, one has to face the need to cut a profile sheet or metal tile. These materials are made of steel, which is coated with zinc and polymer protective layers, painted.

There are different opinions about the possibility of using a grinder for cutting them. The installation instructions say that the profiled sheet cannot be sawn with an angle grinder. To do this, you need to use other tools. But they need to be purchased, which is not always justified by the amount of work to be done, and also requires additional financial investments. When there is no tool other than an angle grinder, before sawing with a grinder, you should know the possible Negative consequences.

If you cut a metal tile or a corrugated board grinder, then protective covering in the saw cut area and a little near it will be destroyed, and the cut edge will begin to rust.
The material is out of warranty.
Flying sparks can ruin not only appearance the rest of the sheet (burn through the paint), but also damage the polymer coating.
The cut edge may be torn.

All the considered negative consequences can be minimized if you cut the corrugated board or metal tile with a grinder, observing the following recommendations:

perform all work immediately before installation;
treat sections with anti-corrosion compounds;
cover the cut edges with a primer and paint;
use discs for metal of minimum thickness (up to 1 mm);
to keep the edges neat, you need to cut pretty quickly;
carefully sand the torn edges.

Before sawing, as usual, carry out sheet layout.

If you need to cut a square, then do this:

draw it on the surface of the sheet;
cut the material along the marked contour with a grinder;
at the end, carefully cut out each corner.

Circles or other shapes are cut out, working in the same way.

The use of a grinder for cutting metal tiles and profiled sheets facilitates the work. It becomes more convenient to perform it, because you can adjust the sheets to size directly on the roof.

In order for the metal tile or profiled sheet to remain under warranty, you should measure the object and order the factory cutting of the sheets. You can also try to choose a material with such dimensions that cutting is not required.

Cutting metal with a grinder is cheap, practically affordable and quite effective method sawing it. In this case, appropriate discs without defects should be used for each material. Not only the quality of the result will depend on this, but also own health. Be sure, when sawing metal, it is required to follow safety rules and use tools personal protection. It should always be remembered that when working with an angle grinder, any shortcomings and inattention can result in injury. Therefore, you need to work carefully and carefully.

A hole in the metal will need the presence of at least one of the indicated devices: a grinder, a drill, an electric welding machine or a gas cutter. Each of these tools has its own advantages and is used depending on the size of the hole and the thickness of the metal. If the question is how to cut a large diameter round hole, then a gas cutter is best suited for this. But first you need to mark the hole with a compass. The contour should be made very clear so that it can be clearly seen even under the sparks of a grinder or welding machine.

After the hole is marked, the torch of the gas cutter should be lit. Next, you need to properly adjust its torch and make the cut itself. Move the cutter smoothly and at the same pace as the metal is cut. It's certainly not as difficult as drilling a hole in glass, but you still have to be careful. And if there is no gas cutter, then you can use an electric welding machine. True, this method is limited by the power of the apparatus and the thickness of the metal. The power of most of them is enough for 3-4 mm metal. Well, the cutting process itself boils down to the fact that you first need to install a welding dock, then light an arc and then burn through the metal according to the markup.

But how to drill a hole in metal, if not, neither gas burner, no welding machine? In this case, a grinder (angle grinder) can come to the rescue. However, it should be noted that it can only be used when the hole is not less than the cutting circle of the grinder, and the thickness of the metal does not exceed 3 millimeters. In addition, making a round hole at once will not work, because you have to make many short cuts along the contour of the circle. Even with their minimum length, it will still form not a circle, but a polygon. Therefore, after the operation is completed, you will have to trim the shape of the circle with a file.

Another way to drill a large hole is to use a drill. The advantage of this method is that the drill is a very common tool and it will not be difficult to get one. The disadvantage is that this method is the most laborious. Its essence lies in the fact that along the entire line of the contour, the metal is drilled through with many holes. It should not be forgotten that since the drill has a certain thickness, you need to mark another hole, the diameter of which should be reduced by the diameter of the drill. And then drill along a smaller contour. The same method can be used if you need to solve the problem of how to drill a hole in the wall.

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