When installing, repairing and replacing pipes in household devices, sewerage and water supply systems need to know how to measure the diameter of the pipe.

If accurate measurements are required, a vernier caliper or micrometer will be needed. With small errors, the diameter of the pipes is determined with a measuring tape, tape measure or other simple devices at hand.

If the area to be measured is in an easily accessible place, measurements are taken with a caliper or micrometer. Their dimensions should be such that the maximum distance between the heels of the micrometer or the jaws of the caliper exceeds the section of the pipe.

Depending on the accuracy of the device, the measurement range is from 0.1 to 0.001 mm. For measuring with a micrometer, its maximum value is 50 mm, for a vernier caliper - 150 mm. Readings on a caliper are read from the main and additional scales, on a micrometer - from the stem and from the scale on the beveled edge of the drum.

Determination of the pipe diameter

If it is not possible to find out the diameter of the pipe with the end measurement, for example, if it is in the groove, when measuring, the vernier caliper is applied to the lateral surface in its widest part.

If precision instruments no, it can be roughly determined using a right-angled triangle by putting it on flat surface... If the system is already mounted, a flat board is applied to the site, a triangle is applied to it.

If the exact measuring instruments no or the dimensions are large for these devices, the circumference Lt is measured. This is done with a measuring tape, tape measure, soft wire. To get its value, the resulting length is divided by 3.14:

If it is impossible to approach with measuring devices, the copying method is used. An object with known linear dimensions is applied to it - Matchbox, coin. This is not a measurement, but only an estimate. The method is good if the part is standard.

Often you need to know not the external, but inner size... Their throughput is determined by this parameter. It is of decisive importance for the installation of metal-plastic and polypropylene squeegees; fittings and other plumbing fixtures are made for it. First, the outer Dн is measured, the double wall thickness h is subtracted from it.

This method, how to find out the diameter, is called "cross-section measurement".

This method also allows you to determine the dimensions by taking an impression of the section on graph paper.

For internal measurements, there is a special device - an internal gauge.

Metric and Inch Units

There are two main types of sizes: metric and inch. In imported products, they are usually given in inches.

To convert values ​​from centimeters to inches, you need to multiply their value by 0.398.

Inch = Centimeter * 0.398.

To convert from inches to centimeters, you need to multiply their value by 2.54.

Centimeter = Inch * 2.54.

In most cases, external parameters are indicated in the metric system, internal ones - in inches.

Example. Inside dimension 0.5 inches. 0.5 * 2.54 = 1.27 cm = 12.7 mm.

You will need tools

• calipers;
• micrometer;
• internal gauge;
• tape measure, ruler, graph paper, measuring tape, right triangle;
• calculator.

Sizing does not require professional skills. But universal ways how pipe diameters are measured, no. Therefore, in each case, you need to look for a solution yourself.

One of the skills required for quality and quick replacement pipes at home is precise definition their diameter with the help of improvised means.

Whether it's problems with plumbing or plumbing in the bathroom or problems with the water supply in the kitchen, knowing how to determine the diameter of a pipe using available tools will come in handy.

Of course, there are special measuring instruments such as a circometer ruler, laser meter, etc. But things can be much easier.

Before making measurements, you should understand in what units they are made. It is generally accepted that such values ​​are always measured in inches (1 inch = 2.54 cm), and the standard size, for example, of steel products is most often 1 or 0.5 inches. By the way, the diameters of plastic, steel and metal-plastic parts differ.

The next step is to select the measured value. Outside is more important because it is on it that the threads are installed and threaded connections... This diameter directly depends on the wall thickness of the pipe. The dimensions of the wall thickness are determined by the difference between the outer and inner diameters of a given pipe.

Source: experttrub.ru

If the pipe is in your hands

If you need to measure the diameter with minimum accuracy requirements, and the cross-section of the product is fully accessible for measurements, then you can use a regular ruler or tape measure. The measuring tool is applied at the widest part and the number of divisions is counted. This method allows you to determine the outer diameter with an accuracy of a few millimeters.

A vernier caliper is used to measure products of small diameter. For this, the legs of the tool are applied to the end and tightly, but without effort, pressed against the outer walls of the pipe. The scale of the device determines the size of the diameter with an accuracy of tenths of a millimeter.

To calculate the inner diameter, the shear wall thickness of the pipe is measured. Subtract twice the wall thickness from the outer diameter to obtain the inner diameter.

Steel plumbing pipes are defined by their inner diameter, which is often measured in inches. How to find out the diameter of the pipe in inches, if this value is known in centimeters?

To do this, multiply the diameter in centimeters by 0.398. For the reverse translation, the diameter in inches is multiplied by 2.54... That is, the inside diameter of a pipe of one inch is 2.54 cm or 25.4 mm, and for example a ½ inch diameter is approximately 12.7 mm.

Source: vsetrybu.ru

If the pipe is built-in

When the end part of the product is inaccessible for measurement, for example, if it is an element of an existing gas or water supply system, it is necessary to act like this.

1. A caliper is applied to the side of the water pipe for measurements.
2. This method can be used to measure the pipe when the length of the tool legs exceeds half of its diameter.

How to measure a large pipe

It is very simple to do this, knowing the length of its circumference and the number π, which is approximately equal to 3.14.

1. First, measure the circumference of the pipe with a tape measure or cord to determine the circumference.
2. Next, substitute the values ​​you know into a simple formula: d = l: π, where the symbols mean: d is the diameter you are looking for, l is the circumference found.

For example: l is 31.4 cm. In this case d = 31.4: 3.14. We get 10 cm, which corresponds to 100 mm.

If the product is not available

When it is impossible to make direct measurements of the pipe for some reason, you can use the copying method.

1. For this purpose, attach a ruler to the pipe or small item whose linear parameters are known in advance. For example - a matchbox, the length of which is 5 cm.
2. Next, take a photo of this area.
3. Perform further calculations and measurements from the photo.
4. To do this, measure the apparent thickness (in mm) of the pipe in the picture.
5. Then translate the data you received into the actual dimensions of the product, taking into account the scale of the photograph.

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Determination of the outer and inner diameter of the pipe using improvised means

One of the skills required for high-quality and quick replacement of pipes at home is the accurate determination of their diameter using available tools.

Before making measurements, you should understand in what units they are made. It is generally accepted that pipe diameters are always measured in inches (1 inch = 2.54 cm).

Whether it's problems with plumbing or plumbing in the bathroom or problems with the water supply in the kitchen, knowing how to determine the diameter of a pipe using available tools will come in handy.

Of course, there are special measuring instruments such as a circometer ruler, laser meter, etc. But things can be much easier.

Before making measurements, you should understand in what units they are made. It is generally accepted that such values ​​are always measured in inches (1 inch = 2.54 cm), and the standard size, for example, of steel products is most often 1 or 0.5 inches. By the way, the diameters of plastic, steel and metal-plastic parts differ.

The next step is to select the measured value. Outside is more important because it is on it that threads and threaded connections are installed. This diameter directly depends on the wall thickness of the pipe. The dimensions of the wall thickness are determined by the difference between the outer and inner diameters of a given pipe.

Starting from words to deeds

In order to correctly measure both diameters, the peculiarities of all measurement methods should be taken into account, because each of them is suitable for different conditions.

One method is to measure the circumference of the part by wrapping it with a measuring tape or tape measure. Then the resulting value must be divided by Pi (3.14).

We need:

• ruler;
• calipers;
• tape measure (centimeter tape).

If access to the part area is not difficult and it can be measured before installation, then the most in a simple way will use a ruler or tape measure. The outside diameter is determined by placing a ruler at the widest part of the pipe and counting from the first outside point on the scale to the last.

There may be cases when measurements are already indicated in inches (imports). To convert to centimeters, the size is multiplied by 2.54, and for the reverse conversion to inches, by 0.398.

There is another way to determine the inner diameter if the pipe is directly accessible. With a caliper or ruler, the walls are measured along the cut, and then the resulting reading is subtracted from the measurements of the outer diameter and multiplied by 2.

If there is no direct access to the required site? One method is to measure the circumference of the part by wrapping it with a measuring tape or tape measure. Then the resulting value must be divided by Pi (3.14). Thus, we can find out the outer diameter of the pipe. This method also suitable if the length of a caliper or ruler is not sufficient.

There is a way to determine the outer diameter, which excludes all sorts of calculations, but only for those parts for which it is no more than 15 cm.To do this, you will need to measure the readings using only one caliper, on the scale of which the correct results are counted.

One of the most extraordinary ways is to compare the values ​​of the pipe with any object, photograph and further recognize the measurements. Take a ruler or any object, the length of which is already known in advance (a coin) and bring it to the area to be measured, and then take a picture. Further scaling on a computer will help determine the exact dimensions of the outer diameter. This method is ideal if it is impossible or extremely difficult to get close to the area being measured.

To measure the diameter of a pipe with minimal requests for accuracy itself, you can use a conventional construction tape. To start the measurement, you need to attach the measuring instrument to the widest point and count the number of the resulting divisions. This technique allows you to measure with an accuracy of a couple of millimeters.

For more accurate measurement of pipes of small diameters, a vernier caliper is mainly used. Before measuring the diameter of the pipe using this tool, it is necessary to attach its legs to the very end of the product and press lightly.

The resulting result will be visible on the scale of the device. The accuracy of such a measurement sometimes reaches tenths of a millimeter.

Measuring the inner section of a pipe

For this operation, it is necessary to measure the wall thickness according to the resulting cut of the product. To do this, you will need to subtract twice the wall thickness from the resulting value of the outer diameter. As a result of all the calculations performed, the value of the inner diameter of the product is obtained. Data on iron pipes calculated by the inner diameter, which is usually measured in inches. How, then, to determine the exact figure, if the value in centimeters is known?

This calculation requires the diameter known in centimeters to be multiplied by 0.398. The resulting result will just be the value you need.

If your product is mounted, and the end itself is not available for measurement, then a caliper again comes to the rescue. To measure, it is necessary to attach the legs of the unit to the side surface at the widest point. This measurement can be carried out if the length of the legs itself is more than half the diameter of the pipe being measured.

If the thickness of the pipe is quite large, then it is necessary to measure the circumference with a tape measure and divide by the number "pi" (3.14).

If for some reason there is no access to the pipes, then measurements can be made by copying. To do this, any object with previously known parameters is applied to the surface of the product itself and photographs are taken. Then, according to the obtained photograph, the necessary measurements are carried out. For this, the apparent thickness of the product is determined down to a millimeter. Further, the results obtained are translated into real size according to the scale of the survey.

Pipe size control in production

Pipes for construction or production, in mandatory must be supplied with appropriate certificates. This document indicates:

• Normative documents according to which they were produced.
• Delivery batch number.
• The brand of raw materials for the manufacture of products.
• Sizes in accordance with pipe standards.

At the end of the product, about 500 mm from the very end, a marking is applied. It indicates the very enterprise at which they were produced, the dimensions of the pipe and the date of its production.

All this is necessary, because when communications arrive at construction sites or production takes place measuring them geometric parameters... The length of the product can be measured with a tape measure or ordinary wire.

The diameter of the outside of the pipe is measured at the factory using a very complex formula. It is necessary to divide the circumference of this product by 3.14 and subtract double the thickness of the tape for measurement from the result.

To measure the ovality of the pipe, it is necessary to measure the cross-section of the end part using an internal gauge. This measurement must be carried out in two perpendicular planes.

Measuring the diameter of pipes is not a particularly difficult task, therefore, having necessary tool at hand, this operation will not be difficult.

Video

This video will show you how to use a caliper.

The home craftsman has to deal with the measurement of length, width and height all the time. An angle of 90 ° or 45 ° also often has to be maintained. Otherwise, it will not be possible to carry out high-quality repairs to an apartment or making homemade products. Accuracy when performing linear measurements of 1 mm is in the overwhelming majority of cases sufficient, and a tape measure or a simple ruler is suitable for them.

Often, tape measures have an additional bubble level, which allows you to place furniture, refrigerator and other items horizontally. But the accuracy of this level is not high due to the small length of the reference plane of the tape. In addition, the cone with the air bubble in the tape is often not positioned exactly, which does not ensure the horizontal position and the work done.

On sale, for measurement linear dimensions a wide range of laser measuring instruments are presented, but, unfortunately, due to the high price, they are not available to non-professionals.

Instructions
on the use of a caliper (columbus)

Calipers Is a linear measuring tool used to measure the outer and inner dimensions of parts, including the depth, with an accuracy of 0.1 mm.

The device and principle of operation of the vernier caliper

The classic vernier caliper is arranged as follows. A movable frame is installed on the measuring rod with the help of grooves. In order for the frame to sit tightly, a flat spring is installed inside and a screw is provided for its rigid fixation. Fixation is necessary when carrying out marking work.

The bar has a metric scale with a step of 1 mm and numbers indicate centimeter divisions. The frame has an additional scale with 10 divisions, but with a step of 1.9 mm. The scale on the frame is called the vernier in honor of its inventor, the Portuguese mathematician P. Nunis. The rod and frame have measuring jaws for external and internal measurements... A depth gauge ruler is additionally attached to the frame.

Measurements are taken with a clamp between the jaws of the part. After clamping, the frame is fixed with a screw so that it does not move. The number of millimeters is counted on the scale on the bar to the first vernier marks. Tenths of millimeters are counted according to the vernier. Whichever stroke on the count from left to right on the vernier coincides with any of the scale marks on the bar, so many will be tenths of a millimeter.

As you can see in the photo, the measured size is 3.5 mm, since from the zero scale mark on the barbell to the first vernier mark there were 3 full divisions (3 mm) and on the vernier it coincided with the risk of the barbell risk scale of the fifth vernier division (one division on the vernier corresponds to 0.1 mm measurements).

Caliper Measurement Examples

To measure the thickness or diameter of a part, you need to spread the jaws of the caliper, insert the part into them and bring the jaws in contact with the surface of the part. It is necessary to ensure that the planes of the jaws when closing are parallel to the plane of the workpiece being measured. The outer diameter of the pipe is measured in the same way as the size of a flat part, only it is necessary that the jaws touch diametrically opposite sides of the pipe.

In order to measure the internal dimension in a part or the internal diameter of a pipe, the caliper has additional jaws for internal measurements. They are brought into the hole and pushed all the way into the walls of the part. When measuring the inner diameters of the holes, the maximum reading is achieved, and when measuring in the hole of parallel sides, the minimum reading is achieved.

In some types of calipers, the jaws do not close to zero and have their own thickness, which is usually stamped on them, for example, the number "10", although the first risk of vernier is at zero. In the case of measuring the internal holes with such a caliper, 10 mm is added to the readings on the vernier scale.

Using a Columbus caliper with a movable depth gauge ruler, you can measure the depth of holes in parts.

To do this, fully extend the depth gauge ruler from the rod, insert it all the way into the hole. Bring the caliper rod all the way into the surface of the end face of the caliper, while not allowing the depth gauge ruler to come out of the hole.

In the photo, for clarity, I demonstrated the measurement of the hole depth by attaching a caliper depth gauge ruler with outside section of the pipe.

Examples of marking parts with a caliper

The vernier caliper is not intended for drawing marking lines on materials and parts. But if the jaws of a caliper for external measurements are sharpened on a fine-grained emery wheel, giving them a sharp shape, as shown in the photo, then it will be quite convenient to mark with a caliper.

Take off excess metal from the sponges you need to very carefully and slowly, avoiding the colors of the tarnishing of the metal of the sponges from strong heating, otherwise you can spoil them. To speed up the work, to cool the sponges, you can periodically dip them for a short time in a container of cold water.

To measure a strip sheet material with parallel sides, you need to move the jaws of the caliper, focusing on the scale at the specified size, with one sponge guide along the end of the sheet, and with the second scratch the line. Since the caliper jaws are hardened, they will not wear out. Can be marked as soft materials and solid (copper, brass, steel). Well visible risks remain.

With the help of the sharpened jaws of the caliper, you can easily outline a circle line. To do this, a shallow hole with a diameter of about 1 mm is made in the center, resting against it with one of the jaws, the second one draws a circle line.

Thanks to the refinement of the shape of the caliper jaws for external measurements, it became possible to accurately, conveniently and quickly mark parts for their subsequent machining.

How to measure with a micrometer in practice

You can get the size of products with an accuracy of 0.01 mm by performing measurements with a micrometer. There are many modifications of them, but the most common is a smooth micrometer of the MK-25 type, which provides a measurement range from 0 to 25 mm with an accuracy of 0.01 mm. It is convenient to use a micrometer to measure the diameter of the drill, the thickness of the sheet material, and the diameter of the wire.

The micrometer is a bracket, on one side of which there is a support heel, and on the other there is a stem and a high-precision thread into which the microscrew is screwed. The stem is marked with a metric scale, according to which millimeters are counted. The microscrew has a second scale with 50 divisions, according to which hundredths of a mm are counted. The sum of these two values ​​is the measured size.

In order to perform a measurement with a micrometer, the part is placed between the heel and the end of the micrometer screw and rotated clockwise by the ratchet handle (located at the end of the drum of the micrometer screw) until the ratchet makes three clicks.

On the stem, there are two scales with a step of 1 mm - the main one, digitized every 5 mm, and an additional one, shifted relative to the main one by 0.5 mm. The presence of two scales allows you to increase the tonality of measurements.

The readings are counted as follows. First, they read how many whole millimeters, not covered by the drum, were obtained on the digitized, lower scale on the stem. Next, check on the upper scale for the presence of risks located to the right of the risks of the lower scale. If the risks are not visible, then proceed to taking readings from the scale on the drum. If the risk is visible, then another 0.5 mm is added to the whole number of the resulting millimeters. The readings on the drum are measured relative to a straight line drawn along the stem between the scales.

For example, the size of the measured part is: 13 mm on the lower scale, on the upper scale there is no open mark, to the right of the open on the lower scale there is no need to add 0.5 mm, plus 0.23 mm on the drum scale, as a result of addition we get: 13 mm + 0 mm + 0.23 mm = 13.23 mm.

A micrometer with a digital reading of the measurement results is more convenient to use and allows you to measure with an accuracy of 0.001 mm.

If, for example, the battery runs out, then a digital micrometer can perform measurements in the same way as with a smooth MK-25, since there is also a reference system in divisions with an accuracy of 0.01 mm. The price of micrometers with digital readout of measurement results is high and for home master unbearable.

How to measure a large diameter pipe

Caliper jaws with a measuring range of 0 to 125 mm are 40 mm long and therefore allow you to measure pipes with an outer diameter of up to 80 mm. If you need to measure a pipe with a larger diameter or if you do not have a vernier caliper at hand, you can use folk way... Wrap the pipe around the circumference with one turn of a non-stretching thread or wire, measure the length of this turn using a simple ruler, and then divide the result by the number Π = 3.14. The photo shows a plastic ruler in the form of a triangle with angles of 45 ° and 90 °, with built-in protractor. With it, you can mark out and check the accuracy of the angle obtained.

When marking metal parts, a metalwork square is used, which provides more high precision measurements.

How to use the miter box

To obtain a straight line or an angle of 45º without marking, it is convenient to use a device called a miter box. With the help of a miter box, it is convenient to cut to size at an angle door frames, moldings, plinths and much more. The cut is obtained with the required angle automatically.

It is enough to measure the length, insert a strip of material between the vertical walls of the miter box and hold it with your hand to cut. Use a fine-toothed saw to get a good edge on the board. A hacksaw works well for metal. It is possible to cut even varnished boards without varnish chips.

An angle of 45 0 when sawing with a miter box is as easy as a straight one. Thanks to the high wall guides of the miter box, you can saw boards of different thicknesses.

You can buy a ready-made miter box, but it is not difficult to make it yourself from improvised material. It is enough to take three boards of wood or plywood of a suitable size, and screw the other two to the side ends of one of them with self-tapping screws. Make guide cuts at the required angles and the miter box is ready.