A caliper is a very popular measuring tool. The device of a caliper is quite simple, so almost everyone can use it without much preliminary preparation... It can be used to measure both the outer and inner dimensions of various parts, as well as the depth of the holes in them. In spite of simple design, this instrument has various accuracy classes and can give readings with an accuracy of 0.1 to 0.01 mm. It got its name based on the main design detail. Thanks to the device, the vernier caliper is rightfully considered one of the most versatile measuring tools.

Using a vernier caliper, you can measure both the outer and inner dimensions of various parts, as well as the depth of the holes in them.

Basic design characteristics of a caliper

A vernier tool, in principle, and a vernier caliper in this case, has a retractable rod with a measuring scale as the main part. This scale is divided into divisions of 1 mm, and its total length for the simplest household model ШЦ-1 is from 15 to 25 cm.There are also large models, but they are used only on industrial enterprises and are much less common. It is for this rod that the maximum value that this particular caliper model can measure is determined.

The digital vernier caliper ШЦЦ has a digital display mounted on a movable frame.

Its special design feature is the presence of such a device as a vernier. This is an auxiliary scale that is movable relative to the main ruler. It helps to correctly determine the number of divisions on this ruler. The divisions on the vernier scale, also known as "vernier", are a certain fraction less than the divisions of the main ruler. There can be 10 for a model with an accuracy of 0.1 mm, or 20 for models with an accuracy of 0.05 mm. The principle of operation of the vernier is based on the fact that it is much easier to determine the coincidence of divisions by eye than the relative position of one division between two others.

Measurement required external surfaces such as wire cross-section, large jaws are simply applied on both sides internal surfaces... The wire is clamped between them, and the zero scale division of the movable frame gives a reading on the main scale of the rod. Small jaws are shaped like scissor blades, which helps to measure the diameter of a pipe or other hole on a scale without additional calculations. They have external working surfaces with a sharpened blade profile, so they can measure such an indicator as the thread pitch.

Components and Applications

The tool consists of a fixed base and a retractable armature. They are made of tool steel. The caliper includes the following components:

1. The main bar to which all movable fittings are attached. It contains the main scale.
2. A movable frame with a screw lock and pressed by an inner spring plate. There is a vernier scale on it. It can be applied directly to it, or it can be on a plate fixed with screws. This allows it to be adjusted relative to the scale on the rod.
3. Exterior measuring sponges, or large sponges. One of them is fixed on a fixed bar, and the other on a movable frame. There are narrow surfaces at the ends, which gives additional features for measuring.
4. Internal measuring sponges, or small sponges. They are located according to the same principle opposite the previous ones along the central axis.
5. Ruler for measuring depths. Fixed to the movable frame.

The ruler for measuring the depth is fixed on a movable frame and moves along a groove made in the plane of the rod. It can also be used to measure internal grooves and shoulder distance. The bar is placed on the end perpendicular to the object being measured. The ruler extends until it rests against the bottom. For measuring tapered holes its end has a slight sharpening. After obtaining the measurement result, it is recommended to fix the position of the instrument with a locking screw, and only then take readings.

Varieties of design of calipers and their marking

Along with the simplest mechanical model, the device of which is discussed above, there are others. They can be divided into 4 main types, having 8 standard sizes... Their designs, like their purpose, have some differences. In addition to the above-mentioned double-sided caliper ШЦ-1, there is a one-sided version of ШЦТ-1. It has jaws on only one side and a ruler for measuring depths. Although it has a mechanical device, like ShTs-1, solid high-alloy steel serves as the material for its manufacture. Such a tool helps to determine the outer linear dimensions and the depth of the holes when abrading the measured object.

The tool called ШЦ - 2 is equipped with a double-sided design, but the jaws for measuring the inner and outer surfaces are aligned, and have, respectively, flat surfaces on the inside and cylindrical on the outside. Opposite them are jaws of the same size for measuring external dimensions, having sharpened edges. This allows you to make not only measurement, but also marking on the surface of the measured part. In addition, this model has an auxiliary micrometer feed frame that allows you to take readings with great accuracy.

Vernier caliper ШЦ - 3 differs from the previous model only in one-sided design. Its pair of jaws is designed to measure both inside and outside dimensions. This model is designed to measure the largest sizes, so it is also large enough. With what more sizes measuring device, the greater the error obtained during the measurement. Therefore, in addition to the structures described above, calipers are divided according to indicators with which readings are taken.

According to this principle, they are divided into vernier ones, on which the readings are calculated independently, based on the movement of the frame, into dial and digital. Dials marked with SCC use the same mechanical principle. On the frame there is a digital scale associated with the gear bar. Whole millimeters are read by the position of the edge of the frame, and their fractions are already read by the dial. Such a caliper has a higher accuracy class than a vernier caliper and can be up to 0.01 mm. However, it is very vulnerable to mechanical damage and contamination of the gear rack from the measured parts.

Turning production, installation of various piping systems, screw connections and other structures requiring increased accuracy are inextricably linked with the use of a caliper.

At the same time, thanks to the design, almost everyone can use it. The digital vernier caliper ШЦЦ has a digital display mounted on a movable frame. A reading device is mounted in the frame, showing the distance between the measuring jaws. The display has buttons that allow it to be operated. The accuracy of such a device is 0.01 mm and allows you to make measurements of the most small parts, in particular to control the thread. However, all the disadvantages of electronic devices are inherent in this instrument. Changes to boom parameters due to temperature extremes immediately affect the display readings.

In production construction works or minor repairs often require measuring tools. These are usually rulers or tape measures. But when measuring pipe diameter or hole depth, these tools are not suitable. For such purposes, more accurate measuring instruments are used - vernier calipers.

Such a device is versatile. It can be used to measure the external and internal dimensions of parts. Calipers have gained wide popularity in everyday life, as it has a simple device and is easy to use. With such a device, you can quickly and easily measure with high accuracy.

Caliper device

1 - Jaws for internal measurements
2 - Sponges for external measurements
3 - the Clamping screw
4 - Moving frame
5 - Nonius
6 - Bar
7 - Barbell scale
8 - Depth gauge

All instruments similar to calipers have a measuring rod, thanks to which the device received this name. There is a main scale on the rod, which is necessary when measuring in the first place.

A movable frame with a printed scale has the ability to move along the rod. The scale on the bar is called the vernier, which has a more accurate marking by divisions. This provides increased measurement accuracy. The degree of accuracy of the caliper, depending on the version, can reach hundredths of a millimeter.

Calipers have two types of jaws:

• For measuring internal dimensions.
• For measuring outside dimensions.

There is also another measuring element of the device, which is called a depth gauge. It can be used to measure the depth of holes and other dimensions.

Digital calipers work in a similar way. However, instead of vernier, a digital scale is used, which increases the ease of use and measurement accuracy of the device.

1 - the Clamping screw
2 - Battery
3 - Length change roller
4 - Zeroing
5 - On / Off
6 - Switching mm / inches

Like all measuring instruments, digital instruments are equipped with a scale with a graduation of 0.01 mm. The permissible error is the deviation of the measurement result up or down by 10%. In industry, all measuring instruments are subject to metrological control every six months.

The trade network sells calipers packed in a case. When purchasing a tool, it is recommended to inspect the measuring jaws. They should be flat and there should be no gap when they are compressed.

The vernier scale should be in the zero position when the jaws are closed. The vernier scale division lines must be clearly marked. The set of the device must include a passport with a note about the verification performed for accuracy.

Types and features

The main types of calipers:

There are several subspecies of different calipers, depending on the size, design features and the principle of action. Below we will consider the main types of such measuring instruments.

ШЦ-I

This is the simplest and most popular model of the device, which is widely used in industrial production. It is called "Columbic" after the name of the manufacturer that produced the instrument in war time(Columbus).

The device can measure internal, external dimensions, depth. The measurement interval is from 0 to 150 mm. The measurement accuracy reaches 0.02 mm.

ШЦЦ-I

This digital model of the measuring tool has a similar design to the classic caliper. Measurement interval 0-150 mm. One of its advantages is higher measurement accuracy due to the presence of a digital indicator.

The convenience of using such a digital device is that the indicator can be zeroed at any point of measurement. It is also easy to switch the metric system to inch with one button.

When buying a digital model, you need to pay attention to the presence of zero readings when the jaws are flattened, as well as when the locking screw is tightened, the numbers on the display should not jump.

ShTsK-I

In such a design of the caliper, there is a rotary indicator with a circular scale, the division of which is 0.02 mm. It is convenient to use such calipers for frequent measurements in production. The indicator arrow is clearly visible for quick control of the result, does not have jumps, unlike digital models. This device is especially convenient for use in the technical control department for measurements of similar typical dimensions.

ШЦ-II

Such rulers are used for measuring internal and external dimensions, as well as for work on marking parts before processing. Therefore, their jaws have carbide tips to protect them from rapid wear. The measurement interval of the ShTs-II series of devices is within the range of 0-250 mm and the measurement accuracy is 0.02 mm.

ШЦ-IIIand ШЦЦ-III

Large parts are most often measured with such a tool model, since its measurement accuracy is higher than other models and is 0.02 mm for mechanical devices, and 0.01 mm for digital.

The largest dimension for measurement is 500 mm. The jaws in such models are directed downward, and can have a length of up to 300 mm. This makes it possible to measure parts within a wide range.

Special purpose calipers

We will briefly consider several specialized models of calipers designed for special types works. Such devices appear quite rarely in the retail network.

• SCCT- used for measuring pipes, it is called a pipe caliper.
• ШЦЦВ- for measuring internal dimensions, has a digital display.
• SHTsN- similar to the previous device, it is used to measure external dimensions.
• SCCU- a universal digital meter, the kit includes a set of nozzles for hard-to-reach measurements: center-to-center distances, pipe walls, external and internal dimensions, etc.
• SCCD- a device for measuring the thickness of brake discs and parts with various protrusions.
• ShTsPP- Calipers are used to measure the tread depth of car tires.
• ШЦЦМ- vernier calipers, designed specifically for measuring center-to-center distances.

Rules for using a caliper

• Check tool. To do this, bring the jaws of the caliper together and check the accuracy of their closure for the presence of a gap between them.
• Take the tool in your right hand and the workpiece to be measured in your left hand.
• To measure the external dimension of a part, it is necessary to spread the lower jaws of the tool and place the part to be controlled between them. In this case, you should be careful, as the edges of the jaws are sharp, and you can get injured if you handle the instrument carelessly.
• Squeeze the jaws of the caliper until they come into contact with the workpiece. If the material of the part has a soft structure, then strong compression of the jaws will lead to an inaccurate measurement. Therefore, the jaws must be squeezed carefully, only until they come into contact with the surface of the part. Use your thumb to move the caliper frame.
• Check the position of the jaws in relation to the part. They should be at an equal distance from the edges of the part, the presence of distortions of the tool is not allowed.
• Fix the screw for clamping the movable frame. This allows you to maintain the position of the frame for accurate measurement results. It is advisable to tighten the screw with a large and forefinger, at the same time, with the same hand, hold the instrument in one position so as not to move it to ensure measurement accuracy.
• Place the part aside, and take the fixed caliper without the part to take the measurement results.
• The step of taking readings from the instrument is very important, since inaccuracy in the measurement can lead to serious consequences in production.

Place the caliper directly in front of your eyes.

1 - Barbell scale
2 - 21 divisions
3 - Vernier scale

The figure shows the order of measurement. The jaws for external measurements with the measured part are shown on the left, and the scales are shown on the right: vernier and main. Their divisions determine the measurement result.
First, you need to count the number of whole millimeters. To do this, you need to find on the barbell scale the division that is closest to the vernier zero. This division is indicated by the first upper red arrow. In our case, this value is 13 mm. This value must be remembered or written down.
Next, you need to calculate the fractions of a millimeter. To do this, on the vernier scale, you need to find the division that coincides with the division on the barbell scale. This division is shown in the figure by the second red arrow.
Next, you need to determine the division number in order, for our case it turns out 21.
Then you need to multiply this number by the price of division of the vernier scale. In our example, the graduation is 0.01 mm.
Now you need to calculate the exact value of the measurement determined by the caliper. To do this, add an integer with fractions of a millimeter. The result is 13.21 mm.

• At the end of work with the tool, clean it, loosen the screw, close the jaws and put it in the case. If the tool will be stored for a long time, it is recommended to treat it with an anti-corrosion solution.

With a dial or digital caliper, the measurement process becomes much easier, since you do not need to calculate anything, the finished result will be visible on the display or on the dial.

Is universal measuring device to determine the linear dimensions of parts with a specified accuracy. It can be used to measure the outer and inner dimensions of parts, as well as the depth of the holes, provided there is a retractable rod.

The device and application of calipers

The most popular areas of application of the caliper are construction, repair of machinery and equipment, processing of metal and wooden products... The scope of application actually has no restrictions - it can be used to determine dimensions with an accuracy of 0.1 or 0.05 mm (depending on the type of instrument) in any field of activity - both in everyday life and in the aerospace industry. Application possibilities are limited only by the scale size and accuracy requirements (up to 0.01 mm for electronic calipers).

The device of the caliper is quite simple. The main element is a fixed bar with a scale and jaws for external and internal dimensions, to which movable and fixing elements are attached.

• Movable frame;
• Movable jaws for determining the internal size;
• Movable jaws for determining the outer size;
• Vernier scale;
• Depth gauge rod;
• Screw for fastening the frame.

In some models, there is a movable scale in the upper part with an inch measuring system.

How to take readings with a caliper

Before starting work, it is necessary to check the caliper for accuracy. To do this, it is necessary to completely reduce the lips and check the coincidence of zeros on both scales. If there is no coincidence, then, depending on the required accuracy, it is necessary either to take another tool, or to take into account the existing error.

• To measure the external dimension, spread the jaws of the caliper, place the object and connect them.
• The internal dimension is measured by placing the corresponding upper jaws inside the measured area and spreading them all the way
• The jaws should rest against the edges of the part. If the surface is hard, then you can squeeze a little for a tight fix, for soft this should not be done, since you can distort the result.
• Check the alignment of the caliper relative to the workpiece for misalignment. To do this, the jaws must be at the same distance from the edge of the part.
• Fix the vernier with the fixing screw.
• Determine the whole number of millimeters on the main scale.
• We find the coincidence of the stroke on the vernier with the zero of the main scale and count the number of divisions.
• We multiply the number of vernier divisions by the division price and add up with the value of the main scale.

Types of calipers

In general, all types of calipers can be divided into mechanical and electronic, depending on the type of scale. The main types, according to GOST 166-89, are:

• ШЦ-I - a tool with 2-sided placement of jaws for measuring external and internal values ​​and a depth gauge.
• ШЦК - equipped with a dial to determine the exact size. Easier to use than vernier calipers.
• ШЦТ-I - one-sided jaws for measuring external linear dimensions. Differs in high wear resistance.
• ШЦ-II - equipped with two jaws for external and internal measuring and marking, as well as a micrometric feed frame.
• ШЦ-III - one-sided jaws for determining external and internal dimensions.
• ШЦЦ - electronic vernier caliper with digital display.

Technical condition and calibration of the caliper

One of the most important requirements for instrument accuracy is cleanliness. A magnetized layer of metal filings, preservative grease, dirt - all this can significantly distort the measurement result. Also, the result is influenced by tool wear, its deformation, and violation of settings. To avoid this, an annual calibration of the caliper is required by a specialized service center renovated and adjusted. The simplest check of the correctness of the readings is the coincidence of zero lines when the jaws are completely closed.

Current GOSTs

The production and verification of the instrument is regulated by a number of state standards... So, defines the technical conditions for calipers GOST 166-89. The procedure for checking the instrument is defined in GOST 8.113-85.

In a home workshop, in addition to a variety of measuring tools, there should be a caliper, which is often needed where a tape measure or ruler does not fit.

Below we will consider what a similar measuring tool, what types are found and how to use it correctly in order to get the most accurate measurement data.

Purpose of the caliper

This measuring tool is mainly used to obtain the most accurate data when determining the outer and inner diameters of pipes, the thickness of their walls, to calculate the center distance in the holes, the dimensions of cylindrical parts, the thickness of the wire and sheet metal, as well as other materials of small dimensions and small products.

Such a device is convenient to measure the depth of grooves, holes and grooves, various grooves with great accuracy in the most hard-to-reach places... The accuracy of a caliper during measurements reaches tenths and hundredths of a millimeter, which cannot be provided by such a simple instrument as a ruler or tape measure.

The tool, according to GOST 166-89, is made of stainless or carbon steel coated with a chrome-plated compound. Comprises:

• a rigid metal ruler called a barbell (hence the name of the tool - a vernier caliper);
• measuring protrusions - jaws;
• an auxiliary frame with a vernier scale, otherwise called vernier, which allows measurements to be made with an accuracy of tenths and hundredths of a millimeter, depending on the type of instrument;
• a movable depth gauge ruler rigidly connected to the jaws.

The scale of the vernier caliper can have different lengths and the number of divisions. 10 divisions on the vernier scale make it possible to measure with an accuracy of 0.1 mm, 20 divisions give a measurement accuracy of up to 0.05 mm:

The jaws can be upper and lower. On the surface of the lower ones - indicated minimum size parts to be measured. The ends of the lower jaws are made in the form of rectangles. The upper ones are pointed and beveled vertically, which allows them to mark out on any materials and details, without using other marking devices (that is, you can draw a line exactly in size with sharp ends directly with sponges).

With the help of the upper jaws, the internal dimensions of the holes, the diameters of the pipes, grooves, and various recesses are measured. The bottom jaws are used to measure external parameters. To measure the length of deep holes, use a depth gauge ruler that extends from the main rod:

To fix the movable frame with the vernier scale on the ruler, there is a special fixing screw. Some models of calipers are equipped with a circular scale and a movable frame, the scale of which is designed for measurements in inches. At the same time, the vernier scale of such a device allows measurements to be made with an accuracy of 0.128 inches.

Caliper types and specifications

The classification of such measuring instruments is carried out according to several parameters - the method of taking readings, the type of scale, the location of the jaws. All these differences are reflected in the labeling of the device.

Have different types Calipers for taking measurements can use the following types of scales:

1. scale "vernier";
2. scale located on the dial;
3. using a scoreboard with a digital indicator.

By their design, calipers are divided into the following types:

• Single-sided tools made of carbide steel and marked with ШЦТ.
• Mechanical models with one- or two-sided arrangement of jaws, marked as ШЦ-I, ШЦ-II, ШЦ-III, on which measurements can be read using a vernier scale.
• A device equipped with a dial is marked with SHIK or ShTsK and allows more accurate measurements than devices with a vernier scale. On the dial, fractional readings are shown, on the bar itself, integers.
• The latest generation electronic vernier caliper with a digital display showing the distance between the inner surfaces of the jaws is marked with SCC and can work in symbiosis with a PC. This is the best device that allows you to quickly, without unnecessary calculations, see the measurement data, which are carried out with a high accuracy of 0.01 mm.

The ShTs-II tool differs from the ShTs-I model in that it has an additional frame equipped with a locking screw and connected to the main frame. The fixed additional frame allows you to bring the ends of the jaws for more accurate measurement of the internal dimensions of the holes.

The ShTs-III device differs from the ShTs-II model in that it does not have one pair of upper marking jaws. Used for measuring large parts.

How to use a caliper correctly

Before using the tool, you must check it for serviceability and accuracy. To do this, you need to inspect it and remove the existing dirt on all parts. It is also necessary to check whether the zero marks on the main scale and the vernier scale coincide with the tight connection of the lower jaws.

It is best to fix the part to be measured in a stationary state, but you can also hold it in your left hand, the main thing is not to allow its mobility during the measurement process. If you want to measure external dimensions any part, you need to dilute the sponges and tightly cover the measured object with them. In this case, the part must be in the correct position, without skewing and must not move. The next step is to fix the part in the caliper by screwing in the fixing screw, without undue effort. Only then can you start reading the readings.

When using the SCC device, you do not need to calculate the dimensions of the measured part, all this is shown on the display. It is also not difficult to take measurements when working with the ShTsK device. Whole numbers on the bar are indicated by the edge of the movable frame, hundredths or tenths of a millimeter are indicated by a dial.

But with a mechanical tool ШЦ-I, ШЦ-II and ШЦ-III, it will be necessary to compare the values ​​of the main scale and the vernier one. First, the size in whole numbers is determined, that is, the readings on the main scale, which is determined by the position of the first risks of the vernier scale. Then, depending on the type of caliper, the size is determined in tenths or hundredths of a millimeter.

Total, Algorithm of measurements:

1. We look at the upper scale, how many whole millimeters fit.
2. On the lower scale, we look at which division coincides as much as possible with the division on the upper scale (as if it turns into one line) - these are tenths and hundredths of a millimeter.

Consider in the picture how a measurement of 28.55 millimeters is obtained:

When using the tool, you should take into account the error of the caliper, which may arise due to improper storage, mechanical damage, contamination of the tool, and the temperature state of the measured workpiece. Optimum temperature for measurements this device has a range of 10-40 degrees above zero. To obtain the most reliable measurement data when working with a caliper, it is recommended to take several measurements and calculate the arithmetic mean. At the end of the measurements, the device must be wiped dry and stored in a case.

This concludes the article. Today we learned what a caliper is, what types it is and how to make measurements with it.

No plumbing work is complete without measuring a particular part. Many products or some operations in the process of execution require control. One of the most universal remedies is a vernier caliper (shts, caliper).

This tool is necessary not only in the engineering industry, but also in household when repairing a car, household appliances... It can be used to measure linear dimensions such as bearing diameters. It is a convenient and accurate instrument.

Many in their lives have faced the need to use this meter, but most do not know how to use it correctly. How to accurately measure with this device?

For proper use and understanding, it is necessary to familiarize yourself with the device. All calipers, regardless of their type, class and measurement accuracy, consist of the following elements:

Calipers are different types... Depending on the measurement limit: shts-1, shts-2, etc.

By layout type:

• vernier (common, most common and cheapest);
• electronic (on the moving part - a liquid crystal display showing the measurement results);
• arrow or dial (have a "clock" mechanism on the moving part).

In mechanical engineering and aircraft construction, there are special rods. They differ from ordinary shts with special sponges.

Correct use of a caliper

Before starting work, it is necessary to determine the integrity and serviceability of the measuring tool. The lower jaws must be tightly closed without gaps, notches or distortions.

In this position, the zero marks of the rod and the vernier must completely coincide. There should be no dirt, corrosion or nicks on the surface of the bar.

If necessary, wipe with a clean cloth not only the rod, but also the surface to be measured, otherwise this may affect the measurement error. Next, let's take a closer look at how to correctly measure with a caliper

How to use a caliper 0.1 mm, shts-1

The caliper must be taken in the right hand, spread the jaws to the required length using thumb(there is a grooved protrusion on the movable bar for this). The jaws must fit tightly to the surface to be measured, without distortions.

Strong effort is not needed. The contact of the jaws should be light and completely tight. Next, we look at the indicators. The first division of the vernier shows, for example, more than 7 mm, but does not reach 8. So, we are looking for a match on the vernier scale. Suppose you found a match at the fifth division. This means the size is 7.5 mm.

When measuring, it is not necessary to tighten the fixing screw too much, as this may confuse the true size. You need to correct the backlash at the beginning of work, if necessary. A rigidly fixed body with a vernier is required for marking.

To measure the depth, it is necessary to bring the end of the barbell to the edge of the part. The butt should fit snugly, without skewing. Thumb right hand it is necessary to bring the depth gauge into the hole until it stops against the wall. The tip of the device should lightly touch the bottom. In this case, the extrusion of the end of the rod must not be allowed. If necessary, you can fix the movable bar with a screw and read the readings, as with other types of measurement.

By following these tips, the measurement accuracy will be greatly improved. They are suitable for all types of SC.

Care and storage rules

After work, the vernier caliper must be wiped, cleaned of dust and dirt. It is best to store in the original box with which the device is sold.

It is better to keep the device in a dry and dark place, protecting it from drops and mechanical impact. Careful and careful handling will allow you to use the measuring tool for many years.