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

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

Purpose of 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 parts cylindrical shape, thickness of wire and metal sheet, as well as other materials of small dimensions and small products.

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

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

• a rigid metal ruler called a barbell (hence the name of the tool - caliper);
• measuring protrusions - sponges;
• an auxiliary frame with a vernier scale, otherwise called a 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 vernier caliper scale can have a different length and number of divisions. 10 divisions on the vernier scale make it possible to measure with an accuracy of up to 0.1 mm, 20 divisions give a measurement accuracy of up to 0.05 mm:

Sponges can be upper and lower. On the surface of the bottom - the minimum size of the measured parts is indicated. 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 on any materials and parts, without the use of other marking devices (i.e., you can draw a line exactly in size with sponges directly due to sharp ends).

Measurements are made using the upper jaws internal dimensions holes, pipe diameters, grooves, various recesses. The lower jaws are used to measure external parameters. For measuring length deep holes a depth gauge ruler is used, which extends from the main stem:

To fix the movable frame with a vernier scale on the ruler, there is a special fixing screw. Some models of calipers are equipped with a scale round shape and a movable frame, the scale of which is designed to take 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.

At different types calipers for taking measurement readings, the following types of scales can be used:

1. vernier scale;
2. scale located on the dial;
3. using a digital display board.

According to their design, calipers are divided into the following types:

• Single-sided tools made of carbide steel and marked with ShTsT.
• Mechanical models with one- or two-sided arrangement of jaws, marked as ShTs-I, ShTs-II, ShTs-III, on which measurements can be taken using a vernier scale.
• A device equipped with a circular scale is marked SHIK or SCC and allows more accurate measurements than devices with a vernier scale. Fractional readings are shown on the circular scale, whole numbers on the bar itself.
• Electronic caliper latest generation with a digital display showing the distance between internal surfaces sponges, is marked 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 up to 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. Fixed additional frame allows you to bring the ends of the jaws for a 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, it is necessary to check it for serviceability and accuracy. To do this, you need to inspect it and remove the existing contamination 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 measured part in a stationary state, but you can also hold it in your left hand, the main thing is to prevent its mobility during the measurement process. If you want to measure the external dimensions of any part, you need to dilute the sponges and tightly cover the object being measured with them. In this case, the part must be in the correct position, without distortion and must not move. The next step is to fix the part in the caliper by screwing in the mounting screw, without undue force. Only after that you can start reading the testimony.

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 dimensions when working with the SCC device. Integer numbers on the rod are indicated by the edge of the movable frame, hundredths or tenths of a millimeter are shown by a circular scale.

But with a mechanical tool ShTs-I, ShTs-II and ShTs-III, it will be necessary to compare the values ​​​​of the main scale and the vernier. First, the size is determined in integers, i.e., the indication on the main scale, which is determined by the position of the first risk of the vernier scale. Then, depending on the type of caliper, the size is determined in tenths or hundredths of a millimeter.

Total, Measurement algorithm:

1. We look at the upper scale, how many whole millimeters fit.
2. On the lower scale, we look at which division maximally coincides 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 the measurement of 28.55 millimeters is obtained:

When using the tool, you should take into account the error of the caliper, which may occur due to improper storage, mechanical damage, tool contamination, temperature state of the measured part. Optimum temperature for measurements, this device is a range within 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 is where the article ends. Today we learned what a caliper is, what types it is and how to use it to make measurements.

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Help the toolmaker

Inspection and repair of caliper tools

Malfunctions of calipers and their check.

Most typical malfunctions caliper tools, as a result of which the accuracy of readings is violated, are: wear of the measuring surfaces and blunting of the sharp ends of the jaws; wear and deformation of the working surfaces of the rods and the frame; skew of the main frame; incorrect installation of the vernier; spring weakening; wear of the thread of the screw and nut of the micrometric feed, and a number of others. n The readings of caliper tools with a reference value of 0.05 mm are checked using gauge blocks of the 2nd accuracy class (6th category), and with a reference value of 0.1 mm - end blocks of the 3rd class.

The skew of the movable jaw is relatively immobile and is also detected with the help of an end measure of length.

Having set the end measure in two extreme positions, take readings and, by their difference, judge the magnitude of the non-parallelism of the measuring surfaces caused by the skew of the movable sponge.

The wear of the measuring surfaces is determined by the magnitude of the discrepancy between the zero strokes of the rod and vernier scales with tightly shifted jaws. For caliper tools with a reading of 0.02 and 0.05 mm, the clearance between the measuring surfaces should not exceed 0.003 mm, and for caliper tools with a reading of 0.1 mm - 0.006 mm. On fig. 79.6 shows how, with the help of end measures and a curved ruler, it is possible to determine the size of the gap between the measuring surfaces by eye.

Rice. 1. Checking the calipers.

The scheme for checking the wear of the working surfaces of the sponge for internal measurements is shown in fig. 1, e. Between the jaws for external measurements, a limit measure is placed, and then, using another caliper, the distance between the jaws for internal measurements is checked. This distance must be equal to the size of the gauge block.

The wear of the rod is set with a curved ruler to the light.

Repair of calipers. The wear of the working surfaces of the caliper tools is eliminated by straightening the jaws with their subsequent fine-tuning. Straightening also eliminates defects in the measuring surfaces of the jaws and matches the zero strokes of the scales. After straightening, they start finishing the measuring surfaces with plane-parallel laps, for which the caliper is fixed in a vice, the lap is placed between the jaws, and the frame is shifted until the jaws come into contact with the lap. In this position, the Frame is fixed with a locking screw and, moving the pri-r between the jaws with a slight effort, R finishes the surfaces from the side of both sharp and blunt jaws until flatness, parallelism and the same size of the solution on both sides are achieved.

Rice. 2. Fine-tuning of the measuring surfaces of the caliper.

The straightness of the measuring surfaces is checked with a curved ruler, and the parallelism of the jaws of the frame with the jaws of the rod and the dimensions between them are controlled by end measures, while the force with which the measure is inserted between the jaws must be the same for both sides. By inserting the end measure not from the end of the jaws, but from the side along the entire plane and at the same time slightly turning it, you can determine the degree of parallelism of the surfaces. If the tile is delayed by the ends of the jaws, freely rotating further over the entire surface, or if there is a gap in front, then the jaws are not parallel.

The outer surfaces of blunt jaws are brought to parallelism. The size of the jaws should be equal to a whole number of millimeters with tenths (for example, 9.8 mm). After finishing the sponges, the vernier is set to zero division of the rod. To do this, the jaws are shifted until the measuring planes touch and the movable frame is clamped. Then the vernier is moved until the first and last divisions coincide, while its scales must exactly match the first and corresponding divisions of the bar. In this position, the vernier is fixed.

When repairing a large number calipers finishing of measuring surfaces can be mechanized. The scheme of mechanized finishing is shown in fig. 2b. A complex zigzag movement during mechanical finishing is formed as a result of two movements: the horizontal reciprocating movement of the lap 1 (at i = 400 strokes / min and a stroke length of 23 mm) and the vertical translational movement of the caliper 2 (periodic feed movement 5 = 1, 5-3 m / d. stroke. lap). To ensure the quality of finishing, both movements are coordinated with each other. The caliper only receives vertical movement when the lap moves. At half the stroke of the lap at maximum speed, the caliper is also given a small amount of vertical feed. At the extreme points of the path of the lap, where its speed is zero, the vertical feed of the caliper stops. Finishing pressure should be P-2-3 kg/cm2.

When mechanically finishing the jaws of the caliper, cast-iron laps are used, cartoonized with M20 micropowder.

Repair of lightweight calipers in case of breakage of sponges is carried out in the following order. After tempering in a salt bath, the worn or broken end of the sponge is cut off. Then, in the thickened part of the leg, a groove is cut with a disk cutter, equal in width to the thickness of the sponge. A new sponge blank is inserted into the groove of the leg and two or three holes are drilled together, then both parts are riveted. Sponges are sawn to the specified dimensions and hardened. After stripping, their measuring surfaces are finished.

Rice. 3. Caliper repair.

If both jaws break, the upper leg is completely replaced with a new one. To do this, knock out the rivets and remove the broken leg from the rod. In the blank of a new leg, a rectangular window is milled and filed, equal in shape and size to the end of the rod. Then a leg is put on the rod, the perpendicularity of its position relative to the faces of the rod is verified, holes are drilled in another place and the leg is riveted. The jaws are filed so that their configuration and dimensions correspond to the shape of the frame jaws, and then they are finished.

The broken sponges of the frame are replaced with new ones, for which, having knocked out the rivets and removing the unusable sponge, a blank of a new sponge is riveted in its place, filed, hardened and brought to a finish.

The repair of broken jaws of stamped-bar calipers is somewhat more difficult, since the entire stem, together with the jaws, has the same thickness and it is impossible to insert a new jaw. Overlay riveting does not always provide sufficient bond strength. You can use welding, but it is best to replace the entire upper part rods by installing a new leg.

For this purpose, after annealing and cutting off the jaws, the end of the ruler is milled or filed by hand so that shoulders are formed on the edges of the ruler, against which the leg rests. When filing the measuring planes of the jaws of the legs, it is necessary to ensure that the zero division of the vernier of the frame approximately coincides with the zero division of the scale on the ruler, since with a significant displacement of the vernier at its end, too much metal will have to be removed, which will worsen the quality of the repair.

Rod deformation can be caused by warping or uneven wear of its working surface. The bending of the rod is eliminated by straightening, carried out by bending in a vice with the help of three narrow brass washers.

Uneven wear of the rod is eliminated by sawing and finishing on the lapping plate, controlling the straightness with a curved ruler or the paint method. Dents and nicks are cleaned with a velvet file, a whetstone and fine sandpaper with oil.

To eliminate the misalignment of the vernier with the scale of the ruler, it is rearranged. If the end of the vernier rests against the wall of the frame window and cannot be moved, then it is filed. At the same time, the holes for the screws are also sawn, after which, by rearranging the vernier, they fix it in the correct position.

Repair of other universal measuring instruments (goniometers, gage gauges and gage gauges) is similar to the repair of calipers.

The main defects of the depth gauge can be the non-straightness of the supporting surface, the lack of perpendicularity of the ruler relative to the reference plane, and incorrect installation of the vernier.

To ensure the straightness of the supporting plane of the body and the end of the ruler, they are brought together on a plate. Having extended the ruler above the plane of the body, using a curved square, check its perpendicularity relative to the reference plane.

Repair of the vernier is done in the same way as the vernier caliper. When setting the ruler to a certain size, its end is combined with the plane of the depth gauge. In this position, the zero division of the vernier is combined with the zero division of the scale of the ruler or with the division corresponding to the height of the set of gauge blocks, after which the vernier is fixed with screws.

The reliability of measuring instruments depends on the accuracy of their manufacture and fit of the main parts. As the tool wears out, it is necessary to repair it, eliminating the curvature of the guide ribs of the rod, non-parallel or non-perpendicular working surfaces of the jaws, skew of the frame, etc.

The working surface of the rods of the caliper tools is checked by the paint on the calibration plate; irregularities are cut down with a personal file and adjusted on a lapping cast-iron plate. In this case, it is necessary to maintain the parallelism of the ribs within 0.02-0.03 mm. The measuring jaws of the front of the gauges and the base of the gauges must be machined at an angle of 90°.

ron. Then they drive the rivets into the holes and rivet them flush with the surface of the cheeks. Having fixed the jaws on the rod 3 and frame 9 and making sure that they are rigidly installed in the grooves, they are sawn and cleaned along the entire contour, while checking with a control square the perpendicularity of their working surfaces to the surface of the rod rib. Having filed and cleaned all the outer surfaces, as well as the working surfaces of the sponges, they are thermally treated to a hardness of HRC 56-58 and released by 2-3 units. After that, the outer surfaces of the frame and jaws are carefully cleaned, installed and fixed with screws in the vernier 4 frame, springs are inserted into the collar and frame and put on the rod 3. Caliper in assembled fixed in a bench vise and proceed to fine-tuning the measuring planes of the sponges.

When finishing the measuring planes of the jaws 6 and 7 (Fig. 145), the caliper should be checked with a square to check their perpendicularity to the plane of the rod 3. The parallelism of the ribs of the rod and the planes of the jaws is checked using end measures clamped
screws between the measuring planes when moving the frame every 10 mm of the rod length.

When moving the frames with sponges along the rod 3, the pressing force of the measuring planes of the sponges on the end measures must be the same everywhere. The measuring planes of the jaws are adjusted using three cast-iron laps, differing from one another in height by 0.25 mm. The laps are periodically adjusted and lubricated

Rice. 146. Method of checking pa - Fig. 147. Desktop stamp for

parallelism of the planes of the bending jaws of the leaf springs to

caliper with caliper tool

gauge block tiles

yut with 10-12 micron GOI paste moistened with kerosene. When assembling the caliper assemblies, it is necessary to pay Special attention the operation of the plate springs inserted into the grooves of the frame and the clamp, since not only the smoothness of the movement of the frame along the tool rod, but also the accuracy of controlling the outer and inner dimensions of the part with measuring sponges largely depends on them.

The planes of the rod ribs can be considered parallel to each other and perpendicular to the measuring planes of the jaws in the case when these planes come into contact with the cast block of end measures and sharp jaws 7 and 8 and blunt jaws 5 and 6, the readings of the caliper will be the same.

When checking the parallelism of the planes of the jaws in the process of finishing them, it is necessary to ensure that the screws 7 and 8 (Fig. 146) only slightly clamp the springs in the frame 2 and the clamp 9. This is done so that the frame and clamp move freely along the rod without distortion 1. At the same time, grabbing the collar 9 and frame 2 with the right hand, the patterner should only move them along the rod, and with the left hand, grabbing the tile of end measures 10, slightly shake it between the planes of blunt jaws 3 and 4 and sharp jaws 5 and 6.

By moving the tile along and across the planes of the jaws, they check not only the parallelism of their planes to each other, but also the fit of the planes of the tile W to the processed planes of the jaws of the caliper.

On fig. 147 shows a diagram of a desktop hand stamp
for bending blanks of plate shaped springs made of steel 65G for caliper tools. The matrix 2 of the stamp is clamped in a vice 1 and the workpiece of the plate spring 3 is placed in it, then the shank 6 of the stamp is grabbed with the left hand and the punch 5, connected to the shank by pins 8, is pressed against the stop bar 4, fixed on the matrix 2 by screws 7. Then, with the hammer handle, it is easy hit the shank 6 of the die. The result is the desired shape of the leaf spring, length L. Die dimensions

performed depending on the length of the frames and clamps of the caliper tools.

On fig. 148, and shows the method of correcting the curvature of the parallel side surfaces of the rod 2, fixed in a bench vise 1 between three aluminum spacers 3. In the process of editing, the rod is moved along the spacers 3 with the left hand, and with the right hand, turning the handle 4 of the vise and lightly pressing on the spacers, correct rod curvature. On fig. 148b shows another way to correct the curvature of the rod 2, sandwiched between the aluminum spacers 5 in the vise jaws. Unlike the previous method, the curvature of the rod is corrected across its side planes with the help of a forked mandrel 6.

The device shown in fig. 149, designed for grinding and pripilovki surfaces of caliper rulers. In the groove of the base 1, a ruler 3 is placed on the set screws 2 until it stops in the pin 4 and clamped on both sides and from the end with screws 5 and 6. Using the indicator, check the parallelism of the surface, after which the fixture is fixed with a thickened end

tanavlyayut on the electromagnetic plate until it stops. After sanding the surfaces of the ruler and sponge on one side, grinding wheel lift and, without changing the setting of the device, turn the ruler over and grind the surfaces on the other side. Then the caliper is assembled and the planes of its jaws and the movable frame are adjusted.

When repairing the gage gauge (Fig. 150, a), it is necessary to ensure that the rod is perpendicular to the base. Therefore, before straightening the rod 1, it is necessary to bring the base 2 of the tool and check the perpendicularity of the rod with an angle 3, fixed with screws on the prism 4, installed on the control plate 5.

When repairing the gage, you need to straighten, and then bring the sides of the rod (Fig. 150, 6) using the above devices. When finishing the lower working surface of the base 2, it is necessary to observe the perpendicularity of its rod 1. In this case, the sides of the rod are brought together with the lower surface of the frame 7. Before finishing the base, it is necessary to repair the frame and clamp 6, and in case of distortions, correct the leaf spring inserted into them. After repairing frame 7 and finishing the sides of the rod, the latter is installed in the frame, adjusting the zero position on the vernier scale, fixed with screws. Then the bar is turned over and re-installed in the frame, achieving the coincidence of the zero marks of the bar and vernier.

Micrometers, like other types of measuring instruments and devices, are tested and certified for their suitability for use. In micrometric measuring instruments, in most cases, micrometric screws fail, the working planes of which require careful finishing in this case.

As you will see from this article, modifying an electronic digital caliper is a very simple procedure, but it must be done carefully so as not to damage the instrument. The design of the electronic caliper provides 4 special contacts. These contacts, for example, can be used to connect an external power supply, control functions, etc.

The pin assignments are (from left to right): negative terminal, data, clock, and positive terminal.

To activate the hidden options of the electronic digital caliper, pins 2 and 4 must be connected together.

Perhaps different electronic calipers have some differences, but in general, their modification is carried out in the same way.

The first step in finalization is to find the screws holding the case together. On our caliper, they are located under a plastic sticker. Their location can be seen in the photo.

After opening the plastic case containing the circuit board, display and a few metal parts, you need to unscrew a few screws to remove printed circuit board.

Special care must be taken when handling printed circuit board and display.

The display is connected to the printed circuit board by means of a conductive rubber gasket. Be careful not to detach the display from the board, as this will make it difficult to align the connections during reassembly. And if the location is incorrect, the display may turn off spontaneously and strange characters appear on it.

After removing the printed circuit board of the electronic caliper, we get access to the necessary contacts.

Now you can solder 2 thin wires (the thinner the better). Solder one to pin number 2 and the other to pin number 4.

To close these terminals, it is best to use a micro button, for example, from an old computer mouse. The pins of the button need to be bent at a 90º angle (as in the picture) so that it fits snugly into the slot and therefore is held firmly in place.

After soldering the wires, the assembly of the electronic digital caliper is carried out in the reverse order. After assembly, soldered wires should stick out of the socket.

After that, solder the button and place it in the slot.

Because the button legs have been pre-bent, they spring the button and hold it firmly in place. Here's what it looks like.

By pressing a new button, we get access to some modes that were previously not available.

When the button is pressed for the first time, the electronic caliper enters the mode fast reading(FT), by pressing the "ZERO" button, we can freeze the measured value (H).

When the button is pressed again, the electronic caliper will enter the mode minimum value(MIN). In this mode, the display shows the smallest measured value.

If you press the "ZERO" button again, we will again switch to the mode of fixing the measured value (H).

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The caliper got its name due to the main element of its body - the rod, but the compass we are used to is a little far from this tool with its device. To understand a subject full of mysteries, we will try with the help of this article, consider its structure and principle of operation.

Caliper device - the main components and their purpose

The device of the caliper does not look complicated on the surface, but its parts are so compact and optimally composed that they make this device easy and convenient to use. And it can do a lot, and the measurements that are performed with its help are very important in many areas of industry and construction. When using a caliper, we get the linear dimensions of objects, both external and internal. And the accuracy, which in some models reaches an enviable level, makes this simple tool more and more in demand.

The purpose of the caliper is to measure the length, diameters, depth, but what provides this opportunity, we will analyze using the example of the simple form this fixture. The main node is the ruler, which is called the bar, giving part of the name to the tool. The divisions on it are usually equal to 1 mm, and total length usually 15 cm, but some models may be longer. ruler determines maximum size, which can measure this tool. This means that the maximum length or diameter of an object should be no more than 15 cm.

At the end of the ruler are sponges, or rather their halves, and the second halves are located on a movable frame that moves along the ruler, measuring the size of the object being examined. Sponges are internal and external, in the first incisors look outward, in the second - at each other. Consequently, the first ones are inserted into the object and move apart to fix the internal geometric parameter, and the second ones are moved apart widely, and then come closer to fix the object under study among themselves. To accurately measure or transfer it to another surface, the movable frame can be fixed with a special screw located on it.

On the main ruler, we can see the integer value of the desired size, but the vernier scale, which is printed on lower part borders to be exactly below the ruler's main markup. The vernier has ten divisions, each of which measures 1.9 mm, the entire scale is 1.9 cm long. These are the parameters of a conventional household caliper, on other models this ratio changes. Having found the vernier division, which coincides with any division of the main scale, you can refine the desired value to tenths of a millimeter. The use of a caliper is not limited to internal and external dimensions, you can also mark the depth of the holes, for this there is a tail that extends from the ruler. This is the depth gauge.

Caliper - classification and marking

The measuring tool caliper can be of 3 types and about 8 sizes, in any case, according to domestic regulatory documents. And it is important when buying any precision instrument, focus on the standards by which it is manufactured and calibrated. It is divided into types depending on the indicator of the measured value, from which we take the desired numbers. it can be vernier (ShTs), dial (ShTsK) and digital (ShTsTs) calipers. In the first case, we will have to go over both scales ourselves with our eyes, count the divisions and report the result. In the second case, we will see the numbers on a mechanical scale with a movable arrow, but in the third case, we will be shown the finished result on the display.

Within these species, subspecies can also be divided depending on the design and length of the main ruler. For example, you can divide tools by the type of material from which they are made. ShTsT-I can serve as an example of a hard alloy tool. There are differences in the device of sponges or accessories. So, ShTs-I and ShTs-III differ in the location of the jaws, in the first case it is two-sided, and in the second - one-sided. But in ShTs-II there is a micrometric feed frame, which will make marking easier if you need to transfer your measurements to another plane. It makes no sense to discuss the differences in standard sizes for a long time, one has only to say that the larger the ruler, the greater the error in the values ​​obtained.

How to measure with a caliper - instructions for beginners

Most technically developed people it is intuitively clear how to use a caliper, so we briefly recall the main points.

How to measure with a caliper - step by step diagram

Step 1: Fixing the Part

First, check the tool for serviceability, to do this, reduce the sponges without a part to zero, look at the clearance, how correctly they are connected, and also look at the scale to see if the zeros on the two scales coincide. After a positive result, you can start working with the part. It is most convenient to work when the tool is in your right hand, and the part to be measured is in your left, or it is completely fixed somewhere. If you are left-handed, then the ratio is, of course, the opposite. For measuring outer dimension open the jaws of the caliper, place an object between them and connect them. They should rest against the edges of the part being examined. If it is hard, you can lightly squeeze the lips for a firm touch. If the part is soft, do not do this, the results will be distorted.

Effort is controlled simply, if you try to move the lips relative to the object, then they should do it reluctantly, but if you also need effort for this, then you obviously squeezed it.

Move the frame more conveniently with your thumb right hand, while holding the barbell with the rest. Check the position of the caliper relative to the object, if there are any distortions (the sponges should be at the same distance from the edge of the object on both sides), it is better to raise the structure to eye level. To see more clearly, it is better to hold the object in the plane behind the instrument with the left hand, and not in front. Now you should carefully tighten the mounting screw, index and thumb, while the rest should continue to hold the bar. When the value is fixed, the part can be put aside and proceed to the study of the next step, how to measure the resulting number with a caliper.

Step 2: Remove value

It is best to read the readings also at eye level. First of all, we write down the value of the main scale, i.e. integer. To do this, we are looking for a stroke on the main rod, which is closest to the zero value of the vernier, this is an integer number of millimeters. You can remember, or you can mark it somewhere on a draft. Now we are looking for a stroke on the vernier that is closest to its zero, but also exactly coincides with some division on the bar. His serial number should be multiplied by the division value of the vernier used (usually 0.1 mm). If you are not sure that you know this value, look in the passport of this caliper.

Now the matter is small, you just need to sum up these numbers, and the result is ready. For example, on the bar you had a value of 35 mm, and on the vernier you counted 4 more divisions, then general meaning equals 35.4 mm (3.54 cm). After work, the tool is wiped (degreased), the sponges are slightly pushed apart (by a couple of mm), the clamp is loosened and placed in a case. If storage is planned for a long time, then you can lubricate it against corrosion.