How to use a caliper: step by step instructions. How to use a vernier caliper - a step-by-step guide to using modern internal distance measurement tools

The main task of a caliper is to measure dimensions. The device, although simple, nevertheless allows with high precision try on almost any item. It finds application everywhere - from workshops of all directions to beauty salons (it is used, for example, to create the ideal shape of eyebrows).

Device

If you look at the photo of the caliper, it becomes obvious that the main elements of the device are typical for any of its types:

Ruler - bar
Jaws for measuring the outside and inside of the part
Depth gauge - an additional option allows you to measure the depth of holes and grooves
Vernier is an additional movable scale that allows you to measure with an accuracy of tenths of a millimeter (up to 0.05 mm, greater accuracy no longer makes sense, since the human eye cannot understand the measurement result)
Measurement fixing screw

The length of the rod of the device is 15 cm, but there are also specific models with a longer ruler.

The tips on the jaws are made of very hard metal, which makes them also suitable for marking (you can just draw lines on the surface of plates, parts, etc.).

Measurement scheme

Let's take a closer look at how to use a caliper. First you need to decide on the nature of the measurements, and depending on whether the inner, outer part or the depth of the product will be measured, it is used required element device, the measurement principle is the same in all cases, therefore, consider using the example of measuring the outer part of the part:

The sponges are spread apart, the object is placed between them and the sponges are connected (if the object is hard, then you can squeeze the sponges well, but if a soft object is measured, then the main thing is not to crush the part, otherwise the measurement result will be incorrect). To make it convenient to take a measurement, the result can be fixed with a fixing screw.

The values obtained are checked on the ruler.

Since the number may not be an integer, it is necessary to pay attention to the vernier to determine the proportions. First of all, you need to find the division that coincides with the division of the main ruler (for example, the main ruler gave a result of 2 cm and 4 millimeters "with kopecks", to calculate the "kopecks" we see that the risk 7 on the vernier coincided with the risk on the main ruler, which means it turns out result 2.47 cm).

Important! Only 1 risk should match. If several marks coincide (do not mean zeros), then this device should not be used, since it is not working properly.

Varieties of calipers

All types of calipers are given in GOST 166-89. The most common are vernier, dial and digital.

Vernier caliper

The device is in the form in which we are used to seeing it, and it was precisely its device that was described above.

Dial caliper

An alternative to the vernier and the ruler is the dial, the arrow immediately shows the measurement result. It is much easier to use, since you do not need to make calculations according to the vernier. The Achilles' heel in the dial calipers is glass; if it breaks, the device is no longer suitable. But now the SCC with a more durable carbon-fiber display has appeared on the shelves.

Digital vernier caliper

On the bar with graduations there is a carriage with an LCD display, where the measured data obtained with a caliper is automatically displayed. At the touch of a button, they can be converted from millimeters to inches and vice versa, and there is also an additional button for saving measurement results and zeroing them.

An electronic caliper is good in accuracy, clarity and speed of measurement, the movement of the jaws is more smoothly adjusted in it. And, you must admit, it is more convenient to look at the numbers than to try, straining your eyes, to catch the divisions.

Care and storage

The caliper belongs to the category of high-precision instruments. Therefore, it requires careful maintenance. The presence of dirt or paint on it is unacceptable, as this will critically spoil the measurement readings.

A high-quality caliper is the key to a good production result.

Photo of using a caliper

It just so happened (at least for the author) that the accuracy of measurements is made: with a ruler up to centimeters and a half, a caliper up to millimeters, but tenths and hundredths of a millimeter are "caught" exclusively with a micrometer. What prevents to use a vernier caliper to measure tenths of a millimeter, because it is for this, and is intended, "offhand" will be difficult to answer. Often, even those who know the device of this measuring tool will be careful to indicate the size fixed with a caliper with an accuracy of ten - for the scale (vernier) is small in nature, "responsible" for determining tenths of a millimeter. I admit that it is for this reason that some of the calipers began to be produced equipped with a dial scale and even equipped with an electronic display (electronic).

And what prevents you from upgrading an existing caliper and thereby bringing the accuracy of its measurements closer to that of a dial gauge and, for example, equipping it with a magnifying glass? He sat down to the computer and began to draw the device that had already visited the imagination.

Refinement scheme

The sketch was made in a section, where the number:

1 - the caliper bar is marked
2 - movable caliper frame
3 - holder frame, it is installed on a movable frame
4 - screw securing the frame to the frame
5 - the screw securing the frame with the magnifying glass to the frame
6 - magnifying glass frame
7 - the spring pressing the frame to the head of the fastening screw
8 - magnifying glass

In accordance with the finished sketch, I collected the most suitable components of the future holder "by bottom".

In a textolite cube (in the past, some part of the case electronic device, and in the future the holder frame) increased the existing groove with a file to the size corresponding to the movable frame of the caliper and drilled in the center a hole with a diameter of 3 mm for the fastening screw.

On the side is done threaded hole M4 for the screw for attaching the frame with a magnifying glass. With the end of the production of the bed, time-consuming operations requiring precision and careful adjustment are completed.

A frame was made from a piece of soft plastic (in addition to the existing one). Two holes have been drilled in the plastic plate. The smaller one is for the mounting screw of the frame, the larger is for the already existing frame (into which it is screwed along the thread, which makes it possible to adjust the sharpness).

The device is assembled according to the drawing. I did not specially cut the thread in the additional frame, it was made by the thread of the old (metal) frame when screwing in for the first time. For this, a soft plastic plate was selected, and the hole was made 0.5 mm less than necessary. It is clearly seen that the risks of vernier (the name of the scale for determining tenths of a mm) are increased to the size of a more comfortable observation. This makes it possible to confidently determine the measured size with an accuracy of "ten". And even more - now you can easily distinguish a wire with a size of 0.85 mm from 0.80 mm by means of measurement.

Caliper reading procedure

count the number of whole millimeters, for this they find on the bar scale the stroke closest to the left to the zero stroke of the vernier;
count fractions of a millimeter, for this, on the vernier scale, find the stroke closest to the zero division and coinciding with the stroke of the barbell scale - its serial number will mean the number of tenths of a millimeter;
add the number of whole millimeters and fractions.

The fixture is easy to install and remove and can only be used when needed. Project author - Babay iz barnaula.

Discuss the article UPGRADE ROD

As you will see in 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 includes 4 special contact... These contacts, for example, can be used to connect an external power supply, monitor functions, etc.

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

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

There may be some differences between different electronic calipers, but in general they are modified in the same way.

The first step in reworking is finding the screws holding the case together. On our caliper, they are located under a plastic sticker. Their location can be seen in the photograph.

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

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

The display is connected to the printed circuit board via a conductive rubber gasket. Be careful not to disconnect the display from the board as this will make it difficult to align the connections during assembly. And if the location is incorrect, the display may turn off spontaneously and strange characters may 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 the old computer mouse... The pins of the button must be bent at an angle of 90 º (as in the picture) so that it fits snugly into the slot and, therefore, is firmly held in place.

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

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

Since the legs of the button have been pre-bent, they spring the button and it is held firmly in place. This is 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 vernier caliper enters the fast reading mode (FT), when the “ZERO” button is pressed, we can freeze the measured value (H).

When the button is pressed again, the electronic vernier caliper enters the MIN mode. 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).

Votes)

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Helping the toolmaker

Vernier tools inspection and repair

Vernier tool malfunctions and checks.

Most typical malfunctions vernier tools, as a result of which the accuracy of readings is impaired, are: wear measuring surfaces and bluntness 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 vernier; loosening of the spring; wear of the thread of the screw and nut of micrometric feed and a number of others. p The readings of vernier tools with a readout value and 0.05 mm are checked using end measures of length of the 2nd accuracy class (6th grade), and with a readout value of 0.1 mm - by means of end measures of length of the 3rd class.

The misalignment of the movable jaw is relatively motionless, and is also detected using a gauge block.

Having established a limit measure in two extreme positions, readings are taken and, by their difference, the value of the non-parallelism of the measuring surfaces caused by the skew of the movable jaw is judged.

The wear of the measuring surfaces is determined by the value of the discrepancy between the zero lines of the scales of the rod and the vernier with tightly shifted jaws. For vernier tools with a reading value of 0.02 and 0.05 mm, the gap between the measuring surfaces should not exceed 0.003 mm, and for vernier tools with a reading value of 0.1 mm - 0.006 mm. In fig. 79.6 shows how with the help of gage blocks and a curvature 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, f. A limit measure is placed between the jaws for external measurements, and then, using another vernier tool, the distance between the jaws for internal measurements is checked. This distance must be equal to the size of the gauge block.

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

Repair of caliper tools. The wear of the working surfaces of the vernier tools is eliminated by straightening the jaws with their subsequent finishing. Defects of the measuring surfaces of the jaws are also eliminated by straightening and the coincidence of the zero lines of the scales is achieved. After straightening, they begin to fine-tune the measuring surfaces of the posts 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, by moving the pri-r between the jaws with little effort, the surfaces are fine-tuned from the side of both sharp and blunt jaws until flatness, parallelism and the same size of the solution of both sides are achieved.

Rice. 2. Finishing 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 to the jaws of the rod and the dimensions between them are controlled by end measures, while the force with which the measure is introduced between the jaws should be the same for both sides. By inserting a gage block 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 held up by the ends of the jaws, freely rotating further along the entire surface, or has a gap in front, then the jaws are not parallel.

The outer surfaces of the blunt jaws are brought to parallelism. The size of the jaws must be an integer number of millimeters with tenths (for example, 9.8 mm). After finishing the jaws, the vernier is set to zero bar division. 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 coincide with the first and corresponding divisions of the bar. In this position, the vernier is fixed.

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

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

Repair of lightweight calipers in case of jaw breakage is carried out in next order... After the vacation in the salt bath, the worn or broken end of the sponge is cut off. Then, in the thickened part of the leg, a slot is cut with a disk cutter, the width of which is equal 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. The sponges are filed to the specified size and hardened. After cleaning, their measuring surfaces are fine-tuned.

Rice. 3. Repair of the caliper.

If both jaws break, the entire upper leg is replaced with a new one. To do this, rivets are knocked out and the broken leg is removed from the bar. In the workpiece of the new leg, a rectangular window is milled and sawed, in shape and size equal to the end of the rod. Then a leg is put on the bar, the perpendicularity of its position relative to the edges of the bar is verified, holes are drilled elsewhere and the leg is riveted. The sponges are sawed off so that their configuration and dimensions correspond to the shape of the frame jaws, and then they are adjusted.

The broken sponges of the frame are replaced with new ones, for which, after knocking out the rivets and removing the unusable sponge, a blank of a new sponge is riveted in its place, filing it, hardening and finishing.

Repairing broken jaws of calipers with a stamped bar is somewhat more difficult, since the entire bar, together with the jaws, has the same thickness and it is impossible to insert a new jaw. Riveting overlays does not always provide sufficient bond strength. Welding can be used, but it is best to replace the entire top of the boom with a new stem.

For this purpose, after annealing and cutting off the jaws, the end of the ruler is milled or sawed off 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 leg, it is necessary to ensure that the zero division of the vernier of the frame roughly coincides with the zero division of the scale on the ruler, since with a significant displacement of the vernier, too much metal will have to be removed at its end, which will worsen the quality of the repair.

Deformation of the bar can be caused by curvature or uneven wear of the bar. work surface... The curvature of the rod is eliminated by straightening by bending in a vice with three narrow brass spacers.

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

To eliminate the misalignment of the vernier with the ruler scale, 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 sawn, after which, by rearranging the vernier, they fix it in the correct position.

Repair of other universal measuring instruments (goniometers, height-gauges and vertical-gauge-binometers) is similar to the repair of calipers.

The main defects of the depth gauge can be the non-straightness of the reference 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 reference plane of the body and the end of the ruler, they are brought together on the 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 a vernier is done in the same way as a vernier caliper. When setting the ruler to specific size its end is aligned with the plane of the depth gauge. In this position, the zero division of the vernier is aligned with the zero division of the ruler scale or with the division corresponding to the height of the set of gauge blocks, after which the vernier is fastened with screws.

Good time of the day! Today we will talk about how to correctly take measurements using a universal measuring tool- vernier caliper. It can be used to determine the outer / inner dimensions of the parts, as well as the depth of the holes.

The photo shows two instruments with a vernier scale division of 0.1 and 0.02 mm.

Due to its special design, the tool allows you to fix the part, thus reducing the likelihood of an error at the time of measurement.

Caliper device:

Barbell;
Moving frame;
Main scale;
Jaws for measuring internal dimensions;
Sponges for measuring external dimensions;
Depth gauge;
Vernier;
Locking (locking) screw.

When using a caliper, you should adhere to the following rules:

The jaws must not be skewed.
After the measurements have been made, we fix the moving frame with a locking screw.
While reading the readings, we hold the caliper directly in front of our eyes.
It is necessary to store the instrument in a special case, in a clean state.
After use, wipe the tool with a clean, soft cloth.

Measurement Principles

Before starting measurements, we check the instrument for accuracy. To do this, we bring together the jaws of the caliper. Zero marks, the tenth line on the vernier scale and the nineteenth line on the main scale must match.

Measurement of external dimensions. We spread the jaws of the caliper slightly larger than the dimensions of the part to be measured, and then bring them all the way down, clamping the part.

Measurement of internal dimensions. We expose the tool to the zero position, then place the jaws in the required plane. Then we breed them all the way.

Depth measurement. We rest the tool end on the part and begin to move the moving frame until the depth gauge stops or reaches the desired point.

Performing markup. We set the given value, fix the tool with a locking screw, rest one of the jaws against the edge of the part and apply markings on the surface of the workpiece (straight lines, notches, circles). But it is better to make markings with tools specially designed for this purpose and spare an accurate, expensive measuring tool.

Reading the readings of the caliper

We count whole fractions of millimeters on the main scale to the zero mark of the vernier, and tenths (hundredths) of a millimeter - on the vernier scale, starting from the zero mark to the first mark that coincides with the main scale.

A few examples:

How to store the instrument correctly

It is best to store your instrument in the case in which it is sold. Do not allow dust, sawdust to enter. Avoid contact with moisture and avoid accumulation of condensation. Avoid impacts and scratches that can deform the instrument and reduce the measurement accuracy. Wipe the surface with a dry cloth after each use. You need to store the tool with diluted jaws (2-3 mm). Careful handling allows it to be used for many years and even decades.

In addition to the tools presented in this article, there are several more varieties of calipers:

Vernier caliper with dial. In the recess that is located on the rod, there is a rack with a gear attached to it. Readings are read from the bar and dial.

Vernier caliper with digital display.

I hope the information provided was useful! Thank you for your attention!