What are the types of calipers

Types of calipers and their differences + photo

One of the most common and structurally simple measuring instruments, which is distinguished by its versatility, incredible accuracy of indications and the ability to measure the outer and inner diameters, is a vernier caliper.

Among its many varieties, which in addition have different sizes, you can find options with minimal errors. The tool itself is often used in everyday life, and in turning and mechanical engineering, one cannot do without it at all.

We invite you to learn about the types and differences between calipers, what they are and which one to choose.

General information

Principle of operation and purpose

The purpose of the caliper is to measure with high accuracy outside and inside the measured objects, and also the depths of the various holes.

A feature of the tool is its versatility. The common name for this tool is "barbell" among those who constantly use it, and is the simplest abbreviation of the word.

Such a tool "is able" to measure the inner and outer diameters of cylindrical and round objects, for example, nuts and bolts, is suitable for internal measurements of grooves according to the required parameters. The principle of measuring with a caliper will be to determine the size based on the position of the measuring frame, which moves freely along the bar with the scale that is applied. The value itself will be determined by the coincidence method, and the accuracy, depending on the accuracy class, will reach hundredths of a millimeter.

Device, properties and characteristics

If you connect your imagination, you will notice that externally a caliper looks like a symbiosis of a ruler and a hammer. The classic instrument consists of the following elements:

1. A bar with a marked scale, the maximum the size of the measurements will depend on the length of the rod.
2. Measuring frame - this is a moving part of the boom that can move along the boom. The vernier scale is applied to it, which makes it possible to determine millimeter fractions. A spring with a screw for fixing is installed inside the frame, which presses it against the rod, and this reduces the measurement error, which can increase due to the skew of the moving part relative to the stationary one.

   Instead of a vernier, a dial scale or a small digital display can be installed, and this will depend on the caliper model.

3. Fixed jaw - structurally represents a part of the rod or is rigidly attached to it, and is located on one side of the tool. The working area is the inner edge of the stationary sponge, and during measurements it must be tightly applied to the measurement object.
4. The movable jaw is a structural part of the frame or is rigidly fixed to it.The working part is also internal, and the part is located exactly opposite the fixed jaw so that when the frame is shifted, the edges of the two jaws touch.

   In this position, the zero parameters of the barbell and vernier scale must match.

5. The retractable bar is a part of the structural type of measuring frame, as well as its purpose for measuring depth in an object.

The design, which is discussed above, has one-sided jaws, which makes it possible to determine only the external dimensions of objects. For internal measurement, you need a caliper with jaws placed on both sides. The latter usually have smaller dimensions, which are located similarly, but on the opposite side of the bar, and the outer edges will be the workers.

Details

What to look for when choosing

Materials

What types of calipers are there by materials of manufacture? Metal calipers are usually made from stainless and carbon steel, as well as from low-alloyed tool steels KHVG and 9XC. Stainless tools are classics, but in the production of modern calipers, a composite is also used, for example, based on carbon fiber and polymer resin.

Dimensions

Typical dimensions of the classic caliper:

• Sponge size for external measurements from 3.5 to 30 cm.
• Sponge size for internal measurement from 0.

  6 to 2.2 cm.

• Measuring range up to 200 cm.
• Size vernier from 0. 9 to 3.

  9 cm.

• Weight (will depend on size and material) from 0.2 to 8. 9 kg.

Models with a measuring range of up to 5 meters can weigh more than 35 kg.

GOST

These current GOSTs regulate both the inspection and the production of tools (calipers):

• GOST 8. 113-85 - helps to determine the order of verification.
• GOST 166-89 - helps to define technical conditions.

Now a little about accuracy.

Accuracy

Vernier caliper is characterized by several accuracy classes:

• First class - the error in it will be 0.

  005 cm (twentieth of a millimeter).

• Second class - the error will be 0.01 cm (tenth of a millimeter).

For high-frequency measurements, a completely different instrument is used, which is called a micrometer. To clearly show what the accuracy class will affect, it is enough to assume that the diameter of certain drills should be determined without marking.

A caliper of the second accuracy class will make it possible to pick up drills with a diameter of 0.67 and 0.668 cm, and of the first class and 0.675 cm.For electronic type tools, the error can be 0.

001 cm.

Checking

In the process of performing work with a vernier caliper, a violation of the settings, various deformations of individual elements and the simplest wear can be seen.All this will affect the accuracy of the measurements, which can be distorted by adhering dirt, grease, metal filings, which cover the instrument with a magnetized layer.

Please note that every caliper owner needs to handle the tool with care and keep the tool clean.

The instrument should be checked every year to avoid various distortions of the measurement results.

To do this, it will be enough to contact a special service center for repair and adjustment. A special certificate is issued for the verification results of the verification. At home, you can perform a simple check of the correctness of the readings if you close the sponges of the barbell all the way. In this case, the zero strokes must match. Consider other types of calipers.

Marking

There are the following types of marking:

1. ШЦ-1 - gives the ability to determine the internal and external dimensions due to two pairs of jaws. The depth of the holes will be determined using the appropriate ruler.
2. ШЦ-IC - taking readings will be simplified due to the arrow head, and its gears will be meshed with the rack, which are installed in the rods.
3. ШЦТ-I - one-sided jaws have a hard-alloy coating. All are used in conditions with increased abrasiveness.

4. ShTsK - used where high measurement accuracy is not needed, because the readings are taken from a dial, and the spring mechanism is at the heart.
5. ШЦ-II - a frame feed mechanism has been added to the double-sided jaws, and this allows marking.
6. ШЦ-III - one-sided jaws and large sizes are a characteristic feature. He cannot measure depth.
7. SCC - readings are taken thanks to a digital scale.

Next, let's take a closer look at the types of calipers.

Varieties of calipers and cost

Calipers can be divided into such main types.

Analog

The counting can be conducted by the vernier, and its other name is "vernier". Cost from 450 rubles.

Pointer

No calculations required, easier way to use, because the measurement results will be displayed on a dial with a circular scale.

The cost is from 1800 rubles.

Digital

With a small display, and digital measurements are shown on it. Has high accuracy. Another name would be electronic. Cost from 780 rubles for the simplest models.

Moreover, barbells can be with a depth gauge (type T-I or I) and without it (type II and III).

Precision Vernier Caliper is the generic name for models that have a higher level of accuracy. By the way, if a monoblock instrument (fixed lips are not attached to the bar, but are an integral part of it) are capable of giving the most accurate readings. There are tasks in which a standard tool simply cannot cope.

Special Calipers

There are some striking examples of special models.

Marking

With carbide residual jaws and a special circulating mechanism. In addition to taking measurements, it is possible to draw arcs with the jaws themselves on carbide material. A caliper for marking will be similar options without a circular type mechanism with jaws based on hard alloys. Cost from 2600 rubles.

SCCD (for brake discs)

The types of calipers and their purpose are different.

Designs with elongated one-sided external measuring jaws, which have teeth on the working surface to improve the measurement accuracy. There are options that allow you to determine the thickness of car brake discs and discs without having to dismantle the wheels. The simplest week costs about 1,000 rubles.

Track

It is suitable for measuring rail surfaces. The cost of the instrument is from 20,000 rubles.

By the way, the following measurement tools, which are described below, can be attributed to the analogs of the caliper.

Stangenometer

This tool is needed in order to measure the teeth of racks and gears with an accuracy of 0.002 cm.

Stangen depth gauge

Such a tool is needed to measure the depth, height of a blind hole, protrusions, grooves.

Gauge Gauge

This tool allows without special skills to perform height measurements and mark out parts vertically with an accuracy of 0.

005 cm.

How to choose a good tool

The main advantages of a caliper is the accuracy of measurements. For this reason, a high-quality tool must be made of durable material and must also have easily visible markings and tolerate heavy use. Popular with experienced craftsmen are stainless steel tools engraved with graduations due to their high resistance to durability and corrosion.

The main principles of selection will be the following:

1. Length - it will determine the measurement range.

   It should be selected depending on the tasks. For use in everyday life, a 12.5 cm tool will be enough, and for building a house, for example, you will need a barbell 5 meters long.

2. Measurement step - roughly speaking, the measurement result will be much more accurate for those models that have the smallest distance between adjacent scale divisions.
3. Price - you shouldn't buy an expensive model for infrequent domestic use, but a good caliper won't be cheap.

   Craftsmen, for whom this instrument is the main one for measurements, should look towards the proven German, Japanese and Swiss models. High-quality instruments, especially electronic ones, are very expensive, and it is enough to buy them once, because it will be for a lifetime.The frequency of use should be based on the price of the instrument.

Before purchasing a caliper, make sure that there is no play between the stationary and the moving part, and that the zero marks of both scales coincide with the jaws flattened.

What you need to know about calipers

A vernier caliper needs to be handled with care because other factors may even reduce its accuracy and

measure the measurement results:

• Damage to the work surface - even a small scratch or malfunction can be decisive.

• Jaws worn, or lack of strictly parallelism between jaws.
• Accumulated dirt or dust between the moving parts of the boom.
• Zero readings configured incorrectly.

Store the instrument in a case, which must be included in the kit.

Manufacturers

Calipers are created by such manufacturers as TOREX, ADA, CHIZ, CALIBRON, SNIS, KRIN, MATRIX, GRIFF and others.

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