Vernier calipers: purpose, types, characteristics + choice

Calipers

Calipers

This is a measuring tool that allows you to determine external and internal dimensions, as well as the depth of holes and ledges. It consists of a rod with a measuring scale and a movable frame with a vernier scale. Using a vernier can significantly improve measurement accuracy.

Due to their ease of use, calipers are the main measuring tool in production. They are most often used when carrying out turning, milling and metalworking work. The caliper is included in the kits for visual and measuring control of the VIC.

Technical conditions for calipers are regulated by GOST 166-89. The verification procedure is contained in GOST 8.113-85. A sample caliper verification protocol can be downloaded from the link. If necessary, a caliper can be issued

own metrological service. Detailed information about caliper verification is here.

Types of calipers:

• ШЦ-I. It has jaws for measuring external dimensions and jaws for measuring internal dimensions of parts. There is also a ruler for determining the depth of holes and ledges;
• ShTs-IC. The size is measured using a special arrow head mounted on a movable frame. This makes taking readings much easier;
• SCT-I. Designed for use in highly abrasive conditions. It has a one-sided arrangement of jaws coated with hard alloy;
• SHTs-II. It has a double-sided arrangement of jaws. Unlike ShTs-1, it allows marking, for which it is equipped with a frame feeding device;
• ШЦ-III. Differs in large sizes. With one-sided arrangement of jaws, without the ability to measure depth;
• SCC. Equipped with a digital scale.

Video on how to use a caliper.

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How to properly store a tool

To extend the life of your caliper, it must be stored properly. To do this, you should use a special case. It is recommended to periodically wipe the surface of the device with a soft cloth to remove dirt. If used frequently, it does not require additional protective measures. If you use it rarely, then you need to treat it with machine oil. It is necessary to avoid exposure to moisture and sunlight and mechanical damage - impacts, scratches, etc.

Storing the caliper

A caliper is a tool that is often required by both professional craftsmen and amateurs. If you need to take measurements frequently, you will need to purchase such a device. When choosing the right model, the user should be guided by the specifics of the work, taking into account the design features and cost of such tools.

Vernier caliper type ШЦ-I

Caliper type ШЦ-1 with double-sided jaws and a special ruler, used for measuring internal and external surfaces as well as the depth of holes with a vernier reading of 0.02 mm. The ShTs-1 vernier caliper meets the requirements of GOST 166-89 and is included in the State Register of Measuring Instruments under No. 41093-09. mm. The methodology for checking calipers is regulated by GOST 8.113-85.

The measurement error on the main scale for calipers of the 1st accuracy class is 0.05 mm, for the 2nd class it is 0.1 mm. Measuring range from 0 to 300mm depending on the model. If necessary, a verification certificate can be issued.

The main technical characteristics are given in the table:

CONTROL AND TEST METHODS

4.1. Verification of calipers - according to GOST 8.113 and MI 1384.

4.2. When determining the influence of transport shaking, an impact stand is used, which creates shaking with an acceleration of 30 m/s at a frequency of 80-120 beats per minute.

The calipers in the package are attached to the stand and tested with a total number of impacts of 15,000. After testing, the error of the calipers should not exceed the values ​​​​specified in Table 3.

It is allowed to test calipers by transporting them on a truck at a speed of 20-40 km/h over a distance of at least 100 km along a dirt road.

4.3. The impact of environmental climatic factors during transportation is determined in climatic chambers in the following modes: at a temperature of minus (50±3) °C, plus (50±3) °C and at humidity (95±3)%. Exposure in the climatic chamber for each of the three types of tests is 2 hours. After the tests, the error of the calipers should not exceed the values ​​​​indicated in Table 3.

It is allowed, after holding the calipers in each mode, to keep it under normal conditions for 2 hours.

Vernier caliper type ШЦ-II

Calipers of type ShTs-2, just like ShTs-1, have jaws for measuring the external and internal dimensions of parts, as well as a ruler for determining depth. A special feature of ShTs-II is the ability to mark parts using a precision frame feed device.

General requirements for ShTs-2 calipers are contained in GOST 166-89. ShTs2 is included in the State Register of Measuring Instruments under No. 41094-09, the measurement range varies from 0 to 500 mm depending on the model. If necessary, a verification certificate can be issued for the instrument.

The main technical characteristics of ShTs-II are given in the table:

ACCEPTANCE

3.1. To check the compliance of calipers with the requirements of this standard, state tests, acceptance inspection, and periodic tests should be carried out.

(Changed edition, Amendment No. 2).

3.2. State tests - according to GOST 8.383* and GOST 8.001*. ________________ * PR 50.2.009-94** applies on the territory of the Russian Federation. ** The document is not valid on the territory of the Russian Federation. The procedure for testing standard samples or measuring instruments for the purpose of type approval, the Procedure for approving the type of standard samples or the type of measuring instruments, the Procedure for issuing certificates of approval of the type of standard samples or the type of measuring instruments, establishing and changing the validity period of these certificates and the interval between verifications of measuring instruments are in effect. , Requirements for approval marks of the type of standard samples or the type of measuring instruments and the procedure for their application, approved by Order of the Ministry of Industry and Trade of Russia dated November 30, 2009 N 1081. - .

Checking the errors of calipers at a temperature of (20±10) °C is carried out only during state tests.

3.3. During acceptance inspection, each caliper is checked for compliance with the requirements of clause 1.3; 1.4; 1.6; 1.8; 2.3-2.10; 2.12.4; 2.16; 2.18; 2.25; 2.26.

3.4. Periodic tests are carried out at least once every 3 years on at least 3 calipers of each standard size from those that have passed acceptance control for compliance with all the requirements of this standard.

Test results are considered satisfactory if all samples meet all tested requirements.

(Changed edition, Amendment No. 2).

3.5. (Deleted, Amendment No. 2).

Vernier caliper type ШЦ-III

ШЦ-3 is a one-sided caliper with the ability to mark parts and determine internal and external dimensions. The ShTs-3 vernier caliper meets the requirements of GOST 166-89 and is included in the State Register of Measuring Instruments under No. 41094-09. Measuring range from 0 to 2000 mm depending on the model. A certificate of verification can be issued upon request.

The main technical characteristics of ShTs-3 are given in the table:

Electronic calipers type ШЦЦ-I

Electronic calipers are used to determine external and internal dimensions, as well as the depth of holes and ledges. This type of caliper has a digital readout scale that allows you to quickly take readings, reducing the chance of subjective error. The scale is based on a liquid crystal indicator.

In addition to traditional use in production, electronic calipers are often used in metrology services and quality control departments. ШЦЦ-1 meets the requirements of GOST 166-89 and is included in the State Register of Measuring Instruments under No. 41093-09. The tool measurement range is from 0 to 300mm depending on the model. If necessary, a verification certificate can be issued.

The main characteristics of electronic booms are shown in the table: