How to measure with a caliper: instruction, features and recommendations

No construction or even minor repairs can be carried out without measuring instruments. Traditionally they are roulettes or rulers.

However, there are often situations where only they can not do. For example, when it is required to measure the internal diameter of a hole or a pipe, the external dimension, the depth of the hole, etc., especially if high accuracy is required. Or how to know the diameter of a drill if the marking on it has worn off from the time? Nothing else remains, except how to measure the diameter of the caliper.

The caliper is invented more than a hundred years ago and is still a popular measuring instrument. To determine how correctly to measure the caliper, you need to understand its device.

Scale of the caliper

The basis of this device is the bar-bar.

The main and auxiliary scales are marked on the caliper body. To obtain the exact size, the indications of both scales must be added.

The whole millimeters are counted from left to right, the zero mark of the vernier serves as the beginning.

If you want to find a fraction of a millimeter, you need to find that bar of the vernier that coincides with the prime scale stroke. Then multiply its serial number by the scale division price.

As a result, we get the sum of two parameters - the whole millimeters and fractions.

How correctly to measure with a caliper

Before starting the measurement, the device should be checked for possible damage. If the calipers are skewed or sponges are erased, then they should not be used, since the results will turn out to be distorted.

Before you measure with a caliper (0.05 - the cost of division, for example), the sponge should be pressed tightly against the surfaces being measured, avoiding distortions and not pressing too tightly. There should not be any gaps between the part and the sponges.

To measure the depth of the hole, the depth gauge rod should be installed perpendicular to it, at the edge of the hole, pushing it to the stop.

When measuring rounded parts, it is necessary to monitor the perpendicularity of the frame in relation to the workpiece.

After measurement, the fixing bolt is tightened and the instrument reading is taken off.

To measure the diameter of the hole, the sponges are placed inside the hole to be measured as far as possible. This is achieved by using a scale on the rod.

When working with a caliper, it is necessary to constantly monitor the coincidence of the zero mark on the vernier with the zero mark on the bar itself. If this can not be achieved, then the device is clearly not suitable for work.

When measuring the dimensions of soft parts on a caliper, it is useful to have a special trim screw. It allows you to bring the sponge to the part slowly, without clamping the surface.

Professional masters, speaking of the use of calipers, do not cease to repeat that its accuracy is no worse than the classical instruments used by rulers and roulettes. How to measure with a caliper, if the master is used to his line and trusts only her? Of course, we mean high-quality tools manufactured exclusively at the plant, which have been subjected to an accurate check for compliance with the standards of measuring instruments.

Roulettes, circuses and corners, sold in construction markets, are unlikely to allow high-quality measurements. They can be used for jobs that do not require great accuracy.

Caliper device

With the caliper, you can measure the size from 0 to 15 cm. The accuracy of measuring the depth of the holes is 0.05 mm.

Notation:

1. Measuring sponges for external dimensions - in addition to simple measurements, with the help of these sponges it is possible to lay a number of parallel lines.
2. Measuring sponges for internal dimensions - with a divorce outwards.
3. Sponges for marking.
4. The frame is a fairly complex construction, which consists of several parts. In order to reduce the play, a spring is located inside it. The adjusting screw achieves smooth running. In addition, on the frame is a scale - auxiliary or vernier. The fission rate for most calipers is 1.9 mm. But this scale is not intended for direct measurements.
5. Rod scale - marking with a step of 1 millimeter. Ruler bar is the body of the device itself. Usually the length is 150 millimeters. It is made of alloy steel, it must be resistant to corrosion.
6. The depth gauge line is a retractable rod.
7. Nonius is a scale for measuring fractions of millimeters.

Types of sponges

Most calipers have scissors sponges. The question arises as to how to measure the internal caliper by a caliper. The required size is determined directly on the scale, without additional calculations.

There are also stepped lips. How to measure a caliper with these features? In this case, if holes and grooves are measured, then their size should be added to the dimensions obtained.

Design features of calipers

Special attention should be paid to instruments with a circular measuring scale. For example, how to measure the diameter of reinforcement with a caliper with an ordinary scale, if the operator has poor vision? With the help of a device with a circular scale, you do not have to scrupulously deal with the combination of scales and calculate the fractions of millimeters.

On the dial, the measurement results are immediately visible. This is especially useful when you need to find an answer to the question of how to measure the diameter of a caliper.

Different models may have a different value for the vernier count. Other design changes are possible. In any case, to obtain the correct values, the device must be kept clean and in good order. In addition, you must constantly monitor the condition of the lubricant and do not forget to update it in time.

All measurements are carried out, of course, mechanically. And it is desirable to use in work calipers made at the profile of the manufacturer.

General recommendations when using the device

1. It is possible to measure the dimensions of round billets.
2. Internal measurements using calipers are much more accurate than those of all other measuring instruments.
3. The depth of the hole or groove is very simple to measure with the depth gauge available in the caliper. It is pulled out of the housing and measured.
4. It is also easy to measure the ledges with high precision with the help of a combination of jaws.

Narrow profile calipers

In addition to universal calipers, there are many special, narrow profile devices.

For example, a fine caliper can be added to a simple caliper. This significantly improves the accuracy of the measurements. The presence of a tuning screw indicates a higher class of the device.

There are calipers with a longer depth gauge and different shapes of sponges.

In most cases, it is sufficient to have a universal caliper to conduct domestic work and use in private workshops.