Vernier calipers / calipers - structure and correct reading

• The structure
• Different types of calipers
• The parts of a conventional vernier caliper in detail
• The advantages and disadvantages of a caliper
• The correct operation of calipers

A vernier caliper, also called vernier caliper or vernier caliper, is a length measuring device for internal and external dimensions. It consists of a pole with 4 measuring legs, 2 of which are movable. The reading scale is a centimeter scale or millimeter scale and the so-called vernier scale.

The caliber is a very useful measuring instrument, which is needed for the production and for manual work. Since the slider is a measuring instrument and not a teaching, so one renounces now almost entirely on the terms caliper or caliper, which were commonplace in earlier times, especially in southern Germany. Also the term caliber could not prevail in German language use successfully.

The structure

The caliper consists of 2 sliding parts, which also explains where he got his name from. At the top he has a locking screw, which can fix the slider, so that a set measure is maintained. On the pole is a scale with a normal graduation in centimeters, corresponding to the conventional rulers. Other models also have a scale in inches, which is above the centimeter scale. The scale on the lower (moving) side is called the vernier. For models with the additional inch scale, the corresponding vernier also stands on the upper, movable side. It is used to measure very small lengths that are difficult for the human eye to grasp, for example, a more accurate millimeter pitch on a centimeter scale.

The vernier scale has existed since 1631 and was made famous by the French mathematician Pierre Vernier. In addition, the slide has a depth measuring rod, with the help of which, for example, to determine the exact depth of holes. In general, the slider on the back has a table on which you can determine the hole size for drilling for tapping. For older models, however, these data are outdated and outdated. As a rule of thumb, however, the diameter of a hole to M8 is 0.8 times the thread diameter.

In the present time, the sliders usually have a digital display. This does not make the measurement more accurate, but it makes reading easier.

Different types of calipers

Since these measuring instruments have many advantages, they are available in several different types, depending on the field of application and possibility. Here are some listed:

• Precision Calipers
• Depth gauge
• Height caliper
• Precision workshop calipers with linear scale
• Digital workshop caliper with an LCD display and a fine adjustment device
• Precision caliper with a round scale
• Precision gear meter
• Digital precision caliper with the capacitive measuring system

The parts of a conventional vernier caliper in detail

• the fixed measuring leg with a jaw
• the movable measuring leg with a jaw
• the rail with the main scale
• the slider
• the vernier scale
• the locking screw
• the depth measuring rod

The advantages and disadvantages of a caliper

Compared to other measuring devices, the slider has a robust design. He also tolerates a fall once. You can not break it so fast. It is cheap and easy to use. Because it is so small and handy, you can carry it comfortably in your pocket. Thus, it is well suited for traveling and always and everywhere mobile to use. Its disadvantage is the possible measurement uncertainty, which can be greater than with other digital devices. Each caliper is only as good as the human being who operates and reads it.

The correct operation of calipers

Step 1: Open the slider and clamp the workpiece to be measured between the two lower jaws. The same procedure is used to determine an inner diameter, however, using the upper measuring jaws and inserting them into the opening.

Step 2: Press the movable jaw firmly against the workpiece

Step 3: Fix the movable jaw by tightening the screw

Step 4: Read off the measurement (always at the zero mark) on the centimeter scale

If the zero stroke does not exactly hit a millimeter line, then you can perform a more accurate measurement through the vernier scale. For example, if the approximate measurement is 24 decimal, you can see which line of the (lower) vernier scale exactly matches a millimeter line of the upper centimeter scale. If, for example, the 9 of the vernier scale coincides with a line on the upper scale, the value to be determined is 24.9 mm .

Tips for quick readers

• Clamp the workpiece
• fix movable slide
• Read centimeter by scale
• Match scale centimeters and vernier search
• read exact value