In daily life, many measuring tools are used, whether to measure length, width, diameter, etc. One of them is a caliper, which is an instrument used to measure relatively small objects.
Judging by its shape, this measuring tool is not much different from a ruler, except there is a part that is used for stabilization. The way a caliper works is to hold the object to be measured.
This tool, also called a slide rule or vernier caliper in English, is often used by technicians and construction workers. Apart from that, the sliding ruler is an important measuring tool in physics.
What is the meaning of caliper?
Calipers or slide rulers are usually owned by construction workers and technicians to measure various things, such as depth of pipes, diameters of pipes, thickness of objects and so on.
Although it is a measuring tool, this caliper is only specifically used to measure relatively small-sized objects. Why? Because this term is limited in size and the way to use it is by disking or installing it
The objects that are measured using a slide ruler are usually types of objects that cannot be measured using a regular ruler. Apart from that, compared to a regular ruler, a compass has higher accuracy in measuring an object.
What are the smallest and largest scales on a caliper? The scale starts at 0.1 millimeter (mm) or 0.01 centimeter (cm). Meanwhile, for a regular ruler, the smallest scale is 1mm or 0.1cm. This is why a slide rule is more accurate for measuring small objects.
Parts of a vernier caliper
People will certainly find it difficult to use a caliper if they do not know the parts in a measuring tool. The caliper base or slide consists of several parts as follows.
1. Internal jaw
The internal jaw on the caliper is divided into two other parts, namely the fixed jaw and the sliding jaw. The function of the jaws in the caliper is to measure the depth of the hole or gap in the object.
For example measuring the thickness of paper, table, iron plate and so on.
2. External jaw
Apart from the inner jaw, there is another part of the caliper called the outer jaw. What is the function of the external jaw? As the name suggests, this section is used to measure the external part of the body, for example diameter, length or width.
Not much different from the internal jaw, the external jaw of the caliper also consists of two parts, namely the fixed jaw and the sliding jaw. Things that can be measured with the external jaw include the diameter of pipes, rings, and the like.
3. Stem depth gauge
At the lower end of the sliding ruler there is a small rod called the depth measuring rod. Its function is to measure the depth of a hole in a particular object.
4. Main scope
Like other measuring instruments, calipers are also equipped with numbers that indicate the scale of measurement. At first glance, these numbers are almost the same as the numbers on a regular ruler.
The numbers or major scale are written on the capillaries in units of centimeters or inches, and their length usually ranges from 15 cm to 17 cm. The main function of this scale is to determine the final results of measuring things.
The main scale always uses units of cm or inches, unlike the nonius scale which is expressed in millimeters and inches.
5. Scala Nonius
If you pay attention, there are two line-shaped scales on the ruler, as well as the slide ruler. The larger number is called the major scale, while the smaller number is called the nonius scale.
The Nonius caliper scale unit uses millimeters (mm) or inches (in) and increases the accuracy of measurement results. For example, the diameter of the tube is 4.45 cm, which is of course more accurate than simply writing 4.5.
6. Locking bolt
The method of using a vernier caliper is to clamp or hold an object with a clamp on the measuring instrument. For the measurement results to be accurate, the object must not move. Well, this locking bolt will hold the object so that it doesn’t move when you measure it.
The locking bolt will hold the caliper jaw so that the object being clamped and measured does not move. If the object does not move or change, the measurement results obtained will be more accurate.
What are the types of vernier calipers?
This measuring tool, often referred to as a caliper, has a variety of functions. In order to meet the need for highly accurate measurement results, there are several types of calipers that can be used, namely:
1. Manual or analog calipers
Most of what builders own and use are manual or analog types of calipers. This type of terminology is also commonly used in practical training at school by students. As the name suggests, this type of caliper is still used by hand.
Since it is still manual, you have to be very careful when using it. Apart from that, in order to know the measurement results, they must first be calculated manually.
2. Digital caliper
Digital calipers are a form of development from the manual or analog types. This type of scope uses a display that can display a display with digital numbers. The advantage of this type of caliper is that the measurement results are displayed without calculating them manually.
The advantage of using a digital slide rule is that results are more accurate and faster when used to measure large quantities of objects. But of course, the price of digital calipers is more expensive than the analog or manual type.
3. Clock or watch caliper
Another type is a compass or slide rule that can be read like a clock or watch. This type of caliper has a needle like the one on an analog watch. Attached to the front is a stopper and measuring watch that replaces the non-ius gauge function.
4. Caliper height
This type of caliper is used to measure the height of an object. Its distinctive feature is a measuring jaw that can move quickly vertically against a measuring rod perpendicular to the base.
The measuring jaws on this height caliper are placed parallel to the base, so that the line is perpendicular to the base where the object is placed. For this reason, when using a height caliper, the reference surface must be flat, such as a table for example.
How to use vernier caliper?
In fact, it is not difficult to use a slide ruler or slide ruler. In order for the results of the measurements taken to be correct, make sure to use the caliper correctly. This method is as follows.
- Take the object or object you want to measure, for example a tube, ball, etc.
- Then take the caliper, open it from the jaw and move it to the left side until it is completely tightened so that the measurement results are accurate.
- Look again to see if both parts of the measuring jaw are closed and pointing to 0 (zero) or not. This section is important so that there are no errors in measurement, or what is called zero error.
- Next, loosen the locking screw and pull the sliding jaw to the right side. Do this until the object to be measured is between the jaws.
- If so, place the object you want to measure between your jaws and double check that the position is correct and matches what is being measured.
- Next, pull the sliding jaw to the left side so that it can lock in the object or object being measured, and don’t forget to turn the locking screw until it “clicks”.
- If so, now pay close attention to the line between the top and bottom of the scale or vernier. Find out which number correctly connects the line on the vernier scale.
- Finally, calculate by adding the two numbers obtained. This is the measurement result from the measuring rule or slide rule, also known as a caliper.
Advantages of long reach or sliding base
This measuring tool is often used in construction projects, technicians, and physics lessons at school. Why are veneer calipers so widely used, because they have many advantages over other measuring instruments.
The advantages involved are:
- The precision and accuracy are high, the scale starts from 0.05mm to 0.01mm
- It can be used to measure the outer diameter of an object by applying pressure on it
- It can be used to measure the inner diameter of an object by stretching it
- It can be used to accurately measure the depth of an object.
- The price is relatively cheaper when compared to similar measuring instruments with the same accuracy results.
Examples of questions and discussion
After learning about the meaning, parts, types and how to use slide rule, for better understanding, you should get practice questions. Below is an example of a question and discussion.
1. Example question 1
What are the measurement results from the sliding ruler as in the image below if you use mm?
Discussing questions:
- The main scale in the picture shows the number 11 mm or 1.1 cm, indicated by a single line after the number 1 on the main scale.
- The vernier scale shows the number 0.65 perfectly straight with the line above it, the numbers 6 and 7.
So the measurement result from the above image is 11.65mm which is obtained by adding 11mm and 0.65mm.
2. Example question 2
Tenth grade middle school students measure the thickness of a copper plate using a sliding ruler. The results of the measurements taken are shown in the image below. How thick is the copper plate that middle school students measure?
Discussing questions:
- The main scale shows 9 mm or 0.9 cm
- The vernier scale shows 0.8 mm
So from the gauge data obtained, the thickness of copper is 9mm + 0.8mm = 9.8mm or 0.98cm.
A caliper is an instrument used to measure relatively small objects, such as paper thickness, pipe diameter, etc. Apart from being used in practical physics lessons in school laboratories, this tool, also called a slide rule, is also used by technicians.
There are several types of slide rules that can be used depending on what you want to measure, from analog to elevation. Measurement results on a slide ruler or vernier caliper are more accurate when compared to other measuring tools, such as a ruler, for example.