Vernier Caliper: Definition, Diagram, Least Count and More

What is Vernier Caliper?

A Vernier caliper is a precision measuring tool used to measure the internal and external dimensions of objects with high accuracy. It is commonly used in engineering, metalworking, and machining operations. The Vernier caliper consists of two main parts: the main scale and the Vernier scale.

The main scale is a graduated ruler with markings in millimeters or inches, and it is used to measure the length of an object. The Vernier scale is a secondary scale that is used in conjunction with the main scale to achieve a higher degree of accuracy. It has a series of equally spaced markings that are slightly smaller than the main scale markings.

To take a measurement with a Vernier caliper, the object is placed between the two jaws of the caliper, and the jaws are adjusted to fit the object snugly. The main scale reading is taken at the position of the zero mark on the Vernier scale. The position of the closest Vernier mark to the main scale reading is then noted, and the value of the Vernier mark is added to the main scale reading to obtain the final measurement.

Vernier calipers are available in a range of sizes and types, including digital and dial Vernier calipers. They are used for a variety of measurement tasks, including measuring the thickness of materials, the diameter of objects, and the depth of holes. Vernier calipers are a valuable tool for precision measurements in manufacturing, engineering, and science.

How to use Vernier Caliper Step by Step

Here is a step-by-step guide on how to use a Vernier caliper:

1. Familiarize yourself with the parts of the Vernier caliper. The main scale is the long, graduated scale that runs along the length of the caliper, and the Vernier scale is the smaller, sliding scale that moves along the main scale. The jaws of the caliper are used to measure the dimensions of an object.
2. Close the jaws of the caliper and make sure they are clean and free of debris.
3. Place the object to be measured between the jaws of the caliper. Make sure the object is placed flat against the jaws and is not angled or tilted.
4. Adjust the jaws of the caliper so that they fit snugly against the object being measured. The jaws should be tight enough to hold the object firmly in place, but not so tight that they damage or deform the object.
5. Read the main scale of the caliper to the nearest whole unit of measurement. For example, if the object measures 5 cm, read the main scale at the point where the jaws meet and record the measurement as 5 cm.
6. Look at the Vernier scale on the caliper. The Vernier scale is a smaller scale that slides along the main scale and has its own set of markings. Find the line on the Vernier scale that lines up most closely with a line on the main scale.
7. Record the reading on the Vernier scale that lines up with the main scale reading. The Vernier scale reading provides a more precise measurement than the main scale reading.
8. Add the main scale reading to the Vernier scale reading to get the total measurement. For example, if the main scale reading is 5 cm and the Vernier scale reading is 0.2 cm, the total measurement is 5.2 cm.
9. Release the jaws of the caliper and remove the object.
10. Clean the jaws of the caliper and store it in a safe place.

Remember to always handle the caliper carefully and use it only for its intended purpose to avoid damaging the instrument or getting inaccurate readings.

Classification of Vernier Caliper

Vernier calipers can be classified based on various factors. Some of the common classifications are:

1. Based on the number of scales:

• Single scale Vernier caliper: These calipers have only one scale, which is graduated in millimeters or inches.
• Dual scale Vernier caliper: These calipers have two scales, one graduated in millimeters and the other in inches.

2. Based on the measurement range:

• Standard Vernier caliper: These calipers can measure up to 150mm or 6 inches.
• Long jaw Vernier caliper: These calipers have longer jaws and can measure up to 300mm or 12 inches.

3. Based on the type of jaws:

• Inside Vernier caliper: These calipers have jaws that can be used to measure the internal diameter of an object.
• Outside Vernier caliper: These calipers have jaws that can be used to measure the external diameter of an object.
• Depth Vernier caliper: These calipers have jaws that can be used to measure the depth of an object.

4. Based on the material:

• Stainless steel Vernier caliper: These calipers are made of stainless steel and are more resistant to corrosion.
• Carbon steel Vernier caliper: These calipers are made of carbon steel and are less expensive.

5. Based on the accuracy:

• Standard Vernier caliper: These calipers have an accuracy of ±0.02mm or ±0.001 inches.
• High-precision Vernier caliper: These calipers have an accuracy of ±0.01mm or ±0.0005 inches.

6. Based on the features:

• Digital Vernier caliper: These calipers have a digital display that shows the measurement.
• Dial Vernier caliper: These calipers have a dial that shows the measurement.
• Depth gauge Vernier caliper: These calipers have a depth gauge that can measure the depth of an object.

Type Of Vernier Caliper

There are several types of Vernier calipers available, each with its own specialized features and applications. Here are some of the most common types of Vernier calipers:

1. Standard Vernier Caliper: This is the most common type of Vernier caliper and is used for measuring linear dimensions of an object. It has two jaws that are used to measure external and internal dimensions.
2. Digital Vernier Caliper: This type of Vernier caliper uses an electronic digital display to read the measurement, making it easier to read and more accurate. It is particularly useful when measuring small dimensions or when high precision is required.
3. Dial Vernier Caliper: This type of Vernier caliper has a dial indicator that displays the measurement on a circular dial. It is particularly useful for measuring cylindrical objects.
4. Vernier Height Gauge: This is a specialized type of Vernier caliper that is used for measuring the height of an object. It has a fixed base that is used to rest the object on and a movable arm that is used to take the measurement.
5. Vernier Depth Gauge: This type of Vernier caliper is used for measuring the depth of an object. It has a long probe that is inserted into the object and a scale that reads the measurement.
6. Vernier Caliper with Fine Adjustment: This type of Vernier caliper has a fine adjustment screw that allows for precise measurements to be taken. It is particularly useful for measuring small, delicate objects.
7. Inside Vernier Caliper: This type of Vernier caliper is used for measuring internal dimensions, such as the diameter of a hole. It has a set of pointed jaws that are inserted into the hole to take the measurement.
8. Outside Vernier Caliper: This type of Vernier caliper is used for measuring external dimensions, such as the diameter of a rod. It has a set of flat jaws that are placed around the object to take the measurement.

Vernier Caliper Least Count

The least count of a Vernier caliper is the smallest measurement that can be read and recorded with the instrument. It is a function of the number of divisions on the main scale and the number of divisions on the Vernier scale.

In a metric Vernier caliper, the main scale is typically graduated in millimeters with each millimeter divided into 10 parts (0.1 mm). The Vernier scale has 9 divisions, each of which is equal to 0.9 mm, making the total length of the Vernier scale 8.1 mm (9 x 0.9 mm). The least count of this Vernier caliper is therefore 0.1 mm ÷ 10 = 0.01 mm, which means that it can measure to the nearest hundredth of a millimeter.

In an imperial (inch-based) Vernier caliper, the main scale is typically graduated in inches with each inch divided into 16 parts (1/16 inch). The Vernier scale has 25 divisions, each of which is equal to 0.001 inch, making the total length of the Vernier scale 0.025 inches (25 x 0.001 inch). The least count of this Vernier caliper is therefore 1/16 inch ÷ 25 = 0.001 inch, which means that it can measure to the nearest thousandth of an inch.

It is important to note that the least count of a Vernier caliper is a function of the specific instrument being used and may vary depending on the number of divisions on the main scale and the Vernier scale.

Least Count Formula

The formula to calculate the least count of a measuring instrument is as follows:

Least count = Value of one main scale division ÷ Total number of divisions on the Vernier scale

For example, let's consider a Vernier caliper where the main scale is graduated in millimeters with each millimeter divided into 10 parts (0.1 mm) and the Vernier scale has 9 divisions, each of which is equal to 0.9 mm. To calculate the least count of this Vernier caliper, we can use the formula:

Least count = 0.1 mm ÷ 9 = 0.0111 mm

Therefore, the least count of this Vernier caliper is 0.0111 mm, which means that it can measure to the nearest hundredth of a millimeter.

Different parts of Vernier Caliper

A Vernier caliper is a precision measuring tool that consists of several parts. Here are the different parts of a Vernier caliper:

1. Main scale: The main scale is a long, graduated scale that runs along the length of the caliper. It is usually marked in millimeters (mm) or inches (in).
2. Vernier scale: The Vernier scale is a smaller, sliding scale that moves along the main scale. It is marked with a series of lines that correspond to the main scale graduations.
3. Jaws: The jaws of the caliper are used to measure the dimensions of an object. The outer jaws are used to measure external dimensions, while the inner jaws are used to measure internal dimensions.
4. Depth rod: The depth rod is a long, pointed rod that extends from the bottom of the caliper. It is used to measure the depth of a hole or slot.
5. Locking screw: The locking screw is used to hold the jaws in place once the measurement has been taken. It helps to prevent the jaws from moving and ensures an accurate measurement.
6. Thumbwheel: The thumbwheel is used to move the jaws of the caliper. It allows for fine adjustments to be made and makes it easier to take precise measurements.
7. Dial or digital display: Some Vernier calipers may have a dial or digital display that shows the measurement. This makes it easier to read the measurement and can be particularly useful when measuring small dimensions or when high precision is required.
8. Beam: The beam is the main body of the caliper that holds all of the other parts together. It is usually made of stainless steel or other durable materials to ensure accuracy and longevity.

Understanding the different parts of a Vernier caliper is essential for using it effectively and accurately.

Use of Vernier Caliper

Vernier calipers are used for precise measurements of linear dimensions, both internal and external. They are commonly used in fields such as engineering, manufacturing, and scientific research. Some of the common uses of Vernier calipers include:

1. Measuring the diameter of shafts or bolts
2. Measuring the thickness of sheets or plates
3. Measuring the depth of holes or slots
4. Measuring the inside diameter of cylinders or tubes
5. Measuring the outside diameter of cylinders or tubes
6. Measuring the length or width of objects with high precision
7. Checking the accuracy of other measuring tools

The accuracy and precision of Vernier calipers make them ideal for use in industries where small tolerances and accurate measurements are required. They are used in a wide range of applications, from quality control in manufacturing to scientific research and development. With proper use and maintenance, Vernier calipers can provide reliable and accurate measurements for many years.

Care and maintenance procedure of Vernier Caliper

Proper care and maintenance of a Vernier caliper can ensure its accuracy and prolong its lifespan. Here are some general guidelines for maintaining and caring for your Vernier caliper:

1. Keep the caliper clean: After each use, wipe the caliper with a clean, dry cloth to remove any dirt or debris. Avoid using water or cleaning solutions that could damage the scale or the measuring jaws.
2. Store the caliper in a safe place: When not in use, keep the caliper in a protective case or box to prevent it from being damaged or exposed to moisture or dust.
3. Check the accuracy of the caliper regularly: Use a known standard to check the accuracy of the caliper periodically. If you find any discrepancies, adjust or repair the caliper as necessary.
4. Keep the jaws clean and free from damage: The measuring jaws are the most important part of the caliper, so take care to avoid damaging them or getting them dirty. Avoid touching the jaws with your fingers, as the oil and dirt from your skin can affect the accuracy of the measurements.
5. Lubricate the moving parts: Use a small amount of lubricant on the moving parts of the caliper, such as the thumbwheel or the sliding scale, to ensure smooth movement and prevent wear and tear.
6. Avoid dropping or mishandling the caliper: Vernier calipers are delicate instruments that can be easily damaged if dropped or mishandled. Handle the caliper with care and avoid subjecting it to any unnecessary shocks or impacts.

By following these guidelines, you can keep your Vernier caliper in good condition and ensure that it provides accurate and reliable measurements for many years.

Function of main Scale in Vernier Caliper

The main scale in a Vernier caliper provides the primary measurement reading, usually in millimeters or inches. The main scale consists of a linear scale or ruler with evenly spaced marks or graduations representing units of length.

The function of the main scale is to provide the approximate measurement of an object's length or diameter, which is read off the main scale directly. The main scale is typically marked with larger divisions representing whole units of measurement and smaller subdivisions representing fractions of the units.

The Vernier scale, which slides along the main scale, is used to make more precise measurements. By lining up the Vernier scale with the main scale, the user can read the fractional part of the measurement that lies between two of the main scale graduations.

Together, the main scale and Vernier scale provide a high level of precision in measuring the dimensions of an object.

Vernier Caliper Measurement Examples

Sure! Here are some examples of how to take measurements using a Vernier caliper:

1. Outside measurement: To measure the diameter of a cylindrical object, place the object between the jaws of the Vernier caliper and gently close them until they touch the object. Then, read the main scale value that lines up with the zero line on the Vernier scale, and add the value of the Vernier scale that lines up with a scale line on the main scale.
2. Inside measurement: To measure the inside diameter of a hollow object, such as a pipe or tube, place the jaws of the Vernier caliper inside the object and gently close them until they touch the sides. Read the main scale value that lines up with the zero line on the Vernier scale, and add the value of the Vernier scale that lines up with a scale line on the main scale.
3. Depth measurement: To measure the depth of a hole or the distance between two surfaces, extend the Vernier caliper jaws to the desired length and place them into the hole or between the surfaces. Read the main scale value that lines up with the zero line on the Vernier scale, and add the value of the Vernier scale that lines up with a scale line on the main scale.
4. Step measurement: To measure the height of a step or the thickness of a block, place the Vernier caliper jaws on each side of the step or block and close them until they touch both surfaces. Read the main scale value that lines up with the zero line on the Vernier scale, and add the value of the Vernier scale that lines up with a scale line on the main scale.

Remember to read and record the measurements accurately, and take care not to exert too much pressure on the jaws, which can cause inaccurate readings.

Inside Caliper

An inside caliper, also known as a Vernier caliper, is a tool used to measure the inside diameter of an object or the distance between two internal surfaces. It is similar to an outside caliper, but with inward-facing jaws that allow for internal measurements.

Here's how to use an inside caliper:

1. Open the jaws of the inside caliper by turning the adjusting screw until they are slightly larger than the diameter of the object you want to measure.
2. Insert the jaws into the internal diameter or between the two surfaces that you want to measure.
3. Slowly turn the adjusting screw until the jaws gently touch the internal surface or the two surfaces you want to measure.
4. Hold the caliper steady and read the main scale value on the fixed jaw where it lines up with the zero mark on the Vernier scale.
5. Next, locate the Vernier scale and determine the value of the Vernier scale line that lines up with a scale line on the main scale. Add this value to the main scale value to get your final measurement.
6. Be sure to take note of your reading and units of measurement.

Remember to be gentle when using an inside caliper to avoid damaging the object being measured or the instrument itself. 

Digital Vernier Caliper parts

A digital Vernier caliper has several parts that work together to provide accurate and precise measurements. Some of the main parts of a digital Vernier caliper are:

1. Jaw: The jaws of the caliper are used to hold the object being measured. The upper jaw is fixed, while the lower jaw is movable and can be adjusted using the Vernier scale.
2. Main scale: The main scale is a linear scale or ruler with evenly spaced marks or graduations representing units of length, typically in millimeters or inches. It provides the primary measurement reading.
3. Vernier scale: The Vernier scale slides along the main scale and is used to make more precise measurements. The Vernier scale has smaller graduations than the main scale, and by lining it up with the main scale, the user can read the fractional part of the measurement that lies between two of the main scale graduations.
4. Display: The display is where the measurement readings are shown. It typically consists of an LCD screen that shows the measurement in the desired units of length.
5. Battery: A digital Vernier caliper requires a battery to power the display.
6. Locking screw: The locking screw is used to lock the movable jaw in place once the desired measurement has been obtained.
7. Depth rod: The depth rod is a small extension attached to the end of the movable jaw that allows the caliper to measure the depth of an object.
8. On/Off switch: The on/off switch is used to turn the caliper on and off.

These are some of the main parts of a digital Vernier caliper, although the exact design and components may vary depending on the specific model and manufacturer.

Degree of accuracy of Vernier Caliper

The degree of accuracy of a vernier caliper depends on the design and manufacturing quality of the caliper itself. Generally, a good quality vernier caliper should have an accuracy of ±0.02 mm or ±0.001 inch.

However, it is important to note that the accuracy of a vernier caliper can be affected by several factors, such as wear and tear, improper use, and temperature changes. Therefore, it is important to regularly calibrate and maintain your vernier caliper to ensure its accuracy.

In addition, if you require even higher accuracy, there are digital Vernier calipers available that can provide readings to a resolution of 0.01 mm or 0.0005 inch, with an accuracy of ±0.01 mm or ±0.0005 inch.