Definition of Vernier caliper, definition | types, least count, principal?

Vernier caliper:

Mechanical Instrument

Vernier caliper: A Vernier caliper is a precision measuring instrument used to accurately measure linear dimensions. It consists of a main scale, a sliding Vernier scale, and a depth gauge. The main scale is a long, graduated ruler with markings in millimeters or inches that are numbered in increments of 1 or 0.1 units.

The sliding Vernier scale is a smaller ruler that slides along the main scale and has markings that are slightly offset from those on the main scale. These offset markings allow for more precise measurements to be made, down to a fraction of a millimeter or inch.

To use a Vernier caliper, the user positions the object being measured between the jaws of the caliper and slides the Vernier scale until it makes contact with the object. The user then reads the measurement from the main scale where it aligns with the Vernier scale markings.

Types of Vernier caliper:

1. standard Vernier caliper.

2. Digital Vernier caliper.

1. Standard Vernier caliper: 

Standard Vernier Calipers are commonly used in engineering, manufacturing, and scientific research applications where accurate measurements are critical. They are available in a range of sizes and can measure both inside and outside dimensions, as well as depths and steps.

It's least count is 0.02mm.

Construction:

Main body:- The main body of a Vernier caliper is typically made of high-quality stainless steel. It provides the backbone for the instrument and contains the scale markings.

Fixed Jaw:- The fixed jaw is an immovable part of the caliper that is attached to the main body. It is used to measure the outside dimensions of an object.

Movable Jaw:- The movable jaw slides along the main body and is used to measure the internal dimensions of an object. It is attached to the Vernier scale.

Vernier scale:- The Vernier scale is a smaller scale located on the movable jaw. It is divided into smaller units than the main scale, and the divisions are arranged in such a way that they are slightly offset from the main scale. This allows for more accurate readings to be taken.

Main scale:- The main scale is located on the main body of the caliper. It is graduated in either millimeters or inches, depending on the model of the caliper.

Locking screw:- The locking screw is used to lock the movable jaw in place once a measurement has been taken. This prevents any movement of the jaws, which could result in an inaccurate reading.

Depth rod:- Some Vernier calipers are equipped with a depth rod, which extends from the end of the caliper and allows for accurate depth measurements to be taken.

Overall, the construction of a standard Vernier caliper is designed to provide a precise and accurate measurement tool that can be used in a wide range of applications. 

Working principle of standard Vernier caliper:

A Vernier caliper is a precision measuring tool used to measure the distance between two opposite sides of an object. The standard Vernier caliper consists of two main parts: the main scale and the vernier scales.

1. The main scale is a long, straight ruler with a fixed jaw at one end and a sliding jaw at the other. The fixed jaw is usually located at the bottom of the caliper and does not move, while the sliding jaw can be moved along the main scale by turning a thumbwheel or a screw. The main scale is graduated in millimeters or inches, depending on the unit of measurement used.
2. The vernier scale is a small, sliding scale that is attached to the sliding jaw of the caliper. The vernier scale has a number of equally spaced divisions that are slightly smaller than the divisions on the main scale. These divisions are called vernier divisions.
3. When the caliper is closed, the vernier scale is aligned with the main scale so that the zero on the vernier scale lines up with the zero on the main scale. As the sliding jaw is moved along the main scale to measure an object, the vernier scale moves relative to the main scale. The distance between the zero on the main scale and the first vernier division that lines up with a division on the main scale indicates the measurement to the nearest tenth of a millimeter or thousandth of an inch.
4. The principle of the vernier scale is based on the idea of the least count. The least count is the smallest measurement that can be made with a measuring tool. In the case of the vernier caliper, the least count is determined by the distance between two adjacent vernier divisions. This distance is calculated by dividing the distance between two adjacent divisions on the main scale by the number of divisions on the vernier scale.

2. Digital vernier caliper: 

A digital vernier caliper is a measuring tool used in engineering, metalworking, and other precision industries to accurately measure the dimensions of an object. It is a type of caliper that uses a digital readout to display the measurement instead of a traditional scale. It's least count is 0.01mm.

The digital vernier caliper consists of two jaws, one fixed and the other movable, which slide along a beam. The jaws can be moved by a screw mechanism or a thumb wheel, and the distance between them is read from a digital display. The caliper can measure internal dimensions (such as the diameter of a hole), external dimensions (such as the diameter of a shaft), and depth measurements.

The accuracy of a digital vernier caliper depends on the quality of its construction and the resolution of the digital display. Some models can measure to a resolution of 0.01mm or 0.0005 inches. Digital vernier calipers are typically made from stainless steel or other high-strength materials to ensure durability and accuracy over time.

Construction:

Main scale: This is the long, fixed scale that runs along the length of the caliper. It is usually divided into centimeters and millimeters or inches and fractions of an inch.

Vernier scale: This is a short, movable scale that is attached to the upper jaw of the caliper. It has ten divisions that are slightly smaller than those on the main scale. The vernier scale enables measurements to be taken to a higher degree of precision.

Upper jaw: This is the movable jaw that slides along the main scale. It is attached to the vernier scale, which moves along with it.

Lower jaw: This is the fixed jaw that does not move along the main scale. It is located at the bottom of the caliper and is used to hold the object being measured.

Locking screw: This is a screw that is used to lock the upper jaw in place once the measurement has been taken.

Depth rod: This is a rod that can be attached to the lower jaw to enable measurements of the depth of holes or other recessed areas.

Thumb wheel: This is a small wheel that is used to move the upper jaw along the main scale with greater precision.

The construction of a standard vernier caliper involves precise machining of the various parts, including the main scale, the vernier scale, the jaws, and the locking screw. The scales are usually engraved or etched onto the surface of the metal, while the jaws are machined to a high degree of accuracy to ensure that they can slide smoothly and evenly along the main scale. The thumb wheel is also carefully designed to provide precise control over the movement of the upper jaw. Once all the parts are assembled, the caliper is tested and calibrated to ensure that it provides accurate and consistent measurements.

Working principle of digital Vernier caliper:

The working principle of a digital vernier caliper is based on the principle of a Vernier scale, which was invented by Pierre Vernier in the 17th century.

1. The digital vernier caliper consists of two jaws, one fixed and one movable, which slide along a graduated scale. The jaws are used to grip the object being measured, and the scale is used to read the measurement. The scale is marked with a series of fine lines that represent the measurement increments. The movable jaw is mounted on a sliding scale called a Vernier scale, which is also marked with fine lines.
2. When the jaws of the caliper are closed, the Vernier scale is moved so that the zero line on the Vernier scale aligns with the zero line on the main scale. As the jaws are opened to measure an object, the Vernier scale slides along the main scale. The distance between the zero line on the main scale and the zero line on the Vernier scale is known as the "vernier constant" and represents the smallest measurement increment of the caliper.
3. To read a measurement, the position of the Vernier scale relative to the main scale is observed. The line on the Vernier scale that best aligns with a line on the main scale represents the measurement. The digital display on the caliper converts the position of the Vernier scale into a digital reading that is displayed in the selected units of measurement, such as millimeters or inches.