In projects where accurate measurement must prevail, a vernier caliper must come into use. The lathe machinist can relate better because 95% of lathe operations are measured using a caliper. This is to say, it is a special tool for lathe operators.
Vernier Caliper is a precision measuring instrument used to measure the internal and external dimensions of an object. Its two major parts include a fixed jaw and a movable jaw.
The movable jaw is used to measure the inside of the object while the fixed jaw is used to measure the outside. Vernier calipers can measure smaller values from about 0.1 mm.
Vernier calipers are used in different fields and applications including science, construction, engineering, and manufacturing. They are used for the same purpose which is to take measurements. Learn about Micrometer Screw Gauge here!
Now, let’s go deep to explain what a vernier caliper is, its parts, diagram, and how to read it!
Contents
What is a Vernier Caliper?
Vernier caliper which is also known as the vernier scale is a measuring device that is used to get a precise measurement of linear dimensions. In other words, it measures a straight line between two points.
It is also applicable when trying to take the dimension of round objects and can also measure the depth of a hollow part. This is to say, a vernier caliper can be used to take three different measurements, which include, depth, width, and linear parts.
It can also be seen as a visual aid for taking an accurate measurement reading between two graduation markings on a linear scale. It is done by increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error.
The vernier caliper or scale was invented in 1631 by French mathematician Pierre Vernier. Its part is used together with the main scale, given precise measurements at proper use.
They are useful tools that must be found in an engineer’s toolbox. It contains a fixed main scale and a moving vernier scale. This main scale is labeled in millimeters or tenth of an inch. The precise measurement of a vernier caliper is due to its ability to take a reading typically 0.02mm or 0.001 inch.
The resolution of a vernier caliper is the smallest distance that the caliper can measure. The resolution of imperial vernier calipers is usually 0.001 in, whereas the resolution of metric calipers is either 0.05mm or 0.02mm. Typically, the caliper’s resolution is indicated at the end part of the vernier scale.
Vernier Caliper Parts
The various parts of a vernier caliper are main scale, vernier scale, fixed jaw, moveable jaw, zero adjusment screw, locking screw, lower jaws, upper jaws, depth screw, thumb screw, lock screw, and lock screw.
- Main Scale: this scale is used to measure the overall length of an object.
- Vernier scale: it is used to measure small increment of an object’s length.
- Fixed jaw: is a stationary jaw used to measure the outside of an object.
- Movable jaw: is a moving jaw used to measure the inside of an object.
- Zero adjustable screw: is used to make sure the vernier caliper is at zero before taking any measurement.
- Locking Screw: is used to ensure the movable jaw is in place after taking a measurement.
- Lower jaw: is used and designed to secure grip, and measure the outer dimensions like diameter, width, and length.
- Upprt jaw: is used for measuring inner dimensions. They are open to touch the edges of objects like hollow pipes and jars for accurate readings.
- Depth screw: is used to measure jar depth with the depth rod at the end of the main scale.
- Thumb screw: is used to ensure a secure grip for easy sliding of the jaws.
- Lock screw: is used to secure the jaw in place when the object is firmly held, to facilitate accurate reading.
Diagram of a Vernier Caliper
How to Use and Read a Vernier Caliper?
To use a vernier caliper, ensure the instrument is properly zeroed, which is done by loosen the locking screw and adjust the movable jaw to reach the zero mark on the vernier scale to align with the zero on the main scale.
Then place the object to be measured between the fixed and movable jaws. tighten the locking screw to secure the movable jaw in place.
Finally, reading the measurement from the main scale and the vernier scale, the main scale will give you the overall length of the object. The vernier scale gives the small increments of length.
To ensure and varify a accurate measurement on a vernier caliper, you must make sure the main and vernier scale aligned and there is no nothing in between. Zero error is eliminated when both scale read zero.
Place a ball between the scale jaws, aligning the 0 mark on the vernier scale with the main scale to get the main scale reading. Knowing the point on the vernier scale aligned with the main scale for the vernier scale reading.
This readings involve decimals, which occur after the main number represents the verner scale reading.
Read more: Types of Measuring and marking-out tools and their uses
Measuring Range and Tolerance of a Vernier Caliper
A vernier caliper measurement range is the difference between the largest and smallest value that a caliper can measure. The caliper range is sometimes called the maximum capacity of a caliper, which is equal to the length of the main scale. Most vernier calipers have a range of 6 inches (300mm). However, calipers are available in smaller and larger ranges.
Discussing tolerance or instrument error vernier calipers are good at that, same as micrometers. They are tools purposely designed for low tolerance measurement. Low-tolerance measuring tools are known for their very accurate measurements.
As for vernier calipers, their instrument error is mostly +- 0.03mm (+- 0.0015 in). As you see that is quite tolerated, with the capability of measuring outside dimensions, inside dimensions, and depth. Some calipers with incorporate the Quadri feature are used to take step measurements.
Least Count of a Vernier Calliper
The least count of a venier capliper is the smallest measurement the instrument can make. It can be calculated by dividing the smallest division on the main scale by the number of divisions on the vernier scale. The mathematical formula for the Least Count of Vernier Calliper is,
VC = 1 MSD – 1 VSD
Read more: Common types of precision measuring instruments
Watch the video below to learn the working of a vernier caliper:
Digital Vernier Calliper
Finally, the advancement of technology helped with the development of the Digital Vernier Calliper. These digital calipers offer very accurate measurements, even more than the traditional ones. But it is a little more expensive, maybe that’s why users prefer traditional calipers.
The digital vernier caliper takes measurements with a series of capacitance sensors that move around the beam length. The sensor will detect a change in the electrical charge when a change occurs in the distance of the jaws.
FAQs on Vernier Caliper
What is a Vernier Caliper?
Vernier Calliper is a precision measuring instrument used to measure the internal and external dimensions of an object. Its two major parts include a fixed jaw and a movable jaw.
How does a Vernier Caliper Work?
A vernier Calliper works on the principle of Vernier scale, which provides accurate measurement readings. The main scale measures whole units, while the vernier scale slides along the main scale and provides additional fractional readings.
What are Parts of a Vernier Caliper?
The parts of a vernier caliper are the main scale, vernier scale, jaws for measuring outer dimensions, and depth gauge for measuring depths. It also includes a locking screw to hold measurements in place.
How to Read Measurements on a Vernier Caliper?
To read measurements on a vernier Caliper, align the object between the jaws and read the main scale reading at the zero mark of the vernier scale. Then, identify the graduation line on the vernier scale that perfectly aligns with a graduation line on the main scale. The value indicated by the aligned lines on the vernier scale represents the fractional part of the measurement.
What are Applications of Vernier Calipers?
Calipers are used in various fields, including engineering, manufacturing, and science, where precise measurements are required. They are commonly used for measuring dimensions of objects, thickness, inner and outer diameters, as well as depth measurements.
That is all for this article, where i explained what a vernier caliper is, its parts, diagram, and how to read it. I hope it was helpful, if so, kindy share with others. Thanks for reading, see you around!