what is caliper tool? types, uses, Precautions, useful Important Facts

Caliper

A caliper tool is a special tool used to measure things. It helps us find out the exact size of an object, like how long, wide, thick, or round it is. This tool is very useful when we need to be very accurate with measurements.

Calipers are usually made of strong metals like high-carbon steel or mild steel, so they last a long time and don’t break easily.

We use calipers when we want to measure a part or a job properly. For example, if someone is making a machine or fixing a car, they can use a caliper tool to check the size of its parts.

Calipers come in three main types:

1. Outside Caliper tool
   This caliper is used to measure the outside size of an object, like the thickness of a rod or the width of a pipe.
2. Inside Caliper tool
   This one helps to measure the inside size, such as the diameter of a hole or the gap between two sides.
3. Hermaphrodite Caliper tool
   This type is a little different. It is used to mark lines or find the center of a round object. It has one pointed leg and one curved leg.

Calipers are simple but very important tools. They help us do our work with care and precision.

types of Caliper

(1) Outside Caliper tool

An outside caliper is a tool that helps us measure the outer size of something, like the width or thickness of a metal rod or pipe. We use it to find out how wide something is from the outside.

Outside calipers come in different sizes like 100 mm, 150 mm, 200 mm, and 300 mm. That means we can choose the size we need depending on the job.

There are two types of outside calipers. One of them is the Simple Outside Caliper.

Simple Outside Caliper tool

This caliper is made by bending two steel strips inward and joining them at one end with a small pin called a rivet. This rivet holds the two legs together but still allows them to move. You can gently open or close the legs with your hand. When you set the legs at the right distance, the caliper holds that size.

The legs of this caliper are thicker at the top and slowly become thinner and sharper at the bottom. This makes it easy to measure even small objects neatly and accurately.

Spring Outside Caliper tool

A spring outside caliper is a tool used to measure the outer size of something, like the width of a small object.

This tool has two strong legs. A small ring-like spring is fixed at the top of these legs. This spring helps to keep the legs either open or closed. In the middle of the caliper, there is a lever and a screw. The screw has a small nut on it. When we turn this nut, it moves the legs closer together or farther apart.

This way, we can set the exact distance we want between the legs.

Once the caliper is set to a certain size, that size does not change—even if you press or move it. That means we can use the same measurement again and again without resetting it.

With this tool, we can take very accurate measurements of anything on the outside, like a rod or a pipe.

📏 Note: We also use a steel rule along with the caliper to check or compare sizes—whether it’s outside or inside.

Inside Caliper tool

An Inside Caliper is a simple tool that helps us measure things from the inside. For example, if there is a round hole or a narrow space, we can use this tool to know how wide it is. It’s perfect for checking the diameter of a bore, or the width of a groove.

🛠️ Sizes Available:
Inside Calipers come in different sizes like 75 mm, 100 mm, 150 mm, 200 mm, and 300 mm. You can choose the size that fits your work. there are two types of Caliper.

🧰 Types of Inside Calipers

There are two main types of Inside Calipers:

1️⃣ Simple Inside Caliper tool

This caliper looks a lot like the Outside Caliper. It has two legs joined at the top with a strong rivet. This joint is made in such a way that you can open or close the legs by using a little force – not too tight, not too loose.

The tips of the legs are thin and slightly bent outward. Why? Because this helps the legs easily go inside the space you want to measure – like a hole or a groove. Once inside, you can gently open the legs to match the inner size and then measure it.

Spring Inside Caliper tool🌸

A Spring Inside Caliper is a tool used to measure the distance between two inner sides of something, like the inside of a hole or a pipe. It looks like a pair of legs joined at the top, and it works in a special way.

At the top of both legs, there is a round spring. This spring is held safely in a small groove, so it doesn’t move out of place. It helps the caliper open and close smoothly.

To keep the legs steady, a rivet is fixed between them. This acts like a support. Also, there’s a screw passing through the legs with a nut on it. When you turn the nut, the legs either move closer together or spread apart — just like how you open and close your fingers.

This is how you set the exact size you want to measure.

🟢 Note: The tips of both legs are bent slightly outward at an angle of 45°. This shape helps the caliper fit neatly inside the object you want to measure.

Hermaphrodite Caliper tool

A Hermaphrodite Caliper is a special tool used in workshops. It has two legs — one leg is straight and pointed, and the other leg is bent.

This tool is very helpful when we need to draw a line in the middle of a round object, like a rod or a shaft. The pointed leg is placed on the edge of the object, and the bent leg helps mark the center line.

If needed, the bent leg can be changed to bend outwards instead of inwards.

This caliper is also known by other names like:

• Jenny Caliper
• Odd Leg Caliper
• Lag and Point Caliper

No matter what we call it, it helps us do accurate marking work — and that makes every job neater and better.

Uses of Hermaphrodite Caliper tool

A hermaphrodite caliper is a special tool used in workshops. It looks a little different from other calipers because it has one pointed leg and one curved leg. Even though it looks simple, it does very useful work.

Here are the main ways we use a hermaphrodite caliper:

To draw parallel lines:
It helps in drawing lines that run side by side, either along the outside edge or the inside curve of a metal or wooden piece. These lines are always the same distance from the edge, which makes the work neat and correct.

To mark the center of round objects:
When we have a circular rod or shaft, the hermaphrodite caliper helps find the middle point. This is very useful when we want to drill a hole right in the center.

To mark even spaces:
When we need to draw more than one line at equal distances from each other, this tool helps us do that quickly and easily.

Figure: Drawing a parallel line along the outer edge of a metal piece using a hermaphrodite caliper.

Let me know if you want the same style for other tools too!

Precautions While Using a Caliper tool

A caliper is a tool that helps us measure things carefully. But to use it properly, we must take some safety steps. These small steps help us get the correct result and keep the tool safe too. Let’s see what we should keep in mind:

Keep the Tip Sharp and Clean
The tip of the caliper should be sharp, smooth, and clean. If it is dirty or damaged, it may not measure correctly.

Use the Right Caliper for the Right Job
Always choose a caliper that matches the size and type of the item you want to measure. This makes your work easier and better.

Hold It Gently but Firmly
Do not press the caliper too hard. Hold it gently so it does not hurt the object or go out of shape.

Check Before You Measure
Make sure the caliper is working well before using it. Move it and see if it opens and closes smoothly.

Use Both Hands if Needed
If the object is big or the caliper is long, use both hands to hold it steady.

Do Not Drop the Caliper
Keep the caliper safe. If it falls, it can break or stop working properly.

Store It in a Safe Place
After using, wipe it clean and keep it in its box or a soft cloth so it stays safe and lasts long.

Do Not Use on Moving Objects:
Never use a caliper on a part that is spinning or moving. This is very dangerous and can break the caliper or hurt your hand.

Firm Joint Should Be Just Right:
If you are using a firm joint caliper, its rivet (the joint) should not be too tight or too loose. It should move smoothly and stay in place when you let go.

Keep Legs Straight in Hermaphrodite Caliper:
When using a hermaphrodite caliper, keep both legs straight and equal. They should stand at a right angle (like the letter “L”) to the object being measured.

FAQ