Important Point

## What Is Bevel Protractor?

A bevel protractor is a device that consists of a graduated circular scale with a pigmented arm used to measure or make angles. In geometry, a protractor is a spherical or semicircular device that is used to measure an angle or circle. The units measured are normally degrees.

Some protractors are half-discs that have existed since ancient times. A more advanced protractor, such as the bevel protractor, is one or two swinging arms, which help measure the angle.

The device is capable of measuring angles with a minimum count of 5′ or 5 minutes. It is used to measure the angles of any workpiece. It is used for various items such as jigs.

Sometimes the bevel protractor is attached to the Vernier scale to give more accurate readings.

Bevel protractor has a very important role in mechanical architectural drawing. The use of software such as CAD is reducing the general use of bevel protractors. Bevel protractors are used to test angles. It is used for various mechanical and engineering-related applications.

## Parts of Bevel Protractor:

### #1. Swivel Plate

The swivel plate rotates on the dial. This swivel plate has a vernier scale that is integrated into it.

### #2. Magnifying Glass

A magnifying glass is also present on the version scale in the swivel plate. These magnifying glasses are used to see the value of angles on the main scale and, more clearly, the Vernier scale.

### #3. Vernier Scale

The Vernier scales are fixed on the swivel plate, & it moves along the swivel plate. The Vernier scale gives the remaining angle in minutes. There are 60 minutes in 1 degree. It is added to the Vernier scale bevel protractor to increase the accuracy of angle measurement.

In the center, the Vernier scale has a zero. The Vernier scale has 12 partitions on either side of zero, and each division is of 5 minutes. So there’s are 60 minutes on each side of zeros on the Verniers scale.

### #4. Angle locking screw

This angle locking screw is used to locks the bevel protractor at a fixed angle so that the locking angle can be measured without any disturbances.

This angle prevents the swivel plate from rotating in relation to the locking screw dial or dial scale.

### #5. Dial

This is the basis of the bevel protractor on which the other parts are present. The main scale or dial scale is marked on this dial.

### #6. Dial Scale

This dial scale is the core of the bevel protractor. It has a graduated level of angle from a value of 0 degrees to 360 degrees. At this graduation, every tenth degree is counted.

It is divided into four divisions of 360 degrees, every 90 degrees.

### #7. Blade

This blade is made of high carbon steel. This blade is a thin blade. These blades are either 150 mm or 300 mm, depending on the bevel’s protractor.

When the blades are parallel to the stock, the zero of the Vernier scale corresponds to the zero of the main scales or the dial scale.

The blade has one end of 45 degrees, and the other has an angle of 30 degrees so that 45 degrees & 30 degrees can be directly measured using these edges.

### #8. Blade Lock Screw

Blade locking screws are available to lock the blade at a fixed location. This screw is used when we determine the required length of the blade along the surface of the workpiece.

### #9. Stock

The bevel is one of the contact surfaces in the protractor when measuring the stock angle. Stocks are the integrated part of the dial. The dial also rotated with respect to the blade as it moves, & the angle value changes in the dial scale. The job or workpieces whose angle is to be measured is placed in contact with this stock on one side. The other side of the job surfaces whose angles are to be measured is placed in contact with the blade. The blade of the bevel protractor goes inside the slot in the stock.

Also, Read: What Is a Flame in Gas Welding? | Types of Flames in Gas Welding

## Working of Bevel Protractor:

First, the workpiece, whose angles are to be measured, is placed between the blade and the stock of the bevel protractor. One side of the surface measuring the angle is placed in contact with the blade, and the other sides are in contact with the stock.

When the workpiece comes in contact with the blade properly, and the blade is properly placed on the workpiece, the blade is closed using a blade locking screw. After that, when the measured surface comes fully in contact with the stock and blade, the angle is fixed using angle locking screws.

Now we see the values in the main scales, which coincides with the zero of the Vernier scale. The value we read from the main scale gives the angle in degrees. The angle in the main scale, to be more precise, comes just before the zero points of the Vernier scale.

To obtain the angle more accurately, we will now obtain the remaining angle in minutes. To do this, we look at the line of the Vernier scale, which coincides perfectly with the line of the main scale.

After obtaining that line, we see the position of the line in the Vernier scale. Then the minute of the angle measurements is calculated by multiplying the position of the coincident line of the Vernier scale with 5 (five).

Then finally, the angle measured using the bevel protractor is noted in degrees and minutes. Thus, we measure the angle very accurately using a bevel protractor.

## Advantages of Bevel Protractor:

- It can accurately measure angles up to 5 flatter and can measure angles up to 360 degrees.
- It gives very accurate measurements.
- It is used to set up and test to bear angles in very close proximity.

## Applications of Bevel Protractor:

- The bevel protractor is used to probe the V block.
- It is used to examine the bevel face inside the ground surface.
- It is also used to measure acute angles.

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