Bevel Protractors – Definition, Range, and How to Use it?

Introduction to Bevel Protractor

Bevel protractor is an instrument that we use for measuring the angles of the objects. We see people using it with various objects that include jigs. Whereas, this occurs when we produce engineering/machine drawings.

Unlike a normal protractor, we adjust a bevel protractor for fitting an angle. Its base is present on the bottom side of the angle, whereas the blade moves to match the opposing side. Various bevel protractors will have a vernier scale on them that normally exists underneath the degree scale.

bevel protractor

What is Protractor?

A protractor is an instrument we use for measuring. It is typically made up of transparent plastic or maybe glass, for doing a measurement of angles. Mainly the protractors measure the angles in degrees. The radian-scale protractors measure the angles in the radians.

Many precision protractors further divide the degrees into the arcminutes. We use them for a variety of mechanical and engineering-related applications. Its most common use is in the schools for the students, we all know this, using it in the geometry classes in the mathematics class is very common and usual.

What is Bevel Protractor and Bevel Protractor Range?

A bevel protractor is an instrument that is graduated spherical protractor with one pivoted arm that we use for making off the angles. Sometimes the vernier scales have an attachment for giving more precise readings.

It plays a very important role in the mechanical and architectural drawing, although its general use is decreasing with the availability of the modern drawing software or CAD.

The bevel protractor is useful for establishing and testing the angles to very close tolerances. It reads to 5 arcminutes and can also measure angles from 0 degrees to 360 degrees.

The bevel protractors have a beam, a graduated dial and a blade that has a connection with a swivel plate (with the vernier scale) by the thumb nut and the clamp. When the edges of the beam and the blade are parallel, a small mark on the swivel plate coincides with the 0 lines on the graduated dial.

To measure an angle between the beam and the blade having an angle of 90 degrees or less. The reading might come from the graduation number on the dial indicated by the mark present on the swivel plate.

For measuring an angle of over 90 degrees, we have to subtract the number of the degrees as indicated on the dial from 180 degrees. However, as the dial is graduated from opposite 0 marks to 90 degrees each way.

How to Use Bevel Protractor?

  • Firstly, unscrew the large clamp on the front part of the protractor. It loosens the blade so that we can swivel it.
  • Align the base of the protractor on one side of an angle, and then swivel the blade for making the other side of the angle.
  • Tighten the huge clamp.
  • Spot the zero on the vernier scale. The vernier scale is smaller on the inner side of the protractor.
  • Read the number of the degrees present on the main scale, directly above the zero present on the vernier scale. For example, the zero that is on the vernier scale lines up with the mark of 85 degrees.

Solved Question for You

Ques. Which of the following statement is correct about the adjustable blade?

a) The adjustable blade has an attachment with the main body.
b) The adjustable blade is capable of rotating freely about the centre.
c) The adjustable blade is capable of rotating freely about the free edge.
d) The adjustable blade is having an attachment with a base plate.

Ans. b) The adjustable blade is capable of rotating freely about the centre.

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