Bevel Protractor Definition, 6 Types, Range, Construction, Advantages, Disadvantages & Application [PDF]

bevel protractor
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Introduction to Bevel Protractor

A bevel protractor is a measuring instrument that is commonly used in engineering, woodworking, and metalworking. It is used to measure angles with a high degree of accuracy and is typically used to measure angles on machined parts or in the construction of mechanical devices.

History of Bevel Protractor

The bevel protractor was first developed in the early 20th century by the Swiss company TESA SA. The company was founded in 1941 and began producing the bevel protractor shortly thereafter. Since then, the bevel protractor has become a standard tool in many industries.

bevel protractor
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Inventor of Bevel Protractor

The bevel protractor was invented by Rudolf Geßwein(Gesswein), a Swiss engineer and businessman who founded TESA SA. Geßwein(Gesswein) was born in 1878 and trained as a mechanical engineer. He founded TESA SA in 1941 and began producing the bevel protractor shortly thereafter.

Class Of Instruments

The bevel protractor is classified as a precision measuring instrument. It is typically made from high-quality materials, such as stainless steel, and is designed to provide accurate measurements with a high degree of repeatability. Other instruments in this class include micrometers, calipers, and height gauges.

What Is a Bevel Protractor?

A bevel protractor is a measuring tool used to measure angles in mechanical and engineering applications. It consists of two main parts: a base and a blade. The base is usually a flat surface with a scale marked in degrees, while the blade is connected to the base at one end and can be rotated to measure angles.

bevel protractor
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The blade of a bevel protractor is usually long and thin, with a Vernier scale engraved on it. The Vernier scale allows for very precise measurements to be made, with an accuracy of up to 5 minutes (1/12 of a degree).

Bevel Protractor Range

The range of a bevel protractor refers to the maximum angle that can be measured using the instrument. Bevel protractors typically have a range of 0 to 360 degrees, allowing them to measure any angle within a full circle.

Universal bevel protractor
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However, some bevel protractors may have a smaller range, such as 0 to 90 degrees or 0 to 180 degrees, depending on the intended application. For example, a bevel protractor designed for woodworking may have a smaller range, as most angles in woodworking are between 0 and 90 degrees. It is important to choose a bevel protractor with the appropriate range for the task at hand, as using an instrument with a limited range may result in inaccurate measurements

How To Use A Bevel Protractor?

  • Set up the base: Place the bevel protractor on a flat surface and ensure that the base is level. The base should be positioned perpendicular to the angle you want to measure.
  • Align the blade: Align the blade of the bevel protractor with the surface of the object or part you want to measure. The blade should be parallel to the surface.
  • Read the angle: Rotate the blade until it aligns with the angle you want to measure. The degree markings on the base and blade should be aligned. The Vernier scale can be used to obtain a more precise reading.
  • Lock the blade: Once you have obtained the desired angle reading, lock the blade in place to prevent it from moving.
  • Check the measurement: Double-check the angle measurement to ensure that it is accurate.
  • Record the measurement: Record the angle measurement for future reference or use in calculations.

It’s important to note that when using a bevel protractor, we should take care to avoid parallax errors which means that you should view the angle measurement directly from above to avoid any discrepancies due to viewing the measurement at an angle. Additionally, you should ensure that the bevel protractor is not subjected to any external forces or vibrations that could affect the accuracy of the measurement

The Types of Bevel Protractors

  • Universal Bevel Protractor: This type of bevel protractor is the most commonly used in engineering and mechanical applications. It has a Vernier scale and a blade that can be rotated 360 degrees, allowing it to measure angles in any plane.
  • Optical Bevel Protractor: This type of bevel protractor uses an optical system to provide a more precise measurement of angles. It typically has a magnifying lens and a light source to enhance the visibility of the scale and markings.
Universal bevel protractor
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  • Digital Bevel Protractor: This type of bevel protractor uses an electronic display to provide a precise angle measurement. It typically has a blade that can be rotated and a digital readout that displays the angle measurement.
  • Vernier Bevel Protractor: This type of bevel protractor uses a Vernier scale to provide a more precise measurement of angles. It typically has a blade that can be rotated and a Vernier scale engraved on the blade to provide a more precise reading.
  • Dial Bevel Protractor: This type of bevel protractor uses a dial indicator to provide a more precise measurement of angles. It typically has a blade that can be rotated and a dial indicator that displays the angle measurement.

The parts of a bevel protractor

  • Base
  • Blade
  • Vernier Scale
  • Clamping Mechanism
  • Protractor Head
  • Degree Scale
  • Locking Screw
  • Magnifier
  • Light Source
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construction of a Bevel Protractor

  • Base: The base of a bevel protractor is typically made from a flat and sturdy material, such as cast iron or steel. It provides a stable platform for the instrument to rest on during use.
  • Blade: The blade of a bevel protractor is typically made from high-quality steel that is both durable and lightweight. It is attached to the base and can rotate to measure angles.
  • Vernier Scale: The Vernier scale is typically engraved directly onto the blade of the bevel protractor. It consists of a series of graduated marks that allow for precise angle measurements.
  • Clamping Mechanism: The clamping mechanism is used to lock the blade in place once the desired angle has been set. It typically consists of a locking screw or lever that is tightened to hold the blade in place.
  • Protractor Head: The protractor head is located on top of the blade and can be adjusted to measure angles in different planes. It typically consists of a movable arm that can be adjusted to various positions and locked in place using a locking screw or lever.
  • Degree Scale: The degree scale is typically marked directly onto the base of the bevel protractor. It shows the angle being measured and is used in conjunction with the Vernier scale for precise angle measurement.
  • Magnifier: Some bevel protractors may include a small magnifying lens located on the protractor head to enhance the visibility of the degree scale.
  • Light Source: Some bevel protractors may also include a small light source located on the protractor head to provide illumination for easier reading of the degree scale.

It’s important to note that the specific parts of a bevel protractor may vary depending on the manufacturer and model of the instrument. However, the basic design and functionality will remain the same.

bevel protractor Consruction
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Main Scale & Vernier Scale Reading

The main scale on a bevel protractor is typically marked in degrees, with each degree divided into smaller increments. To read the main scale, align the base of the protractor with the reference surface and rotate the blade until the protractor head is lined up with the angle being measured. The degree marking on the base directly beneath the protractor head represents the angle measurement.

The Vernier scale on a bevel protractor is typically located on the blade and consists of a series of graduated marks that allow for more precise angle measurement. The Vernier scale is designed to align with the main scale and provide an accurate measurement of the angle being measured. To read the Vernier scale, locate the zero mark on the Vernier scale and note the number that lines up with a mark on the main scale. Then, read the smallest division on the Vernier scale that lines up with a mark on the main scale.

This value represents the fractional part of a degree that the angle is off from the nearest whole degree. For example, if the main scale reads 30 degrees and the Vernier scale reads 0.2, the total angle measurement is 30.2 degrees. It’s important to note that the exact design and layout of the Vernier scale may vary depending on the specific bevel protractor, but the basic principles of alignment and measurement remain the same.

Advantages of a bevel protractor

  • Provides precise and accurate angle measurement
  • Versatile and suitable for a range of applications
  • Easy to use and require minimal training or experience
  • Durable and long-lasting
  • Lightweight and portable

disadvantages of a bevel protractor

  • The limited range for angle measurement
  • Precision may be affected by factors such as instrument quality and user accuracy
  • Limited functionality for other types of measurements or applications
  • Potential for inaccuracy due to user error
  • Can be relatively expensive compared to other measuring instruments

Applications of a bevel protractor

  • Metalworking: Bevel protractors are commonly used in metalworking to measure and mark angles for cutting, welding, and fabrication.
  • Woodworking: Bevel protractors can be used in woodworking to measure and mark angles for cutting, joinery, and other tasks.
  • Engineering: Bevel protractors are commonly used in engineering to measure angles for design, analysis, and construction.
  • Inspection and Quality Control: Bevel protractors can be used in inspection and quality control applications to verify the accuracy of angles and other geometric measurements.
  • Machining: Bevel protractors can be used in machining applications to set up tools, measure angles, and check the accuracy of parts.
  • Architecture and Construction: Bevel protractors can be used in architecture and construction to measure and mark angles for layout, framing, and other tasks.

faq

How to read bevel protractors?

To read a bevel protractor, align the base with the surface and adjust the protractor head to the desired angle. Lock it in place and read the main scale for the whole number of degrees and the Vernier scale for the fraction of a degree. Add them to get the total angle measurement. Make sure to properly align and secure the instrument to ensure accuracy.

What are the types of bevel protractors?

The two main types of bevel protractors are dial bevel protractors and digital bevel protractors. Dial bevel protractors use a dial indicator to measure angles, while digital bevel protractors use electronic sensors.

What is a universal bevel protractor?

A universal bevel protractor is a type of bevel protractor that has a movable arm that can be adjusted to measure angles in a wide range of applications. It is commonly used in metalworking, engineering, and construction for precise angle measurements and layout work. The universal bevel protractor can measure angles from 0 to 360 degrees and can be used to measure both internal and external angles.

How to measure the bevel angle?

To measure a bevel angle, place the blade or base of the bevel protractor on the surface to be measured and align it with the edge of the material. Adjust the protractor head to the desired angle and lock it in place. Read the main scale and Vernier scale on the instrument to determine the angle measurement. If necessary, use a magnifier to enhance the visibility of the Vernier scale.

conclusion

In conclusion, a bevel protractor is a precision measuring instrument used to measure angles in metalworking, engineering, and construction applications. There are two main types of bevel protractors: dial bevel protractors and digital bevel protractors. The instrument consists of a blade or base, a protractor head, a locking mechanism, and a main and Vernier scale. To use a bevel protractor, align the instrument with the surface to be measured, adjust the angle, and read the scale. The universal bevel protractor is a type of bevel protractor that has a movable arm for measuring angles in a wide range of applications.

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