A Quiz For Radius Gauge

Key Takeaways:

  • Dimensional measurement is crucial for product quality, regulatory compliance, and safety in various industries.
  • Radius gauges and protractors are tools used in dimensional measurement.
  • Radius gauges are used to measure the radius of a curved surface, while protractors are used to measure angles.
  • Radius gauges are more accurate for measuring radii, while protractors are more suitable for measuring angles.
  • Both tools have limitations and drawbacks, such as limited accuracy and range.

Radius Gauge:

A radius gauge is a tool used to measure the radius of a curved surface, such as a fillet or corner. It consists of a set of blades or pins of different sizes that can be inserted into a groove or against a surface to determine the radius of curvature.

Radius gauges come in different shapes and sizes, often made of stainless steel.

They can be used to check the radii of tools, dies, and other mechanical components.

These gauges are highly accurate and can measure both inside and outside radii.

They are often used in conjunction with other measuring tools, such as micrometers and calipers, to ensure precise measurements.


A protractor is a tool used to measure angles, such as the angle between two intersecting lines. It is an angular measuring instrument with a least count of 1° or ½°. Protractors are commonly used in geometry, construction, and engineering to measure angles and draw angles of a specific degree.

They can measure angles of up to 180°.

A bevel protractor is a specific type of protractor that can measure angles with a least count of 5'.

While a protractor can be used to measure the angle subtended by an arc, it is not designed to measure the radius of the arc.


When it comes to measuring radii, a radius gauge is more suitable than a protractor. A radius gauge offers higher accuracy, with measurements as precise as 0.001 mm. In contrast, a protractor typically has a least count of 1° or ½°, making it less accurate for measuring radii.

While a protractor can measure angles, it is not designed to measure the radius of a curve or corner.

Therefore, a radius gauge is the preferred tool for accurate radius measurements.

However, if you need to measure angles, a protractor is the appropriate tool. It can measure angles with a least count of 1° or ½°, making it suitable for various applications in geometry, construction, and engineering.

Users and Recommendations:

Based on the features of radius gauges and protractors, here are recommendations for three possible users:

  • Pattern Maker: For a pattern maker who needs to measure radii accurately for precision machining and layout creation, a radius gauge is the best choice. Its high accuracy and ability to measure both inside and outside radii make it ideal for these applications.
  • Geometry Student: For a geometry student who needs to measure angles for assignments and drawings, a protractor is the most suitable tool. Its ease of use and ability to measure angles up to 180° make it perfect for geometry-related tasks.
  • Quality Inspector: For a quality inspector who needs to ensure the accuracy of radii and angles in manufactured products, both a radius gauge and a protractor can be useful. However, the inspector should prioritize a radius gauge for precise radius measurements, as product quality heavily relies on accurate dimensions.

Overall, the choice between a radius gauge and a protractor depends on the specific measurement needs and requirements of the user.

Looking for a radius gauge?

Choosing a radius gauge can be very difficult if you know nothing about them.

So I created this quick, newbie guide to help you:

The best radius gauge and how to choose one for you

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