Types of Scales Used in Engineering Drawing

Engineers Rail welcomes you to another segment of the knowledgeable journey, where you will learn the Types of Scales in Engineering Drawing.

If you’re looking for the same thing, join me and follow along as I walk you through this course. So, without further delays let’s get started…

Let’s begin with the fundamentals-

What is Scale?

A scale is the ratio of the linear dimension of an object’s element as shown in a drawing to the actual dimensions of the same object’s element.

Or, A scale is a measuring device that is used to determine a person’s weight. The most prevalent scales found in our environment are digital scales.


Now, Let’s move to the type of engineering drawing scales.

Types of Scales in Engineering Drawing-

There are several types of Engineering drawing scales. They are-

  1. Plain Scale
  2. Diagonal Scales
  3. Comparative Scale
  4. Vernier Scale
  5. Scale of Chords

engineering drawing scales types

Plain Scale-

A plain scale is just a line that has been divided into a specific number of equal pieces, the first of which has been further subdivided into smaller portions. It can be used to represent two units, a unit, or a fraction of a unit.

Plain scale is used in engineering drawings to measure up to two units in a row. For instance, metre and decimetre, feet and inches, and so on.

plain scale diagram

Diagonal Scale-

Three units are represented by a diagonal scale. They are-

  • Main Unit
  • Sub-Unit
  • Sub-Division

The diagonal primary is used to divide a small unit of a plain scale. The scale is called the diagonal scale because the third unit of scale is determined using this diagonal.

When three successive units of measurement are required, a diagonal scale is utilised. The measurement accuracy of a diagonal scale is higher than the Plain scale. For instance- Metre, decimetre, and centimetre.

diogonal scale diagram


Comparative Scale-

A comparison scale is a pair of scales with the same representative fraction but graduated to read measurements in several unit systems. Depending on the situation, comparative scales can be built as plain or diagonal scales.

For Instance, Through a comparative scale- a map or graphic made on a scale reading miles and feet can be estimated directly in kilometres and hectometers.

Comparative Scale diagram

Read Also- Ten Different Types of Spring and its Applications

Vernier Scale-

A vernier scale is a metric scale that measures three successive units. As a result, the vernier scale’s measurement accuracy is equivalent to the diagonal scale. In engineering drawings, vernier scales are used to show distances inside a unit and its two significant subdivisions.

The vernier scale is most commonly found on length measuring instruments including vernier callipers, screw gauges, and micrometres.

vernier scale diagram

Scale of chords-

In the case of lack of a protractor, a chord scale can be used to determine or establish the required angle. The structure is based on chord lengths of angles measured over an identical arc.

scale of chords diagram

Wrapping Up-

This concludes the types of scales in engineering drawing for the time being. I hope this has been of use to you or has provided you with some value. If that’s the case, consider sharing Engineers Rail with others in need and bookmarking it for future reference.

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Thank you for taking the time to pay attention to me. I’m looking forward to seeing you in the next segment.

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