Technical Interview Questions for Fresher Mechanical Design Engineers

One shall carefully read job description before every interview. Always ask yourself, What skill-sets they are looking for. For example, for gear manufacturer company, revise your knowledge about gears. In this article, we will discuss commonly asked mechanical Design interview questions and answers. 

What are engineering tolerance?

Engineering Tolerance is allowable variation from given dimension. In another words, it is the total amount by which a given dimension may vary without affecting product function.

Tolerance (for hole) = Hole (MMC) – Hole (LMC)

Why Tolerance are Required? 

The production of closely mating parts, without tolerances is economically unfeasible. This results in increase in rejection rate. This will also increase overall product cost. This is the reason, we use tolerance in part dimensions.

Check out in detail about tolerance here

What do you understand by fit?

The term fit refers to the permissible clearances between mating parts. In another words,  “Engineering Fit” is the clearance between two mating parts. This clearance determines the type of Fit. check out in detail about fit here

What are the different types of fits?

  1. Clearance Fit
  2. Interference Fit
  3. Transition Fit

What are the types of tolerance?

  1. Unilateral Tolerance
  2. Bilateral Tolerance

What do you understand you Engineering Drawing?

Engineering drawing is a technical document used to transfer technical information and define requirements. In other words, its a graphical language that communicates ideas and information from one mind to another.

What is Section, Projection, Isometric & Detailed View?

  • Projection View : Projection view represents a 3 dimensional objects in 2 dimensions.
  • Section View: Sections view shows the interior construction of a part in engineering drawing.
  • Isometric View: Isometric projection represents a 3D objects into 2D in a technical and engineering drawings. In isometric view three coordinate axes appear equally foreshortened and the angle between any two of them is 120 degrees.
  • Detailed View: Detailed view represents the larger view of any section in engineering drawing.

What is the symbol of 1st and 3rd angle projection?

First Angle Projection

Third Angle Projection

What are types of projections used to make engineering drawings?

Following two types of projections are used :

What is least count and how it is calculated?

Least count is the smallest value measured with the measuring instrument. For example, least count of a normal scale is 1mm and vernier scale is 0.01 mm. 

Least Count= Value of one main scale Division – Total Number of Vernier scale division

What is least count for Vernier Scale, Micrometer and normal scale?

  • Least Count for vernier = 0.01 mm (Digital) , 0.02 mm (manual)
  • Least Count for micrometer = 0.01 mm
  • Least count of normal scale = 1 mm 

What is factor of safety and how it is calculated?

FOS describes the load carrying capacity of a system beyond the expected or actual loads. In another words, FOS represents : how much stronger the system is compared to intended load.

FOS is calculated considering design load maximum value. Value of FOS is always greater than one.

What are types of screws?

Screws can be classified based on following parameters:

Based on Screw Head

  1. Counter Sunk Screw
  2. Raised or oval head screw
  3. Pan Head Screw
  4. Flat Head Screw
  5. Flange Head Screw

Based on Screw Drive Type

  1. Sloted
  2. Phillip 
  3. Pozi Drive
  4. Torx Head
  5. Hex Socket
  6. Trangular head
  7. Security Head Socket

Based on Screw Thread Type

  1. Machine Screw
  2. Thread Forming
  3. Thread Cutting Screw

What is datum plane?

A datum is theoretical exact plane, axis or point location that GD&T or dimensional tolerances are referenced to.

What is GD&T?

Geometric Dimension & Tolerance (GD&T) is a system for defining engineering tolerances. GD&T is very important part of mechanical product design.

GD&T defines degree of accuracy and precision required on controlled feature of part, allowable variation in form and possible size.

Check out the basics of gd&t here


What is Section, Break and centre line?

What is difference between 1st and 3rd angle projection?

What is difference between Size dimension & Location dimension?

What are ordinate dimensions?

What are different surface finish symbols?

What are different welding symbols?

What are various manufacturing process?

What are commonly used machining operations?

What do you understand by Sheet Metal?

What is injection moulding?

Where you did your industrial training? In which department you worked?

Firstly tell them list of industrial training you did and what you learned there.

They will try to find out knowledge gained from training. 

What was your Final Year Project and what you learned from that?

Start with aim of the project, followed by what you learned in your project.

Interviewer may ask you technical questions about your Project.


To sum up, in this article we discussed the questions that are not specific to any industry. Everyone planning for interview should know the basics of mechanical design. 

Got Question?  We will be happy to help.

If you think we missed Something?  You can add to this article by sending message in comment box. We will do our best to add it in this post.

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