MCQ on Drilling Machine with Answers & Explanations

1. What is the primary function of a drilling machine in manufacturing? 

a) Boring holes 

b) Cutting metal 

c) Shaping surfaces 

d) Forming threads 

Answer: a) Boring holes 

Explanation: Drilling machines are primarily used for boring holes in various materials such as metal, wood, and plastic. This process involves rotating a cutting tool (drill bit) to create cylindrical holes.

2. Which of the following types of drilling machine is suitable for heavy-duty industrial applications? 

a) Bench drill 

b) Radial drill 

c) Hand drill 

d) Pillar drill 

Answer: b) Radial drill 

Explanation: Radial drills are designed for heavy-duty industrial applications where large and heavy workpieces need to be drilled. They offer flexibility in positioning the drill head and arm.

3. In a twist drill bit, the angle between the cutting edge and the axis of the bit is known as: 

a) Helix angle 

b) Point angle 

c) Flute angle 

d) Lip angle 

Answer: d) Lip angle 

Explanation: The angle between the cutting edge and the axis of the twist drill bit is known as the lip angle. It affects the cutting action and chip formation during drilling.

4. Which of the following materials is commonly used for manufacturing twist drill bits? 

a) Aluminum 

b) Brass 

c) High-speed steel (HSS) 

d) PVC 

Answer: c) High-speed steel (HSS) 

Explanation: High-speed steel (HSS) is a common material used for manufacturing twist drill bits due to its hardness, wear resistance, and ability to withstand high temperatures generated during drilling.

5. Which of the following drilling operations is used to create a flatbottomed hole? 

a) Counterboring 

b) Spot drilling 

c) Tapping 

d) Countersinking 

Answer: a) Counterboring 

Explanation: Counterboring is the process of enlarging the opening of a hole on one side to create a flat-bottomed recess, often used to accommodate the head of a bolt or screw.

6. What is the purpose of a centre drill in drilling operations? 

a) To create a starter hole 

b) To enlarge an existing hole 

c) To create threads 

d) To deburr holes 

Answer: a) To create a starter hole 

Explanation: Centre drills are used to create a small starter hole or indentation at the centre of the workpiece to guide the larger drill bit during drilling.

7. Which of the following factors does NOT affect the drilling speed? 

a) Feed rate 

b) Workpiece material 

c) Drill bit material 

d) Ambient temperature 

Answer: d) Ambient temperature 

Explanation: Ambient temperature generally does not directly affect drilling speed. Factors such as drill bit material, workpiece material, and feed rate significantly influence drilling speed.

8. The term "chatter" in drilling refers to: 

a) Smooth cutting action 

b) Vibration during drilling 

c) Accurate hole alignment 

d) High-speed drilling 

Answer: b) Vibration during drilling 

Explanation: Chatter in drilling refers to the undesirable vibration or oscillation of the drill bit during the drilling process, which can result in poor surface finish and accuracy.

9. The process of drilling multiple holes simultaneously is known as: 

a) Gang drilling 

b) Step drilling 

c) Jig drilling 

d) Index drilling 

Answer: a) Gang drilling 

Explanation: Gang drilling involves drilling multiple holes simultaneously in a workpiece using multiple drill bits mounted on a common drilling machine or fixture.

10. What is the function of a pilot hole in drilling operations? 

a) To guide the drill bit 

b) To enlarge the hole 

c) To remove burrs 

d) To secure the workpiece 

Answer: a) To guide the drill bit 

Explanation: A pilot hole is a small-diameter hole drilled before the main drilling operation to guide the larger drill bit accurately and prevent it from wandering off course.

11. Which of the following drilling methods is suitable for producing very precise and accurate holes? 

a) CNC drilling 

b) Manual drilling 

c) Power drilling 

d) Pneumatic drilling 

Answer: a) CNC drilling 

Explanation: CNC (Computer Numerical Control) drilling utilizes computer-controlled machines to precisely position and operate the drill bit, ensuring accuracy and repeatability in hole dimensions.

12. Which of the following drill press components is responsible for controlling the drilling depth? 

a) Chuck 

b) Spindle 

c) Depth stop 

d) Table 

Answer: c) Depth stop 

Explanation: The depth stop on a drill press allows the user to set a specific drilling depth, ensuring consistent hole depths across multiple workpieces.

13. The process of enlarging the opening of a hole to accommodate a screw head is called: 

a) Countersinking 

b) Reaming 

c) Tapping 

d) Counterboring 

Answer: a) Countersinking 

Explanation: Countersinking is the process of enlarging the opening of a hole at the surface to accommodate the head of a screw, bolt, or fastener, allowing it to sit flush with or below the surface.

14. Which of the following drilling methods is commonly used for creating holes in printed circuit boards (PCBs)? 

a) CNC drilling 

b) Laser drilling 

c) Water jet drilling 

d) Ultrasonic drilling 

Answer: b) Laser drilling 

Explanation: Laser drilling is a precise and efficient method commonly used for creating small-diameter holes in printed circuit boards (PCBs) with high accuracy and minimal heat-affected zones.

15. What safety equipment should be worn when operating a drilling machine? 

a) Safety goggles 

b) Welding helmet 

c) Earplugs 

d) Gloves 

Answer: a) Safety goggles 

Explanation: Safety goggles protect the eyes from flying debris, metal chips, and other hazards generated during drilling operations.

16. Which of the following drill bits is specifically designed for drilling in masonry and concrete? 

a) Brad point 

b) Twist drill 

c) Masonry bit 

d) Spade bit 

Answer: c) Masonry bit 

Explanation: Masonry bits are designed with a carbide tip and fluted shank to effectively drill into hard materials such as concrete, brick, and stone.

17. The process of tapping involves: 

a) Enlarging an existing hole 

b) Creating internal threads 

c) Removing burrs from holes 

d) Countersinking holes 

Answer: b) Creating internal threads 

Explanation: Tapping is the process of cutting internal threads into a drilled hole using a tap, which matches the desired thread size and pitch.

18. Which of the following drill bit coatings improves heat resistance and prolongs tool life? 

a) Titanium nitride (TiN) 

b) Aluminum oxide (Al2O3) 

c) Tungsten carbide (WC) 

d) High-speed steel (HSS) 

Answer: a) Titanium nitride (TiN) 

Explanation: Titanium nitride (TiN) coating provides enhanced wear resistance and heat resistance to drill bits, prolonging tool life and improving performance in high-temperature drilling applications.

19. What is the purpose of the drill press table in drilling operations? 

a) To support the workpiece 

b) To secure the drill bit 

c) To adjust the drilling depth 

d) To control the spindle speed 

Answer: a) To support the workpiece 

Explanation: The drill press table provides a stable surface to support the workpiece during drilling operations, ensuring accurate hole placement and preventing workpiece movement.

20. The process of drilling a hole at an angle to the workpiece surface is called: 

a) Counterboring 

b) Spot drilling 

c) Chamfering 

d) Angular drilling 

Answer: d) Angular drilling 

Explanation: Angular drilling involves drilling holes at an angle other than perpendicular to the workpiece surface, often used for creating chamfers or countersinks.

21. Which of the following factors affects the accuracy of drilled holes? 

a) Drill bit size 

b) Feed pressure 

c) Spindle speed 

d) All of the above 

Answer: d) All of the above 

Explanation: Factors such as drill bit size, feed pressure, and spindle speed can all affect the accuracy of drilled holes by influencing hole diameter, surface finish, and hole location.

22. What is the purpose of a drill jig in manufacturing? 

a) To hold the workpiece securely 

b) To guide the drill bit accurately 

c) To adjust the spindle speed 

d) To lubricate the cutting tool 

Answer: b) To guide the drill bit accurately 

Explanation: A drill jig is a device used to hold the workpiece securely and guide the drill bit accurately during drilling operations, ensuring precise hole placement and alignment.

23. Which of the following drilling methods is suitable for creating holes in glass and ceramics? 

a) Diamond drilling 

b) CNC drilling 

c) Hammer drilling 

d) Ultrasonic drilling 

Answer: a) Diamond drilling 

Explanation: Diamond drilling utilizes diamond-tipped drill bits to create precise holes in hard and brittle materials such as glass, ceramics, and composites.

24. The process of enlarging the opening of a hole on one side to accommodate the head of a bolt is called: 

a) Counterboring 

b) Countersinking 

c) Spot facing 

d) Reaming 

Answer: a) Counterboring 

Explanation: Counterboring involves enlarging the opening of a hole on one side to create a flat-bottomed recess, typically used to accommodate the head of a bolt or screw.

25. Which of the following drill bit materials is NOT suitable for drilling hardened steel? 

a) Cobalt steel 

b) Carbide 

c) High-speed steel (HSS) 

d) Titanium nitride (TiN) coated steel 

Answer: d) Titanium nitride (TiN) coated steel 

Explanation: While titanium nitride (TiN) coating improves the wear resistance of drill bits, it is not specifically designed for drilling hardened steel. Materials such as cobalt steel and carbide are more suitable for drilling hardened steel due to their hardness and heat resistance.