Technical Apprnetice Flashcards
- What is the difference between a bolt and a screw?
Tip: They test basic mechanical knowledge.
Sample Answer:
A bolt usually passes through a pre-drilled hole and is secured with a nut, providing clamping force.
A screw, on the other hand, is designed to cut its own thread into the material it’s fastening.
- What are the three types of stress a material might experience?
Sample Answer:
Tensile (pulling apart),
compressive (pushing together),
shear (sliding layers).
Understanding these is important in mechanical design to prevent failure.
- What is tolerance, and why is it important in engineering?
Sample Answer:
Tolerance is the allowed variation in a dimension. It ensures that parts fit together properly and perform as designed, even with small manufacturing differences.
- Explain what a lathe does.
Sample Answer:
A lathe is a machine tool that rotates a workpiece while a cutting tool shapes it. It’s used for making cylindrical parts, cutting threads, or drilling holes.
- Name a material you might use for a lightweight but strong component and explain why.
Sample Answer:
Aluminum is often used because it’s lightweight, corrosion-resistant, and has a good strength-to-weight ratio—ideal for aerospace parts.
- What is a bearing, and what does it do?
Sample Answer:
A bearing reduces friction between moving parts and supports rotational or linear movement. Common in engines, shafts, and wheels.
- How would you measure a component accurately?
- How would you measure a component accurately?
Sample Answer:
To measure a component accurately, I would first make sure the component is clean and free from any debris or burrs. Depending on the measurement needed, I would select the right tool—like a vernier caliper, micrometer, or gauge block—for the required precision. I’d double-check my readings, ensure the tool is calibrated, and repeat the measurement to confirm accuracy. This helps make sure the component meets the required tolerance.
- What is the purpose of a micrometer or vernier caliper?
Sample Answer:
Both tools are used for precise measurements, but they serve slightly different purposes. A vernier caliper is versatile and can measure inside, outside, and depth dimensions of a component with good accuracy.
A micrometer, on the other hand, is used when you need very precise measurements—typically to within one-thousandth of a millimeter—on small components like shafts or thin materials. Both are essential in mechanical engineering to ensure parts fit and work properly.
- What is meant by “preventive maintenance”?
Preventive maintenance means carrying out regular checks, servicing, and replacing parts before a machine or tool breaks down. It helps keep equipment running safely and efficiently, reduces the risk of unexpected failures, and extends the life of machines. For example, regularly oiling moving parts or inspecting belts for wear would be preventive maintenance tasks in a workshop.
- Can you describe a time you worked with hand tools or machinery?
Sample Answer:
During my college course, I worked in the workshop using both hand tools and machines. One example was when I used a lathe to machine a metal shaft to specific dimensions. I measured it with a micrometer after each pass to ensure accuracy. I also used hand tools like files and deburring tools to finish the edges. I followed all safety procedures, wore the correct PPE, and completed the part to the drawing specification. It gave me good hands-on experience with both manual skills and precision measurement.
What is the strongest to weakest metal?
- Titanium (Strongest & lightest combo but costly—rarely used except on subs/high-tech vessels)
- High-Strength Steel (Main strength material for large hulls and military vessels)
- Stainless Steel (Strong, corrosion-resistant, used for critical fittings)
- Aluminum Alloys (Strong relative to weight, excellent for fast/light vessels)
- Copper-Nickel Alloys (CuNi) (Moderate strength, very good corrosion resistance)
- Bronze (Stronger than brass, good for propellers and underwater parts)
- Brass (Softer than bronze, corrosion-resistant but less structural strength)
- Lead (Weak, soft—used purely as ballast for weight)
- What is a bearing, and what does it do?
A bearing reduces friction between moving parts and supports rotational or linear movement.
Common in engines, shafts, and wheels.
- What is the purpose of a gearbox?
A gearbox changes the speed and torque of power from a motor or engine. It lets machines run efficiently at different speeds and loads.
- Explain the difference between tensile and compressive forces.
- Explain the difference between tensile and compressive forces.
Tensile forces pull materials apart, while compressive forces push them together. Both need to be considered in mechanical design to avoid failure.
- What is a CAD drawing, and why is it important?
CAD stands for Computer-Aided Design. It’s used to create accurate technical drawings and models of parts. It helps spot design problems early and ensures manufacturers know exactly what to make.
- How do you ensure accuracy when measuring a component?
- How do you ensure accuracy when measuring a component?
I use precise tools like calipers or micrometers, double-check my readings, and make sure the part is clean. Accurate measurements ensure parts fit and function correctly.
- Name some common workshop tools and explain their uses.
Lathe – for turning round parts;
Milling machine – for shaping surfaces;
Vernier caliper – for measuring internal/external dimensions;
Hand files – for smoothing edges.
- What is the function of a bearing?
- What is the function of a bearing?
Bearings support rotating parts like shafts and reduce friction. They’re found in engines, wheels, and many machines.
- What is meant by tolerance and fit?
- What is meant by tolerance and fit?
Tolerance is the allowed variation in a part’s size. Fit is how two parts fit together—tight, loose, or somewhere in between. Both are important for assembly and function.
- What safety checks would you perform before using machinery?
- What safety checks would you perform before using machinery?
Check the machine guards are in place, ensure no damage or loose parts, make sure emergency stops work, and confirm I’m wearing the correct PPE.
- What is thermal expansion, and how does it affect parts?
- What is thermal expansion, and how does it affect parts?
When materials heat up, they expand. This can cause parts to jam or fail if not accounted for, especially in engines or aircraft exposed to heat.
- Why is material selection important?
- Why is material selection important?
Different materials have different strengths, weights, and costs. Choosing the right one is vital to make sure parts work properly, safely, and efficiently.
- Explain how a hydraulic system works.
- Explain how a hydraulic system works.
A hydraulic system uses fluid pressure to move or lift heavy loads. It works because fluids don’t compress, allowing force to transfer efficiently.
- What are the advantages of aluminum in aircraft production?
- What are the advantages of aluminum in aircraft production?
Aluminum is light, strong, and resists corrosion, making it ideal for reducing aircraft weight while keeping strength high.
- What is preventive maintenance, and why is it important?
- What is preventive maintenance, and why is it important?
It’s regular maintenance done to prevent breakdowns. In engineering, it keeps machines safe, reliable, and extends their life.
- Explain what is meant by shear stress.
- Explain what is meant by shear stress.
Shear stress happens when forces cause layers of material to slide past each other, like cutting paper with scissors.
- How does a micrometer work, and what is it used for?
- How does a micrometer work, and what is it used for?
A micrometer is a precise measuring tool. It uses a calibrated screw to measure thickness or diameter to a very high degree of accuracy, often in millimeters or microns.
What is a Gauge Block?
What is a Gauge Block?
Gauge blocks, also known as slip gauges or Jo blocks, are precision-ground metal or ceramic blocks used to measure and calibrate dimensions very accurately in mechanical engineering and fitting.
They are manufactured to extremely tight tolerances and come in sets of different thicknesses.
Why are Gauge Blocks Used?
Why are Gauge Blocks Used?
• To calibrate measuring tools like micrometers, vernier calipers, and dial gauges
• For setting up machine tools to specific heights or dimensions
• For measuring components where extreme precision is required
• To check tolerances in parts during inspection
How Do They Work? (“Wringing” Gauge Blocks)
How Do They Work? (“Wringing” Gauge Blocks)
• Gauge blocks are used by “wringing” them together—lightly sliding two blocks until they stick due to molecular attraction and air pressure.
• This creates a precise stack of known measurements.
• They provide a reference standard when measuring or calibrating.
