Projection · Sketching · Views · Title blocks · Line types
Q1Types of Engineering Drawing
2 marks✓▼
Question
Engineering drawings can be produced using different methods of projection. State the TWO main types of orthographic projection used in engineering.
2 marks — 1 mark each
✓ First angle projection (also known as European projection)
✓ Third angle projection (also known as American projection)
💡 How to tell them apart: First angle — the view you see is placed on the opposite side. Third angle — the view is placed on the same side you're looking from. Third angle is most common in the UK engineering industry today.
Q2Freehand Sketching
2 marks✓▼
Question
A design engineer produces a freehand sketch when meeting with a client. Explain what is meant by a freehand sketch and state ONE advantage of using one at this stage.
2 marks
What is a freehand sketch
✓ A drawing produced by hand without the use of drawing instruments, CAD software or templates — drawn quickly to communicate an initial idea or concept
One advantage
✓ Quick and easy to produce — ideas can be communicated and modified on the spot without specialist equipment
✓ No equipment is needed — can be done anywhere during a meeting or discussion
💡 Key point: Freehand = no instruments. It is used for early-stage ideas and communication, NOT for manufacturing. Manufacturing requires formal dimensioned drawings.
Q3Exploded View Drawings
2 marks✓▼
Question
A technician is assembling a complex component for the first time and is given an exploded view drawing. Explain the purpose of an exploded view drawing and state who typically uses them.
2 marks
✓ An exploded view drawing shows all the individual parts of an assembly separated out along their assembly axes, so the relationship between each component and the assembly sequence can be clearly understood
✓ They are used by assembly technicians, maintenance engineers, and in instruction manuals — to show how a product is put together or taken apart
💡 Think of: IKEA instruction diagrams — they show each part separately so you know what order to assemble them. That is an exploded view.
Q4Title Block Information
3 marks✓▼
Question
Every engineering drawing contains a title block. The title block always includes the name of the part or assembly being drawn. State THREE other items of information that would typically be found in the title block of an engineering drawing.
3 marks — 1 mark each
Any 3 of the following
✓ Drawing number / part number
✓ Scale of the drawing
✓ Material the part is made from
✓ Date the drawing was created or last revised
✓ Name or initials of the draughtsperson / designer
✓ Projection method used (first or third angle symbol)
✓ Units used (e.g. mm)
✓ Revision number / issue number
✓ Company name or logo
✓ Sheet size (e.g. A3, A4)
💡 Tip: Learn at least 5 so you always have spare options in the exam. The question only needs 3 but having extras gives you choice.
Q5Line Types on Engineering Drawings
1 mark✓▼
Question
The drawing below shows a line type used on engineering drawings.
— — — — — —
Identify this line type and state what it is used to represent on an engineering drawing.
1 mark
✓ This is a hidden detail line (dashed line) — it is used to show edges or features that exist behind or inside the component and cannot be seen from the current viewing direction
Line type
Appearance
Used for
Continuous thick
——————
Visible outlines and edges
Continuous thin
——————
Dimension lines, projection lines, hatching
Dashed
– – – – –
Hidden detail (features not visible)
Chain (long dash dot)
–·–·–·–
Centre lines, axes of symmetry
Chain (long dash double dot)
–··–··–
Adjacent parts / outlines of alternative positions
Q6Tolerance
2 marks✓▼
Question
A shaft is dimensioned on an engineering drawing as 50 ±0.05 mm. Describe what is meant by the term 'tolerance' in this context, and calculate the upper and lower limit sizes for this shaft.
2 marks
✓ Tolerance is the total permissible variation in a dimension — the difference between the maximum and minimum acceptable size of a feature
✓ Upper limit = 50.05 mm · Lower limit = 49.95 mm · Total tolerance = 0.10 mm
💡 Formula: Upper limit = nominal + tolerance. Lower limit = nominal − tolerance. Total tolerance = upper − lower. Tighter tolerances = more expensive to manufacture.
02
Engineering Symbols
Mechanical symbols · GDT symbols · Surface finish
Q7Mechanical Drawing Symbols
4 marks✓▼
Question
Complete the table by stating the meaning of each mechanical symbol commonly used on engineering drawings.
4 marks — 1 mark per symbol
Symbol
Meaning
Diameter symbol — indicates the measurement shown is a diameter (of a circle or cylindrical feature)
Surface texture / roughness symbol — indicates a machined surface finish is required on that face
Surface must not be machined / material removal not permitted — the surface is left in its original as-cast or as-rolled condition
Square / rectangular cross-section — indicates the feature shown has a square cross-section (used instead of writing SQ)
💡 Tip: Surface finish symbols always sit on the line representing the surface they refer to. The tick with a bar = machined. Tick with circle = any process. Tick with added horizontal = no machining.
A company is considering switching from manual drawing boards to Computer Aided Design (CAD) software.
a) Explain TWO benefits of producing engineering drawings using CAD instead of manually. (4 marks)
b) State ONE limitation of using CAD compared to producing drawings manually. (2 marks)
6 marks total
Part a — 2 benefits (2 marks each: 1 for what, 1 for why/how)
✓Drawings can be edited quickly and easily — changes can be made to any part of the drawing without starting again, saving time and reducing errors compared to erasing and redrawing manually
✓High accuracy and consistency — CAD produces geometrically perfect lines, arcs and dimensions every time; manual drawing is subject to human error and imprecision
✓Drawings can be shared instantly and stored electronically — files can be emailed, archived and accessed from multiple locations; no risk of physical drawings being lost or damaged
✓Libraries of standard components and symbols — existing parts can be inserted from a library without redrawing, significantly speeding up the drawing process
✓CAD data can be used directly by CNC machines or for simulation — the drawing data can feed into manufacturing or be used to test a design virtually before making it
Part b — 1 limitation (2 marks: 1 for what, 1 for why it is a limitation)
✓High initial cost — CAD software licences and the hardware needed to run it can be very expensive, which may be prohibitive for small companies
✓Training is required — staff need significant time and training to become proficient with CAD software; there is a learning curve that reduces productivity initially
✓System failures / data loss risk — if the computer or software crashes, work can be lost unless regularly backed up; this is not a risk with paper drawings
In engineering, 'quality' does not simply mean expensive or luxurious. Give a precise definition of what 'quality' means in an engineering context.
1 mark
✓ Quality means that a product or service meets or conforms to its specified requirements / is fit for its intended purpose
💡 Key phrase: "Fitness for purpose" or "conformance to specification" — a quality product does exactly what it is supposed to do, to the standard it was designed to.
Q11Quality Control vs Quality Assurance
2 marks✓▼
Question
Explain the difference between quality control (QC) and quality assurance (QA) in an engineering business. Give ONE example of each.
2 marks
✓Quality control (QC) — the inspection and testing of finished or in-progress products to detect defects before they reach the customer (reactive). Example: measuring the diameter of a machined shaft with a micrometer to check it is within tolerance
✓Quality assurance (QA) — the systems, procedures and processes put in place to prevent defects from occurring in the first place (proactive). Example: writing and following a documented work instruction that specifies the correct machining parameters to use
💡 Memory aid: QC = catch it. QA = prevent it. QC is checking the output; QA is managing the process that creates the output.
Q12Product Specification
3 marks✓▼
Question
Before a product is designed and manufactured, a product specification is produced. Explain the purpose of a product specification and state TWO types of information it typically contains.
3 marks
Purpose (1 mark)
✓ A product specification defines all the requirements a product must meet — it sets out what the product must do, how it must perform, and the standards it must conform to, so that it can be designed, manufactured and tested against agreed criteria
Types of information — any 2 (1 mark each)
✓ Dimensional requirements — sizes, tolerances and fits
✓ Material requirements — what material the product must be made from and any required properties (e.g. hardness, conductivity)
✓ Performance requirements — what the product must do (e.g. load capacity, operating temperature range)
✓ Surface finish requirements — the required surface roughness or coating
✓ Applicable standards or regulations (e.g. BS, ISO, CE marking requirements)
Q13Quality Assurance Documentation
2 marks✓▼
Question
State TWO different types of documentation that are used as part of a quality assurance system in an engineering business.
2 marks — 1 mark each
Any 2 of the following
✓ Work instructions / standard operating procedures (SOPs)
✓ Inspection records / inspection reports
✓ Control plans
✓ Non-conformance reports (NCRs)
✓ Calibration records for measuring equipment
✓ Quality plans
✓ Test certificates / material certificates
Q14Objective vs Subjective Assessment
4 marks✓▼
Question
When assessing the quality of engineering products, inspectors may use objective or subjective methods. Explain the difference between objective and subjective assessment, and give ONE engineering example of each.
4 marks — 2 marks per type (explanation + example)
Objective assessment (2 marks)
✓ Objective assessment involves measuring or testing against a definite, numerical standard that does not depend on personal judgement — the result is pass or fail based on measurable data
✓ Example: measuring the diameter of a shaft with a micrometer and comparing it to the drawing tolerance — 50.02 mm is either within or outside the specified 50 ±0.05 mm limit
Subjective assessment (2 marks)
✓ Subjective assessment relies on the personal judgement or opinion of the inspector — there is no fixed numerical value; different people may reach different conclusions
✓ Example: visually inspecting a painted surface for an acceptable finish — whether a slight colour variation is acceptable may differ between inspectors
💡 Simple rule: Objective = you can measure it with an instrument and get a number. Subjective = someone has to look at it and use their judgement. Engineering prefers objective wherever possible.
Q15Statistical Process Control (SPC)
2 marks✓▼
Question
Explain what is meant by Statistical Process Control (SPC) and state ONE benefit of using it in a manufacturing environment.
2 marks
What SPC is (1 mark)
✓ Statistical Process Control (SPC) is a method of monitoring and controlling a manufacturing process by collecting data (measurements) from samples during production and plotting them on control charts — this allows trends or variations to be identified before defects occur
One benefit (1 mark)
✓ Problems or trends in the process can be identified and corrected early, before out-of-tolerance parts are produced — reducing scrap and rework
✓ Provides objective evidence that the process is in control and capable of consistently meeting the required specification
💡 Key idea: SPC is proactive — it monitors the process while it is running rather than inspecting finished parts. Control charts have upper and lower control limits; if data points drift toward these limits, action is taken before parts go out of tolerance.