CXC CSEC Technical Drawing — Paper 2 (Geometrical and Building/Mechanical Drawing)

Total marks: 90 · Duration: 150 minutes

Instructions to candidates

Answer ALL questions in Section A (Geometrical Construction) and the questions for your chosen option in Section B: EITHER Building Drawing OR Mechanical Engineering Drawing.
All construction lines must be clearly shown.
Work neatly; marks are awarded for accuracy, correct method and presentation.
Drawing instruments are required.

Paper

Section A — Geometrical Construction (40 marks)

1. (a) Construct a regular hexagon with sides of 40 mm. Show all construction lines. (6 marks) (b) State the size of each interior angle of a regular hexagon and show how it is calculated. (2 marks)

2. (a) Construct a tangent to a circle of radius 30 mm from a point P located 70 mm from the centre. (6 marks) (b) State the relationship between a tangent and the radius at the point of contact. (2 marks)

3. A solid rectangular block measures 60 mm × 40 mm × 30 mm. (a) Draw the front elevation, end elevation and plan in first-angle orthographic projection. (9 marks) (b) State which projection symbol you would place in the title block. (1 mark)

4. Draw an isometric view of a cube of side 40 mm, showing the isometric axes. (6 marks)

5. Produce the development of the curved surface of a cylinder of diameter 35 mm and height 50 mm. State the length of the development. (6 marks) (Take π = 3.14)

Section B — Option 1: Building Drawing (50 marks)

6. Figure 1 shows the outline of a small single-room building, 5 m × 4 m, with one door (0.9 m) and one window (1.2 m). (a) Draw the floor plan to a scale of 1:50, showing the walls (200 mm thick), the door (with swing) and the window. (20 marks) (b) Draw the front elevation of the building, wall height 2.7 m, with a pitched roof. (15 marks) (c) Add a north point, a title and the scale to your drawing. (5 marks) (d) Label the door and window and give the internal room dimensions. (10 marks)

Section B — Option 2: Mechanical Engineering Drawing (50 marks)

7. Figure 2 shows two views of a machined bracket. (a) Draw a full sectional front view on the cutting plane A–A, hatching the cut surfaces correctly. (20 marks) (b) Fully dimension your drawing, using the correct symbols for diameters and radii. (15 marks) (c) State two conventions you applied (e.g. shafts/ribs not hatched; hatching at 45°). (5 marks) (d) Add a suitable title block including the scale and projection symbol. (10 marks)

Mark Scheme (key points)

1 (a) circle of radius = side; step off the radius six times / use 60° set square (construction shown) (up to 6). (b) (6−2)×180÷6 = 120° (2). 2 (a) correct construction (e.g. semicircle on the line from P to centre; tangent through intersection) with lines shown (6). (b) the tangent is perpendicular to the radius at the point of contact (2). 3 (a) three correctly aligned and proportioned views in first-angle projection (9). (b) the truncated-cone first-angle symbol (1). 4 correct isometric cube with vertical edges and 30° receding lines (6). 5 rectangle of height 50 mm and length = πd = 3.14 × 35 = 109.9 ≈ 110 mm (6).

Building option (6): accurate plan to 1:50 with walls/door/window (20); correct front elevation with roof (15); north point, title, scale (5); labelling and dimensions (10). Credit accuracy, correct conventions and neat presentation.

Mechanical option (7): correct full section with proper hatching (20); complete and correct dimensioning (15); two valid conventions stated (5); proper title block with scale and symbol (10).

Sample Answers with Examiner Commentary

Question 1(b) — Sample Answers

Grade I (Distinction) answer "A hexagon has 6 sides, so the sum of the interior angles is (6 − 2) × 180° = 720°. Since it is regular, each interior angle is 720° ÷ 6 = 120°." Mark: 2/2. Examiner commentary: The candidate states the formula, the working and the correct result — full marks.

Grade III (Pass) answer "Each angle is 120°." Mark: 1/2. Examiner commentary: The correct value is given but no working is shown, so only the result mark is awarded. Candidates should always show the calculation (n − 2) × 180 ÷ n.

Question 5 — Sample Answers

Grade I answer "The development is a rectangle. Its height equals the cylinder height (50 mm) and its length equals the circumference, πd = 3.14 × 35 = 109.9 mm, so length ≈ 110 mm." Mark: 6/6. Examiner commentary: Correctly identifies the development as a rectangle and computes the length from the circumference. Top band.