Work through these eight original questions in order, writing your working before you open each answer. They cover the three lessons in drawing conventions and scale.
Questions
1. A view shows a dashed rectangle inside a thick rectangle. What does the dashed rectangle represent?
Answer
A feature that exists but is hidden from the viewing direction, such as a slot or a pocket behind the front face. It is not a faint visible edge.
2. A thin line with two arrowheads and the figure 64 lies under a front view. The drawn line measures 5 cm on your screen. What is the size of the part, and why?
Answer
The size is 64 mm, taken from the figure. The screen length depends on the device and cannot be used as a measurement.
3. A long-short-long thin line passes through the middle of a circle. Name the line and say what it marks.
Answer
It is a centre line (thin chain line). It marks the centre or axis of the circle, which here is a hole or a round part.
4. A plate has a chain of dimensions 22, z, 31, 15 and an overall length of 100. Find z.
Answer
22 + z + 31 + 15 = 100, so z = 100 − 22 − 31 − 15 = 32. Check: 22 + 32 + 31 + 15 = 100.
5. A drawing is at scale 1:5. A line measures 18 mm on the sheet. What is the real length?
Answer
1:5 is a reduction, so real length is larger: 18 × 5 = 90 mm.
6. A rivet has real length 8 mm and is drawn at 10:1. What length should be drawn?
Answer
10:1 is an enlargement, so the drawn line is longer: 8 × 10 = 80 mm.
7. Two drawings of the same part are given. Drawing A is at 1:2 and a slot measures 20 mm on it.
Drawing B is at 1:5. How long should the same slot be on Drawing B?
Answer
Real slot length = 20 × 2 = 40 mm. On Drawing B: 40 ÷ 5 = 8 mm.
Sense check: Drawing B is smaller than A, so the drawn slot should be shorter than 20 mm. It is.
8. A student says the bottom line is thick, so it must be a dimension line. Give two reasons they are wrong.
Answer
Dimension lines are thin, not thick, and they have arrowheads and a figure. A thick continuous line is a visible outline of the object.
If you got these wrong
- Questions 1, 3 and 8: reread interpreting line types.
- Questions 2 and 4: reread reading dimensions without measuring the screen.
- Questions 5, 6 and 7: reread converting between stated scales.
Next, read how lines and sizes work across several views in orthographic views.
If you want a teacher to set fresh questions and check your working, see online one-to-one Engineering Drawing tuition.