T1-L11: Technical Lettering & Scale

Name:

Class:

Date:

Folio: pp. 48–55

Outcomes: TE4-DES-01 TE4-PPM-01 Folio pp. 48–55

Learning Intention

We are learning technical lettering and how to use scale in engineering drawings.

Success Criteria

I can write neat, consistent technical letters
I can explain what scale means (e.g. 1:2, 1:10)
I can calculate scaled dimensions
I can apply scaling to simple objects

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Do Now

If a model is 1:10 scale and the model is 5 cm long, how big is the real object?

Your working	Answer	How did you work it out?

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Key Vocabulary

Standard: Fill in the definition. | Support: Definitions shown in grey — read and copy into your folio. | Extension: Use each term in a sentence.

Term	Definition	Use in a sentence (Extension)
Scale	A ratio between the size of a drawing/model and the real object
Ratio	A comparison between two quantities, written as a:b
Proportion	The relationship between parts — keeping everything in the correct relative size
Enlarge	To make a drawing BIGGER than the real object (e.g. 2:1)
Reduce	To make a drawing SMALLER than the real object (e.g. 1:10)
Technical lettering	A neat, standardised way of writing letters on engineering drawings

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Technical Lettering Rules

Technical lettering ensures engineering drawings are clear and readable for everyone.

#	Rule	Why it matters
1	Always use UPPERCASE letters
2	Keep all letters the same height
3	Space letters evenly
4	Letters are vertical (straight up)
5	Use sans-serif style

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Scale Calculations (Folio pp. 52–55)

Model → Real (finding real size)

Real = Model × Scale factor

e.g. 5 cm at 1:10 → 5 × 10 = 50 cm

Real → Model (finding model size)

Model = Real ÷ Scale factor

e.g. 3 m at 1:20 → 300 cm ÷ 20 = 15 cm

Practice Problems: Show all working. Convert to cm first!

#	Problem	Your working and answer
1	A table is 1.5 m long. At 1:10 scale, how long is the model?
2	A model window is 4 cm wide at 1:20 scale. How wide is the real window?
3	A bridge is 50 m long. At 1:100 scale, how long is the drawing?
4	A model car is 12 cm long at 1:25 scale. How long is the real car?
5	A classroom is 8 m wide. At 1:50 scale, how wide is the drawing?

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Lettering Practice Peer Feedback (Folio pp. 48–49)

After practising your technical lettering, swap with a partner and give feedback.

One thing they did well	One area to improve

🔵 Support — Scale Calculation Steps

Follow these steps for EVERY scale problem:

What unit? Convert metres to centimetres first
Model or real? Am I finding the model (divide) or real size (multiply)?
Calculate: Do the maths
Sense check: Does my answer seem reasonable?

Key Facts

1 m = 100 cmModel = smallerReal = bigger Smaller → divideBigger → multiply

🟠 Extension — Advanced Scale

Enlarging: A phone is 15 cm long. At 2:1 scale (enlarging), how long is the drawing?

Find the scale: A model is 8 cm and the real object is 2 m. What is the scale?

Multi-scale: Draw a textbook (30 cm × 21 cm) at 1:2 AND 1:5 scale. Calculate both sets of dimensions.

Scale	Scaled length	Scaled width
1:2
1:5

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Exit Ticket — Reflection

1. What does 1:20 scale mean? Explain in your own words.

2. A room is 4 m wide. At 1:20 scale, how wide is the model? Show your working.

3. Name ONE rule of technical lettering.

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Self-Assessment

Success Criteria	Got it 🟢	Nearly there 🟠	Need help 🔴
I can write neat, consistent technical letters	●	●	●
I can explain what scale means (e.g. 1:2, 1:10)	●	●	●
I can calculate scaled dimensions	●	●	●
I can apply scaling to simple objects	●	●	●