Drawing and Drawing Instrument – JSS1 Basic Technology Lesson Note (Second Term)

Technical drawing is a universal language that engineers, technicians, builders and draughtsmen use to show the shape, size and features of objects.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define technical drawing and name some technical people;
2. list common drawing instruments and materials and state the use of each;
3. identify the drawing instruments made of acrylic;
4. state ways of caring for and storing the drawing board, tee square, set square, scale rule, protractor, compass and divider.

What is technical drawing?

Technical drawing is a universal language used for communication among technical people.

• Meaning: it is expressed in graphical illustrations that show the shape, size and other features of engineering components.
• Where it is used: in the manufacturing and construction industries.
• Technical people: engineers, technicians, builders, draughtsmen and so on.

Why do we study drawing?

We study drawing so that we can show other people what we have in mind without talking or writing too much.

• Communication: a drawing is understood by people who speak different languages.
• Clarity: it shows shape and size more clearly than words.
• Planning: builders and makers use drawings to plan work before they start.
• Accuracy: constant practice with the right instruments gives neat and correct drawings.

What are drawing instruments and materials?

Drawing instruments and materials are the tools and supplies used to make accurate technical drawings.

• Instruments: tools such as the tee square, compass and divider.
• Materials: supplies such as drawing paper, pencil and adhesive tape.

What are the common drawing instruments and materials?

There are eleven common drawing instruments and materials, listed with their uses below.

Which drawing instruments are made of acrylic?

Acrylic is a transparent plastic, and seven drawing instruments and materials are made from it.

• Why acrylic is used: it is transparent, so the drawing can be seen through the instrument.
• Weakness: it scratches easily and can bend or melt near heat.

How do you care for and store drawing instruments and materials?

Drawing instruments last longer and stay accurate when they are used correctly, kept clean and stored safely.

How do you care for the drawing board?

1. Do not use pins to fasten your paper to the board. Use tape or clips instead.
2. Do not use a razor blade to cut anything on the surface.
3. Always cover the surface with cardboard.
4. Keep the drawing board in a safe place.

How do you care for the tee square?

1. Never use the tee square as a walking stick.
2. Do not use a pen knife or blade along the edge of the tee square.
3. Always hang your tee square after use.
4. Always keep your tee square clean.

How do you care for the set square, scale rule and protractor?

1. Do not use any sharp objects on them.
2. Keep them away from fire.
3. Always keep them in a safe place after use.

How do you care for the compass and divider?

1. Do not sit or step on them.
2. When not in use, keep them in a safe container.
3. Never use a compass or divider as a paper holder.
4. Do not use the needle point to punch holes.

Evaluation

1. Define technical drawing and list five examples of technical people.
2. List five examples each of (a) acrylic materials and (b) non-acrylic materials.
3. Mention two ways by which you can take care of the drawing board.
4. Mention two ways by which you can take care of the set square and protractor.
5. State the use of the tee square and the divider.

Assignment

State why we study drawing, then mention two ways of caring for the tee square and two ways of caring for the compass.