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JSS1: BASIC TECHNOLOGY - 2ND TERM

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Lesson 3, Topic 4
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Common Drawing Instruments

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1. Drawing Board:

This is a flat wooden board with a smooth, rigid surface. It is of different sizes depending on where it is used as shown in the table below.

2. Tee-square:

This is a T-shape instrument containing a head and a stock. It is used for drawing horizontal lines, for setting the paper on the board and also to support the set square during drawing. It is placed on the drawing board with a stock at the left-hand edge of the board. It can be made of wood or plastic.

3. Set-square:

These are instruments in the form of a right-angled triangle, made of plastic. We have the 45Â° and 30Â°/60Â° set squares. They are used for drawing vertical and angled (slanted) lines. They can be made of plastic or wood.

4. Scale Rule:

This is a 30cm wooden or plastic ruler, used for measuring lengths and dimensions of scale drawings. It is a three-sided ruler used by architects to convert dimensions into a smaller drawing of a building plan and readers of blueprints to translate the drawing into the real sizes for construction.

5. Protractor:

The protractor is a plastic semi-circular instrument, used for measuring angles in degrees.

6. French curves and Flexible curves:

This instrument is used to draw different types, sizes, and shapes of curves. It enables one to draw curves that would be difficult to achieve with a compass. The flexible curves are used for the same purpose.

7. Drawing set:

This is a pack containing different drawing items like a pair of compasses and dividers.

8. Compass:

A compass is used for drawing circles and arcs. There is the small bow compass and the largeâ€“size compass.

9. Divider:

It resembles a compass but has two pin edges. It is used for copying lengths, i.e. transferring measurements from the metric rule to the drawing. It is also used for scribing circles or semi-circles on metal surfaces.