1. TECHNICAL DRAWING

2. Unit 2.Drawing applied to technology

3. What are we going to see in this unit? 2.1 Drawing tools and how to use them 2.2 Drafts and sketches 2.3 Drafting scale 2.4 Diedric system 2.5 Marking and standardizing

4. 2.1 Drawing materials and instruments Paper Paper is made of cellulose that is obtained from trees The paper size that we use is A4. It is the result of dividing 1 m 2 (A0) four times by half the longest side.

5. 2.1 Drawing materials and instruments Pencil A pencil has a lead covered with wood. The lead is made with graphite and clay clay Graphite Lead Wood cover

6. 2.1 Drawing materials and instruments Pencil hardness The more clay it contains the harder the lead will be. We use letter H for hard pencils and letter B for soft ones. Hard: H Soft: B Very hardHardMediumSoftVery soft 6H5H4H3H2HHHBB2B3B4B5B6B less clay More clay Technique drawArtistic draw

7. 2.1 Drawing materials and instruments Mechanical pencils They hold a graphite lead. They can be used for technical drawing (if used )with a soft lead. ERASERS Erasers are made of rubber, they absorb graphite and erase it.

8. 2.1 DRAWING TOOLS THE RULER It is a precision tool that makes it possible to measure and to transfer a distance. TRIANGULAR SET SQUARE A set square is a tool for drawing perpendicular (vertical) and parallel lines and for obtaining angles. There are 2 types of trianglular set squares A 45 degree A 60 degree

9. 2.1 Drawing materials and instruments How to draw vertical and parallel lines with the set square Vertical: Parallel: Activity: Draw the set squares in your notebook as you can see them in both positions

10. 2.1 Drawing materials and instruments Activity :Draw a chessboard using the set square. The separation between squares is 2 cm! square 16 cm

11. 2.1 Drawing materials and instruments Drawing angles: we can get 15º, 30º, 45º, 60º, 75º, 90º, 120º, 135º…angles combining the 30º, 45º, 60º and the 90º angles from the set squares You don't have to copy them because you can find them in your text book on page 25

12. 2.1 Drawing materials and instruments Drawing angles exercise: you have to obtain, 45º, 75º, 90º, 120º angles combining the set squares

13. 2.1 Drawing materials and instruments Drawing angles exercise: you have to obtain, 45º, 75º, 90º, 120º angles combining the set squares

14. 2.1 Drawing materials and instruments The Compass It is used for drawing circles and angles Advice: sharpen the lead tip by rubbing it on a fingernail file