Unit 2.Drawing applied to technology

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

Unit 2.Drawing applied to technology

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 m2 (A0) four times by half the longest side.

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

2.1 Drawing materials and instruments

Pencil hardnessThe 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 hard Hard Medium Soft Very soft

6H 5H 4H 3H 2H H HB B 2B 3B 4B 5B 6B

less clay

More clay

Technique draw

Artistic draw

2.1 Drawing materials and instruments

Mechanical pencilsThey hold a graphite lead. They can be used for

technical drawing (if used )with a soft lead.

ERASERSErasers are made of rubber, they absorb

graphite and erase it.

2.1 DRAWING TOOLS

THE RULERIt 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

2.1 Drawing materials and instrumentsHow 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

2.1 Drawing materials and instruments

Activity :Draw a chessboard using the set square. The separation between

squares is 2 cm!

square16 cm

16 cm

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

2.1 Drawing materials and instruments

Drawing angles exercise: you have to obtain, 45º, 75º, 90º, 120º

angles combining the set squares

2.1 Drawing materials and instruments

Drawing angles exercise: you have to obtain, 45º, 75º, 90º, 120º angles combining

the set squares

2.1 Drawing materials and instruments

The CompassIt is used for drawing circles and angles

Advice: sharpen the lead tip by rubbing it on a fingernail file

2.2 DRAFT AND SKETCH

DRAFT: It is a free hand drawing (just with a pencil). We show an idea or object without totally defining it.

Page 41

2.2 DRAFT AND SKETCH

ATTENTION! A DRAFT IS NOT A BAD

DRAWING AND A SKETCH IS NOT A GOOD DRAWING !!!!!!

2.2 DRAFT AND SKETCH

The sketch: It is a free hand drawing too, but it includes the measures, therefore it shows the precise size and a shape similar to the final drawing.

measure

Page 41

2.2 DRAFT AND SKETCH

Activity: draw a sketch of your home cupboard.

2.2 DRAFT AND SKETCH

the Sketch

2.3 Drafting scale

We define scale as the relation between the drawing size and the real object

A model uses a reduction scale

2.3 Drafting scale

1:2

The Drawing size

The Real size

Page 38

2.3 Drafting scale

1200 reality1cm drawing

1:1200

1 cm measured on the drawing is equivalent to 1200cm in reality

Page 38

2.3 Drafting scale

Scale types:• Reduction scale: it is used to

represent big objects, so they can be drawn on paper– We usually use: 1:2 1:5 1:10…In this example we have reduced 1000

times the real size of the tree

1:1000 Realdrawn RealReal

2.3 Drafting scaleEnlargement scale: it is used to

represent small objects so we can see them on paper

– It is used: 2:1 5:1 10:1 …

In this example the drawing is two times the real object

2:12:1

Drawing

Real

Safety pin

2.3 Drafting scale

An example of scale application• Let’s draw a pencil that is 10cm

high and 1cm wide using different scales: 2:1, 1:2, 1:41cm

10cm

2.3 Drafting scale

Scale 2:1

High wide

Drawn 2

Real 1 10 1

Real

2:1

2.3 Drafting scale

Scale 1:2

High wide

Drawn 1

Real 2 10 1

2:1

Real

1:2

2.3 Drafting scale

Scale 1:4

High wide

Drawn 1

Real 4 10 1

Real

2:1

1:2

1:4

Real

2:1

1:2

Real

1:2

2:1

Real

1:2

2.3 Drafting scale

Scale exercise• This drawing is 4,5cm long and 2,5

cm high, if we have used a 1:100 scale How high and long is the real car?

4.5cm

2.5

cm

2.3 Drafting scale

Scale 1:100

Long High

Drawn 1 4,5 2,5

Real 100 450 250

4.5

cm

2.5cm

2.3 Drafting scale

• Activity:Let’s draw a plan of your classroom

using your feet and your hands applying the suitable scale to draw it

1 foot: 20cm

1 hand: 10cm

31 feet are equivalent to 620cm

24 feet are equivalent to 480cm

4,5 hands = 45cm

3,5 hands=35cm

Therefore we have

2.3 Drafting scale

4hands x 18cm/hand= 72cm

3hands x 18cm/hand= 54cm

31 feet x 20cm/foot= 620cm

24 feet x 20cm/foot=480cm

2.3 Drafting scale

Which scale could we use to draw the classroom and your desks on your notebooks?length width

Classroom 620cm 480cm

Desk 72cm 54cm

Classroom Long wide

Drawn 1 6,2 4,8

Real 100 620 480

Desks Long wide

Drawn 1 0,72 0,54

Real 100 72 54

2.3 Drafting scaleLet’s use the 1:100 scale, so the drawing will be 100 times smaller than reality

2.3 Drafting scale

• Homework:Draw a plan of your bedroom using your

feet and your hands. Apply a 1:25 scale to draw it

1 foot: 20cm

1 hand: 10cm

15feet= 300cm

20 pies = 400cm

habitación lenght Wide

bedroom 330 200

Desk 150 150

Bed 100 70

2.4 Diedric system

2.4 Diedric system

The diedric system represents the objects using a perpendicular projection on a plane

2.4 Diedric systemThe projection or VIEW consists of drawing just

what we see when we are perpendicular to the object and to the plane

Page 28

2.4 Diedric systemTo define an object we only need 3 views, floor, front and

profile: Floor view: from the top of the object Front view: facing the object Profile view: from the side

Profile view

Floor view

Front view

Front view

Floor view

Profile view

Draw the left profile, floor and front view of your pencil case.

2.4 Diedric system

Diedric RulesThe front is usually indicated with an arrowThe views distribution

The front is always on top of the floor The profile is situated the other way round,

that is, the left profile is situated on the right

front

floor

Left profile Right profile

floor

front

2.4 Diedric systemRemember: The same height: the object has the same height on the

floor and on the profile views The same width: on the front and on the floor views The same depth: on the floor and on the profile views

2.4 Diedric system

Exercise: Draw the front, left profileand floor views of the class chair

2.4 Diedric system

Exercise: Draw the front, profile and floor views of the class chair

2.4 Diedric system

Where do we have to be situated to see these objects like circles?

2.4 Diedric system

2.4 Diedric systemExercise 11: Complete the views of the following objects

Page 31

2.4 Diedric systemExercise 11: Complete the views of the following objects

2.4 Diedric systemExercise 11: Complete the views of the following objects

2.4 Diedric systemExercise 11: Complete the views of the following objects

2.4 Diedric system

Non visible lines: when we know there is a hidden line we have to draw it using a discontinuous line

hidden line

2.4 Diedric system

Insert video

2.4 Diedric system

Activity: draw the front, floor and right profile views of this figure colouring each face in one colour.

2.4 Diedric system

Activity: draw the front, floor y left profile views of this figure colouring each face in a different colour.

2.4 Diedric system

Exercice: draw the right profile, front and floor views of these objects

2.4 Diedric system

2.4 Diedric system

2.5 Marking and standardizing

The standardizing is the group of rules that defines technical drawing.

For example: For paper size we use the DIN rule: A0,A1,A2… The lines are:

Thick continuous lines: are used to outline objects Thick discontinuous lines: indicate hidden lines Thin continuous lines: are used for auxiliary measures

and reference lines

2.5 Marking and standardizing

Measure line

Auxuliary Line

Measure

Reference line

2.5 Marking and standardizing

Outside thick continuous line

Thick discontinuous line for a hidden edge

2.5 Marking and standardizing

Marking : indicating the real dimensions above the object

2.5 Marking and standardizing

Activity: draw these views indicating which rules are broken

Correct WrongCorrect WrongCorrect WrongCorrect Wrong

2.5 Marking and standardizing.

The measure lines: We place them parallel to

the edge and slightly separated

They are limited by the auxiliary lines

The arrows are thin and enlongated, they go from one side to the other

Marking follows some rules: see page 37

2.5 Marking and standardizing Auxiliary lines

We place them perpendicular to the measure lines

They cross the measure line a little bit

They never cut the measure line

2.5 Marking and standardizing

Activity: draw these views indicating which rules are broken

Correct Wrong

2.5 Marking and standardizing The measures:

We indicate the real measure in milimetres, but “mm” is never written

They are placed above the measure line, never under it

We only use the extrictly necessary measures

2.5 Marking and standardizing

Activity: draw these views indicating which rules are broken

Correct Wrong

Activity: Draw the front, left profile and floor views of your pencil marking the measures

2.5 Marking and standardizing

Let’s revise the important terms

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

Unit 2.Drawing applied to technology

Vocabulary

Paper size Cellulose Clay, graphite, lead Hard and soft pencils Erasers, technical pencil Sixty and forty-five degree rules Sketch, draft, free hand drawing, measures Scale, real and drawn size, reduction, enlargement

scales To be reduced 100 times… Length, height, width Long, high, wide.