Technology 3
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Scale drawings
1.4 SCALE DRAWINGS
A scale drawing is a drawing that
represents a real object.
The scale of the drawing is the ratio of the
size of the drawing to the REAL size of the
object.
NUMERICAL
GRAPHICAL
NATURAL SCALE
When the drawing of
the object has the
same dimensions
as the real object. Its scale is 1:1
1.4.1 Reduction Scale:
The object is proportionally reduced on the drawing
Normalized scales
1:2 (or 1/2 ): Pronounced "One to Two". HALF SIZE : 1 millimeter on paper =2
millimeters on the artifact. The drawing is half the size of the artifact.
1:4 (or 1/4 ): Pronounced "One to Four"
Other normalized scales: 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000,
1:5000, 1:10000
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Technology 3
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Scale drawings
How to understand the measurements on a reduced scale drawing?
1.4.2 Enlargement scale
Small objects (like chips, screws...) can be too small to be draw, so we use an
enlargement scale so that the drawing is proportional to the object but bigger.
Some of the most commons enlargement scales are:
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Technology 3
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Scale drawings
EXERCISES
1. Think of how you can draw this objects on a piece of paper and complete
the table below:
THE SAME BIGGER SMALLER
Your city map
Your home plan
A car
A pair of scissors
A pencil
A pencil sharpener
Machinery inside a
watch
A molecule
2. What are these scales enlargement, reduction or natural scales?
Scale
1:2
5:1
1:10
20:1
10:1
Natural scale example
Reduction scale example
Enlargement scale example
3. Follow the examples and complete these scales tables values
Scale
Drawing
Reality
Scale
Drawing
5:1
20 mm
100 mm
2:1
24mm
1:50
4 cm
200 cm
50:1
50cm
1: 10
10 cm
10:1
2,4cm
1:50
20 cm
10:1
1,5cm
1:1000 25 cm
50:1
0,7.m
1:5000
23 cm
1:1
1:2
12 mm
1:5
10 cm
12cm
2,6 cm
1000 m
100 m
Reality
2:1
1,3 mm
16,7 cm
26 cm
13 mm
4. The length of the highway is 600 km. If 0.5 cm represents 50 km, what is the
length of the highway on the map?
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Scale drawings
5. The dimensions of a building are 250 m by 120 m. If 1 cm represents 20 m on
a scale drawing, what are the dimensions of the building on the drawing? What
is the scale?
9. Write the numbers on the dimension lines of this truck, which is drawn to a
scale 1/50.
10. Write the value of the length indicated on the screw (drawn to a natural
scale 1/1).
11. To what scale is this basket field drawn (it is dimensioned in m).
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12. Draw this piece to a scale 1/250.
13. Dimension this house to scale 1/100.
14. Dimension this room to scale 1/50.
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Scale drawings
Technology 3
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Scale drawings