Scaling in Drafting involve the use of ratio and proportion

1. MECHANICAL DRAFTING
ARCHIBALD S. SALANGSANG
SECONDARY SCHOOL TEACHER I

2. MECHANICAL DRAFTING
SCALING
• PROPORTION – a size or distance in comparison
to another.
• PROPORTION SCALE – a scale for measuring
distances for drawings. Marks on a proportion
scale indicate the reduced size in proportion to the
full or actual scale.
• SCALE – a graduated measurement to allow
production of a drawing to any size desired.

3. MECHANICAL DRAFTING
THE SCALE
• The measuring tool,
called the SCALE
(commonly known as the
metric scale), has several
edges.
• Each edge is called the
PROPORTION SCALE.

4. MECHANICAL DRAFTING
THE SCALE
• It helps the drafter to
REDUCE or ENLARGE
the drawing of an object
in proportion to its actual
size.

5. MECHANICAL DRAFTING
FUNCTION OF A SCALE
1. To measure or layout line distances accurately
either in full size and larger or smaller than full size.
2. To produce drawing to a certain sizes (making drawing
into scale)

6. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
PROPORTION SCALES
Most drafting scales are equipped with proportion scales.
Each of these scales aids the drafter in reducing an object
on a drawing in a different proportion.

7. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
FULL-SIZE SCALE – has a ratio of 1:1
• This means that 1 mm on the drawing represents 1 mm
of the actual object.
• The views on the drawing paper are the same size as
those of the actual object.

8. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
SCALE RATIO 1 : 1 – means that 1 mm. on the drawing
represent 1 mm. on the actual product or work piece.

9. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
REDUCED SCALE (SCALED-DOWN) – has a ratio of 1:2.
This means that 1 mm on the drawing represent 2 mm on
the actual object.
The views of the actual object are twice the size of the
views on the drawing paper.

10. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
REDUCED SCALE (SCALED-DOWN)
This scale is usually used to draft huge/large actual objects
so that they can fit into the drawing paper. Common
reduction scales used are :
1: 25 1:50 1:100 1:200 1:250
1: 10 1:20 1:40 1:300 1:500

11. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
ENLARGED SCALE (SCALED-UP) – has a ration of 2:1
This means that every 2 mm on the drawing represent 1
mm on the actual object.
The views on the drawing paper are twice the size of
those of the actual object.

12. MECHANICAL DRAFTING
THE SCALE RATIO
(OBJECT/DRAWING)
ENLARGED SCALE (SCALED-UP)
This scale is primarily used in drafting small/tiny objects so
that its details can be more presented in the drawing
paper. Common enlargement scales used are
2: 1 5:1 10:1 50:1
100:1 200:1 250:1 500:1

13. MECHANICAL DRAFTING
THINGS TO REMEMBER
IN SCALING A DRAWING
1. Whenever possible, the work piece must be drawn into
full-size.

14. MECHANICAL DRAFTING
THINGS TO REMEMBER
IN SCALING A DRAWING
2. When dimensioning,
always enter the
actual dimension of
the work piece.

15. MECHANICAL DRAFTING
THINGS TO REMEMBER
IN SCALING A DRAWING
3. Angular dimensions remain the same regardless of the
scale to which an object is drawn.

16. MECHANICAL DRAFTING
THINGS TO REMEMBER
IN SCALING A DRAWING
4. The first figure of a scale designation refers to the
dimension used to construct the views.
The second figure of a scale designation refers to the
actual dimensions of the object being drawn.