This document discusses the basic tools and materials used for technical drawing. It describes pencils of varying hardness for sketches and plans, propelling pencils for consistent lines, erasers for corrections, pens for tracing lines, rulers and sets of squares for straight and angled lines, protractors for measuring angles, templates for standard symbols, compasses for circles, and paper of different sizes, weights, finishes for the base. Technical drawing uses these tools to precisely communicate engineering and design concepts.

1. TECHNICAL
DRAWING

2. Drawing
 Technical drawing is the method of
communication that is specific to the field of
technology
 It is used to represent the objects that we
design and built.
Ingredients of technology

3. Drawing
Ingredients of technology
 Now, let´s learn the basic drawing
instruments

4. PENCIL
 Pencils are made of wood and a graphite
core, called lead.
 Pencil leads are classified by hardness as
follows:
Soft
•Numbers:
0 or1
• Letters:
8B to 3B
Medium
•Numbers:
2 or 3
• Letters:
2B, B, HB
and F
Hard
•Numbers:
4 or 5
• Letters: H
to 5H
Very hard
•Numbers:
6 to 9
• Letters:
6H to 10H

5. PENCIL
When we write, the graphite latch on to the
paper.
 If the pencil is a hard one the
amount of graphite is a bit
one, and the mark in the
paper is light.
 On the other hand if it´s a soft
one the amount of graphite is
bigger, and the mark is dark.

6. PENCIL
 Hard Pencils are used
for plans and
technical drawing .
 Soft Pencils are used for
sketches and artistic drawing.

7. PROPELLING PENCIL
 Propelling pencils have a lead into a
body, commonly made of plastic.
 Propelling pencils provide lines of constant
thickness without sharpening.
 They are used in technical drawing (not in
artistic drawing) and writing.

8. PROPELLING PENCIL
 The lead of the propelling pencils can
have:
 Different hardness
 Different diameters, to fit into a lead into
the reservoir tube.
Diameter
Hardness

9. RUBBER
 Rubbers are used to correct errors made
when writing with pencil.
White vinyl rubbers are
recommendes.
 When you erase:
 Follow the direction the line was draw in.
 Use smooth movements so the paper doesn´t
wrinkle

10. TECHNICAL PEN
 Technical pens are used to trace over
with ink the lines previously drawn with a
pencil
 Technical
pens are
calibrated
and gives
the lines a
standarized
width.

11. RULER
 Rulers are instruments used to draw straight
lines and measure segments.
Common ruler: It´s
marked along one side.
Engineer´s scale: It´s a
triangular prism on which
the six most common
scales are etched.

12. SET OF SQUARES
 The set of squares are two right triangles used
to draw paralel and perpendicular lines.
 They let us to draw
differents angles
combining the measures
of the angles of the set .
For example:
90º+45º = 135º 30º+45º = 75º
60º+45º = 105º 90º+60º = 150º
leg
leg

13. PROTACTOR
 The protactor is used to measure or draw
angles.
 It used to be semicircular
and is divided into 180
degrees.

14. TEMPLATES
 The stencils are used when standard symbols
are to be drawn repeatedly. They have
standard symbols cut in it.

15. COMPASS
 The compass is an instrument used to draw
circunferences or circular arcs, as well as to
measure segments.
 It can be adjusted to
hold a technical pen.
 Or with an
extension piece
to draw bigger
circunferences

16. PAPER
 The paper is the basis for all technical
drawings.
 Paper can be clasified by:
 Size
 Weight
 Finish

17. PAPER (Size)
 There are different sizes of paper. They are
also called formats.
 In technical design, the most common
formats are the “A” series, based on the
DIN (Deutsche Industrienorm)

18. PAPER (Size)
 A0 is a rectangle with an area of 1 m2.
 Each format is
calculated by
dividing the
previous
format in half.
 The format we usually use is the A4
(297x210 mm)

19. PAPER (Weight)
 The weight of the paper indicates how thick or
thin it is.
 Usually the weight is
indicated in grams
per square metre.
 More grams
implies a
thicker paper

20. PAPER (Finish)
 The finish of the paper shows the appearance
of the surface of the paper.
 It can be white
or coloured
 It can be rough or
 It can be brilliant or
dull
smooth
 It can be opaque or
translucent