Technical drawing is the method of
communication that is specific to the field of
It is used to represent the objects that we
design and built.
Ingredients of technology
Ingredients of technology
Now, let´s learn the basic drawing
Pencils are made of wood and a graphite
core, called lead.
Pencil leads are classified by hardness as
8B to 3B
2 or 3
2B, B, HB
4 or 5
• Letters: H
6 to 9
6H to 10H
When we write, the graphite latch on to the
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.
Hard Pencils are used
for plans and
technical drawing .
Soft Pencils are used for
sketches and artistic drawing.
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.
The lead of the propelling pencils can
Different diameters, to fit into a lead into
the reservoir tube.
Rubbers are used to correct errors made
when writing with pencil.
White vinyl rubbers are
When you erase:
Follow the direction the line was draw in.
Use smooth movements so the paper doesn´t
Technical pens are used to trace over
with ink the lines previously drawn with a
the lines a
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.
SET OF SQUARES
The set of squares are two right triangles used
to draw paralel and perpendicular lines.
They let us to draw
combining the measures
of the angles of the set .
90º+45º = 135º 30º+45º = 75º
60º+45º = 105º 90º+60º = 150º
The protactor is used to measure or draw
It used to be semicircular
and is divided into 180
The stencils are used when standard symbols
are to be drawn repeatedly. They have
standard symbols cut in it.
The compass is an instrument used to draw
circunferences or circular arcs, as well as to
It can be adjusted to
hold a technical pen.
Or with an
to draw bigger
The paper is the basis for all technical
Paper can be clasified by:
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)
A0 is a rectangle with an area of 1 m2.
Each format is
format in half.
The format we usually use is the A4
The weight of the paper indicates how thick or
thin it is.
Usually the weight is
indicated in grams
per square metre.
The finish of the paper shows the appearance
of the surface of the paper.
It can be white
It can be rough or
It can be brilliant or
It can be opaque or