TECHNICAL

DRAWING

Drawing

Technical drawing is the method of communication that is specific to the field of technology

It is used to represent the objects that wedesign and built.

Ingredients of technology

Drawing

Now, let´s learn the basic drawing

instruments

Ingredients of technology

Pencils are made of wood and a graphite

core, called lead.

PENCIL

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

PENCIL

When we write, the graphite latch on to the

paper.

If the pencil is a hard one theamount of graphite is a bit one, and the mark in thepaper is light.

On the other hand if it´s a softone the amount of graphite isbigger, and the mark is dark.

Soft Pencils are used for

sketches and artistic drawing.

PENCIL

Hard Pencils are used

for plans and

technical drawing .

Propelling pencils have a lead into a

body, commonly made of plastic.

PROPELLING PENCIL

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 have:

Different hardness

Different diameters, to fit into a lead intothe reservoir tube.

PROPELLING PENCIL

Diameter

Hardness

White vinyl rubbers are

recommendes.

RUBBER

Rubbers are used to correct errors made

when writing with pencil.

When you erase:

Follow the direction the line was draw in.

Use smooth movements so the paper doesn´twrinkle

Technical pens are used to trace over

with ink the lines previously drawn with a

pencil

TECHNICAL PEN

Technicalpens are calibratedand givesthe lines a standarizedwidth.

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.

The set of squares are two right triangles used

to draw paralel and perpendicular lines.

SET OF SQUARES

They let us to draw

differents angles

combining the measures

of the angles of the set .For example:

90º+45º = 135º 30º+45º = 75º60º+45º = 105º 90º+60º = 150º

leg

leg

The protactor is used to measure or draw

angles.

PROTACTOR

It used to be semicircular

and is divided into 180

degrees.

The stencils are used when standard symbols

are to be drawn repeatedly. They have

standard symbols cut in it.

TEMPLATES

The compass is an instrument used to draw

circunferences or circular arcs, as well as to

measure segments.

COMPASS

It can be adjusted to

hold a technical pen.

Or with anextension pieceto draw biggercircunferences

The paper is the basis for all technical

drawings.

PAPER

Paper can be clasified by:

Size

Weight

Finish

There are different sizes of paper. They are

also called formats.

PAPER (Size)

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.

PAPER (Size)

Each format is

calculated by

dividing the

previous

format in half.

The format we usually use is the A4

(297x210 mm)

The weight of the paper indicates how thick or

thin it is.

PAPER (Weight)

Usually the weight is

indicated in grams

per square metre.

More grams

implies a

thicker paper

The finish of the paper shows the appearance

of the surface of the paper.

PAPER (Finish)

It can be whiteor coloured

It can be brilliant ordull

It can be rough orsmooth

It can be opaque ortranslucent