DTMI Fundamentos 1

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MCA08677 - DESENHO TÉCNICO MECÂNICO I
Prof.:Antônio Bento Filho 
Departamento de Engenharia Mecânica 
Universidade Federal do Espírito Santo - ufes 
!1
FUNDAMENTOS DO DESENHO MECÂNICO
Referências: 
Narayana, K.L., Kannaiah, P., Venkata Reddy, K., 2007. Machine drawing. New Age 
International. 
Provenza, F., 1987. Desenhista de máquinas. Pro-Tec.
I. INTRODUÇÃO
a.Linguagem Gráfica 
✴ Em geral, é utilizada entre as pessoas como poderoso meio 
de intercâmbio e comunicação de idéias de temas técnicos; 
✴ Para o efetivo intercâmbio de idéias o engenheiro deve 
compreender: 
★A linguagem falada e escrita; 
★Os Símbolos básicos utilizados na engenharia; 
★A Linguagem Gráfica. 
✴ Independe das barreiras de linguagem. 
✴ Desenho técnico: ano 500 AC rei Pharos do Egito; símbolos 
foram usados para troca de idéias entre pessoas.
Linguagem universal entre engenheiros.
!2
b.LINGUAGEM GRÁFICA
✴ Importância da linguagem gráfica: expressa idéias as 
quais não é possível transmitir apenas com a linguagem 
falada e escrita; 
✴ Precisão: preparado por qualquer pessoa com formação 
técnica o desenho técnico deve ser claro, preciso e deve 
possibilitar uma única interpretação; 
✴ Não seria possível produzir as máquinas/automóveis/
aviões/etc. em grande escla com um elevado número de 
montagens e sub-montagens sem desenhos claros, 
corretos e precisos.
!3
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
a. Desenhos de 
máquinas: 
• Partes ou componentes; 
• Apresentado em vistas 
ortográficas; 
• Tamanho e forma devem 
ser completamente 
entendidos; 
• Desenhos de projeto, 
fabricação e montagem.
!4
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
b.Desenhos de 
fabricação: 
✴Desenho de trabalho: 
Deve conter as 
informações de 
material, dimensões, 
tolerâncias, 
acabamento, 
tratamento térmico, 
etc. necessárias para 
orderientar a 
fabricação da peça.
!5
CLASSIFICAÇÃO DOS DESENHOS TÉCNICOS
c. Desenhos de montagem: desenho que mostra as partes da 
máquina na sua posição de trabalho 
• Desenho de montagem na fase de projeto: quando uma máquina é 
projetada, um desenho de montagem ou lay-out é realizado para 
visualizar o conjunto.
• Desenho de montagem detalhado: usualmente feito para máquinas 
simples com poucas partes. Todas informações e dimensões para 
construção são dadas diretamente no desenho de montagem .
• Vistas separadas de partes em escala aumentada mostrando 
ajuste das peças podem ser incluídas no desenho de montagem.
!6
Classificação dos desenhos técnicos
Desenhos de montagem
!7
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
✴Desenho de sub-montagem: é um desenho de montagem de um 
grupo de peças que compõem um sub-conjunto da montagem 
principal de um navio, avião, motor diesel, automóvel, máquina 
operatriz, etc. 
✴Desenho de instalação e montagem: a localização e dimensão de 
algumas partes importantes e dimensões globais da unidade montada 
são mostrados. Fornece informações úteis para montagem e mostra as 
partes da máquina em suas posições de trabalho corretas na montagem.
✴Desenho de montagem para catálogos: são preparados para catálogo 
de produtos. Tipicamente mostram detalhes e dimensões que 
despertarão o interesse do potencial comprador, e as dimensões 
principais.
!8
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
✴Desenho de montagem para catálogos
!9
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
✴ Desenho de montagem para 
manuais de instrução: São 
utilizados para montagem e 
instalação no local, quando a 
máquina é entregue preparada 
para montagem. 

Cada componente é numerado 
para permitir a montagem 
correta.
!10
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
✴Vista explodida de desenho de 
montagem: para manuais de 
instrução e catálogo de 
componentes.
!11
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
Desenhos para patentes: utlizados para 
ilustrar e explicar o invento, são desenhos 
pictóricos que devem ser auto-explicativos. 
É essencial que estejam mecanicamente 
corretos e incluam ilustrações completas de 
todos os detalhes da invenção. 

Estes desenhos não são úteis para a 
fabricação.
!12
✴ Desenho de 
montagem 
esquemático: facilita o 
entendimento do 
princípio de operação 
da máquina ou sistema. 

É uma ilustração 
simplificada 
substituindo todos 
elementos por suas 
respectivas 
representações. 

A figura ao lado é a 
representação 
esquemática de um 
trem de engrenagens.
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
!13
CLASSIFICAÇÃO DOS DESENHOS 
TÉCNICOS
Desenho para 
usinagem: Peças 
fundidas e forjadas 
devem ter acabamento 
através de operações de 
usinagem. 

As informaçãoes do 
processo anteior não 
contém as especificações, 
caracterísitcas e 
dimensões finais e é 
emitido um desenho para 
a usinagem. 

Por este mesmo critério é 
possível haver desenhos 
de fundição, de forjaria, 
de caldeiraria, etc.
!14
I. EXERCÍCIOS DE APLICAÇÃO:
1.Classifique os vários tipos de desenhos usados na engenharia mecânica.
2.Explique o que é um desenho de máquina.
3.Defina o que é um desenho de fabricação.
4.Mostre a diferença entre um desenho de máquina e um desenho de fabricação.
5.O que é um desenho de montagem?
6.Liste os vários tipos de desenho de montagem.
7.O que quer significa um desenho detalhado de montagem?
8.O que é um desenho de sub-montagem?
9.O que é um desenho de montagem explodido e onde é utilizado?
10.Mostre a diferença entre desenhos para catálogos e para manuais de instrução.
11.O que significa desenho de montagem esquemático e onde ele é preferido?
12.O que é um desenho de usinagem e qual a diferença em relação a um desenho de máquina?
13.O que são desenhos de patentes e como são preparados?
!15
III. PROJEÇÕES ORTOGRÁFICAS
!16
Um objeto tem 3 dimensões: comprimento, largura e altura; 
Projeção é a representação de um objeto 3D em 
um plano 
Elementos da projeção: 
Objeto; 
Plano de projeção; 
Posição do observador; e 
Linhas de projeção;
III. PROJEÇÕES ORTOGRÁFICAS
!17
Projeção ortográfica: observador localizado no 
infinito e linhas de projeção paralelas; 
Sistemas de projeção mais comuns: 10 diedro e 
30 diedro
III. PROJEÇÕES ORTOGRÁFICAS
!18
O objeto é suposto posicionado no 1o Diedro; 
A Vista frontal é tomada com o observador posicionado à frente do Quadrante; 
A Vista superior é tomada com o observador posicionado acima do Quadrante; 
A Vista lateral esquerda é tomada com o observador posicionado à esquerda do Quadrante;
Sistema de projeções no 1o Diedro
44 Machine Drawing
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View fromthe left
View fromthe left
Profileplane
Vert
ical
plan
e
!"! #$%&'()* '+* ',%-././0* '1%&'01-2&.3* 4.$5)
!"!"6 4789*+:;<*=>8*+:;?=
The view from the front of an object is defined as the view that is obtained as projection on the
vertical plane by looking at the object normal to its front surface. It is the usual practice to
position the object such that its view from the front reveals most of the important features.
Figure 3.1 shows the method of obtaining the view from the front of an object.
Verti
cal
plane
View
from
the f
rontView
from
the f
ront
Hori
zont
al pl
ane
 
View
from
abo
ve
Vert
ical
plan
e
Hori
zont
al pl
ane
 Fig. 3.1 Principle of obtaining the Fig. 3.2 Principle of obtaining the
 view from the front view from above
!"!"@ 4789*+:;<*-A;B8
The view from above of an object is defined as the
view that is obtained as projection on the horizontal
plane, by looking the object normal to its top
surface. Figure 3.2 shows the method of obtaining
the view from above of an object.
!"!"! 4789*+:;<*=>8*)7C8
The view from
the side of an object is defined as
the view that is obtained as projection on the
profile plane by looking the object, normal to its
side surface. As there are two sides for an object,
viz., left side and right side, two possible views from
the side, viz., view from the left and view from the
right may be obtained for any object. Figure 3.3
shows the method of obtaining the view from the
left of an object.
Fig. 3.3 Principle of obtaining the
view from the left
Plan
o 
Vert
ical
Vist
a 
fron
tal
Plano 
horizontal
Observador 
(∞)
44 Machine Drawing
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View fromthe left
View fromthe left
Profileplane
Vert
ical
plan
e
!"! #$%&'()* '+* ',%-././0* '1%&'01-2&.3* 4.$5)
!"!"6 4789*+:;<*=>8*+:;?=
The view from the front of an object is defined as the view that is obtained as projection on the
vertical plane by looking at the object normal to its front surface. It is the usual practice to
position the object such that its view from the front reveals most of the important features.
Figure 3.1 shows the method of obtaining the view from the front of an object.
Verti
cal
plane
View
from
the f
rontView
from
the f
ront
Hori
zont
al pl
ane
 
View
from
abo
ve
Vert
ical
plan
e
Hori
zont
al pl
ane
 Fig. 3.1 Principle of obtaining the Fig. 3.2 Principle of obtaining the
 view from the front view from above
!"!"@ 4789*+:;<*-A;B8
The view from above of an object is defined as the
view that is obtained as projection on the horizontal
plane, by looking the object normal to its top
surface. Figure 3.2 shows the method of obtaining
the view from above of an object.
!"!"! 4789*+:;<*=>8*)7C8
The view from the side of an object is defined as
the view that is obtained as projection on the
profile plane by looking the object, normal to its
side surface. As there are two sides for an object,
viz., left side and right side, two possible views from
the side, viz., view from the left and view from the
right may be obtained for any object. Figure 3.3
shows the method of obtaining the view from the
left of an object.
Fig. 3.3 Principle of obtaining the
view from the left
Plan
o 
Vert
ical
Vista 
superior
Plan
o 
hori
zon
tal
Observador (∞)
44 Machine Drawing
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View fromthe left
View fromthe left
Profileplane
Vert
ical
plan
e
!"! #$%&'()* '+* ',%-././0* '1%&'01-2&.3* 4.$5)
!"!"6 4789*+:;<*=>8*+:;?=
The view from the front of an object is defined as the view that is obtained as projection on the
vertical plane by looking at the object normal to its front surface. It is the usual practice to
position the object such that its view from the front reveals most of the important features.
Figure 3.1 shows the method of obtaining the view from the front of an object.
Verti
cal
plane
View
from
the f
rontView
from
the f
ront
Hori
zont
al pl
ane
 
View
from
abo
ve
Vert
ical
plan
e
Hori
zont
al pl
ane
 Fig. 3.1 Principle of obtaining the Fig. 3.2 Principle of obtaining the
 view from the front view from above
!"!"@ 4789*+:;<*-A;B8
The view from above of an object is defined as the
view that is obtained as projection on the horizontal
plane, by looking the object normal to its top
surface. Figure 3.2 shows the method of obtaining
the view from above of an object.
!"!"! 4789*+:;<*=>8*)7C8
The view from the side of an object is defined as
the view that is obtained as projection on the
profile plane by looking the object, normal to its
side surface. As there are two sides for an object,
viz., left side and right side, two possible views from
the side, viz., view from the left and view from the
right may be obtained for any object. Figure 3.3
shows the method of obtaining the view from the
left of an object.
Fig. 3.3 Principle of obtaining the
view from the left
Plan
o 
Vert
ical
Plano de perfil
Vista lateral 
esquerda
Observador 
(∞)
III. PROJEÇÕES ORTOGRÁFICAS
!19
Representação das Vistas no 1o Diedro
Orthographic Projections 45
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!"# $%&'&()*)+,(- ,.- /+&0'
The different views of an object are placed on a drawing sheet which is a two dimensional one,
to reveal all the three dimensions of the object. For this, the horizontal and profile planes are
rotated till they coincide with the vertical plane. Figure 3.4 shows the relative positions of the
views, viz., the view from the front, above and the left of an object.
View
from
the
left
View
from
the
left
View
from
the
fron
t
View
from
the
fron
t
View
from
abo
ve
View
from
abo
ve
(a)
View from the frontView from the front View from the leftView from the left
View from aboveView from above
(b)
Fig. 3.4 Relative positions of the three views and the symbol
!"1 2&'+3(*)+,(- *(2- %&4*)+/&- $,'+)+,('- ,.- /+&0'
An object positioned in space may be imagined as surrounded by six mutually perpendicular
planes. So, for any object, six different views may be obtained by viewing at it along the six
directions, normal to these planes. Figure 3.5 shows an object with six possible directions to
obtain the different views which are designated as follows:
1. View in the direction a = view from the front
2. View in the direction b = view from above
3. View in the direction c = view from the left
Vista Frontal
Vista Superior
Vista Lateral Esquerda
Sinal correspondente à 
projeções no 1o diedro.
Épura
Rebatimento
Orthographic Projections 45
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!"# $%&'&()*)+,(- ,.- /+&0'
The different views of an object are placed on a drawing sheet which is a two dimensional one,
to reveal all the three dimensions of the object. For this, the horizontal and profile planes are
rotated till they coincide with the vertical plane. Figure 3.4 shows the relative positions of the
views, viz., the view from the front, above and the left of an object.
View
from
the
left
View
from
the
left
View
from
the
fron
t
View
from
the
fron
t
View
from
abo
ve
View
from
abo
ve
(a)
View from the frontView from the front View from the leftView from the left
View from aboveView from above
(b)
Fig. 3.4 Relative positions of the three views and the symbol
!"1 2&'+3(*)+,(- *(2- %&4*)+/&- $,'+)+,('- ,.- /+&0'
An object positioned in space may be imagined as surrounded by six mutually perpendicular
planes. So, for any object, six different views may be obtained by viewing at it along the six
directions, normal to these planes. Figure 3.5 shows an object with six possible directions to
obtain the different views which are designated as follows:
1. View in the direction a = view from the front
2. View in the direction b = view from above
3. View in the direction c = view from the left
Vist
a Fr
onta
l
Vist
a S
uper
ior
Vist
a La
tera
l Es
que
rda
Projeções
III. PROJEÇÕES ORTOGRÁFICAS
!20
1o Diedro 3o Diedro
46 Machine Drawing
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b
f
d
a
c
e
4. View in the direction d = view from the right
5. View in the direction e = view from below
6. View in the direction f = view from the rear
Figure 3.6a shows the relative positions of the above
six views in the first angle projection and Fig.3.6b, the
distinguishing symbol of this method of projection. Figure
3.7 a shows the relative position of the views in the third
angle projection and Fig. 3.7b, the distinguishing symbol
of this method of projection.
NOTE A comparison of Figs. 3.6 and 3.7 reveals that
in both the methods of projection, the views are
identical in
shape and detail. Only their location with respect to the
view from the front is different.
e
d a c f
b
(a)
(b)
 
b
c a d f
e
(a)
(b)
Fig. 3.6 Relative positions of six views Fig. 3.7 Relative positions of six views
 in first angle projection in third angle projection
!"# $%&'('%)*%+* (,-*%./-0(
It is important to understand the significance of the position of the object relative to the planes
of projection. To get useful information about the object in the orthographic projections, the
object may be imagined to be positioned properly because of the following facts :
1. Any line on an object will show its true length, only when it is parallel to the plane of
projection.
2. Any surface of an object will appear in its true shape, only when it is parallel to the
plane of projection.
In the light of the above, it is necessary that the object is imagined to be positioned such
that its principal surfaces are parallel to the planes of projection.
Fig. 3.5 Designation of the views
Símbolo indicativo de 
Projeção no 1o Diedro
46 Machine Drawing
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b
f
d
a
c
e
4. View in the direction d = view from the right
5. View in the direction e = view from below
6. View in the direction f = view from the rear
Figure 3.6a shows the relative positions of the above
six views in the first angle projection and Fig.3.6b, the
distinguishing symbol of this method of projection. Figure
3.7 a shows the relative position of the views in the third
angle projection and Fig. 3.7b, the distinguishing symbol
of this method of projection.
NOTE A comparison of Figs. 3.6 and 3.7 reveals that
in both the methods of projection, the views are identical in
shape and detail. Only their location with respect to the
view from the front is different.
e
d a c f
b
(a)
(b)
 
b
c a d f
e
(a)
(b)
Fig. 3.6 Relative positions of six views Fig. 3.7 Relative positions of six views
 in first angle projection in third angle projection
!"# $%&'('%)*%+* (,-*%./-0(
It is important to understand the significance of the position of the object relative to the planes
of projection. To get useful information about the object in the orthographic projections, the
object may be imagined to be positioned properly because of the following facts :
1. Any line on an object will show its true length, only when it is parallel to the plane of
projection.
2. Any surface of an object will appear in its true shape, only when it is parallel to the
plane of projection.
In the light of the above, it is necessary that the object is imagined to be positioned such
that its principal surfaces are parallel to the planes of projection.
Fig. 3.5 Designation of the views
Símbolo indicativo de 
Projeção no 3o Diedro
Legenda: 
a. vista frontal; 
b. vista superior; 
c. vista lateral esquerda; 
d. vista lateral direita; 
e. vista inferior; 
f. vista de trás.
46 Machine Drawing
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b
f
d
a
c
e
4. View in the direction d = view from the right
5. View in the direction e = view from below
6. View in the direction f = view from the rear
Figure 3.6a shows the relative positions of the above
six views in the first angle projection and Fig.3.6b, the
distinguishing symbol of this method of projection. Figure
3.7 a shows the relative position of the views in the third
angle projection and Fig. 3.7b, the distinguishing symbol
of this method of projection.
NOTE A comparison of Figs. 3.6 and 3.7 reveals that
in both the methods of projection, the views are identical in
shape and detail. Only their location with respect to the
view from the front is different.
e
d a c f
b
(a)
(b)
 
b
c a d f
e
(a)
(b)
Fig. 3.6 Relative positions of six views Fig. 3.7 Relative positions of six views
 in first angle projection in third angle projection
!"# $%&'('%)*%+* (,-*%./-0(
It is important to understand the significance of the position of the object relative to the planes
of projection. To get useful information about the object in the orthographic projections, the
object may be imagined to be positioned properly because of the following facts :
1. Any line on an object will show its true length, only when it is parallel to the plane of
projection.
2. Any surface of an object will appear in its true shape, only when it is parallel to the
plane of projection.
In the light of the above, it is necessary that the object is imagined to be positioned such
that its principal surfaces are parallel to the planes of projection.
Fig. 3.5 Designation of the views
Representação das Vistas no 1o e 3o Diedros
III. PROJEÇÕES ORTOGRÁFICAS
!21
Considerações para escolha da posição 
do objeto
Uma linha aparecerá em tamanho real se for paralela ao plano de projeção; 
Uma superfície aparecerá em formato real se for paralela ao plano de 
projeção; 
Um objeto deve ser posicionado em relação aos planos de projeção de 
maneira que, se possível, suas principais superfícies sejam 
paralelas aos planos de projeção;
III. PROJEÇÕES ORTOGRÁFICAS
!22
Linhas invisíveis
Projetando um objeto poderão existir características não visíveis em 
relação ao plano de projeção; 
As características invisíveis do objeto são representadas por linhas 
tracejadas; Orthographic Projections 47
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LineNo line
Fig. 3.9 Representation of tangential
curved surfaces
!"#"$ %&''()*+&)(,
While obtaining the projection of an object on to any
principal plane of projection, certain features of the
object may not be visible. The invisible or hidden
features are represented by short dashes of medium
thickness. Figure 3.8 shows the application of hidden
lines in the projection of an object.
!"#"- ./01('*2/0345(,
Certain objects contain curved surfaces,
tangential to other curved surfaces. The
difficulty in representing the surfaces can be
overcome if the following rule is observed.
Wherever a tangential line drawn to the curved
surface becomes a projector, a line should be
drawn in the adjacent view. Figure 3.9 shows
the representation of certain curved surfaces,
tangential to other curved surfaces.
Certain objects manufactured by casting
technique, frequently contain corners filleted
and the edges rounded. When the radius of a rounded corner is greater than 3 mm and the
angle between the surfaces is more than 90°, no line is shown in the adjacent view. Figure 3.10
shows the application of the above principle.
(a)
Fillet
Corner
(b)
Fillet
Corner
Fig. 3.10 Representation of corners and fillets
If true projection is followed in drawing the view of an object containing fillets and
rounds; it will result in misleading impression. In conventional practice, fillets and rounds are
represented by lines called runouts. The runouts are terminated at the point of tangency
(Fig. 3.11).
!"6 27+7.89:;* :<* =97>2
For describing any object completely through its orthographic projections, it is important to
select a number of views. The number of views required to describe any object will depend
Fig. 3.8 Application of hidden linesRepresentação de características invisíveis 
na projeção do objeto com linhas tracejadas;
III. PROJEÇÕES ORTOGRÁFICAS
!23
Superfícies Curvas
Superfícies curvas tangentes a outras Superfícies curvas:
Quando uma linha do objeto é uma 
aresta(1) ou um quadrante(2), ela 
deve aparecer na vista adjacente; 
Orthographic Projections 47
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LineNo line
Fig. 3.9 Representation of tangential
curved surfaces
!"#"$ %&''()*+&)(,
While obtaining the projection of an object on to any
principal plane of projection,
certain features of the
object may not be visible. The invisible or hidden
features are represented by short dashes of medium
thickness. Figure 3.8 shows the application of hidden
lines in the projection of an object.
!"#"- ./01('*2/0345(,
Certain objects contain curved surfaces,
tangential to other curved surfaces. The
difficulty in representing the surfaces can be
overcome if the following rule is observed.
Wherever a tangential line drawn to the curved
surface becomes a projector, a line should be
drawn in the adjacent view. Figure 3.9 shows
the representation of certain curved surfaces,
tangential to other curved surfaces.
Certain objects manufactured by casting
technique, frequently contain corners filleted
and the edges rounded. When the radius of a rounded corner is greater than 3 mm and the
angle between the surfaces is more than 90°, no line is shown in the adjacent view. Figure 3.10
shows the application of the above principle.
(a)
Fillet
Corner
(b)
Fillet
Corner
Fig. 3.10 Representation of corners and fillets
If true projection is followed in drawing the view of an object containing fillets and
rounds; it will result in misleading impression. In conventional practice, fillets and rounds are
represented by lines called runouts. The runouts are terminated at the point of tangency
(Fig. 3.11).
!"6 27+7.89:;* :<* =97>2
For describing any object completely through its orthographic projections, it is important to
select a number of views. The number of views required to describe any object will depend
Fig. 3.8 Application of hidden lines
(2)(1)
Sem linha Linha
(1)
Peças com cantos e arestas arredondadas com 
raio de arredondamento maior que 3 mm e o 
ângulo de dobra maior que 90o não há linha na 
vista adjacente. 
Orthographic Projections 47
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
LineNo line
Fig. 3.9 Representation of tangential
curved surfaces
!"#"$ %&''()*+&)(,
While obtaining the projection of an object on to any
principal plane of projection, certain features of the
object may not be visible. The invisible or hidden
features are represented by short dashes of medium
thickness. Figure 3.8 shows the application of hidden
lines in the projection of an object.
!"#"- ./01('*2/0345(,
Certain objects contain curved surfaces,
tangential to other curved surfaces. The
difficulty in representing the surfaces can be
overcome if the following rule is observed.
Wherever a tangential line drawn to the curved
surface becomes a projector, a line should be
drawn in the adjacent view. Figure 3.9 shows
the representation of certain curved surfaces,
tangential to other curved surfaces.
Certain objects manufactured by casting
technique, frequently contain corners filleted
and the edges rounded. When the radius of a rounded corner is greater than 3 mm and the
angle between the surfaces is more than 90°, no line is shown in the adjacent view. Figure 3.10
shows the application of the above principle.
(a)
Fillet
Corner
(b)
Fillet
Corner
Fig. 3.10 Representation of corners and fillets
If true projection is followed in drawing the view of an object containing fillets and
rounds; it will result in misleading impression. In conventional practice, fillets and rounds are
represented by lines called runouts. The runouts are terminated at the point of tangency
(Fig. 3.11).
!"6 27+7.89:;* :<* =97>2
For describing any object completely through its orthographic projections, it is important to
select a number of views. The number of views required to describe any object will depend
Fig. 3.8 Application of hidden lines
Filete
Canto
Orthographic Projections 47
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
LineNo line
Fig. 3.9 Representation of tangential
curved surfaces
!"#"$ %&''()*+&)(,
While obtaining the projection of an object on to any
principal plane of projection, certain features of the
object may not be visible. The invisible or hidden
features are represented by short dashes of medium
thickness. Figure 3.8 shows the application of hidden
lines in the projection of an object.
!"#"- ./01('*2/0345(,
Certain objects contain curved surfaces,
tangential to other curved surfaces. The
difficulty in representing the surfaces can be
overcome if the following rule is observed.
Wherever a tangential line drawn to the curved
surface becomes a projector, a line should be
drawn in the adjacent view. Figure 3.9 shows
the representation of certain curved surfaces,
tangential to other curved surfaces.
Certain objects manufactured by casting
technique, frequently contain corners filleted
and the edges rounded. When the radius of a rounded corner is greater than 3 mm and the
angle between the surfaces is more than 90°, no line is shown in the adjacent view. Figure 3.10
shows the application of the above principle.
(a)
Fillet
Corner
(b)
Fillet
Corner
Fig. 3.10 Representation of corners and fillets
If true projection is followed in drawing the view of an object containing fillets and
rounds; it will result in misleading impression. In conventional practice, fillets and rounds are
represented by lines called runouts. The runouts are terminated at the point of tangency
(Fig. 3.11).
!"6 27+7.89:;* :<* =97>2
For describing any object completely through its orthographic projections, it is important to
select a number of views. The number of views required to describe any object will depend
Fig. 3.8 Application of hidden lines
Filete
Canto
III. PROJEÇÕES ORTOGRÁFICAS
!24
Filetes e arredondamentos
48 Machine Drawing
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
Tangent
point Fillet
Runout
upon the extent of complexity involved in it. The higher the
symmetry, the lesser the number of views required.
!"#"$ %&'()*'+,-./+*&01
Some objects with cylindrical, square or hexagonal features
or, plates of any size with any number of features in it may
be represented by a single view. In such cases, the diameter
of the cylinder, the side of the square, the side of the hexagon
or the thickness of the plate may be expressed by a note or
abbreviation. Square sections are indicated by light crossed
diagonal lines. Figure 3.12 shows some objects which may
be described by one-view drawings.
f
50
f
50
f
32
f
32
!
65
38
584616
180
(a)
M 20
2 HOLES,
DIA 20
3 THICK
R 12
R 18
35
100
(b)
R 3
0
Fig. 3.12 One view drawings
!"#"2 3+4()*'+,-./+*&01
Some objects which are symmetrical
about two axes may be represented
completely by two views Normally, the
largest face showing most of the details
of the object is selected for drawing the
view from the front. The shape of the
object then determines whether the
second view can be a view from above
or a side view. Figure 3.13 shows the
example of two-view drawings.
Fig. 3.11 Runouts
Fig. 3.13 Two view drawing
R 35
f 35
20
8
40
5
f 15
180
140
33
33
R 8
Ponto de 
tangência Filete
Arredondamento 
III. PROJEÇÕES ORTOGRÁFICAS
!25
Seleção das Vistas
Desenhos de uma única vista 
 Peças com seções, cilíndricas, hexagonais e quadradas podem ser 
representadas em uma vista única; 
Nesses casos, é fornecida a dimensão e um símbolo indicativo 
ou uma nota especificando a forma da seção; 
Peças de placa com qualquer quantidade de características podem 
ser representadas em uma vista única com uma nota especificando 
a espessura da placa
III. PROJEÇÕES ORTOGRÁFICAS
!26
Seleção das Vistas
Desenhos de uma única vista
48 Machine Drawing
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
Tangent
point Fillet
Runout
upon the extent of complexity involved in it. The higher the
symmetry, the lesser the number of views required.
!"#"$ %&'()*'+,-./+*&01
Some objects with cylindrical, square
or hexagonal features
or, plates of any size with any number of features in it may
be represented by a single view. In such cases, the diameter
of the cylinder, the side of the square, the side of the hexagon
or the thickness of the plate may be expressed by a note or
abbreviation. Square sections are indicated by light crossed
diagonal lines. Figure 3.12 shows some objects which may
be described by one-view drawings.
f
50
f
50
f
32
f
32
!
65
38
584616
180
(a)
M 20
2 HOLES,
DIA 20
3 THICK
R 12
R 18
35
100
(b)
R 3
0
Fig. 3.12 One view drawings
!"#"2 3+4()*'+,-./+*&01
Some objects which are symmetrical
about two axes may be represented
completely by two views Normally, the
largest face showing most of the details
of the object is selected for drawing the
view from the front. The shape of the
object then determines whether the
second view can be a view from above
or a side view. Figure 3.13 shows the
example of two-view drawings.
Fig. 3.11 Runouts
Fig. 3.13 Two view drawing
R 35
f 35
20
8
40
5
f 15
180
140
33
33
R 8
ESPESSURA	
  3
2	
  FUROS,	
  	
  
DIA	
  2O
Placa com espessura 3 mm e 
diversos furos e 
arredondamentos . 
Eixo com uma seção quadrada, seções 
cilíndricas e uma extremidade roscada. 
III. PROJEÇÕES ORTOGRÁFICAS
!27
Seleção das Vistas
Desenhos de 2 vistas 
 Peças simétricas em relação a 2 eixos podem ser representadas em 2 
vistas; 
Normalmente a maior face mostra o maior número de detalhes e 
é selecionada como a vista frontal; 
A forma do objeto vai determinar se a outra vista será uma vista 
superior ou uma vista lateral.
III. PROJEÇÕES ORTOGRÁFICAS
!28
Seleção das Vistas
Desenhos de 2 vistas
Desenho com 2 vistas: lembrando que não é 
aconselhável inserir cotas em arestas invisíveis. 
48 Machine Drawing
dharm
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Tangent
point Fillet
Runout
upon the extent of complexity involved in it. The higher the
symmetry, the lesser the number of views required.
!"#"$ %&'()*'+,-./+*&01
Some objects with cylindrical, square or hexagonal features
or, plates of any size with any number of features in it may
be represented by a single view. In such cases, the diameter
of the cylinder, the side of the square, the side of the hexagon
or the thickness of the plate may be expressed by a note or
abbreviation. Square sections are indicated by light crossed
diagonal lines. Figure 3.12 shows some objects which may
be described by one-view drawings.
f
50
f
50
f
32
f
32
!
65
38
584616
180
(a)
M 20
2 HOLES,
DIA 20
3 THICK
R 12
R 18
35
100
(b)
R 3
0
Fig. 3.12 One view drawings
!"#"2 3+4()*'+,-./+*&01
Some objects which are symmetrical
about two axes may be represented
completely by two views Normally, the
largest face showing most of the details
of the object is selected for drawing the
view from the front. The shape of the
object then determines whether the
second view can be a view from above
or a side view. Figure 3.13 shows the
example of two-view drawings.
Fig. 3.11 Runouts
Fig. 3.13 Two view drawing
R 35
f 35
20
8
40
5
f 15
180
140
33
33
R 8
III. PROJEÇÕES ORTOGRÁFICAS
!29
Seleção das Vistas
Desenhos de 3 vistas 
 Em geral a maioria dos objetos simples ou as montagens com várias 
partes, necessitam 3 vistas; 
Nesses casos, as vistas mais comumente utilizadas são a vista 
frontal, a vista superior e a vista lateral esquerda;
III. PROJEÇÕES ORTOGRÁFICAS
!30
Seleção das Vistas
Desenhos com 3 vistas no 1o diedro
Desenho com 3 vistas: vista frontal, 
vista superior e vista lateral esquerda. 
Observe as linhas invisíveis e as linhas 
de centro nas cavidades.
Orthographic Projections 49
dharm
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!"#"! $%&''()*'+,-&.+*/01
In general, most of the objects consisting of either a single component or an assembly of a
number of components, are described with the help of three views. In such cases, the views
normally selected are the views from the front, above and left or right side. Figure 3.14 shows
an object and its three necessary views.
(b)
20203535
25
10
10
60
10
35
45
(a)
70
10
15
1515
Fig. 3.14 Three view drawing
Orthographic Projections 49
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
!"#"! $%&''()*'+,-&.+*/01
In general, most of the objects consisting of either a single component or an assembly of a
number of components, are described with the help of three views. In such cases, the views
normally selected are the views from the front, above and left or right side. Figure 3.14 shows
an object and its three necessary views.
(b)
20203535
25
10
10
60
10
35
45
(a)
70
10
15
1515
Fig. 3.14 Three view drawingPerspectiva isométrica: a seta 
indica a direção da tomada da 
vista frontal.
III. PROJEÇÕES ORTOGRÁFICAS
!31
Seleção das Vistas
Rebatimento a partir de 2 vistas para obter a 3a vista
Sequência de traçado para o rebatimento: 
1. Desenhe as vistas frontal e superior; 
2. Trace as linhas de projeção para a direita da 
vista superior; 
3. Arbitre a distância, D a partir da vista 
frontal para posicionar a vista lateral a 
ser desenhada; 
4. Construir a linha de esquadria a 45 °; 
5. Desde os pontos de intersecção entre a linha de 
esquadria e as linhas de projeção, trace linhas de 
projeção verticais; 
6. Trace as linhas de projeção horizontal a partir da 
vista frontal para cruzar as linhas acima. A 
figura obtida juntando-se os pontos de 
intersecção na ordem é a vista lateral 
desejada.Traçado da vista lateral esquerdal.
50 Machine Drawing
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!"# $%&%'()*%+,- (.- */00/+1- &/%20
When two views of an object are given, the third view may be developed by the use of a mitre
line.
!"#"3 ,4-546789:58-8;<-=><?-@94A-8;<-B<@8C-@94A-8;<-8?4-D>=<6-=><?7
Construction (Fig. 3.15)
1. Draw the views from the front and above.
2. Draw the projection lines to the right of the view from above.
3. Decide the distance, D from the view from the front at which, the side view is to be
drawn.
4. Construct a mitre line at 45°.
5. From the points of intersection between the mitre line and the projection lines, draw
vertical projection lines.
6. Draw the horizontal projection lines from the view from the front to intersect the
above lines. The figure obtained by joining the points of intersection in the order is the required
view.
Figure 3.16 shows the steps to be followed in constructing the view from above of an
object, from the given views from the front and left.
NOTE These exercises are aimed at improving the practice in reading and developing
the imagination of the student.
D
Mitre
line
45°
(a)
(b)
D
45
°
Mitre
line
(a)
(b)
 Fig. 3.15 Construction of the view from the left Fig. 3.16 Construction of the view from above
!"E 0)FG/+1- ,H%- &/%20
The views of a given object must be positioned on the drawing sheet so as to give a good and
balanced appearance. Keeping in view, (i) number of views, (ii) scale and (iii) space between
Linha	
  de	
  
esquadria
III. PROJEÇÕES ORTOGRÁFICAS
!32
Seleção das Vistas
Rebatimento a partir de 2 vistas para obter a 3a vista
Traçado da vista superior.
50 Machine Drawing
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d:\N-Design\Des3-1.pm5 Seventh Print
!"# $%&%'()*%+,- (.- */00/+1- &/%20
When two views of an object are given, the third view may be developed by the use of a mitre
line.
!"#"3 ,4-546789:58-8;<-=><?-@94A-8;<-B<@8C-@94A-8;<-8?4-D>=<6-=><?7
Construction (Fig. 3.15)
1. Draw the views from the front and above.
2. Draw the projection lines to the right of the view from above.
3. Decide the distance, D from the view from the front at which, the side view is to be
drawn.
4. Construct a mitre line at 45°.
5. From the points of intersection between the mitre line and the projection lines, draw
vertical projection lines.
6. Draw the horizontal projection lines from the view from the front to intersect the
above lines. The figure obtained by joining the points of intersection in the order is the required
view.
Figure 3.16 shows the steps to be followed in constructing the view from above of an
object, from the given views from the front and left.
NOTE These exercises are aimed at improving the practice in reading and developing
the imagination of the student.
D
Mitre
line
45°
(a)
(b)
D
45
°
Mitre
line
(a)
(b)
 Fig. 3.15 Construction of the view from the left Fig. 3.16 Construction of the view from above
!"E 0)FG/+1- ,H%- &/%20
The views of a given object must be positioned on the drawing sheet so as to give a good and
balanced appearance. Keeping in view, (i) number of views, (ii) scale and (iii) space between
Linha	
  de	
  
esquadria	
  
III. PROJEÇÕES ORTOGRÁFICAS
!33
Exemplo 1
Orthographic Projections 51
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
the views, the draughtsman should decide about the placement of views on the drawing sheet.
Sufficient space between the views must be provided to facilitate placement of dimensions,
notes, etc., on the drawing without overcrowding.
!"#$ %&'()*%+
NOTE For all the examples given, the following may be noted: Figure a-Isometric projection
and Figure b-orthographic views. Arrow indicates the direction to obtain the view from the
front.
3.1 Figures 3.17 to 3.21 show the isometric views of machine components and their view from
the front, the view from above and the view from the right.
3.2 Figure 3.22 shows how to obtain the view from the front, the view from above and the view
from the left from the given isometric view of a machine component.
120
60 30
15
10
20
30
2 HOLES,
DIA 20
15
20
45
15
1060
35
15 1530
(a)
60
35
15 20 45 15
10 20
15
120
60 10
30
2 HOLES,
DIA 20
(b)
Fig. 3.17
Perspectiva isométrica: a seta 
indica a direção da tomada da 
vista frontal.
Desenho com 3 vistas no 1o diedro: vista frontal, 
vista superior e vista lateral direita. Observe as 
linhas invisíveis e as linhas de centro.
Orthographic Projections 51
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
the views, the draughtsman should decide about the placement of views on the drawing sheet.
Sufficient space between the views must be provided to facilitate placement of dimensions,
notes, etc., on the drawing without overcrowding.
!"#$ %&'()*%+
NOTE For all the examples given, the following may be noted: Figure a-Isometric projection
and Figure b-orthographic views. Arrow indicates the direction to obtain the view from the
front.
3.1 Figures 3.17 to 3.21 show the isometric views of machine components and their view from
the front, the view from above and the view from the right.
3.2 Figure 3.22 shows how to obtain the view from the front, the view from above and the view
from the left from the given isometric view of a machine component.
120
60 30
15
10
20
30
2 HOLES,
DIA 20
15
20
45
15
1060
35
15 1530
(a)
60
35
15 20 45 15
10 20
15
120
60 10
30
2 HOLES,
DIA 20
(b)
Fig. 3.17
2 FUROS 
DIA 20
III. PROJEÇÕES ORTOGRÁFICAS
!34
Exemplo 2
Perspectiva isométrica: a seta 
indica a direção da tomada da 
vista frontal.
Desenho com 3 vistas no 1o diedro: vista frontal, 
vista superior e vista lateral direita. Observe as 
linhas invisíveis e as linhas de centro.
52 Machine Drawing
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
12
15
16
16
40
75
70
100
64
30
60°
22
12
(a)
16 1632
16
12
75
60°
30
15 70
40
100
22
64
12
(b)
Fig. 3.18
12
12
16
60
12
12
f
16
40
f
16 20 20
R20
f16
(a)
12 1216
40
60
R
4 HOLES,
DIA 16
12
20
12
40
R
(b)
Fig. 3.19
52 Machine Drawing
dharm
d:\N-Design\Des3-1.pm5 Seventh Print
12
15
16
16
40
75
70
100
64
30
60°
22
12
(a)
16 1632
16
12
75
60°
30
15 70
40
100
22
64
12
(b)
Fig. 3.18
12
12
16
60
12
12
f
16
40
f
16 20 20
R20
f16
(a)
12 1216
40
60
R
4 HOLES,
DIA 16
12
20
12
40
R
(b)
Fig. 3.19
III. PROJEÇÕES ORTOGRÁFICAS
!35
III. EXERCÍCIOS DE APLICAÇÃO:
1. Quais são os elementos que devem ser considerados ao obter uma 
projeção? 
2. O que é uma projeção ortográfica? 
3. Quando é uma projeção de um objeto chamado uma projeção ortográfica? 
4. Explicar a projeção no 1o Diedro e indicar o símbolo a ser utilizado: 
5. Explicar a projeção no 3o Diedro e indicar o símbolo a ser utilizado: 
6. Liste as possíveis projeções ortográficas que podem ser obtidas de um 
objeto no espaço, especificando as suas posições relativas. 
7. O que é um desenho de uma vista e para que tipo de objetos estes podem 
ser usados? 
8. Qual é a base sobre a qual o número de pontos de vista necessários para um 
objeto é selecionado? 
9. Quais são os pontos a serem considerados ao definir as diferentes vistas 
para representar um objeto de um objeto?
II. NORMAS E CONVENÇÕES
Nomenclatura Tamanho (Altura x Comp) 
[mm]
A3x3 420x891
A3x4 420X1188
A4x3 297x630
A4x4 297x840
A4x5 297x1050
Formatos alongadosFormatos ISO Série A
Tamanho dos desenhos: o desenho deve ser realizado na menor folha possível que 
permita a necessária resolução e completa definição.
!36
II. NORMAS E CONVENÇÕES
Legenda: deve conter (pelo menos): 
✴ Título do desenho
✴ Número da folha
✴ Escala: pode haver vista e/ou detalhes em escalas diferentes;
✴ Projeção: Símbolo para indicar método de projeção; se não 
indicado é assumido o 1o diedro;
✴ Proprietário: do desenho ou nome da empresa;
✴ Rubricas do desenhista, do revisor e do responsável.
MATERIAL TOLERÂNCIA ACABAMENTODATANOME
DES
VER
APRO
TÍTULO PROPRIETÁRIO 
PROJEÇÃO
DESENHO NO 
Posição da legenda na folha de 
desenho.
!37
II. NORMAS E CONVENÇÕES
Margens 
e 
guias:
Espessura mínima: 
20 mm para A0 e A1 
10 mm para A2, A3 e A4
Borda
Marca de corte
Marca de referência métrica
Marca de centroEspaço do desenho
Marca de orientação
Margem
Grade de referência
Legenda
!38
II. NORMAS E CONVENÇÕES
Margens e guias: 
✴Marca de corte: quando a folha tem bordas maiores que o padrão; 
✴Marca de referência métrica: útil para visualização de microfilmes; 
✴Borda: limite do papel; pode ter sobre-medida para corte posterior; 
✴Marca de orientação: indica a orientação do desenho na mesa;
✴Espaço do desenho: área limitada pelas margens; 
✴Marca de centro: para facilitar o posicionamento do desenho para cópia e 
microfilmagem; 
✴Margem: limites da área de desenho; 
✴Legenda: informações detalhadas do desenho; 
✴Grade de referência: permite a localização de partes e detalhes do desenho; 
!39
Escalas: 
✴A escala do desenho deve ser indicada na legenda;
✴Se há partes ou detalhes em escala diferente, as escalas devem ser 
colocadas junto às mesmas.
Categoria Escalas recomendadas
Escalas de 
aumento
50:1 
5:1
30:1 
2:1
10:1
Real 1:1
Escalas de 
redução
1:2 
1:20 
1:200 
1:2000
1:5 
1:50 
1:500 
1:5000
1;10 
1:100 
1:1000 
1:10000
!40
II. NORMAS E CONVENÇÕES
Linhas: 
✴ Linhas de 
diferentes tipos e 
espessuras são 
utilizadas no 
desenho;
G1 Linhas de centro 
!41
II. NORMAS E CONVENÇÕES
Traço
longo-curto fina, 
grossa nas extremidades e 
mudança de direção
Linha Descrição Aplicação
Contínua grossa A1 - contornos visíveis
Contínua fina, reta ou 
curva
B1 Linhas imaginárias de interseção 
B2 Linhas de chamada e cotas 
B3 Linhas de projeção 
B4 Linhas de guia 
B5 Linhas de hachuras 
B6 Contornos de peças em posições limite 
B7 Pequenas linhas de centro
Contínua fina, à mão livre
Contínua fina, em zigue-
zague
C1 Limites de vistas parciais ou 
interrompidas e linhas de ruptura
D1 Linha de ruptura
Tracejada E1 Contornos invisíveis
Traço longo-traço curto 
fina
Traço longo-traço 
curto grossa
G1 Linhas de centro 
G2 Linhas de simetria 
G3 Linhas de trajetória
H1 Planos de corte
J1 Indicação de linhas e superfícies nas 
quais se aplica algum requisito
Traço longo-duplo traço 
curto fina
K1 Contorno de peças adjacentes 
K2 Posições alternativas ou estremas de peças 
móveis 
K3 Linhas centroidais
II. NORMAS E CONVENÇÕES
✴Linhas: Exemplos de utilização no desenho
G1 Linhas de centro 
Detalhe de um manípulo de acionamento
Detalhe de estrutura 
soldada.
!42
II. NORMAS E CONVENÇÕES
Espessura de Linhas: 
✴Na prática, 2 espessuras de linha são utlilizadas;
✴A espessura da linha grossa deve ser no mínimo o dobro da 
espessura da linha fina;
A espessura das linhas deve ser escolhida de acordo com o 
tamanho e o tipo do desenho dentro da segunte faixa: 0.18, 0.25, 
0.35, 0.5, 0.7, 1, 1.4 and 2 mm;
O espaço entre 2 linhas paralelas, inclusive de hachuras, deve ser 
maior que 0.7 mm.
!43
II. NORMAS E CONVENÇÕES
Linhas coincidentes: se 2 ou mais linhas coincidem, a 
prioridade de visualização é a seguinte:
✴ Contornos e arestas visíveis (Linha grossa contínua tipo A);
✴ Contornos e arestas invisíveis (Linha tracejada tipo E);
✴Planos de corte (Linha Traço longo-curto, fina, grossa nas 
extremidades e mudança de direção, tipo H);
✴Linhas de centro e de simetria (Traço longo-curto fina, tipo G),
✴Linhas centroidais (Traço longo-duplo traço curto fina, tipo K),
✴Linhas de projeção (Linha contínua fina, tipo B).
!44
II. NORMAS E CONVENÇÕES
Concordância 
de linhas: 
Instruções Certo Errado
Começa com um traço não com um 
espaço
Os traços interceptam-se sem um 
espaço entre eles.
Três traços interceptam-se em um 
ponto.
A continuação de uma linha/arco 
visível começa com um espaço.
Arcos invisíveis começam com um 
traço.
Pequenos arcos invisíveis podem der 
feitos com linha contínua.
Dois arcos tangentes invisíveis 
encontram-se no ponto de tangência..
!45
II. NORMAS E CONVENÇÕES
Linhas de 
centro e eixos: 
Instruções Certo Errado
Linhas de entro e eixos começam com o 
traço longo.
Dois eixos intersectam com 
traço longo.
Eixos se estendem para fora do contorno 
da peço com um traço longo.
!46
II. NORMAS E CONVENÇÕES
Linhas de referência(leader): é uma linha de referência a 
uma característica (dimensão, objeto, texto, etc.) .
A linha de referência deve terminar em: 
✴ (a) Ponto, se termintam dentro do contorno de um objeto;
✴ (b) Seta, de termina no contorno do objeto;
✴ (c) Sem seta ou ponto, se termina em uma cota.
!47
II. NORMAS E CONVENÇÕES
Letras: as letras devem proporcionar uma leitura precisa e terem dimensões e 
espaçamento adequado para cópia e microfilmagem.
!48
18 Machine Drawing
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!"# $%&&%'()*
The essential features of lettering on technical drawings are, legibility, uniformity and suitability
for microfilming and other photographic reproductions. In order to meet these requirements,
the characters are to be clearly distinguishable from each other in order to avoid any confusion
between them, even in the case of slight mutilations. The reproductions require the distance
between two adjacent lines or the space between letters to be at least equal to twice the line
thickness (Fig. 2.8). The line thickness for lower case and capital letters shall be the same in
order to facilitate lettering.
IS0 81 ejA
fR
d
h
a e
h
c
a
b
Fig. 2.8 Dimensions of lettering
!"#"+ ,-./01-201
The following specifications are given for the dimensions of letters and numerals:
(i) The height of capital letters is taken as the base of dimensioning (Tables 2.6 and 2.7).
(ii) The two standard ratios for d/h, 1/14 and 1/10 are the most economical, as they
result in a minimum number of line thicknesses.
(iii) The lettering may be inclined at 15° to the right, or may be vertical.
Table 2.6 Lettering A (d = h/14)
Characteristic Ratio Dimensions, (mm)
Lettering height h (14/14)h 2.5 3.5 5 7 10 14 20
(Height of capitals)
Height of lower-case letters c (10/14)h — 2.5 3.5 5 7 10 14
(without stem or tail)
Spacing between characters a (2/14)h 0.35 0.5 0.7 1 1.4 2 2.8
Minimum spacing of base lines b (20/14)h 3.5 5 7 10 14 20 28
Minimum spacing between words e (6/14)h 1.05 1.5 2.1 3 4.2 6 8.4
Thickness of lines d (1/14)h 0.18 0.25 0.35 0.5 0.7 1 1.4
NOTE The spacing between two characters may be reduced by half, if this gives a better viusal effect as
for example LA, TV; it then equals the line thickness.
18 Machine Drawing
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!"# $%&&%'()*
The essential features of lettering on technical drawings are, legibility, uniformity and suitability
for microfilming and other photographic reproductions. In order to meet these requirements,
the characters are to be clearly distinguishable from each other in order to avoid any confusion
between them, even in the case of slight mutilations. The reproductions require the distance
between two adjacent lines or the space between letters to be at least equal to twice the line
thickness (Fig. 2.8). The line thickness for lower case and capital letters shall be the same in
order to facilitate lettering.
IS0 81 ejA
fR
d
h
a e
h
c
a
b
Fig. 2.8 Dimensions of lettering
!"#"+ ,-./01-201
The following specifications are given for the dimensions of letters and numerals:
(i) The height of capital letters is taken as the base of dimensioning (Tables 2.6 and 2.7).
(ii) The two standard ratios for d/h, 1/14 and 1/10 are the most economical, as they
result in a minimum number of line thicknesses.
(iii) The lettering may be inclined at 15° to the right, or may be vertical.
Table 2.6 Lettering A (d = h/14)
Characteristic Ratio Dimensions, (mm)
Lettering height h (14/14)h 2.5 3.5 5 7 10 14 20
(Height of capitals)
Height of lower-case letters c (10/14)h — 2.5 3.5 5 7 10 14
(without stem or tail)
Spacing between characters a (2/14)h 0.35 0.5 0.7 1 1.4 2 2.8
Minimum spacing of base lines b (20/14)h 3.5 5 7 10 14 20 28
Minimum spacing between words e (6/14)h 1.05 1.5 2.1 3 4.2 6 8.4
Thickness of lines d (1/14)h 0.18 0.25 0.35 0.5 0.7 1 1.4
NOTE The spacing between two characters may be reduced by half, if this gives a better viusal effect as
for example LA, TV; it then equals the line thickness.
Característica
Altura da letra 
(altura das maiúsculas)
Altura das letras minúsculas 
(sem popa ou cauda)
Espaçamento entre caracteres 
Espaçamento mínimo entre linhas 
Espaçamento mínimo entre palavras
Espessura da linha
Proporção Dimensões [mm]
II. NORMAS E CONVENÇÕES
Letras inclinadas
!49
Principles of Drawing 19
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j
A BCDE F GH IJKLMN
OPQRS TUVWX Y Z
bc d e f gh k lmn o p
q r s t u v w x y z
[( ;"–=+× %& [(
0123 4 5 6 789 I V X 75°
c i
Fig. 2.9 Inclined lettering
Table 2.7 Lettering B (d = h/10)
Characteristic Ratio Dimensions, (mm)
Lettering height h (10/10)h 2.5 3.5 5 7 10 14 20
(Height of capitals)
Height of lower-case letters c (7/10)h — 2.5 3.5 5 7 10 14
(without stem or tail)
Spacing between characters
a (2/10)h 0.5 0.7 1 1.4 2 2.8 4
Minimum spacing of base lines b (14/10)h 3.5 5 7 10 14 20 28
Minimum spacing between words e (6/14)h 1.5 2.1 3 4.2 6 8.4 12
Thickness of lines d (1/10)h 0.25 0.35 0.5 0.7 1 1.4 2
Figures 2.9 and 2.10 show the specimen letters of type A, inclined and vertical and are
given only as a guide to illustrate the principles mentioned above.
!"# $%&'()*$
In order to show the inner details of a machine component, the object is imagined to be cut by
a cutting plane and the section is viewed after the removal of cut portion. Sections are made by
at cutting planes and are designated by capital letters and the direction of viewing is indicated
by arrow marks.
Principles of Drawing 19
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j
A BCDE F GH IJKLMN
OPQRS TUVWX Y Z
bc d e f gh k lmn o p
q r s t u v w x y z
[( ;"–=+× %& [(
0123 4 5 6 789 I V X 75°
c i
Fig. 2.9 Inclined lettering
Table 2.7 Lettering B (d = h/10)
Characteristic Ratio Dimensions, (mm)
Lettering height h (10/10)h 2.5 3.5 5 7 10 14 20
(Height of capitals)
Height of lower-case letters c (7/10)h — 2.5 3.5 5 7 10 14
(without stem or tail)
Spacing between characters a (2/10)h 0.5 0.7 1 1.4 2 2.8 4
Minimum spacing of base lines b (14/10)h 3.5 5 7 10 14 20 28
Minimum spacing between words e (6/14)h 1.5 2.1 3 4.2 6 8.4 12
Thickness of lines d (1/10)h 0.25 0.35 0.5 0.7 1 1.4 2
Figures 2.9 and 2.10 show the specimen letters of type A, inclined and vertical and are
given only as a guide to illustrate the principles mentioned above.
!"# $%&'()*$
In order to show the inner details of a machine component, the object is imagined to be cut by
a cutting plane and the section is viewed after the removal of cut portion. Sections are made by
at cutting planes and are designated by capital letters and the direction of viewing is indicated
by arrow marks.
Característica Proporção Dimensões [mm]
Altura da letra 
(altura das maiúsculas)
Altura das minúsculas 
(sem popa ou cauda)
Espaçamento entre caracteres 
Espaçamento mínimo entre linhas 
Espaçamento mínimo entre palavras
Espessura da linha
II. NORMAS E CONVENÇÕES
Seções: para mostrar detalhes interiores de um componente, ele é imaginado 
cortado por um plano de corte e a secção é vista removendo a porção cortada..
!50
As Seções são feitas por planos de corte que e são designados por letras 
maiúsculas e a direção de visualização é indicada por marcas de 
seta.
Principles of Drawing 21
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X – X
X X
(a) (b)
Fig. 2.12 Hatching of adjacent components
X
X
X – X
5050
 Fig. 2.13 Sectioning along two Fig. 2.14 Hatching interrupted
 parallel planes for dimensioning
!"#"! $%&&'()*+,-(./
The cutting plane(s) should be indicated by means of type H
line. The cutting plane should be identified by capital letters
and the direction of viewing should be indicated by arrows.
The section should be indicated by the relevant designation
(Fig. 2.15).
In principle, ribs, fasteners, shafts, spokes of wheels
and the like are not cut in longitudinal sections and therefore
should not be hatched (Fig. 2.16).
Figure 2.17 represents sectioning in two parallel planes
and Fig. 2.18, that of sectioning in three continuous planes.
Fig. 2.15 Cutting plane indicationIndicação do plano de corte
Principles of Drawing 21
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X – X
X X
(a) (b)
Fig. 2.12 Hatching of adjacent components
X
X
X – X
5050
 Fig. 2.13 Sectioning along two Fig. 2.14 Hatching interrupted
 parallel planes for dimensioning
!"#"! $%&&'()*+,-(./
The cutting plane(s) should be indicated by means of type H
line. The cutting plane should be identified by capital letters
and the direction of viewing should be indicated by arrows.
The section should be indicated by the relevant designation
(Fig. 2.15).
In principle, ribs, fasteners, shafts, spokes of wheels
and the like are not cut in longitudinal sections and therefore
should not be hatched (Fig. 2.16).
Figure 2.17 represents sectioning in two parallel planes
and Fig. 2.18, that of sectioning in three continuous planes.
Fig. 2.15 Cutting plane indication
2 planos de corte paralelos
II. NORMAS E CONVENÇÕES
Hachuras: utilizada para mostrar a área cortada. O padrão da hachura 
pode indicar o material da peça cortada.
!51
Principles of Drawing 21
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X – X
X X
(a) (b)
Fig. 2.12 Hatching of adjacent components
X
X
X – X
5050
 Fig. 2.13 Sectioning along two Fig. 2.14 Hatching interrupted
 parallel planes for dimensioning
!"#"! $%&&'()*+,-(./
The cutting plane(s) should be indicated by means of type H
line. The cutting plane should be identified by capital letters
and the direction of viewing should be indicated by arrows.
The section should be indicated by the relevant designation
(Fig. 2.15).
In principle, ribs, fasteners, shafts, spokes of wheels
and the like are not cut in longitudinal sections and therefore
should not be hatched (Fig. 2.16).
Figure 2.17 represents sectioning in two parallel planes
and Fig. 2.18, that of sectioning in three continuous planes.
Fig. 2.15 Cutting plane indication
(a)Hachura de componentes adjacentes. 
(b)O pino de travamento das peças não é cortado.
Principles of Drawing 21
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X – X
X X
(a) (b)
Fig. 2.12 Hatching of adjacent components
X
X
X – X
5050
 Fig. 2.13 Sectioning along two Fig. 2.14 Hatching interrupted
 parallel planes for dimensioning
!"#"! $%&&'()*+,-(./
The cutting plane(s) should be indicated by means of type H
line. The cutting plane should be identified by capital letters
and the direction of viewing should be indicated by arrows.
The section should be indicated by the relevant designation
(Fig. 2.15).
In principle, ribs, fasteners, shafts, spokes of wheels
and the like are not cut in longitudinal sections and therefore
should not be hatched (Fig. 2.16).
Figure 2.17 represents sectioning in two parallel planes
and Fig. 2.18, that of sectioning in three continuous planes.
Fig. 2.15 Cutting plane indication
Hachura interrompida para 
visualização da cota
20 Machine Drawing
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c
ABCDE FGH IJKLMN
OPQRSTUVW X Y Z
bc d e f gh k mnop
q r s t u v w x y z
[ ( " –=+× % & [(
0123 4 5 6 7 8 9 I V X
l
Fig. 2.10 Vertical lettering
!"#"$ %&'()*+,-./ -01('*.+2
Hatching is generally used to show areas of sections. The simplest form of hatching is generally
adequate for the purpose, and may be continuous thin lines (type B) at a convenient angle,
preferably 45°, to the principal outlines or lines of symmetry of the sections (Fig. 2.11).
Fig. 2.11 Preferred hatching angles
Separate areas of a section of the same component shall be hatched in an identical
manner. The hatching of adjacent components shall be carried out with different directions or
spacings (Fig 2.12 a). In case of large areas, the hatching may be limited to a zone, following
the contour of the hatched area (Fig. 2.12 b).
Where sections of the same part in parallel planes are shown side by side, the hatching
shall be identical, but may be off-set along the dividing line between the sections (Fig. 2.13).
Hatching should be interrupted when it is not possible to place inscriptions outside the hatched
area (Fig. 2.14).
ângulos preferenciais para hachuras.
II. NORMAS E CONVENÇÕES
Planos de corte: 
Deve ser indicado por meio de linha tipo H - traço longo-curto 
fina. 
Deve ser identificado por letras maiúsculas e a direção de 
visualização deve ser indicada por setas. 
A seção deve ser indicada pela denominação relevante. 
Em princípio,
nervuras, anéis, parafusos, eixos, raios de rodas 
e similares não são seccionados em cortes longitudinais. 
 O padrão da hachura pode indicar o material da peça cortada.
!52
II. NORMAS E CONVENÇÕES
Planos de corte: elementos não cortados.
!53
22 Machine Drawing
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(a) (b) (c)
(d) (e)
Fig. 2.16 Sections not to be hatched
A – A
A
A
X
X
X - X
Fig. 2.17 Fig. 2.18
22 Machine Drawing
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(a) (b) (c)
(d) (e)
Fig. 2.16 Sections not to be hatched
A – A
A
A
X
X
X - X
Fig. 2.17 Fig. 2.18
Parafuso
Pino
Rebite
Nervura longitudinal
Eixo
II. NORMAS E CONVENÇÕES
Planos de corte:
!54
22 Machine Drawing
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(a) (b) (c)
(d) (e)
Fig. 2.16 Sections not to be hatched
A – A
A
A
X
X
X - X
Fig. 2.17 Fig. 2.18
À esquerda 3 planos contínuos ; à direita, 2 planos paralelos
II. NORMAS E CONVENÇÕES
Planos de corte:
!55
Principles of Drawing 23
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Sectioning in two intersecting planes, in which one is shown revolved into plane of
projection, as shown in Fig. 2.19.
In case of parts of revolution, containing regularly spaced details that require to be
shown in section, but are not situated in the cutting plane; such details may be depicted by
rotating them into the cutting plane (Fig. 2.20).
!"#"$ %&'()'&*+(,+%&-('&*+.&/01(2
Cross sections may be revolved in the relevant view or removed. When revolved in the relevant
view, the outline of the section should be shown with continuous thin lines (Fig. 2.21). When
removed, the outline of the section should be drawn with continuous thick lines. The removed
section may be placed near to and connected with the view by a chain thin line (Fig. 2.22 a) or
in a different position and identified in the conventional manner, as shown in Fig. 2.22 b.
A
A
A–A X–X
X
X
 Fig. 2.19 Fig. 2.20
Fig. 2.21 Revolved section
A
A
A–A
(b)(a)
Fig. 2.22 Removed section
Seção com 2 planos que se 
intersectam sendo um deles 
coincidente com um dos 
planos de projeção
Principles of Drawing 23
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Sectioning in two intersecting planes, in which one is shown revolved into plane of
projection, as shown in Fig. 2.19.
In case of parts of revolution, containing regularly spaced details that require to be
shown in section, but are not situated in the cutting plane; such details may be depicted by
rotating them into the cutting plane (Fig. 2.20).
!"#"$ %&'()'&*+(,+%&-('&*+.&/01(2
Cross sections may be revolved in the relevant view or removed. When revolved in the relevant
view, the outline of the section should be shown with continuous thin lines (Fig. 2.21). When
removed, the outline of the section should be drawn with continuous thick lines. The removed
section may be placed near to and connected with the view by a chain thin line (Fig. 2.22 a) or
in a different position and identified in the conventional manner, as shown in Fig. 2.22 b.
A
A
A–A X–X
X
X
 Fig. 2.19 Fig. 2.20
Fig. 2.21 Revolved section
A
A
A–A
(b)(a)
Fig. 2.22 Removed section
Partes de peças de revolução contendo detalhes 
espaçados irregularmente e que necessitam ser 
mostradas na seção mas estão fora do plano de 
corte podem ser girados e incluídos no plano de 
corte 
II. NORMAS E CONVENÇÕES
Seções revolvidas ou removidas:
!56
Quando revolvidas na 
própria vista, o contorno da 
seção deve ser mostrado com 
linha fina contínua. 
Principles of Drawing 23
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Sectioning in two intersecting planes, in which one is shown revolved into plane of
projection, as shown in Fig. 2.19.
In case of parts of revolution, containing regularly spaced details that require to be
shown in section, but are not situated in the cutting plane; such details may be depicted by
rotating them into the cutting plane (Fig. 2.20).
!"#"$ %&'()'&*+(,+%&-('&*+.&/01(2
Cross sections may be revolved in the relevant view or removed. When revolved in the relevant
view, the outline of the section should be shown with continuous thin lines (Fig. 2.21). When
removed, the outline of the section should be drawn with continuous thick lines. The removed
section may be placed near to and connected with the view by a chain thin line (Fig. 2.22 a) or
in a different position and identified in the conventional manner, as shown in Fig. 2.22 b.
A
A
A–A X–X
X
X
 Fig. 2.19 Fig. 2.20
Fig. 2.21 Revolved section
A
A
A–A
(b)(a)
Fig. 2.22 Removed section
Principles of Drawing 23
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Sectioning in two intersecting planes, in which one is shown revolved into plane of
projection, as shown in Fig. 2.19.
In case of parts of revolution, containing regularly spaced details that require to be
shown in section, but are not situated in the cutting plane; such details may be depicted by
rotating them into the cutting plane (Fig. 2.20).
!"#"$ %&'()'&*+(,+%&-('&*+.&/01(2
Cross sections may be revolved in the relevant view or removed. When revolved in the relevant
view, the outline of the section should be shown with continuous thin lines (Fig. 2.21). When
removed, the outline of the section should be drawn with continuous thick lines. The removed
section may be placed near to and connected with the view by a chain thin line (Fig. 2.22 a) or
in a different position and identified in the conventional manner, as shown in Fig. 2.22 b.
A
A
A–A X–X
X
X
 Fig. 2.19 Fig. 2.20
Fig. 2.21 Revolved section
A
A
A–A
(b)(a)
Fig. 2.22 Removed sectionQuando removidas da vista, o contorno da seção deve ser 
mostrado com linha grossa contínua. Observar a indicação 
do plano de corte
II. NORMAS E CONVENÇÕES
Meio corte, corte parcial ou local e seções sucessivas:
!57
Meio corte.
24 Machine Drawing
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!"#"$ %&'()*+,-./0
Symmetrical parts may be drawn, half in plain view and half in
section (Fig 2.23).
!"#"1 2/,&')*+,-./0
A local section may be drawn if half or full
section is not convenient. The local break may
be shown by a continuous thin free hand line
(Fig. 2.24).
!"#"# 344&05+6+0-)/( )*7,,+88.9+)*+,-./08
Successive sections may be placed separately, with designations for both cutting planes and
sections (Fig. 2.25) or may be arranged below the cutting planes.
A
A
B
B
D
DC
C
A–A B–B C–C D–D
Fig. 2.25 Successive sections
!": ;<=>?=@A<=32) B?CB?*?=@3@A<=
Certain draughting conventions are used to represent materials in section and machine elements
in engineering drawings.
!":"D E&-+4.&'8
As a variety of materials are used for machine components in engineering applications, it is
preferable to have different conventions of section lining to differentiate between various
materials. The recommended conventions in use are shown in Fig.2.26.
!":"! E&,F.0+);/6G/0+0-8
When the drawing of a component in its true projection involves a lot of time, its convention
may be used to represent the actual component. Figure 2.27 shows typical examples of
conventional representaion of various machine components used in engineering drawing.
Fig. 2.24 Local section
Fig. 2.23 Half section Corte parcial ou corte local.
24 Machine Drawing
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!"#"$ %&'()*+,-./0
Symmetrical parts may be drawn, half in plain view and half in
section (Fig 2.23).
!"#"1 2/,&')*+,-./0
A local section may be drawn if half or full
section is not convenient. The local break may
be shown by a continuous thin free hand line
(Fig. 2.24).
!"#"#
344&05+6+0-)/( )*7,,+88.9+)*+,-./08
Successive sections may be placed separately, with designations for both cutting planes and
sections (Fig. 2.25) or may be arranged below the cutting planes.
A
A
B
B
D
DC
C
A–A B–B C–C D–D
Fig. 2.25 Successive sections
!": ;<=>?=@A<=32) B?CB?*?=@3@A<=
Certain draughting conventions are used to represent materials in section and machine elements
in engineering drawings.
!":"D E&-+4.&'8
As a variety of materials are used for machine components in engineering applications, it is
preferable to have different conventions of section lining to differentiate between various
materials. The recommended conventions in use are shown in Fig.2.26.
!":"! E&,F.0+);/6G/0+0-8
When the drawing of a component in its true projection involves a lot of time, its convention
may be used to represent the actual component. Figure 2.27 shows typical examples of
conventional representaion of various machine components used in engineering drawing.
Fig. 2.24 Local section
Fig. 2.23 Half section
24 Machine Drawing
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!"#"$ %&'()*+,-./0
Symmetrical parts may be drawn, half in plain view and half in
section (Fig 2.23).
!"#"1 2/,&')*+,-./0
A local section may be drawn if half or full
section is not convenient. The local break may
be shown by a continuous thin free hand line
(Fig. 2.24).
!"#"# 344&05+6+0-)/( )*7,,+88.9+)*+,-./08
Successive sections may be placed separately, with designations for both cutting planes and
sections (Fig. 2.25) or may be arranged below the cutting planes.
A
A
B
B
D
DC
C
A–A B–B C–C D–D
Fig. 2.25 Successive sections
!": ;<=>?=@A<=32) B?CB?*?=@3@A<=
Certain draughting conventions are used to represent materials in section and machine elements
in engineering drawings.
!":"D E&-+4.&'8
As a variety of materials are used for machine components in engineering applications, it is
preferable to have different conventions of section lining to differentiate between various
materials. The recommended conventions in use are shown in Fig.2.26.
!":"! E&,F.0+);/6G/0+0-8
When the drawing of a component in its true projection involves a lot of time, its convention
may be used to represent the actual component. Figure 2.27 shows typical examples of
conventional representaion of various machine components used in engineering drawing.
Fig. 2.24 Local section
Fig. 2.23 Half section
Seções 
Sucessivas.
II. NORMAS E CONVENÇÕES
Convenções 
de 
Hachura 
para 
materiais:
!58
Principles of Drawing 25
dharm
d:\N-Design\Des2-1.pm5 Seventh Print
Type Convention Material
Metals
Glass
Packing and
Insulating material
Liquids
Wood
Concrete
Steel, Cast Iron, Copper and its
Alloys, Aluminium and its Alloys,
etc.
Lead, Zinc, Tin, White-metal, etc.
Glass
Porcelain, Stoneware, Marble,
Slate, etc.
Asbestos, Fibre, Felt, Synthetic
resin products, Paper, Cork,
Linoleum, Rubber, Leather, Wax,
Insulating and Filling materials, etc.
Water, Oil, Petrol, Kerosene, etc.
Wood, Plywood, etc.
A mixture of Cement, Sand and
Gravel
Fig. 2.26 Conventional representation of materials
!"# $%&'()%*(%(+
A drawing of a component, in addition to providing complete shape description, must also
furnish information regarding the size description. These are provided through the distances
between the surfaces, location of holes, nature of surface finsih, type of material, etc. The
expression of these features on a drawing, using lines, symbols, figures and notes is called
dimensioning.
!"#", +-.-/0123/4.5461-7
Dimension is a numerical value expressed in appropriate units of measurment and indicated
on drawings, using lines, symbols, notes, etc., so that all features are completely defined.
Aço, Ferro fundido, Cobre e 
suas ligas, Alumínio e suas 
ligas, etc
Chumbo, Zinco, Estanho, Metal 
branco, etc
 Vidro
 Metais
 Tipo Convenção Material
 Vidro
 Material de 
embalagem e 
isolamento
Porcelana, Pedra, Mármore, etc. 
Asbestos, Fibras, Resinas 
sintéticas, cortiça, Borracha, 
Couro, Cera, material de 
Isolamento e Preenchimento, etc. 
II. NORMAS E CONVENÇÕES
Convenções 
de 
Hachura 
para 
materiais:
!59
Principles of Drawing 25
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Type Convention Material
Metals
Glass
Packing and
Insulating material
Liquids
Wood
Concrete
Steel, Cast Iron, Copper and its
Alloys, Aluminium and its Alloys,
etc.
Lead, Zinc, Tin, White-metal, etc.
Glass
Porcelain, Stoneware, Marble,
Slate, etc.
Asbestos, Fibre, Felt, Synthetic
resin products, Paper, Cork,
Linoleum, Rubber, Leather, Wax,
Insulating and Filling materials, etc.
Water, Oil, Petrol, Kerosene, etc.
Wood, Plywood, etc.
A mixture of Cement, Sand and
Gravel
Fig. 2.26 Conventional representation of materials
!"# $%&'()%*(%(+
A drawing of a component, in addition to providing complete shape description, must also
furnish information regarding the size description. These are provided through the distances
between the surfaces, location of holes, nature of surface finsih, type of material, etc. The
expression of these features on a drawing, using lines, symbols, figures and notes is called
dimensioning.
!"#", +-.-/0123/4.5461-7
Dimension is a numerical value expressed in appropriate units of measurment and indicated
on drawings, using lines, symbols, notes, etc., so that all features are completely defined.
 Tipo Convenção Material
 Líquido
 Madeira
 Concreto
 Água, Óleo, Petróleo, 
Querozene, etc.
 Madeira, compensado, etc.
 Mistura de cimento, areia e 
brita.
II. NORMAS E CONVENÇÕES
!60
26 Machine Drawing
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Fig. 2.27 Conventional representation of machine components (Contd.)
 Aplicação Desenho Representação
 Recartilhado 
reto
 Recartilhado 
losangular
 Segmento 
quadrado em 
um eixo
 Furos 
radialmente 
distribuídos 
em um flange
Convenções 
de 
Representação 
de 
componentes 
de máquinas:
II. NORMAS E CONVENÇÕES
!61
Convenções 
de 
Representação 
de 
componentes 
de máquinas:
26 Machine Drawing
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Fig. 2.27 Conventional representation of machine components (Contd.)
 Aplicação Desenho Representação
 Rolamentos
 Rosca 
externa 
(detalhes) 
 Rosca 
interna 
(detalhes) 
 Rosca 
interna e 
externa 
(montagem)
II. NORMAS E CONVENÇÕES
!62
Principles of Drawing 27
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Title Subject Convention
Splined
shafts
Interrupted
views
Semi-elliptic
leaf spring
Semi-elliptic
leaf spring
with eyes
Cylindrical
compression
spring
Cylindrical
tension
spring
Subject Convention DiagrammaticRepresentation
(b)
Fig. 2.27 Conventional representation of machine components (Contd.)
 Aplicação Desenho Representação
 Eixos 
ranhurados
Vistas 
interrompidas 
Mola plana 
semi elíptica
Mola plana 
semi elíptica 
com olhais de 
fixação
Convenções 
de 
Representação 
de 
componentes 
de máquinas:
Principles of Drawing 27
dharm
d:\N-Design\Des2-1.pm5 Seventh Print
Title Subject Convention
Splined
shafts
Interrupted
views
Semi-elliptic
leaf spring
Semi-elliptic
leaf spring
with eyes
Cylindrical
compression
spring
Cylindrical
tension
spring
Subject Convention DiagrammaticRepresentation
(b)
Fig. 2.27 Conventional representation of machine components (Contd.)
 Aplicação Desenho Representação
 Eixos 
ranhurados
Vistas 
interrompidas 
Mola plana 
semi elíptica
Mola plana 
semi elíptica 
com olhais de 
fixação
II. NORMAS E CONVENÇÕES
!63