Conventional representation

Machine Drawing Signs and symbols

1. ____3.2 CONVENTIONAL REPRESENTATION OF MATERIALS

Fig. 3.1 shows the conventions used for different materials.

Type

Material

Convention

Metals

Steel, cast iron, copper and its
alloys, aluminum and its alloys etc.

Y

Lead, zinc, tin, white-metal etc.

PR
ERSTER
ERA
ns
199%

Glass

Packing and insulating
materials

Porcelain, stoneware, marble etc,

Asbestos, fibre, felt, synthetic resin
products, paper, cork, linoleum,
rubber, leather, wax, insulating and

filling materials

a)

2. Water, ol, petrol, Kerosene etc.

Concrete

m

|

Fig. 3.1: Conventional representation ofmateriale
3.3 CONVENTIONAL BREAKS j

©

3. CONVENTIONAL REPRESENTATION OF COMMON MACHINE

COMPONENTS

Title ‘Actual Projectin/Section Conventional |
[Siotted Head e E)

DRAWN AT 45”
Radial Ribs S E
Serrated Shaft] > |
Splined Shaft

Ratchet and Pinion

Baring

ES

Boll bearing _ Roller bearing

Straight Kuriing |

Conta.

4. Knurling

Parts

Fig. 3.3 : Convention:

Below are given different conventions for pipe joints and valves.
sr. Name and figure Sr. |
No Now|

1. Socket =
ı | |

|

‘ |

| lil |
|

I

|

| Socket joint

5. Check valve

|
Î
i
|
|
|

Union

6. Tie | Figure Conventions

mm
a

External screw
theead

Internal screw

screw threat WHT,
A A

VON
aan

[Square on shoe

Holes on circular +
pitch

ig. 3.6 : Conventional representation of some common features
3.5 TYPES OF SECTIONS

(a) Full Section :

(b) Half Section

7. (©) Broken Section :

(4) Offset Section

Fig. 3.10

(e) Revolved Section and Removed evolved section
Section

8. (9 Webs In Section +

(8) Pulley in Section :

(9 Alligned Section :

9. 3.6. CONVENTIONAL REPRESENTATION OF GEARS

Title

Sper Bone

Bevel gear 1

Worm gear

Rock and Pinion gear

10. 3.7 CONVENTIONAL REPRESENTATION OF SPRINGS _

Tn Fig. 3.16, the conventional representations of some common springs such as compression
‘springs and tension springs are shown. ee
Description | Actual Projection ‘Convention

View Section

Compression spring.
| with circular section

Compression spring
with square section

Tension spring

=

Tig. 3.16 : Conventional representation of springs

Title Representation
View m Simplified

Semi-elliptic leaf spring
(multi-elliptic spring)

Semi-elliptic leaf spring with

T
i

eyelets or eyeholes i —
í

| Sori-eliptic leaf spring with |
centre band

11. { Semiaiptc iat sping with
| yates ana centre

|
|

Coutersunk

3. | Bored and recessed

Bored component

12. 7. [chamfered u 3
| | |
| |
| | _1
8. ET |
_{ _ |
| 9. [Filet offemate radius |
| | |
ee ie A. uf
= ie
==

S| =

‘Taper is defined as, the ratio of the difference in the directions of two sections of a cone to their
distance".

ie reper = LES

Taper = 2tan$

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