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TitleWorkshop Technology
LanguageEnglish
File Size3.9 MB
Total Pages125
Table of Contents
                            Chapter_1
chapter_2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Chapter 7th
Chapter 8th
                        
Document Text Contents
Page 1

Learning Objectives
On completion of this unit a learner will be able to

• Describe ferrous metals , non-ferrous metals and non-metals

• Know the properties and uses of ferrous and non ferrous metals

• Know the safety precautions to be followed in a work shop

1.0 Introduction
Engineering materials are those which are extensively used in various

engineering applications such as used for construction of bridges, machine tools,
automobiles, locomotives, ships, space crafts and many more.Steel is extensively
used in construction of bridges.Iron is used for various machine tools.Aircrafts
have aluminium bodies.Large number of household ,industrial goods,electronics
goods are made using plastics like TV cabinets computer bodies & toys.

Classification of Engineering Materials

Engineering materials are basically classified into two groups namely metals
and non-metals, and their sub classification is given below.



Engineering Materials

1UNIT

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Automobile Engineering Technician2

Classification of Engineering Materials

Mechanical Properties of Metals

The mechanical properties that determine the behavior of metals under
applied forces. These properties are most important for the designing point of
view.

1. Strength : Ability of a material to resist loads without failure.

2. Tensile Strength : Ability of a material in tension to withstand stress
without failure.

3. Shear Strength : Ability of a material to withstand transverse loads
without fracture.

4. Elasticity : Property of material which enables it to regain its original
shape after deformation with in the elastic limit.

5. Stiffness : Property of material which enables it to resist deformation.

6. Plasticity : Ability of material to be deformed permanently without
fracture even after removal of force.

Engineering Materials

Metals Non Metals

Ferrous
metals

Non Ferrous
metals

Polymers Ceramics

Wrought iron,
Carbon Steels,
Alloy steels,
Cast Iron.

Al, Cu,
Sl, tin,
zn

Thermo
static plastics

Thermo
plastic

Phenol
formal

dehyde Refractoreis,
Abrasives,
glass, Cement
and concrete

PVC
Polythene,
Acrylic resins

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(3) Mitre Square : It is used for marking and testing 45o. It consists of a
steel blade fitted in a wooden or metal stock at an inclination of 45o with
horizontal.

Fig. 4.4 Mitre Square

(4) Marking Knife : All the dimensional lines marked with pencil are cut
with marking knife. It has a chisel edge at one end and sharp point at other end.
It is made of steel.

Fig. 4.5 Marking Knife

(5) Marking Guage : It is commonly used when absolute accuracy is
required. It has a stem with a sharp point pin at one end. It is used to cut line
along the grains and parallel to an edge. The distance can be adjusted by sliding
the stock.

Fig. 4.6 Marking Guage

(6) Divider : It has two pointed legs and hardened to prevent wear. It is
used for transferring dimensions and scribing curves or circles.

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Fig. 4.7 Divider

4.2 Cutting Tools
Cutting tools are used to cut the wood to approximate size. The following

cutting tools are used in carpentry.

(a) Saw or Hand Saw : The saw is most commonly used cutting tool in
wood working section. All saws used in wood work essentially consists of two
main parts - the blade which carries the cutting teeth and the handle used for
holding during the cutting operations to apply pressure. The classification of
saws is according to their teeth and the direction of grains of the wood to be cut.

Fig. 4.8 Hand Saw

The following types of saws are used in wood working.

(b) Rip Saw : Rip saw is used to cut the wood along the grains. The cutting
action starts from near the tip and gradually the whole length.

Fig. 4.9 Rip Saw

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Diamonds : Diamonds of less than gcm quality are crushed to produce
abrasive grains for making grinding wheels.

Artificial :

a) Silicon Carbide

b) Aluminium Oxide

(a) Silicon Carbide : It is manufactured from 56 parts of silica sand, 34
parts of powdered coke,2 parts of salt and 12 parts of saw dust in a along.

(b) Aluminium oxide : It is manufactured by heating mineral bauxite, a
hydrated aluminium oxide clay containing silica, iron oxide, titanium oxide mixed
with ground coke iron borings

8.5 Applications of Grinding
Applications of grinding include the grinding of external and internal

cylindrical grinding , tapered and formed surfaces, gear teeth, threads and other
using appropriate wheels.

Summary
1. Lathe operates on the principle that the excess metal is removed by

using a cutting tool which is fed in to a rotating work piece.

2. According to design and construction the lathes are classified as i)Speed
lathe ii)engine lathe iii) Tool room lathe iv)capston and turret lathe

3. Operations which are performed on the lathe are turning, facing
,taper turning ,drilling,boring and knurling

4. Grinding machine is used to finish the work piece to much higher accuracy
and is performed by means of a rotating abrasive wheel that acts as a
cutting tool.

5. Grinding wheel materials are two types ie natural and synthetic

Short Answer Type Questions
1. Explain the working principle of lathe

2. Name different lathe operations

3. Define knurling

4. Explain the principle of grinding

5. Name grinding wheel materials

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Long Answer Type Questions
1. Draw a neat sketch of lathe and name the parts

2. Explain about any four lathe operations

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