Workshop Practice-1

Introduction
#Workshop
▪ It is a place where manufacturing processes are done.
▪ The word manufacture first appeared in English in 1567 and is derived from
the Latin manu factus, meaning “made by hand.”
▪ Manufacturing involves turning raw materials into finished products to be used
for some purpose.
Input Processing
(men, materials, machinery, Output
infrastructure and money) (Goods and services)
Feedback
controller
▪ There should be four attributes of the manufactured products:
1) Effectively
2) Efficiently
3) Economically
4) Environmental friendly
▪ To getting effective, efficient, and economical products we should have:
1) The best combination of input parameters.
2) Our selection (materials and method) should be good.
3) Developing newer things.
4) Improving the existing system process of materials.
▪ Need of manufacturing products
1) To make goods for the service/ use of human beings.
2) To support the living and improve the living standards.
3) Need more resources to increase productivity.
# Different manufacturing processes:
(a) Casting Process [Molten metal poured into mould cavity and solidified in
order to get desire shape ]
(b) Forming Process [Rolling, Forging, Extrusion, Drawing and Deep drawing]
(c) Fabrication Process /Joining process [Welding joints, Mechanical joints,
Adhesive joints ]
(d) Material Removal Process [Turning, Milling, Grinding,Threading, Drilling,
Broaching, Planning, Shaping]
 Module-1
Basics of Engineering Materials
Matter

▪ Matter is anything which has mass and takes up space.

▪ Matter may be contain : Atoms, Protons and Molecules.

Engineering materials

▪ The substance which are useful in the field of engineering are called
Engineering materials.

▪ Engineering materials are used to designing and manufacturing the products

through the investigation the properties and performance of the materials.
Ceramic materials
 Difference between ferrous and non ferrous materials
Ferrous materials Non- Ferrous metals

As ferrous contains iron, it shows magnetic Non-ferrous metals don’t show any magnetic
feature feature which means it’s non-magnetic.

Ferrous metals are less resistant to corrosion Non-ferrous metals are more resistant to
corrosion

One special feature of ferrous metals is it One special feature of non-ferrous metals is
possesses high tensile strength and durability their malleability

Ferrous metals can be oxidized Non-ferrous metals cannot be oxidized

Contain iron as base metal Contain base metal other than iron

Example: Iron, steel and steel alloy Example: Aluminium, copper, gold, silver,
platinum etc.

They having relatively low cost They are costly metals

 PHYSICAL PROPERTIES OF MATERIALS
▪A physical property is any property that is measurable, whose value describes a
state of a physical system.
▪The changes in the physical properties of a system can be used to describe its
changes between momentary states.

▪Physical properties are often referred to as observation.

There are following properties of the materials:

1. Density:
❖ The density of a material is its mass per unit volume. Its unit is kg/m3. The
density of an element is determined by its atomic number and other factors, such
as atomic radius and atomic packing.

❖ The density of a material is a function of temperature. The general relationship is

that density decreases with increasing temperature.
 Cont…
MATERIALS DENSITY (kg/m3)
Gold 19,300
Silver 10,500
Copper 8970
Aluminum 2700
Iron 7860
Steels 6920-9130
Lead 11350
Magnesium 1745
Ceramics 2300–5500
Glasses 2400–2700
Plastics 900–2000
Wood 400–700
2. Melting Point:
❖ For a pure element, the melting point (Tm) is the temperature at which the
material transforms from solid to liquid state.
❖ The melting point of a metal depends on the energy required to separate its
atoms.
❖ The temperature range within which a component or structure is designed to
function is an important consideration in the selection of materials.
MATERIALS MELTING POINT (⁰C)
Gold 1063
Silver 961
Copper 1082
Aluminum 660
Iron 1537
Steels 1371-1532
Lead 327
Magnesium 650
Ceramics -
Glasses 580-1540
Plastics 110-330
Wood -
3. Specific Heat:
❖ A material’s specific heat is the energy required to raise the temperature of a unit
mass by 1 degree.

MATERIALS SPECIFIC HEAT (J/kg K)

Gold 129
Silver 712
Copper 385
Aluminum 900
Iron 460
Steels 500
Lead 130
Magnesium 1025
Ceramics 750-950
Glasses 500-850
Plastics 100-2000
Wood 2400-2800
4.Thermal Conductivity:
❖ Thermal conductivity indicates the rate at which heat flows within and through
a material.
❖ Metallically bonded materials (metals) generally have high thermal conductivity,
while ionically or covalently bonded materials (ceramics and plastics) have poor
conductivity. MATERIALS THERMAL CONDUCTIVITY (W/mK)
Gold 317
Silver 429
Copper 393
Aluminum 222
Iron 74
Steels 15-52
Lead 35
Magnesium 154
Ceramics 10-17
Glasses 0.6-1.7
Plastics 0.1-0.4
Wood 0.1-0.4
5.Thermal Expansion:
❖ The thermal expansion of materials can have several significant effects,
particularly the relative expansion or contraction of different materials in
assemblies such as electronic and computer components, glass-to-metal seals.
❖ Thermal expansion in conjunction with thermal conductivity plays the most
significant role in causing thermal stresses (due to temperature gradients), both
in manufactured components and in tools and dies, and moulds for casting
operations.
6. Electrical, Magnetic, and Optical Properties:
• Electrical conductivity and the dielectric properties of materials are important
not only in electrical equipment and machinery, but also in such manufacturing
processes as the magnetic-pulse forming of sheet metals, resistance welding,
and the electrical-discharge machining and electrochemical grinding of hard and
brittle materials.
• The units of electrical conductivity are mho/m or mho/ft, where mho is the
reverse of ohm, the unit of electrical resistance.
• The influence of the type of atomic bonding on the electrical conductivity of
materials is the same as that for thermal conductivity.
Dielectric Strength
❖ An electrically insulating material’s dielectric strength is the largest electric field
it can encounter without degrading or losing its insulating properties.
❖ This property is defined as the voltage required per unit distance for electrical
breakdown and has the units of V/m or V/ft.

Optical Properties

❖ Among various other properties, colour and opacity are particularly relevant to
polymers and glasses.

Piezoelectric Effect
❖ The piezoelectric effect (piezo from Greek, meaning “to press”) is exhibited by
what are called smart materials.
❖ Two basic behaviours are involved:
❖ (a) When subjected to an electric current, these materials undergo a reversible
change in shape.
❖ (b) when deformed by an external force, the materials emit a small electric
current.
Stress- strain diagram for mild steel
 Composite
• A composite material is a material consists of two or more different material
which are different in chemical composition, insoluble in each other and
macroscopically distinct, which are combined together give enhanced
properties as compare to each individual material.

•
MATRIX
+ REINFORCEMENT = COMPOSITE
Role of matrix:
1. Binds fibres together.
2. Support the overall structure.
3. Protects the composite from humidity, chemicals, etc.
4. Protects fibres from damage due to handling
Role of reinforcement:
1. Strengthening
2. Carry load.
CLASSIFICATION OF COMPOSITES
 Advantages of composite material
1. Taylor made properties
2. High strength to weight ratio
3. Good mechanical, thermal, electrical and chemical properties.
4. Low cost
5. Easily handling.
 Module-2 Fitting shop
#Introduction to Fitting
▪Manufacturing processes are broadly classified into four categories;

(i) Casting processes, (ii) Forming processes, (iii) Fabrication processes, and (iv)
Material removal processes.

▪In all these processes, components are produced with the help of either machines
or manual effort.

▪The attention of a fitter is required at various stages of manufacture starting from

marking to assembling and testing the finished goods.
▪Working on components with hand tools and instruments, mostly on work benches
is generally referred to as ‘Fitting work’.

▪"Fitting" is the assembling together of parts and removing metals to secure

the necessary fit, and may or may not be carried out at the bench.
▪ The hand operations in fitting shop include :
a) Measuring
b) Marking
c) holding
d) Cutting
e) Chipping
f) Sawing
g) Scraping
h) Drilling
i) Grinding
j) Filing
k) Internal threading (i.e. Tapping)
l) External threading (i.e. Dieing) etc. using hand tools or power operated portable tools.
▪ Measuring and inspection of components and maintenance of equipment is also considered as
important work of fitting shop technicians.
 Measuring and Marking Tools
1. Try square:
▪ It consists of blade and stock, blade is made of steel and stock is made of cast
iron and both are attached at 90°.
▪ These are used for scribing draw straight lines or marking right angles and also
to check the trueness or flatness of the surface.

Try square

2. Scriber and surface gauge: Scriber

• It is made up of high carbon steel and used for marking lines.
• It is a piece of hardened rod having a pointed needle on one or both side.
• It works like a pencil.
• It is used to draw parallel lines of desired length.
3. Punch:
a. Centre Punch :- It is used to mark the centre of holes to be drilled. It is bigger in
size and made of high carbon steel which is hardened and tempered. Its pointed
end is 90°.
b. Dot Punch :- It is used for marking dotted lines and made of high carbon steel.
The angle of pointed end is 60°.
4. Angle Plate:
▪ It is used for holding and supporting the jobs and is made up of cast iron.
5. V-Block:
▪ It is very useful tool used for marking and drilling. The job is hold with the help
of u-clamp. The job is placed in v-groove and screw of u-clamp is tightened and
the grip is firmly held. It is used for marking, centre drilling or drilling holes.
6. Steel rules:
▪ It is made up of stainless steel and available in the sizes of 6" to 24".
▪ It is marked in mm and inches.

7. Vernier calliper:
• These instruments are widely used for precision measurement of length,
thickness, depth and diameter(inside and outside). In metric unit, its least count
is 0.01, 0.02 or 0.05 mm, but least count of 0.02 mm are most common in use.
• The inches vernier caliper have a least count of 0.001 inch.
• It consists of two jaw, one is movable with small vernier head and the other is
fixed, a beam, main scale, a depth gauge bar.
8. Micrometer:
▪ It is used for measuring diameter or thickness of a job. It is more accurate
than vernier calliper.
▪ It consists of a u-shape frame with lock nut, ratchet stop, spindle, sline and
thimble, etc.
▪ It is available in inches as well as millimetres. The least count is generally 0.001"
or 0.0001" or 0.0 l mm or 0.05 mm.
9. Dial indicator:
▪ It is generally used to check the run out or ovality of jobs
10. Divider:
▪ It is made up of steel having two legs for making arcs, dividing a line or
distribute the dimensions.

11. Callipers:
▪ It is used to measure inside and outside diameter of a job or the dimension of the
job.
▪ These are of three types-
a) Inside calliper — To measure the inside dia.
b) Outside calliper- To measure the outside dia.
c) Jenny or odd leg caliper — Used to draw a parallel line about an axis or
perpendicular line.
 # Work Holding Tools
1. Bench Vice
• The bench vice is a device commonly used for holding the work pieces.
• When the vice handle is turned in a clockwise direction the moving jaw forces
the work against the fixed jaw.
• The greater the pressure applied to the handle, the tighter is the work held. The
body of the vice is made of cast iron.
• Hardened steel plates to ensure better gripping of the work are fixed on the faces
of the two jaws.
• Jaw caps made of soft material such as aluminium or galvanised iron (G.I) sheet
are used to protect finished surfaces of the work gripped in the vice.
• Vices are specified by the maximum width that can be held or the maximum
opening between the jaws, varying from 75 mm to 300 mm.
2. V-block with clamp
• The V-block is a rectangular or square block with a V-groove on one or both
sides, opposite to each other.
• The angle of the V is usually 90 o. V-block with a clamp is used to hold
cylindrical work securely, during marking of measurements or for measuring
operations.
Material: C.I or hardened steel.
Parallel Clamp
• It is a simple screw clamp with parallel jaws to hold small jobs for working on
them.
 3. C-Clamp
• This is used to hold work against an angle plate or V-block or any other surface,
when gripping is required. It is also known as G-clamp.
4. Hand vice:
▪ It is a very small vice used for gripping small job and is hand operated.
• These vices are often used to repair the key or lock.
• It consists of a flange/wing nut, a spring provided between two legs and jaws
which are adjusted by wing nut.
4. Leg vice:
▪ It is made of mild steel and the jaws are of cast steel.
▪ It is stronger and used for heavy work.
▪ These vices are used for the operation such as chipping or hammering and it
is tightly mounted on the bench.
5. Pin vice:
▪ It is used to hold the wire or small diameter rods.
▪ It consists of a handle and small chuck(made up of tool steel) which carries
three hardened steel jaws which are operated by rotating the handle.
▪ The pieces to be held is inserted between the jaw and the handle is rotated to
tightly grip in the chuck.
6.Pipe vice:
▪ For handling pipes and tubes, a special type of vice known as pipe vice is used
for the operation like threading, knurling or tapering etc.
▪ It is used to hold pipes for the operations discussed above.
 Cutting Tool
• The tools which are used to remove the unwanted material for getting the shape
are called cutting tools. It may be-
1) Hacksaw:
▪ It is a common tool used for cutting rods, bars, pipes, etc. It may be fixed or
adjustable type.
▪ Blade of the hacksaw is made of high carbon steel or high speed steel and
frame is made of mild steel.
▪ The purpose of adjustable frame is that the blade of different sizes can be fixed
on them.
• It consists of a metal frame fitted with a wooden handle, wing nut (for tightening the
blade), a clip or pin to grip the blade.
• The length of blade varies from 8" to 14", but generally 12" blade is used in fixed
frame.
• The thickness and width of blade is l mm and 1/2 ".
• Blades are classified as Forward cut and Backward cut.
2) File:
▪ It is a multi teeth tool and commonly used by a fitter to remove material by rubbing
it on the metal.

Classification based on shape and size:

i. Square file — It has a square cross section and generally used for filing square holes
in workpiece.
ii. Flat file — It consist a flat long body with a rectangular cross-section and used for
filing flat surfaces is also for making rectangular grooves.
• iii. Round file — It is of a circular shape and is used for filing round holes or
concave surfaces.
iv. Half round file — It has a semi-circular shape in which one face is flat and other face
is round/cylindrical.
• Round face is used for filling concave surfaces while flat face is used for filing flat
surfaces.
v. Triangular file — Each face of this file makes an angle of 60° with the
• face. It is used for making angular surfaces and grooves having an included
• angle of 60°.
vi. Knife edge file — This file is used for making sharp and deep grooves and for
filing the corners of workpiece.
#Classification of files on the basis of number of cuts:
▪ It is categorized as single and double cut.
▪ In single cut, the teeth are at an angle of 60° to the face and the other row of
teeth is added in opposite direction in double cut files.
# Classification based on teeth Files are classified according to their teeth
• The space between two teeth is known as pitch and it plays an important role in
selection of file.
• According to their pitch, files are classified as —
a. Rough file — 8 to 10 teeth/cm.
b. Bastard file — 12 teeth/cm.
c. Second cut file — 16 teeth/cm.
d. Smooth file — 20 to 24 teeth/cm.
e. Dead smooth file — 40 or more teeth/cm.
# Methods of filling
3) Chiesels:
• It is used for chipping the material from workpiece.
• It is classified mainly as hot and cold chisels and length varies from 6" to 8".
• Commonly used chisels are flat, cross cut, half round and diamond point chisels.
Cutting angle of chisels are:
i. For hard material — 70° to 75°
ii. For medium-hard material — 60°
iii. For soft material — 40°
 Striking Tool
1) Hammer
• A hammer is a most common and generally used striking tools in fitting
shop for the purpose of chipping, cutting, punching, etc. with the help of
chiesel.
• It is also used for other purposes like driving nails in the wood,
punching holes in sheet metal, setting and fitting (tightening) of joints,
driving of wedge and straightening of uneven surfaces and bending of
surfaces.
• It consist a iron body with wooden handle and the weight range is
0.25kg to 2 kg.
• A hammer has four parts like peen, eye, cheeks and face.
• The peen is rounded top part of hammer and when top part is of ball shape or
spherical then it is called ball peen hammer.
• Eye hole is usually oval or elliptical in cross section to accommodate the handle
made of wood.
# Types of hand hammer
a. Ball peen hammer
b. Straight peen hammer
c. Cross peen hammer

• If the shape of peen is ball or spherical then it is called a ball peen hammer and is
mostly used for general purposes, like laying out, riveting, chipping and forming.
• If the peen is parallel to the handle of hammer then it is termed as straight peen
hammer and generally preferred for smithy work for reveting.
2) Sledge hammer:
▪ It is straight peen, cross peen and double face type and weights between 3 to 8
kg.
3) Soft hammer
• It is classified as:
a. Raw hide
b. Mallet
c. Brass
d. Plastic
e. Hard rubber hammer
▪ Sheet metal workers use these light weight soft hammers for forming soft
metals.
▪ In machine shop and fitting shop, these hammers are used when it is required to
strike machined and finished parts during repair or assembling
 Drilling Tools
▪ The process and methods of making a round hole is called drilling and tool is called
drill.
▪ It is made up of high speed steel.
▪ The commonly used drilsl are twist drill and flat drill which are flat in shape at the
cutting edge and are the cheapest drills.
▪ These can be used only for drilling a hole of smaller depth.
▪ A twist drill is another form of drill which consists of a spiral flute.
▪ A standard twist drill or fluted twist drill are made of cobalt or high speed steel or
high carbon steels.
▪ The drill has two main parts:-
a. A cylindrical body with spiral flutes and
b. A shank which may be parallel or taper. Parallel shank drills are of smaller size (up to
13mm dia). The shank is held in drill chuck of the drilling machine. Drills with taper
shank have a tang at the end of shank.
.
• Threading Tools —Taps and Dies
• Threads are cut either on machine like lathe, special screw machines or with the
use of hand taps and threading dies.
• Hand taps are used for cutting internal threads in a drilled hole whereas external
thread on rods or pipes are cut with help of a die set.
Tap
• A tap is made from tool steels (of which the drilling are made) and has a toothed
body with flutes on the surface.
• Usually four flutes on a tap provide cutting edges and also remove chips.
• The square end of the shank is for receiving the tap wrench or handle to rotate
the tap.
• A tap is used for making internal threads.
• It is inserted into the face of the hole at right angle.
• In hand tapping, a set of three taps is used as shown in the figure. Tap have a
toothed body with a cylindrical shape.
• It also consists of a flute.
• The taps are available in a set of three namely taper, intermediate and plug tap
and during tapping they are used in the same order.
• The tap is held by tap holder and before tapping, a hole must be drilled to the
size of the root diameter of the thread.
• Before tapping, tap must be held at right angle to the plane of the work piece
.
 Threading dies

• Threading dies are used for cutting external threads on studs, rods and pipes or
on other cylindrical sections.

• A threading die is essentially a nut with its teeth hardened with flutes cut inside
it to give sharp cutting edges.

• Threads in a die are tapered slightly to help the tool to take an easy start.

• The die mounted in a die holder is called a stock.

• Two types of dies. The sectional or splitted die is the one which is used for
common threading operations on heavy jobs.
• The two split portions can be set to have different gaps between them by mean
of the set screw. The round split or button die is generally used on capstan or
turret lathes for cutting threads.

• This is also used for hand threading on light jobs.