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CONTENTS

1.Safety Precautions2.Plumbing

2.1 Basic Connection Involving Pvc / Gi Pipes And Pipe Fittings

2.2 Preparation Of Pipe Line From A Water Tank To Wash Basin

2.3 Preparation Of Pipe Line From A Water Tank To Water Heater

2.4 preparation of pipe line from a water tank to washing machine

2.5 Viva Voce

3.Carpentry3.1Planning3.2 Dove tail joint

3.3 TeeLap Joint

3.4 Viva Voce.

4.WELDING

4.1Square butt joint

4.2 Lap Joint

4.3 Tee Fillet Joint

4.4 Viva Voce

5.Basic Machining

5.1 Turning, facing and chamfering

5.2 Taper Turning

5.3 Drilling

5.4 Viva voce

P.S.V.COLLEGE OF ENGG., & TECH - DEPARTMENT OF MECHANICA

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6.Sheet Metal Work

6.1 Rectangular Tray

6.2 Funnel

6.3 Winnowing Pan

6.4 Viva Voce

7. Study Of Centrifugal Pump

8. Study Of Refrigeration & Air Conditioner

9. Smithy

9.1 Making Round Rod Into Hexagonal Headed Bolt

9.2 Viva Voce

10 Foundry

10.1 Stepped cone pulley

10.2 Gear

10.3 Viva Voce

11.FITTING

11.1 Square Fitting

11.2 V-Fitting

11.3 Viva Voce


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1. SAFETY PRECAUTIONS

Definition of Workshop:

It is a place where human efforts, machines, materials and tools together manufacturethe products.

Safety Aspects:

The shop floor should be kept clean and free from dirt of any kind. Always wear tight fit clothing with tucked in. Never wear chapplas in the workshop. Always wear leather shoes. Do not wear watches, metallic bangles, neck chains and any ornaments while working in the

workshop.

Never operate the machines without taking prior permission. Always walk in the Aisle space provided in the workshop. Do not keep the tools at the edge of the table. All the tools should be handled with proper precautions. Tools which are not used should be kept proper places. Ensure sufficient lightning and ventilation to avoid accidents. Never carry any sharp tool in the pocket. Use safety devices like Apron, Goggles, Gloves, Shields and Tongs while welding. Do not spill the oil and grease. If it is spilled, it should be cleaned immediately to

avoid slipping.

Always operate machines at a safe distance. Use Scissors and Cutters properly while working with the sheet metal. Avoid unnecessary talking and discussions while working and concentrate on the work. Incase if you find any difficulty of any nature, report immediately to the workshop supervisor. Do not shift the speed gears while machine is functioning. Use coolant while machining and wherever necessary.


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2.PLUMBING

Introduction:

Plumbing also refers to a system of pipes and fixtures installed in a building for the distribution

of potable water and the removal of waste water. Plumbing is the skilled trade of working with pipes,

tubing and plumbing fixtures for drinking water systems and the drainage of waste. A plumber is

someone who installs or repairs piping systems, plumbing fixtures and equipment such as water heaters.

The plumbing industry is a basic and substantial part of every developed economy due to the need for

clean water, and proper collection and transport of wastes. In addition to the straight pipe or tubing,

many fittings are required in plumbing systems, such as valves, elbows, tees, and unions.

Plumbing Tools:

1. Pipe wrench2. Pipe vice3. Pipe cutter4. Die set5. Hack saw

1.Pipe wrench:The pipe wrench is an adjustable wrench used for turning soft iron pipes and fittings

with a rounded surface. The design of the adjustable jaw allows it to rock in the frame, such that any

forward pressure on the handle tends to pull the jaws tighter together. Teeth angled in the direction of

turn dig into the soft pipe.

2. Pipe vice:

The pipe vice is used to hold the pipes rigidly in position during thread cutting and fitting of

bends, valves, couplings etc. it consists of fixed jaw and movable jaw to hold the work piece and a

screw rod with handle is used for an adjustment. This vice is fixed on the work bench.

3. Pipe cutter:

A pipe cutter is a type of tool used by plumbers to cut pipe. Besides producing a clean cut, the

tool is often a faster and more convenient way of cutting pipe than using a hacksaw, although this

depends on the metal the pipe is made out of. There are two types of pipe cutters. Plastic tubing cutters,

which really look much like a pair of pruning shears, may be used for thinner pipes and tubes such as a

Sprinkler pipe. Then there is a pipe cutter with a sharp wheel and adjustable jaw grips for use on

thicker pipes. These are used by rotating it around the pipe and repeatedly tightening it until it.


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Pipe Vice


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4. Die set:

A die head is a threading die that is used in the high volume production of threaded components.

They may be used for either cutting a thread or rolling a thread. They may also be used for internal or

external thread cutting.

5. Hack saw:

A hacksaw is a fine-tooth saw with a blade under tension in a frame, used for cutting materials

such as metal. Hand-held hacksaws consist of a metal arch with a handle, usually a pistol grip, with

pins for attaching a narrow disposable blade. A screw or other mechanism is used to put the thin blade

under tension. The blade can mounted with the teeth facing toward or away from the handle, resulting

in cutting action on either the push or pull stroke.

Pipes & Pipe Fittings:

Pipes:Threaded pipe is often used in plumbing and pneumatic applications. Because pipe joints must

form a seal, the threaded portion is slightly conical rather than cylindrical. As a result, threaded pipe

requires specialized taps and dies. A modified form of the basic pipe thread shape is the Dry-Seal

thread. The Dry-Seal thread is formed so that during assembly, the tips of the male threads are slightly

crushed into the roots of the female threads, affecting, in theory, a liquid-tight fit.

The pipes may be made up of different types like Plastic pipe, Galvanized Iron (GI) pipe, Mild

steel pipe, Cast iron pipe, Copper pipe, Brass pipe, Lead pipe, Rubber pipe, Fiber pipe, Polythene pipe.

Pipe Fittings:

Fittings are used in pipe and plumbing systems to connect straight pipe or tubing sections, to

adapt to different sizes or shapes, and to regulate fluid flow.

a) Elbow:

A pipe fitting installed between two lengths of pipe or tube allowing a change of direction,

usually 90 or 45. The ends may be machined for butt welding, threaded. When the two ends differ in

size, it is called a reducing orreducer elbow.


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GATE VALVE


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b) Tee:

A tee is used to either combine or split a fluid flow. Most common are tees with the same inlet

and outlet sizes, but 'reducing' tees are available as well.

c) Cap:

A type of pipe fitting, often liquid or gas tight, which covers the end of a pipe. A cap has a

similar function to a plug.

d) Plug:

A plug closes off the end of a pipe. It is similar to a cap but it fits inside the fitting.

e) Nipple:

Short stub of pipe, usually threaded iron, A nipple is defined as being a short stub of pipe which

has two male ends. Nipple is commonly used for plumbing and hoses, and second as valves for funnels

and pipes.

f) Coupling:

A coupling connects two pipes to each other. If the material and size of the pipe are not the

same, the fitting may be called a 'reducing coupling' or reducer, or an adapter.

g) Union:

A union is similar to a coupling, except it is designed to allow quick and convenient

disconnection of pipes for maintenance or fixture replacement.

h) Valve:

A valve is a device that regulates the flow of a fluid (gases, fluidized solids, slurries, or liquids)

by opening, closing, or partially obstructing various passageways. Plumbing valves, such as taps for hot

and cold water are the most noticeable types of valves. Valves may be operated manually, either by a

hand wheel, lever or pedal.

i) Wrench:

A wrench or spanner is a tool used to provide a mechanical advantage in applying torque to turn

bolts, nuts or other items designed to interface with a wrench.


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j) Flange:

Flanges are largely used for pipe joints. Flange joint may be made with flanges which are castintegral with the pipes (or) loose flanges which are welded (or) screwed with pipes.

k) Bush:

It is a short sleeve like piece which is used to reduce the size of a threaded opening.

Applications of Plumbing

The major categories of plumbing systems or subsystems are:

Potable cold and hot water supply

Traps, drains, and vents Septic systems Rainwater, surface, and subsurface water drainage Fuel gas piping


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PLUMBING EXERCISES


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2.1 BASIC CONNECTION INVOLVING PVC / GI PIPES AND PIPE FITTINGS

Aim:To connect the PVC / GI pipe with pipe fittings like valves, bends and tap.

Fittings and Components Required:

1. Pipes of different length2. Gate valve3. Tap4. Elbows5. Reducer

Tools required:

Pipe wrench, Hack saw, Die set, Hammer, Screw driver, Measuring tape.

Sequence of Operation:

a) Selection of pipes.b) Threading of pipes.c) Connection of the pipes with the pipe fittings

Working Steps:

1. The required pipe connection layout is drawn.2. Two pipes of required lengths are taken and the ends are threaded using die set.3. The gate valve which is internally threadded is connected between two pipes. The other end

of the pipe is connected with the elbow which is also internally threaded.

4. A third pipe, with external threads is connected to the elbow for vertical extension.5. To this pipe another elbow is attached at the free end.6. The free end of the second elbow is connected with another pipe for horizontal extension.7. A reducer coupling, with internal threads is connected to the horizontal pipe.8. A tap is connected properly to the end of the reducer coupling.


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PIPE LAYOUT

Result:Hence the required connection is obtained using required pipes and pipe fittings.


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2.2 PREPARATION OF PIPE LINE FROM A WATER TANK TO WASH BASIN

Aim:To prepare a pipe line from a water tank to a wash basin.


1. Wash basin2. Gate valves3. Connecting pipes of different lengths.4. Flexible pipes for inlet and drain.5. Pipe fittings like tee-joint, elbow

Tools required:

Pipe wrench, Hack saw, Die set, Hammer and measuring tape.


a. Selection of pipes of required length.b. Threading the ends of pipes as required.c. Connection of the water tank to wash basin.

Working Steps:

1. Mark the location of wash basin and fix it properly2. Fix the tap on the wash basin in the required position properly3. Draw the pipeline sketch to connect the wash basin tap with the water tank.4. Connect the water tank and the wash basin tap using required length of pipes and pipe

fittings.

5. Fix the flow control valve near the wash basin tap and connect its outlet with the tapusing flexible pipe.

6. Fix the flexible drain pipe from the wash basin to the common drain outlet.


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PIPE CONNECTIONS FOR WASHBASIN

DOUBLE LINE DIAGRAM

SINGLE LINE DIAGRAM

Result:

Hence the pipeline to the wash basin from the water tank is made.


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2.3 PREPARATION OF PIPE LINE FROM A WATER TANK TO WATER HEATER

Aim:To prepare a pipe line from a water tank to water heater


1. Water heater2. Gate valves3. Connecting pipes of different lengths.4. Pipe fittings like tee-joint, elbow5. A tap6. Shower

Tools required:



a. Selection of pipes of required length.b. Threading the ends of pipes as required.c. Connection of the water tank to water heater.d. Connection of the water heater to tap and/or shower.

Working Steps:

1. Mark the location of water heater and draw the pipe line diagram.2. Fix the water heater in the required position using required number of clamps.3. Connect the water tank and the water heater using required length of pipes and pipe

fittings.4. Fix the flow control valve (gate valve) near the water heater and using a flexible pipe

connects the water heater inlet and control valve outlet.

5. Connect the outlet of the water heater with the shower or tap with proper pipe fitings.

.


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PIPE CONNECTIONS FOR WATERHEATER

DOUBLE LINE DIAGRAM

SINGLE LINE DIAGRAM

Result:

Hence the pipeline to a water heater from the water tank is made


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2.4 PREPARATION OF PIPE LINE FROM A WATER TANK TO WASHING MACHINE

Aim:

To prepare a pipe line from a water tank to washing machine


1. Washing Machine2. Gate valves3. Connecting pipes of different lengths.4. Flexible pipe for inlet and drain for washing machine.5. Pipe fittings like tee-joint, elbow, reducer and coupling.

Tools required:



a. Selection of pipes of required length.b. Threading the ends of pipes as required.c. Connection of the water tank to washing machine.

Working Steps:

1. Mark the location of water heater and the pipe line diagram is prepared accordingly.2. Connect the water tank and the washing machine using required length of pipes and pipe

fittings.

3. Fix the flow control valve near the washing machine.4. Connect the gate valve outlet and the washing machine inlet using a flexible pipe.5. Fix the flexible drain pipe from the washing machine to the common drain outlet.


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PIPE CONNECTIONS FOR WASHINGMACHINE

DOUBLE LINE DIAGRAM

SINGLE LINE DIAGRAM

Result:

Hence the pipeline to the washing machine from the water tank is made.


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2.5 VIVA VOCE

1. What is plumbing?2. What is the purpose of plumbing?3. What are the different types of pipes commonly used?4. State the different types of pipe fittings used.5. State the difference between the elbows and bend? Where are they recommended?6. State the purpose of die cast?7. What is the difference between union and coupling?8. What is the advantage of flange joint?9. In a piping connection, the number of bends should be kept to a minimum. Why?10.What is the difference between a gate and a tap?11.State the different types of gates commonly used.12.What is the instrument used to form the thread on the pipes.13.Name some holding tools used in plumbing.14.What are flexible pipes? What are their uses?


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3. CARPENTRY

Introduction:

A carpenter (builder) is a skilled craftsperson who performs carpentry. Carpenters work with

wood to construct, install and maintain buildings, furniture, and other objects. The work may involve

manual labor and work outdoors.

Types of wood:

The wood is generally classified into three types; Soft, Hard and Plywood

1.Soft wood: It has straight fibers and it is weak but easy to work. Example: Deodar, Kail, Chir2.Hard wood: It is closed structure, heavy in weight, dark in colour, more durable. It is difficult to work. Example: Teak, Sal, Mango, Maple, Oak.

3.Plywood: It has three layers i.e., Top face plys layer, Core layer and Bottom face plys layer. The top and bottom layers are called face plys layers. These two layers are bonded to the center core, which is

thick and not of good quality.

Wood Seasoning:

Wood Seasoning is the process of removal of moisture from Timber. This can also be termed as

the drying process of timber. Fresh timber has a very high quantity of moisture and hence is not useful

for use in construction or for manufacture of furniture. In the seasoning process the moisture of the

wood is brought down in the range of 8 - 15% based on the end application.

Following are the advantages of Seasoning:

1.No risk of fungal decay2.Reduces weight3.Improvement in Strength Properties4.Increase in Nail and screw holding capacity5.Improves Gluing capacity6.Helps in Preservative Treatment7.Wood exhibits better electrical and thermal Insulation properties


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C-Clamp


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BENCH VICE

MARKING GAUGE

METAL JACK PLANE


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Carpentry Tools:

1. A Ball Peen Hammer:

A ball-peen hammer is a type of peening hammer used in woodworking. It is distinguished from

a point-peen hammer or chisel-peen hammer by having a hemispherical head. Ball-peen hammers are

divided into two classes: hard-faced and soft-faced. The head of a hard-faced hammer is made of heat

treated forged high-carbon steel or alloy steel; it is harder than the face of a claw hammer. The soft-

faced hammers are made from brass, lead, tightly wound rawhide, or plastic. These hammers usually

have replaceable heads or faces, because they will deform, wear out, or break over time. They are used

when there is the danger of damaging a striking surface.

2. Mallet:

A mallet is a kind of hammer, made of wood, with a relatively large head. Wooden mallet,

usually used in carpentry to knock wooden pieces together or to drive dowels or chisels. A wooden

mallet will not deform the striking end of a metal tool, as most metal hammers would, but it also

reduces the force available to drive the cutting edge of a chisel.

3. Chisel:

They are particularly useful for cutting purpose with the help of mallet. It also has a

strengthening piece called a ferrule which prevents the handle from splitting at the bottom when it is hit

repeatedly by a mallet.

Types of Chisels

Chisels have a wide variety of uses. Many types of chisels have been devised, each speciallysuited to its intended use.

a) Mortise Chisel:

Thick, rigid blade with straight cutting edge and square sides to make mortises and similar

joints.

b) Dovetail Chisel:

Made specifically for cutting dovetail joints. The different being the thickness of the body of the

chisel, as well as the angle of the edges, permitting easier access to the joint.

c) Bevel Chisel:

Edged chisels are slightly undercut making them easy to push into corners. They are normally

used for finishing dovetail joints.


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d) Firmer Chisels:

They have a blade with a rectangular cross-section. This means that they are stronger and can be

used for tougher/heavier work.

4. Try square:

It is used for testing the flatness of the surfaces or whether the adjacent surfaces are at right

angles to each other or not.

5. Vice:

A vice is a mechanical screw apparatus used for holding or clamping a work piece to allow

work to be performed on it with tools such as saws, planes, drills, mills, screwdrivers, sandpaper, etc.

6. C- Clamp:

A C-clamp is a type of clamp device typically used to hold a wood or metal work piece, and are

often used in, but are not limited to, carpentry and welding. These clamps are called "C" clamps

because of their C shaped frame.

7. Saw:

A saw is used to cut the wood into pieces. It has different types as follows:

a) Mitre saw :

It is often referred to a large backsaw (20-30 inches or 60-90 cm) used either in a wooden mitre

box or in a metal frame which allowed cutting mitres of any specified angle.

b) Tenon saw:

It has a parallel blade of width 60 mm to 100 mm, length 250 mm to 400 mm and 12 to 20

points or teeth per 25 mm length. The teeth are shaped like a cross cut saw, in form of an equilateral

triangle.

c) Rip Saw:

It is used for cutting along the grains of wood. Its blade is about 700 mm long, and has 3 to 5

points or teeth per 25 mm length. The teeth of the rip saw have a series of chisel edge.

8. Steel Rule:

Steel rules, also called rulers, are essential for linear measurements in any shop. They can also

be used as guides for laying out lines, and if rigid enough, for cutting. The thinner, more flexible rules

can also be used to measure rounded or cambered work.


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9. Marking Gauge:

A marking gauge is used in woodworking and metalworking to mark out lines for cutting or

other operations. In metalworking it can be known as a scratch gauge. The purpose of the gauge is to

scribe a line parallel to a reference edge or surface. It is used in joinery and sheet metal operations.

10. Jack Plane:

It is used to make the surface of wood smooth to get good surface finish. A large range of planes

are available and they are used for different purposes. The body of a plane is made from high grade cast

iron with the cutters being tungsten made from vanadium steel. Mainly there are two types: Wooden

Jack Plane and Metal Jack Plane. Note that Metal Jack plane is used to get better surface finish.


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CARPENTRY EXERCISES


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3.1PLANNING

AIM:

To plane the given workpiece to the required shape and dimension.

Material Supplied:

Wooden piece of size 300x50x50 mm

Tools Required:

Steel rule, Marking Gauge, Try-Square, Carpentry Vice, Jack Plane and Tennon Saw


a) Rough Planningb) Markingc) Cutting (or) Sawingd) Finish planning

Working Steps:

1. The given job is checked to ensure its correct size.2.

The job is clamped rigidly in the carpentry vice and any two adjacent surfaces are planned usingjack plane to the given specifications.

3. Using try square the right angle of the work piece is checked.4. The required dimensions are marked on the job using steel rule and marking gauge.5. By means of Jack plane, the job is planned such that it should have accurate dimensions.6. The finished job is checked for right angle using try square and dimensions using steel rule.


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ALL DIMENSIONS ARE IN MM.

RESULT:

Hence the given work piece is planned to the desired shape and size.


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3.2 DOVE TAIL JOINT

AIM:

To make dovetail joint from the given workpiece to the required shape and dimension.

Material Supplied:


Tools Required:

Steel rule, Marking Gauge, Try-Square, Carpentry Vice, Jack Plane, Tennon Saw/ RibSaw, Mallet and Chisels


a. Rough Planningb. Markingc. Cutting (or) Sawingd. Chiselinge. Finish planning

Working Steps:

1. The given job is checked to ensure its correct size.2. The job is clamped rigidly in the carpentry vice and any two adjacent surfaces are planned using

jack plane to the given specifications.

3. Using try square the right angle of the work piece is checked.4. All the four sides are planned to get smoother and finished surfaces at right angles to each other.5. The job is cut into two halves using the Rib saw. Then proper marking is done for dovetail joint

on the two pieces using steel rule and marking gauge.

6. Using tennon saw and firmer chisel the unwanted portions are removed as per the drawing inboth the pieces.

7. The two pieces are assembled to check proper fitting..8. The finished job is checked for its accuracy using try square and steel rule.


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DOVETAIL JOINT


RESULT:

Hence the required dovetail joint is obtained from the given work piece


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3.3 TEELAP JOINT

AIM:

To make tee-lap joint from the given workpiece to the required shape and dimension.

Material Supplied:


Tools Required:

Steel rule, Marking Gauge, Try-Square, Carpentry Vice, Jack Plane, Tennon Saw, Rib Saw,Mallet and Chisels


a. Rough Planningb. Markingc. Cutting (or) Sawingd. Chisellinge. Finish planning

Working Steps:

1. The given job is checked to ensure its correct size.2. The job is clamped rigidly in the carpentry vice and any two adjecent surfaces are planned using

jack plane to the given specifications.

3. Using try square the right angle of the workpiece is checked.4. All the four sides are planned to get smoother and finished surfaces at right angles to each other.5. The job is cut into two halves using the Rib saw. Then proper marking is done for T-Lap joint

on the two pieces using steel rule and marking gauge.

6. Using tennon saw and firmer chisel the unwanted portions are removed as per the drawing inboth the pieces.

7. The two pieces are assembled to check proper fitting..The finished job is checked for its accuracy using try square and steel rule.


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TEE LAP JOINT


RESULT:

Hence the required Tee-lap joint is obtained from the given work piece


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3.4 VIVA VOCE

1) What is carpentry?2) Name few types of timbers and some examples for each type.3) What are the instruments used for measuring in carpentry?4) What are the different types of joints in carpentry?5) What is the use of try square?6) State the difference between mitre square and bevel square.7) What is the use of Calipers?8) How is the work piece held during working?9) What is setting of saw teeth?10)What are the different types of saw?11)What are different types of chisel?12)What is the difference between hammer and a mallet


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4. WELDINGIntroduction

Welding is a fabrication or sculptural process that joins materials, usually metals or

thermoplastics, by causing coalescence. This is often done by melting the work pieces and adding a

filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with

pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast

with soldering and brazing, which involve melting a lower-melting-point material between the work

pieces to form a bond between them, without melting the work pieces

Types of Welding:

The two types of welding most prevalently in use are

1. Arc welding 2. Gas Arc welding.

1.Gas weldingthe use of a combustible mixed with oxygen to create a flame for weldingis usedextensively in repair and maintenance work.

2 .Arc weldingthe use of a conductive arc to create heat and accomplish a weldis the most basic

and often used form of welding in industry.

Gas welding produces a wide, imprecise flame that can result in poor quality welds. In Arc

welding, an electric current creates an arc between a conductor called an electrode that is contained in

the welder's torch tip and the material to be welded. This arc generates the heat necessary to complete

the weld and gives the welder greater control over the welding process.

Welding Applications

Welding has traditionally been viewed as a heavy manufacturing process. The shipbuilding,

automobile manufacturing, construction and oil industries have benefited greatly from the expediency

of welding. These industrial applications still employ the majority of welding practices in use today.


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GASWELDING

SETUP


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ARC WELDING

From welding thick steel beams together to repairing the hulls of ocean tankers, welding is the

join technology of choice. Welding has also branched out into areas like electronics, aerospace, medical

device manufacture, instrumentation, and photonics. Welding is being used on rocket fuel tanks, glasssealing of electronic packages, nano-wire assemblies and glass to metal or silicon joining of sensors.

Today's welding processes involve plastic, glass, fiberglass, and ceramic in addition to metal.

GAS WELDING

Oxy Acetylene Welding Principle of Operation:

When acetylene is mixed with oxygen in correct proportions in the welding torch and ignited,

the flame resulting at the tip of the torch is sufficiently hot to melt and join the parent metal. The

oxyacetylene flame reaches a temperature of about 3200C and thus can melt all commercial metals

which, during welding, actually flow together to form a complete bond.

A filler metal rod is generally added to the molten metal pool to build up the seam slightly for

greater strength. Oxyacetylene welding does not require the components to be forced together under

pressure until the weld forms and solidifies.

Gas welding equipment:

The apparatus used in gas welding consists basically of an oxygen source and a fuel gas source

(usually cylinders), two pressure regulators and two flexible hoses (one of each for each cylinder), and

a torch. The cylinders are often carried in a special wheeled trolley.

1. Oxygen Cylinder:

Oxygen cylinder is usually painted in black colour. In this cylinder, oxygen is stored under a

pressure of 1550 N/m2.

The common cylinder is 1.8 m3,

3.5 m3,

7 m3,

etc.,

2. Acetylene Cylinder:

Acetylene cylinder is usually painted in maroon colour. In this cylinder, acetylene is storedunder a pressure of 175 N/m

2.The common cylinder is 1.6 m

3,2.8 m

3,8.4 m

3,etc.,

3. Regulator:

The regulator is used to control pressure from the tanks by reducing pressure and regulating

flow rate.


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4. Gas hoses:

The hose is usually a double-hose design, meaning that there are two hoses joined together. The

oxygen hose is green and the fuel hose is red. The type of gas the hose will be carrying is important

because the connections will have different threads for different types of gas. Fuel gases (red) will use

left-hand threads and a groove cut into the nut, while the oxygen (green) will use right-hand threads.This is a safety precaution to prevent hoses from being hooked up the wrong way.

5. Non-return valve:

Between the regulator and hose, and ideally between hose and torch on both oxygen and fuel

lines, a flashback arrestor and/or non-return valve should be installed to prevent flame or

Oxygen-fuel mixture being pushed back into either cylinder and damaging the equipment or

making a cylinder explodes.

6. Check valve:

A check valve lets gas flow in one direction only. A check valve is usually a chamber

containing a ball that is pressed against one end by a spring: gas flow one way pushes the ball out of the

way, and no flow or flow the other way lets the spring push the ball into the inlet, blocking it.

7. Torches:

The torch is the part that the welder holds and manipulates to make the weld. It has a connection

and valve for the fuel gas and a connection and valve for the oxygen, a handle for the welder to grasp, a

mixing chamber (set at an angle) where the fuel gas and oxygen mix, with a tip where the flame forms.

The top torch is a welding torch and the bottom is a cutting torch

a) Welding torch:

A welding torch head is used to weld metals. It can be identified by having only one or two

pipes running to the nozzle and no oxygen-blast trigger and two valve knobs at the bottom of the handle

letting the operator adjust the oxygen flow and fuel flow.

b) Cutting torch:

A cutting torch head is used to cut metal. It is similar to a welding torch, but can be identified by

having three pipes that go to a 90 degree nozzle and by the oxygen-blast trigger. Only iron and steel canbe cut using this method.


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8. Other Accessories:

a)Filler rod / Welding rod: Filler rod is a metal which is used in gas welding to supply additionalmetal to make the joint.

b)Flux is used in oxy-acetylene gas welding to prevent oxidation and also to remove impurities.The flux may be either in powder or liquid form.

9. Safety devices:

a)Goggles b) Leather goggles c) Apron

ARC WELDING

Principle of Operation:

In arc welding, the intense heat needed to melt metal is produced by an electric arc. The arc is

formed between the actual work and an electrode (stick or wire) that is manually or mechanically

guided along the joint. The electrode can either be a rod with the purpose of simply carrying the current

between the tip and the work. Or, it may be a specially prepared rod or wire that not only conducts the

current but also melts and supplies filler metal to the joint. Most welding in the manufacture of steel

products uses the second type of electrode.

An arc is created across the gap when the energized circuit and the electrode tip touches the

work piece and is withdrawn, yet still with in close contact. The arc produces a temperature of about

6000C at the tip. This heat melts both the base metal and the electrode, producing a pool of molten

metal sometimes called a "crater." The crater solidifies behind the electrode as it is moved along the

joint. The result is a fusion bond.

Arc Welding Equipment:

a) Power Supply:

The Main equipment used for electric arc welding is the transformer. It may be AC/ DC. Arc

welding may be done with direct current (DC) with the electrode either positive or negative or

alternating current (AC). The choice of current and polarity depends on the process, the type of

electrode, the arc atmosphere, and the metal being welded. The figure shows AC arc welding set upusing transformer. The transformer steps down the usual supply voltage (220 v to 440 v) to the open

circuit voltage required for the welding which is 40 v to 80 v.


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b) Electrode:

If an electrode is consumable, the tip melts under the heat of the arc and molten droplets are

detached and transported to the work through the arc column. This type of electrodes is made up of

steel, copper, brass bronze or aluminum.

If an electrode is non consumable, the tip of the electrode may not get melted. This type ofelectrodes is made up of carbon and graphite. Here filler rod has to be used.

c) Electrode Holder:

It is used to hold or secure the electrode. It should be light, strong and easy to handle. It allows

the shortest electrode possible to be used, ensuring rigidity and lack of deflection

d) Ground Clamp:

It is connected to the end of the ground cable and is clamped to the work or welding table to

complete the electric circuit.

e) Chipping Hammer:

It is chisel shaped one and it is used to remove slag from the weld beads.

f) Wire Brush:

It is used to clean the surface to be welded and it is also used to clean the weld.

g) Face Shield or Screen:

It is used to protect the eyes of the welder from the radiations. There are two types (i) Hand type

and (ii) Helmet type.

h) Goggles:

It is used to protect eyes of the welder from the light sparks produced during welding.

i) Hand Gloves:

It is used to protect the hands of the welder from the effect of ultra violet rays, infra red rays,

heat and sparks.


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WELDING EXERCISES


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4.1 SQUARE BUTT JOINT

Aim:

To join two given metal plates by a square butt joint using arc welding.

Material Supplied:

Mild Steel Plate of Size 75x50x6 mm

Tools required:

Power supply, (AC /DC), earthing clamp, welding electrode, welding torch, tongs, bench

vice, wire brush, gloves, shield, apron, safety goggles, steel rule, flat file, chipping hammer


a. Edge preparation (removal of rust, scale, etc)b. Tackingc. Weldingd. Coolinge. Chippingf. Cleaning

Working Steps:

1. The given metal plates are cleaned to remove rust and scale formation by using a wirebrush.

2. Then edge preparation is done to the required dimensions with the aid of bench vice and afile for a square butt joint.

3. Based on the thickness of the metal plates to be welded, the amperage and correct voltage isselected.

4. Two metal plates are placed as shown in the figure with a suitable gap of 2mm betweenthem and tag weld is done on the ends to avoid the movement of the plates while welding.

5. Then welding is started from one end of the plates and is continued till the other end bymaintaining 3 mm gap between the welding rod and the plates to be welded.

6. While welding goggles, gloves and shield are used for the safety of eyes and hand.7. The electric arc produced by the transformer melts the electrode and joins the two metal

plates.

8. Then cool the welded metal plates9. Finally the welded portion is chipped to remove slag using chipping hammer and wire

brush.


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SQUARE BUTT JOINT

ALL DIMENSIONS ARE IN MM

Result:

Hence the two given metal plates are joined by square butt joint using arc welding.


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4.2 LAP JOINT

Aim:To join two given metal plates by a lap joint using arc welding.

Tools required:

Power supply, (AC /DC), earthing clamps, welding electrode, welding torch, tongs, bench vice,

wire brush, gloves, shield, apron, safety goggles, steel rule, flat file and chipping hammer.

Material Supplied:




Working Steps:

1. The given metal plates are cleaned to remove rust and scale formation, by using a wire brush.2. Then edge preparation is done to the required dimensions, with the aid of bench vice.3. Based on the thickness of the metal plates to be welded the amperage and correct voltage

is selected.

4. Two metal plates are placed in the over lapped position using a support piece and tag weldis done on the ends to avoid the movement of the plates while welding.

5. Then welding is started from one end of the plates and is continued till the other end bymaintaining 3 mm gap between the welding rod and the plates to be welded.

6. While welding goggles, gloves and shield are used for the safety of eyes and hand.7. The electric arc produced by the transformer melts the electrode and joins the two

metal plates.

8. Then cool the welded metal plates9. Finally the welded portion is chipped to remove slag using chipping hammer and wire

brush.


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.

LAP JOINT


Result:Hence the two given metal plates are joined by lap joint using arc welding.


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4.3 TEE FILLET JOINT

Aim:To join two given metal plates, by T-fillet joint using arc welding.

Tools required:

Power supply, (AC /DC), earthing clamps, welding electrode, welding torch, tongs, bench vice,

Wire brush, gloves, shield, apron, safety goggles, steel rule, flat file and chipping hammer.

Material Supplied:




Working Steps:

1. The given metal plates are cleaned to remove rust and scale formation by using a wirebrush.

2. Then edge preparation is done to the required dimensions, with the aid of bench vice and afile to get perfect joint and good strength.

3. Based on the thickness of the metal plates to be welded, the amperage and correct voltage isselected.

4. One of the plates to be welded is kept at right angles to the surface of the other plate byusing tongs.

5. The tag weld is made on the ends to aviod the movement of the plates while welding.6. Then welding is started from one end of the plates and is continued till the other end on both

sides by maintaining a gap of 3mm between welding rod and the plates to be welded.

7. While welding goggles, gloves and shield are used for the safety of eyes and hand.8. The electric arc produced by the transformer melts the electrode and joins the two metal

plates.

9. Then cool the welded metal plates10.Finally the welded portion is chipped to remove slag using chipping hammer and wire

brush.


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TEE - JOINT


Result:

Hence the two given metal plates are joined by T-fillet joint using arc welding.


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4.4 VIVA VOCE

1) Define welding2) Say different types of welding.3) What is the temperature obtained in gas and arc welding?4) List the equipments needed to carry out welding operation.5) Which type of welding (Gas / Arc) you prefer/6) What are the necessary precautions you have to take while welding?7) Why you should not see the flame during the welding operation?8) What are the two gases used in gas welding?9) What are the different types of joints, you make in the lab?10)What is the difference between riveting and welding?11)What is gas welding?12)What is arc welding?13)What is electrode?14)Say the polarities of work piece and electrode?15)Name the material used for coating on electrode.16)Why flux is added during welding?17)How do welding is different from machining?18)How lap joint is performed?19)How butt joint is performed?20)Why tag weld is done during welding?


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5. BASIC MACHINING

LATHE

Introduction:

The lathe is an ancient tool, dating at least to the Egyptians and known and used in Assyria,

Greece, the Roman and Byzantine Empires. The origin of turning dates to around 1300BC when the

Egyptians first developed a two-person lathe. One person would turn the wood work piece with a rope

while the other used a sharp tool to cut shapes in the wood.

During the industrial revolution, mechanized power was applied to the lathe via steam engines

and line shafting, allowing faster and easier work. The design of lathes diverged between woodworking

and metalworking to a greater extent than in previous centuries. Metalworking lathes evolved into

heavier machines with thicker, more rigid parts. The application of lead screws, slide rests, and gearing

produced commercially practical screw-cutting lathes. Between the late 19th and mid 20th centuries,

individual electric motors at each lathe replaced line shafting as the power source. Beginning in the

1950s, servomechanisms were applied to the control of lathes and other machine tools via numerical

control (NC), which often was coupled with computers to yield computerized numerical control (CNC).

Today manually controlled and CNC lathes coexist in the manufacturing industries.

Working Principle:

In a lathe work piece is held and rotated about its axis. A cutting force is applied on the work

piece by a single point cutting tool and hence the material is removed from the work piece. The amount

of material removed from the work piece, in unit time is based on the depth of cut and feed. The single

point cutting tool used in a lathe is made up of High Speed Steel (HSS), cemented carbides and poly-

crystalline diamonds (PCD).

Parts of Lathe:

a) Lathe Bedb) Head stockc) Tail stockd) Carriage : (i) Apron (ii) Saddle (iii) Cross slide (iv) Compound rest (v) Tool poste) Feed rodf) Lead screw.


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.


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TURNING OPERATION

TAPER TURNING OPERATION


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a) Lathe Bed:

It is the base of the machine. On its left side, the head stock is mounted. The tail stock which is

moveable on the bed, mounted on the right side. The bed is made up of cast iron in order to resist the

vibrations occurring during the machining operations.

b) Head stock:

The head stock is permanently fastened on the inner ways at the left hand end of the bed. It

serves to support the spindle and driving arrangements. All lathes receive their power through the head

stock, which may be equipped with a step-cone pulleys or a geared head drive. The modern lathe is

provided with all-geared head stock to get large variation of spindle speeds.

c) Tail stock:

The tail stock is the counter part of the head stock and is situated at the right hand end of the

bed. It is used for supporting the work when turning on centers or when a long component is to be held

in a chuck. It is also used for holding and feeding the tools such as drills, reamers, taps, etc.,

d) Carriage:

In its simplest form the carriage holds the tool bit and moves it longitudinally (turning) or

perpendicularly (facing) under the control of the operator. The operator moves the carriage manually

via the hand wheelor automatically by engagingthe feed shaft with the carriage feed mechanism. This

provides some relief for the operator as the movement of the carriage becomes power assisted.

(i)Apron: It is fastened to the saddle and hangs over the front of the bed. It contains gears, clutches and

levers for operating the carriage by hand and power feeds. The apron had wheel can be turned to move

the carriage longitudinally back and forth by hand.

(ii)Saddle: It is an H-shaped casting that fits over the bed and slides along the ways between the head

stock and tail stock.

(iii)Cross slide: The cross-slide stands atop the carriage and has a feed screw that travels perpendicular

to the main spindle axis. This permits facingoperations to be performed, and the depth of cut to be

adjusted. This feed screw can be engaged, through a gear train, to the feed shaft to provide automated

'power feed' movement to the cross-slide. On most lathes, only one direction can be engaged at a time

as an interlockmechanism will shut out the second gear train.


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(iv)Compound rest: The compound rest (or top slide) is the part of the machine where the tool post is

mounted. It provides a smaller amount of movement along its axis via another feed screw. The

compound rest axis can be adjusted independently of the carriage or cross-slide. It is utilized when

turning tapers, to control depth of cut when screw cuts or precision facing, or to obtain finer feeds

(under manual control) than the feed shaft permits.

(v) Tool post: The tool bit is mounted in the tool post which may be of the American lanternstyle,

traditional 4 sided square style, or in a quick change style such as the multifix arrangement pictured.

The advantage of a quick change set-up is to allow an unlimited number of tools to be used (up to the

number of holders available) rather than being limited to 1 tool with the lantern style, or 3 to 4 tools

with the 4 sided type.

e)Feed rod: Feed rod is long shaft which gets power from the head stock spindle through largenumberof gears located in the feed box. It is used for the longitudinal movement of the carriage (or)

cross feed movement of the cross slide

f)Lead screw: A lead screw also known as a power screw or translation screw, is ascrewdesigned totranslate radial motion into motion. It is a long threaded shaft which is used during thread cutting

operations.

Lathe Operations

a)Turning: It is the operation of reducing the diameter of the work piece.b)Facing: It is the operation of reducing the length of the work piece.c)Chamfering: It is the operation of removing the sharp corners of the work piece to protect the edges of the job from getting damaged. It is done by keeping the tool at an angle of 45 degree to the lathe

axis.

d)Taper Turning: It is the operation of making uniform change in the diameter of the work piece along its length or producing conical surface on the work piece.

e)Drilling: It is the operation of making hole in the work piece. This can be achieved by fixing thedrill bit in tail stock and fed in to the rotating work piece.

f)Boring: It is operation of enlarging the already drilled hole.g)Knurling: It is the operation of making rough surface to get the get grip on the work piece.


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MACHINING EXERCISES


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5.1 TURNING, FACING AND CHAMFERING

Aim:

To make turning, facing and chamfering on the given metal work piece to get the requireddimension.

Material Supplied:

Mild Steel rod of 25 mm diameter x 75 mm length

Tools required:

Single point cutting tool, vernier caliper, steel rule, chuck key, tool post key, wire brush.


a. Checkingb. Work piece settingc. Tool settingd. Facinge. Turningf. Chamfering

Working Steps:

1. The given work piece is checked for its given dimensions.2. The work piece is held in the three jaw chuck. Chuck key is used to tighten the job rigi

ensuring centering of the work piece.

3. The single point cutting tool is fixed in the tool post of the lathe machine using tool post and spanners. Sometimes the packing material like hacksaw blade pieces, thick sheet pa

materials can be used to set the tool appropriately pointing towards the centre of the job.

4. Facing operation is done to obtain the required length of the job.5. Turning operation is done to obtain the required diameter of the job.6. Chamfering is done to remove sharp edges and corners of the work piece by keeping the too

an angle of 45 to the lathe axis.

7. Finally the work piece dimensions are checked to conform to the specification given in drawing.


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FACING, TURNING AND CHAMFERING

BEFORE MACHINING

AFTER MACHINING


Result:

Hence the required shape and size are obtained using turing, facing and chamfering operations othe given work piece.


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5.2 TAPER TURNING

Aim:

To make turning, facing and taper turning operations on the given metal work piece to getthe required dimension.

Materail Supplied:

Mild Steel rod of 25 mm diameter x 75 mm length

Tools required:

Single point cutting tool, vernier calipher, steel rule, chuck key, tool post key, wire brush andscribber.


a. Checkingb. Workpiece settingc. Tool settingd. Facinge. Turningf. Taper Turning

Working Steps:

1. The given work piece is checked for its given dimensions.2. The workpiece is held in the three jaw chuck. Chuck key is used to tighten the job rigidly,

ensuring centering of the workpiece.

3. The single point cutting tool is fixed in the tool post of the lathe machine using tool postkey. Sometimes the packing material like hacksaw blade pieces, thick sheet paper materials

can be used to set the tool appropriately pointing towards the centre of the job.

4. Facing operation is done to obtain the required length of the job.5. Turning operation is done to obtain the required diameter of the job.6. Next the taper turing operation is carried out as per the taper angle calculated using the

formula, tan = (D-d)/2L. Then compund rest base is swivelled and set at half taper angle.

Cutting tool is moved at set angle to the lathe axis by rotating the cross slide till the required

taper is obtained.

7. Finally the work piece dimensions are checked to conform to the specification given in thedrawing.


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TAPER TURNING

BEFORE MACHINING

AFTER MACHINING


Result:

Hence the required shape and size is obtained using turing, facing and taper turingoperations on the given work piece.


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5.3 DRILLING

Aim:

To drill holes on the given MS plate as per the specification given in the drawing.

Materail Supplied:

Mild Steel plate of 75x50x6 mm

Tools required:

Drilling Machine, Drill Bit, Drill chuck key, steel rule, wire brush, Dot Punch, Hammer, Flatfile.


a. Checkingb. Markingc. Workpiece settingd. Tool settinge. Drilling

Working Steps:

1. Mark the workpiece as per the specification given in the drawing.2. Holes centers are marked using dot punch and hammer.3. Keep the workpiece in the fixture.4. Bring the tool nearer the workpiece where it has to be drilled. This can be done

by adjusting the work table.

5. Perform drilling operation on the Workpiece.6. Repeat the process, till the required numbers of holes are drilled.7. Using the flat file remove the unwanted materials like burrs, chips etc.,8. Check the dimensions of the finished workpiece


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DRILLING


Result:

Hence the required shape and size is obtained using drilling operations on the given workpiece.


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5.4 VIVA VOCE

1) What do you mean by machining?2) Name the tools used in machining processes?3) List the parts of lathe?4) What are the operations can be performed on lathe?5) Why turning operation is done?6) Why facing operation is done?7) Give the formula for taper turning?8) Why chamfering is done?9) What is knurling?10)What is the material used for cutting tool and work piece in your lab?


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6.SHEET METAL

Introduction:

Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms

used in metalworking, and can be cut and bent into a variety of different shapes. Thicknesses can vary

significantly, although extremely thin thicknesses are considered foil or leaf, and pieces thicker than 6

mm (0.25 in) are considered plate. The thickness of the sheet metal is called its gauge. The gauge of

sheet metal ranges from 30 gauge to about 8 gauge. The higher the gauge, the thinner the metal is.

There are many different metals that can be made into sheet metal, such as: Aluminum, brass,

copper, steel, tin, nickel and titanium. For decorative uses, important sheet metals include silver, gold,

and platinum.

Sheet metal has applications in car bodies, airplane wings, medical tables, roofs for building and

many other things. Historically, an important use of sheet metal was in plate armor worn by cavalry,

and sheet metal continues to have many decorative uses, including in horse tack.

Specification of Sheet Metal:

The sheets specified by standard gauge numbers. Each gauge designates a definite thickness.

The gauge number can be identified by Standard Wire Gauge (S.W.G) .

S.W.G 10 12 14 16 18 20 22 24 26 30

Thickness3.2 2.6 2.0 1.6 1.2 0.9 0.7 0.6 0.4 0.3

(mm)

Sheet Metal Tools:

1. Cutting Tools2. Striking Tools3. Supporting Tools4. Marking and Measuring Tools5. Bending and Folding Tools6. Other Tools


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STRAIGHT SNIP CURVED SNIP

BENCH SHEAR

BALL PEEN HAMMER CROSS PEEN HAMMER

MALLET


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FLAT CHISEL

HALF ROUND CHISEL

BEAK HORN STAKE

HALF MOON STAKE FUNNEL STAKE


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1.Cutting Tools: (Chisels, Snips or Shears)a)Chisels:

This is used to cut the sheets. It is also used to remove the unwanted metal form the surface of a

job by chipping. Mostly flat type and round nose type chisels are used. Flat chisel are used to obtain flat

surface and its cutting edge is V-shape. Its cutting angle is 60 and the cutting edge varies from 20 to 25mm in width. But the cutting edge of the round nose chisel is round in shape and used for making

grooves. Its cutting angle varies from 35 to 40.

b) Snips (or) Shears:

The tool similar to scissors used for cutting or shearing thin metal sheets is called snip. Its

length varies from 200 mm to 600 mm. Mainly Straight Snip and Curved Snip is used. Bench shear is

used to cut the sheet metal of 3 mm thickness.

2. Striking Tools: (Hammersand Punches)

a) Hammers:

These are used on the sheet metal for straightening, bending, leveling, riveting, removing nails,

forging, chipping etc., with the application of impact load exerted manually. Mainly Ball peen hammer,

Cross peen hammers and Mallet used in practice.

b) Punch:

This is used for marking out work, locating centres etc. There are four types Dot punch Centre

punch, Letter punch and Number punch.

3. Supporting Tools: (Stakes, Anvils, Swage Block)

a) Stakes:

The stakes are used for doing various operations like forming, bending, hemming, seaming, etc.

There are different shapes of stakes available but based upon the purpose, the required shape of stake is

selected. They are Beak Horn stake, Funnel stake, Half moon stake etc.

b) Anvil:

The anvil acts as a base for smithy work while hammering. The body of the anvil is made ofmild steel (MS), wrought iron or cast iron (CI). The weight of the anvil varies from 100 to 150 kg.

c) Swage Block:

It is a CI block having number of slots of different shapes and sizes along its four side faces. It

also contains number of through holes of different size and shape from its top to bottom face. This


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BENCH PLATE

GROOVING TOOL

COMBINATION PLIERS PIPE PLIERS

DOT PUNCH


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block can be used for bending, punching and shaping of metals.

4. Marking and Measuring Tools: (Steelrule, Scriber, Trammel, Divider, Swing Blade Protractor,

Wire Gauge)

a)Steel rule: It is used for linear measurements up to the accuracy of 0.5 mm.b)Scribers: It is made up of hardened steel with pointed end used for marking lines on the sheet.c)Trammel (or) beam compass: It is a big size compass used for marking large arcs and circles.d)Divider: It is used for dividing straight and curvilinear lines, marking circles and arcs.e)Swing Blade Protractor: It is used for marking and measuring angles.f)Wire Gauge: It is used for measuring the thickness of sheet metal.

5. Bending and Folding Tools: (Pliers, Folding Bars)

a) Pliers:

The pliers are mainly used for bending the sheet metal to the required shape. It is also used for

holding and cutting the sheet metal. There are mainly two typesPipe pliers and Combination pliers.

b) Folding Bars:

The folding bars are used for bending and folding operation of the sheet metal.

6.Other Tools:a) Grooving Tools: It is used for making locked joints in sheets like wired edges, slots etc.b) Bench Plate: It is plate having the holes of different shapes and sizes.

Sheet Metal Operations:

1.Shearing: (Parting, Blanking, Punching, Notching, Slitting, Lancing, Trimming)2.Bending3.Drawing4.Squeezing1. Shearing Operation:

Shearing is a metalworking process which cuts stock without the formation of chips or the use

of burning or melting. Strictly speaking, if the cutting blades are straight the process is called Shearing;

if the cutting blades are curved then they are shearing-type operations.


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SOLID TYPE FOLDING BAR

SPLIT TYPE FOLDING BAR

WIRE GAUGE

SWING BLADE PROTRACTOR


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The most commonly sheared materials are in the form of sheet metal or plates, however rods can

also be sheared.

a)Parting: It signifies that scrap is removed between the two pieces to part them.b)Blanking: It means cutting a whole piece from sheet metal.c)Puching: It is the operation of producing circular holes on a sheet metal by punch and die.d)Notching: It is the process of removing the metal from the side or edge of a sheet.e)Slitting: It is the process of conducting shearing between the rotary blades.f)Lancing: It is the process of cutting sheet metal lengthwise.g)Trimming: It the process cutting away the excess metal in a flange or flash from a piece.2. Bending:

In this metal is stressed beyond the elastic limit, so that the metal is bent into right angle and

forming occurs when complete items or parts are shaped. It incorporates angle bending, roll bending,

and roll forming and seaming.

3. Drawing:

It is the process of producing cup shaped components from the sheet metal by required

number of punching strokes. It is done by placing the metal blank over a stationary die and exerting

required pressure from a punch against the blank.

4. Squeezing:

Squeezing is the one of the methods of forming ductile material. Riveting, cold heading

and rotary swaging are very common process of squeezing.

Sheet Metal Joints:

There are mainly two types: Hem and Seam

a)Hem: A hem is an edge or border made by folding. There are mainly three types of hem they are;(i)Single Hem: It is made by a single folding of the edge in the sheet metal to make it smooth &stiff.

(ii)Double Hem: The double hem is made by double folding of the edge in the sheet metal, to

make it smooth & stiff.

(iii)Wired Edge Hem: It is made by rolling the sheet metal to certain distance. This hem is

smooth and strong.

b)Seam: A seam is a joint made by fastening two edges of the sheet metal together.


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SPRING DIVIDER WING DIVIDER

TRAMMEL

DOUBLE POINT SCRIBER


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SHEET METAL EXERCISES


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6.1 RECTANGULAR TRAY

Aim:

To make the rectangular tray from the given sheet metal.

Material Required:26 gauge Galvanized Iron (G.I) Sheet [150x110mm]

Tools required:

Steel Rule, Scriber, Try-Square, Ball Peen Hammer, Mallet, Stacks, Straight Snip, Groover,Pliers and Compass.


a. Markingb. Cuttingc. Hemmingd. Bendinge. Finishing

Working Steps:

1. The given GI sheet is marked as per the given dimensions shown in the drawing.2. The unwanted portion of the sheet is cut by using the straight snip along the marked lines.3. Then the sheet is levelled for the perfect flatness using the mallet.4. The position of the hemming operation is marked at the edges with the help of the steel rule

and a scriber.

5. By holding the sheet in the bench vice the hemming operation is done on four sides of thetray using ball peen hammer.

6. The sides of the tray are bent to 90 degree as per the given sketch by using the requiredstacks, anvil and mallet.

7. Finally all the corners of the tray are joined by rivetting and finishing operations.


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DEVELOPMENT OF RECTANGULAR TRAY

RECTANGULAR TRAY


Result:

Hence the rectangular tray is made on the given GI sheet to the required size.


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6.2 FUNNEL

Aim:

To make the funnel from the given sheet metal.

Material Required:

26 gauge Galvanized Iron (G.I) Sheet [200x100mm]

Tools required:

Steel Rule, Scriber, Try-Square, Ball Peen Hammer, Mallet, Stacks, Straight Snip,Groover, Pliers and Compass.


a. Markingb.

Cutting

c. Hemmingd. Bendinge. Finishing

Formula Used:Angle , = (R/ L ) 360

Where , R = radius of the top circle of the funnel

L = Slanting lengthWorking Steps:

1. Funnel is splitted into cone and cylinder2. The development of cone and cylinder are drawn on the given GI sheet, using steel rule,

scriber and compass.

3. The unwanted portion of the sheet is cut by using the straight snip along the marked lines.4. Then the sheet is levelled for the perfect flatness using the mallet.5. The position of the hemming operation is marked at the top edge of the cone and also at the

bottom edge of the cylinder, with the help of the steel rule and a scriber as per the

specification given in the sketch.

6. The cone and the cylinder are joined together by seaming operation and soldering is donearound the joint.

7. Hemming is done at the top and bottom of the funnel by using required stacks and mallets8. Finally finishing operation is done to aviod ups and downs of the funnel


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DEVELOPMENT OF FUNNEL

CONE

NECK



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FUNNEL


Result:

Hence the funnel is made on the given GI sheet to the required size.


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6.3 WINNOWING PAN

Aim:

To make a winnowing pan from the given sheet metal.

Material Required:26 gauge Galvanized Iron (G.I) Sheet [130x110mm]

Tools required:

Steel Rule, Scriber, Try-Square, Ball Peen Hammer, Mallet, Stacks, Straight Snip,Groover, Pliers, Compass.


a. Markingb. Cuttingc.

Hemming

d. Bendinge. Finishing

Working Steps:

1. The given GI sheet is marked as per the dimensions shown in the drawing.2. The unwanted portion of the sheet is cut by using the straight snip along the marked lines.3. Then the sheet is leveled for the perfect flatness using the mallet.4. The position of the hemming operation is marked at the edges with the help of the steel

rule and a scriber.

5. Hemming is done at the top and bottom of the funnel by using required stacks and mallets.6. By holding the sheet in the bench vice, the hemming operation is done on the three sides of

the dust pan using ball peen hammer and pliers.

7. The sides of the dust pan are bent to 90 degree by using the required stacks anvil andmallet.

8. Finally all the corners of the tray are joined by riveting and finishing operations.


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DEVELOPMENT OF WINNOWING PAN

WINNOWING PAN


Result:

Hence the winnowing pan is made on the given GI sheet to the

required size.


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6.4 VIVA VOCE

1) Define sheet metal.2) What is the tool is used to measure the thickness of sheet metal?3) What do you mean by gauge?4) Name the various tools used in sheet metal5) What is the application of sheet metal?6) List the operation used in sheet metal.7) What are the metals used for sheet metal work?8) What is bending?9) What is punching?10)Why anvil is needed?


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7.CENTRIFUGAL PUMP

Introduction:

The centrifugal pump is a hydraulic machine which converts the mechanical energy into

hydraulic energy in the form of pressure energy, by means of the centrifugal force of a rotating element,

known as impeller.

The components of the centrifugal pump are:

1. Suction Pipe:

The pipe whose one end is connected to the inlet of the pump and the other end is below the

water surface in the sump is known as Suction pipe. A foot valve (a non return valve) is fitted at the

lower end of the suction pipe. The length of the suction pipe should be maintained as low as possible

and the number bends along the pipeline should be kept to a minimum.

2. Impeller:

The rotating part of the centrifugal pump is known as impeller. It has curved vanes arranged on

it. The impeller is mounted on a shaft, which is powered by an electric motor.

3. Casing:

Casing is an air tight passage surrounding the impeller. The casing has a gradual decrease in

cross sectional area, so that kinetic energy may be converted into pressure energy. The different types

of casings are,

A) Volute casing:

This is spiral in nature and facilitates the conversion of kinetic energy into pressure energy, by

the gradual decrease in cross sectional area. For larger pumps the increase in efficiency is not very

large, because of formation of eddies. Because of formation of eddies in the flowing water,

considerable energy is lost.

B) Vortex casing:

Here, a circular chamber is introduced between the impeller and the casing, to reduce the

formation of eddies. Thus loss of energy is prevented and as such the pumps have better efficiency.

C) Diffuser casing:

Here, the impeller is surrounded by a diffuser. The diffuser has a series of guide vanes. The

function of the diffuser is to transmit the water without shock. Hence the vibration of the pump is

reduced. The presence of diffuser decreases the area of cross section, which helps in reducing the flow,

consequently enhancing the pressure of the water.


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4. Delivery pipe:

A pipe whose one end is connected to the outlet of the pump and the other end to the delivery

tank is known as the delivery pipe.

Working principle:

The centrifugal pump works on the principle ofForced Vortex Flow, according to which, if a

certain mass of the fluid is rotated by an external torque, the rise in pressure head of the rotating liquid

takes place. The rise in pressure head at any point of the rotating liquid is proportional to the square of

tangential velocity of the liquid at that point.

Thus at outlet of the impeller where radius is more, the rise in pressure head will be more. This

increase in pressure head is responsible for raising the fluid to high level.

Types of impeller:

The different types of impellers are

A) Open impeller:

An open impeller is characterized by impeller blades that are supported almost entirely by the

impeller hub. This is the simplest impeller style and it is primarily applied to clean, non-abrasive, low

horsepower applications.

B) Closed impeller

A closed impeller incorporates a full front and back shroud. Fluid flows through the internal

impeller passages without hydraulic interaction with the stationary casing walls. In a well designed

enclosed impeller, the relative velocity between the impeller and the fluid at any given radius is quite

small. This results in less wear than other impeller styles.

C) Semi open impeller:

A semi-open impeller is a compromise between an open and an enclosed impeller. It

incorporates a single shroud, usually located on the back of the impeller. A semi-open impeller has a

solids passing capability similar to that found in an open impeller. With only a single shroud a semi-

open impeller is easy to manufacture and completely accessible for applying surface hardening

treatments. For moderately abrasive slurries, especially if plugging is a concern, a semi-open impeller is

a good choice.


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Priming of Centrifugal pump:

Before starting the pump, the air from suction pipe, impeller, casing and a part of the delivery

pipe are is removed and replaced by water. This operation is known as Priming.

If priming operation is not done, then the torque of the impeller will not be transmitter to the

water, due to lack of contact, and as such water will not rise in the deliver pipe.

Applications

1) It is used to fill the overhead tank, in houses and offices.2) In agricultural sector centrifugal pumps is used to deliver the water from the well.3) Large size centrifugal pump are used in industries.4) Centrifugal pumps play an important role in marine engineering, chemical engineering

and other fields of engineering also.

5) Centrifugal pumps are utilized to feed water to boilers in industries.


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8.AIR CONDITIONER

Introduction:

Air conditioner is a device used to condition the air according to human comfort. Air is

consisting of humidity, temperature, dust etc. The presence of these constituents makes the people to

feel discomfort and reduces the efficiency of persons. Therefore air has to be conditioner depending

upon the requirement. Generally in coastal areas the humidity level is more hence wet air prevails, so

air has to be dehumidified using air conditioner. In the tropical areas dry air prevails hence air has to be

humidified using air conditioner. Thus air conditioner may be classified according to season as Summer

Air Conditioner & Winter Air Conditioner.

Types of Air Conditioner:

1. Window Air Conditioner2. Spilt type Air Conditioner

WINDOW AIR CONDITIONER:

Working Principle:

The refrigerant vapour at high pressure and temperature is supplied by the compressor to the

condenser. A propeller type fan is used to draw air from atmosphere and to circulate through the

condenser coil. The air cools the refrigerant vapour and it becomes liquid.

Refrigeration cycle

The refrigeration cycle consists of the following processes .

1) Condensing coil 2) Expansion valve, 3) Evaporator coil, 4) Compressor.

Initially, a heat pump transfers heat from a lower-temperature heat source into a higher-

temperature heat sink. Heat would naturally flow in the opposite direction. This is the most

common type of air conditioning. A refrigerator works in much the same way, as it pumps the heat

out of the interior and into the room in which it stands.


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The most common refrigeration cycle uses an electric motor to drive a compressor. Since

evaporation occurs when heat is absorbed, and condensation occurs when heat is released, air

conditioners use a compressor to cause pressure changes between two compartments, and actively

condense and pump a refrigerant around. A refrigerant is pumped into the cooled compartment (the

evaporator coil), where the low pressure causes the refrigerant to evaporate into a vapor, taking heatwith it. In the other compartment (the condenser), the refrigerant vapor is compressed and forced

through another heat exchange coil, condensing into a liquid, rejecting the heat previously absorbed

from the cooled space. Air conditioning equipment usually reduces the humidity of the air processed by

the system and hence produces the effect.

COMPONENTS:

The refrigeration systems consists of :

a) Compressor

The compressor used in window air conditioner is of hermetic type. The refrigerant vapour

is compressed to high pressure and temperature in the condenser.

b) Air-cooled condenser

It is used to cool the high pressure high temperature refrigerant vapour. It is continuous coil

made of copper tubing. A propeller type fan is used to draw the necessary air from atmosphere to

cool the refrigerant.

c) Capillary tube

It is an expansion device. It is used to reduce the pressure and temperature of the refrigerant.

d) Evaporator

It is cooling coil made of copper. A centrifugal blower is installed behind the coil to deliver

cool air from the evaporator to the room. The blower also sucks warm air from the room and sends it to

the evaporator through a Filter.

Applications:

1) Used in offices, hotels, buses, cars, aero planes for human comfort.2) Used in textile industries to control moisture.3) Used in printing press, food industries, chemical plants etc.,

Window air conditioner is also known as room air conditioner, and is usually fitted in the window orany opening made in the wall of suitable dimensions. This is then packed with insulating material like

thermo coal to achieve better efficiency.


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SPLIT TYPE AIR CONDITONER:

Introduction:

Split air conditioners are used for rooms and halls, usually in places where window air

conditioners cannot be installed. However, these days many people prefer split air conditioner units

even for places where window air conditioners can be fitted.

The split type room air conditioner is comprised of two parts.

1) The outdoor unit,The outdoor unit, fitted outside the room, houses components like the

compressor, condenser and expansion valve.

2) The indoor unit.The indoor unit comprises the evaporator or cooling coil and the cooling fan. The split air

conditioner can be used to cool one or two rooms.

OUTDOOR UNIT :

This unit houses important components of the air conditioner like the compressor, condenser

coil and also the expansion coil or capillary tubing. This unit is installed outside the room or office

space which is to be cooled.

It consists of the following parts :

a) Compressor is the main component of the system and is used to compress the refrigerant.b) Condenser Coil is used to reject heat from the refrigerant to the out side air. c) Condenser Fan is used in air-cooled condenser to help move the air molecules over the surface

of the condensing coil, hence rejecting the heat form the indoor to the space outside the

building.

d) Condenser Motor is located here. The motor usually has two to three speeds. Smaller unit may have only one speed of control and turns on/off simultaneously with the compressor.

INDOOR UNIT :

The indoor unit houses the evaporator coil or the cooling coil, a long blower and the filer. After

passing from the expansion coil, the chilled Freon fluid enters the cooling coil. The blower sucks the

hot, humid and filtered air from the room and it blows over the cooling coil. As the air passes over

cooling coiling its temperature reduces drastically and also loses the excess moisture comfortable

conditions of around 25 to 27 C as per the standard requirements. It can be mounted on the ceiling,

wall or simply as a console unit on the floor.


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It consists of the following parts :

a) Evaporator coil is where the heat exchange is done with the room. It consists of fins and tubes.b) Control Panel is where user control the

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