workshop practice manual 2016

LABORATORY MANUAL

OF

WORKSHOP PRACTISE

Department of Mechanical Engineering

Muffakham Jah College of Engineering and Technology

(THE SULTAN UL ULOOM EDUCATION SOCIETY)

Affiliated to Osmania University & Recognized by AICTE

Banjara Hills, Hyderabad 5000 34

The following faculty members has contributed for preparing the Workshop Practice manual.

CARPENTRY O.Hemalatha & Hasham Ali

FITTING Syed Khader Basha & G Bhasker

HOUSE WIRING Afroz Mehar & G Sailaja

PLUMBING G Prasanna Kumar & H K Dora

SHEET METAL V Dharam Singh & S Irfan Sadak

WELDING Abdul Rahim Junaidi & Md Yahiya

Work shop Incharge Module Co ordinator Program Co ordinator HOD

Joseph George Konnuly J. Dhanraj Pamar AS Reddy/SE Khainy Dr.Shaik Khader Vali

CARPENTRY

INSTRUCTIONS TO THE STUDENTS

1. Enter the lab with proper dress- code (blue apron and shoes)

2. Maintain a 200 pages white long note book and divide it into four parts with the Titles of the

trades namely foundry, plumbing, black smithy and Welding.

3. Draw the figures of tools and equipment‟s proportionately using pencil only on the left side of

the page.

4. Write the related theory part only on the right side of the page.

5. For every experiment, draw the related figure and write the individual procedure in the

observation book and take signature by the concerned technician. Write the date and Experiment

number in the observation book. And take signature of staff member on index page of lab manual.

6. Only after taking signature in the observation book, write the record. Both will be checked.

Marks are allotted for your regularity. Performance of the students will be assessed for every

session of workshop being conducted.

7. The records should be written up to date without delay. They should be signed by the

concerned faculty.

8. Medical kits provided in the First – Aid Box. The students can utilize the available Medicines

if at all there is any necessity.

INDEX

1. CARPENTRY

Introduction

Tools

Safety precautions

Exercises

1. Practice in Planning, sawing and chiseling

2. Preparing cross Half Lap Joint

3. Preparing Dove Tail Joint.

BEYOUND THE SYLLABUS:

1. Preparing the Mortise and Tenon joint

CHAPTER-1

CARPENTRY

INTRODUCTION:

Carpentry may be defined as the process of making wooden articles and components such as

roots, floors, partitions, doors and windows. Carpentry involves cutting, shaping and fastening

wood and other materials together to produce a finished product. It deals with the building work,

furniture, either, cabinet, making , etc, Joinery. Preparation of joints is one of the important

operations in wood work. Joinery denotes connecting the wooden parts using different points such

as lap joints, mortise and T- joints, bridle joints, etc.

In carpentry workshop, wooden pieces of commercial sizes are given specific shape and size, as

per the requirements. The processes involved in carpentry shop are making layout, marking,

sowing, planning, chiseling joint making etc.

The raw material and tools used in carpentry shop are various are wood, nut, screw, nut and bolt

and glue etc. The tools are classified as marking, cutting, planning, chiseling, striking etc.

VARIOUS TYPES OF TIMBER AND PRACTICE BOARDS

Types of Wood – Common wood are generally classified according to their degree of hardness of

softness.

1. Hardwood- Hard wood has closed structure, heavy in weight, dark in color and is difficult

to work on it, annual rings are not distinct and good tensile strength.

2. Soft Wood- Hard wood has less weight, less durable and is easy to work out. Soft wood

catches fire soon as compared to hardwood, annual rings are quite distinct.

3. Plywood: It consists of more than three layers. Middle layer is called care which is thick and

not of good quality. The top and bottom are called as face ply‟s which is glued on the care at

top and bottom. The grains of adjacent layers are kept perpendicular to each other which prevents

plywood form war page.

Types of Ply – Ply Board, Commercial Board, Chip Board, Soft Board.

Advantage of Ply wood

1. Lighter in weight and easy to work.

2. Can be used for decorating the furniture as well as houses.

3. It is also available in bigger sizes.

4. Possesses bottom strength then solid wood of same thickness.

CHARACTERISTICS OF GOOD TIMBER

Timber is the name given to the wood obtained from well grown trees. The trees are cut, sawn

into various sizes to suit building purposes.

The word, „grain „, as applied to wood, refers to the appearance or pattern of the wood on the cut

surfaces. The grain of the wood is a fibrous structure and to make it string, the timber must be so

cut, that the grains run parallel to the length.

The good timber must possess the following characteristics

a. It should have minimum moisture content, i.e., the timber should be well seasoned.

b. The grains of wood should be straight and long.

c. It must retain its straightness after seasoning.

d. It should produce near metallic sound on hammering.

e. It should be free from knots or cracks.

f. It should be of uniform color, throughout the part of the wood.

g. It should respond well to the finishing and polishing operations.

h. During driving the nails and screw, it should not split easily.

MARKET SIZES OF TIMBER:

Timber is sold in the market in various standard shapes and sizes. The following are the common

shapes and sizes:

1. Log – The trunk of the tree, which is free from branches.

2. Balk – The log, sawn to have roughly square cross-section.

3. Post – A timber piece, round or square(sawn) in cross section , having its diameter or side,

varying from 175 to 300 mm.

4. Plank – A sawn timber piece, with more than 275 mm in width, 50 to 150 mm in thickness

and 2.5 to 6.5 meters in length.

5. Board – A sawn timber piece, below 50 mm thickness and more than 125 mm in width.

6. Batten – A sawn timber piece, below 175 mm in width and 30 to 50 mm in thickness.

7. Scantlings or reapers – sawn timber pieces of assorted and non- standard sizes, which do

not confirm to the above shapes and sizes.

DEFECTS IN TIMBER

Following are the common defects occurring in the wood and it can be divided into following

three categories.

1. Natural Defects are the defects which are caused in the tree due to abnormality in the grouts.

2. Defects are also caused during seasoning operation.

3. Some defects are also there due to termites or insects.

Natural defects – Wood being a product of nature is subjected of natural defects, some of them

are explained below:

1. Shakes: Shakes are caused due to the separation of wood grains, some times, burning of

tissues and shrinkage of interior parts takes place which causes radial or circular rupture in

tissues and creates cavities, which are called shakes are of three types

(i) Heart and star shakes: These defects in the heart wood in other older tree, especially.

Hemlock heart shakes can be evidenced by a small point cavity at the center of the wood as

shown in fig.

(ii) Wind shakes or Cup shaker: The separation of annual rings is called wind shake or cup

shake. These defects are common in lines.

(iii) Radial Shakes: Radial shakes are the radial splits extending from bark towards the center.

These cracks over the cross section of the log are winder at the bark and narrow down near the

center as shown in fig.

2. Knots: Knot represent irregular in the body of a tree which interrupt the smooth course of the

grand. The fibers of the tree are turned from their normal shaped and grow around the knot at

that point of a tree where a link is being formed. Knots are two types:

(i) Dead knots: When the separation of benches or hurbs takes place before the tree is cut,

the knot thus formed called leaf knot. This knot is not held firmly and wood having leaf knot

is not recommended for engineering purposes.

(ii) Live knots: If the separation occurs after falling of a tree the knot thus formed is called

live knot. A wood having live knot can be used for engineering purposes.

SEASONING OF WOOD

The process of removing moisture from freshly cut down trees is known as seasoning. In these

trees the percentage of moisture is very high. The wood uses of engineering purposes containing

high percentage of moisture may cause many types of problems, such as shrinkage, warpage

distortion etc. To a point this, seasoning is done. After seasoning the percentage of moisture is

reduced to 10- 20%.

Types of Seasoning

(i) Air Seasoning: In this method, the timber balks are stacked in a sheet such that they are not

directly exposed to sun and rain but a free circulation of air takes place through them. The timber

balks are allowed to remain in that condition for a long times. The balks be periodically turned

upside which accelerates the rate of drying. Due to the circulation of free air through the stack,

the excess moisture evaporates and the wood gets seasoned. This is the commonly used method

which takes much time but proper seasoning can be easily done with a little care.

(ii) Water Seasoning: In this method, timber balks are immersed in flowing water for a fortnight.

The flowing stream of water removes the sap. The timber is then taken out and air seasoning is

done as usual. This method takes less time but the strength of wood reduced.

(iii) Artificial or Kiln Seasoning: This is a quick process of seasoning of this method,

the timber balks are stacked and over large trollies which are then driven into hot chambers or

kilus. Hot air or dry stem is pushed into the chamber under controlled temperature conditions.

The moisture content is reduced because the evaporation takes place and ultimately the timber

gets seasoned.

TOOLS

MARKING AND MEASURING TOOLS

Accurate marking and measurement is very essential in carpentry work, to produce parts to

exact size. To transfer dimensions onto the work; the following are the marking and measuring

tools that are required in a carpentry shop.

1. Steel rule and Steel tape

Steel rule shown in Figure 1.1a is a simple measuring instrument consisting of a long, thin metal

strip with a marked scale of unit divisions. It is an important tool for linear measurement.

Steel tape shown in figure 1.1b is used for large measurements, such as marking on boards and

checking the overall dimensions of the work.

Figure 1.1a: Steel rule

Figure 1.1b: Steel tape

2. Marking gauge

Marking gauge shown in figure1.2.a is a tool used to mark lines parallel to the edge of a wooden

piece. It consists of a square wooden stem with a sliding wooden stock (head) on it. On the stem

is fitted a marking pin, made of steel. The stock is set at any desired distance from the marking

point and fixed in position by a screw. It must be ensured that the marking pin projects through

the stem, about 3 mm and the end are sharp enough to make a very fine line.

A mortise gauge shown in Figure 1.2.b consists of two pins. In this, it is possible to adjust the

distance between the pins, to draw two parallel lines on the stock.

a. Marking gauge b. Mortise gauge

Figure 1.2: Marking gauges

3 Try‐square

Try square shown in figure 1.3 is used for marking and testing the squareness and straightness of

planed surfaces. It consists of a steel blade, fitted in a cast iron stock. It is also used for checking

the planed surfaces for flatness. Its size varies from 150 to 300 mm, according to the length of the

blade. It is less accurate when compared to the try‐square used in the fitting shop.

Figure 1.3: Try square

4. Compass and divider

Compass and divider shown in figure 1.4, are used for marking arcs and circles on the planed

surfaces of the wood.

5. Scriber or marking knife

Scriber as shown in figure1.5a is used for marking on timber. It is made of steel having one end

pointed and the other end formed into a sharp cutting edge.

6. Bevel

Bevel as shown in figure 1.5b is used for laying‐out and checking angles. The blade of the bevel

is adjustable and may be held in place by a thumb screw. After it is set to the desired angle, it can

be used in much the same way as a try‐square. A good way to set it to the required angle is to

mark the angle on a surface and then adjust the blade to fit the angle.

Figure 1.4: Compass and Divider

Figure 1.5a.Scriber or marking Knife

Figure 1.5b: Bevel

HOLDING TOOLS

1 Carpenter's vice

Figure1.6 shows the carpenter's bench vice, used as a work holding device in a carpenter shop.

Its one jaw is fixed to the side of the table while the other is movable by means of a screw and a

handle.

The Carpenter's vice jaws are lined with hard wooden' faces.

Figure 1.6: Carpenters vice

Figure 1.7: C‐clamp

2. C‐clamp

Figure 1.7 shows a C‐clamp, which is used for holding small works.

3. Bar cramp

Figure 1.8 shows a bar cramp. It is made of steel bar of T‐section, with malleable iron fittings

and a steel screw. It is used for holding wide works such as frames or tops.

Figure 1.8: bar cramp

PLANING TOOLS

Planing is the operation used to produce flat surfaces on wood. A plane is a hand tool used for

this purpose. The cutting blade used in a plane is very similar to a chisel. The blade of a plane is

fitted in a wooden or metallic block, at an angle.

1. Jack plane

Jack Plane as shown in figure 1.9 a & b is the most commonly used general purpose plane. It is

about 35 cm long. The cutting iron (blade) should have a cutting edge of slight curvature. It is

used for quick removal of material on rough work and is also used in oblique planning.

2. Smoothing plane

Smoothing Plane as shown in figure 1.9c is used for finishing work and hence, the blade should

have a straight cutting edge. It is about 20 to 25 cm long. Being short, it can follow even the slight

depressions in the stock, better than the jack plane. It is used after using the jack plane.

3. Rebate plane

Rebate Plane as shown in figure 1.9d is used for making a rebate. A rebate is a recess along the

edge of a piece of wood, which is generally used for positioning glass in frames and doors.

4. Plough plane

Plough Plane as shown in figure 1.9e is used to cut grooves, which are used to fix panels in a

door. Figure .9 shows the various types of planes mentioned above.

a)Wood jack plane ` b)Metal jack plane

c)smoothing Plane d) Rebate plane

e) Plough Plane

Figure 1.9: Types of planes

CUTTING TOOLS

1. Saws

A saw is used to cut wood into pieces. There are different types of saws, designed to suit

different purposes. A saw is specified by the length of its toothed edge.

i) Cross‐cut or hand saw

Cross cut saw as shown in figure1.10 is used to cut across the grains of the stock. The teeth are so

set that the saw kerf will be wider than the blade thickness. This allows the blade to move freely

in the cut, without sticking.

ii) Rip saw

Rip saw as shown in figure 1.10 is used for cutting the stock along the grains. The cutting edge of

this saw makes a steeper angle, i.e., about 60° whereas that of crosscut saw makes an angle of 45°

with the surface of the stock.

iii) Tenon saw

Tenon saw as shown in figure 1.11 is used for cutting the stock either along or across the grains.

It is used for cutting tenons and in fine cabinet work. However, it is used for small and thin cuts.

The blade of this saw is very thin and so it is stiffened with a thick back steel strip. Hence, this is

sometimes called as back‐saw. In this, the teeth are shaped like those of cross‐cut saw.

iv) Compass saw

Compass saw as shown in figure 1.12 has a narrow, longer and stronger tapering blade, which is

used for heavy works . It is mostly used in radius cutting. The blade of this saw is fitted with an

open type wooden handle.

Figure 1.10: Cross cut and rip saw

Figure 1.11: Tenon Saw

Figure 1.12: Compasss Saw

2. Chisels

Chisels are used for cutting and shaping wood accurately. Wood chisels are made in various

blade widths, ranging from 3 to 50 mm. They are also made in different blade lengths. Most of

the wood chisels are made into tang type, having a steel shank which fits inside the handle (Figure

1.13). These are made of forged steel or tool steel blades.

Figure 1.13: Parts of chisel

i) Firmer chisel

The word 'firmer' means 'stronger' and hence firmer chisel is stronger than other chisels. It is a

general purpose chisel and is used either by hand pressure or by a mallet. The blade of a firmer

chisel is flat, as shown in Figure 1.14 a.

ii) Dovetail chisel

It has a blade with a beveled back, as shown in Figure, due to which it can enter sharp comers

for finishing, as in dovetail joints, as shown in figure 1.14b

iii) Mortise chisel

Mortise chisel as shown in figure 1.14c is used for cutting mortises and chipping inside holes, etc.

The cross‐section of the mortise chisel is proportioned to withstand heavy blows during

mortising. Further, the cross‐section is made stronger near the shank.

a. Firmer b. Dovetail c. Mortise

Figure 1.14: Types of chisels

DRILLING AND BORING TOOLS

1. Carpenter’s brace

Carpenters brace as shown in figure 1.15a is used for rotating auger bits, twist drills, etc., to

produce holes in wood. In some designs, braces are made with ratchet device. With this, holes

may be made in a corner where complete revolution of the handle cannot be made. The size of a

brace is determined by its sweep.

2. Auger bit

Auger bit as shown in figure 1.15b is the most common tool used for making holes in wood.

During drilling, the lead screw of the bit guides into the wood, necessitating only moderate

pressure on the brace. The helical flutes on the surface carry the chips to the outer surface.

3. Hand drill

Carpenter's brace is used to make relatively large size holes; whereas hand drill as shown in

figure 1.15c is used for drilling small holes. A straight shank drill is used with this tool. It is

small, light in weight and may be conveniently used than the brace. The drill bit is clamped in the

chuck at its end and is rotated by a handle attached to gear and pinion arrangement.

4. Gimlet

Gimlet as shown in figure 1.15d has cutting edges like a twist drill. It is used for drilling large

diameter holes with the hand pressure.

a) Carpenters brace b) Auger Bit c) Hand Drill d) gimlet

Figure 1.15: Drilling tools

MISCELLANEOUS TOOLS

1. Mallet

Mallet as shown in figure 1.16a is used to drive the chisel, when considerable force is to be

applied, which may be the case in making deep rough cuts. Steel hammer should not be used for

the purpose, as it may damage the chisel handle. Further, for better control, it is better to apply a

series of light taps with the mallet rather than a heavy single blow.

2. Pincer

It is made of two forged steel arms with a hinged joint and is used for pulling‐out small nails

from wood. The inner faces of the pincer (figure 1.16b) jaws are beveled and the outer faces are

plain. The end of one arm has a ball and the other has a claw. The beveled jaws and the claw are

used for pulling out small nails, pins and screws from the wood.

3. Claw hammer

It has a striking flat face at one end and the claw at the other, as shown in figure1.16c. The face is

used to drive nails into wood and for other striking purposes and the claw for extracting relatively

large nails out of wood. It is made of cast steel and weighs from 0.25 kg to 0.75 kg.

4. Screw driver

It is used for driving screws into wood or unscrewing them. The screw driver of a carpenter is

different from the other common types, as shown in figure1.16f The length of a screw driver is

determined by the length of the blade. As the length of the bladeincreases, the width and thickness

of the tip also increase.

5. Wood rasp file

It is a finishing tool used to make the wood surface smooth, remove sharp edges, finish fillets

and other interior surfaces as shown in figure1.16d. Sharp cutting teeth are provided on its surface

for the purpose. This file is exclusively used in wood work.

6. Bradawl

It is a hand operated tool, used to bore small holes for starting a screw or large nail.as shown in

figure 1.16e

a.Mallet

b. Pincer c. Claw hammer

d. Wood rasp file e. Bradawl

f. Screw driver

Figure 1.16: Miscellaneous tools

WOOD WORKING TECHNIQUES

Selection and Laying –out

While selecting the stock, the ends must be observed and if it contains small splits or defects, they

must be trimmed, and while laying-out, 1to 2 mm must be allowed in thickness, about 5mm for

each width and about 20mm on length for planning and /or cutting. It must also be ensures that

the grains are in the right direction.

Marking

Accurate measuring and marking are the first requirement for success in wood work. Marking to

the desired dimension is done by placing a square or rule and then making a fine narrow line,

close to the edge of the square or rule. In most of the cases, a pencil serves the purpose for

marking. A soft pencil makes a line that is easily seen and hence preferred. For accurate work,

however, it is advisable to use a blade for making.

For marking with the help of a marking gauge, it must be held firmly with fingers around the head

and with the thumb behind the marking point and the gauge must be pushed forward against the

surface. While pushing, the gauge must be kept slightly forward so that , the point gets dragged at

a slight angle.

If the work is to be finished with a plane, an allowance must be provided for this, while marking

However, it must be borne in mind that removing excess material with a plane is a tedious job and

hence should be kept to a minimum.

Laying-out an Angle

The following are the steps involved in laying-out an angle on a wooden surface.

1. Set the bevel to the required angle.

2. Hold the handle firmly against the face or edge of the board.

3. Mark along the edge of the blade with a pencil or knife.

Plane Adjustment

A plane will not produce proper work surface unless the blade is sharp and properly adjusted.

Out of the two adjustments that are in built in the design of the plane, one is to regulate the depth

of cut and the other is to straighten the blade so that , it produces a flat surface.

The plane adjustment may be checked by feeling the corners of the blade with the first two

fingers. By this, it may be easily detected and adjusted if one corner projects through the throat

farther than the other. For proper work, turn the adjustment nut until a fine shaving is cut when

the plane is moved over the surface.

Method of using the plane.

The following may be noted while using the plane:

1. Hold the handle of the plane with the right hand and the knob with the left band.

2. Stand to the left side of the job, feet apart and with the left foot slightly ahead.

3. While pushing the plane, gradually shift weight to the left foot.

4. While planning , keep the fore arm straight in-line behind the plane

NOTE: i) Always plane along the grains. Planning against the grains will result in rough work.

ii) When not in use, lay the plane on its side. This prevents the cutting edge becoming dull

by contact with the bench top.

Planing a Surface

Planing is the first thing to be done to build any project in carpentry. The following are the steps

involved in planning a surface:

1. Beginning at one edge of the stock, plane with full length strokes to the other edge.

2. Use the edge of a steel rule to test the surface , by placing the edge in various positions on

the surface and see the underneath to locate high and low places. For this , the order of

checking is as follows:

i) First place the straight edge cross-wise on the stock and move it slowly from one

end to the other.

a. Butt b. Dowell c. Dado d. Rabbet

e. Lap f. Mortise and tenon g. Miter

Figure 1.17: Common wood joints

Lap joints

In lap joints, an equal amount of wood is removed from each piece, as shown in figure 1.17. Lap

joints are easy to layout, using a try‐square and a marking gauge. The layout may also be made by

lapping the pieces to be joined and along the edge of one piece, marking lines on the other.

Here too, while laying-out the joint, Follow the procedure suggested for sawing and removing the

waste stock. If the joint is found to be too tight, it is better to reduce the width of the mating piece,

instead of trimming the shoulder of the joint. This type of joint is used for small boxes to large

pieces of furniture.

SAFE PRACTICE

General

1. Tools that are not being used should always be kept at their proper places.

2. Make sure that your hands are not in front of sharp edged tools while you are using them.

3. Use only sharp tools. A dull tool requires excessive pressure, causing the tool to slip.

4. Wooden pieces with nails, should never be allowed to remain on the floor.

Saws

Be careful when you are using your thumb as a guide in cross‐cutting and ripping.

Chisels

1. Test the sharpness of the cutting edge of chisel on wood or paper, but not on your hand.

2. Never chisel towards any part of the body.

Screw driver.

1. Select the longest screw driver that is appropriate for the job intended. The longer the tool

, the greater the effort applied.

2. The tip of the screw driver must fit the slot without wobbling. The width of the tip should

be equal to the length of the screw slot.

3. Keep the screw driver properly pointed to prevent injury to hands.

CARE AND MAINTENANCE OF TOOLS

Chisels

1. Do not use chisels where nails are present.

2. Do not use chisel as a screw driver.

Saws

1. Do not use a saw with a loose handle.

2. Always use triangular file for sharpening the teeth.

3. Apply grease when not in use

EXERCISE-1

AIM: To make the wooden piece according to dimensions given , it is the exercise for practice in

planning , sawing and chiseling.

ALL DIMENSIONS ARE IN MM

Material Required: Teak Wood dimensions : 300 mm x 50 mm. x 25 mm.

Tools required : Jack Plane, tenon saw, chisel, mallet.

Measuring and marking tools: Marking gauge, steel scale , try square.

Procedure:

Order of operation:

1. Choose the better one the top and bottom surface of the piece and plane it smooth. Test the

two sides with steel scale length wise, cross wise and diagonally for flatness. This will be

„FACE SIDE‟ and is marked thus‟&‟ with the tail towards the better edge.

2. Place the work piece in the vice and plane this edge. This will be „FACE EDGE‟. Test it

with steel scale as before and check squareness with the face side by a try square. Mark it

thus „Λ‟ with the apex towards the face side.

3. Mark a line with marking gauge 45 mm away from the „FACE EDGE‟.

4. Place the work piece in the vice and plane this edge down to the marked gauge line. Test

with steel scale and try square.

5. Mark a line with marking gauge 20 mm. away from the face edge. Make correspondingly

on the opposite edge.

6. Place the work piece with face down and plane the bottom side upto the gauge line on

both the edges. Test its squareness and trueness as before.

THE WORK PIECE HAS NOW BEEN PLANES TRUE AND SQUARE

7. Draw a line 10mm. away from the face side on the face edge.

8. With the pencil point locate the positions of the slots according to given sketch . before

this operation remove about 10 mm, from either side as waste wood and start marking

from this line.

9. Using the try square mark slots with pencil on the face side.

10. Square down these lines upto gauge lines on the two face edges.

11. Mark „ X‟ over the work piece an portions to be removed.

12. Make saw cuts close up against the lines on the face side and upto gauge lines on the

edges. The cuts should be towards the portion to be removed.

13. Fix the work piece again and chisel out the slots, starting from top to bottom at an angle

and gradually reaching the gauge line. reverse the work piece and repeat the same

operation. Finally, clear the bottom portion of each slot smooth and flat.

14. Saw out the waste wood from both the ends.

NOTE:

1. Use a chisel of smaller size than the slot to be cut.

2. Be careful to see the saw does not run out of the marked lines.

EXERCISE-2

AIM: To make the Cross Half Lap Joint according to the given dimensions, from the given

wooden

piece .





Procedure:

Order of operation:

1. The given Wooden piece is checked to ensure its correct size.

2. The Wooden piece is firmly clamped in the carpenter's vice and any two adjacent faces

are planed by the jack plane and the two faces are checked for squareness with the try

square.

3. Marking gauge is set and lines are drawn at 44 and 88 mm, to mark the thickness and

width of the model respectively.

4. The excess material is first chiseled out with firmer chisel and then planed to correct size.

5. The mating dimensions of the parts X and Yare then marked using scale and marking

gauge.

6. Using the cross‐ cut saw, the portions to be removed are cut in both the pieces, followed

by chiseling and also the parts X and Yare separated by cross cutting, using the tenon saw.

7. The ends of both the parts are chiseled to exact lengths.

8. A fine finishing is given to the parts, if required so that, proper fitting is obtained.

9. The parts are fitted to obtain a slightly tight joint.

NOTE:



RESULT: The cross half lap joint is thus made by following the above sequence of

operations.

EXERCISE-3

AIM: To make the Dove Tail Joint according to the given dimensions, from the given wooden

piece ..

ALL DIMENSION ARE IN MM




Procedure:

Order of operation:


11. The Wooden piece is firmly clamped in the carpenter's vice and any two adjacent faces

are planed by the jack plane and the two faces are checked for squareness with the try

square.



13. The excess material is first chiseled out with firmer chisel and then planed to correct size.

14. The mating dimensions of the parts X and Yare then marked using scale and marking

gauge.

15. Using the cross‐ cut saw, the portions to be removed are cut in both the pieces, followed

by chiseling and also the parts X and Yare separated by cross cutting, using the tenon saw.


17. A fine finishing is given to the parts, if required so that, proper fitting is obtained.

18. The parts are fitted to obtain a slightly tight joint.

NOTE:



RESULT: The Dove tail Lap joint is thus made by following the above sequence of

operations.

EXERCISE-4

AIM: To make the Mortise and Tenon Joint according to the given dimensions, from the given

wooden piece .

X Y





Procedure:

Order of operation:


2. The Wooden piece is firmly clamped in the carpenter's vice and one of its faces are planed

by the jack plane and checked for straightness.

3. The adjacent face is then planed and the faces are checked for squareness with the

try‐ square.



5. The excess material is first chiseled out with the firmer chisel and then planed to correct

size.

6. The mating dimensions of the parts X and Yare then marked using the scale and marking

gauge.

7. Using the cross‐ cut saw, the portions to be removed in part Y (tenon) is cut, followed by

chiseling.

8. The material to be removed in part X (mortise) is carried out by using the mortise and

firmer chisels.

9. The parts X and Yare separated by cross‐ cutting with the tenon saw.


11. Finish chiseling is done wherever needed so that, the parts can be fitted to obtain a near

tight joint.

NOTE:



RESULT: The mortise and tenon joint is thus made by following the above sequence of

operations.

FITTING SHOP

CONTENTS

Preface

Table of Contents page

1. Fitting Shop

1.1 Introduction

1.2 Holding tools

1.3 Marking and measuring tools

1.4 Cutting tools

1.5 Finishing tools

1.6 Miscellaneous tools

1.7 Safe practice

1.8 Models for preparation

Exercises

FITTING SHOP

1.1 INTRODUCTION

Machine tools are capable of producing work at a faster rate, but, there are occasions when components are processed at the bench. Sometimes, it becomes

necessary to replace or repair component which must be fit accurately with another

component on reassembly. This involves a certain amount of hand fitting. The assembly of machine tools, jigs, gauges, etc, involves certain amount of bench work. The accuracy of

work done depends upon the experience and skill of the fitter.fitting deals which the assembly

of mating parts, through removal of metal, to obtain the required fit.

Both the bench work and fitting requires the use of number of simple hand tools

and considerable manual efforts. The operations in the above works consist of filing,

chipping, scraping, sawing drilling, and tapping.

1.2 HOLDING TOOLS

1.2.1 Bench vice

The bench vice is a work holding device. It is the most commonly used vice in a fitting

shop. The bench vice is shown in Figure 1.1.

Figure 1.1: Bench

Vice

It is fixed to the bench with bolts and nuts. The vice body consists of two main parts, fixed jaw and movable jaw. When the vice handle is turned in a clockwise direction, the

sliding jaw forces the work against the fixed jaw. Jaw plates are made of hardened steel.

Serrations on the jaws ensure a good grip. Jaw caps made of soft material are used to protect

finished surfaces, gripped in the vice. The size of the vice is specified by the length of the jaws.

The vice body is made of cast Iron which is strong in compression, weak in tension and so fractures under shocks and therefore should never be hammered.

1.2.2 V‐block

V‐block is rectangular or square block with a V‐groove on one or both sides opposite

to each other. The angle of the ‘V’ is usually 900. V‐block with a clamp is used to hold cylindrical work securely, during layout of measurement, for measuring operations or for drilling for this the bar is faced longitudinally in the V‐Groove and the screw of V‐clamp is tightened. This grip the rod is firm with its axis parallel to the axis of the v‐groove.

1.2.3 C‐Clamp

This is used to hold work against an angle plate or v‐block or any other surface, when

gripping is required. ts fixed jaw is shaped like English alphabet ‘C’ and the movable jaw is round

in shape and directly fitted to the threaded screw at the end .The working principle of this clamp is the same as that of the bench vice.

F

Figure 1.2:V-block Figure 1.3:C-clamp

1.3MARKING&MEASURINGTOOlS

1.3.1 Surface Plate

The surface plate is machined to fine limits and is used for testing the flatness of the work piece. It is also used for marking out small box and is more precious than the marking

table. The degree of the finished depends upon whether it is designed for bench work in a fitting

shop or for using in an inspection room; the surface plate is made of Cast Iron, hardened Steel or Granite stone. It is specified by length, width, height and grade. Handles are provided on two

opposite sides, to carry it while shifting from one place to another.

Figure 1.5: Angle plate Figure 1.4: Surface plate

1.3.2

Trysquare

It is measuring and marking tool for 90oangle .In practice, it is used for checking the squareness of many types of small works when extreme accuracy is not required .The blade of the Try square is made of hardened steel and the stock of cast Iron or steel. The size of the Try square is specified by the length of the blade.

Figure 1.6: Try square

1.3.3

Scriber

A Scriber is a slender steel tool, used to scribe or mark lines on metal work pieces. It is made of hardened and tempered High Carbon Steel. The Tip of the scriber is generally ground at

12oto 15o. It is generally available in lengths, ranging from 125mm to 250mm .It has two pointed ends the bent end is used for marking lines where the straight end cannot reach.

Figure 1.7: Scriber

1.3.4 Odd leg Caliper

This is also called ‘Jenny Caliper’ or Hermaphrodite. This is used for marking parallel liners from a finished edge and also for locating the center of round bars; it has one leg

pointed like a divider and the other leg bent like a caliper. It is specified by the length of the leg up to the hinge point.

1.3.5 Divider

It is basically similar to the calipers except that its legs are kept straight and pointed at the measuring edge. This is used for marking circles, arcs laying out perpendicular

lines, by setting lines. It is made of case hardened mild steel or hardened and tempered low

carbon steel. Its size is specified by the length of the leg.

1.3.6 Trammel

Figure 1.8: Odd leg caliper and spring divider

Trammel is used for drawing large circles or arcs.

1.3.7 Punches

These are used for making indentations on the scribed lines, to make them visible

clearly. These are made of high carbon steel. A punch is specified by its length and diameter (say

as 150’ 12.5mm). It consists of a cylindrical knurled body, which is plain for some length at the

top of it. At the other end, it is ground to a point. The tapered point of the punch is hardened

over a length of 20 to 30mm.

Dot punch is used to lightly indent along the layout lines, to locate center of holes and to provide a small center mark for divider point, etc. for this purpose, the punch is ground to a conical point having 60° included angle.

Center punch is similar to the dot punch, except that it is ground to a conical point having 90°

included angle. It is used to mark the location of the holes to be drilled.

Figure 1.9:

Punches

1.3.8 Calipers

They are indirect measuring tools used to measure or transfer linear dimensions. These

are used with the help of a steel Rule to check inside and outside measurements. These

are made of Case hardened mild steel or hardened and tempered low carbon steel. While

using, but the legs of the caliper are set against the surface of the work, whether inside or outside and the distance between the legs is measured with the help of a scale and the same can

be transferred to another desired place. These are specified by the length of the leg. In the case

of outside caliper, the legs are bent inwards and in the case of inside caliper, the legs bent

outwards.

Figure

1.10:Calipers

1.3.9 Vernier Calipers

These are used for measuring outside as well as inside dimensions accurately. It may also be used as a depth gauge. It has two jaws. One jaw is formed at one end of its main scale

and the other jaw is made part of a vernier scale.

Figure 1.11: Vernier caliper

1.3.10 Vernier Height Gauge

The Vernier Height gauge clamped with a scriber. It is used for Lay out work and offset

scriber is used when it is required to take measurement from the surface, on which the

gauge is standing. The accuracy and working principle of this gauge are the same as those of the vernier calipers. Its size is specified by the maximum height that can be measured by it. It

is made of Nickel‐Chromium Steel.

Figure 1.12: Vernier Height gauge

1.4 CUTTING TOOLS

1.4.1 Hack Saw

The Hack Saw is used for cutting metal by hand. It consists of a frame, which holds a thin blade, firmly in position. Hacksaw blade is specified by the number of teeth for centimeter.

Hacksaw blades have a number of teeth ranging from 5 to 15 per centimeter (cm). Blades

having lesser number of teeth per cm are used for cutting soft materials like aluminum, brass and bronze. Blades having larger number of teeth per centimeter are used for cutting hard

materials like steel and cast Iron.

Hacksaw blades are classified as (i) All hard and (ii) flexible type. The all hard blades are

made of H.S.S, hardened and tempered throughout to retain their cutting edges longer. These are used to cut hard metals. These blades are hard and brittle and can break easily by

twisting and forcing them into the work while sawing. Flexible blades are made of H.S.S or low alloy steel but only the teeth are hardened and the rest of the blade is soft and flexible.

These are suitable for use by un‐skilled or semi‐skilled persons.

Figure 1.13: Hacksaw frame with

blade

The teeth of the hacksaw blade are staggered, as shown in figure and known as a ‘set of

teeth’. These make slots wider than the blade thickness, preventing the blade from jamming.

Figure 1.14: Set of

teeth

1.4.2 Chisels

Chisels are used for removing surplus metal or for cutting thin sheets. These tools

are made from 0.9% to 1.0% carbon steel of octagonal or hexagonal section. Chisels are

annealed, hardened and tempered to produce a tough shank and hard cutting edge. Annealing relieves the internal stresses in a metal. The cutting angle of the chisel for general purpose is

about 60°.

Figure 1.15:

Flatchisel

1.4.3 Twist Drill

Twist drills are used for making holes. These are made of High speed steel. Both

straight and taper shank twist drills are used. The parallel shank twist drill can be held in an

ordinary self – centering drill check. The tapper shank twist drill fits into a corresponding tapered bore provided in the drilling machine spindle.

Figure 1.16: Twistdrills

1.4.4 Taps and Tap wrenches

A tap is a hardened and steel tool, used for cutting internal thread in a drill hole. Hand Taps are

usually supplied in sets of three in each diameter and thread size. Each set consists of a

tapper tap, intermediate tap and plug or bottoming tap. Taps are made of high carbon steel or

highspeedsteel.

Figure 1.17: Taps and tap

wrench

1.4.5 Dies and die‐holders

Dies are the cutting tools used for making external thread. Dies are made either solid

or split type. They are fixed in a die stock for holding and adjusting the die gap. They are made of Steel or High Carbon Steel.

Figure 1.18: Dies and die

holder

1.4.6 Bench Drilling Machine

Holes are drilled for fastening parts with rivets, bolts or for producing internal

thread. Bench drilling machine is the most versatile machine used in a fitting shop for the

purpose. Twist drills, made of tool steel or high speed steel are used with the drilling machine

for drilling holes.

Following are the stages in drilling work

1. Select the correct size drills, put it into the check and lock it firmly

2. Adjust the speed of the machine to suit the work by changing the belt on the pulleys. Use

high speed for small drills and soft materials and low speed for large diameter drills and hard materials.

3. Layout of the location of the pole and mark it with a center punch.

4. Hold the work firmly in the vice on the machine table and clamp it directly on to the machine

table.

5. Put on the power, locate the punch mark and apply slight pressure with the Feed Hand.

6. Once Drilling is commenced at the correct location, apply enough pressure and continue

drilling.When drilling steel apply cutting oil at the drilling point.

7. Release the pressure slightly, when the drill point pierces the lower surface of the

metal. This prevents the drill catching and damaging the work or drill.

8. On completion of drilling retrace the drill out of the work and put‐off the power supply.

Figure 1.19: Bench

drill

1.5 FINISHING TOOLS

1.5.1 Reamers

Reaming is an operation of sizing and finishing a drilled hole, with the help of a cutting tool called reamer having a number of cutting edges. For this, a hole is first drilled,

the size of which is slightly smaller than the finished size and then a hand reamer or machine reamer is used for finishing the hole to the correct size.

zHand Reamer is made of High Carbon Steel and has left‐hand spiral flutes so that, it is

prevented from screwing into the whole during operation. The Shank end of the reamer is

made straight so that it can be held in a tap wrench. It is operated by hand, with a tap wrench

fitted on the square end of the reamer and with the work piece held in the vice. The body of

the reamer is given a slight tapper at its working end, for its easy entry into the whole during

operation, it is rotated only in clock wise direction and also while removing it from the whole.

Figure 1.20:

Reamers

1.5.2 Files

Filing is one of the methods of removing small amounts of material from the surface of

a metal part. A file is hardened steel too, having small parallel rows of cutting edges or teeth on its surfaces.

On the faces, the teeth are usually diagonal to the edge. One end of the file is shaped

to fit into a wooden handle. The figure shows various parts of a hand file. The hand file is parallel in width and tapering slightly in thickness, towards the tip. It is provided with double

cut teeth. On the faces, single cut on one edge and no teeth on the other edge, which is known

as a safe edge.

Figure 1.21: Parts of a hand

file

Files are classified according to their shape, cutting teeth and pitch or grade of the

teeth. The figure shows the various types of files based on their shape.

Figure 1.22: Single and double cut files

Figure 1.23: Types of files

1.6 MISCELLANEOUS TOOLS

1.6.1 File card

It is a metal brush, used for cleaning the files, to free them from filings, clogged in‐between the

teeth.

Figure 1.24: File card

1.6.2 Spirit level

It is used to check the leveling of machines.

1.6.3 Ball‐ Peen Hammer

Ball‐ Peen Hammers are named, depending upon their shape and material and specified

by their weight. A ball peen hammer has a flat face which is used for general work and a ball end, particularly used for riveting.

Figure 1.25: Ball peen

hammer

1.6.4 Cross‐Peen Hammer

It is similar to ball peen hammer, except the shape of the peen. This is used for

chipping, riveting, bending and stretching metals and hammering inside the curves and shoulders.

1.6.5 Straight‐Peen Hammer

This is similar to cross peen hammer, but its peen is in‐line with the hammer handle. It

is used for swaging, riveting in restricted places and stretching metals.

Figure 1.26: Cross peen hammer Figure 1.27: Straight peen hammer

1.6.6 Screw driver

A screw driver is designed to turn screws. The blade is made of steel and is available in

different lengths and diameters. The grinding of the tip to the correct shape is very

important.

A star screw driver is specially designed to fit the head of star screws. The end of the blade

is fluted instead of flattened. The screw driver is specified by the length of the metal part from

handle to the tip.

Types of screw driver

1.6.7 Spanners

A spanner or wrench is a tool for turning nuts and bolts. It is usually made of forged

steel. There are many kinds of spanners. They are named according to the application. The size

of the spanner

denotes the size of the bolt on which it can work.

1.7 SAFE PRACTICE

Figure 1.28: Spanners

The following are some of the safe and correct work practices in bench work and fitting

shop, with respect to the tools used

1. Keep hands and tools wiped clean and free of dirt, oil and grease. Dry tools are safer to

use than slippery tools.

2. Do not carry sharp tools on pockets.

3. Wear leather shoes and not sandals.

4. Don’t wear loose clothes.

5. Do no keep working tools at the edge of the table.

6. Position the work piece such that the cut to be made is close to the vice. This practice

prevents springing, saw breakage and personal injury.

7. Apply force only on the forward (cutting) stroke and relieve the force on the return

stroke while sawing and filing.

8. Do not hold the work piece in hand while cutting.

9. Use the file with a properly fitted tight handle.

10. After filing, remove the burrs from the edges of the work, to prevent cuts to the fingers.

11. Do not use vice as an anvil.

12. While sawing, keep the blade straight; otherwise it will break

13. Do not use a file without handle.

14. Clean the vice after use.

1.8 MODELS FOR PRACTICE

Prepare the models, as per the dimensions and fits shown in below.

Figure 1.30: Dovetail Fitting Figure 1.31: V‐fitting

Figure 1.32: Half‐round fitting Figure 1.33: Cross fitting

Figure 1.34: Drilling and Tapping

Exercise

1

SquareFiling

Aim

To file the given two Mild Steel pieces in to a square shape of 48 mm side as shown in Figure

F‐E1

Tools required

Bench vice, set of Files, Steel rule, Try‐square, Vernier caliper, Vernier height gauge, Ball‐peen

hammer, Scriber, Dot punch, Surface plate, Angle plate and Anvil.

Sequence of operations

1. The dimensions of the given piece are checked with the steel rule.

2. The job is fixed rigidly in a bench vice and the two adjacent sides are filed, using the

rough flat file first and then the smooth flat file such that, the two sides are at right angle.

3. The right angle of the two adjacent sides is checked with the try‐square.

4. Chalk is then applied on the surface of the work piece.

5. The given dimensions are marked by scribing two lines, with reference to the above two

datum sides by using Vernier height gauge, Angle plate and Surface plate.

6. Using the dot punch, dots are punched along the above scribed lines.

7. The two sides are then filed, by fitting the job in the bench vice; followed by checking the

flatness of the surfaces.

As the material removal through filing is relatively less, filing is done instead of sawing.

Result

The square pieces of 48 mm side is thus obtained by filing, as discussed above.

a. Raw material b. Finished job

Figure F‐

E1:Squarefiling

Exercise

2

V‐Fitting

AIM:To make V‐ fit from the given two MS plates and drilling and Tapping as shown

in Figure F‐E2

Toolsrequire

d

Bench vice, set of Files, Try‐square, Scriber, Steel rule, Ball‐peen hammer, Dot punch, Hacksaw,

Vernier caliper, Surface plate, Angle plate, Vernier height gauge, 5mm drill bit, 3mm drill bit,

M6 tap set with wrench, Anvil and Drilling machine.

Sequence of

operations

1. The burrs in the pieces are removed and the dimensions are checked with

steel rule.

2. Make both pieces surface levels and right angles by fixing in the Vice, use Files for removing material to get level.

3. With the help of Try square check the right angles and surface

levels.

4. Using Surface plate and Angle plate mark the given two metal pieces as per drawing with Vernier height gauge.

5. Punch the scribed lines with dot punch and hammer keeping on the Anvil. Punch to

punch give 5 mm gap.

6. Cut excess material wherever necessary with Hacksaw frame with blade, Drill bits

and Taps.

7. The corners and flat surfaces are filed by using square/flat and triangular file to get

the sharp corners.

8. Dimensions are checked by vernier caliper and match the two pieces. Any defect noticed, are rectified by filing with a smooth file.

9. Care is taken to see that the punched dots are not crossed, which is indicated by the

half of the punch dots left on the pieces.

Resu

lt

The required V‐ fitting is thus obtained, by following the stages, as described above.

Figure F‐ E2: V‐Fitting

HOUSE WIRING

DIFFERENT SYSTEMS OF WIRING:

The various systems of domestic and industrial wiring are:

(1) Cleat wiring (2) casing capping (3) CTS wiring

(4) Metal sheeted Wiring (5) conduit Wiring

Before deciding the type of wiring to be used at a particular site, the following

points should be considered:

a. Durability: the wire selected should be able the to withstand for a long period against weather changes.

b. Safety: safety is the foremost point to be kept in view while making Decision of the systems of wiring. It may not prove to be risky. At places

which are not free from fire danger conduit wiring is preferred.

c. Cost: the cost of wiring installation is one of the main points to be considered. The system chosen should be economical and within the

means of the individual.

d. Appearance: wiring appearance has its own effect. Architectural Beauty should be kept in view.

1) CLENT WIRING: In this systems V.I.R (Vulcanized India rubber) wire

used in porcelain cleats. The cleats are of three types, having one, two or

three grooves so as to receive one two or three wires. They are made in

two halves. One is grooved to receive the wire the other is put over it and

the whole is fixed on the wall. The system of installation is cheap and its

most suitable for temporary wiring. It can be easily installed and also

removed quickly when not require.

2) WOOD CASING CAPPING: The system of wiring recommended to be made of

well seasoned teak wood or any other suitable hard wood. It should be free from

knots shakes or any other defect. The casing has usually two grooves to carry

wires. At the top it is covered by a strip known as the capping. The width of the

capping to show position of wires so that the screws may not be driven through

wrong position. Wood gutties are fixed on the wall separated by a distance of not

more than one meter. Round porcelain disc insulator are used between the wood

gutties and casting. The fixing is done with countersunk scores into the gutties.

The capping is screwed over 15cm for all sized up to 6cm. width casings.

3) CTS WIRING: CTS cable tyre sheathed wires are available in single

twin or three cores with a circulars or oval shape. The cable is free the

effects of moisture, acids alkalies and climatic variations. It can be

exposed to sun. The cable can be buried under / sasonary work but is

usually laid over wood battens. The system is even suitable for places

where chemical fumes are present.

4) METAL SHEATHED WIRING: The wire consist of rubber insulated

conductor over which as heath of lead aluminum alloy is provided

externally. This covering provides protection to the cable from

mechanical injury. In residential buildings they are run over wooden

battens. The sheathed should be earthed otherwise electrolytic action may

take place to the leakage of current and there by deteriorate the covering

moreover earthling prevents the metal covering from becoming alive.

These cables are not suitable for places where chemical corrosion may

rise. They effect on the open ends of cable are give; these cable are more

costly than CTS ones.

The following points should be noted when installing metal sheathed wiring.

1. Metal clips and Saddles used to support the cable should be placed 40cm apart.

2. The support used should not be of such a material as to cause chemical action with the sheaths.

3. The icas sheath should be run over a damp place.

4. The cable should be run over the damp place.

5. The cable should be run in conduits when crossing the floor or wall.

6. Sharp bends should be avoided. 7. Conduit wiring: workshop and public building this is the best and most

Desirable system of wiring it provides mechanical protection and

safety against fire. They can be supported over the wall by saddles and

pipe hooks.

Care & Maintenance of Tools:

1. PLIERS: 1) Do not cut steel wires and other hard

substances

2. SCREW DRIVER:

a) The edge should not be too sharp

b) At must fit in the slot of the screw head

c) Do not use it as hammer or chisel

3. POWER:

a) Keep it well sharpened

b) Do not use it on metals

4. GIMLET:

a) It should be kept straight while holes otherwise the screwed portion may

damage.

5. FIRMER CHISEL:

a) Always strike the chisel with mallet

b) Grind it on the water stone and shapen it on the oil stone

c) Do not use it at place where nails are driven in

6. COLD CHISEL:

a) The edge must be properly maintained

b) There should be no trace of oily substance

7. TENON SAW OR HAND X SAW:

a) Keep the teeth sharp with triangular file.

b) Protect from must

c) When not in use apply grease

d) The handle should not be loose

7. DRILLING MACHINE:

a) Keep the machine always clean and lubricants the parts specially the

gears.

b) Drill bit should be properly fixed in the jaws of the machine

c) Keep it perpendicular to the place of the job while making loose.

d) If taper hole is to be made, first make a guide hole with a small bit and

then use a bit of the proper size.

9. SOLDERING IRON:

a) Before soldering an object first time its bit.

b) Clean the rust or dirt with sand paper before applying the soldering iron

c) Soldering should not be cover heated

10. VICE:

a) Vice should not be used as an anvil.

b) It should not be tightened excessively

c) Clean regularly after use.

11. WIRING TOOLS:

1. COMBINATION PLIER: Plier is used for cutting and twisting the

wires. They are specified in length and the range is 15, 20, 25, or 30 cm.

either they are insulated or un insulated. Insulated Plier is particular used

on live wires because the insulation gives protection from shocks.

2. SIDE CUTTING PLIER: It is used for cutting wires and happening the insulation from the . it is widely used for winding works, radio assembling and other delicate instruments.

3. ONG NOSE PLIER: It is used for working in space for holding lightening and loosening small nuts.

4. SCREW DRIVERS: Screwdrivers of different sizes are used for different types

of jobs. They are used for taking out or driving slotted heat screws by

turning them. The size is measured by its blades. A good driver has a

hardened and tempered egde. The edge should not be ground to suit

different screw heads.

5. POKER: it is a pointed tool with flat sides and used for making pibt holes for screws in wood casing boxes etc.

6. GIMLET: It is used for making holes in wooden articles. They are of

different length and different diameters. The diameters various steps of

3mm from 6mm to 25mm.

PINCER: It is used to extract nail and cut conductors.

7. HAND DRILLING MACHINE: It is used for making holes in metal works. Chucks to take drill bits up to 9.5mm. Serve the purpose of an

Electrician.

8. SOLDERING IRON: Electric soldering iron is very solder small joints, terminals, etc., for heavy duty work an iron of high wattage is used such as 125 or 250 watts.

9. STANDARD WIRE GAUGE:A circular plate of steel has a number of slots on

its circumference. The numbers are marked on each slot. Holes are

provided at the end slot for moving the wire easily. To find the gauge of a

wire, the particular slit is found by trail into which a bare wire just slides

without being damaged. The number stamped opposite to the number of

the gauge required.

10. KNIFE: it is folding steel knife, which is very useful for cleaning wires. It should not be used for cutting wires.

11. BRAWL PLUG TOOL: The tool has bits of metal suitable for the job. Usually

they are made of steel the tool bits are numbered according to the size of

plugs used. Their importance lies in wiring concrete and stonewalls. Holes

are made on the walls of sufficient depth and fires plugs are inserted in

them. The material to beheld in position is placed on the plug to expand

and grip the wall. While using

the tool, it should be rotated slowly after each hammering moreover it

Should not be used on the material.

ACCESSORIES:

1. ICDP (Iron Clad Double Pole) switch 15 Amps.

2. SPT (Single polo tumbler) switch 5 Amps.

3. 2-way tuber x switch 5 Amps.

4. Intermediate switch 5 Amps.

5. Batton holder Brass or (Bakelite)

6. Pendant holder (Brass or Bakelite)

7. Slanting or angle holder brass

8. Wall bracket

9. Batton holder MC (Miniature cup )type

10. Wall socket 2 pin 5 Amps.

11. Wall socket 3 Pin 5 Amps

12. 2 Pin plug switch combined

13. Ceiling rose 5 Amps

14. 3 Plate ceiling rose 5 Amps.

15. Junction box or cut 5 Amps.

16. Electric bell 230 volts & bell push switch.

17. Bed room transformer 230 volts. 13.5.8 volts.

18. SWG (Standard wire gauge) used for expressing the size of wires.

19. Kt. Kat 15 Amps.

20. VIR (Vulcanized Indian rubber) wire 1/18

21. CTS (Cable tyre sheathed ) wire 1/16

22. Flexible wire plastic or silk core.

23. Wooden screws 60mm, 50mm, and No.8 for rectangular and round blocks.

24. Wooden screws 30mm no 8 for porcelain cleats 2 ways & 3 ways.

25. Wooden screws 20mm no 5 for tumbles switches ceiling rose cut out power

plug and repair.

26. Wooden screw 12 mm, no 4 for batton holder

27. 2-pin socket wall bracket transformers and wood capping

28. Porcelain cleats 2way and 3 way

29. Wood casing and capping

30. Link clips 45mm, 35,, and 30mm etc.

31. Nails 12mm no 17 for link clips.

32. Bare copper wires, no. 14 SWG

1.EARTHING: In an electric circuit, power passes from positive to the

negative terminal. The Earth is the biggest negative terminal. The tendency

for current is to pass to the earth if a suitable contact/conductor is

available. In an electric circuit ,if there is any gap due to improper

connection, (the air being a poor conductor), current will not flow in

the circuit. Bur of such a circuit having positive potential is touched by a

human being, current will pass through the body into the earth making him

a part of the circuit. Ear thing 2’x2’x4’ for one normal house Human body

gets electric shock proportional to voltage. Higher the voltage, higher the

damage. In many countries like US, Canada etc the domestic voltage is only

110V against the 220 V being used in India. So the danger of shock is prevented in

those countries whereas we have the pro0blem, due to 220 V supply voltage. Ear

thing is a safety device to run an electric conductor in parallel to the circuit

connecting body of the equipment and a third point to the earth. By this in case of

any open circuit accidentally, the current will travel through the earth wire to

earth causing no damage t the person becoming a part of the circuit. It is legally

necessary for all machines and other equipment used in factories.

DEMONSTRATION: Ear thing system/3-pin plug/earth connection

2.FUSE :Fuse is a device to protect electrical equipment against

overloading of its components due to short circuits etc. Every electrical

equipment is designed to with stand certain current rating. If the current

supplied is higher, it will damage the equipment. To prevent such damage

a thin wire of low melting point-alloy of optimum current carrying

capacity is provided near the main switch in the circuit. If due to any short

circuit or voltage fluctuation, the current in the circuit exceeds the limit, the

fuse-wire gets melted (due to low melting point-alloy with which it is made

and the thin dia)breaking the circuit. This saves the electric equipment from

getting spoiled by continuous exposure to such high current.

Precautions: Do not use thick-wire/copper wire for fuse as it allows excess current

into the circuit and causes heavy damage permanently to equipment.

DEMONSTRATION: Types of fuse wire/fuse-holder / cartridge / fuse / replacing a

fuse.

SAFETY PRECAUTIONS FOR AVOIDING ELECTRICAL ACCIDENTS.

IMPORTANT: Electric shock are easily received and avoided. The risk is not always

apparent, be careful. Take no chance.

1. Always switch off the main switch before replacing a blown fuse. 2. Always use correct size of fuse, while replacing blown fuse.

3. Always maintain earth connection in satisfactory condition, safety depends upon good earthling.

4. Beware of live-wires or conductors bare or insulated. 5. Before replaying a lamp or handling a table fan be sure that he switch is

in “OFF” position. 6. Before switching on current to any portable equipment, make sure that

it is properly earthed and insulation is sound. 7. Be sure that all the connections are tight. 8. Before working on inductive circuits or cable discharge them (through

short circuit) or earth. 9. Don’t forget to put on safety belt before starting work on ground level

or pole. 10. Never disconnect a plug point by pulling the flexible wire. 11. Never temper unnecessary with any electrical apparatus unless you are

authorized to handle it. 12. Never touch an over head line unless you sure that it is dead and

properly earthed. 13. Never energies a line unless you are sure that all is clean and there is no

one working on that line. 14. Never temper with electric prospective or inter-locking gearing unless

you are specially authorized for them, taking all precautious. The advices are for your safety only.

15. While handling any portable appliances (table fan etc.) see that it is disconnected from supply, switching “OFF” may not enough, leakage of insulation can give you a serious shock.

16. While working on an motor/Generator (Rotating Machine) make it sure that no one can put it to “ON” position without your permission.

17. When cells are being charged in a room, always maintain good ventilation. Never bring a naked light near a battery.

18. Do not bring a naked light near a battery, Smoking is also prohibited in the battery room.

19. Rubber mattresses are placed in front of electrical panels and switch boards.

20. Do not tie the wire with electric pole. 21. In case of fire:

i) Do not throw water on equipment. It will be very harmful to you, because water is good conductor of electricity.

ii) Disconnect the supply immediately. iii) Do not use a fire extinguisher on electricity unless it is suitable for

that purpose.

22. Use portable insulated hand lamp for testing purpose.

HOUSE WIRING

Excersice-1

AIM: To control one lamp independently with one S.P.T. switch in conduit wiring

according to the given diagram.

ROUTE DIAGRAM CIRCUIT DIAGRAM

S.No. Item Description Quantity Size

1 ¾” P.V.C. Pipe 3 Nos. 51 cms

2 Teak wood round block 7 x 4 2 Nos.

3 Wire 1/18 S.WAG P.V.C. 180 cms

4 Brass button holder 5A 1 No.

5 Tumbler switch one way 5A 1 No.

6 ¾ P.V.C. 3 way Box 1 No.

7 Saddle ¾” 3 Nos.

8

Wooden Screws:

1) 50mm No-8

2 Nos.

2) 20mm No.5 2Nos.

3) 12mm No.4 2Nos.

TOOLS REQUIRED:

S.No. Item Description

1 Tenon Saw size 250 mm

2 Screw driver size 250 mm 828

3 Insulated Cutting Piler

4 Screw driver size 200 mm 937

5 Firmer Chisel size 12 mm

6 Screw Driver size 150 mm 912

7 Drill Machine

8 Ball Pen Hammer 0.25 kg.

9 Drill Bits 6mm & 4mm

10 Poker

11 Knife or Insulation remover.

PROCEDURE:

1) Draw the route diagram of the wiring on the board with chalk. 2) Cut the required length of P.V.C. pipe and fix as per route diagram and by

help of saddle. 3) Cut the P.V.C. wire of the required length and fix in the P.V.C. Pipe

according to circuit diagram. 4) Drill holes around block for wires and fix them in them to the board. 5) Fix the holder on one of the round blocks and the switch on the other. 6) Complete the wiring as per the circuit diagram and check it with mugger

before giving the supply.

PRECAUTIONS:

1) The tools should be used carefully. 2) All the connections should be tight.

HOUSE WIRING

Excersice-2

AIM: make P.V.C. conduit wiring connection to control one lamp with S.P.T. switch

and one 2 pin socket point independently according to given route diagram.

ROUTE DIAGRAM

Circuit Diagram

PROCEDURE:



according to circuit diagram. 4) Drill holes around block for wires and fix them in them to the board. 5) Fix the holder on one of the round blocks and the switch on the other. 6) Complete the wiring as per the circuit diagram and check it with mugger


PRECAUTIONS:

1) The tools should be used carefully. 2) All the connections should be tight.

HOUSE WIRING

Exercise-3

AIM: Make conduit connection in to control one lamp from the different

places with two different places with two different switches according to

given route diagram ( Staircase Wiring).

ROUTE DIAGRAM

CIRCUIT DIAGRAM

PROCEDURE:



according to circuit diagram. 4) Drill holes around block for wires and fix them in them to the board. 5) Fix the holder on one of the round blocks and the switch on the other.

Complete the wiring as per the circuit diagram and check it with mugger


PRECAUTIONS:

1) The tools should be used carefully.

2) All the connections should be tight.

HOUSE WIRING

Exercise-4(a)

AIM: To Control a bell with bell switch in conduit wiring as per the route wiring.

Route Diagram

Circuit Diagram

PROCEDURE:



according to circuit diagram. 4) Drill holes around block for wires and fix them in them to the board. 5) Fix the bell on one of the round blocks and the switch on the other.

Complete the wiring as per the circuit diagram and check it with mugger


PRECAUTIONS:

1) The tools should be used carefully.

2) All the connections should be tight.

Earthing (( Exercise-4(b))

The process of connecting metallic bodies of all the electrical apparatus and

equipment to huge mass of earth by a wire having negligible resistance is called

Earthing

Purpose of Earthing

• To save human life from danger of electrical shock or death by blowing a fuse i.e. To provide an alternative path for the fault current to flow so that it will not endanger the user

• To protect buildings, machinery & appliances under fault conditions ie. To ensure that all exposed conductive parts do not reach a dangerous potential.

• To provide safe path to dissipate lightning and short circuit currents. • To provide stable platform for operation of sensitive electronic

equipments i.e. To maintain the voltage at any part of an electrical system at a known value so as to prevent over current or excessive voltage on the appliances or equipment .

To provide protection against static electricity from friction

Concept of Earthing Systems

All the people living or working in residential, commercial and industrial

installations, particularly the operators and personnel who are in close operation

and contact with electrical systems and machineries, should essentially be

protected against possible electrification. To achieve this protection, earthing

system of an installation is defined,

designed and installed according to the standard requirements..

PLUMBING TOOLS

INTRODUCTION FOR TOOLS OF PLUMBING: Following tools are used in the common

plumbing working up to medium size (10 cm / 100 mm) pipes.

1) Hacksaw

2) Pipe Cutter

3) Pipe Vice

4) Pipe Bending Machine

5) Threading die

6) Ratcher type die holder

7) Pipe wrench

8) Chain-wrench

9) Adjustable wrench

10) Water pump pliers

11) Set the common spanners and ring spanners

1) HACKSAW: It is used for cutting of pipes. Figure 1 shows a hacksaw commonly used, it

essentially consists of a frame, Handle, Prongs, tightening screw and nut. The blade is fixed

in position and tightened by means of the tightening screws.

2) PIPE CUTTING: A pipe cutting is used to cut off the pipes. It has a handle have the length

to a suitable leverage, front position is like the letter C, Three rollers are fixed in it. The

shape of the rollers is convex on both sides. They are made of alloy steel hardened and

tempered. They rotate themselves with friction while moving around the pipe.

3) PIPE VICE: It is a device used to hold the pipe firmly while doing the operations of cutting

threading etc., and while fixing or removing the couplings, the jaws have vee shaped grooves

or steps and they grip the pipe firmly at four corners.

4) PIPE BENGDING MACHINE: Figure, shows a pipe bending machine, hydraulically

operated, It essentially consists of two adjustable bending blocks. The third daily block is

pressed by means of hydraulic jack and bends the pipes according to the requirements.

5) THREADING DIE: This is a cutting tool up of HSS (High Speed Steel) Material and is

used for cutting external threads on pipes. Dies are available in different sizes and each one

will form thread of that specify size i.e., ½” BSP die set can produce ½” BSP threads only.

Dies are fixed in die holder and pipe to be threaded is fixed in pipe vice. Dies are inserted on

to the pipe and die holder is gradually rotated completely till the threads are formed on the

pipe. It is required to check with the help of socket whether thread is completing formed or

not. Die holder has to be rotated in opposite direction for withdrawing the die sets form the

pipe.

6) RATCHET TYPE DIE HOLDER: The ordinary die holder is not suitable for threading the

pipes which are fixed in their position and die holder cannot be completely rotated due to

certain obstructions like wall, other pipes etc in such cases, ratchet type die holder is used. It

can be rotated in the regular direction partially and dies also rotate. It can be rotated in

opposite direction in which ratchet slips and only holder is rotated but not die sets. Again it

can be rotated in regular direction for further threading, like wire thread is completed. For

withdrawing die sets, ratchet position is reversed so that it rotates the die set in the opposite

direction and slips in the regular direction. Thus die sets are withdrawn from the pipe. This is

suitable for cutting the threads where complete & rotation of the die holder is not possible.

7) PIPE WRENCH: Figure shows a pipe wrench commonly used for tightening and

unscrewing of the pipe up to 7 cm diameter pipes. These pipes wrenches are manufactured

from 50 to 60 cm length. The teeth are provided on the jaws to hold the pipe in position and

prevent its slipping while tightening.

8) CHAIN WRENCH: The front portion of the chain wrench is like a triangle and handle is

fixed with it having a chain also. After fixing the chain around the pipe, the chain end is

inserted in a box for locking with a pin, It holds the pipe firmly and it is fit for rotation on

either ways.

9) ADJUSTABLE WRENCH: Figure shows an adjustable wrench pump plier. It is used for

screwing and unscrewing of small diameter pipes. It can also be used in tightening of nuts of

bolts, fixing of small taps, valves, etc, in the pipe lines.

10) WATER PUMP PILER: Figure shows a water pump plier. It is used in house plumbing

work. It is the most tool used in the plumbing work.

11) SET COMMON SPANNERS AND RING SPANNERS: Set of ring spanners and common

spanners are required in the plumbing work for various tightening works of cocks, valves,

etc.

PART FOR PIPE & JOINTS

G.I. (GALVANIZED IRON) PIPES: Pipes are used for carrying fluids such as water, steam,

gas, oil, etc., from one place to another. As pipes are made in standard lengths, and desired

length of a pipe may be obtained by joining them. The type of joint used depends upon the

material of the pipe and purpose for which it is used.

Generally, pipes are made of cast iron, wrought, iron, steel, brass or copper. The material

selection is based on the nature of the fluid to be conveyed, viz., pressure, temperature, chemical

properties, etc. Now a days PVC (Polyvinyl chloride) pipes are extensively used ease for various

purpose.

1) COUPLING: It is a hollow piece having full of threads in the inner side. It is used to

join two pipes of the same diameter on a straight line, on any length of pipes.

COUPLING

2) ELBOW: It is used for changing the direction at right angle by square or round. It has

inner threads in the both ends to a short length. The two pipes are screwed in it is any

length.

ELBOW

3) TEE: (T) It is used to make a branch right angle to the main line. It accommodates three

pipes at any length.

TEE

4) CROSS (T): It is used to speed over the main line on other two opposite direction at

right angle to one another. It accommodates four pipes at any length.

CROSS (T)

5) REDUCER COUPLING: It is used to extend the length in straight line jointing the two

pipes in different diameters in any length.

REDUCER COUPLING

6) PLUG: It is used to block up the pipe on one end. It has a square neck for a spanner to

rotate for tightening or loosening.

PLUG

7) UNION: It consists of three parts. After tightening the pipes on both ends the octogen nut

is tightened. It is used in the pipe line only to separate the connections without disturbing

the pipe line.

UNION 8) FLANGE: It is used for joining the two ends of pipes with bolds and nuts, either in

vertical or horizontal positions it is screwed at one end of the pipe.

FLAN

GE 9) GLOBE VALVE: Where there are many branches, it is fitted for controlling the division

separately. The fluid may be stopped or allowed in any quantity according to the rotation.

GLOBE VALVE

EXPLANATION

PVC SWR Pipes (Polyvinyl chloride, Soil Waste & Rain pipes or (rigid PVC)) & Fittings

have many Advantages over traditional Cement, Asbestos, Cast-Iran (C.I.) Pipes &

Fittings.

Durability & Weather Proof:

PVC SWR (Polyvinyl chloride, Soil, Waste & Rain' or (rigid PVC)) Pipes are made from

“virgin” PVC Material thus resistant to extremes weather conditions, toxic chemicals unlike C.I.

Pipes they are rust & corrosion proof. Cement & Asbestos pipes, have high thermal sensitivity,

which leads to crack & breaking of the pipes PVC SWR Pipes can with stand extreme variations

in temperature.

Dimensional Stability:

PVC SWR(Polyvinyl chloride Soil, Waste & Rain' or (rigid PVC)) Pipes & fittings have

dimensional stability, these are not effected due to external pressure of support, clamps and

fixtures. This also makes possible leakage proof system.

Great Strength & Light Weight:

PVC SWR (Polyvinyl chloride, Soil, Waste & Rain' or (rigid PVC)) Pipes are comparatively

lighter I weight, yet they can with stand high pressure. They can be easily transported, handled

fixed and maintained.

Highly Efficient:

The Smooth & even surface of PVC SWR Pipe (Polyvinyl chloride , Soil, Waste & Rain' or PVC

(rigid PVC) s provides free flow of water, which improves the efficiency of the system.

Resistance:

PVC SWR Pipes are resistant to Oils, Heat and Fire, Fats, Alcohol, Aromatic – Free Patrols and

are more reliable as there is no growth of Fungus, Bacteria, and Termites.

Economical:

PVC SWR Pipes & Fittings prove to be economical on all fronts right from basic cost,

transportation, fixing & maintenance.

Applications:

Homes, Offices, Hotels, Airports, Bus and railway stations.

In mines and vent lines in drainage systems.

In Industries, Chemical Plants, Dairies… as chemical waste lines or overflow lines …….

Distribution of water in agricultural fields…….

EXERCISE 1:

Aim: To cut the given Galvanized Iron (G.I.) Pipe to the required length & perform threading as

per the given sketch.

SKETCH:

MATERIALS REQUIRED:

1) Galvanized Iron Pipe ½

2) Coupling ½

3) Elbow 90° ½

TOOLS REQUIRED:

1) Pipe Threading Die

2) Pipe Cutter & Hacksaw

3) Pipe Wrench

4) Pipe Vice

SEQUENCE:

1) Marking

2) Cutting

3) Threading

4) Testing

5) Finishing and Assembling Socket & Elbow

PROCEDURE:

1) The given G.I. (Galvanized Iron) Pipe is fixed in the pipe vice and cut to the required

length.

2) Die set of suitable size is fixed in the die holder. The two set screws are adjusted such

that the pipe slightly enters into the die set.

3) The die holder is gradually rotated in the clockwise direction completely so that threads

are formed on the pipe up to the required length. The threads so formed are known as

British Standard pipe (BSP) threads in accordance with the die set used. (The thread

length is approximately equal to the die width).

4) The die set is withdrawn from the pipe by rotating the die holder in the counter clockwise

direction.

5) The quality of the threads is tested by fitting the threaded end with a socket. If the two are

not fitted properly, the set screws on the die holder are readjusted & threading is

performed again until the desired results are obtained.

6) The above procedure is repeated on the other side of the pipe & the threads are checked

by fittings with an elbow.

PRECAUTIONS:

1) The die sets are lubricated periodically during threading operation.

2) Over handling of the pipe with die should be avoided.

3) Excessive pressure should not be applied on the die holder.

4) The tools should be handled properly.

EXERCISE 2:

Aim: Pipe cutting threading and fitting as make three way junction TEE EQL with help of Elbow

90° with Bib cock.

SKETCH:

MATERIAL REQUIRED

S. No. Description Quantity

1. GALVANISED IRON PIPE ½” 95 cm

2. Galvanized Iron Tee EQL ½” 1 No

3. Galvanized Iron ELBOW 90° ½” 1 No

4. Galvanized Iron Coupling ½” 1 No

5. BIB Cock & Brass 1 No

Tools Required

S. No. Description

1. Pipe Threading / Ratchet Die

2. Pipe Cutter / Hacksaw

3. Pipe Wrench

4. Pipe Vice

5. Oil Can Cutting Oil

Sequence of Operation

1) Marking 2) Cutting

3) Threading 4) Testing

5) Assembling Tee

Elbow Coupling &

Pipe BIB Cock

6) Finishing

PROCEDURE:

1) First take a long Galvanized Iron pipe and fix it to a pipe vice.

2) Cut the pipe into required length of 15cm, 15 cm, 30 cm, 30 cm with the help of hacksaw,

3) Set the Die Screws of suitable size in the die holder and adjust the two screws.

4) The length of pipe 60 cm is fixed into the pipe vice and the pipe is place into the die

holder and is gradually rotated in the clockwise direction one or two times up to 20 mm.

5) Then a ratchet die is used to get perfect (BSP) external threads.

6) Next a TEE EQL is fixed and checked whether the threads formed are correct.

7) Now at the other end of the pipe threads are formed following the above procedure and a

elbow 90° is fixed.

8) Next take two 30 cms pipes and form threads to both the ends of both the pipes.

9) One end of one pipe is fixed to one side of TEE equal and one end of other pipe is fixed

to other side TEE equal.

10) Now, a pipe of 15 cm is taken and threads are formed on both the ends of the pipes. To

one end a pipe elbow 90° which is connected to 60 cm pipe is connected and to the other

end of tap is connected.

11) All the fitting is performed by using Pipe Wrench.

PRECAUTIONS:


2) Over handling of the pipe with the die should be avoided.



EXERCISE 3:

SKETCH

P.V.C. PIPES LAYOUT OF UNION VALVE

MATERIAL REQUIRED:

1) Galvanized Iron Pipe ½”

2) Galvanized Iron Elbow 90° ½”

3) Galvanized Iron Tee EQL ½:

4) Galvanized Iron Coupling ½”

5) Brass Valve

TOOLS REQUIRED BIB COCK:

1) Pipe Vice


3) Pipe Wrench

4) Pipe Cutter / Hacksaw

5) Oil Can Cutting Oil

SEQUENCE OF OPERATION:

1) Marking

2) Cutting

3) Threading

4) Testing

5) Assembling Shower

6) Finishing

PROCEDURE:

1) First take a long PVC pipe and fix it to a pipe vice.

2) Cut the pipe into required length with the help of hacksaw


4) The length of pipe 120 mm is fixed into the pipe vice and the pipe is place into the die

holder and is gradually rotated in the clockwise direction one or two times up to 20 mm.

5) The ratchet die is used to get perfect (BSP) external threads.

6) Now at the other end of the pipe threads are formed following the above procedure and

an elbow 90° is fixed.

7) Now take one 500 mm pipe and form threads to both the ends of the pipe.

8) One end of the pipe is fixed with TEE, other end of the Tee 150 mm pvc pipe is fixed

along with coupling and the tap. One end of other pipe is fixed to other side TEE.

9) Other end of TEE is fixed with 200 mm pipe and the other end is fixed with gate valve.

10) Attach a 600 mm pipe to the end of the Gate Valve. Other end of the pipe, elbow is fixed.

11) Another 500 mm pipe is fixed with the elbow and the shower is attached to the elbow.

PRECAUTIONS:





EXERCISE 4:

Title or Aim: Difference of Union Joint and Coupling.

Union Joint

1) It consists of Three Pieces.

2) It is used in the region where the Pipes

should not be disturb.

Coupling

1. It consist of one piece

2. Its usage disturbs the pipes in contact

and on either side.

MATERIAL REQUIRED:

1) Galvanized Iron Iron Pipes ¾” / PVC Pipes

2) Galvanized Iron Tee EQL ¾”

3) Galvanized Iron ELBOW 90° ¾”

4) Galvanized Iron Coupling ¾”

5) Galvanized Iron Union Joint ¾”

TOOLS REQUIRED:


2) Pipe Cutter / Hack Saw

3) Pipe Wrench

4) Pipe Vice

5) Oil Can & Cutting Oil.

SEQUENCE OF OPERATION:

1) Making

2) Cutting

3) Threading

4) Testing

5) Assembling

6) Finishing

PROCEDURE:

1) First take a long PVC pipe and fix it to a pipe vice.

2) Cut the pipe into required length with the help of hacksaw.


4) The length of pipe 240 mm is fixed into the pipe vice and threading operation is carried

out.

5) Both end of the pipe is connected with TEE joint and union joint.

6) The length of pipe 220 mm is fixed into the pipe vice and threading operation is carried

out one end pipe is connected with union joint and other is connected with coupling.

7) Take one pipe size of 120 mm which is connected to elbow enter assembly.

PRECAUTIONS:





SHEET METAL WORK

Tin smithy or sheet metal work:

Sheet metal:

Metal in the form of sheet of thickness ranging from 16 gauge to 30 gauge is called sheet metal

Sheet Metal work:

Sheet metal work also known as tin smithy. It is the art of working with sheet metal using hand tools and

simple machines into various forms by cutting, forming into shape and joining.

Sheet metal works deals with working on the metal of 16-30 gauge, with hand tools and simple

Machines. It is one of the major applications in engineering industry. It has its own significance as useful

trade in engineering work. Sheet works such as making a tray, box, funnel, chimney, air duct, fabricate

boiler shells and pipe joints from thin or thick plates, etc. are few examples of its application. For

successful working in the trade, one should have a thorough knowledge of projective geometry and

development of surfaces.

It has its own significance as a useful trade in engineering works and also our day-to-day requirements.

Common examples of sheet metal work are hoppers, containers, guards, covers, pipes, funnels, bends,

boxes etc., such articles are found less expensive, lighter in weight, and at many places they easily

replace the use of castings or forgings.

In sheet metal work to obtain an accurate size and shape of the article from the flat sheet knowledge of

geometry, mensuration and properties of metal is must essential since nearly all patterns come from the

development of the surfaces of member of geometrical models.

Pattern:

It is the flat outline of the object. Is is developed to find the exact amount of sheet

metal required. Patterns are obtained from the development of surface of primitive solids like cylinder,

prism, cone, pyramids using their orthographic projections.

Applications of Sheet Metal:

Sheet metal work is used for making hopper, funnels, various air- conditioning duct, chimneys,

ventilating pipes, machine tool guards, boiler etc. It is also extensively used in major industries like air

craft, manufacturing, ship building, automobile body building and fabrication of duct in air conditioning

equipment etc.,

Principle Involved In Sheet Metal Work:

Generally, all the sheet metal work patterns are based on the development of the surfaces of a number

of geometrical models like prism, cylinder, pyramid and cone. Beside development of surfaces,

geometrical projections are also used for sheet metal work.

General procedure for sheet metal work:

The exact size and shape of the sheet to be cut is given by the development of the surface of the

concerned object. During sheet metal development, cutting lines are scribed by thick lines and folding

lines by thin lines to avoid mistakes during cutting of the sheet.

Development drawn on a flat sheet of metal then the sheet is cut. When cutting larger sheets, allow the

right part to bend down out of the edge of workpiece and pull the left part up to leave space for your

hand to separate the snip.

The cut sheet is folded or rolled with a required shape before the joints are made by welding or any

other form of fastening

Specification of sheet metal:

The sheet is specified by standard gauge numbers each gauge designates a definite thickness.

The gauge number can be identified by standard wire gauge (S.W.G)

The following table shows gauge numbers and their corresponding thick ness of sheet. The

larger the gauge numbers, the lesser the thickness and vice-versa

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

Thickness (mm) 3.2 2.6 2.0 1.6 1.2 0.9 0.7 0.6 0.4 0.3

Materials used in sheet metal work

In sheet metal work, the sheet metal used is black iron, galvanized iron, stainless steel, copper, brass,

zinc, aluminum, tin plate and lead.

Selection of these metals is based up on the type of proses.

Block Iron:

Characteristics:

Less expensive

Uncoated sheet

Bluish black appearance

It can be rolled and annealed

It is less resistant to corrosion

Application:

It is used for making tanks, pans, stove pipes etc which are to be painted or enameled.

Galvanized Iron:

Characteristics:

A sheet of soft steel coated with molten zinc is known as Galvanized Iron

Zinc resist corrosion due to formation of dense layer of corrosion product which

insulates it against continued corrosion.

It resist rust, improves the appearance of the metal.

It is easy to solder but difficult to welding, because zinc gives toxic fumes and

residues.

Application:

It is used for making a pans, buckets, furnaces heating ducks, cabinets etc.

Stainless steel:

Characteristics:

To make the steel resistant to corrosion, chromium-18% and Nickel – 8to 10%

are added to produce stainless steel.

This is an iron based alloy having high resistance to corrosion

It is tough and can be welded easily.

Cost is very high

It is tougher than galvanized iron sheet.

Application:

Domestic appliances such as vessels are made up of stainless steels due to its

effective anti-corrosion property.

It is ideally suited for handling and storage of liquid helium, hydrogen, nitrogen

and oxygen that exist at cryogenic temperature.

Copper:

Characteristics:

It is reddish in colour, malleable and ductile. It is costly metal.

Copper sheet are available as either cold rolled or hot rolled sheets.

It is highly resistance to corrosion

Since it is a ductile material, it can be formed into complex shapes

It can be easily welded, soldered and riveted

Application:

Copper sheet is used in making cutters, expansion joints, roof flashing and hoods,

automobile radiator.

Aluminum:

Characteristics:

It is whitish in color and light in weight.

It con not be used in pure forms but its alloys are used

It is resistant to corrosion and abrasion

Application:

It is used for making household appliances, vessels used in chemical and

food industries.

Tin plate:

Characteristics:

It is a steel sheet coated with pure tin to protect it against rust.

It has a bright silver appearance

The size and thickness of tin plates are denoted by special marks and not by

gauge numbers.

At temperature of 1000C, it can be rolled into sheets are drawn into pipes.

Application:

It is used in making of roofs, food container, dairy equipment’s, furnace fittings cans etc.

Lead:

Characteristics:

It is a soft and week metal having high resistance to corrosion.

Low strength

High coefficient of thermal expansion.

Application:

It is used for lining in the tank, flooring in chemical pants and it is used in battery plates.

Tools used in sheet metal work:

1. Measuring and marking tools.

Steel rule

Folding rule

Circumference rule

Verner caliper

Micro meter

Thickness gauge

Then sheet metal gauge.

Try square

Prick punch

Center punch

Scriber

Divider

Trammel (point set) Bar

Straight edge

Slandered wire gauge

Cutting tools:

a) Chisels: chisels are used in sheet metal work for cutting sheets, rivets, bolts and chipping

operations. Though there are many types of chisels available, round nose chisels and flat chisels

are mostly used for sheet metal work.

b) Snips or Shears: snips or hand shears, varying in length from 200mm to 600mm. 200mm to

250mm ship is most commonly used. In sheet metal work, straight and curved ships are mostly

used

Straight ships: A straight ship has straight blades for straight line cutting and used for cutting along

outside curves and straight lines.

Curved snips or Bend ships: It has curved blades for making circular cuts, it is used for trimming along

the inside curves or cutting along a curvature. This tool is used for cutting thin metal sheets, before or

after marking, according to the jobs, is called snips. The straight snip is used for cutting along outside

curves and straight lines and curved snip or bent snip is for trimming along inside curves.

Bench shear or Hand lever shear: it is used cut sheets up to 6mm thickness. It consists of fixed lower

blade and movable upper blade. The movable blade is operated by the operating handle and leaver

mechanism. Sheet metal may be cut by shearing action. In this, the force is applied through a

compound lever, making it possible to cut sheet metal.

Striking tools:

a) Hammers.

b) Punches.

Hammers: hammers are used to produce shapes in sheet metal by stretching hollowing, leveling,

riveting, strengthening of sheet metal joins etc. The following hammers are mostly used in sheet metal

works. Light weight hammers and mallets are used in sheet metal work. Ballpeen Hammer has a

cylindrical slightly curved face and a ball head. It is a general purpose hammer used mostly for riveting

in sheet metal work. The cross-peen hammer and straight peen hammers are used for folding the sheet

and to work in the corners of the object.

i. Ball peen hammer

ii. Straight peen hammer

iii. Cross peen hammer

iv. Setting hammer

v. Creasing hammer

vi. Raising hammer

vii. Riveting hammer

viii. Soft nylon hammer

ix. Mallet

Mallet:

Mallet is used for bending and folding work. It is called as soft hammer. Generally, it is made of

wood.

b). Punches: punch is used in sheet metal for marking out centers. Punch is used in sheet metal jobs for

punching or deep marking. The following two types of punches are widely used

i. Dot punch

ii. Center punch

Dot Punch – It is used for marking dotted lines. Angle of punching end is 60°.

Centre Punch – It is like a dot punch used to mark the centre of hole before drilling. Angle of punch end

is 90°.

Bending tools:

Pliers: Pliers are mainly used in sheet metal work for bending thee sheet metal to the required shape it

is also used for holding and cutting the sheet metal. The flat nose pliers and round nose pliers are used

in sheet metal work for forming and holding work.

i. Flat nose plier.

ii. Combination plier.

Su

pporting tools:

Stakes: stakes are nothing but sheet metal workers anvils used for bending, hemming, seaming,

forming etc., using hammers or mallet. Stakes are made in different shapes and sizes to suit the types of

operations. A stake consists of a shank and a head or horn. Stakes are nothing but anvils, which

are used as supporting tools and to form, seam, bend or rivet, sheet metal objects. They are made from

wrought iron, faced with steel.

Types of stake:

i. Half-moon stake: It is used to produce circular labs and circular folder seams.

ii. Hatchet stake: It consists of a horizontal sharp straight edge. Used for making straight and sharp

bents.

iii. Funnel stake: It has a tapered round working face. It is used for shaping conical surface and

making wire rings.

iv. Beak horn stake: It has round tapped horn at one end and a square tapped horn on the

opposite side.

v. Creasing stake: It has a tapped square horn with groove slats on one end and a tapped round

horn on the other end.

vi. Pipe stake: It is most suitable for forming pipes and hallow cylindrical surfaces.

Measuring and Marking tools:

Steel rule: It is used for measuring and layout small work. It can measure with an accuracy of upto

0.5mm. It is used to measure and mark dimensions. It is graduated on both sides in millimeters and

centimeters or inches.

Scriber: It is long wire of steel with its one end sharply pointed and hardened to scratch line on sheet

metal for laying out pattern. It is used in sheet metal jobs for circle making. With the divider we can also

do making the parts of the job. This tool is used for making sheet metal jobs.

Steel Square: It is used for checking the right angle of the jobs. It is used for checking square ness of

two surfaces. It consists of a blade made up of steel which is attached to base at 90°.

Divider: It is used for drawing circles or arcs on the sheet metal. They are used to mark a desired

distance between two points and to divide lines into equal parts.

Trammels: It used for marking of arc and circle. Maximum size of the arc that can be scribed depends on

the length of the beam in scriber. It is used to draw large circles and arcs. This is also a marking tool

Sheet metal gauge: It is used to find the thickness of the sheet metal. The various types of gauges are

standard wire gauge, American wire gauge etc. The thickness of sheet metal is referred in numbers

known as Standard Wire Gauge (SWG). The gaps in the circumference of the gauge are used to check

the gauge number

Sheet metal operations:

The major types of operations are given below

1. Shearing

2. Bending

3. Drawing

4. Squeezing

Shearing:

Cutting off: This means shearing of a sheet metal by cutting along a single line.

Parting: It means removable of scrap between the two pieces to part them

Blanking: It means cutting a whole piece form sheet metal

Punching: It means making circular holes on to sheet of metal by a punch and die.

Notching: This is a process of removing metal to the deceived shape from the side or edge of a sheet.

Slitting: It means cutting the sheet metal using rotary blade.

Lancing: Lancing is to make a small cut without any removable of sheet metal.

Nibbing: It means cutting any shape from a sheet metal without special tools.

Trimmimg: It is operation cutting a away excess metal in burs from sheet metal.

Flattening and leveling: It means restoring the metal to its original flatness.

Bending:

It means that the metal is stress 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,

roll forming and seeming.

Drawing: It is the operations of producing cup shaped components from sheet metal by many number

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

calculated pressure from a punch against the blank.

Squeezing: It is the one of the methods of forming ductile materials. Riveting, cold heading and rotary

swaging are very common process of squeezing.

Swaging: Swaging is a molding raise upon the surface of sheet metal.

Hollowing: Hollowing is the process of forming shallow dish or bowl forms. The metal is placed over a

suitable hollow over a wooden block or on a leather covered sand pad and beaten to shape with a

hollowing hammer or mallet.

Stretching or expending: During stretching, contours are generated that are produced from cylindrical

forms.

Flanging: It is process of increasing the width of a job along the edge. That process is carried out by

hammering with the help of stakes and mallets.

Planishing: It is finishing operation. It is done by striking with hammer. Hammer blows are evenly struck

on surface, each blow slightly overlapping the previous one.

Riveting: Rivets are used to joint two or more sheets of metal together. Round rivets, conical rivets, flat

rivets and counter sunk rivets are commonly used in the sheet metal work.

Sheet metal joints: Sheet metal working incorporates a wide variety of hems and seams.

Hem: Hem is an edge or border made by folding.

Types of Hem:

a) Single hem: It is made by folding the edges of the sheet metal over to make it smooth and stiff.

b) Double hem: It is made by folding the edges over twice to make it smooth and stiff.

c) Wider hem: Edge of the sheet metal is rolled to some distance. It is smooth and very strong.

Seam: A seam is a joining made by fastening two edges together.

Types of seam:

a) Single seam: It is used to join a bottom to vertical bodies of varies shapes.

b) Double seam: It is similar to single seam but its formed edge is bent upward against the body.

c) Grooved seam: It is made by holding two single hems together and locking them by a groover.

Exercise No.1

Aim: To make a rectangular tray from a given metal sheet

Sketch: As shown in Figure

Material Required: G.I. Sheet 22 gauges and M.S. rivets flat head 6 mm dia x 6 mm length

Tools Required

1. Steel Rule

2. Try Square

3. Scriber

4. Divider

5. Prick Punch

6. Solid Punch

7. Snips

8. Wooden mallet

9. Ball peen hammer

10. Hatchet stake

11. Leveling plate

12. Rivet set

13. Bevel Protractor

Sequence of Operations

1. Measuring/checking

2. Leveling

3. Marking

4. Cutting

5. Folding/ Bending

6. Hemming

7. Riveting/ Soldering

8. Dents removing

9. Checking Final Dimensions

Procedure:

1. The size of the given sheet is checked for its dimension using steel rule.

2. Then the sheet is leveled on the leveling plate using a mallet.

3. The development procedure is followed the same as the square taper tray.

4. The dimensions are marked as shown in figure.

5. The sheet is cut as per the marked dimensions by straight snips.

6. Then a single hemming is made on the four sides of the tray as shown in figure.

7. The four sides of the tray bent to 90_ using the stakes anvil.

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

Precautions:

1. Use hand leather gloves while handling heavy sheets.

2. Avoid pulling the cut portion by hand while cutting with snip.

3. After performing the work wash hands thoroughly because the fluxes and solders containing

material should not enter into the stomach.

Result: Thus desired rectangular tray is made from the given sheet metal.

Exercise No.2

Aim: To make a rectangular scoop from given G.I. Sheet


Material Required: G.I. Sheet 24 gauges, M.S. rivets flat head 6 mm dia x 6 mm length

Tools Required

1. Steel Rule

2. Try Square

3. Scriber

4. Divider

5. Prick Punch

6. Solid Punch

7. Snips

8. Wooden mallet

9. Ball peen hammer

10. Hatchet stake

11. Leveling plate

12. Rivet set




2. Leveling

3. Marking

4. Cutting

5. Folding/ Bending

6. Hemming


8. Dents removing


Procedure:

1. Take a G.I sheet of required length, breadth as per specification

2. Sheet is leveled on the leveling plate using a mallet

3. Check the given sheet for correct dimensions by using steel rule.

4. Mark the sheet as per the given specification with help of steel rule, try-square, scriber and prick

punch (or) Take the top sheet and mark the lines according to the dimensions as shown in figure.

5. Cut the sheet with the help of straight snip along the cutting line (or) Remove the excess material

as shown hatched portion in the figure with the help of straight snip.

6. Bend the four corners of the sheet through 900 with the help of a beak horn stake then single

hemming is made on the four sides of the tray as per the dimensions given in the figure

7. Use solid punch for making holes for the purpose of riveting

8. Rectangular scoop is riveted using rivets and hammer

Precautions:





Result: Thus, the required rectangular scoop is made as per the drawing.

Exercise No.3

Aim: To make a square tin box/ cube box closed at one end from given G.I. Sheet


Material Required: G.I. Sheet 22 gauge.

Tools Required

1. Steel Rule

2. Try Square

3. Scriber

4. Divider

5. Prick Punch

6. Solid Punch

7. Snips

8. Wooden mallet

9. Ball peen hammer

10. Hatchet stake

11. Leveling plate

12. Rivet set




2. Leveling

3. Marking

4. Cutting

5. Folding/ Bending

6. Hemming


8. Dents removing


Procedure:

1. Take a G.I sheet of required length, breadth as per specification

2. Check the given sheet for correct dimensions by using steel rule.

3. Mark the sheet as per the given specification with help of steel rule, try-square, scriber and prick

punch (or) Take the top sheet and mark the lines according to the dimensions as shown in

figure.

4. Development of the body of the box is cut, unwanted material is removed using snips. Now

shape of the vertical size of box is obtained.

5. Layout of Base of the box is drawn and cut it.

6. Flanges are formed on the body to receive the base, using stakes and mallet and base of the box

is folded as shown in figure.

7. Base and body are placed in position and folded, using single and double seams.

8. Seams are soft soldered to make the box water tight.

PRECAUTIONS:

1. Take care from any injuries

2. Take care for close measurements while marking and cutting.





RESULT: Finally a square tin box/ cube box is prepared successfully.

Viva – Voce Questions

1. Describe the process of sheet metal work

2. What are the articles that are normally made of sheet metal?

3. Sheet metal layout is know as

4. The hammer is used to shape sheet metal is known as --------

5. What are stakes? Name the different types

6. ------------ are used to support the sheet while shaping

WELDING

Welding is a materials joining process which produces coalescence of materials by heating them to

suitable temperatures with or without the application of pressure or by the application of pressure

alone, and with or without the use of filler material. Welding is used for making permanent joints. It is

used in the manufacture of automobile bodies, aircraft frames, railway wagons, machine

frames,structural works, tanks, furniture, boilers, general repair work and ship building.

TYPES OF WELDING:-

1. Plastic Welding or Pressure Welding

The piece of metal to be joined are heated to a plastic state and forced together by external

pressure

Example:- Resistance welding

2. Fusion Welding or Non-Pressure Welding

The material at the joint is heated to a molten state and allowed to solidify

Example:- Gas welding, Arc welding

Classification of welding processes:

(1). Arc welding

a) Carbon arc welding

b) Metal arc welding

c) Metal inert gas welding

d) Tungsten inert gas welding

e) Plasma arc welding

f) Submerged arc welding

g) Electro-slag welding

(2). Gas Welding

a) Oxy-acetylene welding

b) Air-acetylene welding

c) Oxy-hydrogen welding

(3). Resistance Welding

a) Butt welding

b) Spot welding

c) Seam welding

d) Projection welding

e) Percussion welding

(4). Thermit Welding

(5). Solid State Welding

a) Friction welding

b) Ultrasonic welding

c) Diffusion welding

d) Explosive welding

(6). Newer Welding

a) Electron-beam welding

b) Laser welding

(7). Related Process

a) Oxy-acetylene cutting

b) Arc cutting

c) Hard facing

d) Brazing

e) Soldering

Arc welding methods

1. Metal arc welding

It is a process of joining two metal pieces by melting the edges by an electric arc. The electric arc

is produced between two conductors. The electrode is one conductor and the work piece is another

conductor. The electrode and the work piece are brought nearer with small air gap. (3mm app.)

When current is passed an electric arc is produced between the electrode and the work piece.

The work piece and the electrode are melted by the arc. Both molten piece of metal become one.

Temperature of arc is about 4000°c Electrodes used in arc welding are coated with a flux. This flux

produces a gaseous shield around the molten metal. It prevents the reaction of the molten metal with

oxygen and nitrogen in the atmosphere. The flux removes the impurities from the molten metal and

form a slag. This slag gets deposited over the weld metal. This protects the weld seam from rapid

cooling. Fig.1 shows arc welding process.

Fig. 1 Arc Welding

Equipments:(Refer Fig 2)

A welding generator (D.C.) or Transformer (A.C.)

Two cables- one for work and one for electrode

Electrode holder

Electrode

Protective shield

Gloves

Wire brush

Chipping hammer

Goggles

Fig 2 Electric

Arc Welding Equipments

Advantages

Most efficient way to join metals

Lowest-cost joining method

Affords lighter weight through better utilization of materials

Joins all commercial metals

Provides design flexibility

Limitations

1. Manually applied, therefore high labor cost.

2. Need high energy causing danger

3. Not convenient for disassembly.

4. Defects are hard to detect at joints.

2. Carbon arc welding

In carbon arc welding, the intense of heat of an electric arc between a carbon electrode and

work piece metal is used for welding. DC power supply is used. The carbon electrode is connected to

negative terminal and work piece is connected to positive terminal, because positive terminal is hotter

(4000°c) than the negative terminal (3000°c) when an arc is produced. So carbon from the electrode will

not fuse and mix up with the metal weld. If carbon mixes with the weld, the weld will become weak and

brittle. To protect the molten metal from the atmosphere the welding is done with a long arc. In this

case, a carbon monoxide gas is produced, which surrounds the molten metal and protects it.Carbon arc

welding is used to weld both ferrous and non ferrous metals. Sheets of steel, copper alloys, brass and

aluminium can be welded in this method.( Refer Fig 3)

Fig 3 Carbon Arc Welding

Comparison of A.C. and D.C. arc welding

S.No Alternating Current (from Transformer) Direct Current (from Generator)

1 More efficiency Less efficiency

2 Power consumption less Power consumption more

3 Cost of equipment is less Cost of equipment is more

4 Higher voltage – hence not safe Low voltage – safer operation

5 Not suitable for welding non ferrous metals suitable for both ferrous non ferrous metals

6 Not preferred for welding thin sections preferred for welding thin sections

7 Any terminal can be connected to the work

or electrode

Positive terminal connected to the work

Negative terminal connected to the electrode

GAS WELDING

Oxy-Acetylene welding

In gas welding, a gas flame is used to melt the edges of metals to be joined. The flame is

produced at the tip of welding torch. Oxygen and Acetylene are the gases used to produce the

welding flame. The flame will only melt the metal. A flux is used during welting to prevent oxidations

and to remove impurities. Metals 2mm to 50mm thick are welded by gas welding. The temperature

of oxyacetylene flame is about 3200°c. Fig 3 shows Gas welding equipments.

Gas Welding Equipment

1. Gas Cylinders

2. Regulators

Working pressure varies depends upon the thickness of the work pieces welded.

3. Pressure Gauges

4. Hoses

5. Welding torch

6. Check valve

7. Non return valve

Fig- 4 Gas Welding Equipment

TYPES OF FLAMES

When acetylene is burned in air, it produces a yellow sooty flame, which is not enough for

welding applications

Oxygen is turned on, flame immediately changes into a long white inner area (Feather)

surrounded by a transparent blue envelope is called Carburizing flame (30000c)

This flames are used for hardening the surfaces

Addition of little more oxygen give a bright whitish cone surrounded by the transparent blue

envelope is called Neutral flame (It has a balance of fuel gas and oxygen)

Most commonly used flame because it has temperature about 32000c

Used for welding steels, aluminium, copper and cast iron

If more oxygen is added, the cone becomes darker and more pointed, while the envelope

becomes shorter and more fierce is called Oxidizing flame

Has the highest temperature about 34000c

Used for welding brass and brazing operation

Fig 5: Types of Gas Flames

Advantages

1. Equipment has versatile

2. Same equipment can be used for oxy acetylene cutting and brazing by varying the torch size

3. Heat can controlled easily

Disadvantages

1. Slower process

2. Risk is involved in handling gas cylinders

GAS CUTTING

• Ferrous metal is heated in to red hot condition and a jet of pure oxygen is projected onto the

surface, which rapidly oxidizes

• Oxides having lower melting point than the metal, melt and are blown away by the force of the

jet, to make a cut

• Fast and efficient method of cutting steel to a high degree of accuracy

• Torch is different from welding

• Cutting torch has preheat orifice and one central orifice for oxygen jet

• PIERCING and GOUGING are two important operations

• Piercing, used to cut a hole at the centre of the plate or away from the edge of the plate

• Gouging, to cut a groove into the steel surface

Fig 6 Automatic Gas Cutting

Fig 7 Manual Gas Cutting

Weld joint

There are 5 basic joint types in welding

• Butt joint: Two materials are in the same plane, joined from the edges.

• Corner joint:The corners of two materials form a right angle and joined.

• Lap joint: Two parts overlaps.

• Tee joint: One part is perpendicular to the other, making a T shape.

• Edge joint: Edges of the two materials joined.

Types of weld

1. Fillet weld: Used in T joints,corner joints, lap joints.

2. Groove weld:Used in butt joints.

3. Plug weld: Used in lap joints.

4. Slot weld: Used in lap joints.

5. Spot weld: Used in lap joints.

6. Seam weld: Used in lap joints.

7. Flange weld:Used in edge joints.

8. Surfacing weld:Not a joining process, it is used to increase the thickness of the plate, or provide

a protective coating on the surface.

Fig 8 Types of Weld Joints

Weldability is the ease of a material or a combination of materials to be welded under fabrication

conditions into a specific, suitably designed structure, and to perform satisfactorily in the intended

service

Brazing and Soldering

Brazing

It is a low temperature joining process. It is performed at temperatures above 840º F and it

generally affords strengths comparable to those of the metal which it joins. It is low temperature in that

it is done below the melting point of the base metal. It is achieved by diffusion without fusion (melting)

of the base

Depending upon the method of heating, brazing can be classified as

1. Torch brazing

2. Dip brazing

3. Furnace brazing

4. Induction brazing

Fig 9 Brazing

Advantages

Dissimilar metals which canot be welded can be joined by brazing

Very thin metals can be joined

Metals with different thickness can be joined easily

In brazing thermal stresses are not produced in the work piece. Hence there is no distortion

Using this process, carbides tips are brazed on the steel tool holders

Disadvantages

Brazed joints have lesser strength compared to welding

Joint preparation cost is more

Can be used for thin sheet metal sections

Soldering

It is a low temperature joining process. It is performed at temperatures below 840ºF for

joining.

Soldering is used for,

• Sealing, as in automotive radiators or tin cans

• Electrical Connections

• Joining thermally sensitive components

• Joining dissimilar metals

Fig. 10 Soldering

SAFETY PRECAUTIONS:-

1. Check workspaces and walkways to ensure that no slip/trip hazards are present

2. Check switchgear and cable are in sound condition

3. Check electrode points are in good condition and meet exactly

4. Ensure electrodes are securely mounted and clean from contaminants

5. Gloves should be used to position and hold work

6. When oxyacetylene gas welding or cutting, never leave a lit torch around when it is not in

the welder‟s hand.

7. When oxyacetylene gas welding or cutting, never point the torch at cylinders, regulators,

hose, or anything else that may be damaged and cause a fire or explosion.

8. Before arc welding or cutting, ground the electrical equipment to reduce the risk of the

transformer causing a fire by triggering the electrical supply circuit protection.

9. Always turn off the machine when leaving the work.

10. Apply eye drops after welding is over for the day, to relieve the strain on the eyes.

11. While welding, stand on dry footing and keep the body insulated from the electrode, any other pa

rts of the electrode holder and the work

Fig. 11:- Safety wears

Excersice-1

Single V- Butt joint

AIM: To make a single v-butt joint ( ), using the given two M.S pieces and by arc welding .

TOOLS AND EQUIPMENT REQUIRED: Rough and smooth files, protractor, arc welding

machine(transformer type), mild steel electrode and electrode holder, ground clamp, tongs, face shield,

apron and chipping hammer.

Figure 1: single v-butt joint

SEQUENCE OF

OPERATIONS

1. The given M.S pieces are thoroughly cleaned of rust and scale.

2 .One edge of each piece is beveled, to an angle of , leaving nearly of the flat thickness, at

one end

3. The two pieces are positioned on the welding table such that, they are separated slightly for better

penetration of the weld.

4. The electrode is fitted in the electrode holder and the welding current is set to a proper value.

5. The ground clamp is fastened to the welding table.

6. Wearing the apron and using the face shield, the arc is struck and holding the two pieces together;

first run of the weld is done to fill the root gap.

7. Second run of the welding is done with proper weaving and with uniform movement, during the

process of welding, the electrode is kept at to from vertical and in the direction of welding.

8. The scale formation of the weld is removed by using the chipping hammer.

9. Filling is done to remove any spatter around the weld.

RESULT: The single v-butt joint is thus made, using the tools and equipment as mentioned above.

Excersice-2

Lap Joint

AIM: To make a lap joint, using the given two M.S pieces and by arc welding .




Figure 2: Lap joint

SEQUENCE OF OPERATIONS

1.Take the two mild steel pieces of given dimensions and clean the surfaces thoroughly from rust, dust, particles, oil

and grease.

2. Remove the sharp corners and burrs by filing or grinding and prepare the work pieces.

3. The work pieces are positioned on the welding table, to form a lap joint with the required over lapping.

4.The electrode is fitted in to the electrode holder and the welding current is set to a proper value.


6.Wearing the apron, hand gloves, using the face shield and holding the over lapped pieces the arc is struck and the

work pieces are tack‐welded at the ends of both the sides

7.The alignment of the lap joint is checked and the tack‐welded pieces are reset, if required.

8. Welding is then carried out throughout the length of the lap joint, on both the sides.

9. Remove the slag, spatters and clean the joint.

RESULT: The lap joint is thus made, using the tools and equipment as mentioned above.

Exercise-3

T- Joint

AIM: To make a T- joint, using the given two M.S pieces and by arc welding .




Figure 4: T- joint


1. Take the two mild steel pieces of given dimensions and clean the surfaces thoroughly from rust, dust particles, oil and grease.

2.Remove the sharp corners and burrs by filing or grinding and prepare the work pieces. 3. The work pieces are positioned on the welding table such that, the T shape is formed.



6.Wearing the apron, hand gloves, using the face shield and holding the pieces the arc is struck and the work pieces are tack‐welded at both the ends.

7.The alignment of the T joint is checked and the tack‐welded pieces are reset, if required.

8.Welding is then carried out throughout the length of the T joint as shown in the figure.


RESULT: The T-joint is thus made, using the tools and equipment as mentioned above.

Excersice-4

Corner Joint

AIM: To make a corner joint, using the given two M.S pieces and by arc welding .




Figure 3: Corner joint


1.Take the two mild steel pieces of given dimensions and clean the surfaces thoroughly from rust,

dust particles, oil and grease.

2. Remove the sharp corners and burrs by filing or grinding and prepare the work pieces.

3. The work pieces are positioned on the welding table such that, the L shape is formed.



6. Wearing the apron, hand gloves, using the face shield and holding the pieces the arc is struck and

the work pieces are tack‐welded at both the ends.

7. The alignment of the corner joint is checked and the tack‐welded pieces are reset, if required.

8. Welding is then carried out throughout the length.


RESULT: The corner joint is thus made, using the tools and equipment as mentioned above.