workshop manual 2011 2012

PATEL COLLEGE OF SCIENCE AND TECHNOLOGY, INDORE /BHOPAL

MECHANICAL ENGINEERING DEPARTMENT

LABORATORY MANUAL

Workshop Practice Semester -I & II

(BE-207)

Prepared By:

RAJMOHAN THAKUR(Workshop Superintendent)

Student Name ……………………………………......................

Roll No.… ………………………………………………………

Branch……………………….Batch…………………….………

Session………………………………… Semester …………..…

Website: www.patelcollege.com

Mechanical Engineering Department 1


WORKSHOP PRACTICE - 207

(BE-207)



PRACTICAL RECORD

SignatureWorkshop Superintendent(Mechanical Engineering)

SignatureH.O.D.

(Mechanical Engineering)

INDEX


Carpentry Shop

JOB NO. Date of startDate of

comlpetionTotal

AttendanceLab incharge

remark

1

2

3

Welding Shop

JOB NO. Date of start Date of comlpetion

Total Attendance

Lab incharge remark

1

2

3

FittingShop

JOB NO. Date of start Date of comlpetion

Total Attendance

Lab incharge remark

1

2

3



S.N. OBJECT SUBMISSION REMARK

01 Precautions of Mechanical Workshop.

02To study the various tools and operations in carpentry shop.

03To study the various tools and operations in welding shop.

04

To study the various tools and operations in Fitting shop.

05

To study the various tools and operations in smithy and forging welding shop.

06

To study the various tools and operations in Foundry shop.


PRECAUTIONS OF MECHANICAL WORKSHOP

1. Loose clothing should always be avoided.

2. Shoes with thick sole should always be wear in the workshop.

3. Don’t wear rings, watches & other jeweler to catch.

4. Wear shirts with half skives &rolled above the elbow properly.

5. Get the first aid immediately in case of injury.

6. Do not allow any other person to stand with you when you are working on machine.

7. Do not operate any of the machine or tools until you know about the operation.

8. Do not use tools as toys.

9. Avoid taking cut engines the direction of grain.

10.While working on the lathe the job should be properly between the centre of tools should be held, formally use goggles.

11.No one may use the power equipment or portable power tools (jig saws, circular saws etc) we don’t permission of supervision.

12.No one may use the power equipment we don’t permission of the workshop supervision.

13. If the specialist training or certification is needed to work machinery, it must be obtained before use.

14.Workshop machinery must be regularly maintenance.

15.Safety guards fitted to machine tools, laboratory apparatus & other potential hazards must never be removed, except in the event of a break down or maintenance.

16. In an emergency: press any of the emergency stop buttons to cut the power equipment.



CARPENTRY SHOP

Aim To study the various tools and operations in carpentry shop. Theory CARPENTRY Is a common term used with any class of work with tools. It deals with the constructional work such as making roofs, floors, partitions etc. of a building by means of wood with the help of carpentry tools.

JOININERY The term joinery is used for connection of wooden parts with the help of different joints such as making of doors, windows, stairs etc. & all the interior fitments of a building.

TIMBER The basic material used for any class of wood working. The term timber is applied to trees which provide us wood. Wood is having good machining characteristics and can easily be planned, sawed &transported.

STRUCTURE OF WOOD The trees are known as outward growers, the layers are termed annual rings, because most of the trees produce one ring each year. Due to rapid growth of spring wood in spring, a thinner denser later is called autumn wood. In spring the outer rings of tree known as sapwood take watery sap from the roots up to the leaves. This sap lies in the form of various starchy, secretions, glues, or resins. These substances full up the tissues feed the tree & help to form a dinner of wood known as HEARTWOOD. The heart wood deals as long as the growth of tree is concerned. The cambium layer is

responsible for the formation of new wood each year. Each year the sapwood becomes transformed into heartwood.

SEASONING OF WOOD The seasoning of timber is the process of draying or reducing the moisture or sap present in freshly felled trees under controlled conditions. The following methods are most commonly used in seasoning of timber. 1. Natural seasoning 2. Artificial seasoning



1. NATURAL SEASONING In this method the trees stacked under cover with spaces in between, so that a free circulation of air can be provided all around them. A further period of seasoning takes place after trees sawn-up & converted into planks/ boards. 2. ARTIFICIAL SEASONING In this method the period of seasoning is very much reduced. The timber is stacked on a special truck wheeled in a special room the room then be sealed. Hot air is circulated in room by fans & certain amount of return is allowed in order to retain correct humidity.

COMMON DEFECT IN TIMBER

1 Seasoning defects 2 Natural defects

3 Defects due to destructive agents 4 defects due to manufacturing / cutting

SEASONING DEFECTS Shrinkage during seasoning takes place in timber, shrinkage in length is negligible but it is more propound in the direction of the annual rings. The timber stored after felling the tree will also undergo the above shrinkages many slow radial splits in dry & hot environment, due to uneven drying during seasoning the timber may wrap or twist.

NATURAL DEFECTS Heart shakes are single splits accruing in the standing tree & can not be seen till the tree is felled. Another. Type of such shakes radiation from with as known as star shakes. Pitch is another defect in the timber when resinous materials accumulate within the wood.

DEFECTS DUE TO DESTRUCTIVE AGENTS These defects include worm holes & fungi-delay. Worm holes in the wood occurred by insects boring through wood.



DEFECTS DUE TO MANUFACTURING / CUTTING

Some of the common manufacturing defects are as follows:-CROSSGRAINMACHINE BURN

CROSS GRAINIt is defined as wood in which the cells / fibers run at an

angle with the axis or sides of the piece. MACHINE BURN Machine burn is usually caused by planner blades that are dull & can be seen along the face of the boards.

CLASSIFICATION OF DEFECTS 2.1 knots, 2.2 shakes, 2.3 irregularities, of wood structure & abnormal colorization of wood, 2.4 defects acquired by fungi, 2.5 defects caused by insects, 2.6 sawing defects & deformation. Each of the classes is further divided in subclasses & each of the subclasses is divided in sub – subclasses.



COMMON VERITIES OF INDIAN TIMBER

BABUL Is the pale red to brown in colour, close grained, hard & thought, but elastic, & takes a good polish.

MAHOGANY The wood is red brown in colour, very durable when kept dry.

MANGOThe wood is a inferior quality, coarse & open grained & of deep gray colour.

SALThe wood is of a dark brown colour, hard, close-grained heavy resistant white ENT & durable.

SISSUEThe wood is dark brown in colour, tough durable, & has coarse grains.

TEAKThe wood is brown in colour, straight grained, & very strong & durable.



CARPENTRY TOOL

HOLDING & SUPPORTING TOOLS :- Bench vice Bench slopT - Clamp G - ClampCarpentry vice

MARKING & MEASURING TOOLS:- Stainless steel rule

Try square Miter square Bevel square Mortise gauge

Marking gauge Cutting gauge Scriber

CUTTING TOOLS:-SawRip sawCrosscut sawTenon sawDovetail sawFirmer chiselMortise chiselBeveled edge chiselAxe

PLANNING TOOLS:-Wooden jack planner

Metallic jack plannerRebate plannerPlough planeSpoke shaveBlock planeRouterHollow & round planeSmoothing plane

BORING & MISCELLANEOUS TOOLSAugerRatchet braceWheel braceScrew driverGimlet



MARKING & MEASURING TOOLS

RULESRules are of various types & designs are used by wood workers for

measuring & setting out dimensions, but they usually work with a four fold rule ranging from 0 to 60 cm.

TRY SQUAR It is used for testing & drawing right angle on work piece. It has

steel blade and wooden/steel stock.

GAUGES Gauges are used to mark lines parallel to the edge of a piece of

wood.

MARKING GUAGE has one marking point. it gives an accurate out line parallel to a tree edge, usually with grains.

MORTISE GAUGE has two marking points one fixed near to the end of the steam & other attached brass sliding bar.

CUTTING GAUGE has a cutting knife held in position by a wedge so that its projection may be varied for the depth of the cut.



CUTTING TOOLS

SAW Is probably the most abused of woodworking tools, chiefly because

inexperienced users force it too much. A saw is generally specified by the length of its blade measured along the toothed edge & pitch of teeth expressed in millimeters.

RIP SAW

Is used for cutting along the grain of wood. Its blade is about 700 m.m. long. The teeth are pointed backside.

CROSS CUT SAW It is used for cutting across & also for general sawing. The

blade is 500 to 700 m.m. long the teethes are pointed front side.

DOVETAIL SAW It is first a small Tenon saw having 200 – 300 m.m. length

the blade is thinner & narrower than that of Tenon saw. It is used forming dovetail joints.

CHISEL Wood chisels most commonly in use includes firmer chisel, mortise

chisel, beveled edge chisel, inside gouge out side gouges. They are usually specified by length of the blade. PLANESThe planes in general use are the jack plane, trying plane, smoothing plane, rebate plane, spoke shave, grooving plane etc.

JACK PLANE consists a body or block made of wood. The bottom face is called sole. It is provided with double iron known as cutting iron or blade, made of circular cast iron. Another is known as back iron, helps to support & strengthen the cutting blade. The irons are fixed at 45ºto the sole, by means of the wedge, made of wood.

METAL PLANE are more durable & produce high degree of finish. The body is made of cast steel or run metal malleable iron. It is provided with a wooden or plastic handle at the back &knob at the front for holding it with hands. It is also provided with a cutting iron.



STRIKING TOOLS

Striking tools include hammers & mallets.

HAMMER In deferent works deferent type of hammers are used engineers use ball pined hammer woodworkers use cross pined & cross pined hammers.

BALL PEEN HAMMER is mostly used for bench work & all right jobs. The head is of cast steel, the face & peen being tempered. These hammers are identified by size no. & weight.CLAW HAMMER is frequently used by carpenter. It is made of cast steel. The head is used to drive nails & the claw is used to remove the nails from the wood. The size of the hammer is designated by the weight & it is available from 150 gm. to 750 gm.

MALLET is made of hard wood these are used to strike cutting tools which have wooden handle such as chisels the head has an eye for striking & the handle to hold it comfortably.



HOLDING TOOLS

BENCH VICE is a very important in all the holding tools. It have two jaws one is one is fixed to the side of the table while the other is kept movable by means of a screw & a handle. The whole vice is made of iron or steel, the jaws being covered by the hard wood face which can be renewed as required.

MISCELLANIOUS TOOLS

RASPS & FILES these are used to cleaned up same curved surface. For instance certain curves & sleeps are too small that the spoke shave can’t enter them and here a file is invaluable scratches left by the file can be removed with the scraper & glass paper several tools are introduced each of which acts either like a chisel or small plane. PINCER the pincer is used for pulling out nails, locks etc., it consists of two arms one arm has a ball and & the other arm has a claw end for levering out the small nails SCREW DRIVER screw drivers are used for screwing or unscrewing screws used in wood work. These may be obtained in various shapes.

SETTING & SHARPENING OF TOOLS

SAWS are reset by slightly bending each tooth, the first tooth is bended one side & the next is apposite side and so on. The amount of set depends upon the types of work being done that the teeth have.



CARPENTRY JOINTS

Constructional woodwork can be divided in to two main classes FRAME WORK & CORNER WORK. The various types of these joints are mentioned below.

HALVING JOINTSThe aim of these joints is to secure the corner & intersections of the framing & at the same time keep all face flush, that is in the same place. The halving joint also termed as a half lapped joint, may be usefully employed in many types of framing where strength & appearance are of secondary consideration. Halving joints are of various types such as corner halving joint, dovetail halving joint, T – halving joint, cross halving joint,

MORTISE & TENON JOINTThis joint is mostly used by wood workers while making doors, windows and also in partition work. This joint is used because of the strength which is most desired in wood work.

BRIDLE JOINT This form of joint is really the reverse of the mortise & tenon joint also known as open mortise & tenon joint.

MITRE JOINT Is used in framing work, in these joints tow wood pieces are cut down at 90º angle then they are fixed by the help of nails &/or gum. These joints are of many types such as mitre joint, tongued mitre joint, etc.



WELDING-SHOPOBJECT

To study various equipments and operation electric arc welding and gas welding.

INTRODUCTION

Welding is process of joining similar metals by application of heat or without application of process and addition of filter material. The result is a continuity of homogenous material, of joined together.

WELDABILITY

The term “Weldability” has been defined as the capacity of being welded into inseparable joints having specified properties such as definite weld strength, proper structure etc.

Weldability depends on one or more of five major factors is [i] Melting Point [ii] Thermal conductivity [iii] Thermal Expansion [iv] Surface condition [v] Change in Microstructure.

ELECTRIC ARC WINDING

The Arc winding is a fusion welding process in which the welding heat is obtained from an electric arc between the work [or base metal] and an electrode. The temperature of heat produced by the electric arc is of the order of 6000 C to 7000 C.

The arc column is generated between an anode, which the positive pole of DC power supply and cathode. When these two conductor of an electric circuit arc through to gather and separated for a small distance such that the current continuous to flow through a path of ionized particles called plasma, an electric arc is formed. Two third of the head is developed near the positive pole while the remaining one third is developed near the negative pole.

The blast of the arc forces the molten metal out of the part, thus forming a small depression in the parent metal, a round which molten metal is piled up. This is known as the “ arc crater” the distance through the centre of the arc from the tip of the electrode to the bottom of the arc creator is term “arc length”.



TERMS USED IN ARC WELDING PROCESS

1. Arc welding: The arc welding is a fusion welding process in which welding heat is obtained from an electric arc between work and an electrode.

2. A.C. welding: In a.c. welding, there is no fixed polarity at the terminals and they interchange in every cycle. The a.c. current also acquires zero value twice in each cycle. Thus at these particular moment, the potential difference between the terminal is zero and hence high voltage is required to maintain the arc at this moment.

3. D.C. welding: The direct current supply for arc welding is usually obtained from a generator driven by either an electric motor or petrol or diesel engine. The positive pole of d.c. generator is connected to work and negative to the base material.

4. Straight polarity: When the work is connected to the positive terminal of a d.c. welding machine and the negative terminal to an electrode holder the welding setup is said to have “STRAIGHT POLARITY”.

5. Reverse polarity: When the work is connected to negative and the electrode to the positive terminal then the welding setup is said to have “REVERSED POLARITY”.

6. Arc blow: In case of a.c. welding the problem of arc blow not arise whereas in d.c. it occurs. A large current produces arc blow. The space around the and in the adjacent metal is always threaded in magnetic fields which tend to deflect the arc. This is known as “ ARC BLOW”.

7. WELD POOL: When the arc is obtained , intense heat so produced quickly melts the work under the arc forming the pool of molten metal, this is called “WELD POOL”.

8. SOURCE TRANSFORMER: A sourced transformer used in a.c. are welding in a step down the usual supply voltage (200-400 volts) to the normal open circuit welding voltage (50-90 volts).



9. ELECTRODE: Both non consumable and consumable electrodes are used for arc welding. Non consumable electrodes are made of carbon, graphite, tungsten etc. whereas consumable electrodes are made of metal depending upon their purpose.The consumable electrode are classified into bare or on coated and coated electrode. In coated electrode a coating of same fluxing material is provided over the electrode.

10. HELMET: The rays coming out during arc welding for process are harmful so it is advisable to wear helmet.

11. HAND GLOOVES: While welding hand gloves should be worn so that hands are protected from extreme heat evolved out, if it mistakenly strikes the hand.

12. APRON: Before starting the arc welding we need to protect our body, so an apron is worn so as to follow the safety precaution for our safety.



GAS WELDING Gas welding is done by burning a combustible gas with air and oxygen in a concentrated flame of high temperature. Equipment is inexpensive, versatile and serves adequately in many job and general repair shape.

Oxyacetylene gas welding is accomplished by melting the edges as surfaces to be joined by a gas flame and allowing the molten metal to flow together thus forming a solid continuous joint upon cooling. It is suitable for joining metals sheets and plates having thickness from 2 to 50 mm for more thickness additional metal [ called filter metal] from the welding rod is melted in to the gap between the two parts to be joined. The material of welding rod is usually as same as that of the parts being welded. A flux is used during welding to remove impurities and oxides present on the surface of metal to be joined and to obtain a good weld result.

TERMS USED IN GAS WELDING PROCESS

1. OXY ACETYLENE WELDING : When acetylene is mixed with pure Oxygen, it burnt to produce the highest flame temperature about 3200oC, suchFlame is known as “ Oxy Acetylene Flame” The welding done using this flame is called “Oxy Acetylene Welding”.

2. NEUTRAL FLAME : This flame is obtained by supplying equal volumes of Oxygen and acetylene. It has the following two sharply defined zones :

i] An inner luminous cone.ii] An outer cone or envelope of bluish colour. Mostly “ Neutral Flame” is used

for welding.

3. OXIDISING FLAME : This types of flame is obtained where there is an excess of oxygen. It is similar to neutral flame but its inner core is less luminous and shorter. It has the following two zones.

i] The small inner core which has purplish linger.ii] The outer core or envelope.

It is used for welding bars and bronze. It is not used for welding steel as itIncreases the brittleness.



4. REDUCING FLAME : This types of flame is obtained by supplying an excess of acetylene. This flame has following three zones :

i] An inner core which is sharply defined.ii] An intermediate core of whitish colour. iii] An outer core of bluished colour.

The “ Reducing Flame” is also called as “ Carburizing Flame.”

5. LOW PRESS WELDING : In low pressing welding the pressure of acetylenes’ less than 7 KN/M2. This low pressure C2H2 is produced by chemical reaction Between water and calcium carbide. The high pressure oxygen passing through The venture creates a low pressure which draws in low pressure acetylene and Mix with it before both gases pass into the tip.

6. OXYACETYLENE CUTTING : It is used for cutting heavy sectionsIt has a merely suitable length of black iron pipe at one end to which an

oxygen hose is connected. After preheating the welding torch, it is removed and end of lance is brought against the heated area. The oxygen pressure for this operation is 500 – 700 KN/ M2.

7. ACETYLENE GENERATOR: In low pressure welding acetylene is Generated in an acetylene generator where chemical reaction takes place between water and calcium carbide.



TOOLS COMMONLY USED IN OXY ACETYLENE GAS WELDING.

1. WELDING ROD/ FILTER ROD : The welding rods or filter rods are used in gas welding to provide extra metal to the weld by melting the end of the rod. The composition of welding rod material is mostly same as that of the material being welded.

2. WELDING TORCH : The welding torch [also known as blow pipe] is a Tool for making mixing of oxygen and acetylene in desired volumes and burning the mixture at the end of a tip.

3. GAS CYLINDERS : The oxygen and acetylene are usually obtained from strong steel cylinders which are filled by commercial suppliers of this gas. The standard colour of oxygen cylinder is black and of acetylene cylinder is brown.

4. HAND GLOVES : The gloves should be work during welding to protectour hands i.e. to avoid the danger.

5. GOGGLES : The goggles fitted with coloured glosses should be warm by the operator when welding. The goggles protect the eyes from the glare

of the flame cone and molten metal.

6. SPARK LIGHTER : It provided a convenient and instant means for lighting the welding torch.

7. PRESSURE REGULATOR : The function of a pressure regulator is to reduced the cylinder pressure to the required working pressure and also to produce a steady flow of gas regardless of the pressure variations at the source.

-::O::-



AIM :- To prepare in welding job..

TOOLS REQUIRED:-A.C or D.C are machine, electrode holder, cable plug, cable chipping, hammers, wire brush, welding transformers.

PROCEDURE:-i) First we have to cut piece of wild steel of same of equal dimensions.ii) Now locate the centre line of its length of one piece.iii) The slide of wood piece is joined with vertically.iv) Now the compound welded piece is kept in hot water for same time.v) Now extra flux is removed using the chipping hammers.vi) Hence the T-joint is prepared using welding.

PRECAUTIONS:- i) The operator hands, face, eye are to be protected while the arc is in use because the utensils of heat and light rays from the electric arc.ii) Hand grooves should be used.iii) Apron should be used



FITTING SHOP

AIM:- To study tools and operation in fitting shop.

List of various tools used in fitting shop:-

1. Holding and supporting tools a) Bench vice

b) Hand vice c) Pipe vice d) Leg vice

e) Pin vice f) Tool maker vice

2. Marking and measuring tools a) Outside calipersb) Inside calipersc) Odd leg calipersd) Surface platee) Scriberf) Punchg) V blockh) Angle plate i) Tri squarej) Combination set

3. Striking toolsa) Ball peen hammerb) Cross peen hammerc) Straight peen hammerd) Soft hammer

4. Miscellaneous toolsa) Reamerb) Scraperc) Drilld) Tapse) Stocksf) Scriberg) Wheel braceh) Rachet brace

i) Portable electric hand drill

5. Cutting tools a) Chisel b) Flat chiselc) Cross cut chiseld) Half round chisele) Diamond pointed chiself) Side chisel



g) Hacksawh) Filesi) Flat filej) Hand filek) Square filel) Pillar filem) Knife filen) Triangular fileo) Round filep) Half round file

Brief description of tools1.Holding tools:-

Name Description and uses

a) Bench vice It is used for holding work and it is fixed to bench with bolts and nuts. It consist of an iron body, square threaded screw ,nut handle, two jaws and jaw plates. The height of the bench should be such that the top of the vice jaws is it about the same height as the operators elbow.

b) Pipe vice It is used for holding pipes, shafts or round jaws .It works on the same principle as the bench vice. It consist of two jaws one which is fixed and the other is movable .The shape of the jaws is like V and it grips the work at four points on its surface.



2. Marking and measuring tools:-


a) Try square It consists of steel blade fixed at right angles to the edge of machined stock of cast iron. It is used for testing the squareness of surfaces and to set off the lines at right angles to a given edge.

b) Surface plate It is made up of grey cast iron. It is usually square or reactangluare. It is used to check the trueness of flat surfaces and to copy the master surface on a work. A thin coating of red lead mixed with a oil is spread evenly over the surface plate.

c) Scriber It is round hard and steel piece. Its one end is sharp pointed while the other is bent. The bent is used to scratch line a place where the straight end can’t.

d) Combination set It incorporates all the essential features of try square ,protractor, rule and scriber. It has four parts that is square head ,protractor head ,center square head and rule or blade.

e) V - Block It is made up of cast iron. The two opposite faces have v-grooves and the two have slots. It is used for holding round bars during marking. It is also suitable to hold round bars while they are drilled at right angles to their axis.

f) Angle plate It is made up of cast iron. It has two plan surfaces at right angle. The angle plate is used in conjunction with the surface plate for supporting work.



4. Cutting tools:-


a) Files A file is a hardened piece of high grade steel with slanting rows of teeth. It is used to cut, smooth or fit metal parts .It cuts only on forward stoke. It consists of a blade or body with a tang for fixed into the wooden handle. The metal ring on the file handle is called ferrite. The files are classified according to their size, teeth, grade and shape. same types are square file, triangular file, half round file etc..

b)Chisel It is a very important tool used by the fitter. The cutting edge is ground to an angle suited to material being worked upon. The various angle formed on the chisel are cutting angle, clearance angle and rake angle.

c)Scrapper A scrapper is tool with sharp edges by means of which very small amount of metal can be removed. It is used to improve the lack or finish of surfaces. It is made up of tool steel, provided with wooden handle.

4.Micselleneous tools :-

Name Description and usesa)Drills These are used for making round holes

in the work. They are of three types – flat type drills, straight fluted drill and turst drill. The drills are taken out from the machine spindle with the help of a drift.

b)Taps A tap is used for cutting internal threads into a hole. The tap is provided with cutting edges and hardened. It is made up of high carbon steel. The flute at the front of the threads is ground. They are of three types –taper taps, intermediate tap and bottoming tap.



c)Dies The tool is used for cutting external threads on bars or tubes is called a die. It consist of nuts having portion of its threads circumference cut away shaped to provide cutting edges to the remaining portions of the thread.

d)Reamer In order to produce a hole having sufficiently good qualities of finish and accuracy for much purpose, a reamer is used. It imparts the necessary smoothness.

5.Striking tools

Name Description and uses a)Ball peen hammer This hammer has the peen of the shape

of a ball. It is most common types of the hammer and is mostly used for riveting and chipping. The size of a ball peen hammer various from 0.11kg to 0.97kg.

b)Cross peen hammer It is similar to the ball peen hammer accept that its peen is like a wedge which is perpendicular to the handle. It is used for bending ,stretching, hammering into shoulders, inside curves etc..Its size varies from 0.22 kg to 0.97kg.

c)Straight peen hammer This hammer has its peen straight or parallel to the handle. The width of peen is usually equal to the diameter of the face. It is used for stretching or preening the metal by hammering. Its size varies from 0.11kg to 0.97 kg.



Brief description of various fitting operations

a) Drilling:The operation of making holes in metal pieces is known as drilling. It is done with the help of a drilling machine. The most commonly used drilling machine is vertical drilling machine.

B) Reaming:The reaming is a process of importing necessary smoothness, parallelism, roundness and accuracy in size to the previously drilled hole by using a reamer. The hand reaming is mostly done when exactness is required.

c) Chiseling:The operation used for cutting or removing thick layers of metal by means of cold chisels is known as chipping or chiseling.

D) Tapping:The process of cutting internal threads into a drilled hole by using a tap is known as tapping.

e) Dieing:The process of cutting external threads on the round stem of object like bolts, steel and pipes by using die and stock is known as dieing.

f) Punching:The process of marking on a work using punch is known as punching. A punch is made up from 10mm octagonal cast steel about 100mm long.

g) Filing:Filing is required after chipping or cutting operation to remove burn and

clean the feet of cuts and to finish shape of the work piece.



- AIM: TO PREPARE FITTING JOB.-01 & 02

- TOOLS REQUIRED: Different types of files such as half round file, triangular file etc. Tab set, branch vice, try square, scale etc.

- PROCEDURE: 1. Take a place of mild steel block. 2. File it until it has dimensions of 45*45mm. 3. Fitting is done from both the sides. 4. Always clock, the dimension with scale and level with try square. 5. Make it a perfect square. 6. Now drilling is done on the centre of the mild-steel with a drill bride of 10.25mm diameter. 7. After the drilling the rule, it is treated with top set. Tap set u.x.1.5mm is used for threading in hale. 8. After drilling in square from corner cut in equal size of 10mm from two sizes.

PRECAUTIONS: 1. Mild steel looming fitting must be regularly checked with try square & scale. 2. Avoid quick & rest fitting. 3. Dimension should not be changed. However 1mm is allowed.



SMITHY SHOP

Aim- To study smiting and forging.

Procedure - smiting is the act or art of working or forging the metals in order to modify them into desired shape. In this process relatively small sized jobs are heated in an open fire or hearth and subsequently hammered to get the desired shapes. Forging refers to the process of plastically deforming metals or alloys to the specific shape by compressive force exerted by the same external alloy like hammer press, rolls or by an upsetting machine of same bind.

Forging materials- in all plastic deformation processed such as forging, the work piece required calls for various properties like ductility, and it is the property described as the ability to sustain plastic deformation without fracture even in the presence of tensile stresses. If failure occurs by the machine of discile fracture and is included by tensile stress.

Forgebility- The basic Baltic structure of operation is used to change the shape of the raw material and their alloy seems to be a good index to their relative forgebility and work ability. Forgiblity increases with increase in temperature at point up to a phase e.g. frame ferrite into steel appears as if grain growth becomes excessive. Some alloys are relative easy to forge and may be used to make components with very intricate features. But those which are more difficult to forge require different design approach. Forgiblity thus can be defined as “the relative ability of the material to deform without rupture”.

With forging operation- A number of operations are used to change the shape of the raw materials to the finished form. The typical forging operation are-

Upsetting- Upsetting or heading is the process of increasing the thickness of a bar at the expense of its length and brought about by an end pressure. The pressure may be obtained by driving the end of the bar against the other by supporting on the other hitting with the hammer.

a) Fig. shows the effects of heavy hammer blows on a semiformal heated bar.



b) Shows the effect of comparatively light hammer blows. Local upsets may be obtained as shown at (c) & (d) by heating only by the end or the middle of the bar.

Drawing down or sawing- It is the process of increasing the length of a bar at the expense of its width or thickness. In fig A, B & C illustrate this operation. A represents the original stock, B shows the stocks after hammering with a straight pan hammer or with a top fuller and sledge and C shows the finished forging after the flutter has been end.

Setting down- It is localized drawing down or swelling operation as illustrated at D in fig. In other words it may be said that as the process of thinning down or effected by the set hammer or set usually, the work is fullered at the place where the setting down commences. In fig shows the process of setting down both edges of the bar using the top and bottom fuller and F illustrates how the flutter may be used close to a shoulder.

Punching- It is the process of producing holes, generally cylindrical, by using a hot punch over the pitched of the anvil, over a cylindrical die, or over a hole of the correct size in the swage block. These are the stages in punching a hole.

Bending- Bending is an important operation in forging and is one very frequently used. This may be classified as angular or curvilinear. Bending may be done over the edge of the anvil face, over the anvil horn, in special forms such as the swage block edge, or for bar stock, by inserting the end in the pitched hole and bending the bar with e wrench or tang. When metal is bent the layers of the metal inside are shortened and those on the outside are stretched. When this is bent the additional metal will go to make up the corner.

Welding or Shutting- It is perhaps the principle operation perform by the smith. The metal which remains partly over a wide range of temperature in most easily welded and in this respect wrought iron and mild steel have same advantage over the other metals. A protection to the metal is a coating of flux which covers the surface of the metals and by excluding the air which prevents oxidation.



Fluxes which are commonly used in forge welding consist of clean quarts sand, calcinated boron, or a mixture of four parts boron with one part of saturated ammonia.

Cutting- Cutting of is the form of chiseling whereby a long piece of stock is cut into several specified lengths or a forging is separated (cut off) from its stocks. For hat chiseling steel must be heated in a blacksmith’s hearth or furnace to a light cherry red heat, i.e. from 850 to 950 *c . When cutting from chisel the hammer blows are directed on the chisel head which must be slightly rounded. A notch is first made about one half the thickness or diameter of the stock. After the spot where the stock is to be cut off has been notched, the work must be turned through an angle of 180* and chisel is placed exactly opposite the notch.

Fullering- Fullering or spreading the metal along the length of the job is done by working separate section. In this case the axis of the job is positioned perpendicular to the width of the flat die.

Forging process- The process of reducing the metal billet between flat dies or in a closed impression lie to be a part of predetermined size and shape are called “smith forging or impression die forging “ respectively. Depending on the equipments utilized they are further sub-divided as hand forging, hammer forging, press forging, drop hammer forging, mechanical press forging, upset or machine forging. In generally the method of forging may be therefore classified as follows:

1) Smith die forging – Smith forging, also called flat-die and open-die forging, includes the board field of forging work produced between flat faced dies and possibly supplemented by stock-tooling. The final shape of the forging depends largely on the skill of smith or for size and shape. Smith forging, done by hand on an anvil, is employed only to shape a small number of light forgings, chiefly in repair shapes. Heavy forgings weighing up to 25,000 kg as well as medium forgings in small batches are produced exclusively in hammers and presses.



2) Hand forging- The forging is done by hammering the piece of metal, when it is heated to the proper temperature, on an anvil. While hammering, the heated metal is generally held with suitable tongs. Formers are held on the forging by the smith while the other end is struck with a sledge by a helper. The surface of formers has different shapes and they are used to impart these shapes to the forging. One type of former called a fuller, having a well rounded chisel shaped edge is used to draw out the work. Fullers are also made as anvil fitting so that the metal can be drawn out using both top and bottom fuller.

2) Power forging – Large machine parts cannot be forged by hand. Since the comparatively light blow of hand or sledge hammer is unable to produce a great degree of deformation in the metal. This has led to the use of power hammers and presses in forging. Mal machines which work on forging by blow are called “hammers” while there working by pressure are called “presses”.

3) Power hammers- All power hammers employs the same general principle of operation, a fulling weight striking the blow, with the entire energy being absorbed by the work. Where further blows are necessary the striking weight is raised for the succeeding blow. Some hammers employ only a gravity full, the energy delivered on the work being the product of the weight of the hammer head and the distance of the full. The part of the hammer which serves as a rigid support during forging is called the “anvil block”.

4) Impression die forging- More complex shape of great accuracy cannot be formed by open-die forging techniques, commonly known as die forging or drag forging. Impression die forging make use of cavities in specially prepared dies to produce forged shape in quantities, the finished forging being commercial negatives or duplicates of each other. Since the die is not fully closed it should properly be called as an impression die. The term closed for forging is nevertheless, often applied when the term drop fringing is sometime used to denote the fringing conducted up on the hammer; but this distinction has no particular merits.



5) Drap hammer- Three types of drap hammers are used in making drap forging. They are board or gravity hammer, air lift hammer and power drap hammer or what is usually called steam hammer. The working principle in each of these two types is almost similar to that of the forging hammers. The anvil block of a forging hammer is built on a foundation separate from the forging hammers. The anvil block of a forging hammer is built on a foundation separate from the frame while the anvil of a drap forging hammer is attached to the frames to permit accurate alignment of the upper and lower dies.

Capacity of drap hammer- The same factor as explained in forging hammers determines the energy and force delivered by a drop hammer. Direct calculation to determine what capacity is needed is quite complex. An empirical rule of thumbs is that a gravity drop hammer’s rated size in kilograms should be equal to the product of the area of the final die impression and the flash time 20 to 37, depending on the shape and type of material. A double acting steam drap hammer, may be have a rating of 6 of that of a gravity drap hammer but be suitable suited for the same job.

Press forging – Press forging is done in press rather than in hammers. The action is relatively deep because it gives metal time to flow. Dies may have less draft, and the forgings came nearer to the desired sizes. Press forging areshaped at each impression with a single smooth strake and they stick to the die impression more rigidly. Unless some provision are, therefore, made the escape of air and excess die lubricate may be difficult.

High energy rate forging – Although most presses don’t run at high speed, forging is done at high impact rates on some occasions. This is different from hammer forging because the blows are not repeated. A major contribution to the conventional forging operation is their high compact velocity which is 2 to 10 times larger than conventional velocities. In the conventional practices the mass term is made ever larger to obtain heavier forging forces, whereas in high velocity forging the velocity term has been increased. High energy rate forming or forging is sometime called “high velocity forming (HVF)” machines are vertical counter blow machine used principally for hot forging although they



can also be used for cold forming, making powder , metal parts and deep forming sheet metal parts.

Fibrous structure of forging: grain flow – In forging metal flow similar to the flow of sand-cement mortar while being squeezed. Forging causes the grain and randomly dispersed small inclusion and regeneration found in cast metal to get elongated in the same direction as the metal is caused to flow. If a forged part is cut in a plane aligned with direction and surfaces is ground smooth and then immersed in an acid solution the exposed metal will appear to the naked eye to have a fiber-like structure. A section of an upset gear blank after deep etching is shown in fig. These fibers are non metallic inclusions or those phases that are elongated in the directions of the metal or flowed in the direction of working. Grain flow fiber structure, flow lines and forging fibers are terms used to define this effect. The grain flow of forged parts resemble in many ways the grain of wood like wood the strength and the toughness of this metal is greatest in the direction of the fibers. In the directions at the right angle to these fibers, the strength is normally no greater than that found in dense sound castings.



FOUNDRY SHOP

FOUNDRY

Introduction :- Foundry or casting is a process of forming metallic products by melting the metal, pouring it into a cavity known as the mould, and allowing it to solidify" A foundry is a place in workshop where castings are produced

Foundry

Molding Casting Pattern

(a) Green Sand It is classified in detail further (a) Single Piece(b) Dry Sand (b) Split(c) Facing Sand (c) Match plate(d) Backing Sand (d) Cope & Drag(e) Parting Sand (e) Gated(f) System Sand (f) Loose Piece(g) Core Sand (g) Sweep(h) Loam Sand (h) Segmental

(i) Skeleton(j) Shell(k) Built up(l) Boxed up(m) Lagged up(n) Left & Right

Firsuy introduced molding

Molding

Introduction :- A mould may be defined as the impression of pattern in the molding sand In foundry when pattern is ready, it is been placed on board and using molding box, its impression is taken by filling and ramming molding sand. The area used for making mould is known as molding section.

" Molding is a process of making cavity or mould with the help of sand by means of pattern ''

Classification of Molding sand



(a) Green Sand :- it is mixture of silica sand with 18 to 30 % clay having a total water of from 6 to 8 % Moulds prepared in this sand are known as green sand moulds. it is fine, soft, light and porous.

(b) Dry Sand :- Green sand that has been dried or baked after the mould is made is called dry sand. They are suitable for larger castings. Moulds prepared in this sand are know as dry sand molding.

(c) Loam sand :- Loam sand is high clay as much as 50 % or so, and dries hard. This is particularly employed for loam molding usually for large casting.

(d) Facing Sand:- Facing Sand forms the face of mould. It is used directly next to the surface of the pattern it comes into tact with the molten metal when the mould is poured.

(e) Baking Sand :- Backing Sand is sometimes called black sand because of the fact that old. repeatedly used molding sand is black in colour due to the addition of coal dust and bumming on coming in contact with molten metal.

(f) System Sand :- In mechanical foundries where machine molding is employed a so called system sand is used to fill the whole flask.

(g) Parting Sand :- Parting sand is used to keep the green sand from sticking to the pattern and also to allow the sand on the parting surface of the cope and drag to separate without clinging

(h) Core Sand :- Sand used for marking cores is called core sand, sometimes called oil sand Pitch or flours and water may be used in large cores for the scale of economy

Properties of Molding sand

Molding

Porosity, Collapsibility, Refractoriness, Flowabillity, Adhesiveness, Cohesiveness or Strength,

Proper molding sand must possess six properties, It must have porosity flowabillity collapsibility, adhesiveness, cohesiveness and refractoriness.

(a) Porosity:- Porosity or penneabillity is the ability of dand to allow air, steam and hot gases to escape from the mould during pouring of molten metal. It depends upon size & shape of grain, moisture and clay content and ramming conditions.



(b) Flowabillity:- Flowabillity of molding sand refers to its ability to behave like a fluid so that when rammed, it will flow to all portion of a mould and pack all round the pattern and take up the required shape. Flowabillity increases as clay and water content increases.

(c) Collapsibility :- After the molten metal in the mould gets solidified, the sand mould must be collapsible so that free contraction of metal during cooling takes place.

(d) Adhesiveness:- This property that the sand mass can be successfully held in a molding box and it does not fall out of the box when it is removed.

(e) Cohesiveness & Strength:- This is the ability of particles to stick together. The mould may also be damaged during pouring by washing of the walls and core by the molten metal.Strength is of two types :- (1) Green Strength, (2) Dry Strength

(1) Green Strength :- The property of sand in its green or moist state is know as green strength.

(2) Dry Strength :- The Strength of sand that had been dried or baked is called dry strength.

(f) Refractoriness :- Refractoriness is property of sand to withstand high temp it depends upon silica or quartz content. The sand having high silica content is considered Bette.

Casting

Casting is a process of pouring molten metal or cavity and allowing it to solidify

Basic steps for casting :-



Casting

Pattern & core Melting & PouringCleaning & Inspectionbox makingCastingMould & Core making

1. Pattern & Core box making : Pattern may be defined as a model or replica of casting. Patterns are designed & fabricated with provision for molding, coring and machining and are used to form an impression in damp sand. For the casting having pockets, patterns are modified with core point so as to have space for placement of core. Hence prior to molding it is necessary to have a pattern and core box, depending upon the type of casting.

2. Mould & Core making : Patterns are used to form impression in the damp sand known as mould. For cavities and pockets cores are placed in the mould. The cores are made by molding core sand in core box with proper reinforcement and then baking in a oven.

3. Melting & Pouring : When moulds are ready, the melt is prepared by heating metal to cast in a suitable furnace. The molten metal is then poured in the mould. The moulds are then allowed to cool so that metal in mould gets solidly.

4. Cleaning of Casting : When the process of solidification is complete, the castings are taken out by breaking moulds. The attachments to the castings are then cut and sand adhering to the surface is cleaned. The castings are then offered for inspection.

5. Inspection of Casting : The castings are susceptible for many defects are inspected prior to use or machining.



PATTERN

Pattern is the principle tool during the casting process. It may be defined as a model of anything, so constructed that it may be used for forming an impression called mould in damp sand or other suitable material. When this mould is filled with molten metal, and the metals allowed to solidify, it forms a reproduction of the pattern is known as casting. The process of making a pattern is known as pattern making.

Type of Patterns :

1. Single Piece or solid pattern : A pattern that is made without joints, partings or any loose pieces in its construction is called a single piece or solid pattern. A single piece pattern is not attached to a frame or plate and is therefore, sometimes known as loose pattern. These pattern are cheaper.

2. Split pattern : Many patterns can't be made in a single piece because of the difficulties encountered in molding them. To eliminate this difficulty, and for castings of intricate design or unusual shape. This pattern usually made in two parts, sometimes is called multi-piece or split pattern.

3. Match Plate pattern : In match plate pattern one half of split pattern is mounted on one side of a plate and other half directly opposite on other side of plate. One or more number of pattern can be mounted on a plate with gates and runner on drag side. Match plate act as parting line which can be of wood or metal. Patterns are made from metals.

4. Cope & drag pattern : In the case of large size casting the cope and drag part of mould are made independently. A plate is been used to avoid difficulty in alignment of cope and drag.

5. Gated Pattern : These patterns are designed for producing multi-cavity moulds. A group of patterns with attached gate former is known as gated pattern.

6. Loose piece pattern : Loose piece pattern are required when pattern can't be removed in one piece. The main pattern is removed first then other pieces are removed by creating space to withdraw them. The part lines is fixed on more than one plane.

7. Sweep Pattern : For large symmetrical castings, moulds are made by rotating a sweep board having shape corresponding to the shape of casting. Sweep eliminates the expensive pattern.

8. Skeleton pattern : To cut down cost of pattern, some times skeleton is made using cut size timber. The frame is then filled with sand having clay or loam. The cope and drag made separately.

9. Segmental pattern : For a large ribbed casting, a segment is used for making mould. This type of pattern is known as segmental pattern. It is used for making mould of large casting.



PATTERN ALLOWANCES

Shrinkage Machining Rapping Distortion DraftAllowance Allowance Allowance Allowance Allowance

1. Shrinkage Allowance : Almost all the metals used in castings contract or shrink after solidification in mould. Therefore, the pattern must have some additional dimension to get accuracy. The allowance provide d for this is known is shrinkage allowance.

2. Draft Allowance : Draft allowance is given to all the vertical walls or parts of the pattern for easy and safe withdrawal of pattern from the molding sand without damaging the molding cavity.

3. Machining Allowance : The product obtained from casting is required to be machined. So pattern is given some additional size, that allowance is known as machining allowance.

4. Distortion Allowance : This allowance is provided on the pattern for casting of such complicated design in which the contraction is not uniform throughout. In order to compensate this distortion allowance is provided in the opposite direction of pattern.

5. Rapping Allowance : Rapping allowance is provided in the pattern in order to compensate for the rapping of mould because the pattern is to be rapped before removing from the molding sand.



MOULDING MATERIAL

Molding Tools and Equipments:

Shovel : it is used for missing and temperature molding sand.

Riddle : A riddle is consist of a circular or square wooden frame fitted with a standard wire mesh at the bottom.

Rammer : A hand rammer is a wooden tool used for packing or ramming the sand into the mould.

Trowel : A trowel consist of a metal blade fitted with a wooden handle. The usual trowel is rectangular in shape and has either a round or square end.

Slick : It is a small double ended tool having a flat on one end and a spoon on the other end. The type most commonly used is the oval spoon.

Strike Off bar : The strike off bar is a piece of metal or wood with a straight edge. It is used to stickle sand from the mould after ramming to provide a level surface.

Gate cutter : It is a small piece of tin plate shaped. The serves as a tool for cutting gates and runners in the mould.

Mallet : A raw hide mallet is used to loosen the pattern in the mould so that it can be withdrawn without damages to the mould.



Foundry tools & equipments

Hand Tools Flasks Mechanical Tools

2) Artificial Seasoning :

(i) Mc Nails seasoning(ii) Hot air seasoning(iii) Seasoning by boiler in water(iv) Seasoning by Steaming

Following are some of the points considered for selection of timber :

(i) Work : For superior quality work like furniture and interior common wood in use are jeak, rose and mahogany.

(ii) Appearance : It should have hard and shining appearance.

(iii) Color : The color of timber should always dark. The timbering having light color indicates low strength timber.

(iv) Defect : It should be free from defects such as flows shakes, knots etc.

(v) Durability : It should be durable enough to capable of resisting the action of fungi, insects, chemicals, physical agencies and mechanical agencies.

(vi) Finish : excellent finish can be obtained with jeak, rose, mahogany.

(vii) Stability : stability in shape, should not in wrap.

(viii) Cost: cost should be low.

Non Precision Instruments: Which can measure dimension to a visible line graduation on the instrument? E.g. Steel scale / rule.

Line Measuring: by placing instrument along the line of graduation. E.g. Steel scale/ rule.

End measuring: in an end measuring device the measurement is taken between two ends. E.g. Venire calipers, micrometers etc.



Type of Instruments

Direct reading : a direct measuring instrument gives absolute value of the actual dimensions. E.g. micrometers, venire calipers, steel scale etc.

Transfer type : in a indirect measuring instrument, the measurement from the work piece is transferred to direct measuring instrument. E.g. divider caliper etc.

Type of dimensions

Linear measuring instruments : to measure length, width, thickness & diameter. E.g. micrometer, venire calipers, steel scale etc.

Angular measuring instruments : to measure angles, E.g. bevel protector combination set.

Surface measuring instrument : to measure & the surface accuracies. E.g. straight edge, dial indicator.

Linear measurements

Steel rule : Amongst the line measuring instruments, the steel rule/scale is one of the most, useful tool in the shop for taking linear measurements i.e. length, width and height. It consists of strips of hardened steel having line graduation etched or engraved, at interval, of fraction of a standard unit, of length.


workshop manual 2011 2012

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