engineering workshop

7/23/2019 Engineering Workshop

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ENGINEERING

WORKSHOP

LAB MANUAL



Engineering Work Shop Department of MechanicalEngineering



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CONTENTS

Instructions for Laboratory ……….4

S.No. Experiment Page no.

1. BLACKSMITHY 6

2. CARPENTRY 1

3. !ITTIN" ##

4. !O$N%RY 1

5. TINSMITHY &#

6. 'EL%IN" ()

7. HO$SE'IRIN" 61

8. P$MBLIN" 6*

9. PO'ER TOOLS +&

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In,tr-tion, /or La0orator

• The objective of the laboratory is learning. The experients are !esigne! to ill"strate phenoena in !ifferent

areas of #or$shop an! to expose yo" to "ses of instr"ents. %on!"ct the job &ith interest an! an attit"!e of

learning.

• 'o" nee! to coe &ell prepare! for the job.

• #or$ ("ietly an! caref"lly )the &hole p"rpose of experientation is to a$e reliable eas"reents*+ an!

e("ally share the &or$ &ith yo"r partners.

• ,ll presentations of job an! !iagra sho"l! be neatly an! caref"lly !one.

• -iagras sho"l! be neatly !ra&n &ith pencil. ,l&ays !isplay "nits.

•

%oe e("ippe! &ith scales pencils etc.

• -o not fi!!le i!ly &ith apparat"s. /an!le instr"ents &ith care. 0eport any brea$age to the nstr"ctor. 0et"rn

all the e("ipent yo" have signe! o"t for the p"rpose of yo"r experient.



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yllab"s

B. 2. RA3$ INSTIT$TE O! TECHNOLO"Y 4A$TONOMO$S5 NARSAP$R ME%AK 4%IST5

I Year B. Te7 L T8P8% C

9 9 8 8 9 #

EN"INEERIN" 'ORKSHOP

4Common to a:: 0ran7e,5

O0;eti<e

To failiarise &ith the basic an"fact"ring processes an! to st"!y the vario"s tools an! e("ipent "se!han!son training is given in !ifferent sections. ssentially st"!ent sho"l! $no& the labo"r involve!achinery or e("ipent necessary tie re("ire! to fabricate an! also sho"l! be able to estiate the costof the pro!"ct or job &or$.

TRA%ES !OR E=ERCISES>

,t least t&o exercises fro each tra!e

a. %arpentry i!!le lap T joint cross lap joint ortise an! tenon T joint ri!le T joint b. itting ("are joint joint half ro"n! joint !ovetail joint

c. Tinithy Tray cylin!er hopper f"nnel

!. lac$ ithy iple exercises base! on blac$ sithy operations s"ch as "psetting !ra&ing !o&n p"nching ben!ing s&aging an! f"llering

e. /o"se&iring &iring for ceiling rose an! t&o laps )b"lbs+ &ith in!epen!ent s&itch controls &ith or &itho"t looping &iring for stair case lap &iring for a &ater p"p &ith single phase starter.

f. o"n!ry single pattern !o"ble pattern

TRA%ES !OR %EMONSTRATION>

a. :l"bing b. achine hop

c. #el!ing!. :o&er tools in constr"ction &oo! &or$ing electrical engineering an! echanical ngineering.

;"tcoes

asic practice sessions "st be con!"cte! in the tra!es entione! an! then t&o pro!"cts of n!"strialapplication )&ith cobination of !ifferent tra!es+ ay be pro!"ce! &ith the available reso"rces.

RE!ERENCE BOOKS>

1. ngineering #or$ shop practice for <=T> . 0aesh ab" 0 :"blishers :vt. ?t!.

2. #or$ shop an"al @ :.Aannaiah@ A.?.=arayana@ ciTech :"blishers.

3. ngineering :ractices ?ab an"al <eyapoovan aravana:an!ian i$as p"blishers

4. -ictionary of echanical ngineering B/ =ayler <aico :"blishing /o"se.

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BLACKSMITHY

lac$sithy or orging is an ol!est shaping process "se!

for the pro!"cing sall articles for &hich acc"racy in siCe is

not so iportant. The parts are shape! by heating the in an

open fire or hearth by the blac$sith an! shaping thethro"gh applying copressive forces "sing haer.

Th"s forging is !efine! as the plastic !eforation of etals at elevate! teperat"res into a

pre!eterine! siCe or shape "sing copressive forces exerte! thro"gh soe eans of han! haers

sall po&er haers !ie press or "psetting achine. t consists essentially of changing or altering the

shape an! section of etal by haering at a teperat"re of abo"t 98DE% at &hich the etal is entirely

plastic an! can be easily !efore! or shape! "n!er press"re. The shop in &hich the vario"s forging

operations are carrie! o"t is $no&n as the sithy or sithFs shop.

/an! forging process is also $no&n as blac$sithy &or$ &hich is coonly eploye! for

pro!"ction of sall articles "sing haers on heate! jobs. t is a an"al controlle! process even tho"gh

soe achinery s"ch as po&er haers can also be soeties "se!. lac$sithy is therefore a

process by &hich etal ay be heate! an! shape! to its re("ireents by the "se of blac$sith tools either by han! or po&er haer.

orging by achine involves the "se of forging !ies an! is generally eploye! for ass

pro!"ction of acc"rate articles. n !rop forging close! ipression !ies are "se! an! there is !rastic flo&

of etal in the !ies !"e to repeate! blo& or ipact &hich copels the plastic etal to confor to the

shape of the !ies.

App:iation, o/ /orging

,lost all etals an! alloys can be forge!. The lo& an! e!i" carbon steels are rea!ily hot forge!

&itho"t !iffic"lty b"t the highcarbon an! alloy steels are ore !iffic"lt to forge an! re("ire greater care.

orging is generally carrie! o"t on carbon alloy steels &ro"ght iron copperbase alloys al"in" alloys

an! agnesi" alloys. tainless steels nic$elbase! s"per alloys an! titani" are forge! especially for

aerospace "ses.!OR"EABILITY

The ease &ith &hich forging is !one is calle! forgeability. The forgeability of a aterial can also be

!efine! as the capacity of a aterial to "n!ergo !eforation "n!er copression &itho"t r"pt"re.

orgeability increases &ith teperat"re "p to a point at &hich a secon! phase e.g. fro ferrite to

a"stenite in steel appears or if grain gro&th becoes excessive.

COMMON HAN% !OR"IN" TOOLS

or carrying o"t forging operations an"ally certain

coon han! forging tools are eploye!. These are

also calle! blac$sithFs tools for a blac$sith is one

&ho &or$s on the forging of etals in their hot state.

The ain han! forging tools are as "n!er.Tong,

The tongs are generally "se! for hol!ing &or$ &hile!oing a forging operation. ario"s $in!s of tongs aresho&n in ig"re.

a+ traightlip fl"te! tongs are coonly "se! for hol!ing s("are circ"lar an! hexagonal bar stoc$.

b+ 0ivet or ring tongs are &i!ely "se! for hol!ing bolts rivets an! other &or$ of circ"lar section.

c+ lat tongs are "se! for ainly for hol!ing &or$ of rectang"lar section.

!+ Ba! tongs are "se! for hol!ing general pic$"p &or$ either straight or tapere!.

!:atterlatter is sho&n in ig. 14.7. t is coonly "se! in forging shop to give soothness an! acc"racy toarticles &hich have alrea!y been shape! by f"llers an! s&ages.

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S?age

&age is "se! for forging &or$ &hich has to be re!"ce! or finishe! to ro"n! s("are or hexagonal for. t

is a!e &ith half grooves of !iensions to s"it the &or$ being re!"ce!. t consists of t&o parts the top

part having a han!le an! the botto part having a s("are shan$ &hich fits in the har!ie hole on the anvil

face.

!-::er"ller is "se! in forging shop for nec$ing !o&n a forgeable job. t is a!e in top an!

botto tools as in the case of s&ages. "ller is a!e in vario"s shapes an! siCesaccor!ing to nee!s the siCe !enoting the &i!th of the f"ller e!ge

P-n7

:"nch is "se! in forging shop for a$ing holes in etal part &hen it is at forging heat.

Ri<et 7ea@er

0ivet hea!er )ig. 14.7+ is "se! in forging shop for pro!"cing rivets hea!s on parts.

C7i,e:,

%hisels are "se! for c"tting etals an! for nic$ing prior to brea$ing. They ay be hot or col! !epen!ingon &hether the etal to be c"t is hot or col!. , hot chisel generally "se! in

forging shop is sho&n in ig. 14.7. The ain !ifference bet&een the t&o is in

the e!ge. The e!ge of a col! chisel is har!ene! an! tepere! &ith an angle of

abo"t 6DE &hilst the e!ge of a hot chisel is 3DE an! the har!ening is notnecessary. The e!ge is a!e slightly ro"n!e! for better c"tting action.

Han@ 7ammer,

There are t&o ajor $in!s of haers are "se! in han! forging

a. The han! haer "se! by the sith hiself an!

b. The sle!ge haer "se! by the stri$er.

/an! haers ay f"rther be classifie! as )a+ ball peen haer )b+straight peen haer an! )c+ cross peen haer.

le!ge haers ay f"rther be classifie! as )a+ -o"ble face haer

)b+ straight peen haer an! )c+ cross peen haer./aer hea!s are a!e of cast steel an! their en!s are har!ene! an! tepere!. The stri$ing face is a!eslightly convex. The &eight of a han! haer varies fro abo"t D.5 to 2 $g &hereas the &eight of asle!ge haer varies fro 4 to 1D $g

Set 7ammer

, set haer generally "se! in forging shop is sho&n in ig. 14.9. t is "se! for finishing corners insho"l!ere! &or$ &here the flatter &o"l! be inconvenient. t is also "se! for !ra&ing o"t the gorging job.

An<i:

,n anvil is a ost

coonly tool "se! inforging shop &hich is

sho&n in. t acts as a




s"pport for blac$sithFs &or$ !"ring haering. The bo!y of the anvil is a!e of il! steel &ith a tool

steel face &el!e! on the bo!y b"t the bea$ or horn "se! for ben!ing c"rves is not steel face!. The ro"n!

hole in the anvil calle! pritchel hole is generally "se! for ben!ing ro!s of sall !iaeter an! as a !ie for

hot p"nching operations. The s("are or har!ie hole is "se! for hol!ing s("are shan$s of vario"s fittings.

,nvils in forging shop ay vary "p to abo"t 1DD to 15D $g an! they sho"l! al&ays stan! &ith the top face

abo"t D.75 t. fro the floor. This height ay be attaine! by resting the anvil on a &oo!en or cast iron base in the forging shop.

S?age 0:o

&age bloc$ generally "se! in forging shop is sho&n in fig"re. t is ainly "se! for hea!ing ben!ings("aring siCing an! foring operations on forging jobs. t is D.25 t. or even ore &i!e. t ay be "se!either flat or e!ge&ise in its stan!.

!OR"IN" OPERATIONS>

The follo&ing are the basic operations that ay be perfore! by han! forging

1. %ra?ing9@o?n>-ra&ing is the process of stretching the stoc$ &hile re!"cing its crosssection locally. orging the

tapere! en! of a col! is an exaple of !ra&ing operation.

#. $p,etting>

t is a process of increasing the area of crosssection of a etal piece locally &ith a correspon!ing

re!"ction in length. n this only the portion to be "pset is heate! to forging teperat"re an! the &or$ is then

str"c$ at the en! &ith a haer. /aering is !one by the sith )st"!ent+ hiself if the job is sall or by

his helper in case of big jobs &hen heavy blo&s are re("ire! &ith a sle!ge haer.

. !-::ering>

"llers are "se! for nec$ing !o&n a piece of &or$ the re!"ction often serving as the starting point for !ra&ing. "llers are a!e of high carbon steel in t&o parts calle! the top an! botto f"llers.

The botto tool fits in the har!ie hole of the anvil. "ller siCe !enotes the &i!th of the f"ller e!ge.&. !:attering>

latters are the tools that are a!e &ith a perfectly flat face of abo"t 7.5 c s("are. These are"se! for finishing flat s"rfaces. , flatter of sall siCe is $no&n as sethaer an! is "se! for finishingnear corners an! in confine! spaces.

(. S?aging>

&ages li$e f"llers are also a!e of high carbon steel an! are a!e in t&o parts calle! the top an!s&ages. These are "se! to re!"ce an! finish to ro"n! s("are or hexagonal fors. or this the s&ages area!e &ith half grooves of !iensions to s"it the &or$.

6. Ben@ing>

en!ing of bars flats etc. is !one to pro!"ce !ifferent types of bent shapes s"ch as angles ovals

circles etc. harp ben!s as &ell as ro"n! ben!s ay be a!e on the anvil by choosing the appropriate place on it for the p"rpose.

+. T?i,ting>

t is also one for of ben!ing. oeties it is !one to increase the rigi!ity of the &or$ piece.all piece ay be t&iste! by heating an! claping a pair of tongs on each en! of the section to bet&iste! an! applying a t"rning oent.

?arger pieces ay be clape! in a leg vice an! t&iste! &ith a pair of tongs or a on$ey &rench./o&ever for "nifor t&ist it "st be note! that the coplete t&isting operation "st be perfore! inone heating.

. C-tting 4Hot an@ Co:@ C7i,e:,5>

%hisels are "se! to c"t etals either in hot or col! state. The col! chisel is siilar to fitterFs

chisel except that it is longer an! has a han!le. , hot chisel is "se! for c"tting hot etal an! its c"ttinge!ge is long an! slen!er &hen copare! to col! chisel. These chisels are a!e of tool steel har!ene! an!

tepere!.

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*. Iron9Car0on A::o>

f the carbon is less than 2G in the ironcarbon alloy it is $no&n as steel. ,gain base! on thecarbon content it is calle! il! steel e!i" carbon steel an! high carbon steel. The heat treatent to begiven to these steels an! their applications are sho&n in table belo&.

Car0on Har@ening Tempering App:iation,.

temp. )C temp. )C

D.1 8DD84D 25D3DD %hains rivets soft &ire sheet

Mi:@ Stee:D.25 8DD84D 25D3DD T"be ro! strip

D.5 8DD84D 25D3DD Bir!ers

D.6 8DD84D 25D3DD a&s haers sithFs an! general

p"rpose tools

D.75 76D8DD 25D3DD%ol! chisels sithFs tools shear bla!es

table c"tlery

[email protected] 76D8DD 25D3DD Taps !ies p"nches hot shearing bla!es

-rills reaers c"tters blan$ing an!Car0on ,tee: 1.D 76D8DD 25D3DD slotting tools large t"rning tool

all c"tters lathe an! engraving tools

1.2 72D76D 25D3DD files !rills

Hig7 Car0on 1.35 72D76D 25D3DDxtra har! planning t"rning an! slotting

tools !ies an! an!rels

1.5 72D76D 25D3DD 0aCor bla!es

NOTE> The forging pro!"ce! either by han! forging or achine forging sho"l! be heat treate!.

The follo&ing are the p"rposes of heat treatent

i. To reove internal stresses set"p !"ring forging an! cooling.ii. To noraliCe the internal str"ct"re of the etal.

iii. To iprove achinability.

iv. To iprove echanical properties strength an! har!ness.

SA!E PRACTICES>

1. /ol! the hot &or$ !o&n&ar!s close to the gro"n! &hile transferring fro the hearth to anvil toiniiCe !anger of b"rnsH res"lting fro acci!ental collisions &ith others.

2. >se correct siCe an! type of tongs to fit the &or$. These sho"l! hol! the &or$ sec"rely to preventits bo"ncing o"t of control fro repeate! haer blo&s.

3. %are sho"l! be exercise! in the "se of the haer. The ini" force only sho"l! be "se! an!the flat face sho"l! stri$e s("arely on the &or$H as the e!ge of the haer &ill pro!"ce heavy

br"ising on hot etal.4. #ater face shiel! &hen haering hot etal.

5. #ear gloves &hen han!ling hot etal.

6. #ear steeltoe! shoes.7. ns"re that haers are fitte! &ith tight an! &e!ge! han!les.

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E=P> 1 S9Hoo %ate

Aim> To a$e an hoo$ fro a given ro"n! ro! by follo&ing han! forging operation.

Too:, reD-ire@>

ithFs forge ,nvil 5DDg an! $g ballpeen haers latters &age bloc$ /alf ro"n! tongs :ic$"p tongs %ol! chisel.

SeD-ene o/ operation,>

1. ;ne en! of the bar is heate! to re! hot con!ition in the sithFsforge for the re("ire! length.

2. >sing the pic$"p tongsH the ro! is ta$en fro the forge an!hol!ing it &ith the half ro"n! tongs the heate! en! is forge! intoa tapere! pointe! en!.

3. The length of the ro! re("ires for hoo$ is estiate! an! theexcess portion is c"toff "sing a col! chisel.

4. ;ne half of the ro! to&ar!s the pointe! en! is heate! in the forge

to re! hot con!ition an! then bent into circ"lar shape as sho&n.5. The other en! of the ro! is then heate! an! forge! into a tapere!

pointe! en!.6. The straight portion of the ro! is finally heate! an! bent into

circ"lar shape as re("ire!.

7. >sing the flatter the hoo$ a!e as above is $ept on the anvilan! flattene! so that the shape of the hoo$ is proper.

NOTE> nbet&een the above stage the bar is heate! in the sithFs forge to facilitate forging operations.

Re,-:t>

The hoo$ is th"s a!e fro the given ro"n! ro!H by follo&ing the stages entione! above.

Prea-tion,>1. /ol! the job caref"lly &hile heating an! haering

2. <ob "st be hel! parallel to the face of the anvil.

3. #ear steeltoe! shoes.

4. #ear face shiel! &hen haering the hot etal

5. >se correct siCe an! type of tongs to fit the &or$.

S- HOOK



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E=P> # SD-are Ro@ %ate

Aim> To a$e a ("are ro! fro a given ro"n! ro! by follo&ing han! forging operation.

Too:, reD-ire@>

ithFs forge ,nvil 5DDg an! $g ballpeen haers latters &age bloc$ /alf ro"n! tongs :ic$"p tongs %ol! chisel.


1. Ta$e the ra& aterial fro stoc$ i.e.il! steel 1D ro"n! shape! c"t thelength of 5D .

2. /an!le specien &ith ro"n! tong an!

heat in blac$sithFs forge "pto the partappears as re! cherry color co!e.

3. The re("ire! piece heate! "pto it gets therecrystaliCation teperat"re.

4. The part is ta$en o"t fro the forge an! blo& &ith sle!ge haer for obtainingthe s("are shape on all e!ges.

5. The haering is !one on the anvil.

6. The above entione! all steps are !oneafter the specien bent in re("ire! shape.

7. %hec$ the !iensions after cooling the job by ("enching process.

NOTE> nbet&een the above stage the bar is heate! in the sithFs forge to facilitate forging operations.

Re,-:t>

The s("are ro! is th"s a!e fro the given ro"n! ro!.

Prea-tion,>

1. /ol! the job caref"lly &hile heating an! haering

2. <ob "st be hel! parallel to the face of the anvil.

3. #ear steeltoe! shoes.

4. #ear face shiel! &hen haering the hot etal

5. >se correct siCe an! type of tongs to fit the &or$.

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CARPENTRY

%arpentry is the process of shaping Tiber "sing han! tools. The pro!"cts pro!"ce! are "se! in

b"il!ing constr"ction s"ch as !oors an! &in!o&s f"rnit"re an"fact"ring patterns for o"l!ing in

fo"n!ries etc. %arpentry &or$ ainly involves the joining together of &oo!en pieces an! finishing the

s"rfaces after shaping the. /ence the ter joining is also "se! coonly for carpentry. , st"!ent

st"!ying the f"n!aentals of &oo! &or$ing has to $no& abo"t tiber an! other carpentry aterials&oo! &or$ing tools carpentry operations an! the etho! of a$ing coon types of joints.

Materia:, $,e@ in Carpentr>

asic aterials "se! in carpentry shop are tiber an! ply&oo!. ,"xiliary aterials "se! are nails scre&sa!hesives paints varnishes etc.

Tim0er>

Tiber is the nae given to &oo! obtaine! fro exogeno"s )o"t&ar! gro&ing+ trees. n these trees the

gro&th is o"t&ar! fro the centre by a!!ing alost concentric layers of fresh &oo! every year $no&n as

ann"al rings. ,fter the f"ll gro&th these trees are c"t an! sa&e! to convert into rectang"lar sections of

vario"s siCes for engineering p"rposes.

Tiber is available in ar$et in vario"s shapes an! siCe. The coon shapes an! siCes an given belo&

1. Log> This is the tr"n$ of !ie tree &hich is tree fro branches. 2. Ba:> This is the log after sa&ing ro"ghly to s("are cross section.

3. %ea:> This is the log after sa&ing into rectang"lar cross section of &i!th abo"t 225 an! thic$ness "p to 1DD .

4. P:an> This is the tiber piece having &i!th ore than 275 an! thic$ness 5D lo 15D .

5. Boar@> This is the tiber piece belo& 5D in thic$ness an! above 125 in &i!th

6. Batten> This is the tiber piece belo& 175 in &i!th an! thic$ness bet&een 3D to 5D in thic$ness.

7. Sant:ing,> These are tiber pieces of vario"s assorte! an! nonstan!ar! siCesother than thetypes given above.

C:a,,i/iation o/ 'oo@The tiber "se! for coercial p"rposes can he !ivi!e! into t&o classes as soft &oo! an! har! &oo!

So/t ?oo@

, soft &oo! is light in &eight an! light colore!. They ay

have !istinct ann"al rings b"t the e!"llar rays )ra!ial

lines+ are not visible an! the color of the sap wood )o"ter

layers+ is not !istinctive fro the heart &oo! )inner layers+.

These &oo!s cannot resist stresses !evelope! across their

fibersH hence not s"itable for &oo! &or$ing.

Har@ ?oo@

n this type of &oo! the ann"al rings are copact an! thin an!

the e!"llar rays )ra!ial linesI are isible in ost cases ig"re6.1. /ar! &oo!s are nearly e("ally strong both along an! across the fibers. /an! &oo! is the aterial "se! for &oo! &or$ing

C:a,,i/iation o/ tim0er

,ccor!ing to the anner of gro&th of trees tiber can be classifie! asi) xogeno"s or o"t &ar! gro&ing

ii) n!ogeno"s or in &ar! gro&ingi5 Exogeno-, or o-t ?ar@ gro?ing

n exogeno"s trees the gro&th ta$e place fro the centre by the a!!ition of concentric layersof fresh &oo! every year $no&n as ann"al rings. These varieties of trees are s"itable for b"il!ing an!other engineering "ses the exogeno"s trees are again classifie! as

a+ %onifers or ever green trees

b+ -eci!"o"s or broa! leaf trees

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The conifer give soft &oo!s an! the !eci!"o"s gives har! &oo! coon exaple of har! &oo! areal tea$ rose &oo! san!al shisha oa$ beach ash ebony ango nee babool etc. soft &oo!incl"!e $ail pine !eo!ar chair &aln"t seeal etc.

ii5 En@ogeno-, or in ?ar@ gro?ing tim0er

These trees gro& in &ar!s i.e. .every fresh layer of sap &oo! is a!!e! insi!e instea! of o"tsi!e cane baboo cocon"tSea,oning

easoning of &oo! carrie! o"t for reoving the sap an! re!"cing the oist"re content the presenceof sap an! oist"re &ill ren!er the &oo! "ns"itable for engineering &or$s !"e to "neven shrin$agecrac$ &rapping an! !ecay.

%i//erent met7o@, o/ ,ea,oning

1. ,ir seasoning or =at"ral seasoning2. #ater seasoning

3. lectrical seasoning

4. Ailn seasoning

P: ?oo@

Thic$ sheet fore! by pasting veneers of &oo! is calle! ply. Three or ore plys joine! by gl"es iscalle! ply&oo!. The grains of a!jacent layers are $ept at right angle to each other in or!er to get betterstrengthening both !irections the o"ter layer are calle! facing plys an! goo! har! &oo! veneers are "se!for this inner ones are calle! core plys an! lo& ("ality &oo! is "se! for this the ply &oo! is a!e byeither col! pressing or hot pressing.

Too:, /or ?oo@ ?oring

The principle han! tools "se! in a carpentry &or$shop can be classifie! into

i) ar$ing an! eas"ring tool

ii) %"tting tooliii) :lanning tooliv) oring toolv) tri$ing tool

vi) /ol!ing toolMaring an@ mea,-ring too:a5 R-:e,

0"les are "se! for eas"ring !iensions. or eas"ring an! setting o"t!iensions vario"s types of r"les are "se! in carpentry shop. teel 0"letainless teel 0"le of length 3Dc an! 6Dc. lexible eas"ring 0"lefor eas"ring large !iensions as &ell as c"rve! or ang"lar s"rface!iensions.

05 Straig7t E@ge an@ SD-are,

This is a achine! flat piece &oo! or etal having perfectly straight an! parallel e!ges.

5 Stee: Tape> t is "se! for large !iensions s"ch as ar$ing on boar!s an! chec$ing the overall !iensions of the &or$.

e5 "a-ge,

Ba"ges are "se! to ar$ lines parallel to the e!ges of a &oo!en piece. t ainly consists of a &oo!enste sli!ing insi!e a &oo!en stoc$. The ste carries a steel point for ar$ing lines. The stoc$

position on the ste can be varie! an! fixe! rigi!ly by tightening the th"b scre&.

Fig. Marking GaugePage 14




To ar$ a line parallel to an e!ge the ga"ge stoc$ is hel! freely against the e!ge an! p"she! along it pressing the steel points to the s"rface

Fig. Mori!e Gauge

5 Tr ,D-are

Try s("are consists of rectang"lar steel bla!e fixe! rigi!ly to cast iron stoc$. The length of bla!evaries fro 15D to 3DD.

Maring Kni/e or Sri0er

ar$ing Anives are "se! to convert the pencil lines !ra&n on the &oo!en s"rface into !eep scratchlines on the s"rface. They are a!e of steel &ith a sharp point at one en! an! flat bla!e at the other en!.

Fig. Marking Kni"e

Fig. #r$ S%uare

Be<e: SD-are> it is also calle! sli!ing level. t is an a!j"stable trys("are

for eas"ring@ar$ing angles bet&een DD an! 18D

D.

2I Ho:@ing too:,

a5 'or Ben7

This is a table of having siCe an! raise! constr"ction a!e of har! &oo!.The siCe ranges fro 5D 8D c in length an! abo"t 9Dc in &i!th. T&o

Fig. &eve' S%uare

or fo"r carpenters can &or$ at a tie on the &or$ bench.

Carpenter, Ben7 2ie

t consists of ja& fixe! on the table si!e an! ovable ja&

$ept in position by eans of scre& an! han!le. The

bo!y of vice is a!e of cast iron or steel. The ja&s are

line! &ith har! &oo! &hich can be reove! &hen it is

!aage!.

Fig. (ork &en* +i* &en* HookThe scre& oves insi!e the fixe! half n"t &hich can be

engage! or !isengage! by operating the lever. This is a!e "p of a bar of steel. The &or$ is clape! bet&een ja&s by rotating the scre& "sing the han!le. t is "se! for claping gl"e! pieces or hol!ing the&or$ piece of larger siCe together for vario"s operations.

a5 Sa,79ramp

Page 15




b+ C C:amp> The clap of the shape of letter % or B is "se! to clap short pieces together as the bar clap. These claps are available is siCes varying fro 7D to 8DD . it is "se! for hol!ing the plan$s after gl"ing

Fig. ,arener! &en* ieFig. ,- ,'a/ Fig. &ar or #-,ra/

Bar or T9ramp> it consists of a steel bar fitte! &ith a threa!e! spin!le an! an a!j"stable shoe. t is "se! forhol!ing the gl"e! pieces tightly or hol!ing firly t&o or ore "ngl"e! pieces for fitting !o&els or !oing otheroperations on the in asseble! position.

II C-tting too:, a5 Sa?,

a& is a c"tting tool &hich has teeth on one e!ge an! c"tting is affecte! by reciprocating otion of thee!ge relative to the &or$ piece. %"tting occ"rs !"ring the for&ar! otionH s"ch a sa& is calle! p"sh type sa&the c"tting occ"rs !"ring the bac$&ar! otion.

i. /an! a& This sa& is "se! for short straight c"ts. t has a bla!e of 254Dc length 61Dc &i!th.The n"ber of teeth per c length ranges fro 35.

ii. Tenon a& )ac$ a&+ t has a parallel bla!e of 254Dc length an! 61Dc &i!th. The n"ber of teeth per c length ranges fro 58.

05 C7i,e:,

The coon type of chisels "se! is briefly explaine! belo&.

i. irer %hisels they are ost coon an! general p"rpose chisel "se! by a carpenter. They have flat bla!e of 155D &i!th an! 125 length.

ii. -ove Tail %hisel )bevele! e!ge firer chisel+ These chisels are "se! for fine an! !elicate &or$s as &ellas for c"tting corners.

iii.ortise chisel J These chisels are "se! for heavy an! !eep c"t to reove large ("antity of &oo!. These

chisels have &i!th of abo"t 15 b"t the bla!e thic$ness ay range fro 615.

Page 16




Fig. Sa+!

Fig. Par! o" a ,*i!e'

Fig. ,ro!!-u Sa+Fig. i Sa+

Fig. Par! o" Sa+

Fig. #$e! o" ,*i!e'!

III P:aning Too:,




:laning tool is "se! to soothen the &oo!en s"rfaces.

a5 'oo@en ;a p:ane

This is the ost coonly "se! plane in carpentry shop. The ain part of a &oo!en jac$ plane is a &oo!en bloc$ calle! sole in &hich steel bla!e having $nife e!ge is fixe! at an angle &ith the help of &oo!en e!ge.

The angle of the bla!e is $ept abo"t 45 E to botto s"rface of the bla!e.

05 Meta: 3a P:ane

t serves the sae p"rpose as the &oo!en jac$ plane b"tfacilitates a soother operations an! better finish. The

bo!y of a etal jac$ plane is a!e fro a grey ironcasting &ith the si!e an! sole achine! an! gro"n! to

better finish.

-0??=B ,=- ;0=B T;;?

a5 Bra@a?:> t is a han! operate! tool "se! to bore sall holes for starting a scre& or large nail.

Fig. Gi/'e ri''

b+ Carpenter, 0rae> it is "se! for rotating a"ger bits

t&ist !rills etc. to pro!"ce holes in &oo!. n soe !esigns braces are a!e &ith ratchet !evice.

c+ A-ger 0it> it is the ost coon tool "se! for a$ing holes in &oo!. -"ring !rilling the lea!scre& of the bit g"i!es into the &oo! necessitating only o!erate press"re on the brace. Thehelical fl"tes on the s"rface carry the chips to the o"ter s"rface.

!+ Han@ @ri::> carpenterFs brace is "se! to a$e relatively large siCe holesH &hereas han! !rill is"se! for !rilling sall holes. , straight shan$ !rill is "se! &ith this tool. t is sall light in&eight an! ay be conveniently "se! than the brace. The !rill bit is clape! in the ch"c$ at itsen! an! is rotate! by a han!le attache! to gear an! pinion arrangeent.

e+ Bilet it has c"tting e!ges li$e a t&ist !rill. t is "se! for !rilling large !iaeter holes &ith thehan! press"re.

Striing Too:,

a5 Ma::et

This is &oo!en hea!e! haer of ro"n! or rectang"lar section.The stri$ing face is a!e flat. allet is "se! for the c"tting toolsan! has &oo!en han!le.

05 C:a? Hammer

This is a haer having steel hea! an! &oo!en han!le. The flat face of the hea! an! cla& portion for extracting nails o"t of the &oo!.

crossstri$ing

Fig. Ma''e

Page 18

Fig. P'ane




Fig. Piner

Fig. ,'a+ Ha//er

5 Piner> it is a!e of t&o forge! steel ars &ith a hinge! joint an! is "se! for p"llingo"t sall nails fro&oo!. The inner faces of the pincer ja&s are bevelle! an! the o"ter faces are plain. The en! of one arhas a ball an! the other has a cla&. The bevelle! ja&s an! the cla& are "se! for p"lling o"t sall nails

pins an! scre&s fro the &oo!.

@5 Sre? %ri<er> it is "se! for !riving &oo! scre&s into &oo! or "nscre&ing the. The length of a scre&!river is !eterine! by the length of the bla!e. ,s the length of the bla!e increases the &i!th an!thic$ness of the tip also increase.

Fig. Sre+ river

'oo@ ra,p /i:e,> it is a finishing tool "se! to a$e the &oo! s"rface sooth reove sharp e!ges an!finish fillets an! other interior s"rfaces. harp c"tting teeth are provi!e! on its s"rface for the p"rpose.This file is excl"sively "se! in &oo! &or$.

Fig. (oo a! 'e!

Page 19




E=PT.NO>1 %O2ETAIL LAP 3OINT %ATE>

,to a$e a !ovetail lap joint.

,T0,? 0K>0- Tea$ &oo! )3DL15DL5D+

T;;? ,=- K>:=T

>-1. teel r"le

2. Try s("are

3. ar$ing g"age

4. 0ip sa&

5. Tenon sa&

6. ortise chisel

7. allet

8. <ac$ plane

9. #oo! rasp file

;:0,T;= T; %,00-;>T

1. :lanning

2. ar$ing

3. a&ing

4. %hiseling

5. inishing

:0;%->0

1. The &oo!en pieces are a!e into t&o halves an! are chec$e! for !iensions.

2. ;ne si!e of pieces is planne! &ith jac$ plane an! for strraightness.

3. ,n a!ajacent si!e is planne! an! chec$e! for s("areness &ith a try s("are.

4. ar$ing g"age is set an! lines are ar$e! at 4D5D to a$e the thic$ness an! &i!thaccor!ing to given fig"re.

5. The excess aterial is planne! to correct siCe.

6. >sing tenon sa& the portions to be reove! are c"t in both the pieces

7. The excess aterial in M is chisele! &ith ortise chisel.

8. The excess aterial in ' in chisele! to s"it M

9. The en! of both the pieces is chisele! to exact lengths.

:0%,>T;=

1. #oo! sho"l! be free fro oist"re

2. ar$ing is !one &ith o"t parallax error3. %are sho"$! be ta$en &hile chiseling

4. atching of M an! ' pieces sho"l! be tight.

0>?T

The !ovetail lap joint is a!e s"ccess f"lly.

E=PT.NO># CROSS HAL! LAP 3OINT %ATE>

,to a$e a cross half lap joint.

,T0,? 0K>0- Tea$ &oo! )3DL15DL5D+

T;;? ,=- K>:=T >-

Page 20




1. teel r"le

2. Try s("are

3. ar$ing g"age

4. 0ip sa&

5. Tenon sa&

6. ortise chisel7. allet

8. <ac$ plane

9. #oo! rasp file

;:0,T;= T; %,00- ;>T

1. :lanning

2. ar$ing

3. a&ing

4. %hiseling5. inishing

:0;%->0

1. The &oo!en pieces are a!e into t&o halves an! are chec$e! for !iensions.

2. ;ne si!e of pieces is planne! &ith jac$ planean! for strraightness.

3. ,n a!ajacent si!e is planne! an! chec$e! for s("areness &ith a try s("are.

4. ar$ing g"age is set an! lines are ar$e! at 4D5D to a$e the thic$ness an! &i!thaccor!ing to given fig"re

5. The excess aterial is planne! to correct siCe.

6. >sing tenon sa& the portions to be reove! are c"t in both the pieces

7. The excess aterial in M is chisele! &ith ortise chisel.

8. The excess aterial in ' in chisele! to s"it M

9. The en! of both the pieces is chisele! to exact lengths.

:0%,>T;=

1. 0eaper sho"l! be free fro oist"re

2. ar$ing is !one &ith o"t parallax error

3. %are sho"$! be ta$en &hile chiseling

4. atching of x an! y pieces sho"l! be tight.

0>?T The cross half lap joint is a!e s"ccess f"lly.

Page 21




!ITTIN"

The ter fitting is relate! to assebly of parts after bringing the !iension or shape to the re("ire!siCe or for in or!er to sec"re the necessary fit. The operations re("ire! for the sae are "s"ally carrie!o"t on a &or$ bench hence the ter bench work is also a!!e! &ith the nae fitting.

The bench &or$ an! fitting plays an iportant role in engineering. ,ltho"gh in to!ayNs in!"stries

ost of the &or$ is !one by a"toatic achines &hich pro!"ces the jobs &ith goo! acc"racy b"t still it

)job+ re("ires soe han! operations calle! fitting operations. The person &or$ing in the fitting shop is

calle! fitter

!ITTIN" TOOLS>

itting shop tools are classifie! as belo&

• #or$ /ol!ing -evices@ %laping Tools.

• eas"ring an! ar$ing Tools.

• %"tting Tools.

• tri$ing Tools.

• -rilling Tools.• Threa!ing Tools.

I. 'ORK HOL%IN" %E2ICES 8CLAMPIN" TOOLS>

1. 'or Ben7

, fitting process can be !one at vario"s places b"t ostof the iportant operations of fitting are generallycarrie! o"t on a table calle! work bench.

The &or$ bench is a strong heavy an! rigi! table a!e"p of har! &oo!.

The siCe of the &or$ bench re("ire! is abo"t 15D to 18Dc length nearly 9D c &i!th an! approxiately 76 to84 c height.

#. BENCH 2ICE>

t is firly fixe! to the bench &ith the help of n"ts an! bolts. t consists of a cast ron bo!y an! cast

iron ja&s. T&o ja& plates are fitte! on both the ja&s. The hol!ing s"rface of the ja& plates is $n"rle! in

or!er to increase the gipping. <a& plates are a!e "p of carbon steel an! are &ear resistant. ;ne ja& is

fixe! to the bo!y an! the secon! sli!es on a s("are threa!e! scre& &ith the help of a han!le.

The ja&s are opene! "pto re("ire! lengthH job is place! in the t&o ja&s an! is f"lly tightene! &ith the

help of han!le. /an!le is "se! to ove the ovable ja&

Page 22




. 2 B:o

n loc$ grooves are provi!e! to hol! the ro"n! objects longit"!inally. The scre& of theclap applies the hol!ing press"re. #hen the han!le is rotate! there is oveent in the scre&.

II. MEAS$RIN" TOOLS

1. Stee: R-:e

These are a!e "p of stainless steel an! are available in any siCes ranging fro 1@2 ft. to 2 ft. Theseare ar$e! in inches or illietres. ,ll the faces are achine! tr"e. The e!ges of steel r"le sho"l! be

protecte! fro ro"gh han!ling.

#. Ca:iper,

These are generally "se! to eas"re the insi!e or o"tsi!e !iaeters. -ifferent types are

i. ;"tsi!e %aliper t is "se! to eas"re the o"tsi!e !iensions.

ii. nsi!e %aliper t is "se! to eas"re the insi!e !iensions.

iii. pring %aliper pring is provi!e! to apply the press"re an! loc$ n"t is provi!e! to loc$ any!esire! position.

iv. /eraphro!ite <enny or ;!!leg %aliper ;ne leg is bent at the tip in&ar!ly an! the other has astraight pointe! en!. t is "se! to scribe lines parallel to the straight e!ges.

Fig. ,a'ier!

3. ernier %aliper t is "se! for eas"ring the o"ter !iensions of ro"n! flat s("are coponents an!also the inner siCe of the holes an! bore. , narro& bla!e is "se! to eas"re the !epth of bar slots etc. Therea!ing acc"racy in etric syste is D.D2 an! ritish syste it is D.DD1O. t is a!e of stainless steel.

Page 23




III. MARKIN" TOOLS>

1. S-r/ae P:ate

t is "se! for testing the flatness tr"eness of the

s"rfaces. t is a!e "p of cast iron or graphite. ts "pper

face is plane! to for a very sooth s"rface. t is also"se! in scribing &or$.

#hile not in "se it sho"l! be covere! &ith a&oo!en cover.

#. Ang:e P:ate

t is a!e "p of cast iron in !ifferent siCesH it has t&o plane! s"rfacesat right angles to each other an! has vario"s slots in each s"rface tohol! the &or$ by eans of bolts an! claps.

=ever !o haering on the angle plate to fasten )lighten+ then"ts an! bolts.

. Sri0er an@ S-r/ae "a-ge

t consists of a cast iron bass on the center of &hich a steel ro! is fixe! vertically. criber is a!e"p of high carbon steel an! is har!ene! fro the front e!ge. t is "se! for locating the centres ofro"n! bars or for ar$ing of the lines.

Fig. Srier an Sur"ae Gauge&. P-n7e,

:"nches are "se! for ar$ing p"rposes. -ot p"nches are "se! for ar$ing !otte! line an! centre

p"nch is "se! to ar$ the centre of hole before !rilling. :"nches are a!e "p of high carbon

steel or high spee! steels. ;ne en! is sharpene!. /aering is !one on the secon! en! &hile

&or$ing. or !ot p"nch angle of the p"nching en! is 6D !egree &hile in centre p"nchH angle of

p"nching en! is 9D !egree.

Page 24



Engineering Work Shop Department of Mechanical Engineering

(. Tr SD-are

t is "se! for chec$ing s("areness of t&o s"rfaces. t consists of a bla!e

a!e "p of steel &hich is attache! to a base at 9D !egree. The base is

a!e "p of cast iron or steel. t is also "se! to ar$ the right angles an!

eas"ring straightness of s"rfaces. =ever "se try s("are as a haer.

6. 2ernier Heig7t ga-ge>

A ernier height ga"ge consists of a heavy base a gra!"ate! bea a

sli!ing hea! &ith ernier sli!ing ja&s hol!ing the scriber an! a fine

a!j"stent clap. t is siilar to large ernier calipers in constr"ction

except that it consists of a heavy base &hich allo&s the ga"ge to stan!

"pright instea! of a fixe! ja& in a ernier. The ovable ja& of ernier

height ga"ge consists of a projection or extension &hich is levelle! to

sharp e!ge for scribing lines at any re("ire! height.

METHO% O! MARKIN"

ar$ing eans setting o"t !iensions &ith the help of a &or$ing!ra&ing or !irectly transferring the fro a siilar part. The proce!"reof ar$ing is as follo&s

1. The s"rface to be ar$e! is coate! &ith the paste of chal$ or re!lea! an! allo&e! to !ry.2. Then the &or$ is hel! n a hol!ing !evice !epen!ing "pon shape

an! siCe. f it is flat "se s"rface plate if it is ro"n! "se bloc$ an! clap else "se angle plateetc.

3. ?ines in horiContal !irection are scribe! by eans of a s"rface ga"ge. ?ines at right angles can be!ra&n by t"rning the &or$ thro"gh 9D !egree an! then "sing the scriber. f tr"e s"rface isavailable try s("are can also be "se!.

4. The centre on the en! of a ro"n! bar can be locate! by "sing an o!! leg caliper s"rface ga"ge etc.

5. The circles an! arcs on a flat s"rface are ar$e! by eans of a !ivi!er.

6. ,fter the scribing &or$ is over in!entations on the s"rface are a!e "sing !ot p"nch an!haer.

I2. C$TTIN" TOOLS

1. Ha,a?/ac$sa& is "se! for c"tting of

ro!s bars pipes flats etc. t

consists of a frae &hich is

a!e fro il! steel. The

bla!e is place! insi!e the

frae an! is tightene! &ith

the help of a flange n"t. The

bla!e is a!e "p of high

carbon steel or high spee! Fig. Han2

Ha)k!a+!steel.

Fig. ernier *eig*gauge -Fine u!/en o"nu &-ernier!'ie ,-Srier 'a/ !re+ 7 Srier

7 ernier Sa'e F 7 Main Sa'e G7 &a!e :; 7 <ok Sre+!



The points of the teeth are bent in a CigCagfashion to c"t a &i!e groove an! prevent the bo!y




of the bla!e fro r"bbing or jaing in the sa& c"t. The teeth of the bla!es are generally for&ar! c"t soin the case press"re is applie! in the for&ar! !irection only.

-epen!ing "pon the !irection of c"t bla!es are classifie! aso or&ar! c"to ac$&ar! c"t.

-epen!ing "pon the pitch of the teeth )-istance bet&een the t&o consec"tive teeth+ bla!es is classifie! as• %oarse )814 teeth per nch+

• e!i" )162D teeth per inch+

• ine )2432 teeth per inch+

#. !i:e,

iles are "lti points c"tting tools. t is "se! to reove the aterial by r"bbing it on the etals. iles are available in a n"ber of siCesshapes an! !egree of coarseness.

C:a,,i/iation o/ /i:e,

i. On t7e 0a,i, o/ :engt7

&61#

ii. On t7e 0a,i, o/ gra@e>• 0o"gh )0+)2D teeth per inch+

• astar! )+)3D teeth per inch+

• econ! c"t )c+ )4D teeth per inch+

• ooth file )+)5D teeth per inch+

• -ea! sooth )-+)1DD teeth per inch+

0o"gh an! bastar! files are the big c"t files. #hen the aterial reoval is ore these files are "se!.These files have bigger c"t b"t the s"rface pro!"ce! s ro"gh.

-ea! sooth an! sooth files have saller teeth an! "se! for finishing &or$. econ! c"t file has!egree of finish in bet&een bastar! an! sooth file.

i<. On t7e 0a,i, o/ n-m0er o/ -t,>

• ingle c"t files.• -o"ble c"t files.

• 0asp files.

n single c"t files the teeth are c"t in parallel ro&s at an angle of 6D !egree to the face. ,nother ro& of teeth is a!!e! in opposite !irection in case of !o"ble c"t files. aterial reoval is ore in case of!o"ble c"t files.

iii. On t7e 0a,i, o/ ,7ape an@ ,iFe>The length of the files varies fro 4N to 14L. The vario"s shapes of crosssection available are han!file flat file triang"lar ro"n!H s("are half ro"n! $nifee!ge pillar nee!le an! ill file.

Page 26




a. !:at /i:e> This file has parallel e!ges for abo"t t&othir!s of the length an! then it tapers in &i!than! thic$ness. The faces are !o"ble c"t &hile the e!ges are single c"t.

b. Han@ /i:e> for a han! file the &i!th is constant thro"gho"t b"t the thic$ness tapers as given in flatfile. oth faces are !o"ble c"t an! one e!ge is single c"t. The reaining e!ge is $ept "nc"t inor!er to "se for filing a rightangle! corner on one si!e only.

c.SD-are /i:e>

t has a s("are crosssection. t is parallel for t&othir!s of its length an! then tapersto&ar!s the tip. t is !o"ble c"t on all si!es. t is "se! for filing s("are corners an! slots.

!. Triang-:ar /i:e> t has &i!th either parallel thro"gho"t or "pto i!!le an! then tapere! to&ar!sthe tip. ts section is triang"lar )e("ilateral+ an! the three faces are !o"ble c"t an! the e!ges singlec"t. t is "se! for filing s("are sho"l!ers or coers an! for sharpening &oo! &or$ing sa&s.

e. Ro-n@ /i:e> t has ro"n! crosssection. t carries single c"t teeth all ro"n! its s"rface. t isnorally a!e tapere! to&ar!s the tip an! is fre("ently $no&n as rattail file. :arallel ro"n! fileshaving sae !iaeter thro"gho"t the length are also available. The ro"n! files are "se! for opening o"t holes pro!"cing ro"n! coers ro"n!en!e! slots etc.

f. Ha:/9ro-n@ /i:e> ts crosssection is not a tr"e half circle b"t is only abo"t onethir! of a circle.The &i!th of the file is either parallel thro"gho"t or "pto i!!le an! then tapere! to&ar!s the tip.The flat si!e of this file is al&ays a !o"ble c"t an! c"rve! si!e has single c"t. t is "se! for filingc"rve! s"rfaces.

g. Kni/e e@ge /i:e> t has a &i!th tapere! li$e a $nife bla!e an! it is also tapere! to&ar!s the tip an!thic$ness. t carries !o"ble c"t teeth on the t&o broa! faces an! single c"t teeth on the e!ge. t is"se! for finishing sharp corners of grooves an! slots

h. %iamon@ /i:e> ts crosssection is li$e a !iaon!. t is "se! for special &or$.

i. Nee@:e /i:e> These are thin sall files having a parallel tang an! a thin narro& an! pointe! bla!ea!e in !ifferent shapes of its crosssection to s"it the partic"lar nee! of the &or$. These areavailable in siCes fro 1DD to 2DD of vario"s shapes an! c"ts. These files are "se! for filing very thin an! !elicate &or$.

Met7o@, o/ /i:ing

The follo&ing are the t&o coonly "se! etho!s of filing1. %rossfiling 2. -ra& filing.Cro,, 9 /i:ing. Re/er !ig. 4a5.

This etho! is "se! for efficient reoval of axi" ao"nt of etal in the shortest possible tie. t ay be note! that the file "st reainhoriContal thro"gho"t the stro$e )long slo& an! stea!y+ &ith press"re onlyapplie! on the for&ar! otion.

%ra? /i:ing. Re/er !ig. 405

This etho! is "se! to reove file ar$s an! for finishing operations. /ere thefile is grippe! as close to the &or$ as possible bet&een t&o han!s. n this filingetho! a fine c"t file &ith a flat face sho"l! be "se!.

!ILE CAR%>

t is a !evice fashione! li$e a &ire br"sh "se! to clean !irt an! chipsfro the teeth of a file. #hen particles of etal clog the teeth the file issai! to the pinned a con!ition that ca"ses scratching of the s"rface of the &or$. iles therefore re("ire cleaning by eans of a file car! or

by !islo!ging the aterial bet&een the teeth by eans of a piece of soft iron copper brass tin plate an! so on sharpene! at the en!./ar!ene! steel sho"l! never be "se!

Fig. Fi'e ,ar

Page 2=




Page 28




E=PT.NO> )1 SG$ARE C$TTIN" %ate AIM> To a$e a ("are fit fro the given i!steel pieces.MATERIALS REG$IRE%> il! steel flat )4DL4DL3+.

TOOLS AN% EG$IPMENT REG$IRE%>

1.6Otry s("are

2. 6Osriber

3. ;!! leg caliper

3.12Ohac$ sa& rae

4 la!es )12 T:+

5. 1DOro"gh file

6. 1DOsooth file

7. 1DO("are file

8. -ot p"nch

9. all peen haer )D.5 b+.1D. teel 0"le

SeD-ene o/ OPERATIONS>

1. illing

2. ar$ing

3. :"nching

4. a&ing

5. illing

6. inishing

PROCE%$RE>1. The given il! steel flat piece is chec$e! for given !iensions.

2. ;ne e!ge of given is fille! to straightness &ith ro"gh an! sooth files an! chec$e! &ith try s("are.

3. ,n a!jacent is also fille! s"ch that is s("are to first e!ge an! chec$e! &ith try s("are.

4. #et chal$ is applie! on one si!e of the flat an! !rie! for a$ing.

5. ?ines are ar$e! accor!ing to given fig"re "sing o!! leg caliper an! steel r"le.

6. "sing the !ot p"nch are a!e along the ar$e! lines.

7. The excess aterials reove! fro the reaining t&o e!ges &ith try s("are level "p to half of thear$e! !ots.

8. inally b"ts are reove! by the filling on the s"rface of the fitte! job.

:0%,>T;=1. The perpen!ic"larity of face en!s e!ges is chec$e! perfectly by "sing try s("are.

2. inishing is given by "sing only &ith sooth files.

3. ar$ing is !one &itho"t parallax error.

0>?T The ("are c"tting is !one s"ccessf"lly

Page 29




E=PT.NO> D2 29!ITTIN"

AIM> To a$e a it fro the given i! steel pieces. MATERIALS REG$IRE% il! steel flat )4DL4DL3+.TOOLS AN% EG$IPMENT REG$IRE%>

1.6Otry s("are

2. 6Osriber

3. ;!! leg caliper

3.12Ohac$ sa& rae

4 la!es )12 T:+

5.1DOro"gh file

6.1DOsooth file

7.1DOtriangle file

8. Anife !ge file

9. -ot p"nch

1D. all peen haer )D.5 b+

11. teel 0"le

SeD-ene o/ Operation,>

1. illing

2. ar$ing

3. :"nching

4. a&ing

5. illing

6. inishing

PROCE%$RE>1. The given il! steel flat piece is chec$e! for given !iensions.

2. ;ne e!ge of given is fille! &ith ro"gh an! sooth files an! chec$e! &ith try s("are for straightness.

3. ,n a!jacent e!ge is also fille! s"ch that it is s("are to first e!ge an! chec$e! &ith try s("are.

4. #et chal$ is applie! on one si!e of the flat an! !rie! for ar$ing.

5. ?ines are ar$e! accor!ing to given fig"re "sing o!! leg caliper an! steel r"le.

6. >sing the !ot p"nch p"nches are a!e along the ar$e! lines.

7. The excess aterials reove! fro the reaining t&o e!ges &ith try s("are level "p to half of the ar$e! !ots.

8. inally b"ts are reove! by the filling on the s"rface of the fitte! job.

PRECA$TIONS>

1. The perpen!ic"larity of face en!s e!ges is chec$e! perfectly by "sing try s("are.

2. inishing is given by "sing only &ith sooth files.

3. ar$ing is !one &itho"t parallax error.

RES$LT>

The fit is !one s"ccessf"lly.

Page 30




!O$N%RY

PATTERN

, pattern is a o!el or the replica of the object )to be caste!+. t is ebe!!e! in ol!ing san! an! s"itableraing of ol!ing san! aro"n! the pattern is a!e. The pattern is then &ith!ra&n for generating cavity

)$no&n as ol!+ in ol!ing san!.

COMMON PATTERN MATERIALS

The coon aterials "se! for a$ing patterns are &oo! etal plastic plaster &ax or erc"ry.

TYPES O! PATTERN

The types of the pattern an! the !escription of each are given as "n!er.

1. ;ne piece or soli! pattern 2. T&o piece or split pattern 3. %ope an! !rag pattern 4. Threepiece or "lti piece pattern 5. ?oose piece pattern 6. atch plate pattern 7. ollo& boar! pattern 8. Bate! pattern9. &eep pattern 1D. $eleton pattern 11. egental or part pattern

1. Sing:e9piee or ,o:i@ pattern> oli! pattern is a!e of single piece &itho"t joints partings lines or loose pieces. t is the siplest for of the pattern. Typical single piece pattern is sho&n in ig. 1D.1.

#. T?o9piee or ,p:it pattern> #hen soli! pattern is !iffic"lt for &ith!ra&al fro the ol! cavity then

soli! pattern is split in t&o parts. plit pattern is a!e in t&o pieces &hich are joine! at the parting line by

eans of !o&el pins. The splitting at the parting line is !one to facilitate the &ith!ra&al of the pattern. ,

typical exaple is sho&n in ig. 1D.2

Fig. Sing'e PieePaern

Fig. #+o Pie)ePaern

MOL%IN" SAN%

The general so"rces of receiving ol!ing san!s are the be!s of sea rivers la$es gran"lar eleents of roc$s an! !eserts.

ol!ing san!s ay be of t&o types naely nat"ral or synthetic. =at"ral ol!ing san!s contain s"fficient

bin!er. #hereas synthetic ol!ing san!s are prepare! artificially "sing basic san! ol!ing constit"ents

)silica san! in 8892G bin!er 612G &ater or oist"re content 36G+ an! other a!!itives in proper proportion by &eight &ith perfect ixing an! "lling in s"itable e("ipents.

Bin@er

n general the bin!ers can be either inorganic or organic s"bstance. The inorganic gro"p incl"!es clay

so!i" silicate an! port lan! ceent etc. n fo"n!ry shop the clay acts as bin!er &hich ay be Aaolonite

all %lay ire %lay ?ionite "llerFs earth an! entonite. in!ers incl"!e! in the organic gro"p are

!extrin olasses cereal bin!ers linsee! oil an! resins li$e phenol foral!ehy!e "rea foral!ehy!e etc.

;rganic bin!ers are ostly "se! for core a$ing.

,ong all the above bin!ers the bentonite variety of clay is the ost coon. /o&ever this clay alonecannot !evelop bon!s aong san! grins &itho"t the presence of oist"re in ol!ing san! an! core san!.

A@@iti<e,

Page 31




,!!itives are the aterials generally a!!e! to the ol!ing an! core san! ixt"re to !evelop soe special property in the san!. oe coon "se! a!!itives for enhancing the properties of ol!ing an! coresan!s are !isc"sse! as "n!er.

1. Coa: @-,t> %oal !"st is a!!e! ainly for pro!"cing a re!"cing atosphere !"ring casting.

#. Corn /:o-r> t belongs to the starch faily of carbohy!rates an! is "se! to increase the collapsibilityof the ol!ing an! core san!

. %extrin> -extrin belongs to starch faily of carbohy!rates that behaves also in a anner siilar tothat of the corn flo"r. t increases !ry strength of the ol!s.

&. Sea oa:> ea coal is the fine po&!ere! bit"ino"s coal &hich positions its place aong the pores of the silica san! grains in ol!ing san! an! core san!

(. 'oo@ /:o-r> This is a fibro"s aterial ixe! &ith a gran"lar aterial li$e san!H its relatively longthin fibers prevent the san! grains fro a$ing contact &ith one another.

6. Si:ia /:o-r> t is calle! as p"lveriCe! silica an! it can be easily a!!e! "p to 3G &hich increases thehot strength an! finish on the s"rfaces of the ol!s an! cores

KIN%S O! MO$L%IN" SAN%

ol!ing san!s can also be classifie! accor!ing to their "se into n"ber of varieties &hich are !escribe! belo&.

1. "reen ,an@> Breen san! is also $no&n as tepere! or nat"ral san! &hich is a j"st prepare! ixt"reof silica san! &ith 18 to 3D percent clay having oist"re content fro 6 to 8G. The clay an! &ater f"rnish the bon! for green san!. t is fine soft light an! poro"s.

#. %r ,an@> Breen san! that has been !rie! or ba$e! in s"itable oven after the a$ing ol! an! coresis calle! !ry san!. t possesses ore strength rigi!ity an! theral stability.

. Loam ,an@> ?oa is ixt"re of san! an! clay &ith &ater to a thin plastic paste. ?oa san! possesseshigh clay as "ch as 3D5DG an! 18G &ater.

&. !aing ,an@> acing san! is j"st prepare! an! fors the face of the o"l!. t is !irectly next to the

s"rface of the pattern an! it coes into contact olten etal &hen the o"l! is po"re!. nitial coatingaro"n! the pattern an! hence for ol! s"rface is given by this san!. This san! is s"bjecte! severest

con!itions an! "st possess therefore high strength refractoriness.

(. Baing ,an@> ac$ing san! or floor san! is "se! to bac$ "p the facing san! an! is "se! to fill the&hole vol"e of the ol!ing flas$.

6. Parting ,an@> :arting san! &itho"t bin!er an! oist"re is "se! to $eep the green san! not to stic$ tothe pattern an! also to allo& the san! on the parting s"rface the cope an! !rag to separate &itho"tclinging

+. Core ,an@> %ore san! is "se! for a$ing cores an! it is soeties also $no&n as oil san!. This ishighly rich silica san! ixe! &ith oil bin!ers s"ch as core oil &hich copose! of linsee! oil resinlight ineral oil an! other bin! aterials.

PROPERTIES O! MO$L%IN" SAN%

The basic properties re("ire! in ol!ing san! an! core san! are !escribe! as "n!er.

1. Re/ratorine,,> 0efractoriness is !efine! as the ability of ol!ing san! to &ithstan! highteperat"res &itho"t brea$ing !o&n or f"sing th"s facilitating to get so"n! casting. t is a highlyiportant characteristic of ol!ing san!s. 0efractoriness can only be increase! to a liite! extent

#. Permea0i:it> t is also tere! as porosity of the ol!ing san! in or!er to allo& the escape of any air

gases or oist"re present or generate! in the o"l! &hen the olten etal is po"re! into it. ,ll these

gaseo"s generate! !"ring po"ring an! soli!ification process "st escape other&ise the casting

becoes !efective

. Co7e,i<ene,,> t is property of ol!ing san! by virt"e &hich the san! grain particles interact an!attract each other &ithin the ol!ing san!

Page 32




&. "reen ,trengt7> The green san! after &ater has been ixe! into it "st have s"fficient strength an!to"ghness to perit the a$ing an! han!ling of the o"l!. or this the san! grains "st be a!hesivei.e. thev "st be capable of attaching theselves to another bo!y

(. %r ,trengt7> ,s soon as the olten etal is po"re! into the o"l! the oist"re in the san! layer a!jacent to the hot etal gets evaporate! an! this !ry san! layer "st have s"fficient strength to its

shape in or!er to avoi! erosion of o"l! &all !"ring the flo& of olten etal6. !:o?a0i:it or p:a,tiit> t is the ability of the san! to get copacte! an! behave li$e a fl"i!. t &ill

flo& "niforly to all portions of pattern &hen rae! an! !istrib"te the raing press"re evenly allaro"n! in all !irections

+. A@7e,i<ene,,> t is property of ol!ing san! to get stic$ or a!here &ith foreign aterial s"ch stic$ingof ol!ing san! &ith inner &all of ol!ing box

. Co::ap,i0i:it> ,fter the olten etal in the o"l! gets soli!ifie! the

san! o"l! "st be collapsible so that free contraction of the etal

occ"rs an! this &o"l! nat"rally avoi! the tearing or crac$ing of the

contracting etal.

HAN% TOOLS $SE% IN !O$N%RY SHOP

Han@ ri@@:e> t consists of a screen of stan!ar! circ"lar &ire esh

e("ippe! &ith circ"lar &oo!en frae. t is generally "se! for

cleaning the san! for reoving foreign aterial s"ch as nails shot

etal splinters of &oo! etc. fro it. ven po&er operate! ri!!les are

available for ri!!ling large vol"e of san!.

S7o<e:> t consists of a steel pan fitte! &ith a long &oo!en han!le. t

is "se! in ixing tepering an! con!itioning the fo"n!ry san! by

Fig.S*o+e'

han!. t is also "se! for oving an! transforing the ol!ing san! to

the container an! ol!ing box or flas$.

Fig. Srue PinFig. a//er!

Rammer,> 0aers are sho&n in ig. These are re("ire! for stri$ing the ol!ing san! ass in the ol!ing box to pac$ or copact it "niforly all aro"n! the pattern.

Spr-e pin> t is a tapere! ro! of &oo! or iron &hich is place! or p"she! in cope to join ol! cavity &hilethe ol!ing san! in the cope is being rae!.

Tro?e:,> These are "se! for finishing flat s"rfaces an! coers insi!e a o"l!. %oon shapes of tro&elsare sho&n as "n!er. They are a!e of iron &ith a &oo!en han!le.

Li/ter> , lifter is a finishing tool "se! for repairing the o"l! an! finishing the o"l! san!. ?ifter is also

"se! for reoving loose san! fro o"l!.

Strie o// 0ar> t is a flat bar a!e of &oo! or iron to stri$e off the

excess san! fro the top of a box after raing.

tFs one e!ge a!e bevele! an! the s"rface perfectly sooth

an! plane.

2ent ?ire> t is a thin steel ro! or &ire carrying a pointe! e!ge

at one en! an! a &oo!en han!le or a bent loop at the other. ,fter raing an!stri$ing off the excess san! it is "se! to a$e sall

Fig. <i"er

Fig. Srike o>ar



Fig. en (ire




holes calle! vents in the san! o"l! to allo& the exit of gases an! stea !"ring casting.

S:i,> They are also recogniCe! as sall !o"ble en!e! ol! finishing tool &hich are generally "se! for

repairing an! finishing the ol! s"rfaces an! their e!ges after &ith!ra&al of the patternFig. S'ik!

S?a0> &ab is sho&n in ig. 11.1)"+. t is a sall hep fiber br"sh "se! for

oistening the e!ges of san! o"l! &hich are in contact &ith the pattern s"rface before &ith!ra&ing the pattern. t is "se! for s&eeping a&ay the ol!ing san!fro the ol! s"rface an! pattern.

Fig. S+a

"ate -tter> Bate c"tter )ig. 11.1)v++ is a sall shape! piece of sheet

etal coonly "se! to c"t r"nners an! fee!ing gates for connecting

spr"e hole &ith the ol! cavity.Fig. Gae ,uer

Be::o?,> ello&s g"n is sho&n in ig. 11.1)&+. t is han! operate! leather a!e !evice e("ippe! &ith copresse!air jet to blo& or p"p air &hen operate!. t is "se! to blo& a&ay the loose or "n&ante! san! fro the s"rfaces of ol! cavities.

%ra? ,pie> -ra& spi$e is sho&n ig. 11.1)f+. t is a tapere! steel ro!having a loop or ring at its one en! an! a sharp point at the other. t ay

have scre& threa!s on the en! to engage etal pattern for it &ith!ra&al

fro the ol!.

Spr-e Pin t is a tapere! &oo!en pin "se! to a$e a hole in the copethro"gh &hich the olten etal is po"re! into the o"l!.

MO$L%IN" BO=>

o"l!ing box is also calle! o"l!ing flas$. t is frae or box of &oo! or etal. t is a!e of t&o parts cope an!!rag as sho&n in fig"re.

Page 34



Engineering Work Shop

Department of Mechanical

Engineering

E=P> )1 MO$L% !OR A SOLI% %ate>

Aim> To prepare a san! ol! "sing the given single piece pattern.

Ra? materia: reD-ire@> o"l!ing san! :arting san! facing san! ba$ing san! single piece soli!

pattern botto boar! o"l!ing boxes etc.

Too:, ReD-ire@>

1. ol!ing boar!

2. -rag an! cope boxes

3. ol!ing san!

4. :arting san!

5. 0aer

6. tri$eoff bar

7. ello&s

8. 0iser an! spr"e pins

9. Bate c"tter

1D. ent ro!

11. -ra& spi$e

12. #ire r"sh


1. an! preparation

2. :lacing the o"l! flas$)!rag+ on the o"l!ing boar!@ o"l!ing platfor

3. :lacing the pattern at the centre of the o"l!ing flas$

4. 0aing the !rag

5. :lacing r"nner an! riser

6. 0aing the cope

7. 0eoval of the pattern r"nner riser

8. Bate c"tting

Proe@-re> Mo-:@ Maing

1. irst a botto boar! is place! either on the ol!ing platfor or on the floor a$ing the s"rface

even.

2. The !rag ol!ing flas$ is $ept "psi!e !o&n on the botto boar! along &ith the !rag part of the

pattern at the centre of the flas$ on the boar!.

3. -ry facing san! is sprin$le! over the boar! an! pattern to provi!e a nonstic$y layer.

4. reshly prepare! ol!ing san! of re("isite ("ality is no& po"re! into the !rag an! on the pattern

to a thic$ness of 3D to 5D .

5. 0est of the !rag flas$ is copletely fille! &ith the bac$"p san! an! "niforly rae! to copact

the san!.

Page 35




6. ,fter the raing is over the excess san! in the flas$ is copletely scrape! "sing a flat bar to the

level of the flas$ e!ges.

7. =o& &ith a vent &ire &hich is a &ire of 1 to 2 !iaeter &ith a pointe! en! vent holes are in

the !rag to the f"ll !epth of the flas$ as &ell as to the pattern to facilitate the reoval of gases

!"ring casting soli!ification. This copletes the preparation of the !rag.

8. =o& finishe! !rag flas$ is rolle! over to the botto boar! exposing the pattern.

9. >sing a slic$ the e!ges of san! aro"n! the pattern is repaire!

1D. The cope flas$ on the top of the !rag is locate! aligning again &ith the help of the pins of the !rag

box.

11. pr"e of the gating syste for a$ing the spr"e passage is locate! at a sall !istance of abo"t 5D

fro the pattern. The spr"e base r"nners an! ingates are also locate! as sho&n risers are

also place!. reshly prepare! facing san! is po"re! aro"n! the pattern.

12. The o"l!ing san! is then po"re! in the cope box. The san! is a!e("ately rae! excess san! is

scrape! an! vent holes are a!e all over in the cope as in the !rag.

13. The spr"e an! the riser are caref"lly &ith!ra&n fro the flas$

14. ?ater the po"ring basin is c"t near the top of the spr"e.

15. The cope is separate! fro the !rag any loose san! on the cope an! !rag interface is blo&n off

&ith the help of the bello&s.

16. =o& the cope an! the !rag pattern halves are &ith!ra&n by "sing the !ra& spi$es an! rapping the

pattern all aro"n! to slightly enlarge the o"l! cavity so that the &alls are not spoile! by the&ith!ra&ing pattern.

17. The r"nners an! gates are to be reove! or to be c"t in the o"l! caref"lly &itho"t spoiling the

o"l!.

18. ,ny excess or loose san! is applie! in the r"nners an! o"l! cavity is blo&n a&ay "sing the

bello&s.

19. =o& the facing paste is applie! all over the o"l! cavity an! the r"nners &hich &o"l! give

the finishe! casting a goo! s"rface finish.

2D. , !ry san! core is prepare! "sing a core box. ,fter s"itable ba$ing it is place! in the o"l!cavity.

21. The cope is place! bac$ on the !rag ta$ing care of the alignent of the t&o by eans of the pins.

##. The o"l! is rea!y for po"ring olten etal. The li("i! etal is allo&e! to cool an! becoe

soli! &hich is the casting !esire!.

Re,-:t The re("ire! o"l! cavity is prepare! "sing the given ingle @soli! :attern.

Page 36




Page 3=




E=P> )1 MO$L% !OR A Sp:it Pattern.

Aim> To prepare a san! ol! "sing the given plitpiece pattern.

Ra? Materia: reD-ire@> o"l!ing san! :arting san! facing san! ba$ing san! pattern botto boar!

o"l!ing boxes.Too:, ReD-ire@>

1. ol!ing boar!

2. -rag an! cope boxes

3. ol!ing san!

4. :arting san!

5. 0aer

6. tri$eoff bar

7. ello&s

8. 0iser an! spr"e pins

9. Bate c"tter

1D. ent ro!

11. -ra& spi$e

12. #ire r"sh


1. an! preparation

2. :lacing the o"l! flas$)!rag+ on the o"l!ing boar!@ o"l!ing platfor

3. :lacing the split pattern at the centre of the o"l!ing flas$

4. 0aing the !rag

5. :lacing the pattern at the centre of the o"l!ing flas$ )%ope box+

6. :lacing r"nner an! riser

7. 0aing the cope

8. 0eoval of the pattern r"nner riser

9. Bate c"tting

Proe@-re> Mo-:@ Maing

1. irst a botto boar! is place! either on the ol!ing platfor or on the floor a$ing the s"rface even.

2. The !rag ol!ing flas$ is $ept "psi!e !o&n on the botto boar! along &ith the !rag part of the

pattern at the centre of the flas$ on the boar!.

3. -ry facing san! is sprin$le! over the boar! an! pattern to provi!e a nonstic$y layer.

4. reshly prepare! ol!ing san! of re("isite ("ality is no& po"re! into the !rag an! on the split

pattern to a thic$ness of 3D to 5D .

5. 0est of the !rag flas$ is copletely fille! &ith the bac$"p san! an! "niforly rae! to copact

the san!.

Page 38




6. ,fter the raing is over the excess san! in the flas$ is copletely scrape! "sing a flat bar to the

level of the flas$ e!ges.

7. =o& &ith a vent &ire &hich is a &ire of 1 to 2 !iaeter &ith a pointe! en! vent holes are in the

!rag to the f"ll !epth of the flas$ as &ell as to the pattern to facilitate the reoval of gases !"ring

casting soli!ification. This copletes the preparation of the !rag.

8. =o& finishe! !rag flas$ is rolle! over to the botto boar! exposing the pattern.

9. >sing a slic$ the e!ges of san! aro"n! the pattern is repaire! an! cope half of the pattern is

place! over the !rag pattern aligning it &ith the help of !o&el pins

1D. The cope flas$ on the top of the !rag is locate! aligning again &ith the help of the pins of the !rag

box.

11. -ry parting san! is sprin$le! all over the !rag s"rface an! on the pattern

12. pr"e of the gating syste for a$ing the spr"e passage is locate! at a sall !istance of abo"t 5D

fro the pattern. The spr"e base r"nners an! ingates are also locate! as sho&n risers are also place!.

reshly prepare! facing san! is po"re! aro"n! the pattern.

13. The o"l!ing san! is then po"re! in the cope box. The san! is a!e("ately rae! excess san! is

scrape! an! vent holes are a!e all over in the cope as in the !rag.

14. The spr"e an! the riser are caref"lly &ith!ra&n fro the flas$

15. ?ater the po"ring basin is c"t near the top of the spr"e.

16. The cope is separate! fro the !rag any loose san! on the cope an! !rag interface is blo&n off &ith

the help of the bello&s.

17. =o& the cope an! the !rag pattern halves are &ith!ra&n by "sing the !ra& spi$es an! rapping the

pattern all aro"n! to slightly enlarge the o"l! cavity so that the &alls are not spoile! by the

&ith!ra&ing pattern.

18. The r"nners an! gates are to be reove! or to be c"t in the o"l! caref"lly &itho"t spoiling the

o"l!.

19. ,ny excess or loose san! is applie! in the r"nners an! o"l! cavity is blo&n a&ay "sing the bello&s.

2D. =o& the facing paste is applie! all over the o"l! cavity an! the r"nners &hich &o"l! give

the finishe! casting a goo! s"rface finish.21. , !ry san! core is prepare! "sing a core box. ,fter s"itable ba$ing it is place! in the o"l! cavity.

22. The cope is place! bac$ on the !rag ta$ing care of the alignent of the t&o by eans of the pins.

Page 39




23. The o"l! is rea!y for po"ring olten etal. The li("i!etal is allo&e! to cool an! becoe soli! &hich is the casting!esire!.

Re,-:t> The re("ire! o"l! cavity is prepare! "sing the given

plit :attern

Se ?1 P'ae rag ar o" *e aern on /ou'oar an ''e +i* /ou' !an

Se -2? #urn rag o@ u!ie o+n an P'ae oe o@over rag o@

Se -3? 'ae oe ar o" *e aern :ri!er:Srue: runner in o!iion an ''e +i* /ou'!an.

Se-4? Fina''$ *e Mou' avi$ i! roue $re/oving *e aern .



Page 40




SHEET METAL 'ORK

1. INTRO%$CTION

heet etal &or$ has its o&n significance in the engineering &or$. any pro!"cts &hich f"lfill the

ho"sehol! nee!s !ecoration &or$ an! vario"s engineering articles are pro!"ce! frosheet etals.

%oon exaples of sheet etal &or$ are hoopers canisters g"ar!s covers pipes hoo!s f"nnels ben!s boxes etc. "ch articles are fo"n! less expensive lighter in &eight an! in soe cases sheet etal

pro!"cts replace the "se of castings or forgings.

#. METALS $SE% IN SHEET METAL 'ORK>

, etal plate of thic$ness less than 4 is consi!ere! as sheet. The siCe of the sheet is specifie! by its

length &i!th an! thic$ness in . n ritish syste the thic$ness of sheet is specifie! by a n"ber

calle! tan!ar! #ire Ba"ge )#B+. The coonly "se! ga"ge n"bers an! the e("ivalent thic$ness in

are given belo&

#B16 17 18 19 2D 22 24 27 3D

)=o.+Thic$ness

1.62 1.42 1.22 1.D2 D.91 D.71 D.56 D.42 D.37)+

The follo&ing etals are generally "se! in sheet etal &or$

i. B:a Iron S7eet

t is the cheapest aong ail. t has a bl"ishblac$ appearance an! is "ncoate! sheet. eing

"ncoate! it corro!es rapi!ly. t is prepare! by rolling to the !esire! thic$ness then anneale! by

pleasing in a f"rnace an! then set asi!e to cool gra!"ally. The "se of this etal is liite! to

articles that are to be painte! or enaele! s"ch as stovepipes tan$s pans etc.

ii. "a:<aniFe@ Iron

t is soft steel coate! &ith olten Cinc. This coating resist r"st iproves appearances iprovessol!erability an! iproves &ater resistance. t is pop"larly $no&n as B.. sheets. ,rticles s"ch as

pans b"c$ets f"rnaces cabinet etc. are a!e fro Bl sheets.

iii.Stain:e,, Stee:

t is an alloy of steel &ith nic$el chroi" an! traces of other etals. t has goo! corrosiveresistance. The cost of stainless steel is very high b"t to"gher than Bl sheets. t is "se! in$itchen&are foo! han!ling e("ipent cheical plants etc.

i<.Copper

t is a re!!ish colore! etal an! is extreely alleable an! !"ctile. %opper sheets have goo!

corrosion resistance as &ell as goo! appearances b"t costs are high as copare! to Bl an!

stainless steel. eca"se of high theral con!"ctivity it is "se! for the ra!iator of a"toobiles

!oestic heating appliances etc.

<. A:-mini-m

,l"ini" cannot be "se! in its p"re for b"t is "se! in alloy for. %oon a!!itions are

copper silicon anganese an! iron. t has any ("alities li$e high ratio of strength to &eight

corrosion resistant ("alities an! ease in fabrication an! &hitish in color. t is "se! in

an"fact"ring of a n"ber of pro!"cts s"ch as refrigerator trays ho"sehol! appliances lighting

fixt"res &in!o& &or$ constr"ction of airplanes an! in any electrical an! transportation

in!"stries.

<i.Tin P:ate,

t is an iron sheet coate! &ith the tin to protect it against r"st. This etal has a very bright silveryappearance an! is "se! principally in a$ing foo! containers cans an! pans.

<ii. Lea@

t is a very soft alleable lo& elting point an! possesses high resistance to aci! corrosion. t ishaving lo& echanical strength so it is "se! to provi!e lining to the highly corrosive aci! tan$s. tis also "se! in ra!iation shiel!ing.

Page 41




. HAN% TOOLS>

or eas"ring ar$ing c"tting an! foring vario"s types of han! tools are "se! in sheet etal &or$. ,list of the is given belo&

. eas"ring tools

,. ar$ing tools. %"tting tools

. oring tools

. <oining tools

I. MEAS$RIN" TOOLS

The follo&ing types of tools are coonly "se! in sheet etal shops toeas"re the !iensions of &or$ pieces

1. teel r"le

2. ernier caliper

3. icroeter

4. heet etal ga"geThe above tools are alrea!y explaine! in the fitting section.

SHEET METAL "A$"E

t is a !isc shape! piece of etal having a n"ber of slots on the o"tsi!e

e!ge as sho&n in fig"re. The slots are of vario"s &i!ths an! each correspon!s

to a certain stan!ar! &ire ga"ge )#B+ n"ber. The ga"ge is place! over the

e!ge of the sheet to

be eas"re! an! a slot is fo"n! that &ill slip over the etal &ith a light fit press"re. tan!ar! tables are referre! to for

conversion of #B n"bers to siCes.

II. MARKIN" TOOLS>

1. Sri0er>t is "se! to scribe or ar$ line on a etal s"rface for a variety of p"rposes. t is a etal&or$erNs pencil

#. Tramme:> These are "se! for !ra&ing large circles an! arcs that are beyon!

the liit of !ivi!ers. t has t&o straight reovable legs tapere! to a nee!le

point o"nte! on separate hol!ers &hich sli!e on steel )or &oo!en+ bar an!

hel! in position by th"b scre&s.

Fig . Sanar +iregauge

Fig . Srier

Fig . #ra//e' Poin!

. P-n7e,> t is "se! in sheet etal &or$ for ar$ing on sheet locating centers. There are t&o types of p"nches.

a+ -ot p"nch an! b+ :ric$ p"nch.

These are alrea!y explaine! in fitting section in !etail.

III C$TTIN" TOOLS>

To c"t the sheet etal as per the pattern !ra&n an! to a$eholes for rivets etc. the follo&ing types of tools are "se!.

, snip is a han! shear "se! to c"t thin sheets of ga"ge siCe

n"ber 2D or above. t &or$s li$e or!inary scissors. There are

several types an! siCes of snips available to c"t along straight

lines or c"rve! lines.

ig"re )a+ sho&s a straight snip having straight bla!es to c"t along straight lines. ig"re )b+ sho&s a bent

Page 42




snip having c"rve! bla!es to c"t along c"rve! lines. These snips are "se! for c"tting thin sheets. Theheavier types are $no&n as bench shear an! bloc$ shear.

Fig. Me*ania' S*earing re!!

I2. !ORMIN" TOOLS>

haping of the sheet etal s"ch as fol!ing ben!ing c"rling etc. are !one by "sing the follo&ing types of foring tools.

1. Stae,>

ta$es are the sheet etal anvils "se! for ben!ing seaing an! foring by "sing ahaer or allet.They &or$ as the s"pporting tool as &ell as the foring tools. They are a!ein !ifferent siCes an! shapes!epen!ing "pon the job re("ireent. %oonly "se! sta$es are

Stae Ho:@er

The sta$e hol!er "se! in sheet etal shop is a rectang"lar bench plate as sho&n in ig"re.

Page 43




Fig. Sake Ho'er

#. HAMMERS>

The sheet etal is shape! by haering or stri$ing &ith allet after $eeping the &or$ on s"itable for

of sta$e. The haers "se! for sheet etal &or$ are )a+ Setting hammer for setting !o&n the e!ge &hile

a$ing !o"ble sea )b+ Raising hammer for foring c"rve! or hollo& shape fro flat piece an! )c+ Riveting hammer for riveting p"rpose. Mallets are soft haers "se! to give soft blo&s &hich &ill not

!aage the sheet at the sae tie &ill shape the. The coonly "se! types of haers an! allets are

sho&n in ig"re.

I2 3OININ" TOOLS>

The tools excl"sively "se! for a$ing an! finishing joints are

a+ /an! grooves b+ 0ivet set c+ ol!ering irons

Han@ groo<er,> /an! groovers are "se! to flatten an! shape joints a!e in sheet

etal. The tool has a groove of re("ire! &i!th an! !epth li$e a !ie. This groover is

place! over the joint )!o"ble he or loc$ sea+ an! haere! fro the top of it to

shape the joint that of the groove as sho&n fig"re.

RI2ET SET>

0ivet get is a!e of tool steel. ,t

the botto of the rivet set there is a

!eep hole an! a c"pshape! hole.Fig. ive!eThe !eep hole is "se! to !ra& a rivet

thro"gh sheet etal an! c"p shape! hole is

"se! to for the finishe! hea! of the rivet ,nother hole on the ai!e of

the set is to release the b"rrs that are p"nche!. -ollies are "se! to bac$"pFig. ive !e an

o''$rivets &hen it is not possible to s"pport the job on a bench.

SOL%ERIN" IRON>

, sol!ering iron consists of a copper bloc$ fixe! on an iron ro! &ith a

Fig. ive !e ano''$



vario"s shapes an! siCes to s"it the "se as sho&n in fig"re. The p"rpose of the

Page 44




heat so"rce for elting an! sprea!ing the sol!er )filler etal+ at the joining area. The sol!ering iron)copper+ is heate! "sing f"rnace blo&er or by electrical resistance.

Fig. So'ering Aron

SHEET METAL 3OINTS>

The line of joint on a sheet e l pieces is calle! sea. The ost coon types of seas are as follo&s

1. Lap ,eam> This is the siplest sea "se! in sheet etal &or$ )ig"re )a++. This consists of one

e!ge lapping over the other an! joint is a!e by sol!ering or riveting.2. "roo<e@ ,eam> , groove! sea is a!e by hoo$ing t&ofol!e! e!ges together an! then off setting the as sho&n in ig"re 5.8)b+. This joint is selfloc$ing an! stronger to soe extent thanlap sea.

3. Sing:e ,eam> This sea is "se! to join a botto portion to a vertical bo!y as sho&n in ig"re )c+.The botto e!ge is hoo$e! over the bent e!ge of the vertical bo!y. This etho! of joint can be"se! for s("are rectang"lar or ro"n! containers.

4. %o-0:e ,eam> This sea is siilar lo single sca &ith the !ifference that the fore! e!ge is bent"p&ar!s against the bo!y as sho&n in ig"re )!+.

5. %o<e9tai: ,eam> This sea is "se! to connect a cylin!rical piece to a flat as sho&n in ig"re )e+.The e!ge of the cylin!rical part to be joine! is slit at short !istance an! is bent so that alternate

pieces coe insi!e an! o"tsi!e of the joint. :eranent joint is obtaine! by sol!ering or riveting.

6. !:ange@ 40-rre@5 0ottom ,eam> This sea is "se! to fasten the botto of a container to its bo!y.

The flange of a cylin!rical job is often calle! a b"rr. The joint consists of a narro& flange &hichay be joine! to insi!e or o"tsi!e of the vessel as sho&n in fig"re )f+.

E@ge !orming

or sheet etal objects strength is given to the e!ge an! the sharpness is eliinate! by fol!ing the e!ge.The coon types of fol!ing "se! in sheet etal &or$ are as follo&s

1. ingle he 2. -o"ble he 3. #ire! e!ge

ig"re sho&s the three types of e!ge fol!ing. , &ire! e!ge consists of an e!ge &rappe! aro"n! a steel

&ire for better strength.

Page 45




Page 46




E=P> )1 RECTAN"$LAR TRAY

AIM> To a$e a rectang"lar Tray as per re("ire! !iensions.

MATERIALS REG$IRE%>

BalvaniCe! ron sheet )15DL11DL26 ga"ge+TOOLS AN% EG$IPMENT REG$IRE%>

1. teel r"le2. lat file

3. criber

4. Try s("are

5. nips

6. -ot p"nch

7. ta$es

8. allet

OPERATIONS TO BE

CARRIE% O$T>

1. :lanning2. ar$ing

3. %"tting

4. en!ing

5. eaing

6. ol!ering

PROCE%$RE>

1. The siCe of the given sheet is chec$e! &ith steel r"le.

2. ar$ the eas"reent an! a$e the !evelopent s"rface s$etch !iagra.

3. The layo"t of the tray is ar$e! on given sheet.4. The layo"t of the tray is c"t by "sing the straight snips.

5. The sheet is bent to the re("ire! shape "sing sta$es an! allet.

6. =o& the bent e!ges are a!e to overlap each other an! st"c$ &ith a allet to get the re("ire! joint.

7. The joint is sol!ere!.

PRECA$TIONS>

1. %are sho"l! be ta$en &hile c"tting &ith snip.

2. %are sho"l! be ta$en &hile ben!ing an! j"ping.

RES$LT>

The rectang"lar tray is !one s"ccess f"lly a!e

Page 4=




E=PT NO> )# RO$N% PIPE

AIM> To a$e a cylin!rical pipe as per re("ire! !iensions.

MATERIALS REG$IRE%>

BalvaniCe! ron sheet )1DDL38L26 ga"ge+

TOOLS AN% EG$IPMENT REG$IRE%>

1. teel r"le2. lat file

3. criber

4. Try s("are

5. nips

6. -ot p"nch

7. ta$es

8. allet

OPERATIONS TO BECARRIE% O$T>

1. :lanning2. ar$ing

3. %"tting

4. en!ing

5. eaing

6. ol!ering

PROCE%$RE>

1. The siCe of the given sheet is chec$e! &ith steel r"le.

2. ar$ the eas"reent an! a$e the !evelopent s"rface s$etch !iagra.

3. The layo"t of the cylin!rical shape pipe is ar$e! on the given sheet.

4. The sheet is bent to the re("ire! shape "sing sta$es an! allet.

5. =o& the e!ges are slightly bent to one is one si!e an! the other is opposite si!e "sing sta$es an!allet.

6. <oin both the en!s &ith in a cylin!rical shape.

PRECA$TIONS>

1. %are "st be ta$en &hile c"tting snips.

2. %are "st be ta$en &hile ben!ing an! joining.

RES$LT>The cylin!rical shape is a!e s"ccessf"lly.

Page 48




'EL%IN"

#el!ing is a process for joining t&o siilar or !issiilar etals by f"sion. t joins !ifferent etals@alloys

&ith or &itho"t the application of press"re an! &ith or &itho"t the "se of filler etal. The f"sion of etal

ta$es place by eans of heat. The heat ay be generate! either fro cob"stion of gases electric arc

electric resistance or by cheical reaction.

#el!ing provi!es a peranent joint b"t it norally affects the etall"rgy of the coponents. t is

therefore "s"ally accopanie! by post &el! heat treatent for ost of the critical coponents. The

&el!ing is &i!ely "se! as a fabrication an! repairing process in in!"stries. oe of the typical

applications of &el!ing incl"!e the fabrication of ships press"re vessels a"toobile bo!ies offshore

platfor bri!ges &el!e! pipes sealing of n"clear f"el an! explosives etc.

ost of the etals an! alloys can be &el!e! by one

type of &el!ing process or the other. /o&ever

soe are easier to &el! than others. To copare

this ease in &el!ing ter P&el!abilityF is often

"se!. The &el!ability ay be !efine! as property of

a etal &hich in!icates the ease &ith &hich it can

be &el!e! &ith other siilar or !issiilar etals.

leents of &el!ing process "se! &ith coon

&el!ing joints s"ch as base etal f"sion Cone &el! face root face root opening toe an! root are !epicte!in ig"re.

E@ge preparation,

or &el!ing the e!ges of joining s"rfaces of etals are prepare! first. -ifferent e!ge preparations ay be"se! for &el!ing b"tt joints &hich are given in ig"re.

'e:@ing ;oint,

oe coon &el!ing joints are sho&n in ig"re. #el!ing joints are of generally of t&o ajor $in!snaely lap joint an! b"tt joint. The ain types are !escribe! as "n!er.

Page 49

#er/ino'og$ o" +e'ing roe!!




1. Lap ?e:@ ;oint

Sing:e9Lap 3oint

This joint a!e by overlapping the e!ges of the plate is

not recoen!e! for ost &or$. The single lap has very

little resistance to ben!ing. t can be "se! satisfactorily for joining t&o cylin!ers that fit insi!e one another.

%o-0:e9Lap 3oint

This is stronger than the singlelap joint b"t has the!isa!vantage that it re("ires t&ice as "ch &el!ing.

Tee !i::et 'e:@

This type of joint altho"gh &i!ely "se! sho"l! not be eploye! if an alternative !esign is possible.

#. B-tt ?e:@ ;oint

a. Sing:e92ee B-tt 'e:@

t is "se! for plates "p to 15.8 thic$. The angle of the vee !epen!s "pon the techni("e being "se!the plates being space! approxiately 3.2 .

0. %o-0:e92ee B-tt 'e:@

t is "se! for plates over 13 thic$ &hen the &el!ing can be perfore! on both si!es of the plate.The top vee angle is either 6DE or 8DE &hile the botto angle is 8DE !epen!ing on the techni("e

being "se!.

'e:@ing Po,ition,

,s sho&n in ig. 17.4 there are fo"r types of &el!ing positions &hich are given as

a. lat or !o&n han! position

b. /oriContal position

c. ertical position

!. ;verhea! position

!:at or %o?n97an@ 'e:@ing Po,ition

The flat position or !o&n han! position is one in &hich the &el!ing is perfore! fro the "pper si!e of the joint an! the face of the &el! is approxiately horiContal.

HoriFonta: 'e:@ing Po,ition

n horiContal position the plane of the &or$piece is vertical an! the !eposite! &el! hea! is horiContal.This position of &el!ing is ost coonly "se! in &el!ing vessels an! reservoirs.

2ertia: 'e:@ing Po,ition

n vertical position the plane of the &or$piece is vertical an! the &el! is !eposite! "pon a verticals"rface. t is !iffic"lt to pro!"ce satisfactory &el!s in this position !"e to the effect of the force of gravityon the olten etal.

O<er7ea@ 'e:@ing Po,ition

Page 50




#el!ing cables are re("ire! for con!"ction of c"rrent fro the po&er so"rce thro"gh the electro!ehol!er the arc the &or$ piece an! bac$ to the &el!ing po&er so"rce. These are ins"late! copper or al"in" cables.

. E:etro@e 7o:@er

lectro!e hol!er is "se! for hol!ing the electro!e an"ally an!con!"cting c"rrent to it. These are "s"ally atche! to the siCe of thelea! &hich in t"rn atche! to the aperage o"tp"t of the arc &el!er.

lectro!e hol!ers are available in siCes that range fro 15D to 5DD Fig. 'eroe Ho'er ,ps.

&. 'e:@ing E:etro@e,

,n electro!e is a piece of &ire or a ro! of a etal or alloy &ith or

&itho"t coatings. ,n arc is set "p bet&een electro!e an! &or$piece.

#el!ing electro!es are classifie! into follo&ing types

)i+ %ons"able lectro!es)a+ are lectro!es

)b+ %oate! lectro!es

)ii+ =oncons"able lectro!es

)a+ %arbon or Braphite lectro!es

)b+ T"ngsten lectro!es

Fig. Par! o" a e'eroe

%ons"able electro!e is a!e of !ifferent etals an! their alloys. The en! of this electro!e starts elting &hen arc

is str"c$ bet&een the electro!e an! &or$piece. Th"s cons"able electro!e itself acts as a filler etal. are

electro!es consist of a etal or alloy &ire &itho"t any fl"x coating on the. %oate! electro!es have fl"x coating

&hich starts elting as soon as an electric arc is str"c$. This coating on elting perfors any f"nctions li$e

prevention of joint fro atospheric containation arc stabiliCers etc.

=oncons"able electro!es are a!e "p of high elting point aterials li$e carbon p"re t"ngsten or alloy

t"ngsten etc. These electro!es !o not elt a&ay !"ring &el!ing. "t practically the electro!e length goes on

!ecreasing &ith the passage of tie beca"se of oxi!ation an! vaporiCation of the electro!e aterial !"ring

&el!ing. The aterials of noncons"able electro!es are "s"ally copper coate! carbon or graphite p"re t"ngsten

thoriate! or Circoniate! t"ngsten.

(. Han@ Sreen

/an! screen "se! for protection of eyes an! s"pervision of &el! bea!.

6. C7ipping 7ammer

%hipping /aer is "se! to reove the slag by stri$ing.

+. 'ire 0r-,7

#ire br"sh is "se! to clean the s"rface to be &el!.

52




Fig. ar* ,'a/ Fig. ,*iing Ha//erFig. (ire&ru!*

. Proteti<e :ot7ing

;perator &ears the protective clothing s"ch as apron to $eep a&ay the expos"re of !irect heat to the bo!y.

Sa/et Reommen@ation, /or ARC 'e:@ing

The beginner in the fiel! of arc &el!ing "st go thro"gh an! becoe failiar &ith these general safetyrecoen!ations &hich are given as "n!er.

1. The bo!y or the frae of the &el!ing achine shall be efficiently earthe!. :ipe lines containing

gases or inflaable li("i!s or con!"its carrying electrical con!"ctors shall not be "se! for a

gro"n! ret"rn circ"it ,ll earth connections shall be echanically strong an! electrically a!e("ate

for the re("ire! c"rrent.

2. #el!ing arc in a!!ition to being very is a so"rce of infrare! an! "ltraviolet light alsoHconse("ently the operator "st "se either helet or a han!shiel! fitte! &ith a special filter glass to

protect eyes

3. xcess "ltraviolet light can ca"se an effect siilar to s"nb"rn on the s$in of the &el!er

4. The &el!erFs bo!y an! clothing are protecte! fro ra!iation an! b"rns ca"se! by spar$s an! flyingglob"les of olten etal &ith the help of the follo&ing

5. Bloves protect the han!s of a &el!er.

6. ?eather or asbestos apron is very "sef"l to protect &el!erFs clothes an! his tr"n$ an! thighs &hileseate! he is !oing &el!ing.

7. or overhea! &el!ing soe for of protection for the hea! is re("ire!

8. ?eather s$"ll cap or pea$e! cap &ill !o the nee!f"l.

9. ?eather jac$ets an! 1ather leggings are also available as clothes for bo!y protection.

1D. #el!ing e("ipent shall be inspecte! perio!ically an! aintaine! in safe &or$ing or!er at all ties.

11. ,rc &el!ing achines sho"l! be of s"itable ("ality.

12. ,ll parts of &el!ing set shall be s"itably enclose! an! protecte! to eet the "s"al service con!itions.

53




E=PT NO> )1 B$TT 3OINT

Aim> To a$e a "tt joint "sing the given t&o . pieces by arc &el!ing.

Materia: ReD-ire@>

il! steel plate of siCe 1DDM5DM5 J 2 =oFs

'e:@ing E:etro@e, . electro!es 3.1 M35D

'e:@ing ED-ipment ,ir coole! transforer

oltage8D to 6DD 3 phase s"pply aps "p to 35D

Too:, an@ Ae,,orie, reD-ire@>

1. 0o"gh an! sooth files.2. :rotractor

3. ,rc &el!ing achine )transforer type+

4. il! steel electro!e an! electro!e hol!er5. Bro"n! clap

6. Tongs

7. ace shiel!

8. ,pron

9. %hipping haer.


1. ar$ing

2. %"tting

3. !ge preparation )0eoval of r"st scale etc.+ by filling4. Try s("are leveling

5. Tac$ing

6. #el!ing7. %ooling

8. %hipping

9. %leaning

Proe@-re>

1. The given . pieces are thoro"ghly cleane! of r"st an! scale.

2. ;ne e!ge of each piece is believe! to an angle of 3DD leaving nearly Q

th of the flat thic$ness

at one en!.

3. The t&o pieces are positione! on the &el!ing table s"ch that they are separate! slightly for better penetration of the &el!.

4. The electro!e is fitte! in the electro!e hol!er an! the &el!ing c"rrent is ser to be a proper val"e.5. The gro"n! clap is fastene! to the &el!ing table.

6. #earing the apron an! "sing the face shiel! the arc is str"c$ an! hol!ing the t&o piecestogetherH first r"n of the &el! is !one to fill the root gap.

7. econ! r"n of the &el! is !one &ith proper &eaving an! &ith "nifor oveent. -"ring the process of &el!ing the electro!e is $ept at 15

D to 25

D fro vertical an! in the !irection of

&el!ing.8. The scale foration on the &el!s is reove! by "sing the chipping haer.

9. illing is !one to reove any spanner aro"n! the &el!.

54




%RA'IN">

Re,-:t>

The single b"tt joint is th"s a!e "sing the tools an! e("ipent as entione! above.

55




Re,-:t>

The ?ap joint is th"s a!e "sing the tools an! e("ipent as entione!

5=




E=PT NO> ) CORNER 3OINT

Aim> To a$e a corner joint "sing the given t&o . pieces an! by arc &el!ing.

Materia: S-pp:ie@>

il! steel plate of siCe 1DDM5DM5 J 2 =oFs

'e:@ing E:etro@e, . electro!es 3.1 M35D

'e:@ing ED-ipment ,ir coole! transforer

oltage8D to 6DD 3 phase s"pply aps "p to 35D

Too:, an@ Ae,,orie, reD-ire@>

1. 0o"gh an! sooth files.

2. :rotractor

3. ,rc &el!ing achine )transforer type+4. il! steel electro!e an! electro!e hol!er

5. Bro"n! clap6. Tongs

7. ace shiel!8. ,pron

9. %hipping haer.


1. ar$ing

2. %"tting

3. !ge preparation )0eoval of r"st scale etc.+ by filling

4. Try s("are leveling5. Tac$ing

6. #el!ing

7. %ooling

8. %hipping

9. %leaning

Proe@-re>

1. The given . pieces are thoro"ghly cleane! of r"st an! scale.

2. The t&o pieces are positione! on the &el!ing table s"ch that the ? shape is fore!. The tongsare a!e "se of for the p"rpose.3. The electro!e is fitte! in the electro!e hol!er an! the &el!ing c"rrent is ser to be a proper val"e.

4. The gro"n! clap is fastene! to the &el!ing table.

5. #earing the apron an! "sing the face shiel! the arc is str"c$ an! the &or$ pieces are tac$&el!e! at both the en!s an! at the centre of the joint.

6. The alignent of the corner joint is chec$e! an! the tac$&el!e! pieces are re("ire!.

7. The scale foration on the &el!s is reove! by "sing the chipping haer.

8. illing is !one to reove any spanner aro"n! the &el!.

58




/;> #0=B

INTRO%$CTION>

:o&er is s"pplie! to !oesticate installations thro"gh a phase an! ne"tral foring a single phase ,%

23D v to &ire syste. or in!ivi!"al establishent po&er is s"pplie! thro"gh three phase t&o &ire

syste. To give 44D the ne"tral is earthe! at to the !oestic "tilitiesH po&er is fe! to $ilo &att eter an! then to !istrib"tes po&er along several circ"its. t also protects these circ"its fro over loa! by

safety !evices li$e f"ses or circ"it brea$ers.

ELEMENTS O! HO$SE 'IRIN">

1. "ses an! circ"it brea$ers

2. lectric s&itch

3. :l"g

4. oc$et o"t let

5. ?ap hol!er

6. ain s&itch7. ncan!esant tight

#0=B T/;- , circ"it is path along &hich the electric c"rrent flo&s fro negative si!e of po&er so"rce to positive si!e.

%;;= /;> #0=B 0:,0

1. 0eplacing a f"se

2. 0es"lting a circ"it bea$er

3. 0es"lting a s&itch or an o"t let

4. 0epair of ho"se hol! appliances

PRECA$TIONS>

1. ns"re that the ins"lation of &ire reaches "p to accessory

2. -o not over tighten the scre&

3. ns"re that the base &ire is not to"ching any part of accessory.

R$LERS O! 'IRIN">

1. very fitting or appliances "st also be controlle! by a s&itch.

60




2. The s&itch sho"l! be on the line con!"ctor

3. very s"bcirc"it "st have a separate f"se.

,ll the etals covering fraes etc. sho"l! be earthe!.

Inan@e,ent Lig7t>

n can!escent eans Pglo&ingat &hite hotF ., lap act"ally &or$ sli$e aheating

eleentexceptthat it gives of flight by becoing &hiteh ot. ig"re3.9. sho&s the part s of a b"lb. The

ao"nt of po&erit cons"e sisstape! on the b"lb. The higher the &attage brighterthe light.The b"lbs

have filaents a!e of t"ngsten. /o&ever special b"lbs are available &ith insi!e coating an! fille!

&ith gas.

'ire, an@ 'ire SiFe,>

, &ire is !efine! asa bare or an ins"late! con!"ctor consisting of one or several stran!s. ,nins"late! &ire consists of a con!"ctor &ith ins"lating aterial a!e of v"lcaniCe! n!ia r"bber )0+ or

polyvinylchlori!e ):%+. The &ire ay consist o f one or several t&iste! stran!s. , "lti corecon!"ctor consists of several cores ins"late! fro one another an! enclose! in a coon sheathing

)fig.3.1D+.

#ires iCe sare specifie! by !iaeter of the &ire "sing a stan! ar! &ire ga"ge )#B+ &hichalso gives an i!eao f the c"rrent carrying capacity. Thespecification consist so fb ot htheno. ;f stran!san! the !iaeter of each &ire in it. orexaple the specification (i)silk wire14/3 indicates14strands of 3S!" each and

(ii )3/1# $%& indicates 3 strands of 1#S!" each.

61




E=PT NO> 1 ONE LAMP CONTROLLE% BY ONE S'ITCH

%ATE>

AIM> To control one lap by a one s&itch &ith provision for pl"g soc$et &ith s&itch control.

MATERIALS REG$IRE% 'ITH %IMENSIONS>

1. 1@18Opvc &ire of s"fficient length2. ;ne &ay s&itch J 2 no.

3. T&opin pl"g soc$et1no.

4. "lb1no.

5. "lb hol!er1no.

TOOLS AN% EG$IPMENT $SE%>

1. 6Oc"tting pliers

2. 1.5 ball peen haer.

3. #ire stripper

4. Tester

5. 6Oscre& !rivers6. /ac$ sa&

7. 12 han! !rilling achine.

OPERATIONS TO BE CARRIE% O$T>

1. itting the &ires

2. %onnection of the b"lb hol!er

3. %onnection of pl"g soc$et

4. %onnection of s&itch

5. %irc"it connections

6. :o&er fro ains

7. ;peration the b"lb

8. Testing the pl"g soc$et.

PROCE%$RE>

1. The o"tline &iring !iagra ar$e! on the &oo!en boar! an! clips are naile! to the boar!

follo&ing the !iagra six &ire pieces are ta$en an! ins"lation is reove! at the en!s by "sing

&ire stripper.

2. , phase &ire is connecte! to one point s&itch s1 an! s2.

3. The lo&er points of s&itches s1an!s2 are connecte! to one point of b"lb hol!er an! one point of pl"g soc$et respectively.

4. T&o ne"tral &ires are ta$en an! one in connecte! to the reaining point of the b"lb hol!er.

5. The other is connecte! to the reaining points of pl"g soc$et.

6. ,fter chec$ing the proper circ"it connections the po&er s"pply is given.

7. =o& the b"lb is rea!y to glo& bright an! the pl"g soc$et is also rea!y &ith control.

PRECA$TIONS>

1. ,ll the &ire connections of the s&itches b"lb hol!er an! soc$ets are tight.

2. Too any loa! connections fr4o a single j"nction are avoi!e!.

RES$LT>

#hen the &ires are connecte! the b"lb glo&s.

62




E=PT NO># T'O LAMPS CONTROLLE% BY SIN"LE S'ITCH

%ATE>

AIM to control t&o laps by a one s&itch &ith provision for pl"g soc$et &ith s&itch control.

MATERIALS REG$IRE% 'ITH %IMENSIONS>

1. 1@18Opvc &ire of s"fficient length

2. ;ne &ay s&itch J 2 no.

3. T&opin pl"g soc$et1no.

4. "lb1no.

5. "lb hol!er1no.

TOOLS AN% EG$IPMENT $SE%>

1. 6Oc"tting pliers

2. 1.5 ball peen haer.

3. #ire stripper

4. Tester

5. 6Oscre& !rivers6. /ac$ sa&

7. 12 han! !rilling achine.

OPERATIONS TO BE CARRIE%O$T>

1. itting the &ires

2. %onnection of the b"lb hol!er

3. %onnection of pl"g soc$et

4. %onnection of s&itch

5. %irc"it connections

6. :o&er fro ains

7. ;peration the b"lb

8. Testing the pl"g soc$et.

PROCE%$RE>

1. The o"tline &iring !iagra ar$e! on the &oo!en boar! an! clips are naile! to the boar!

follo&ing the !iagra six &ire pieces are ta$en an! ins"lation is reove! at the en!s by "sing

&ire stripper.

2. , phase &ire is connecte! to one point s&itch s1 an! s2.

3. The lo&er points of s&itches s1an!s2 are connecte! to one point of b"lb hol!er an! one point of pl"g soc$et respectively.

4. T&o ne"tral &ires are ta$en an! one in connecte! to the reaining point of the b"lb hol!er.

5. The other is connecte! to the reaining points of pl"g soc$et.6. ,fter chec$ing the proper circ"it connections the po&er s"pply is given.

7. =o& the b"lb is rea!y to glo& bright an! the pl"g soc$et is also rea!y &ith control.

PRECA$TIONS>

1. ,ll the &ire connections of the s&itches b"lb hol!er an! soc$ets be tight.

2. Too any loa! connections fr4o a single j"nction are avoi!e!.

RES$LT>

1. n series connection if one b"lb !oes not glo& the b"lb also !oes not glo&s.

2. n parallel connection if one b"lb !oes not glo& the other b"lb blo&s.

63




E=PT NO> STAIR CASE 'IRIN"

%ATE>

Aim To !o stair case &iring )i.e. control of one lap by t&o s&itches fixe! att&o !ifferent places+.

Materia:, reD-ire@

:% &ire of s"fficient length 5noT&o&ays&itches b"lb hol!ers ceiling rose an! b"lb.

Too:, an@ eD-ipment -,e@

1. 6FF c"tting pliers

2. 6FFscre&!rivers

3. #ire stripper

4. Tester

.Operation, to 0e arrie@ o-t

1. itting the &ires2. %onnection of the b"lb hol!er

3. %onnection of s&itches

4. %irc"itconnection

5. :o&er fro ains6. ;perating the lap

Proe@-re

, phase &ire is ta$en an! its one en! is connecte! to the i!!le point of t&o J &ays&itch 1. #hile the other en! is connecte! to the phase point of ain s"pply. ,nother phase&ire )secon! &ire+ is ta$en an! "se! for connecting the lo&er points of the t&o s&itches1H2.The thir! phase &ire piece is ta$en an! is connecte! bet&een the i!!le point of 2 an!

one of the points o f the b"lb hol!er ., ne"tral &ire piece is ta$en an! its one en! isconnecte! to the reaining points of b"lb hol!ers &hile the other en! is connecte! to ains"pply. =o& the glo&ing of the b"lb is controlle! by t&o &ay s&itches.

Prea-tion,

1. ,ll &ire connections to the s&itches an! b"lb hol!ers sho"l! be right.

2. ,l&ays re! &ire sho"l! be "se! for phase an! blac$ for ne"tral.

3. Too any loa! connections fro a single j"nctions are avoi!e!

4. &itch sho"l! be connecte! in phase only.

Re,-:t an@ on:-,ion

tair case &iring )i.e. control of one lap by t&o s&itches fixe! at t&o !ifferent

places+ is !one.

.=o. 1 2 ?ap

1 >p >p right2 >p -o&n ;ff

3 -o&n >p ;ff 4 -o&n -o&n right

E=PT NO> & CONTROLLIN" T'O LAMPS BY T'O IN%EPEN%ENT S'ITCHES%ATE>

64




Aim To control t&o laps by t&o in!epen!ent s&itches locate! at t&o !ifferent places.

Materia:, reD-ire@1@18FF:% &ire of s"fficient length 5no t&o &ay s&itches b"lb hol!ers ceilingrose an! b"lbs.


1. 6FF c"tting pliers

2. 6FFscre&!rivers

3. 1.5 lb ballpeen haer

4. /ac$sa&

5. #ire stripper

6. 12han!!rillingachine

7. Tester. .Operation, to 0e arrie@ o-t

1. itting the &ires

2. %onnection of the b"lb hol!er3. %onnection of s&itches4. %irc"itconnection

5. :o&er fro ains6. ;perating the lap

Proe@-re

ive phase &ire pieces are ta$en an! ins"lation is reove! at the en!s by &ire stripper.The first phase &ire is connecte! by secon!s phase &ire. The i!!le point of s&itches2 isconnecte! to one point of b"lb hol!er R2O. y "sing another phase &ire the reaining pointo f the b"lbhol!erR1O. ,t the sae point of b"lbR1O a phase &ire connecte! to the "pper

point of s&itchR1O. T&o ne"tral &ire pieces are ta$en an! connecte! to the reaining pointof b"lbhol!erR1O. ;ne of it is connecte! to the ain s"pply. ,fter chec$ing the proper circ"it connects the po&er s"pply is given to s&itches. =o& the b"lbs are rea!y to sho&

bright an! !i.

Prea-tion,

1. ,ll &ire connections to the s&itches an! b"lb hol!ers sho"l! be right.


3. Too any loa! connections fro a single j"nctions are avoi!e!

4. &itch sho"l! be connecte! in phase only.

Re,-:t

%ontrolling of t&o laps by t&o in!epen!ent s&itches locate! at t&o !ifferent places is !one.

. =o 1 2 ?1 ?2

1 >: -;#= 701B/T ;

2 >: >: 701B/T 701B/T

3 -;#= >: ; ;

4 -;#= -;#= - -

E=PT NO> ( !L$ORESCENT LAMP 'IRIN" %ATE>

Aim To prepare the Rl"orescent ?apO.

65




Materia:, reD-ire@

1@18FF:% &ire of s"fficient length 5no one&ays&itch1 starter1 cho$e1 fl"orescent laphol!ers &ith frae.


6FF c"tting pliers 6FFscre&!rivers 1.5 lb ballpeen haer /ac$sa& #ire stripper 12 han!!rilling achine Tester

Operation, to 0e arrie@ o-t

itting the &ires

%onnection of the fl"orescent lap

%onnection to cho$e

%onnection of s&itches

%irc"itconnection

:o&er fro ains

;perating the lap

Proe@-re

6FF:% &ire pieces are ta$en an! ins"lation is reove! at the en!s by "sing &ire stripper. , phase&ire is connecte! to one point on the s&itch. The other point of the s&itch is connecte! to %ho$e.The other point of the %ho$e is connecte! to one point of the starter an! the other point of l aphol!er1. The other point of the lap hol!er1 is connecte! to one point of the tarter. , ne"tral&ire pieces ta$en an! connecte! to one point of the laphol!er2. The other point of the laphol!er2 is connecte! to 0eaining point of the tarter. ,fter chec$ing proper circ"it connectionsthe po&er s"pply is given. =o& the lap is rea!y to glo&.

Prea-tion,

1. ,ll &ire connections to the s&itches an! b"lb hol!ers sho"l! be tight.


3. &itch sho"l! be connecte! in phase only.4. The s&itches "st be in off position before giving po&er s"pply

Re,-:t ;perating the fl"orescent lap is !one.

E=PT NO> 6 "O%O'N 'IRIN %ATE>

Aim To prepare a Bo!o&n &iring circ"it &ith :% con!"it &iring syste.

Materia:, reD-ire@

:%&ireofs"fficientlength5no T&o&ay s&itches b"lb hol!ers ceiling rose an! b"lb

66




PL$MBIN"

P:-m0ing is a s$ille! tra!e of &or$ing &ith pipes or t"bes an! pl"bing fixt"res. The process

is ainly "se! for the s"pply of !rin$ing &ater an! the !rainage of &aste &ater soeties ixe! &ith

&aste floating aterials in a living or &or$ing place. , pl"ber is soeone &ho installs or repairs

piping systes pl"bing fixt"res an! e("ipent s"ch as valves &ashbasins &ater heaters &ater closests etc. Th"s it "s"ally refers to a syste of pipes an! fixt"res installe! in a b"il!ing for the

!istrib"tion of &ater an! the reoval of &aterborne &astes.

The latin &or! pl"b" eans etal lea! pipe is the origin for !eveloping the ter

pl"bing. :l"bing process &as originate! !"ring the ancient civiliCations s"ch as the gree$ 0oan

:ersian n!ian an! %hinese civiliCations as they !evelope! p"blic baths an! nee!e! to provi!e potable

&ater an! !rainage of &astes carrie! by &ater.

PIPES AN% THEIR 3OINTS>

:ipes are an"fact"re! by "sing !ifferent types of aterials li$e steel cast iron galvaniCe!

iron brass copper al"in" lea! plastic concrete asbestos etc. They are "s"ally classifie!

accor!ing to the aterial. They are also gro"pe! as cast &el!e! sealess extr"!e! etc. or conveying

large ("antity of &ater cast iron steel or concrete pipes having large !iaeter are "s"ally "se!.

BalvaniCe! iron pipes )B pipes+ are pop"lar for e!i" an! lo& press"re &ater s"pply lines.

:lastic pipes are preferre! for ho"sehol! "ses at lo& press"re. :ipes are generally specifie! by

their inner !iaeter )=oinal !iaeter specifie! in inches+. /ence the pipe fitting siCe is also base! on

this !iension. "t for plastic pipes this r"le is not strictly follo&e! beca"se threa!ing is not "s"ally

re("ire! for the. or engineering "ses along &ith the noinal !iaeter the pipe thic$ness is also

specifie! as light e!i" or heavy.

Tpe, o/ pipe ;oint,>

,ccor!ing to the pipe aterial siCe an! application !ifferent etho!s are "se! to join pipes. The ostcoon types of pipe joints are

1. cre&e! pipe joint J or B :ipes

2. #el!e! pipe joint J for steel copper al"in" an! lea! pipes

3. lange! pipe joint J for cast iron an! steel pipes

4. ol!ere! pipe joint J for brass an! copper t"bes

5. Bl"e! or ceente! pipe joint J for :% pipes

:ipes a!e of iron )B :ipes+ an! brass of sall an! e!i" !iaeters )1D to 1DD + are "s"ally

joine! by scre&ing the pipe specials &ith internal or external threa!s. #el!ing is "se! to a$e

peranent joint of e!i" an! large !iaeter steel pipes. lange! pipe joints are coon in e!i"

an! large !iaeter pipes of cast iron an! steel along &ith r"bber@%, )%opresse! asbestos fibre+

gas$ets. The flange! are scre&e! to the pipe for saller !iaeter b"t a!e integral for large !iaeters.

:ipes of copper an! brass are "s"ally joine! by sol!ering.

:% )poly inyl %hlori!e+ pipe is the ost pop"lar choice in plastic gro"p. t is rigi! an! "ses threa!

an! solvent &el! )gl"e+ connections. t also can be heat f"se!. :% pipes are available in vario"s

press"re ratings for &ater s"pply an! is a very choice for lan!scape irrigation. The reasons for the

pop"larity are the econoy no corrosion an! easiness to &or$. %:% is a !ifferent type of plastic

&hich has an extra chlorine ato in the copo"n! can be "se! for the hot &ater s"pply an! in in!"stry.

To join plastic pipes gl"ing or ceenting etho! is "se!. olvent ceent is the gl"ing aterial an! it

partially elts the s"rface of the plastic pipe to a$e the joint. ,s the gl"e evaporates &ithin t&oin"tes a strong joint is obtaine!.

68




cre&e! pipe fittings )pipe specials+ are reovable or teporary pipe connections &hich peritnecessary !isantling or reassebly for the p"rpose of installation aintenance cleaning repair etc.The f"nctions of pipe fittings can be broa!ly classifie! as

1. To join t&o or ore pipe lines together

2. To effect change in !iaeter or !irection

3. To close the en! of a pipe line

The ost coon types of scre&e! pipe fittings "se! in galvaniCe! iron )B+ pipe lines an! plastic):%+ pipe lines are sho&n in ig"re 1 ) to 17+. , brief !escription of these fittings is given belo&

1. Co-p:er 4o-p:ing5> T&o pipe lines of e("al !iaeter an! in axial alignent can be joine! by a co"pler )co"pling+. t is a short sleeve &ith internal threa!.

2. Re@-er o-p:er )0e!"cer co"pling+ This is a co"pler to join t&o pipe lines of !ifferent !iaeters inaxial alignent.

3. *)) E:0o?> This is a pipe special "se! or effecting abr"pt change in !irection thro"gh 9DE. nternal

threa!s are provi!e! on both en!s. ,n elbo& brings t&ice the hea! loss than a ben!.

4. *)

)

Re@-er e:0o?> This is an elbo& &ith o"tlet !iaeter less than that of inlet !iaeter t is "se! to join t&o pipe lines having !ifferent !iaeters an! eeting at right angle.

5.Ben@> This is a pipe special "se! to effect gra!"al change in !irection )"s"ally 9DE+.The t&o en!s of the ben! are externally threa!e!.

6. Ret-rn 7an@> This ben! is "se! to ret"rn the !irection of pipe line thro"gh 18DE.The en!s are internallythrea!e! for fitting the pipe lines.

1. Tee> This pipe special is "se! to a$e a branch connection of sae !iaeter to the ain pipe line atright angle. , Tee is internally threa!e! an! it connects three en!s of pipes.

8. Re@-er Tee> This is a pipe special siilar to Tee "se! to ta$e a branch connection of re!"ce! !iaeter fro the ain pipe line.

9 Cro,,> This pipe special is "se! to ta$e t&o branch connections at right angles to the ain pipe line.The threa!s are provi!e! internally

1D. C:o,e nipp:e> , nipple is a short straight piece of pipe &ith external threa! on both en!s. , close nippleis the shortest one of this category &ith external threa! for the f"ll length. They are "se! to join t&ointernally threa!e! pipe specials an! valves.

11. S7ort nipp:e> , short nipple has the sae shape an! f"nction of a close nipple b"t it has a short"nthrea!e! portion at the i!!le of its length for gripping.

12. S7ort nipp:e ?it7 7exagona: grip> This nipple has an a!!itional hexagonal n"t shape at the i!!le portion for easy scre&ing &ith spanner. t is siilar to an or!inary short nipple except that !ifference.

13. Ho,e nipp:e> , hose nipple is "se! to connect a hose )flexible pipe"s"ally plastic or r"bber+ to a pipeline. ;ne en! of the hosenipple has a steppe! taper to fit the hose &hile other en! has threa!. ,hexagonal n"t shape is given to the i!!le portion for gripping &ith a spanner.

14. Ma:e p:-g> , ale pl"g is "se! to close an internally threa!e! en! of a pipe line or pipe special. t hasexternal threa! an! a grip of s("are shape at the en!.

15. !ema:e p:-g 4ap5> , feale pl"g is "se! to close an externally threa! en! of a pipe or pipe special. thas internal threa! an! a grip of s("are shape at the en!.

16. Sre?e@ -nion> consists of three pieces as sho&n in the !ra&ing. The t&o en! pieces have internal

threa!s at their en!s &hich are connecte! to the pipe en!s. The central hexagonal )or octagonal+ piece

)"nion n"t+ has internal threa! at one en! an! a collar at the other en!. ,fter the en! pieces are scre&e!

on to the pipes the central piece )"nion n"t+ is tightene! to !ra& the en! pieces together to get a &ater

tight joint.

17. !:ange> This is a !isc type pipe special having threa!e! hole at the centre for scre&ing to the externally

threa!e! en! of a pipe line. t &ill have holes aro"n! the central hole at e("al ang"lar spacing )3 4 6f

or 8 =os.+ for joining to another siilar flange or flat s"rface "sing bolt or st"!. xaple for the "se of

vario"s pipe fittings in pipe line is given in ig"re 9.2

69




ig"re 1 ario"s pipe joints.

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ig"re 2 ,pplication of vario"s joints in the pipe fittings

2a:<e, an@ Meter,

alves are "se! in piping systes to control or stop the flo& of li("i! or gas. The ost coon typesof valves "se! in lo& press"re &ater pipe line are

1. #ater tap

2. #ater coc$

3. Blobe valve

4. Bate valve

5. all valve

6. =onret"rn valve

7. oot valve

'ater tap

To collect &ater fro lo& press"re pipe line &ater tap )scre&

!o&n valve+ is coonly "se!. ig"re gives the cross section of

the tap. ts leather or r"bber face! valve !isc is lifte! or lo&ere!

by rotating the spin!le. rass or g"netal is the aterial "se!

for the valve bo!y an! the siCe is specifie! by the pipe to &hich

it is fitte! "s"ally ranging fro 1D to 25 .

'ater o

This is the siplest an! sallest for of a valve in &hich a

conical pl"g calle! coc$ is inserte! into a conical hole having a atching taper. , rectang"lar hole is provi!e! at the centre across the conical potion so that in one position it perits flo& of &ater as sho&nin ig"re. , half t"rn of the han!le &ill bring the soli! portion of

the coc$ to the &ater &ays preventing the flo&. %oc$s are "se! for lo& rate of &ater flo&N or for tapping press"re line to a anoeter etc.

":o0e <a:<e

Blobe valves are "se! as control valves in fl"i! )gas an! li("i!+

pipe lines. ig"re sho&s the siplest an! sallest type of globe

valve "se! in &ater pipe lines. asically the valve is a variable

opening flo& !evice. The !esign of a globe valve also creates a

slight retar!ation to the flo& beca"se the fl"i! is force! to a$e a

!o"ble t"rn an! passes thro"gh the opening at 9DE to the axis of the pipe. The valve pl"g is raise! orlo&ere! to stop or reg"late the flo& thro"gh a circ"lar opening. , globe valve can be i!entifie! by the

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spherical bo!y an! the arro& ar$ for the !irection of flo&. These valves are "se! in &ater pipe linesfro 12 to 1DD or even larger !iaeter for the flo& control p"rpose.

"ate <a:<e>, gate valve is onoff type valve. t allo&s a straightline oveent of fl"i! an! offer very

little resistance to the flo& in f"lly opene! position. The central !isc oves copletely o"t of the passage an! leaves a f"ll opening. ig"re sho&s a siple type of gate valve partially opene! in position.

These valves are very &i!ely "se! in &ater pipe lines of !iaeter

ranging fro 12 to higher val"es. , gate valve can be i!entifie! by its sli bo!y. t is to be note! that there &ill be no arro& ar$ or the bo!y of valve beca"se it can be "se! in both &ays

!oot <a:<e> oot valve is a $in! of nonret"rn valve "se! in

centrif"gal p"ps. t is fitte! at the botto ost en! of the s"ction

pipe )oot+ to stop flo& in the !o&n&ar! !irection for priing

p"rpose. The strainer restricts the entry of floating aterials to the

pipe line. ig"re gives the !etails of the foot valve. The aterial "se!ay be cast iron brass or :%.

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PO'ER TOOLS

INTRO%$CTION>

:o&er tool is a po&ere! by an electric otor a copresse! air otor or a gasoline engine.

:o&er tools are classifie! as either stationary or portable &here portable eans han!hel!. They are"se! in in!"stry in constr"ction an! aro"n! the ho"se for c"tting shapping !rilling san!ing painting

grin!ing an! polishing.

tationary po&er tools for etal&or$ing are "s"ally calle! achine tools.

The lathe is the ol!est po&er tool being $no&n to the ancient gyptians. arly in!"strialrevol"tionera factories ha! batteries of po&er tools !riven by belts fro overhea! shafts. The prie

po&er so"rce &as a &ater &heel or a stea engine.

tationary po&er tools are priCe! not only for their spee! b"t for their acc"racy. , table sa& not

only c"ts faster than a han! sa& b"t the c"ts are soother straighter an! ore s("are than even the

ost s$ille! an can co &ith a han!sa&. ?athes pro!"ce tr"ly ro"n! objects that cannot be a!e in any

other &ay.,n electric otor is the "niversal choice to po&er stationary tools. :ortable electric tools ay

be either cor!e! or batterypo&ere!.

%oon po&er tools incl"!e the !rill vario"s types of sa&s the ro"ter the electric san!er an!the lathe.

The ter po&er tool is also "se! in a ore general sense eaning a techni("e for greatlysiplifying a coplex or !iffic"lt tas$.

1. PO'ER HACKSA'>

, po&er hac$sa& is a type of hac$sa& that is po&ere! either by its o&n electric otor )also$no&n as electric hac$sa&+ or connecte! to a stationary engine. ost po&er hac$sa& are stationary

achines b"t soe portable o!els !o exist. tationary o!els "s"ally have a echanis to lift "p the

sa& bla!e on the ret"rn stro$e an! soe have a coolant p"p to prevent the sa& bla!e fro

overheating.

#hile stationary electric hac$sa& are reasonably "ncoon they are still pro!"ce! b"t sa&s po&ere! by a stationary engines have gone o"t of fashion. The reason for "sing one is that they provi!ea cleaner c"t than an angle grin!er or other types of sa&.

Fig. Po+er Hak!a+

Han@9He:@ ir-:ar ,a?,>

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The ter circ"lar sa& is ost coonly "se! to refer to a han!hel! electric circ"lar sa&

!esigne! for c"tting &oo! &hich ay be "se! less optially for c"tting other aterials &ith the

exchange of specific bla!es. %irc"lar sa&s can be either left or right han!e! !epen!ing on the si!e of

the bla!e &here the otor sits an! &hich han! the operator "ses &hen hol!ing a sa&.

Fig. ,iru'ar !a+ BPora'e)

(. %RILL>

, !rill is a tool &ith a rotating !rill bit "se! for !rilling holes in vario"s aterials. -rills arecoonly "se! in &oo!&or$ing etal&or$ing. pecial !esigne! !rills are also "se! in e!ical an!

other applications s"ch as in space issions.

The !rill bit is grippe! by a ch"c$ at one en! of the !rill an! rotate! &hile presse! against the

target aterial. The tip of the !rill bit !oes the &or$ of c"tting into the target aterial either slicing off

thin shavings )t&ist !rills or a"ger bits+ grin!ing of sall particles )oil !rilling+ or cr"shing an!

reoving pieces of the &or$ piece )asonry !rill+.

. BENCH "RIN%ER>

, bench grin!er or pe!estal grin!er is a achine "se! to !rive an abrasive &heel )or &heels+.

-epen!ing on the gra!e of the grin!ing &heel it ay be "se! for sharpening c"tting tools s"chas lathe tools or !rill bits. ,lternatively it ay be "se! to ro"ghly shape etal prior to &el!ing or fitting.

engineering workshop

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