mechanical one line notes

8/16/2019 mechanical one line notes

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1. TOOLS

1.0 Bench work and fitting

1.1 Vices: - used for holding work. Size is specified by width of Jaws and Maximum opening

between the Jaws.* Bench ice is also !ngineer"s parallel #ice and also known as fitter"s #ice.

* $eg #ice is used by black smith for hea#y work. Suitable for hea#y hammering and cutting

work.

* %ipe #ice used for holding round section tubes& pipes.

* 'and #ice is used for holding light work and for gripping ri#ets& keys& screws and

small drills etc.

* %in #ice is used for holding small diameter works such as wires and pins.

* (ool maker"s #ice useful for holding small work.

1.) Hammers + used to deli#er blows. Made from forged steel and specified by its weight.

*. Ball peen hammer is also known as !ngineer"s hammer. (his is chiefly used for chipping and

ri#eting.

* ,ross peen hammer is used for bending& stretching& hammering.

Straight peen hammer used for stretching or peening etc.

* Soft hammer is also called mallet made of wood& hard rubber& lead and copper.

1.-. Chisels + are used for cutting and chipping away pieces of metal. Made of high carbon steel.

* lat chisel is used for general chipping operations.

* ,ross cut chisel is also known as cape chisel. /sed for cutting groo#es in large surface.

* 0ound nose chisel useful for cutting oil groo#es in bearings.

* iamond point chisel used for cutting #+groo#e

1.2 iles iles are used to cut& trim or finish a 3ob of metal or wood. 4t is specified by its lengthand made from high carbon steel or tungsten steel. 5 file can remo#es the metal only on the

forward stroke. iles are classified into four types.

6a7 8n the basis of length 6b7 on the basis of shape

6c7 8n the basis of grade. 6d7 8n the basis+of cut

* 0ound and half round files are used for round cutting& filing cur#ed surfaces and enlarging holes.

* 9nife edge file used for filing narrow slot& notches and groo#es.

* 5 rough file used for cutting soft metals and trimming the rough edges of casting of soft metal.*5 second cut file used for harder metals.

* 4n single cut file teeths are cut at an angle of about :;< to the centre line of the file.

* 4n double cut file teeths are cut at an angle of :; and the up cut at an angle of =; to the centre

line.

* 0aps files useful for filing wood& plastic hard rubber etc.

1.> Scra!es these are used for sha#ing or parting off thin slices or flaks of metal to make a fine&smooth surface. ?enerally these are made from old files.

1.: Hacksaw + 'acksaw bladesthese are made from high carbon steel 6or7 high speed steel. (hemetal is remo#ed during the forward stroke and the return stroke is an idle stroke.


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* Soft metals and plastics are being cut by coarse tooth saw.

* (ool steel& medium+hard steel& copper alloys are cut by the medium tooth saw.

1.= "arking tools+

Surface plate is used for testing the flatness of work itself and also used for marking out work.

$arger 3obs marking out table is used. 4t is made of gray cast iron.* Scriber are use to scribe lines on metal.

* %unch is used in bench work for marking out work& locating center etc. Made of high carbon

steel.

* ,entre punch angle @;. /se to make a centre at a drilling point.

* ot punch angle is :;. 4t is used to make perm ant marking.

* %rick punch angle is -;+2;. /seful for marking on 3obs of thin metal sheets.

* +Blocks are made of cast iron used for holding round bars during marking and drilling.

*5ngle plate is made of grey cast iron. 4t is used to hold the work in a #ertical position for laying

out.

* (ry sAuare is use to set another edge or surface exactly at right angle to the already true edge or

surface.

#.0 orging Took:-

1.1 $n%il + 4t pro#ides support when force is applied to the forced component. 4t is made of cast steel or wrought iron 0ound hole pro#ided on the face of an#il is known as prichel hole

and sAuare hole is known as hardie hole.

).). Swage &lock + Made of cast steel or cast iron. /sed for sAuaring& sizing& heading& bending

and forming operations.

).- Tongs + /sed to hold the 3ob and are made from mild steel.

).2 Swages (hey are used for work which has to be reduced and finished to round& sAuare or hexagonal form. (hese are made from high carbon steel.

).> Chisels + (hese are made from high carbon steel.

* ,utting angle most commonly used of a cold chisel is :;;>


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* ,utting gauge has a cutting knife held& in position by a wedge and used for gauging finedeep fines.

-.2 C'tting Tools+

Saws + 4t is specified by the length of the blade.

* 0ip saws are used to cut alone the grains of wood. * ,ross cut saws are used+to cut across the grains of wood. 4t is also known as hand saw.

* %anet saw is used mainly for fine and accurate cuts& and sometimes for ripping as well as

cross cutting.

*(enon saw is also known as Back saw. 4t is mostly used for cross cutting for finer and more

accurate finish. (eeth are in the form of eAuilateral triangle.

* o#etail saw is similar to tenon saw. /sed where greatest accuracy is reAuired.

* ,omposs saw is also known as turning saw it is used for cutting small cur#es.

* Bow saw is used for cutting Auick cur#es.

* ,oping saw is used for small radius cur#es.

* %ad saw is used for cutting keyholes.

-.> Chisels + (hey are dri#en into wood using blows.

* irmer chisel used for taking winder cuts and finishing flat surfaces.

* o#etail chisel used do#etail 3oints and other +groo#es.

* Mortize chisel used for to take hea#y cuts.

-. : +lanning Tools + (he planning tools or planes are cutting tools which are used for sha#ing

or smoothing plane surfaces.

-.= Striking Tools

* ,law hammers are used for dri#ing nails and extracting nails out of wood.

* Mallet is a wooden hammer.

-.D Holding Tools+

* Slash cramp is also known as Bar ,ramp or (+,ramp. 4t is used for holding wider works.

*?+,ramp is used of smaller work.* 5 %incer is a tool used for pulling out nails from wood.

#. ",$S,",/T $/ /S+,CTO/

1.; Linear "eas'rement+

1.1 /on +recision nstr'ments + 5ccuracy is limited to 1rnm to ;.>mm.

* Steel rule is a direct measuring 4nstruments to read on accuracy of ;.>mm and 1E :2th of an

inch. (hey are made of hardened Steel. * ,alipers are used to transfer and compare a dimension from one ob3ect to another.

* Jenny or hermaphrodite caliper is used for scribing line parallel to edge of a cylindrical 3ob.

* (elescopic gauge is used for measuring the inside size of the slots or holes.

* epth gauge is used to measure depth of holes& groo#es and slots.

1.) +recision instr'ments+

!xternal micrometer used to measure external dimensions like diameter of shafts& thinness of

parts to an accuracy of ;.;1mm.

6b7British standard i.e.& !nglish micrometer has an accuracy of ;.;;1inch.

5 Screw micrometer is used for measuring pitch diameter of screw threads.


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5 depth micrometer is used to measure depth of holes to an accuracy of ;.;1mm and ;.;;1inch.

4nside micrometer is used to measure diameter of holes up to an accuracy of ;.;1 mm.

ernier caliper is used to measure both outside and inside diameters of Shafts& thickness of

parts etc. to accuracy is up to ;.;) mm and ;.;;1inch.

Slip gauges are precision gauge blocks used for precise measurement of parts.

ial indicator is a mechanical comparator and accuracy is up to ;.;1 min

5 pneumatic comparator is specially used in automatic size control

).; $ng'lar "eas'rements+

).1 /on !recision nstr'ments+

6a7 Be#el protectors are used to measure angles but not #ery accurate.

5d3ustable be#el gauge is used for checking& comparing or transferring angles.

,ombination set consist of three parts& they are sAuare head& center head and be#el protector.

).) +recision nstr'ments+

ernier Be#el %rotector is used to measure of angle to an accuracy of 1E1) 6or7 > minuses of a

degree.

Sine bar is a most accurate instrument used for measuring angles. 4t is specified by its distance

between centres of two rollers. 1;;mm length is most common.

6c7Sprit le#el is widely used for the static le#eling of machinery and other eAuipment.

5uto collimator is an optical instrument used for measurement of small angular differences&straightness and alignment.

-.; Ta!er "eas'rement+

5 taper angle is measured by the following measuring instruments.

6a7 Be#el protector. 6b7 (ool room microscope

6c75uto collimating (elescope 6d7 Sine bar and dial gauge 6e7 0ollers slip gauges andmicrometers.

2.; S'rface "eas'rement

6a7Straight edges are commonly used for testing the straightness and flatness of plate surfaces.latness is checked by a light test.

6h7Surface gauge is used to scribe lines at a gi#en #ertical height.

>.; *a'ges ?auges are tools which are used for checking the size& shape and relati#e positions of #arious parts. But not pro#ided with graduated ad3ustable members.

* %lug gauge is used for checking holes of different shape and size.

* 0ing gauge is used for testing external diameter.

* (aper gauge are used to test tapers of both internal and external. (hey are made in both plug

and ring style.* snap gauge are used for checking external dimensions. Shafts are mainly checked by snapgauge.

* (hread gauges are used to check the pitch diameter of threads.

* Screw pitch gauge is consists of a number of flat blades which are cut out to a gi#en pitch

and pi#oted in a holder. 4t is used to check the pitch of screw threads.

* 0adius and fillet gauges are used to check the radii of cur#ature of con#ex and conca#e

surfaces.

* eeler gauges are used to check clearance between matching surfaces.


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* (he thickness of sheet metal is checked by means of plate gauge and wire diameter by meansof wire gauge.

",T$LS

Metal is a mineral which is used in all works of !ngineering. Metals are mainly two types i.e.&ferrous metals and Fon

errous metals.

1.; +h(sical !ro!erties + Geigh& construction& color& Magnetization& conducti#ity and melting

point are physical properties of metal.

).; "echanical !ro!erties

* 'ctilit(: + (he ability of metals to deform under tensile load is called ductility. (he metalswith this property can be easily drawn into wires. !x+Mild steel.

*Brittleness is the ability of a metal which break or fail before much deformation take place.!x + ,ast 4ron.

* ,lasticit( + (he ability of a material to regain its original shape after deformation when theexternal forces are remo#ed. Steel is most elastic material.

* Stiffness 4t is the ability of material to resists deformation under stress.

* +lasticit( + 4t is the property of material which regains the deformation produced under load

permanently. (his property is necessary for forging metals.

* "allea&ilit( 4t is the ability of material to deform under compressi#e load. (he metals with

this property can make into thin sheets. !xample + 5luminum& tin lead.* To'ghness it is property of material to resist fracture due to high impact loads like hammer

blow.

* esilience 4t is the property of a material to absorb energy and to resist shock and impact

loads. (his property is essential for spring metals.

* Cree! + Ghen a part is sub3ected to a constant stress at high temperature for a long period of

time. 4t will undergo a slow and permanent deformation called creep. (his property isconsidered in designing 4.,. !ngines& turbines etc.

* Hardness + 4t is the ability of material to resist scratching& wear& abrasion& cutting&indentation and penetration.

* atig'e + ailure of material under re#ersal stress is called fatigue.

* 2eld a&ilit( 4t is the ability of material to be 3oined by welding.

* Cast a&ilit( + ,ast ability of metal refers to the ease with which it can be cast into differentshapes.

-. +ig ron + (he product of blast furnace is pig iron. 4ron ore& ,oke& $imestone Blast of air are reAuired to produce pig 4ron. $ime stone acts as a flux and forms impurities into a liAuid

slag. (he important ores of 4ron are 'ematite& Magnetite& $imonite& %yrite and Siderite.

Cast iron + (he product of the coupla is cast 4ron. %ig iron& steel scrap& ,oke and lime stone

are reAuired to produce cast 4ron. ,ast 4ron is an alloy of 4ron& carbon and silicon. (he carbon

content ranges from ) to 2H.

* T(!es of cast ron

6a7 ?ray cast 4ron6b7 white cast 4ron 6c7 Spheroidal gray ,.4. 6d7 Malleable cast 4ron 6e7 5lloy

cast 4ron.

2ro'ght ron + 4t is pure 4ron. 4t is approximately @@H. %ure 4ron and remaining carbon slag is left.

*4t is soft and can be easily forged and welded.

* 4t is manufactured by melting white pig 4ron in puddling furnace.


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* used for+nuts& chains& crane hoots& railway +cowling& pipe and pipe fittings& boiler tubes+etc.

-.- Steel: Steel is fundamentally an alloy of 4ron ,arbon with the carbon content #arying up

to 1.>H.

* Steel is manufactured by the following processes.

6a7 8pen 'earth process 6b7 Bessemer process 6c7 uplex process6d7 !lectric process 6e7 $ process 6f7 ,rucible steel process

* Steel can be di#ided into two types i.e.& 6a7 %lain carbon steel 6b7 5lloy steel

* %lain carbon steels are classified based on carbon content is

1. $ow carbon steel

). Medium carbon steel

-. 'igh carbon steel.

Low Car&on steel + 4f carbon percentage is less than ;.15H is called dead mild steel. ,arbon percentage is ;.1>+ ;.->H then steels are called mild steel.

'igh ductile and soft.

/sed for Futs& bolts& ri#ets& ,hains& nails& wires& and thin Sheets.

"edi'm Car&on Steel + (he carbon percentage is from ;.->H to ;.:H.

0elati#ely harder& toughest and less ductile.

/sed for making connecting rods& shafts& axles& crank shafts& pulleys& wire tops rails etc.

High car&on steel + (he carbon percentage is from ;.:H to ;.@H for tool steels carbon

percentage #aries from ;.@H to 1.>H.(his is #ery hard and tough.

4t acAuires permanent magnetic properties.

/sed for making springs& an#il faces files& cold chisels& punches& dies and cutting tools.

$lle( Steel + Steel that contains one or more alloying elements is called alloying steels.

'igh speed steel 6'SS7 is a alloy steel used for cutting tool. (he most common type is known

as 1D + 2 +1 'SS and contains 1DH tungsten& 2H chromium& and ly anadium. 'SS is

extensi#ely used for drills& $athe& planner tools and milling cutters.

Stainless steel is a corrosion resistance steel it has 1DH ,hromium DH Fickel and mostcommonly known as 1DED stainless steel. /sed for surgical 4nstruments& 9itchen eAuipment&utensils etc.

4n#ar contains nickel up to -:H. 4t has low coefficient of expansion. 4t is used for measuring4nstruments& clocks etc.

2.; /on-ferro's "etals (he metals that do+not contain 4ron are called Fon ferrous metals.

2.1 $l'min'm + 4t is mainly produced from bauxite ore. 4t is of white blue color. 4t occurs in

* * abundance on the surface of earth.

* 4t is good conductor of heat and electricity. * $ight in weight& #ery malleable and can be rolled into thin sheet.

* Melting point is ::;


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* 4t is good conductor of heat and electricity.

* 4t is used as a producti#e coating for 4ron and Steel sheets.

* 4t is used to make brass and bronze.

* 4ts melting point isI 2);< ,.

2.2 Tin + 4t is sil#ery white metal obtained from tin stone.

* Soft and malleable.

* 4ts melting point is )-; Lead + $ead is a hea#y metal and extracted from ?alena. 4t is of bluish brown colour.

* 4t is #ery soft& malleable& ductile and tough.

* Melting point is -);,.

* /sed in manufacture of storage batteries& electric cable co#erings& soft solder& lead pipes&

fuse wires etc.

*4t is a bright white metal. 4ts melting point is @:;,.

>.; /on - erro's allo(+S.Fo

5lloy ,omposition /ses

1

)

-

2

>

:

=D

@

1;

11

1)

1-

uralumin

Brass

Muntz Metal

Fa#al Brass

Monel Metal

Bronze

Bell metal.?un metal

Solder

Babbit metal

Fichrome

Ghite metal

?erman sil#er

[email protected]& ,u+2H& Mn+;.>H

Mg + ;.>H& Si + ;-H.

,u+=;H& n +-;H

,u+:;H& n +2;H

,u+:;H& n+-@H& Sn+ 4 H

Fi+:;H& ,u+-DH& 51+)H

,u+=; to @>H Sn +)> to >H

,u+D;H& Sn+);H,u +D-H& Sn+1;H& n+)H

Sn+:- to 2)H& %b+-=to >DH

Sn+DDH& ,u+2H& Sb+=H

Fi+D;H& ,r+);H

Sn+->H& ,u+>H& 54+1;H

,u+>>H& n+)>H& Fi=+);H

Building aero plane structures& automobile parts etc

/tensils& ,ondenser tubes etc

!lectrical fittings& ,ondenser tubes.

Marine pans

Steam turbine Blades and impeller of pumps

tc.

Making coins& statues and ornaments etc.

Making bells and gongs.

Making guns& bearing and boiler fittings.

Soldering.

Making crank shaft+ bearing

!lectrical hearten& 4ron& cookers etc

$arge bearings of light load

8rnaments& and resistance coils etc.

5luminum. ,u K ,opper& Mn KManganese& Mg K Magnesium& Si K Silicon& Sn K(in& %b Klead& +,r+,hromium.


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2. M!(5$ J84F4F? %08,!SS!S

1. "etal 4oining !rocess Metal 3oining process is the process 3oining of similar or+dissimilar

metal by the application of heat. 4t is classified as follows

6a7 Gelding 6b7 Soldering. 6c7 Brazing

#. 2elding 4t is process of 3oining similar metals by the application of heat& with or without

the application of pressure and with or without the addition of filler metal.

-. T(!es of welding fusion or non+pressure welding. (he metal at the Joint is heated to a

molten state and then allowed to solidify. Since no pressure is applied in this process

!x ?as welding& !lectric arc welding& (ermite welding

+ress're or !lastic welding (he metal pans are heated to a plastic state. (hen they are pressed together to make the 3oint. 4t is also known as pressure welding. Fo filler metal is

reAuired for pressure welding.!x !lectric 0esistance welding& forge welding.

5. *as welding 4t is a type of fusion& non pressure welding. (his reAuired heat to melt the

metal parts is supplied by a high temperature flame obtained by a mixture of two gases.

* lame temperature of different gases

* 8xy + acetylene 6-);;


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ight ward or &ackward welding 4t is also known as forehand welding. (he weld is madefrom left to right.

*4nclination of the blow pipe with the work surface is between 2; to >;and filler rod with thework surface is -; to 2;.

Vertical welding 4t does& not reAuire any edge preparation for plate thickness up to 1>mm.

*4nclination of the nozzle of the blow pipe with #ertical work surface is depends on plate

thickness and is in between )>to @;.

* iller rod with the #ertical work surface is nearly -;.

>.; ,lectric arc welding (he source of heat for electric arc welding is an electric arc. (he arcis produced between an electrode and the work

* 5ir gap between work and the electrode is approximately -mm.

* (he temperature at the centre of the arc is>>;;c to :;;;,.

* 5, or , Supply can be used for arc welding * or 5, welding supply& transformers are used to step down the usual supply #oltage 6);;+

2;;#7 to the normal open circuit winding #oltage >;+@8.

* Gelding is going onL arc #oltage is of the order of 4D+2;#.

>.1 Com!arison of C and $C arc welding

* , arc welding is suitable for both ferrous and non ferrous metals. 5., arc welding is notsuitable for non ferrous metal.

* 5rc stability is more in .,. whereas less in 5.,

* Fon coated bare electrodes can be used in ,. 8nly coated electrodes are used in 5., arcwelding.

* 4n , arc welding positi#e terminal connected to the work and negati#e terminal to the

electrode. Ghereas in 5., any terminal can be connected to the work or !lectrode.

* ., is less efficiency. Ghereas 5, more efficiency.

>) ,lectrodes for $rc welding !lectrodes for arc welding are classified into two categories

Cons'ma&le electrodes (hey get consumed during the welding operation. (hey are may be

either bare or coated type.

* Bare electrode has limited applications like minor repair of poor Auality work of welding.

* !lectrode coated with flux material such as asbestos.

* lux coated electrodes main functions are to stabilize arc& pro#ide a protecting atmosphere

and formatting of slag.

/on-Cons'ma&le electrodes (hese are made of carbon& graphite or tungsten. Ghich do not

consume during welding process.

:.; $rc welding "ethods (he electric arc welding is classified in to

657 Metal 5rc welding 6B7 ,arbon 5rc welding

6,7Submerged 5rc welding 67 Metal inert gas 6M4?7 5rc welding6!7 (ungsten inert gas 6(4?7 5rc welding metal arc welding.

:.1 "etal arc welding (he consumable flux coated electrode is used. Both 5, and ,

welding machines are used. (he angle between gee+electrode and work should be =;


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:.2 "etal inert gas8"*9 welding 4t is a gas Shielded metal arc welding process which usesthe high heat of an electric arc between a continuously fed& consumable electrode wire and the

material to be welded for 5luminum or copper& or argon helium mixture are used. (itanium

reAuires pure argon.

:.> *as T'ngsten $rc welding 8T*9 4t is similar to M4? welding except+electric are

between a non consumable tungsten electrode and the material to be welded. 5rgon is morewidely used for shielding. (his process is not used as often on plate o#er :.2mm thick.

=.; esistance welding 4n resistance welding the metal parts to be 3oined are heated to a plastic state o#er a limited area by their resistance to the flow of an electric current and

mechanical pressure is used to complete the weld. (here are two copper electrodes in thecircuit

'eat generated in watt hours 'K 4) 0(

Ghere 0 K0esistance& 4 K current in amps& ( K time

oltage used is #ery low 2 to 1)#.

* T(!e of resistance welding.

S!ot welding Spot welding is used to 3oin o#erlapping& sheets or plates of metal at small areasthis weld be used to weld steel and other metal strips up to 1) mm thick.

Seam welding 4t is a continuous type of spot welding o#er two o#erlapping metal sheets or plates. 4nstead of using pointed !lectrode& roller type copper electrodes are used.

+ro4ection welding 4n this welding a number of spots can be welded in one closure of the press.

B'tt welding there are two types of butt welding namely& 6i7 upset Butt welding and 6ii7 flash

butt welding.

!set B'tt welding (he two parts to be welded are placed in contact by clamping edge to

edge in copper Jaws. 4t is extensi#ely used for 3oining bars or pipes end to end.

lash B'tt wielding in this type& the two parts to be welded are clamped in copper Jaws of the

welding machine and brought together in a light. ,ontact or with a small air space betweenthem. 4t is used for welding body& tubes& wheels axles and flame in the automobile contraction

work.

D.; Thermit welding 4t is a fusion welding process. (he welding is done by pouring super

heated liAuid thermit steel around the parts to be welded. (hermit steel is a mixture of finelydi#ided aluminum powder and 4ron oxide at the ratio of 1- by weight. 4t is used for welding

#ery hea#y parts as Joining of rails& cables& shafts& broken machinery frames and broken teeth

of large gears etc.

@.; 2elding defects

+oor f'sion 4t is usually caused by insufficient heat and too fast tra#el of electrode.

nder c't 4t is due to excessi#e wea#ing speed& big electrode& and excessi#e current.+orosit( (he formation of blow holes& gas pockets& on the surface of the weld. (his is due to

the presence of gases in the metal& moisture in the flux and presence of rust& grease.

Cracks ue to incorrect welding techniAue or using a filler metal ha#ing a different rate of

contraction compared to that of parent metal.

S!atter 4t refers to the small particles or globules of metal scattered around the #icinity of

weld along its length.

1;.; flame C'ing 4ron and steel sheets and plates can be cut by using oxy+acetylene is based

on the fact that ferrous metals are sub3ected to oxidation.


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11.0 Soldering Soldering is the process of Joining two pieces of metal by adding a fusiblealloy or metal called solder. 4t is used as a filler rod. (he work pieces are not+ melted in the

soldering process.

* 5 Soldering is an alloy of lead and tin.

* 4t has a low melting temperature in the+range of 1>; + ->;;H tin sock

6iii7%lumber"s solder K lead =;k tin -;H

6i#7 !lectrician"s Solder K lead >DH.& tin 2)H +

1).; &ra7ing 4t the process of 3oining two similar or dissimilar metals by a fusible alloy calledCspelterC. 4t is similar to soldering except that speller is used instead of solder.

* (he Most commonly used flux in brazing is borax.

* luorides& chlorides and boric acid also used as a flux.

* (he melting point of the+ filler metal in brazing should be abo#e 2);


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Slitting Shearing is conducted between& rotary blades. 4t cuts the sheet metal length wise.

Lancing (his makes a cut part way across a strip.

ni&&ing ,utting any shape from sheet metal by nibbing machine.

Trimming 4t is the operation of curing away excess metal in a flange or flash from a piece.

-.) Bending 4t occurs when forces are applied to localized areas& such as in bending a piece of metal into a right angle and forming occurs when complete items or parts are shaped.

-.- rawing it is a operation of producing thin walled hollow or #essel shaped parts from

sheet metal.

-.2 S)'ee7ing 4t is a Auick and widely used way of forming ductile metal. (he sAueezing

operations of sizing& coining& bobbing& ri#eting etc.

2.; Sheet metal =oints

Hem 4t is an edge or border made by following. (hree common type of hems are single hem&double hem and wired edge.

Seam 4t is a 3oint made by fasting two edges together. Most common type of seam are

La! Seam $ap 3oint by soldering.

Single seam /sed to 3oin a bottom to #ertical bodies

The do'&le Seam its formed edge is bent upward against the body.

The do%etail seam /sed to 3oin flat plate to a cylindrical piece.

>. ",CH$/C$L 2O;/* O ",T$LS

1.; 4t is simply plastic deformation performed to change dimensions& properties and surface

condition of a metal by means of mechanical pressure.

* 4f plastic deformation abo#e re+crystallization temperature but below melting point is hot

working. * 4f plastic deformation below re+crystallization temperature is cold working.

Hot working methods

Hot rolling 0olling is the most rapid method of forming metal into desired shape by plastic

deformation in between rolls.

* bars& plates& sheets& rails and other structural sections like 4+section& channel section& !Aual

angle and (+sections. !tc is manufactured by rolling.

+iercing 4t is the process employed for the manufacturing of seamless tubes.

rawing 4t is the process of making cup shaped parts from flat sheet metal blanks.

Hot s!inning it is a process of making circular sections from sheet metal. 4t is carried on lathe

,6tr'sion 4t is a process in which heated billet or slug of metal is forced by high pressure

through an orifice that is shaped to pro#ide the desired form

0ods bghgg* G++ks brass cartridges& lead co#er cables& aircraft parts and many hardware items

are typical product of extrusion.


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Searks less tubes in mass production are manufactured by the extrusion process.

1.) Cold working methods

Cold drawing (he operation in#ol#es the forcing of metal through a die by means of a tensile

force applied to the exit side of the die. 5ll the wire that is a#ailable is produced by colddrawing through dies.

Cold S!inning 4t is the operation of shaping #ery thin metal by pressing it against a formwhile it is rotating.

* /sed in making of bells on musical instruments& light fixtures& kitchen ware& and large processing kettles.

Cold e6tr'sion 4t is similar to that of hot extrusion. ,ollapsible medical tubes and toothpastetubes are made in this method.

Cold heading 4t is a cold forging process& used primarily for the manufacture of bolts& screws&ri#ets and similar items.

Thread rolling 4t is used for mass production of threaded parts.

otar( swaging 4t is the process used to reduce the cross sectional area of rods and tubes.

Coining %rocess in#ol#es the impression and rising of images or characters from a punch anddie into the metal.

* ,oins& medals and other such similar parts are produced by this process.

=. H,$T T,$T",/T

1.; heat Treatment 'eat treatment can be defined as the process of changing the structure

and properties of metal by controlled heating and cooling.

+'r!oses of heat treatment

* (o relie#e the internal stresses.

* (o refine the grain size so as to impro#e the mechanical properties

* (o impro#e the mach inability.

* (o increase corrosion and wear resistance.

1.1Critical tem!erat're Ghen steel is heated at high temperature& then at a certaintemperature change starts in the internal structure. (he temperature at which this change starts

take place is called critical temperature.

1.) Lower critical tem!erat're (he temperature at which the change in structure start taking

place is called lower critical temperature. (his is about =)-


14/35

Hardening 4t is the process of heating steel to a temperature within or abo#e its critical rangeand then cooling it rapidly in oil or water or other suitable solutions.

* (he purpose of 'arding is to de#elop high hardness& wear resistance and ability to cut other materials.

Tem!ering 4t is the process of heating the hardened steel below lower critical temperature&holding at this temperature for sufficient time and slow coolie

* (empering reduces the hardness& brittleness and increases toughness.

Car&'ri7ing 4t is a process whereby carbon is absorbed into the surface of steel alloys. 4t

consists in heating of steel to a red heat& in contact with some carboneous material.

* (he process is carried out on low carbon steels for producing hard surface.

/itriding 4t is a process of case hardening ferrous alloy of suitable composition by absorptionof nitrogen. (his is done by heating in an atmosphere of ammonia.

C(aniding 4t is a ,ase hardening process in which both carbon and Fitrogen added to thesurface layers of the steel.

nd'ction hardening 4t is a surface herding process in which the part to be surface hardenedis placed within an induction coil through which a high freAuency current is passed.

lame hardening 4t is a surface 'arding process in which the part is heated to hardeningtemperature with an oxy+acetylene flame.

D. o'ndr(

1.; o'ndr( 4t deals with the process of making castings in moulds prepared by patterns.

1.1 Casting 4t is the process of pouring molten metal& into mould and allowing it to solidify

* 4n order to prepare a component by casting the following are reAuired.

6a7 pattern 6b7molding sand 6c7 molten+material

1.# T(!es of !atterns

Most commonly used types of patterns are single piece pattern& split pattern

Match plate pattern& cope and drag pattern& gated pattern& loose piece pattern& sweep pattern&shall pattern etc.

* Gooden pattern are used for small sized production schedules

* Metal patters are used for large size production

* Match plate patterns are used for small castings in large Auantities.

* Sweep patterns are used for symmetrical mouth particularly in large sizes.1.- +attern allowance

Shrinkage allowance 4t is pro#ided to compensate for the #olumetric loss of metal during

cooling in the moulds. 4t is added to pattern made larger size by an amount eAual to that of shrinkage.

"achining allowance 4t is pro#ided on the pattern in order to get reAuired surface finish for the casting. 4t is added to pattern.

raft allowance 5ll #ertical Surfaces of the pattern are pro#ided taper allowance so that pattern can be remo#ing easily. 4t is a positi#e allowance.

Color codes of !atterns


15/35

* Surface to be left unfinished + Black

* Surface to be machine + red

* Seats for loose pieces+ 0ed stripes on yellow back ground.

* ,ore prints+ + Nellow

1.2 "o'lding tools and e)'i!ments

Sho%el used for mixing and tempering moulding sand.

iddle 5 riddle sometimes called a screen. /sed for remo#ing foreign material such as this&shot metal& splinters of wood etc.& from moulding sand.

ammers /sed to pack the sand e#enly around the pattern

Slick /sed for repairing and finishing the mould surface and edges after the pattern has been

withdrawn.

Lifters /sed for remo#ing the sand particles from the mould.

Swa& /sed for moisturizing the edges of sand mould.

Vent rod /sed to make series of holes in the sand of a mould to permit gases to escape.

raw s!ike /sed to remo#e the pattern from the mould

Trowels /sed to shape and smoothen the surface of the mould and for doing minor repairs

Bellow /sed to blow loose particles of sand from the pattern and the mould ca#ity.

"o'lding Bo6 (op part of Box is called cope& bottom part is called drag and middle part is

called cheek.

1.> T?+,S O "OL/* S$/

*reen Sand 4t is a mixture of silica sand with 1D to -;H ,lay& and moisture : toDH. used for small and medium size castings.

r( sand Ghich is free from moisture& used for making large casting

Lome sand it contains >;Hclay. 4t is particularly employed for large casting.

acing sand forms the face of the mould. /sed to pre#ent the metal from burning into the

sand.

Core Sand used for making cores sometimes called oil sand.

+arting sand /sed to keep the green sand from sticking to the pattern and also to allow the

sand on the parting surface of the cope and drag to separate without clinging.

1.: +O+,T,S O "OL/* S$/

+orosit( 4t is the property of the sand which allows the gases and steam to escape through thesand.

low a&ilit( 4t is the ability to beha#e like a fluid so that& it will flow to all portions of amould and take up reAuired shape.

Colla!si&ilit( 4t is the property due to which the sand mould collapses after solidification of

the casting to allow a free ,ontraction of the metal.

$dhesi%eness %roperty due to which it is capable of adhering to another body.

Cohesi%eness (his is the ability of sand particle to stick together.

efractoriness (he ability of sand to with stand high temperature of the molten metal withoutfusing.

1.= "OL/* +OC,SS


16/35

loor mo'lding %roduction of Medium and large castings.

+it mo'lding moulds of large 3obs are generally prepared in a pit dug in the foundry floor.

Bench mo'lding or small casting which are light in weight.

"OL/* "achines

S)'ee7er "achine moulding sand in the flask is sAueezed until the moulds attain the desireddensity.

=olt machine (he action of raising and sudden dropping of the table the sand get packed and

rammed. (he sand is rammed hardest at the parting plane and around the pattern and remainsless dense in the top.

=olt s)'ee7e machine + a combination of sAueeze and Jolt action is often employed.

Sand Slinger 0amming is obtained by the impact of sand which falls at a #ery high #elocity.

1.@ S+,C$L "OL/* +OC,SS,S

* ,o) moulding process uses sodium silicate as the binder. Silica gel formation occurs in ,o)

moulding.

* (herino setting 0esin is used as the binder for shell moulding.

* Gax patterns are used in 4n#estment casting.

)&; +,"$/,/T "OL C$ST/*

* ery high rate of production is achie#ed in die casting and tolerances of the order of ;.;)>

mm.

* Semi centrifugal casting is used to obtain gears& disked wheels& pulleys etc.

* (rue centrifugal is 4deal for hollow cylindrical castings such as bushings& gun barrels& cast

4ron pipes etc.

* 4n centrifugal casting& cores are not reAuired for hollow castings.

).1 *$T/* $/ S,/* O C$ST/* * ?ating system is pro#ided to continuous& uniform feed of molten metal with as littleturbulence as possible to themould ca#ity.

* Sprue is a #ertical passage through the cope and connects the pouring basin with the runner or gate.

* 0iser permit the molten metal to rise abo#e the highest point in the casting after the mouldca#ity is filled up.

@. "$CH/, TOOLS

Lathe "achine

$athe (he main function of a lathe is to remo#e metal in the form of chips from a work pieceto gi#e it the reAuired shape and size& this is accomplished by holding the work securely and

rigidly on the lathe and then rotating it against a cutting tool.

Specification of a lathe (he size of a lathe is specified by6i7 'eight of centers from the bed 6ii7 Maximum swing o#er bed

6iii7Maximum swing o#er carriage. 6i#7 Maximum distance between centers


17/35

6#7 8#erall length of the bed.

(ypes of lathe

* Speed lathe has no carriage& gearboxL used for wood working& polishing and spinning.

!ngine or center lathe widely used for many operations like turning& facing& taper turning &thread cutting& drilling etc.

.* Bench lathe is used for small and precision works.

(ool room lathe is used for #ery precision turning of tools& gauges and dies.

(urrent and capstan lathe are production lathes used for mass production.

5utomatic lathes are high speed& hea#y duty and mass production lathes with completeautomatic.

Special purpose lathes are designed to perform certain specified operations only. !g. ,rank

shaft& uplicating lathe.

1.- + unctions of lathe parts

Bed Base of the lathe. 5ll parts are located on the bed. (he bed has flat or in#erted guideways.

8uter ways pro#ides bearing and sliding surface for the carriage

4nner ways pro#ide ways for tail stock.

5utomatic chip disposal is ad#antage in in#erted +guide ways.

Made gray cast iron alloy with nickel and chromium.

(he bed material should ha#e high compressi#e strengths& wear resistance and good absorb of

#ibration.

'ead Stock Secured permanently at the left end of the bed.

* 4t carries a hollow spindle and a li#e centrecan be fitted into the hollow spindle.

(he spindle got external thread and taper is 1);.

a back gear is pro#ide minimum speeds to the spindle.

'ead stock can run at different speeds using 6a7 Belt dri#e on cone pulley 6b7 5ll geared 'eadstock

6c7 ariable speed motor.

*(ail Stock $ocated on the inner ways at the right hand end of the bed.

it is used for supporting the right end of the work piece by means of a dead centre.

4t holds a tool for performing operations liked drilling etc.

4t can be also used for taper turning operation.

,arriage it is supported on the lathe bed ways and can mo#e in a direction parallel to the lathe

axis. 4t consists of saddle& cross slide& compound rest& tool post apron.

Saddle carries the cross slide& compound rest and tool post. 4t mo#e along the guide ways.

,ross slide carries the compound rest and tool post. 4t can be mo#ed by hand or by power feed.

,ompound rest is mounted on the cross slide. 4t carries a circular base called swi#el plate

which is graduated in degrees. 4t is used to set the tool for angular cuts& 4t mo#ed by means of hand wheel.

* (ool post is fitted o#er the compound rest. (he tool is clamped in the tool post.

$ower part of the carriage is termed as the apron. 4t is attached to saddle and hangs in front of

the bed.


18/35

eed mechanism (he lathe tool can be gi#en three types of feed& namely& longitudinal& crossand angular.

eed rod is a plain long shaft used to mo#e the carriage or cross slide all operations expectthread cutting.

(he lead screw is a long thread shaft is used to trans#erse the tool along the work to producescrew threads. (he half nut or split nut makes the carriage to engage or disengage the lead

screw.

(ypes of feeds when the tool mo#es parallel to the lathe bed axis& called longitudinal feed& thisis achie#ed by mo#ing the carriage.

Ghen the tool mo#es perpendicular to the axis of the lathe bed axis the mo#ement is called

cross feed& this is achie#ed by mo#ing the cross slide.

Ghen the tool mo#es at an angle to the axis of the lathe& the mo#ement is called angular feed&

this is achie#ed by mo#ing the compound slide.

1.> Gork holding and supporting de#ices + (he de#ices employed for holding and supportingthe work piece and the tool on the lathe are also called its accessories.

,hucks Gorks of short length& large diameter and regular and irregular shapes can be held inchucks the chuck is mounted on the spindle of the lathe.

(hree 3aw is also called self centering chuck. 4t consists of a cylindrical body ha#ing three 3awsfixed radially at its front. Ghen the chuck key is tightened the work is centered automatically.

our 3aw is also called independent chuck. 4rregular or eccentric 3obs can be held in this chuck.

,ollect chuck used for holding bars of small sizes. 4t is normally used in capstone and

automatic lathe.

Magnetic chuck is used for holding thin 3obs of magnetic materials.

,enters are used for work holding in a lathe. 5 li#e center rotates with the work piece and a

dead centre is stationary which supports the right end of the work piece.

(he included angle of the centre is :o degree and is machined to standard morse taper.

8rdinary centre is used for general works and half centre is used for facing operation without

the remo#al of the centre.

ace %late 4t is a circular plat screwed to the lathe spindle. 4t consists of radial& plain and (

slots. $arge and irregular 3obs which can hold on face plate by bolts and clamps.

5ngle %late 4t has two faces at right angle to each other& holes and slots are pro#ided on both

faces to held the work in #ertical

Mandrels 4t is used for holding hollow work piece between centers.

,atch %late or ri#ing %late 4t is a circular plate and transfer motion to the dog fitted with the

work piece. 4t is used to dri#e the work piece through the dog or carrier& when the work piece is

held between centers.

,arrier or og 4t is used to transfer motion from the rotating catch plate.

Supporting de#ices /sed to long support work pieces.

Steady rest is fastened to the lathe bed at a con#enient point.


19/35

ollower rest is bolted to the carriage and thus it supports the work immediately behind thetool throughout the trans#erse.

1.: $athe 8perations

(urning (ool is fed parallel to the lathe axis and cylindrical surface is produced.acing 4t is the operation of machining of the end face of work to make it flat. (he tool is feed

perpendicular to the axis of lathe.

?roo#ing 4t is the process of reduces the diameter of a work piece o#er a #ery narrow surface.

4t is also called under cutting or necking.

%arting 4t is the operation of cutting the work piece. 5fter it is machined to the desired size and

shape.

9nurling 4t is the process of embossing a diamond shaped regular pattern on the surface of a

work piece. 4t is done to gi#e a good gripping surface on the work piece.

rilling 4t is the operation of making a hole in the work piece. 4t is done when the 3ob rotates&

the drill bit is fed into the work pieces by turning the tail stock hand wheel.

Boring 4t is the operations of enlarging a hole& produced by drilling& boring is used when

correct drill is not a#ailable.

0eaming 4t is the operation of finishing a drilling or bored hole to accurate size. (he reamer is

held in the tail stock spindle.

Magnetic chuck is used for holding thin 3obs of magnetic materials

,hamfering 4t is the operation of be#eling the extreme end of the work to protect the end of the work piece from being damaged. 4t is an essential operation to be performed after thread

cutting.

(aper (urning 5 taper is defined as the uniform Se in the diameter of a work piece measured

along its length.

5ngle of (aper 4f "" is large diameter& OdO is small diameter& 1" is length of tapered part& then

+ d

(an aK l

Ghere PaO is angle of taper or half taper angle

,onicity 4t the ratio of the difference between diameters of the taper to the length of taper.

+d

,onicity 697 K++++++

l

(aper turning methods

6a7(aper turning by the compound rest (he compound rest may be swi#elled and set at thedesired half taper angle and tool is fed by rotating the compound rest wheel. 4t is suitable for

short but steep tapers.

6b7 orm tool (his method is applicable for short work only taper turning is done by a form

tool.

(aper attachment 4t is suitable for any length of the 3ob. 4nternal taper can also be turned.


20/35

(ail Stock Set 8#er 4n this method the tail stock may be set o#er by loosing the nut from itscentre line. /sed for turning small taper on long 3obs and external taper one

+ d

Set o#er 6s7K )

1.D (hread ,utting 4t is the operation to produce helical groo#e on a cylindrical or conical

surface by feeding the tool longitudinally& the rotation of lead screw is used to tra#erse the tootalong the work to produce screw threads.

(he longitudinal feed should be eAual to the pitch bf the thread to be cut per e#olution of the

work piece.

Speed of spindle %itch of lead screw

Speed of lead screw %itch of thread to be cut4 case of cutting right hand threads& both the spindle and the lead screw will rotate in the same

direction and carriage must mo#e towards head stock.

or cutting left hand threads& the spindle and lead screw will rotate opposite to each other and

carrage must mo#e away from the head stock.

1.@ ,apstan and turret lathes in these lathes tail stock is absent and it is replaced by hexagonal

turret.

5utomatic indexing and bar feeding mechanism is used to reduce the time reAuired to producea component.

* 5ltogether 12 different tools can be mounted in the lathes.

* /sed for mass production.

(urret lathe s ,apstan $athe

* (he turret of turret lathe is directly mounted on the bed. (he turret of a capstan1athe is

mounted on a short slide which slides on saddle.

(urret lathe pro#ide almost rigidity to the tool support& in capstan lathe& o#er hanging of ram present anon rigid ,onstruction.

(urret lathe is suitable for hea#y 3obs. ,apstan lathe is suitable for bar works.

1.1;. efinitions

Steed Speed is the rate of rotation of work piece& express in re#olution per minute 6rpm7 anddenoted by F.

,utting Speed 4t is the speed at which metal is remo#ed by the tool from the work piece. &

,utting speed 6#7 11FE1;;; mEmin

Ghere is the diameter of the work piece in mm.

eed eed is the distance the tool ad#ances for each re#olution of the work piece. 4t is expressin mmEre#.

ept of cut 4t is the perpendicular distance measured from the machined surface to the uncut

surface of work. 4t is expressed in MM.

epths of cut K d1+d)E)

4f d1 K diameter of work before machining& d)K diameter of work after machining.


21/35

04$$4F? M5,'4F!

rilling 4t is the operation of producing hole in the work piece by using a rotating cutter calleddrill. 4n the drilling machine& the work piece is held stationary and as the drill rotates it is fed

into the work piece.

(ype of drilling machines

%ortable drilling machine it is #ery small and compact drilling machine. it may be operated byhand or by an electric motor.

(he maximum size of drill it ,all hold is up to 1Dmm.

* (his machine is specified by the maximum drilling capacity.

Serit rilling Machine it is a light seed machine tool. it is mounted on a bench it is called bench type and if mounted on face it is floor type.

4t is specified by the diameter of the largest work piece that can be drilled.

* 4t can drill holes from 1.>mm to 1>mm diameter.

(he drill is fed into the work piece by hand only using rack and pinion arrangement.

/pright drilling machine 4t is similar to sensiti#e drilling machine except that it has power

feed mechanism for rotating drill and it designed for medium size work.

* 0ound column drilling machine is also known as pillar drilling machine.

(he box column machine is more rigid than a round column machine.

(he maximum size of holes can be drill up to >;mm.

0adial rilling Machine 4t is used for drilling large and hea#y work pieces.

(hree mo#ements are possible in a radial drilling machine to locate the drill Auickly o#er any point on the work.

4t ha#e an additional swi#elling ad3ustment in either the head or the arm and can drill holes atany angle.

* 4t is specified by the length of the arm and column diameter.

?ang rilling taws Machine Ghen a number of single spindle drilling machine columns are

placed side by side on a commonbase and ha#e a common work table. 5 series of operation can

be done on the 3ob.

Multi spindle tingling machine (hese machines ha#e se#eral spindles dri#en by a single motor

and all+spindles are fed simultaneously.

)) rilling Machine 8perations 8perations that can be performed in a drilling machine are

rilling 6b7 0eaming 6c7 ,ounter boring 6d7 ,ounter sinking 6d7 (apping

,ounter Boring 4t is the operation of enlarging one end of a drilled hole. (he enlarged holeforms a sAuare shoulder with the original hole. ,ounter boring is done to accommodate the

heads of bolts& studs and pins.

,ounter Sinking 4t is the operation of making a cone shape enlargement of the end of a hole. 4t

is done to accommodate flat head screw or counter sank ri#et fitted into the hole.

(apping 4t is the operation of cutting internal threads by means of a cutting tool called tap.

(ap grill size the size of the tap is eAual to the outside diameter of its threads. (herefore the

drilled hole must be smaller than the tap by twice the depth of the thread.

rill sizeK (ap size + ) x depth of thread


22/35

).-(ool holding e#ices (he different methods are used for holding the drill in a drill spindleare

6a7 By directly fitting in the Spindle (he tool shank is forced into the tapered hole of thespindle and the tool is gripped by friction. (he tool may be mo#e from the taper hole using a

drift.

rill Slee#e 4f the taper shank of the tool is smaller than the taper in the spindle hole& a taper

drill slee#e is used.

rill Socket Ghen the tapered tool shank is larger than spindle taper& drill sockets are used to

hold the tool.

rill ,huck (he drill chuck is used to hold smaller size driers. 4t has two or more ad3ustable

3aws set radially to hold straight shank drills.

12 (wist rill Fomenclatures

6a7(ang 4t is the flattened end of taper shank. 4t fits into the slot in the machine spindle.

Shank 4t may be to tapered or straight. Morse taper is used for taper shank.

$ip of cutting edge 4t is the edge which actually cuts the material.

lutes lutes are helical groo#es cut on the body of the drill. (he functions of flutes are toform the cutting edges& to allow the chips to escape and to allow the cutting fluid to reach the

cutting edges.

%oint 5ngle %oint is the cutting end of the drill and point angle is the angle it between the

cutting lips. (he usual point angle is 11D degrees& but for harder& steel alloys& the angle

increases.

).> 1 rill Sizes 4n metric system drills are commonly manufactured froth ;.) to 1;;

mm. in British system the drills are manufactured in three different sizes

Fumber sizes (he drill size #aries from Fo. 1 to Fo. D;.

$etter sizes 4n this system the drill sizes range from 5 to .

6c7 ractional sizes 4n this system the drill sizes range from 1E:2 inch to > inch.

,utting Speed 4t is expressed in mEmin

n F

,utting speed 67 1;;; mEmin

is the diameter of the drill. F is the rpm of the drill spindle.

eed (he feed of a drill is the distance the drill mo#es into the work at each re#olution of the

spindle. 4t is expressed in mmEre# or per min.

(he feed per min K feed per re# x rpm

epth of ,ut (he depth of cut in drilling is eAual to one half of the drill diameter.

(Kd mm

)

-.; Boring machines (hey are used to bore holes in large and hea#y parts like engine drams&engine cylinders& machine housing.


23/35

-.1 types of Boring machinesL

'orizontal Boring Machines Gork is supported on a table which is stationary and the tool

re#ol#es in horizontal axis.

ertical Boring Machine (he work rotates on a horizontal table about a #ertical axis and the

tool is stationary except for feeds.

Jig boring Machine it is the most actuate of all machine tools. /sed for production of Jigs&

ixtures& (ools and other precision parts. (he machining accuracy is a firm.

S'5%4F? M5,'4F!

Shaper Shaper is a reciprocating type of machine tool intended& primarily to produce flat

surface. 'ere tool is allowed to reciprocate.. 2.1 ,lassification of Shapers Shapers are classified as follows.

647 according to the type of design of the table

6a7 Standard shaper. 6b7 /ni#ersal shaper

5ccording to the position and tra#el of the ram

6a7 'orizontal type 6b7 ertical type

5ccording to the type of dri#ing mechanism used for gi#ing reciprocating motion to the tarn.

,rank type 6b7 'ydraulic type 6c7 ?eared type

5ccording to the esign of table

a7 Standard Shaper (he table as two mo#ements only& #ertical and horizontal to gi#e the feed.

/ni#ersal shaper (able can be tilted about two more axes. 8ne axis is parallel to the ram axisand other perpendicular to the first axis. 5 uni#ersal shaper is mostly used in tool room work.

5ccording to the position and tra#el or the ram z

'orizontal type ram reciprocates along 'orizontal direction. (hey are used mainly to

produce flat surface.ertical (ype ram reciprocates along #ertical axis. (hey are used for machining internalsurface& keyways& slots and groo#es.

5ccording to the type of dri#ing mechanism used for gi#ing reciprocating motion to the ram.

,rank Shaper 4t uses a crank mechanism to con#ert circular motion of a large gear called bull

gear into reciprocating motion.

?eared Shaper 0eciprocating motion of the ram is obtained using rack and pinion mechanism.

'ydraulic Shaper 0eciprocating motion is obtained using hydraulic power. 4nfinite number of

cutting speeds can be obtained from zero to the maximum #alue and the control is easier.

2.-. Specifications of a shaper (he size of the shaper is specified as follows.

6i7 Maximum length of stroke 6ii7 (he maximum size of cube that can be held in a

shaper.

5 number of other details are reAuired to specify a shaper fully.

6i7Maximum #ertical ad3ustment of the table 6ii7 %ower of the dri#e motor

6iii7 (ype of dri#ing mechanism 6i#7 (ype of shaper

6#7 loor space and net weight


24/35

2.2 Quick 0eturn Mechanism (he Auick return of the ram can be obtained by any one of thefollowing mechanisms

6a7 ,rank slotted link mechanism 6b7 Ghitworth Auick return mechanism

'ydraulic mechanism

(he a#erage time ratio of cutting stroke to return stroke in a shaper is -).2.> Shaper operations (he basic operations performed on a shaper are machining horizontal

surface& #ertical surface& angular surface& cutting slots keyways and machining irregular surface.

2.: ,utting Speed ,utting speed is the speed at which the tool tra#erses through the material.

,utting Speed K $ength of the cutting stroke

(ime taken for the cutting stoke

eed 4t is the relati#e mo#ement of tool or work in a direction perpendicular to the mo#ementof the ram. 4t is express in mm per stroke. (he feed is always gi#en at end of return stroke.

epth of ,ut 4t is the thickness of metal remo#ed in one cut 4t is expressed in mm.

S$8((4F? M5,'4F!

>.; Slotter Slotting machine is a reciprocating type of machine tool similar to a shaper. (he

main difference is that in a slotter the ram holding the tool reciprocates in a #ertical axis& whereas in a shaper the ram holding the tool reciprocates in a horizontal axis.

>.1 (ypes of stotters

%uncher Stotter (hey are hea#y duty machines& eAuipped with a powerful motor and can cut

metal at a #ery high speed.. 4t consists of a sAuare or circular table.

Stoner Specifications (he size of a slotter is specified by the maximum length of the stroke of

the ram. (he size of a slotter usually ranges from D;to @;;mm.

%recision Slotter . 4t is a lighter machine and it is operated at high speeds. 4t is designed to take

light cuts gi#ing accurate finish. these are usually fitted whit worth Auick return mechanism.

(o specify the machine fully the following particulars are also gi#en.

617 (he diameter of the table in mm6ii7 ,ross and longitudinal mo#ement of the table

6iii7 Fumber of speeds and feeds 6i#7 %ower of the motor and

6#7 loor space reAuired .

Slotter 8perations (he following operations are performed on a slotter

647 lat surface machining 6ii7 ,ircular surface machining

6iii7 4rregular surface and can machining 6i#7 ,utting slots& keyways and groo#es

%$5F4F? M5,'4F!

%laner is the largest reciprocating type machine tool. 4t is primarily intended to produce plane

and flat surface by a single point cutting pool. (he main difference between a shaper and a

planer is that in a planer the work is mo#ed against a stationary tool and the is fed into thework. Ghere as in a shaper the tool mo#es across the stationary work and fed across the tool.


25/35

:5 (ypes of planning machine

Standard or ouble housing planer 4t consists of two massi#e #ertical housing connected by a

cross rail.

8pen side planer 4t has a housing on one side of the base only as a cantile#er. 4t allows large

and wide 3obs.

%it %laner (he table is made stationary and the columns carrying the cross rail are made to

reciprocate. 4t is used for #ery large work.

!dge or plate planer 4t is used for sAuaring and be#elling the edges of steel plates for different

pressure #essels and ship building works.

i#ided table planer 4t consists of two tables on the bed which may be reciprocated separately

or together. (his type of design sa#es idle time while setting the work.

:.) ri#ing Mechanism Mechanisms used for dri#ing the table of planer are

6a7 ,rank dri#e 6b7 8pen ,ross belt dri#e 6c7 ., re#ersible motor dri#e

.

6d7 'ydraulic dri#e.

:.- Specification of a planer 4ts size is gi#en by the largest rectangular solid that can

reciprocate under the tool. 4t is known by

(he horizontal distance between the two #ertical housings.

ertical distance between the table top and the cross rail when the latter is in its top most

position.Maximum length of table tra#el or length of stroke.

%laner 8perations (he common operations performed in a planer are

617 %lanning flat horizontal surface

8il7 %lanning cur#ed surface

6ii7 %lanning #ertical surface

6i#7 %lanning slots groo#es

6#i7 Machining do#etails %laning at an angle

:.> planer s Shaper

%laner is specially adopted to large work. Ghereas the shaper can do only small work.

8n the planer the work is mo#ed against stationary tool but on shaper the tool mo#es across thework which is stationary.

4n a planer& work setting reAuired much of skill and where as shaper work may be clamped

easily and Auickly.* 8n the planer the Auick return mechanism is incorporated for the table but in a shaper theAuick return mechanism is used for dri#ing the ram.

* %laner tool are much more robust that used in a shaper.

M4$$4F? M5,'4F!


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Milling 5 milling is a machine tool that remo#es metal in the form of chips by a rotatingmulti point cutter. 4t remo#ed metal in the form of chips by a rotating multipoint cutter. 4t

remo#es metal at a #ery fast rate.

(ypes of milling machines

,olumn and knee type 4t consists of a column and a knee which can be mo#ed up and down& along cross and longitudinal directions.

6a7 %lain milling machine table consists of three mo#ements only

6>7 /ni#ersal milling machine fourth motion of table i.e. 0otation is apart from standard table

motions.

6c7 ertical milling machine (he spindle of the machine is #ertical. (he machine is used for

machining groo#es& slots and flat surface.

=.) Specification of milling machine (he size of column and knee type milling machine is

specified by

6i7 Maximum length of longitudinal& cross and #ertical tra#els of the table.

=.- Milling 8perations (he different operations performed in the milling machine are

%lain milling %lain milling is the operation of producing plain& flat and horizontal surface

parallel to the axis of rotation of the cutter& including slots and groo#es. (his also called slab

milling& when #ery wide plain milling cutter is used.

ace Milling 4t is performed by a face milling cutter rotated about an axis perpendicular to

the work piece.

Side Milling 4t is the operation of producing a flat #ertical surface on the side of work piece

using a side milling cutter.

!nd Milling 4t is the operation of a flat surface which may be horizontal& #ertical or inclined to

the table. 4t is also used for producing slots& groo#es and keyways.

5ngular Milling 4t is the operation of producing an angular surface on a work piece. (he

angular groo#e may be single or double angle.

?ang Milling 4t is the operation which in#ol#es the use of a combination of more than two

cutters.

Saw Milling 4t is the operation of producing narrow slots or groo#es. %arting off operation can

also be done using the slitting saw.

(+Slot Milling 5 (+Slot is produced using a (+Slot cutter. (he (+slot milling cutter is a special

form of end mill.

orm milling 4t is the operation of producing the reAuired profiles on the work piece. (he

profile may be conca#e& con#ex or any other shape.

?ear ,utting (he gear cutting operation may be done using a form cutter& ha#ing formed,utting edges of in#olute shape.

=.2 (ool holding de#ices 5rbors 4t is a short shaft. (he cutters ha#ing a bore at the centre are

mounted on the arbor.

,ollects 4t is used to hold straight shank milling cutters.

5daptors 4t is used to hold& shank type cutters whose shank is smaller than that of hole in thespindle.

=.> Milling processes


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/p milling 4t is also called ,on#entional Milling. 4t is the process of remo#ing metal by amilling cutter rotated against the direction of tra#el of the work piece. (he cutting force in up

milling increases from zero to the maximum #alue per tooth mo#ement of the cutter.

own milling 4t is also called climb milling. Metal is remo#ed when the cutter teeth mo#e

downwards. 'ere the cutter rotates in the same direction as the tra#el of the work piece.

smile apart from standard table motions.

?04F4F? M5,'4F!S

-.; ?rinding 5 metal cutting operation performed by means of rotating abrasi#e wheel thatacts as a cutting tool called grinding. 5ccuracy in dimension is in the order of )> microns.

9inds of ?rinding

0ough or non precision ?rinding Snagging and off hand grinding are examples for rough

grinding& examples for this are trimming of surface left by the sprues and risers on castings&remo#al of flash on forging etc.

%recision ?rinding (his is connected with producing good surface finish and high degree of

accuracy. (he type of surface to be ground& is classified as6a7 !xternal cylindrical grinding 6h7 4nternal ,ylindrical

6c7 Surface grinding 6d7 orm grinding

?rinding machines

0ough ?rinders (he remo#al of stock without any reference to the accuracy. (hey are mainly

of the following type

6a7 Bench floor stand grinders 6b7 portable flexible shift grinders

6c7 Swing frame grinders 6d7 abrasi#e belt grinders

%recision grinders 5re those that finish parts to #ery accurate dimensions.

6a7 ,ylindrical ?rinders 4t is primarily used for grinding plain cylindrical parts& contoured,ylinder& tapers etc. (here are four mo#ements in#ol#ed in a cylindrical centre type grindingL

Gork must re#ol#e

6ii7 (he wheel must re#ol#e

6iii7(he work must mo#e past the wheel 6i#7 (he wheel must mo#e past the work.

%lain center type grinders are essentially a lathe on which a grinding wheel has been

substituted for a single point tool.


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* 4n uni#ersal centre type grinder& the head stock spindle can be swi#elled& at an angle in ahorizontal plane.

6b7 ,entreless grinders 4t is a method of grinding exterior cylindrical& tapered and formedsurfaces on work pieces that are not held and rotated on centers.

* 4t reAuires a grinding wheel& regulating or back up wheel and a work rest.

,entre less grinding may be done in one at three ways& through feed& inked& and end feed.

(hrough feed is used for long and slender shafts& where no shoulders or other forms are not present.

enfeed is used for components ha#ing forms or shoulders.

!ndfeed is used for components to produce tapes components.

6c7

4nternal grinders /sed to finish straight& tapered or formed holes to correct size. (here are

three general types of internal grinders.6a7 ,hucking 6b7 %lanetary 6c7 ,entre less

Surface grinder (hey are employed to finish plane or flat surfaces and also capable of grinding

irregular& cur#ed& tapered surfaces.

(ool and cutter grinder (hey are used mainly to sharpen and recondition multiple tooth cutters

like remers& milling cutters& drills& taps etc.

6e7 Special grinding machines (hese are used to do highly specialized work. !x + ,rank shaft

grinders& piston grinders& thread grinders and tool post grinders.

D.- Gheel Materials

5brasi#es 4t is a substance used for grinding and polishing operations. (hey are classified into

two groups.

Fatural 4ncludes sandstone or Auartz& emery& corundum diamond.

5rtificial 4nclude chiefly Silicon carbide and aluminum oxide.

?rit& ?rade and structure of grinding wheel

?rit or grain it indicate the size of abrasi#e grains used in making a wheel.

* ,oarse Gheels are used for fast remo#al of materials and for soft and ductile materials.

ine grain wheels are used to grind hard and brittle materials. .

?rade 4t refers to the hardness with which the band holds the cutting point.

(he grade shall be denoted by a alphabet. 5 to ' indicates soft grade& 4 to % indicates medium

and Q to indicates hard grain.

Structure of ?rain Spacing (he structure refers to the number of cutting edges per unit area of

wheel face as well as to the number size of #oid spaces between grains& denoted by numbers.

Soft and ductile materials reAuire an open structure.

'ard and brittle materials reAuire dense structure.

@.; Surface finishing operations

'oning 4t is a grinding process for finishing round holes by means of bonded abrasi#e stones

hones.

* 5mount of material remo#ed is less ;.)> nun.

* 5utomobile cylindrical liners are honed for surface finish.

@1 $apping 4t can be used on flat cylindrical and spherical surface.* Metal that can be remo#ed is ;.;;> to ;.;1mm.


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* 4t is used for slip gauges& piston pins& roller bearings and optical parts.

@- Super finishing ?enerally all machining and grinding lea#e surface with fragmented& metal

which cause excessi#e wear and noisy operations. 4t is remo#ed using super finishing.

5 #ery fine grit abrasi#e stone is used.

* 5mount of material remo#ed is around about ;.;;> [email protected] Buffing 4t is a final operation to remo#e the polish of a metal and to bring maximum luster.

* %olishing wheels with fine abrasi#e particles are used.

%ickling 4t refers to the remo#al of surface oxides and scale from by acid solutions.

,ommonly pickling solutions contain sulphuric or hydrochloric acids.

4t is commonly done on rolled shapes& wires& sheets heat treatment steel parts.

* 4n some applications& such as on aluminum& pickling is called oxidizing.

@.: !lectro %lating 4t is the most popular means of applying metallic coatings on the surface of metals and sometimes on non+metals.

* (his is done for protection against corrosion or against wear and abrasion and for appearance.

(he four ,ommon plating metals are chromium& nickel& copper& zinc& and tin.

* (he four essential elements of a plating process are the cathode& anode& electrolyte and direct

current.

@.= 'ot ipping +. 5 protecti#e coating may be applied on by dipping them into certainmolten metal namely zinc& tin or an alloy of lead and tin.

* (he process of zinc coating on steel is called gal#anizing.

?ear cutting ?ears can be best produce on mass production by hobbing.

* ?ear finishing operation is called gear sha#ing. .

< (hin gears from sheet metal can be produced commercially by stamping.

?ear bobbing process is faster than milling because se#eral teeth cut at time. .

$5GS 8 M8(48F

1.; Mechanics 4t is the branch of %hysics which deals with action of forces.

9inematics deals with motion of bodies and not about magnitude of forces.

ynamics is the mathematical and physical study 8f the beha#ior of bodies under the action of forces that produce motion in a body.

Statics is the mathematical and physical study of the bodies in eAuilibrium under the action of

forces.

1.1 9inematics

isplacement is the shortest distance between initial and final position of the particle.

* Speed is the ratio of the distance tra#elled to time. 4t is a scalar Auantity.

(he displacement of a body in unit time is called #elocity.


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* 5 mo#ing particle is said to ha#e uniform #elocity when eAual displacement of particle takes place in eAual inter#als of time.

* Ghen n a body mo#es with uniform #elocity& its acceleration is zero.

* (he negati#e acceleration of a body is called 0etardation.

1.) !Auations of motion 5 body mo#ing with uniform acceleration "a". $et its initial #elocity

be PuO and attains a #elocity "". after co#ering a distance "sO in the time "tO.

$inear motion # K u R at L S K ut R 1 ate L #) a u) K ) as L S.K u 6n + 1E)7 a

"S." is the distance co#ered by the body in PnO th second.

1

ertical motion # K u gt Lhut T) gt) L #) + tr) K ) gh

1

,ircular motion =. w K w 2+ a iL DK ;7 R ) a t) L )) + 647 1)K ) a o

Ghere w K angular #elocity 6radEs7 a K angular acceleration 6radEs)7 ; K angular displacement

6rad7

u)

Maximum height reached by the #ertically thrown body "'O K

)@

* (ime of ascent is the time taken to reach the height by the body N K(ime of descent is the time taken to tra#el from highest point to the position from which it has

pro3ected upwards.

t K

(ime of flight of a body is sum of time of ascent and time of descent. ( K

1-

Motion in two dimensions

%ro3ectile 5 body which mo#es in a two dimension plane in the gra#itational field of earth is

called a pro3ectile.

(ra3ectory (he path followed by the pro3ectile is called tra3ectory. (he path of tra3ectory parabola.

)u Sin

* (ime of flight 6(7 K g

Ghere ";O is angle of pro3ection "u" is initial #elocity.

0ange 607 (he horizontal displacement undergone by a pro3ectile& when it returns to its initial

ele#ation.

Sin);

0K+

Maximum height (he maximum height of a pro3ectile is reached at a time when its #ertical

#elocity component has decreased to zero.

4n long 3ump& the maximum span of 3ump is obtained when the angle of take off is 2>.

Mass 4t is the amount of matter contained in a gi#en body. 4t does not #ary with the change inits position on the earth surface. 4t can be measured by Balance le#er.


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Geight 4t is the gra#itational force of attention of the body towards the centre of earth. 4t

#aries with place to place. Geight is measured by spring balance.

).; Fewton"s law of motion

Fewton"s first law (he momentum of body remains as along as no external force acts on it.

* irst law introduces the concepts of "force and inertia" and leads their definitions.

orce orce is that which changes or tends to change the state of rest or of uniform motion of a body.

4nertia 4nertia is the inability of a body to change its state.

Fewton"s Second law 0ate of change of momentum is directly proportional to applied force.

Kma& /nits

S. 4 ++ Fewtons ,.?.S++ dynes M.9.S.TkgmEs).

Fewton"s (hird law (o e#ery action there is an eAual and opposite reaction.

4mpulse 4s the product of force and time of application of force .

4mpulse 4t 647 Kx tKm 6 + u7

/nits ,.?.S++ dyne+sec S4 ++Fs

).1 $aw of conser#ation of momentum Ghen no external force acts on a system& the algebraicsum of the momentum of the bodies in the system remains constant any direction after any

number of collisions.

m) 11) K !nt #iR m) #)

u1 u) #elocities of bodies before collision 1 ) are #elocities after collision.

* 4f second body is mo#ing in opposite direction to first one before collision.

rn) u) K mt #i in) #)

Jet planes and 0ockets work on the principle of conser#ation of momentum 6or7 Fewton"s thirdlaw of motion.

0ecoil of a gun is due to the principle of conser#ation of momentum 6or7 Fewton"s third law of motion.

).) $aw of conser#ation of energy 5ccording le law of conser#ation of energy& energy can be

neither be created nor be destroyed& it ,an be transferred from one form to another form.

Mechanical energy is con#erted into electrical energy by a dynamo.

!lectrical energy is con#ened into heat energy is con#ened into heat energy and light energy byarc lights& electric bulbs and heaters.

Sound energy is con#erted into electrical energy by microphones.

4nternal combustion engines con#ert chemical or heat energy into mechanical energy.

* Gater falling from a certain height con#erts %.!. into 9inetic energy.

* Battery con#erts chemical energy into electrical energy.* Steam engine con#erts heat energy into mechanical energy.


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* %elton wheel con#erts potential energy into mechanical energy.

!lectrical motor con#erts electrical energy into mechanical energy.

-.; 0otational motion

5 body is said to ha#e rotate. Motion when it mo#es in a circular path about a fixed point or about an axis.

!g (he motion of a grinding wheel& a fly wheel and the rotatory motion of the earth about its

own axis.

(he angle subtended by an arc of length eAual to its radius& at its centre is called radian. 8neradian is eAual to >=


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• 4f the lift mo#es up or down with uniform acceleration G-K mg

∗ 4n the case of a freely falling lift& the apparent weight of the person is zero.

>.; Gork& %ower and energyGork is the product of force and displacement measured in the direction of force. G K . S. ,os

a

/nits ,.?.S system !rg S i system Joules& 1 Joule K 1;= erg8ne kilo Gatt hour 69wh7 or unit is eAual to -: x 1;> 3oules.

∗ %ower is the time rate at which work is done.

%K GEt& /nits ,.?.S System K ergEsec& s.i. SystemK 3ES 6or7GattE

* !nergy is the capacity to do workL it has the same units as work.

• Mechanical energy is of two forms& potential energy and kinetic energy.

• %otential energy is the energy possessed by a body by #irtue of its position& p !K mgh

4

∗ 9inetic energy is the energy possessed by #irtue of its motion& 9. ! K1E) m#).*(he relation between momentum and energy is & 9.! K p)E)m where PpO is the momentum of

body.

∗ (wo bodies of different masses ha#e the same kinetic energy. Ghen hea#ier mass has

greater momentum than the lighter mass.

5 imensional formula+orce M4(+) Momentum and 4mpulse M.$(+ "

%ower M/(" Gork and energy M$) ()

5ngular #elocity r 5ngular acceleration+ i1E2)

Stress 4i2$+1(+) Surface tension M1)iscosity + Mi..+21C $atent 'eat 1) (+)!lectric charge 5( Moment of 4nertia M4U

?ra#itation constant Ma." lir %ressure M$+ir

Noung"s& modulus M/" r Specific heat $) () 9"

ectors and Scalarsector 5 physical Auantity which has magnitude and direction is called #etor. !.g.

isplacement& #elocity& momentum and force.

Scalar 5 physical Auantity which has only magnitude is called Scalar. !g. Mass& time& speed&

energy& #olume& density and work.D.; riction

∗ riction (he force which always opposes the motion of one body o#er there body in

contact with it is called the friction..

∗ Static friction (he maximum frictional force present when a body 3ust tends to slide o#er

the surface of another body is called the static friction.

• ynamic friction (he frictional force present when one body slides o#er other body are known

as dynamic friction or kinetic friction.0olling friction Ghen a body like awheel& cylinder& or drum rolls o#er the. Surface of another

body the friction is called roiling frictionD.). ,oefficient of friction

* (he ,oefficient of friction between two surfaces is the ratio of the frictional force to the

normal reaction. p K

Ghere "11 is the ,oefficient of friction. " is the frictional force. "0" is the Formalreaction.

s kV p r p S is the coefficient of static friction 0.& is the coefficient of

kinetic reaction. p is the coefficient of rolling friction.


34/35

5ngle of friction 4ncase of limiting friction& if the normal reaction and the frictional force becompounded into a single force& which is referred to as resultant. (he angle which this resultant

makes with the normal reaction is called the angle of friction.

(an a K E0 K

D.2 (he laws of limiting friction

* riction always opposes motion.(he force of friction is proportional to the normal reaction between the two surfaces in contact.

riction is independent of the areas of the surfaces in contact& but depends on the material&nature and condition of thesurfaces in contact.

@.; %lanetary motion

$aws of uni#ersal gra#itation (he gra#itational force of attraction between two bodies is

directly proportional to the product of their masses and in#ersely proportional to the sAuare ofthe distance between their centres.

4rr1) ?mtnk

a or Kr)

Ghere "?" is the uni#ersal gra#itational constant.? K :.:= x 1;W2 dyne + cm) gm) in ,.?.S system.

K :.:= x 1;W+11 Fewton + m) kg) in S. 4. system.

?M0elation between "?" and "g" is g K

1;.; Simple harmonic motion

5 body is said to ha#e simple harmonic motion& if its acceleration is always directed towards a

fixed point on its path and is proportional to its displacement from the fixed point.

(he maximum displacement of the #ibrating particle on either side of the mean position iscalled its amplitude.%eriod of 8scillation 6t7 (he time for one complete 8scillation of the particle is called period of

8scillation or #ibration.

(K)11 ... aildisplacemmt K li

4 accleratioi areAuency 6n7 (he number of #ibrations made by the particle in unit time is called freAuency

* Simple %endulum (he period of a simple pendulum is directly proportional to the sAuare root

of its lengthK(K)rlage 6or7 gK211)1+++&-+1

(1$i

(05FSM4SS48F4

1.; * in transmission of power& mechanical& electrical& hydraulic and pneumatic dri#en are

employed. Belts& ropes& chain dri#es and gears are examples of mechanical dri#es.


35/35

4.1 Belt and rope dri#esBelts or ropes are used to transmit power from one shaft to another by means of pulleys.

Belts are made of leather& rubber& cotton& balata& fabric.

1) (ypes of Belts 5ccording to the speed of the dri#e belts classified into the following threegroups.

6a7 $ight dri#es (hese are used to transmit small powers at belt speed up to about 1; mEs& as inagricultural machines and small machines tools.

6h7.Medium dri#es (hese are used to transmit medium power at belt speeds o#er 1; mEs but

up to )) mts& as in machine tools.6c7 'ea#y dri#es (hese are used to transmit large powers at belt speeds abo#e )) mEs& as in

compressors and generators.5ccording to the shape& belts are classified into three types.

6a7 lat belts 6b7 +belts 6c7 ,ircular belts or ropes

1- lat Belts (hese are used to transmit power& from one pulley to another when the two pulleys are not more than D meter apart.

(he standard flat belt thicknesses are >& :.>& D& 1; and 1) mm.1.2 types of flat belt dri#es

8pen belt dri#e

4t is used for shafts arranged in parallel and rotating in the same direction.* 5ngle of contact is less in these belts& when compared with cross belts.

Documents

mechanical one line notes