This document provides an overview of milling(machining). It defines milling as a machining process that uses rotary cutters to remove material from a workpiece by advancing the cutter into the workpiece. There are two main classes of milling processes: face milling which cuts flat surfaces using the end corners of the cutter, and peripheral milling which cuts along the circumference of the cutter to produce shapes like slots and gears. Milling cutters come in different types for various milling operations. The document also discusses factors that affect the surface finish produced by milling and different types of milling like gang milling. It provides details on milling equipment, operations, and the basic parts and functions

1. Milling(machining)
Millingisthe machiningprocessof usingrotary cuttersto remove material[1]
fromaworkpiece
advancing(orfeeding) ina directionatan angle withthe axisof the tool.[2][3]
Itcoversa wide varietyof
differentoperationsandmachines,onscalesfromsmall individual partstolarge,heavy-dutygang
millingoperations.Itisone of the mostcommonlyusedprocessesinindustryandmachine shopstoday
for machiningpartstoprecise sizesandshapes.
There are twomajor classesof millingprocess:
 In face milling,the cuttingactionoccurs primarilyatthe end cornersof the millingcutter.Face
millingisusedtocutflat surfaces(faces) intothe workpiece,ortocut flat-bottomedcavities.
 In peripheral milling,the cuttingactionoccursprimarilyalongthe circumference of the cutter,
so that the cross sectionof the milledsurface endsupreceivingthe shape of the cutter.Inthis
case the bladesof the cuttercan be seenasscoopingoutmaterial fromthe work piece.
Peripheral millingiswellsuitedtothe cuttingof deepslots,threads,andgearteeth.
Millingcutters
Main article:Millingcutter
Many differenttypesof cuttingtoolsare usedinthe millingprocess.Millingcutterssuchas endmills
may have cuttingsurfacesacrosstheirentire endsurface,sothattheycan be drilledintothe workpiece
(plunging).Millingcuttersmayalsohave extendedcuttingsurfacesontheirsidestoallow forperipheral
milling.Toolsoptimizedforface millingtendtohave onlysmall cuttersattheirendcorners.
The cutting surfacesof a millingcutterare generallymade of ahard and temperature-resistantmaterial,
so that they wearslowly.A lowcostcuttermay have surfacesmade of highspeedsteel.More expensive
but slower-wearingmaterialsinclude cementedcarbide.Thinfilmcoatingsmaybe appliedtodecrease
frictionorfurtherincrease hardness.
Theyare cuttingtoolstypicallyusedinmillingmachinesormachiningcentrestoperformmilling
operations(andoccasionallyinothermachine tools).Theyremovematerial bytheirmovementwithin
the machine (e.g.,aball nose mill) ordirectlyfromthe cutter'sshape (e.g.,aformtool such as a hobbing
cutter).
Surface finish
A diagramof revolutionridgesonasurface milledbythe side of the cutter,showingthe positionof the
cutterfor each cuttingpassand howit correspondswiththe ridges(cutterrotationaxisisperpendicular
to image plane)

2. As material passesthroughthe cuttingareaof a millingmachine,the bladesof the cuttertake swarfsof
material atregularintervals.Surfacescutbythe side of the cutter (asin peripheral milling)therefore
alwayscontainregularridges.The distance betweenridgesandthe heightof the ridgesdependonthe
feedrate,numberof cuttingsurfaces,the cutterdiameter.[4]
Withanarrow cutterand rapidfeedrate,
these revolutionridgescanbe significantvariationsinthe surface height.
Trochoidal marks,characteristicof face milling.
The face millingprocesscaninprinciple produceveryflatsurfaces.However,inpractice the result
alwaysshowsvisibletrochoidalmarksfollowingthe motionof pointsonthe cutter'sendface.These
revolutionmarks give the characteristicfinish of aface milledsurface.Revolutionmarkscanhave
significantroughnessdependingonfactorssuchas flatnessof the cutter'sendface and the degree of
perpendicularitybetweenthe cutter'srotationaxisandfeeddirection.Oftenafinal passwithaslow
feedrate isusedto compensate fora poormillingsetup,inordertoreduce the roughnessof revolution
marks.In a precise face millingoperation,the revolutionmarkswill onlybe microscopicscratchesdue to
imperfectionsinthe cuttingedge.
Gang milling
Heavygang millingof millingmachine tables
Gang millingreferstothe use of two or more millingcuttersmountedonthe same arbor(thatis,
ganged) ina horizontal-millingsetup.All of the cuttersmayperformthe same type of operation,oreach
cuttermay performa differenttype of operation.Forexample,if severalworkpiecesneedaslot,aflat
surface,andan angular groove,agood methodtocut these (withinanon-CNCcontext) wouldbe gang
milling.Allthe completedworkpieceswouldbe the same,andmillingtime perpiece wouldbe
minimized.[5]
Gang millingwasespeciallyimportantbefore the CNCera,because forduplicatepartproduction,itwas
a substantial efficiencyimprovementovermanual-millingone featureatan operation,thenchanging

3. machines(orchangingsetupof the same machine) tocut the nextop.Today, CNCmillswithautomatic
tool change and 4- or 5-axiscontrol obviate gang-millingpractice toa large extent.
Equipment
Millingisperformedwith millingcutters attachedtoamillingmachine.
Types and nomenclature
Mill orientationisthe primaryclassificationformillingmachines.The twobasic configurations are
vertical andhorizontal.However,there are alternate classificationsaccordingtomethodof control,size,
purpose andpowersource.
Mill orientation
 Watch video
Vertical mill
Vertical millingmachine.1:millingcutter2:spindle 3:top slide oroverarm4: column5: table 6: Y-axis
slide 7:knee 8: base
In the vertical mill the spindle axisisverticallyoriented. Millingcutters are heldinthe spindle androtate
on itsaxis.The spindle cangenerallybe extended(orthe table canbe raised/lowered,givingthe same
effect),allowingplungecutsanddrilling.There are twosubcategoriesof vertical mills:the bedmilland
the turret mill.
 A turret mill has a stationaryspindle andthe table ismovedbothperpendicularandparallel to
the spindle axistoaccomplishcutting.The mostcommonexampleof thistype isthe Bridgeport,
describedbelow.Turretmillsoftenhave aquill whichallowsthe millingcuttertobe raisedand
loweredinamannersimilartoa drill press.Thistype of machine providestwomethodsof
cuttinginthe vertical (Z) direction:byraisingorloweringthe quill,andbymovingthe knee.
 In the bedmill,however,the table movesonly perpendiculartothe spindle'saxis,while the
spindle itself movesparallel toitsownaxis.
Turret millsare generallyconsideredbysome tobe more versatile of the twodesigns.However,turret
millsare onlypractical as longas the machine remainsrelativelysmall.Asmachine size increases,

4. movingthe knee upanddownrequiresconsiderable effortanditalsobecomesdifficulttoreachthe
quill feedhandle (if equipped).Therefore,largermillingmachinesare usuallyof the bedtype.
Horizontal mill
Horizontal millingmachine.1:base 2: column3: knee 4 & 5: table (x-axisslide isintegral)6:overarm7:
arbor (attachedto spindle)
A horizontal mill hasthe same sortof x–y table,butthe cuttersare mountedona horizontal arbor(see
Arbormilling) acrossthe table.Manyhorizontal millsalsofeature abuilt-inrotarytable thatallows
millingatvariousangles;thisfeature iscalleda universaltable.While endmillsand the othertypesof
toolsavailable toavertical mill maybe usedina horizontal mill,theirreal advantage liesinarbor-
mountedcutters,calledside andface mills,whichhave acrosssectionratherlike a circularsaw,but are
generallywiderandsmallerindiameter.Because the cuttershave goodsupportfromthe arborand
have a largercross-sectional areathanan endmill,quite heavycutscanbe takenenablingrapid
material removal rates.These are usedtomill groovesandslots.Plainmillsare usedtoshape flat
surfaces.Several cuttersmaybe gangedtogetheronthe arbor to mill acomplex shape of slotsand
planes.Special cutterscanalsocut grooves,bevels,radii,orindeedanysectiondesired.These specialty
cutterstendto be expensive.Simplex millshave one spindle,andduplex millshave two.Itisalsoeasier
to cut gears ona horizontal mill.Some horizontal millingmachinesare equippedwithapower-take-off
provisiononthe table.Thisallowsthe table feedtobe synchronizedtoa rotary fixture,enablingthe
millingof spiral featuressuchas hypoidgears.
A SiegX2 miniature hobbyistmillplainlyshowingthe basicpartsof a mill.

5. Metal lathe
Centerlathe with digital readout andchuck guard.Size is460 mmswingx 1000 mmbetweencenters
A metal lathe or metalworkinglathe isa large class of lathesdesignedforprecisely machiningrelatively
hard materials.Theywere originallydesignedtomachine metals;however,withthe adventof plastics
and othermaterials,andwiththeirinherentversatility,theyare usedina wide range of applications,
and a broad range of materials.Inmachining jargon,wherethe largercontextisalreadyunderstood,
theyare usuallysimplycalled lathes,orelse referredtobymore-specificsubtypenames(toolroom
lathe,turret lathe,etc.).These rigid machine tools remove material fromarotatingworkpiece viathe
(typically linear) movementsof variouscuttingtools,suchas tool bits and drill bits.
Construction
The designof lathescan varygreatlydependingonthe intendedapplication;however,basicfeaturesare
commonto most types.These machinesconsistof (atthe least) aheadstock,bed,carriage,and
tailstock.Bettermachinesare solidlyconstructedwithbroadbearingsurfaces(slide-ways) forstability,
and manufacturedwithgreatprecision.Thishelpsensure the componentsmanufacturedonthe
machinescanmeetthe requiredtolerancesandrepeatability.
Headstock
Headstockwithlegend,numbersandtextwithinthe descriptionrefertothose inthe image

6. The headstock (H1) housesthe mainspindle (H4),speedchange mechanism (H2,H3),andchange gears
(H10). The headstockisrequiredtobe made as robustas possible due tothe cuttingforcesinvolved,
whichcan distorta lightlybuilthousing,andinduce harmonicvibrationsthatwilltransferthroughtothe
workpiece,reducingthe qualityof the finishedworkpiece.
The main spindle isgenerallyhollowtoallow longbarstoextendthroughtothe work area.Thisreduces
preparationandwaste of material.The spindle runsinprecisionbearingsandisfittedwithsome means
of attachingworkholdingdevicessuchas chucksor faceplates.Thisendof the spindle usuallyalsohasan
included taper,frequentlyaMorse taper,to allow the insertionof hollow tubular(Morse standard)
tapersto reduce the size of the taperedhole,andpermituse of centers.Onoldermachines('50s) the
spindle wasdirectlydrivenbya flatbeltpulley withlowerspeedsavailablebymanipulatingthe bull
gear.Later machinesuse a gearbox drivenbya dedicatedelectricmotor.A fully'gearedhead'allows
the operatorto selectsuitable speedsentirelythroughthe gearbox.
Beds
The bed isa robustbase that connectsto the headstockandpermitsthe carriage and tailstock,tobe
movedparallel withthe axisof the spindle.Thisisfacilitatedbyhardenedandground bedwayswhich
restrainthe carriage and tailstockina settrack. The carriage travelsbymeansof a rack and pinion
system.The leadscrew of accurate pitch,drivesthe carriage holdingthe cuttingtool viaagearbox driven
fromthe headstock.
Typesof bedsinclude inverted"V"beds,flatbeds,andcombination"V"andflatbeds."V"and
combinationbedsare usedforprecisionandlightdutywork,whileflatbedsare usedforheavyduty
work.[citation needed]
Whena lathe is installed,the firststepisto level it,whichrefersto makingsure the bedisnot twistedor
bowed.There isnoneedtomake the machine exactlyhorizontal,butitmustbe entirelyuntwistedto
achieve accurate cuttinggeometry.A precisionlevel isauseful tool foridentifyingandremovingany
twist.Itis advisable alsotouse sucha level alongthe bedtodetectbending,inthe case of a lathe with
more than fourmountingpoints.Inbothinstancesthe levelisusedasa comparatorrather than an
absolute reference.(aboutabdulrehman)
Feedand leadscrews
The feedscrew(H8) isa longdriveshaftthatallowsaseriesof gearstodrive the carriage mechanisms.
These gearsare locatedinthe apron of the carriage.Both the feedscrew and leadscrew(H7) are driven
by eitherthe change gears (onthe quadrant) or an intermediategearbox knownasa quick change
gearbox (H6) or Nortongearbox.These intermediate gearsallowthe correctratioand directiontobe
setfor cuttingthreads or wormgears.Tumblergears(operatedby H5) are providedbetweenthe
spindle andgeartrainalongwitha quadrant plate thatenablesagear trainof the correct ratio and
directiontobe introduced.Thisprovidesaconstantrelationshipbetweenthe numberof turnsthe
spindle makes,tothe number of turnsthe leadscrew makes.Thisratioallowsscrewthreadstobe cut on
the workpiece withoutthe aidof a die.

7. Some latheshave onlyone leadscrew thatservesall carriage-movingpurposes.Forscrew cutting,a half
nut is engagedtobe drivenbythe leadscrew'sthread;andforgeneral powerfeed,akeyengageswitha
keywaycutintothe leadscrewtodrive apinionalongarack thatis mountedalongthe lathe bed.
The leadscrew will be manufacturedtoeither imperial ormetricstandardsandwill requireaconversion
ratioto be introducedtocreate threadformsfroma differentfamily.Toaccuratelyconvertfromone
threadformto the otherrequiresa127-tooth gear,or on lathesnotlarge enoughto mountone,an
approximationmaybe used.Multiplesof 3and 7 givinga ratio of 63:1 can be usedto cut fairlyloose
threads.Thisconversionratioisoftenbuiltintothe quickchangegearboxes.
The precise ratiorequiredtoconverta lathe withanImperial (inch) leadscrew tometric(millimeter)
threadingis100 / 127 = 0.7874... . The bestapproximationwiththe fewesttotal teethisveryoften37/
47 = 0.7872... . Thistranspositiongivesaconstant -0.020 percenterroroverall customaryand model-
maker'smetricpitches(0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.60, 0.70, 0.75, 0.80, 1.00, 1.25, 1.50, 1.75,
2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50 and 6.00 mm).
Carriage
Carriage withlegend,numbersandtextwithinthe descriptionrefertothose inthe image
In itssimplestformthe carriage holdsthe tool bitand movesitlongitudinally(turning) or
perpendicularly(facing) underthe control of the operator.The operatormovesthe carriage manually
viathe handwheel(5a) or automaticallybyengagingthe feedshaftwiththe carriage feedmechanism
(5c). Thisprovidessome relief forthe operatorasthe movementof the carriage becomespower
assisted.The handwheels (2a,3b, 5a) on the carriage and itsrelatedslidesare usuallycalibrated,both
for ease of use and to assistinmakingreproduciblecuts.Calibrationmarks will measure eitherthe
distance fromcenter(radius),orthe workpiece'sdiameter,soforexample,onadiametermachine
where calibrationmarksare inthousandthsof aninch,the radial handwheel dial will read.0005 inches
of radiusperdivision,or.001 inchesof diameter.The carriage typicallycomprisesatopcasting,known
as the saddle (4), and a side casting,knownasthe apron (5).
Cross-slide
The cross-slide (3) rideson the carriage and has a feedscrew thattravelsatrightanglesto the main
spindle axis.Thispermits facing operationstobe performed,andthe depthof cut to be adjusted.This
feedscrewcanbe engaged,throughagear train,to the feed shaft(mentionedpreviously)toprovide
automated'powerfeed'movementtothe cross-slide.Onmostlathes,onlyone directioncanbe
engagedata time asan interlockmechanismwill shutoutthe secondgeartrain.

8. Compoundrest
The compound rest (or top slide) (2) isusuallywhere the tool postismounted.Itprovidesasmaller
amountof movement(lessthanthe cross-slide) alongitsaxisviaanotherfeedscrew.The compoundrest
axiscan be adjustedindependentlyof the carriage orcross-slide.Itisused forturningtapers,tocontrol
depthof cut whenscrewcuttingorprecisionfacing,ortoobtainfinerfeeds(undermanual control) than
the feedshaftpermits.Usually,the compoundresthasa protractor markedinits base (2b),enablingthe
operatorto adjustitsaxisto precise angles.
Tailstock
Tailstockwithlegend,numbersandtextwithinthe descriptionrefertothose inthe image
Steady, followerandother rests
A steadyrest
Grindingmachine
From Wikipedia,the free encyclopedia
Thisarticle includesalistof references,relatedreadingorexternal links,butitssourcesremain
unclear because it lacks inline citations.Please improvethisarticle byintroducingmore precise
citations. (April2009)

9. Rotatingabrasive wheel onabenchgrinder.
A grindingmachine, oftenshortenedto grinder,isany of various powertools ormachine tools usedfor
grinding,whichisatype of machiningusingan abrasive wheelasthe cuttingtool.Each grainof abrasive
on the wheel'ssurface cutsa small chipfromthe workpiece viasheardeformation.
Grindingisusedto finishworkpiecesthatmustshow highsurface quality(e.g.,low surface roughness)
and high accuracy of shape anddimension.Asthe accuracyindimensionsingrindingisonthe orderof
0.000025 mm, inmostapplicationsittendstobe a finishingoperationandremovescomparativelylittle
metal,about0.25 to 0.50 mm depth.However,there are some roughingapplicationsinwhichgrinding

10. removeshighv
Hacksaw
From Wikipedia,the free encyclopedia
Typical full-size hacksawframe,with12"blade
A hacksaw is a fine-toothedsaw,originallyandprincipallyforcutting metal.Theycanalsocut various
othermaterials,suchasplasticand wood;forexample, plumbers andelectricians oftencutplasticpipe
and plasticconduit withthem.There are handsaw versionsandpoweredversions(powerhacksaws).
Most hacksawsare handsaws witha C-shapedframe thatholdsablade undertension.Suchhacksaws

11. have a handle,usuallyapistol grip,withpinsforattachinganarrow disposable blade.The framesmay
alsobe adjustable toaccommodate bladesof differentsizes.A screw orothermechanismisusedtoput
the thinblade undertension. Panel hacksawsforgothe frame and insteadhave a sheetmetal body;
theycan cut intoa sheetmetal panel furtherthana frame wouldallow.These sawsare nolonger
commonlyavailable,buthacksawblade holdersenable standardhacksaw bladestobe usedsimilarlyto
a keyhole saworpad saw.Powertoolsincludingnibblers,jigsaws,andangle grindersfittedwithmetal-
cuttingbladesanddiscsare nowusedfor longercutsinsheetmetals.
On hacksaws,aswithmost frame saws,the blade can be mountedwiththe teethfacingtowardoraway
fromthe handle,resultingincuttingactiononeitherthe pushorpull stroke.Innormal use,cutting
verticallydownwardswithworkheldinabenchvice,hacksaw bladesshouldbe settobe facing
forwards.Some frame saws,includingFretSawsandPiercingSaws,have theirbladessettobe facingthe
handle because theyare usedtocut by beingpulleddownagainstahorizontal surface.
Blades
Juniorhacksaw
Bladesare available instandardizedlengths,usually10or 12 inchesfora standardhandhacksaw.
"Junior"hacksawsare typically150mm long.Poweredhacksawsmayuse large bladesinarange of sizes,
or small machinesmay use the same handblades.
The pitch of the teethcan be anywhere fromfourteentothirty-twoteethperinch(tpi) forahand blade,
withas fewas three tpi fora large powerhacksaw blade.The blade chosenisbasedonthe thicknessof
the material beingcut,witha minimumof three teethinthe material.Ashacksaw teethare sosmall,
theyare setina "wave"set.Asforothersaws theyare set fromside toside to provide a kerf or
clearance whensawing,butthe setof a hacksaw changesgraduallyfromtoothtotooth ina smooth
curve,ratherthan alternate teethsetleftandright.
Hacksaw bladesare normallyquite brittle,socare needstobe takento prevent brittle fracture of the
blade.Earlybladeswere of carbonsteel,now termed'low alloy'blades,andwere relativelysoftand
flexible.Theyavoidedbreakage,butalsowore outrapidly.Exceptwhere costisa particularconcern,this
type isnow obsolete.'Lowalloy'bladesare still the onlytype available for the Juniorhacksaw,which
limitsthe usefulnessof thisotherwise popularsaw.
Hacksaw blade specifications:The mostcommon blade isthe 12 inchor 300 mm length.Hacksaw
bladeshave twoholesnearthe endsformountingtheminthe saw frame and the 12 inch / 300 mm
dimensionreferstothe centertocenterdistance betweenthese mountingholes.[3]
12 Inch Blade

12. Hole to Hole:11 7/8 inches/300 mm
Overall blade length:12 3/8 inches/ 315 mm (nottightlycontrolled)
MountingHole diameter:9/64 to 5/32 inch/ 3.5 to 4 mm (nottightlycontrolled)
Blade Width:7/16 to 33/64 inch/ 11 to 13 mm (nottightlycontrolled)
Blade Thickness:0.020 to 0.027 inches/0.5 to 0.70 mm(varieswithtoothpitchandother
factors)
The kerf producedby the bladesissomewhatwiderthanthe blade thicknessdue tothe setof the teeth.
It commonlyvariesbetween0.030and 0.063 inches/0.75 and1.6 mm dependingonthe pitchandset
of the teeth.
The 10 inch blade is alsofairlycommonandall the above dimensionsapplyexceptforthe following:
Hole to Hole:9 7/8 inches/ 250 mm
Overall blade length:10 3/8 inches/ 265 mm (nottightlycontrolled)