AMT–100Aircra,Material,Processes&

HardwareChapter5

MetalProper<es•  Hardness-Thepropertyofamaterialthatenablesittoresistpenetra<on,wearorcuDngac<ons.

•  Strength–Theabilityofamaterialtoresistdeforma<on(beingdeformed)

•  Malleability-Thecharacteris<cofamaterialthatallowsittobestretchedorshapebybea<ngofahammerorpassingthroughrollerswithoutbreaking.

MetalProper<es•  Duc<lity-Thepropertywhichallowsmetaltobepermanentlydrawn,bent,ortwistedintovariousshapeswithoutbreaking.

•  Elas<city-Thecapabilityofamaterialtobestretched(deforma<on)andtorecoverit'ssizeandshapea,erit'sdeforma<on.Thepointatwhichpermanentdeforma<onoccursistheyieldpoint.

•  Toughness-Thepropertyofthemetalwhichallowsittobedeformedwithoutbreaking.TheoppositeofbriPleness.

MetalProper<es•  BriPleness-Thepropertyofamaterialtobreakwhenbentordeformed.Itistheresistancetochangeintherela<veposi<onofthemoleculesinthematerial.

•  Conduc<vity-Theabilityofamaterialtotransferheatorelectricity

•  ThermalExpansion–Thecontrac<onandexpansionofmaterialastheresultofhea<ngorcooling.

FerrousMetals•  Ferrousmetalisonethatcontainsiron•  Pureironistooso,foraircra,use

!  Addcarbontoironandyougetsteel

•  SAE-SocietyofAutomo<veEngineers

•  SAEfour-digitnumberingsystemforiden<fyingsteel!  Firstdigit:basicalloyingelement

!  Seconddigit:thepercentageofthebasicelementinthealloy

!  Thirdandfourthdigits:percentageofcarboninthealloyin1/100ofapercent

FerrousMetals•  Example:SAE1020-steelthatislow-carbonsteelthatcontains0.20%carbon

•  Maximumamountofcarbonisjustover1%!  Morecarbon,harderandmorebriPle

•  1XXX–Carbonsteel!  SAE1010to1030

•  0.10to0.30%carbon•  So,•  Canbesurfacehardened

FerrousMetals•  1XXX–Carbonsteel

!  SAE1030to1050–medium-carbonsteels

!  SA1050andgreater–high-carbonsteel

•  2XXX–Nickel!  SAE2330steelisusedforaircra,bolts,cableterminals,keys,clevises,andpins.

•  3xxx-Nickel-chromiumsteel

FerrousMetals•  41xx-Chrome-molybdenumsteel

!  4130verycommoninaircra,parts

•  6xxxChrome-vanadiumsteel!  Commonfortools

CRES•  CorrosionResistantsteel•  Stainlesssteel•  10+%ofchromium

•  200thru400series•  Usuallynon-magne<c

AluminumAlloys•  Aluminumalloyfour-digitiden<fica<onsystem:

!  Firstdigit-Alloytype

!  Seconddigit-Modifica<onofalloy!  Thirdandfourthdigits-Purityofaluminum

•  1100–purealuminum

•  2XXX–Copperischiefalloy!  Strongbutcorrodeseasily!  2117–rivets,2024–sheetmetal!  Can’tweld

AluminumAlloys•  Cladaluminum(Alcad)–averythinlayerofpurealuminumappliedtothesurfaceofsheetaluminum!  Protectagainstcorrosion

•  Purealuminumcreatesaluminumoxidewhenexposed•  Aluminumoxideisawhitefilm

•  Protectstheremainingaluminum•  Isaninsulator

!  Easytoscratch!  Slightlylessstrengththananuncladsheetofthesamethickness

MagnesiumAlloys•  Light&Strong•  Highlysuscep<bletocorrosion•  Tendencytocrack•  Burns

!  Usedry-powderfireex<nguisher!  Don’tusewater

Titanium•  Highstrength•  Corrosionresistant•  Lightweight•  Needspecialtoolstowork,machineorweld

PureCopper•  Goodconduc<vity–heatandelectricity•  Corrosionresistant•  BecomesbriPlewhenworkhardened

•  Alloys!  Beryllium!  Zinc–makesbrass!  Tin–makesbronze

!  Aluminum!  Manganese

Nickel•  Usedforhighstrengthandhightemperatureapplica<ons

•  Monel

•  Inconel

IronCrystallineForm

IronCrystallineForm

MetalHeatTreatment•  Steelhasacrystallinestructure•  Thearrangementofatomsinsteel’scrystallinestructuredeterminethesteel’shardness

•  Theprocessesofhea<ngandcoolingareusedtocontrolnatureofthestructure

•  Thesamehea<ngandcoolingprocessescanbeusedtocontrolhowthealloyingelementschangethesteel’sstructure

MetalHeatTreatment•  Cri<calTemperature–Thetemperatureatwhichtheinternalstructuretakesacrystallineform!  Lowerthanmel<ngpoint

•  Tocontrolthesteel’shardness,thesteelisraisedtoabovethecri<caltemperatureandthancooledtolockinthecrystallinestructure

•  Thefasterthesteeliscooled!  Themoredensethecrystallinestructure!  Themorehard(harder)

!  ThemorebriPle

MetalHeatTreatment•  Thecoolingprocessiscallquenching•  Quenchingliquidsandrates

!  Brine(water&salt)–veryfast

!  Water–fast!  Oil–slow

•  Canstartaflashfire!  Polymerandwater–precisioncontrol!  Salts–precisioncontrol

•  Producesmoreconsistentresultsbetweeninteriorandsurface

•  Highspeedquenchingcancausecracking

MetalHeatTreatment•  Normalizing

!  Forging,working,rolling,machiningandweldingcanleavestressesinametalstructure

!  Normalizingrelievesthestresses

!  Heattoabovecri<caltemperatureandthencooledslowlyinair

MetalHeatTreatment•  Annealing

!  Producesafine-grain,so,,duc<lemetalwithoutinternalstressesorstrains

!  Canproducetheloweststrengthsteel

!  Heatabovecri<caltemperatureandletitsit(soakatthattemperature

!  Slowlycooledinatemperaturecontrolledfurnace

SteelTemperatureRanges

Temperaturerangesforheattrea<ngsteelalloys.

MetalHeatTreatment•  Tempering-AformofheattreatmentinwhichsomeofthehardnessandbriPlenessisremovedfromametalthathasbeenhardenedbyheattreatment!  Temperingtemperaturesarelowerthanthecri<caltemperature

!  Temperingproceduresincludeaspecifictemperatureand<me

MetalHeatTreatment

Temperingtemperaturesforvarioussteelalloystoobtaintheindicatedtensilestrength.

ToolTempering

Temperingofsmalltoolsbyobservingthecoloroftheoxidesthatformwhenthesteelisheated.

CaseHardening•  Casehardening-AtypeofmetalheattreatmentinwhichthesurfaceofthemetalishardenedandmadebriPlewhilethecoreofthematerialremainsstrongandtough!  Usuallydonewithlowercarbonsteel!  Thehardenshellisverythin

•  0.01”to0.06”!  Thehardeningprocesscanbeappliedtoonlyspecificpartsofanobject

CaseHardening•  Nitriding-Amethodofcasehardeningsteelbyhea<ngitinanatmosphereofammonia.Thenitrogenintheammoniareactswiththesurfaceofthesteeltoformextremelyhardnitrides!  Doesn’tchangethedimensionofthepart!  Causeslessdistor<onthanothertypesofcasehardening

CaseHardening•  Carburizing-Casehardeningprocessinwhichaddi<onalcarbonisinfusedintothesurfaceofalow-carbonsteel.!  Surfaceisheatedandthenexposedtocarbon

!  CarboncancomefromCO2,sootorcoke!  CanbemadeinafurnacefilledwithCO2

ColdWorking•  Plas<cDeforma<on-Amaterialundergoingnon-reversiblechangesofshapeinresponsetoappliedforces

•  ColdWorking-Thestrengtheningofametalbyplas<cdeforma<onatlowtemperatures!  Alsocalledworkhardeningorstrainhardening!  Coldrollingisaformofcoldworking

•  Wrought-beatenoutorshapedbyhammering

Forging•  Forging–Theprocessbywhichmetalisheatedandisshapedbyplas<cdeforma<onbysuitableapplyingcompressiveforce!  Usuallydonewithpowerhammerorpress

!  Refinescrystalgrainstructure•  Improvesstrength,duc<lityandtoughness•  Canorientdirec<onofgrainflowtothatoftheprinciplestressesencounteredinactualuse

•  Video1•  Video2•  Video3

Cas<ng•  Cas<ng–formingbymel<ngthemetalandpouringintoamoldofthedesiredshape

•  Video1,Video2•  Lesscontrolovergrainandcoolingprocess•  LowerstrengthandmorebriPlethanforgedproducts

Extrusion•  Extrusion–forcingametalthroughanopeninginadie,thuscausingthemetaltotaketheshapeofthedie

•  Video

HeatTrea<ngAluminumAlloys•  CalledSolu<onHeatTrea<ng•  Mustbequenchedimmediatelyinwater

!  Createssmallcrystals•  ThesmallerthecrystalsthebePer•  Quenchasfastaspossible

!  Delayinquenchingcausesthecrea<onoflargercrystals•  Largercrystalscauseintergranularcorrosion

!  Intergranularcorrosion-Corrosionthatformsalongthegrainboundariesinapieceofmetal.

IntergranularCorrosion

Intergranularcorrosioncanstartonthesurfaceandprogressthroughthemetal,followingthegrainboundaries.

IntergranularCorrosion

IntergranularCorrosion

HeatTrea<ngAluminumAlloys•  Aluminumdoesn’treachfullstrengthimmediatelya,erquenching

•  Thealuminumhardenswithage!  Called“aging”or“agehardening”!  Canhappeninminutes,hours,daysoryears

!  Remember“icebox”rivets(D&DD)

Ar<ficiallyAgeHardeningAluminum•  CalledPrecipita<onHeatTreatment•  Acceleratetheprocessofagehardening•  Heldatatemperature,muchlowerthanthatusedforsolu<onheattreatment,forupto24hoursandthenremovedfromtheovenandallowedtocooledins<llair

•  Increasesthestrengthandhardness•  Reducesduc<lity•  Makeshardertobendandform

AluminumTreatment•  Annealingisusedtoso,enaluminum

!  Usedtoso,enaluminumwhenworkingor“pounding”metalintoshape

•  AluminumisNOTnormalized!  Onlysteel

•  Onceclad,sheetmetalisnotheattreated!  Thepurealuminumlayerwillcontaminateinnerlayer

AluminumAlloyTemperDesigna<ons•  Temper-hardened•  F–Fresh/rawaluminum

!  Nevercoldworked,heattreated,orannealed

•  O–Annealed•  T–Heattreated/hardened•  H–Work/strainharden

AluminumAlloyTemperDesigna<ons

Temperdesigna<onsofaluminumalloys.

HardnessTes<ng•  Twomethods:

!  Rockwell

!  Brinell

•  Rockwell!  Measuresthehardnessofametalbymeasuringthedepthofpenetra<onofaspecialpenetratorunderaspecifiedload

!  So,metalsuseahardenedsteelball!  Hardmetalsuseadiamondcone!  Fourscales:AthruD

•  BandCthemostcommon

RockwellTes<ng

RockwellTes<ng•  Video

BrinellHardnessTes<ng•  Hardnessofthematerialismeasuredbythediameteroftheimpressionmadebya10-mm-diameterhardenedsteelballforcedintothematerialbyahydrauliccylinder

BrinellHardnessTes<ng

A.Brinellhardnesstester.B. MicroscopicviewofimpressionmadebyaBrinelltester.

Figure 7-9.

Wood•  Onceaverypopularmaterial•  Lightandstrong•  Hasproblemswithwaterdecay

•  Becarefulwhichglueisusedforrepair!  Theglueusedtomanufacturetheaircra,maynolongerbeacceptable

!  AC43-1BrecommendsResorcinoladhesive(resorcinol-formaldehyderesin)

!  AC43-1Balsorecommendsepoxybutdoesn’tindicatewhichone

Plas<cs•  Thermoplas<cresins

!  So,enedbyheatandhardenedwhencooled

!  Usedforwindshieldsandsidewindows!  Celluloseacetate

•  Yellowswithage•  Dissolveswithacetone

!  Acrylicresins•  Tradename-Plexiglas,Lucite,andPerspex

Plas<cs•  ThermoseDngResins

!  Willnotso,enwhenitisheated,anditwillcharandburnbeforeitmelts

!  Plas<ctrim

!  Epoxy

Fabric•  CoPon

!  Decayseasily

!  Usedforrestora<onprojects

•  PolyesterhasreplacedcoPon!  TradenameDacronorCeconite

•  Severalcoveringsystemsavailabletoreplacenitrate/butyrate(dope)!  NeedanSTCtoapply

Composites•  Fabricsheldtogetherwithglue

!  Strengthprovidedbyfabricnotglue•  Usetheminimumamountofglue

•  Glues!  Epoxy

•  Twopartresins•  Mixra<oiscri<cal

!  Polyesters•  Mixwithacatalyst

•  Mixra<oislesscri<cal•  Notasstrongepoxy

Composites•  Fabrics

!  Fiberglass•  Strongandlight•  Non-conduc<ve•  Rela<velyinexpensive

!  Kevlar•  Strongandstretches•  Non-conduc<ve

Composites•  Fabrics

!  Carbon•  Verystrong

!  Strongerthanfiberglass

•  Conduc<ve!  Radioinstalla<onmoredifficult

•  Cancausecorrosionproblemswithmetals

•  CanbebriPle•  Expensive

•  Theindustryiss<lldevelopingmethodstorepairdamage

•  Agingproper<esares<llunknown

Rubber•  Natural–fromtrees•  Synthe<c•  Notallrubbersareequal

!  Matchtherubbertotheapplica<on!  RTFM

Aircra,Hardware•  AsanA&P,youmustinsurethatanaircra,containsonlythehardwarespecifiedbythetheaircra,manufacturer

•  Na<onalhardwarestandards!  AN–AirForce-Navy

!  MS-MilitaryStandard!  NAS-Na<onalAerospaceStandards

ThreadFit•  Standards

!  UnifiedStandard–3classes•  A–screworexternalthread•  B–nutsorinternalthread

!  American(Na<onal)Standard–4classes•  Class-1-fitisaloosefit.Usedforeasytoremoveapplica<on

•  Class-2-fitisafreefit.Itisusedforsomemachinescrews.•  Class-3-fitisamediumfit.Itisusedforalmostallstandardaircra,bolts.

•  Class-4fitisaclosefit,thatrequiresawrenchtoturnthenutontothebolt.

FastenerTorque•  Followthemanufacturer’srecommenda<ons

!  OrAC43-13-1BTable7-1

•  Unlessotherwisespecified,torquevaluesfor<ghteningaircra,fastenersarespecifiedwiththreadsingoodcondi<onandtheymustbecleananddry!  Iflubrica<onisspecified,usetheexactlubrica<oncalledforandtheexactamount

FastenerTorque•  Methods:

!  Torquewrench•  Remembertoaddthetorquerequiredtoturnaloosefastener

!  Nut-rota<onmethod•  Tightenedun<lfastenerissnug,thenturnedaspecificnumberofturnsor“faces”

!  Bolt-stretchmethod•  Tightenedun<lthefastenerisstretchedaspecifiedamount

TorqueRa<os•  1in-oz=28.35gram-in•  1in-lbs=16in-oz•  1foot-lbs=12in-lbs

Aircra,BoltIden<fica<on

Aircra,boltiden<fica<on.

BoltMarkings•  Crossorasterisk-nickelsteel•  Singledash-corrosion-resistantsteel(CRES)bolt•  Twodashes-aluminumalloy

•  Trianglesurroundingthecrossorasterisk-close-tolerancebolt!  Hasnogripcoa<ng

Bolt Length

Shank

Chamfer

AN3thruAN20•  Hexheadboltfortensionorshear•  Grip–por<onwithnothread

!  Shouldbethesamelengthasthethicknessofthematerialbeingfastenedwiththebolt

•  Shank–Includesthethreadedpor<on•  Chamfer-taperedend

•  Length-boPomoftheheadtothechamfer

•  Finethread–UNF-3A•  NewstandardisNASM3thruNASM20

AN3thruAN20•  Example:AN4H6

!  StandardBolt

!  AN4–1/4”diameter!  H-steelwithholeinhead!  6–3/4”long

!  NoA-holeinshank

AN3thruAN20•  AN(Diameter)(Material)(HeadHole)(Length)(ShankHole)

•  AN•  Diameter-3thru20-in1/16’s-3/16through11/4(20/16)

•  Material!  “-”NickelSteel2330(SilverisCadmium1,GoldisCadmium2)

!  “C”–CRES

!  “DD”–Aluminum

•  H-holeinhead

AN3thruAN20•  Lengthin1/8’s

!  3thru7–3/8thru7/8

!  No8or9!  1”andabove–firstdigit–inches,second–1/8’s

•  'A'isnoshankhole,Nothingisholeinshank

AN3thruAN20•  Example:AN4H6

!  StandardBolt

!  AN4–4/16”-1/4”diameter!  H-steelwithholeinhead!  6–6/8”-¾”long

!  NoA-holeinshank

•  TestExamples:!  AN5-7!  AN14C7A

!  AN16H10!  AN7DD7A

BoltInstalla<on•  Whenpossible

!  Installheadfacingforward orInstallheadfacingup

!  Lesslikelytofallout

•  AN3isreallyaNO.10-32screwsize!  Biggerthan3/16”

BoltInstalla<on–AC43-13-1B•  Overtheyears,somefastenersspecifica<onshavebeenchanged.Forthisreason,itisrecommendedwhenmakingrepairstoanaircra,,whoseoriginalhardwareisbeingreplaced,thatyoumustfirstmeasuretheboltbeforeordering,ratherthanrelyingonthepartsmanualforiden<fica<on.

•  Themaximumcombinedheightofwashersthatshouldbeusedis1/8inch.Thislimitstheuseofwashersnecessarytocompensateforgrip,uptothenextstandardgripsize.

BoltInstalla<on–AC43-13-1B•  Allboltinstalla<onswhichinvolveself-lockingorplainnutsshouldhaveatleastonethreadoftheboltprotrudingthroughthenut.

•  Lockorsafetyallboltsand/ornuts,exceptself-lockingnuts.DonotreusecoPerpinsorsafetywire.

ClevisBolt

Aclevisboltisdesignedtotakeshearloadsonly,andshouldneverbeusedwhereatensileloadisimposed.

AN21thruAN37•  Clevisbolt•  Forshearloadsonly•  Normallyinstalledsothattheyarelooseandfreetorotate

•  Whenrota<onispossible,ashearcastlenutshouldbeinstalledandacoPerpinshouldbeusedtosecurethenuttothebolt.

•  Whenaclevisboltisusedtosecureafork-endcableterminal,thenutshouldbe<ghtenedun<litissnug,buttheremustbenostrainonthefork.

AN21thruAN37•  Steelonly•  Usesiden<fiernumbersimilartoAN3thruAN20

•  Diameter!  AN21–NO.6-40screwsize!  AN22–NO.8-32screwsize!  AN23–NO.10-32screwsize

!  NoAN36,AN37is1¾”long!  AN24thru35

•  (AN#-20)X1/16!  e.g.AN24–(24–20)X1/16=4/16=1/4"

AN21thruAN37•  Materialisalways“-”

!  Steel

•  Lengthin1/16”!  Nospecialdesigna<onforover15/16”

•  Add'A'totheendfornoshankhole.Nothingisholeinshank

DrilledHeadBolts•  AN73thruAN81–DrilledHeadBolts

!  Threadtype&material•  “-”–Steelwithfinethread•  “A-”–Steelwithcoarsethread

!  Diameterin1/16”•  AN#-70

!  e.g.AN75–70=5/16

!  Lengthis1/8”•  Doubledigitlikestandardbolts

!  Noshankholeandno“A”used

DrilledHeadBolts•  AN73thruAN81–DrilledHeadBolts

!  e.g.AN75-10is5/16”diameter,steel,finethread&1”long

!  e.g.AN75A-10is5/16”diameter,steel,coarsethread&1”long

DrilledHeadBolts•  SupersededbyNASM20073&NASM20074

!  NASM20073issteelwithfinethread

!  NASM20074issteelwithcoarsethread!  Bothuse–dd-llforsizing

•  ddistwodigitdiameterin1/16”

•  llistwodigitlengthin1/8”-likestandardbolts!  e.g.NASM20073-05-10issteel,finethread,5/16”diameter&11/4”(10/8)long

!  e.g.NASM20074-05-10issteel,coarsethread,5/16”diameter&11/4”(10/8)long

DrilledHeadBolts•  Finethreadfornutsorsteelparts•  Coarsethreadforaluminumormagnesiumcas<ngs

CloseToleranceBolts•  AN173thruAN186•  Noexternalcoat

!  Protectedbyoilorgrease

•  Steelonly•  NumberingsystemthesameasAN3thruAN20exceptsubtract170fromAN#!  e.g.AN175–170=5or5/16diameter

•  HeadMarkings–triangle,trianglewithacrossinside,trianglewithasteriskinside

Nuts

Commonlyusednon-self-lockingaircra,nuts.

Nuts•  AN310–CastleNut&AN320–ShearCastleNut

!  NowcalledNASM310&NASM320

!  Material•  “-”–Steel•  D–Aluminum•  C–CRES

!  Diameterin1/16”–finethread!  AN320areusedforshearapplica<onsonly!  TorquetominimumseDng.Ifshankholedoesn’tlineup,torqueuptomaximumseDng•  Changewashersifshankholedoesn’tlineup

Nuts•  AN315–PlainNut

!  NowcalledNASM315

!  Material•  “-”–Steel•  D–Aluminum•  C–CRES

!  Diameterin1/16”–finethread!  “R”isrighthandthread,“L”isle,handthread

•  RmaybeomiPed

!  e.g.AN315-8RorAN315-8

Nuts•  AN316–CheckNut

!  NowcalledNASM316

!  Material•  “-”–Steel•  C–CRES

!  Diameterin1/16”–finethread!  “R”isrighthandthread,“L”isle,handthread

•  RmaybeomiPed

!  e.g.AN316-8RorAN316-8

!  Usetolockothernuts

Nuts•  AN365–SelfLockingNut

!  NowcalledMS20365

!  Material•  “-”–Steel•  D–Aluminum•  B–Brass

!  Diameter&TPI–ddPordP•  dorddisdiameterin1/16”

•  PisTPI(coarsethreadfor#4thru#8screwsizes)•  e.g.624is3/8-24•  Screwsizes440,632,832&1032

Nuts•  AN365–SelfLockingNut

!  Insertmaterial•  A-non-metallic–lowtemperatureapplica<ons•  C–metallic–hightemperatureapplica<on

•  Nodesigna<on–EitheranAorCcanbeused!  Theinserthasasec<onthathasnothreads,thisiswhatlocksthebolt

!  Selflockingnutsshouldnotbeusedwithfastenersthatrotate

!  Ifyoucanturnaselflockingnutwithyourhand,itiswornout.

Nuts•  AN363(MS20363)–Hightemperatureselflocking

•  AN364(MS20364)–Thin(shear)selflocking

•  AN356(MS27151)–PalNut!  Nutmadeoutofpressedsheetmetal!  TrademarkPalnut™

!  AN356andMS27151isdifferentnumberingsystem

Nuts•  AN350–Wingnuts•  MS21078,MS21080,MS21081areluganchornut

•  MS21079isachannelnut

TinnermanSpeedNut

PlainWashers•  AN960–Plainwasher

!  NowcalledNAS1149

•  AN970-PlainWasherLargeArea!  NowcalledNASM970

•  Availableinavarietyofmaterialsandcoa<ng!  Usecorrectmaterialandcoa<ngpreventcorrosionproblems

•  Availableisstandardandlight(thin)thicknesses!  Lightwashercanbeusedtoadjustcastlenutposi<on

PlainWashers•  Providesasmoothbearingsurface•  Protectssurfacefromgalling&corrosion

!  Mustbeusedwhenusingalockingwashers

•  Shouldbeusedundereveryboltheadandnut•  Whenusinglockwasher,theordershouldbe:

!  Ma<ngsurface!  Plainwasher

!  Lockwasher!  Nut

LockWashers

LockWashers•  AN935–Splitlockingwasher

!  NowcalledMS35338

!  Steel!  AN935hasdifferentthicknesses,MS35338doesn’t

•  AN936–Starwasher!  TypeA–internalteeth

!  TypeB–externalteeth!  Availableinsteelandbronze!  Singleuse

WhenNottouseaLockWasher•  Withfastenerstoprimaryorsecondarystructure•  Withfastenersonanypartoftheaircra,wherefailuremightresultindamageordangertotheaircra,orpersonnel

•  Wherefailurewouldpermittheopeningofajointtotheairflow.

•  Wherethescrewissubjecttofrequentremoval

WhenNottouseaLockWasher•  Wherethewashersareexposedtotheairflow•  Wherethewashersaresubjecttocorrosivecondi<ons

•  Theaboverulesaregoodguidelineswhennottouselocknuts

CoPerPins•  AN380–SteelcoPerpin•  AN381–CREScoPerpin•  NowcalledMS24665

•  Checkdatasheetfordashnumberingsystem

•  Diametershouldbethelargestsizetofitintofastener’shole

•  Topreventinjuryduringanda,erpininstalla<on,theendofthecoPerpincanberolledandtucked.

CoPerPins•  Don’treusecoPerpins•  Don’tuseautomo<veorhardwarestorecoPerpins

CoPerPins–43.13-1B

Screws•  Types:

!  Structural

!  Machinescrews!  Self-tapping

•  Structuralscrew!  Muchlikestandardboltbutwithscrewhead

!  Fineandcoarsethread

•  Machinescrews!  Usuallynogrip!  Steel,CRESorbrass

!  Nousedforprimarystructure

Screws•  Countersunk/flatheadmachinedandstructuralscrewuse100°countersink

•  Fillisterheadscrewsmayhaveasafetywirehole

ScrewHeads

FillisterHead

ScrewHeads

ScrewHeads

WasherHeadScrews

SelfTappingScrews•  AlsocalledPKorParkerKalonscrews•  82°countersunk•  Usedforsheetmetalandinspec<onpanel

•  UsedwithTinnermannuts

•  Non-structural

SelfTappingScrews

DzusFastener

Dzus™Fastener

Dzus™Fastener

Dzus™Fastener

Dzus™Fastener•  Lengthspecifiedin1/100(0.01)inchincrements•  Diameterspecifiedin1/16inchincrements

•  Headmarkingsarebodydiameter,typeofhead,andlengthofthefastener

•  Reten<ongrommet/collarcommonlycomeloose

CamLockFastener

CamlockFastener

Camlockfastener:explodedview.

AirlocFastener

BlindRivets•  Canbeinstallfromoneside

!  Installedwith“puller”tool

•  PopRivet!  Poprivetinstalla<on!  Usedforno-structuralworkonly!  Hollowa,erinstalla<on

BlindRivets•  “CherryRivets”

!  Notyourhardwarestorerivets

!  Widevariety–CherryLock,CherryMax,Huck-Clinch,HuckMax,Olympic-Loc

!  CherryMaxAnima<on!  CherryMaxcanreplaceasolidrivetofthesamesizediameter•  Somemechanicsareconcernedabouttherivetsvibra<ngloose

!  InstallCherryMaxRivet

!  Hardtoremove•  Airframebook(FAA-H-8083-31)page4-49

CherryRivetRemoval

Hi-Shear™

Hi-Shear™

Hi-Shear™

Hi-Lok™•  Installa<onVideo•  Canbeinstalledwithstandardtools

HuckLockbolt™

HuckLockbolt™

HuckLockbolt™

More grooves for tension version

Rivnut™

Good for thin sheet metal applications

Rivnut™

CherryRivetlessNutplate•  Installa<onanima<on

Aircra,ControlCable

Aircra,ControlCable

Aircra,ControlCable

CablePulley

CableFairleads

Aircra,ControlCable•  CableMaterial

!  CRES

!  Galvanizedsteel•  Olderstyle

•  Typesofcable:!  Nonflexible!  Flexible!  Extraflexible

Aircra,ControlCable

Aircra,ControlCable•  CableSize:

!  1/32”through1/2”

!  Primarycontrolcablesmustbe1/8”orlarger!  Trimtabactuatorcablescanbelessthan1/8”

•  Nonflexiblecable!  1X7–7individualwires

!  1X19–19individualwires!  Forstraightrunsonly!  Can’tpassoverapulley

Aircra,ControlCable•  FlexibleCable

!  Core•  Centersec<on•  7wires•  Straight

!  Outerstrands•  6strands•  Eachstrandhas7wires•  Spiraledaroundthecore

!  Call7X7•  7strands/corewith7wireseach

Aircra,ControlCable•  FlexibleCable

!  Usedforenginecontrolsortrimtabcontrols

!  Canbeusedwithapulley

•  Extra-flexibleCable!  7standswith19wireseach!  Cableispreformed

• Willnotspringoutwhencut

!  Usedforprimaryflightcontrols

•  Cablesareinspectedforbrokenwiresbyrunningaclothalongthecable!  Abrokenwirewillsnagthecloth

ControlCableTerminals

ControlCableTerminals

A.AN664Singleshankballend.B. AN663Doubleshankballend.C. AN666Threadedcableterminal.D.AN667Forkendcableterminal.E. AN668Eyeendcableterminal.

Aircra,ControlCable

ControlCableTerminals•  Terminalsareswagedon

!  Squeezedontothecable

•  Swagedconnec<onis100%(full)ofcablestrength

•  Cablesaretestwitha“go-no-go”gage!  Theterminalmustbe“squeezed”enoughtofitthroughthegage

•  Aspotofpaintisappliedtocable/terminalseamtoprovideaninspec<onmark!  Ifthepaintisdamaged,thecablehasslipped

•  Replacethecable

SwageTools

TerminalGage

A.  Gagingaswaged-oncontrolcableterminaltodeterminethatithasbeenproperlyswaged.

B. Typicalterminalgage.

Nicopress

A.Installa<onofNicopress-typesleevesonacontrolcable.B. TypicalNicopressgage.

Nicopress

Nicopress•  Cableiswrappedaroundasteelthimble•  Acoppersleeveisswagedoverthecable

!  Threecrimps•  First-center•  Second–nexttothimble

•  Third–farend!  100%ofcablestrength

•  Testedwitha“go-no-go”gauge

Turnbuckles

Turnbuckles•  Onesideisthreadedle,andothersideisthreadedright!  Turningthebarrelwilleitherlengthenorshortentheturnbuckle

•  Nomorethanthreethreadscanbeexposedoneitherendofthebarrel

•  Onini<alinstalla<on,theturnbuckleterminalsshouldnotbescrewedinsidetheturnbucklebarrelmorethanfourthreads

•  SafetyaccordingtoAC43-13-1B

Turnbuckles

SafetyWire•  AC43.13-1B

!  Chapter7-Sec<on7•  Safetying

!  Chapter7–Sec<on10•  SafetyMethodsforTurnbuckles

SafetyWire•  Usedtosecure:

!  Drilledheadboltheadsandscrews

!  Valvehandles!  Electricaltwist-onconnectors!  Oilfilters

!  Emergency&oxygenhandles!  Turnbuckles

•  Whenacastlenutisinstalledonastudthatisscrewedintoacas<ng,itshouldbesafe<edwithsafetywire.

SafetyWire•  Materials:

!  Usuallystainlesssteel

!  Copper/brass–usedforemergency“breakaway”applica<ons

SafetyWire•  Methods

!  Doubletwist•  Nomorethan3fasteners

!  Singlewire•  Closelyspacedorclosed-geometricalpaPernsuchasatriangle,square,rectangle,orcircle

•  Nomorethan24”long

SafetyWire–DoubleTwist

SafetyWire–SingleWire

SafetyWire

SafetyWire

SafetyWire•  DoubleTwistSize

!  0.032”diameterwireshouldbeusedonpartsthathaveaholediameterlargerthan.045”

!  0.020“maybeusedonpartshavinganominalholediameterbetween.045and.062”withaspacingbetweenpartsoflessthan2”

•  SingleWireSize!  Largestsizewirethattheholewillaccommodate

•  Followthemanufacturer’srecommenda<ons

SafetyWire

Therecommendednumberoftwistsperinchisdeterminedbythediameterofthesafetywire.

6 to 8 twists per inch is typical

SafetyWire•  Safetywiremustbeinstalledinamannerthatwillpreventthetendencyoftheparttoloosen.!  Lookslikeinbackwards“S”

•  Cleanupsafetywire!  Cleanupinstalla<onscraps

!  Becarefulwhenremovingwire

•  Don’treusewire•  Don’tunwireandreinstalls•  Don’tknickwire

SafetyWire•  Reinstallifindoubt•  Alwayscurltheendtopreventexposuretosharpends

•  4to6twistsontheend•  Outsidewireshouldgoaroundhead

!  Iflimitedspace,outsidewirecangooverthetop

•  AC43-13-1Bisthebestreference!  FollowtheAC’sinstalla<onexamples

SafetyWire–Method•  Twobolt–AC43-1B

!  Outsidewire–clockwisearoundfirsthead

!  Headonetotwo–twistclockwise!  Outerwire–counter-clockwisearoundsecondhead!  Twistendcounter-clockwise

!  Curlend

SafetyWire•  Threebolt–AC43-1B

!  Outsidewire–clockwisearoundfirsthead

!  Headonetotwo–twistclockwise!  Outerwire–counter-clockwisearoundsecondhead!  Headtwotothree–twistcounter-clockwise

!  Outerwire–counter-clockwisearoundthirdhead!  Twistendcounter-clockwise!  Curlend

SafetyWire•  Threebolt–alternatemethod

!  Outsidewire–clockwisearoundfirsthead

!  Headonetotwo–twistclockwise!  Outerwire–counter-clockwisearoundsecondhead!  Headtwotothree–twistcounter-clockwise

!  Outerwire–clockwisearoundthirdhead!  Twistendclockwise!  Curlend

SafetyWire–Turnbuckles

SafetyWire–Turnbuckles•  Doublewrapmethodspreferred•  Endsmusthaveaminimumof4turns

•  FollowthemethodsshowninAC43-13-1BFigure7-26