螺丝头型及垫圈种类(英文版)

FastenerBasicsCommonFastenerTypesFastenerMaterialsHexbolts,orhexcapscrews,areusedinmachineryandconstruction.Canbeusedwithanut,orinatappedhole.Fullythreadedhexboltsarealsoknownastapbolts.Woodscrewshavelargethreadsandasmoothshankforpullingtwopiecesofmaterialtogether.Theycanbeusedinwoodandothersoftmateri-als.Sheetmetalscrewshavesharppointsandthreads,andaredesignedtobedrivendirectlyintosheetmetal.Theycanalsobeusedinsoftermaterialslikeplastic,fiberglass,orwood.Machinescrewsarefullythreadedforusewithanutorinatappedhole.Certaintypesaresome-timesreferredtoasstovebolts.Socketscrewsaremachinescrewswithaninternalhexsocket(Allen)drive.Longerlengthsmayhaveasmoothshank.Lagbolts,orlagscrews,arelargewoodscrewswithhexheads.Typicallyusedforwoodconstructionandlandscaping.Carriageboltshavesmooth,domedheadswithasquaresectionunderneaththatpullsintothematerialtopreventspinningduringinstallation.Nutsareusedtofastenmachinethreadedfastenersinthrough-holeapplications.Locknutshelppreventloosening.Washersspreadtheloadoveragreatersurfaceareawhentighteningabolt,screwornut.Lockwashershelppreventingloosening.Tip:FindamorecomprehensivefastenertypechartGrade/Class&FastenerStrengthFastenerGrade(US)orClass(metric)referstothemechanicalproper-tiesofthefastenermaterial.Generally,ahighernumberindicatesastronger,morehardened(butalsomorebrittle)fastener.Forachartoffastenergrades,headmarkingsandmechanicalproperties,seeBoltDepot’sGrademarkingsandStrengthChartUSboltheadmarkingsMetricboltheadmarkings8.810.912.9LowCarbonGrade5Grade8Class8.8Class10.9Class12.9Note:Inadditiontothesemarkings,theheadwilloftenhaveamanufacturerstamp.Note:Donotrelyonthisguideforcolor-matching.Theappearanceofthesematerialssometimesdierssignifi-cantlyfromthephotosbelow.Zinc-platedsteelisalowcarbonsteelforgeneraluse.Relativelyinexpensive,withthezincplatingprovidingmoderatecorrosionresistancesuitableforindoorsorotherwisedryconditions.Coloriseitherablue-ishtintoryellowdependingontheexactprocess.Hot-dippedgalvanizedsteelhasathickerzinccoatingforbettercorrosionresistance,makingitsuitableforoutdooruse.Becauseofthethickplating,onlygalvanizednutsandwasherswillfitgalvanizedbolts.Thecoatingtypicallyhasarough,dullgreyfinish.Stainlesssteeloersgoodcorrosionresistance,makingitsuitableforoutdooruseandmarineapplications,butismoreexpensivethanzincplated.Chromeandnickelplatedsteelaresmoothandpolishedforappearance.Theplatingoersmoderatecorrosionresistance.Brassandbronzearecopperalloyswithgoodcorrosionresistance.Moreexpensivethansteel,thesematerialsaretypicallyusedfordecorativeapplications.Colorscanvarysignificantly.Alloysteelishighlyhardenedandusuallyblackoxideand/oroilcoated,oeringlittlecorrosionresistance.Page1HowFastenersareNotated:AnExampleMachinescrews,Phillipspanhead,Stainlesssteel18-8,#12-24x1FastenertypeMaterialDiameterLengthThreadCount(TPI)DriveTypesHeadStylesMeasuringDiameterPhillipsSlottedComboFrearsonPozidrivHexsocket(Allen)StarSquare(Robertson)PhillipsandSlotteddrivesarecommoninscrews,butpronetocam-out(stripping).Combodrives,thatcanbeusedwitheitherdriver,areavailableformanyfastenertypes.FrearsonandPozidrivaresimilartoPhillips,butlesspronetocam-out.Hexsocket(Allen)drivesarecompactandeasytodrive,butpronetocam-out.StarandSquaredriveareresistanttocam-outandcanbeinstalledsingle-handed.Hexheadsaretypicallyusedwithlargerboltsandscrews,andtightenedwithawrench.Panheadshaveaslightlydomedheadthatsitsabovethesurface.Flatheadsareinstalledinacountersunkholeforaflatsurface.Roundheadsaretalldomedheads,usedprimarilyfordecorativepurposes.Ovalheadsarealowdomedandcountersunkheads,usedprimarilyfordecorativepurposes.Trussheadsareslightlydomed,withawideheadforanextralargesurfacearea.Socketheadsarenarrowwithasocketdrive,andknurledorsmoothsides.Formosttypesoffasteners,thediameterismeasuredontheoutsideofthethreads.Note:USdiametersunder1/4”aregivenasnumbers(e.g.#12)insteadofinches,inorderofincreasingsize.Ifyouneedtofindtheactualdiameter,useatablecorrespondingtoyourfastenertypeThreadCount&ThreadPitchMachinethreadedfastenersspecifyathreaddensityinThreadsPerInch(US)orasaThreadPitchinmm(Metric).Foragivendiameter,afastenermaybeavailableincoarse(standard),fineandsometimessuperfinethread.MeasuringLengthNote:Mostdrivetypes(FrearsonandSlottedbeingnotableexceptions)requirethecorrectdriversizeforproperinstallation.Buttonheadsfeatureamediumdome.Typicallyusedwithahexsocketdrive.Fastenerlengthisusuallymeasuredfromwherethematerialisassumedtobetotheendofthefastener.Nut&WasherSizesNutandwashersizesindicatethescreworbolttheyfit.Forexample:3/8”-16HexBolt3/8”Washer3/8”-16NutDierentwasherpatternshavedierentoutsidediameters.Forexample,hardenedUSwashersareavailableinUSS(wider)andSAE(narrower)patterns.Fenderwashershavelargeoutsidediameters.1/4”1/4”1/4”x1”SAEUSSFenderPage2Thus,countersunkfastenersaremeasuredoverallandnon-counter-sunkfastenersaremeasuredfromunderthehead..FastenerTypeChartFastenerCategoriesWoodScrewsScrewswithasmoothshankandtaperedpointforuseinwood.AbbreviatedWS.SelfDrillingSMSAsheetmetalscrewwithaselfdrillingpoint.SocketS