>> P.13-11
MicrometerHeadsKeyFactorsinSelectionKeyfactorsinselectingamicrometerheadarethemeasuringrange,spindleface,stem,graduations,thimblediameter,etc.themicrometerSelectyourparticularcharacteristics.referringpurposesuitsbythatbesttoitsStemPlainstemStemlocknuttype■Thestemusedtomountamicrometerheadisclassiedasa"plainistype"or"clampnuttype"asmanufacturedtoanominalMetricorImperialsizewithanh6tolerance.illustratedabove.Thestemdiameter■ Theinstallationsmethodhavethefollowingfeatures:• Clampnutstem:AllowsfastandsecureclampingofthelineargageSpindleThreadPitch■Thestandardtypeheadhasa0.5mmpitch.■1mm-pitchtype:Quickertopositioning,etc.,thanthestandardtypeandavoidsthepossibilityofa0.5mmreadingerror.Excellentload-bearingcharacteristicsduetolargerscrewthread.■0.25mmor0.1mm-pitchtypeThistypeisthebestforne-feedorne-positioningapplications.Constant-forceDevice■Amicrometerheadttedwithaconstant-forcedevice(ratchetorfrictionthimble)isrecommendedformeasurementapplications.■Ifusingamicrometerheadasastop,orwheresavingspaceisapriority,aheadwithoutaratchetisprobablythebestchoice.head.• Plainstem:Widerrangeofapplicationwithpositionaladjustmentintheaxialdirectiononnalinstallation,butrequiresasplit-xtureclampingarrangementoradhesivexing.■General-purposemountingxturesareavailableasoptionalaccessories.MeasuringFacesMicrometerheadwithconstant-forcedeviceMicrometerheadwithoutconstant-forcedevice(noratchet)SpindleClamp■Whenusingamicrometerheadasastopper,problemscausedbylooseningcanbepreventedbyusingamicrometerheadwithaspindleclamp.Thespindleclampalsopreventsthespindlefromchangingpositionwhentheclampisoperated,providingtheuserwithpeaceofmind.MeasuringRange(Stroke)■Whenchoosingameasuringrangeforamicrometerhead,allowanadequatemargininconsiderationoftheexpectedmeasurementstroke.Sixstrokeranges,5mmto50mm,areavailableforstandardmicrometerheads.■Ifalongstrokeofover50mmisrequired,theconcurrentuseofagaugeblockcanextendtheeffectivemeasuringrange.(Fig.D)GaugeblockHead’sstrokeObtainedstroke■Inthisguide,therange(orstrokeend)ofthethimbleisindicatedbyaline.Considerthethimbleasmovingwithintherangeofthedashedstrokeendstothepositionindicatedbythelinewhendesigningthejig.■Ifamicrometerheadisusedasastop,thenaatfacebothonthespindleFig.Dandthefaceitcontactsprovidesdurability.■Anon-rotatingspindletypemicrometerheadoronettedwithanantirotationdeviceonthespindle(Fig.C)canbeusedifatwistingactionontheworkpiecemustbeavoided.FlatfaceSphericalfaceAnti-rotationdevice■Aatmeasuringfaceisoftenspeciedwhereamicrometerheadisusedasameasurementtool.■Whenamicrometerheadisusedasafeeddevice,asphericalfacecanminimizeerrorsduetomisalignment(Fig.A).Alternatively,theatfaceandsphericalfacecanbereversedsothatthespindlecanbearagainstasphere,suchasacarbideball(Fig.B).MicrometerHeadsFig.AFig.BFig.CNon-RotatingSpindleAnon-rotatingspindletypeheaddoesnotexertatwistingactiononaworkpiece,whichmaybeanimportantfactorinsomeapplications.13-11
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