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■Constant-forceDevice•Amicrometerheadttedwithaconstant-forcedevice(ratchetorfrictionthimble)isrecommendedformeasurementapplications.•Ifusingamicrometerheadasastop,orwheresavingspaceisapriority,aheadwithoutaratchetisprobablythebestchoice.■SpindleLock•Whenusingamicrometerheadasastopper,problemscausedbylooseningcanbepreventedbyusingamicrometerheadwithaspindleclamp.Thespindleclampalsopreventsthespindlefromchangingpositionwhentheclampisoperated,providingtheuserwithpeaceofmind.■MeasuringRange(Stroke)•Whenchoosingameasuringrangeforamicrometerhead,allowanadequatemargininconsiderationoftheexpectedmeasurementstroke.Sixstrokeranges,5mmto50mm,areavailableforstandardmicrometerheads.•Ifalongstrokerangeofover50mmisrequired,theconcurrentuseofagaugeblockcanextendtheeffectivemeasuringrange.(FigureD)•Inthisguide,therange(orstrokeend)ofthethimbleisindicatedbyadashedline.Considerthethimbleasmovingwithintherangeofthestrokeendstothepositionindicatedbythelinewhendesigningthejig.■Ultra-fineFeedApplications•Dedicatedmicrometerheadsareavailableformanipulatorapplications,etc.,whichrequireultra-nefeedoradjustmentofspindle.■ThimbleDiameter•Thediameterofathimblegreatlyaffectsitsusabilityandthe"fineness"ofpositioning.Asmall-diameterthimbleallowsquickpositioningwhereasalarge-diameterthimbleallowsnepositioningandeasyreadingofthegraduations.Somemodelscombinetheadvantagesofbothfeaturesbymountingacoarse-feedthimble(speeder)onthelarge-diameterthimble.■GraduationStyles•Careisneededwhentakingareadingfromamechanicalmicrometerhead,especiallyiftheuserisunfamiliarwiththemodel.•The"normalgraduation"style,identicaltothatofanoutsidemountedmicrometer,isthestandard.Forthisstylethereadingincreasesasthespindleretractsintothebody.•Onthecontrary,inthe“reversegraduation”stylethereadingincreasesasthespindleadvancesoutofthebody.•The"bidirectionalgraduationstyle"isintendedtofacilitatemeasurementineitherdirection.Thenumbersaredisplayedinblackandredintherespectivedirectionsforeasyreading.•Micrometerheadswithamechanicalorelectronicdigitaldisplay,whichallowdirectreadingofameasurementvalue,arealsoavailable.Thesetypesarefreefrommisreadingerrors.Afurtheradvantageisthattheelectronicdigitaldisplaytypecanenablecomputer-basedstorageandstatisticalprocessingofmeasurementdata.Micrometerheadwithconstant-forcedeviceMicrometerheadwithoutconstant-forcedevice(noratchet)FigureDGaugeblockHead’sstrokeObtainedstroke05504525204505NormalgraduationstyleReversegraduationstyle052520208010900090108020Bidirectionalgraduationstyle3-66
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