>> P.13-15
45051DI.0005mm4545051DIV0005mm45OutersleeveThimbleRatchetEffectofMisalignmentonAccuracy(InsideMicrometer)Fig.1XFig.2ℓLℓXL100545Thimble(2)(1)35406789OutersleeveTakingReadingsGraduation0.005mm(1)Outersleevereading:(2)Thimblereading:Holtestreading:350.015mmmm35.015mmInsideMeasuringInstrumentsNomenclature(Holtest)ContactpointConeSpindle△ℓ:Errorinmeasurement△ℓ:L-ℓℓ:InsidediametertobemeasuredL:LengthmeasuredwithaxialoffsetXX:Offsetinaxialdirection△ℓ:Errorinmeasurement△ℓ:L-ℓℓ:InsidediametertobemeasuredL:LengthmeasuredwithaxialoffsetXX:Offsetinaxialdirection=√ℓ2+X2-ℓ=√ℓ2-X2-ℓIftheInsideMicrometerismisalignedintheaxialorradialdirectionbyanoffsetdistanceXwhenameasurementistaken,asinFig.1and2,thenthatmeasurementwillbeinerrorasshowninthegraphbelow(constructedfromtheformulagivenabove).Theerrorispositiveforaxialmisalignmentandnegativeforradialmisalignment.ℓ=200mmℓ=500mmℓ=1000mm0.100.090.080.070.060.050.040.030.020.01misalignment)(mm)andnegativeforradial,Error(positiveforaxial,12789103456Misalignment(offset)ofoneendofmicrometer(mm)ChangesinMeasuredValuesatDifferentMeasuringPointsWhenHoltestisused,themeasuredvaluediffersbetweenmeasurementacrosstheanvilandthemeasurementonlyatthetipoftheanvilduetotheproductmechanism.Adjustthestartpointunderthesameconditionbeforemeasurement.Whenyouusethetipoftheanvilformeasurement,adjustthestartpointforusingthetipoftheanvil.WorkpieceAdjustmentofstartpointMeasurementErrorDuetoInsideMicrometerTemperatureChangeTemperaturechangescausemeasuringtoolstoproduceerrorsinmeasurement.inWhenmakingthehand,itisnecessarytopreventexpansionofthemicrometerduetobodytemperaturebyholdingthethermallyinsulatingplatewithgloves,etc.ameasurementbyholdinginsidemicrometerdirectlyanInsideMeasuringInstruments13-15
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