CopyrightedmateriallicensedtoStanfordUniversitybyThomsonScientific(www.techstreet.com),downloadedonOct-05-2010byStanfordUniversityUser.Nofurtherreproductionordistributionispermitted.Uncontrolledwhenprinted.REAFFIRMED2004FORCURRENTCOMMITTEEPERSONNELPLEASEE-MAILCS@asme.orgAMERICANNATIONALSTANDARDPreferredMetricLimitsandFitsANSIB4.2-1978REAFFIRMED1984SECRETARIATTHEAMERICANSOCIETYOFMECHANICALENGINEERSPUBLISHEDBYTHEAMERICANSOCIETYOFMECHANICALENGINEERSUnitedEngineeringCenter345East47thStreetNewYork,N.Y.10017CopyrightedmateriallicensedtoStanfordUniversitybyThomsonScientific(www.techstreet.com),downloadedonOct-05-2010byStanfordUniversityUser.Nofurtherreproductionordistributionispermitted.UncontrolledwNopartofthisdocumentmaybereproducedinanyform,inanelectronicretrievalsystemorotherwise,withoutthepriorwrittenpermissionofthepublisher.Secondprinting-March1979Includescorrectedpagesiii,7,15,43,44,and46.Copyright@1978byTHEAMERICANSOCIETYOFMECHANICALENGINEERSAII'RighnResewedPrintedinU.S.A.CopyrightedmateriallicensedtoStanfordUniversitybyThomsonScientific(www.techstreet.com),downloadedonOct-05-2010byStanfordUniversityUser.Nofurtherreproductionordistributionispermitted.UncontrolledwFOREWORDTheAmericanNationalStandardsCommitteeEMwasorganizedinJune1920,anditdevelopedtheAmericanStandardASAB4a-1925,Tolerances,AllowancesandGagesforMetalFits.AsaresultofcommitteeworkduringWorldWarI1byASAandABC(American,British,Canadian),AmericanStandard,LimitsandFitsforEngineeringandManufacturing(PartI),ASAB4.1-1947,wasproduced.TheprefacetothatdocumentmadesignificantreferencetothecontributionoftheABCmeet-ingsindevelopingagreementonfivebasicprinciples,fourofwhchapplytothepresentstandard.Theserelatedtothedesirabilityofestablishingcommondefinitions,atableofpreferredbasicsizes,asystemofpreferredtolerancesandallowances,andauniformmethodofapplyingtolerances.In1973,theGeneralMotorsCorporationrecognizedaneedforametricstandardsimilartotheIS0R286andpublishedaninterimstandardwhichwaslateradoptedasanANSISpecialMetri...
