AMERICANNATIONALSTANDARDGeneralPurposeMetricTaperedandReducedCrossSectionRetainingRingsTYPE3DM1-HEAVYDUTYEXTERNALRINGSTYPE3EM1-REINFORCED"E"RINGSTYPE3FM1-"C"TYPERINGSANSIB27.8M-1978REAFFIRMED1999FORCURRENTCOMMITTEEPERSONNELPLEASESEEASMEMANUALAS-I1SECRETARIATSOCIETYOFAUTOMOTIVEENGINEERSTHEAMERICANSOCIETYOFMECHANICALENGINEERSPUBLISHEDBYTHEAMERICANSOCIETYOFMECHANICALENGINEERSUnitedEngineeringCenter345East47thStreetNewYork,N.Y.10017CopyrightedmateriallicensedtoStanfordUniversitybyThomsonScientific(www.techstreet.com),downloadedonOct-05-2010byStanfordUniversityUser.Nofurtherreproductionordistributionispermitted.UncontrolledwDateofIssuance:March15,1979Nopartofthisdocumentmaybereproducedinanyform,inanelectronicretrievalsystemorotherwise,withoutthepriorwrittenpermissionofthepublisher.Copyright@1979byTHEAMERICANSOCIETYOFMECHANICALENGINEERSAllRightsReservedPrintedinU.S.A.CopyrightedmateriallicensedtoStanfordUniversitybyThomsonScientific(www.techstreet.com),downloadedonOct-05-2010byStanfordUniversityUser.Nofurtherreproductionordistributionispermitted.UncontrolledwFOREWORDAmericanNationalStandardsCommitteeB27forthestandardizationofplainandlockwasherswasorganizedinMarch1926,asSectionalCommitteeB27undertheaegisoftheAmericanStandardsAssocia-tion(latertheUnitedStatesofAmericaStandardsInstituteand,asofOctober6,1969,theAmericanNationalStandardsInstitute,Inc.),withtheSocietyofAutomotiveEngineersandTheAmericanSocietyofMechanicalEngineersasjointsecretariats.In1950,thisCommitteehadbeendesignatedresponsibilityforstandardizationofwashersandmachinerings.AtameetingofANSIB27StandardsCommitteeheldonFebruary4,1971itwasrecommendedtothesecretariats(ASMEandSAE)thatsubcommittee1,2and4onwashersbemergedintoANSIB18Stan-dardsCommitteeandthatSubcommittee3onretainingringsbecomeaseparateStandardsCommitteeretainingtheB27designation.ThischangewassubsequentlyapprovedbyANSI.FormationofSubcommittee1ontaperedandreducedsectionretainingringswasauthorizedbyStan-dardsCommitteeB27atitsmeetingonOctober15,1974.Atth...
