1、ASME B1.30-2002(Revision of ASME B1.30M-1992)SCREW THREADS:STANDARD PRACTICEFOR CALCULATINGAND ROUNDINGDIMENSIONSAN AMERICAN NATIONAL STANDARDIntentionally left blank AN AMERICAN NATIONAL STANDARDSCREW THREADS:STANDARD PRACTICEFOR CALCULATINGAND ROUNDINGDIMENSIONSASME B1.30-2002Revision of ASME B1.3
2、0M-1992Date of Issuance: April 25, 2003This Standard will be revised when the Society approves the issuance of a new edition. There willbe no addenda or written interpretations of the requirements of this Standard issued to this edition.ASME is the registered trademark of The American Society of Mec
3、hanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity t
4、o participate. The proposed code or standard was madeavailableforpublicreviewandcommentthatprovidesanopportunityforadditionalpublicinputfromindustry,academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or acti
5、vity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with anyitems mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent, nor assume any such
6、 liability. Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights, and the risk of infringement of such rights, isentirely their own responsibility.Participation by federal agency representative(s) or person(s) affiliated with industry is not t
7、o be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of
8、this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2003 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll righ
9、ts reservedPrinted in U.S.A.CONTENTSForeword ivCommitteeRoster v1 General . 12 Rounding of Decimal Values 13 Calculations From Formulas 24 Thread Form Constants . 2Tables1 NumberofDecimalPlacesUsedinCalculations 22 ExampleofExternalInchScrewThreads,12-28UNEF-2A. 43 ExampleofInternalInchScrewThreads,
10、12-28UNEF-2B 74 ExampleofExternalInchScrewThreads,1964-36UNS-2A. 95 ExampleofInternalInchScrewThreads,1964-36UNS-2B 126 ExampleofExternalMetricScrewThreads,M12H115471.75-4g6g . 147 ExampleofInternalMetricScrewThreads,M12H115471.75-6H 168 ExampleofExternalMetricScrewThreads,M13H115470.9-4g6g 189 Exam
11、pleofInternalMetricScrewThreads,M13H115470.9-6H. 2010 ThreadFormData. 22Nonmandatory AppendixA ThreadCharacteristicsGovernedbythisStandard 23iiiFOREWORDTheAmericanNationalStandardsCommitteeB1forstandardizationofscrewthreadswasorganizedin1920assectionalCommitteeB1underthesponsorshipoftheAmericanEngin
12、eeringStandardsCommittee(latertheAmericanStandardsAssociation,thentheUnitedStatesofAmericaStandardsInstituteandasofOctober6,1969,theAmericanNationalStandardsInstitute,Inc.),withtheSocietyofAutomotiveEngineersandTheAmericanSocietyofMechanicalEngineersas joint sponsors. As a result, a great deal of ef
13、fort was expended through the years towarddevelopmentofseveralscrewthreadstandards.Recognizingtheneedtostandardizethemethodofroundingdecimalvaluesinthecalculationofscrewthreaddimemsions,theASMEStandardsCommitteeB1chargedSubcommittee30withtheresponsibilityforproducingsuchastandard.ThisStandarddesigna
14、tedASMEB1.30wasdevelopedonlytoserveasthebasisforroundingofdecimalvaluesassociatedwiththecomputationofscrewthreaddimensions.The examples and formulas depicted within this Standard are for reference only and arepresentedonlytoclarifytheroundingproceduresdescribed.Whencalculatingthedifferentthreadchara
15、cteristicsforaparticularthreadform,refertotheappropriateASMEB1standardfortheformulasandmethodologyofcalculationforthatthread.ThisStandardwasoriginallyapprovedasanAmericanNationalStandardonJune29,1992.Thisissueupdatesthe1992issueandincludes:(a) theadditionofanotetopara.1.2fortheclarificationoftheuseo
16、fthisStandardformetricapplications;(b) theadditionofanexceptioninpara.3.1.3tothenumberofdecimalplacesfortheallowance2AwhenusedinintermediatecalculationsasTd2;(c) theadditionofthemaximumexternalUNminordiameter,maximumandminimuminternalpitchdiametersandtheminimuminternalmajordiametertotheexampleinpara
17、.3.2.1;(d) removal of Appendix A containing various common values for 60 deg thread elements.This was done because the values are either listed or can be calculated by formulas in otherexistingB1standards;(e) theadditionofanexampleforastandardmetricsizethatislistedinASMEB1.13MandISO261;(f) theadditi
18、onofanexampleforaspecialinchsizeshowinghowtoroundnumberswithaninfinitenumberofdigitsafterthedecimalpoint;(g) added a new Appendix A with a table listing the number of decimal places for each ofthethreadcharacteristicsusedintheexamplesinB1.30.SuggestionsforimprovementofthisStandardwillbewelcome.Theys
19、houldbesenttoSecretary,ASMEB1StandardsCommittee,ThreeParkAvenue,NewYork,NY10016-5990U.S.A.ThisrevisionwasapprovedasanAmericanNationalStandardonJuly12,2002.ivASME STANDARDS COMMITTEE B1Standardization and Unification of Screw Threads(The following is the roster of the Committee at the time of approva
20、l of this Standard.)OFFICERSA. L. Barrows, ChairD. S. George, Vice ChairJ. R. Bird, SecretaryCOMMITTEE PERSONNELG. L. Allen, The L. S. Starrett Co.A. L. Barrows, Kennametal-IPGM. H. Bernier, Standard Nut and BoltJ. R. Bird, The American Society of Mechanical EngineersF. G. Calderone, Quality Systems
21、 ImplementersJ. Davis, U.S. Nuclear Regulatory CommissionL. N. Dixon, Jr., General ElectricR. Dodge, Pennoyer-Dodge Co.G. A. Flannery, Mercury Gage Co.D. Skierski, Alternate, Mercury Gage Co.H. N. Frost, Defense Supply Center PhiladelphiaD. S. George, Ford Motor Co.J. R. Gervasi, Kerr Lakeside Inc.J
22、. Greenslade, Greenslade EXAMPLE:1.01235 1.01241.0123500 1.01241.012345 1.012351.01234500 1.01235(b) ifthe5nextbeyondthefigureinthelastplacetoberetainedarefollowedbyanyfiguresotherthanzero,ASME B1.30-2002 SCREW THREADS: STANDARD PRACTICE FORCALCULATING AND ROUNDING DIMENSIONSTable 1Number of Decimal
23、 Places Used in CalculationsUnits Pitch Constants Intermediate FinalInch 8 8 6 4 (except as outlined in para. 3.1.3)Metric as designated 7 5 3thefigureinthelastplaceretainedshouldbeincreasedby1.EXAMPLE:1.0123501 1.01241.0123599 1.01241.01234501 1.012351.01234599 1.012352.1.4 Thefinalroundedvalueisob
24、tainedfromthemost precise value available and not from a series ofsuccessiverounding.Forexample,0.5499shouldberoundedto0.550,0.55and0.5(not0.6),sincethemostprecisevalueavailableislessthan0.55.Similarly,0.5501shouldberoundedas0.550,0.55and0.6,sincethemostprecisevalueavailableismorethan0.55.Inthecaseo
25、f0.5500roundingshouldbe0.550,0.55and0.6,sincethemostprecisevalueavailableis0.5500.3 CALCULATIONS FROM FORMULAS3.1 General Rules3.1.1 Valuesforpitchandconstantsderivedfromafunction of pitch are used out to eight decimal placesforinchseries.Theeightplacevaluesareobtainedbyroundingtheirtruncatedtenplac
26、evalues.Sevendecimalplacevaluesformetricseriesconstantsarederivedbyroundingtheirtruncatednineplacevalues.Seepara.4forthreadformconstants.Valuesusedinintermediatecalculationsareroundedtotwoplacesbeyondthenum-ber of decimal places retained for the final value, seeTable1.EXAMPLE:np28threadsperinchPp1/n
27、Pp1/28Pp0.0357142857Pp0.035714293.1.2 Roundingtothefinalvalueisthelaststepinacalculation.3.1.3 Forinchscrewthreaddimensions,fourdecimalplacesarerequiredforthefinalvaluesofpitchdiameter,majordiameter,andminordiameterwiththeexceptionofClass1Band2Binternalthreadminordiametersforthreadsizes0.138andlarge
28、r,seebelow.Thefinalvaluesfortheallowancesandtolerancesappliedtothreadele-ments are expressed to four decimal places except for2externalthreadpitchdiametertolerance,Td2,whichisexpressedtosixdecimalplaces.(a) MinorDiameterExceptionsforInternalThreads:(1) MinimumMinorDiameter.Allclassesarecalcu-latedan
29、dthenroundedofftothenearest0.001in.andexpressedinthreedecimalplacesforsizes0.138in.andlarger.ForClass3B,azeroisaddedtoyieldfourdecimalplaces.(2) MaximumMinorDiameter.Allclassesarecalcu-latedbeforerounding,thenroundedforClasses1Band2Btothenearest0.001in.forsizes0.138in.andlarger.Class3Bvaluesareround
30、edtofourdecimalplaces.3.1.4 Metricscrewthreadsaredimensionedinmilli-meters.Thefinalvaluesofpitchdiameter,majordiame-ter,minordiameter,allowanceandthreadelementtolerancesareexpressedtothreedecimalplaces.3.1.5 Values containing multiple trailing zeros outto the required number of decimal places can be
31、expressedbydisplayingonlytwoofthembeyondthelastsignificantdigit.EXAMPLE: 20 threads per inch has a pitch equal to 0.05000000andcanbeexpressedas0.0500.3.2 ExamplesTheformulasintheexamplesforinchscrewthreadsinTables2,3,4and5arebasedonthoselistedinASMEB1.1, Unified Inch Screw Threads. Tables 2 and 3 ar
32、ebasedonasizethatwhenconvertedfromafractiontoa decimal will result in a number that has only fourdecimalplaces.Tables4and5arebasedonasizethatwhen converted will result in a number with infinitenumbersofdigitsafterthedecimalpoint.TheformulasintheexamplesformetricscrewthreadsinTables6,7,8and9arebasedo
33、nthoselistedinASMEB1.13M,MetricScrewThreads.Tables6and7showtheuseofthetabulatedvaluesforallowancesandtolerances(inaccordancewithISO965-1)forthecalculationofsizelimitsforstandarddiameter/pitchcombinationslistedinbothISO261andASMEB1.13M.Theconstantvaluesdifferfromthoseusedforinchscrewthreads,inaccor-d
34、ancewiththepolicyofroundingofthisStandard,becausemetriclimitsofsizeareexpressedtoonlythreedecimalplacesratherthanfour.4 THREAD FORM CONSTANTSForthreadformdatatables,seeTable10.Thenumberof decimal places and the manner in which they areSCREW THREADS: STANDARD PRACTICE FOR ASME B1.30-2002CALCULATING A
35、ND ROUNDING DIMENSIONSlistedshouldbeconsistent.Threadformconstantsprintedinolderthreadstandardsarebasedonafunctionofthreadheight(H)orpitch(P).Theequivalentofthecorresponding function is also listed. There are someconstantsthatwouldrequirethesevaluesto8or7deci-malplacesbeforetheywouldroundtoequivalen
36、tval-ues.Forstandardizationthetabulatedlistingofthread3valuesbasedonafunctionofpitchhasbeenestablished,withthreadheightusedasareferenceonly.Allthreadcalculations are to be performed using a function ofpitch (P), rounded to 8 decimal places for inch seriesand as designated for metric series, not a fu
37、nction ofthreadheight(H).Threadheightistobeusedforrefer-enceonly.ASME B1.30-2002 SCREW THREADS: STANDARD PRACTICE FORCALCULATING AND ROUNDING DIMENSIONSTable2ExampleofExternalInchScrewThreads,12-28UNEF-2AThreadSizep12-28or0.5000-28UNEF-2ACharacteristicDescriptionExampleofSizeCalculationAdditionalInf
38、ormation(1)Maximumexternalmajordiameter(dmax.)dmax.pdbsces.pBasicmajordiameter(dbsc)allowance(es)dbscp0.5000Thisisthefinalvalueofthebasicmajordiameterwhichisroundedtofourdecimalplaces.esp0.300(Td2forclass2A)FortheClass2Apitchdiametertolerance,seeTable2(4).esp0.300(0.003668)Thesixdecimalplacevaluefor
39、Class2Apitchdiametertolerance(Td2)isusedinthiscalculation.esp0.001100Thisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofes.esp0.0011.dmax.p0.50000.0011.dmax.p0.4989.(2)Minimumexternalmajordiameter(dmin.)dmin.pdmax.Td.pMaximumexternalmajordiameter(dmax.)majordiametertolerance(Td)Tdp0.0603H2
40、0906P2.Tdp0.0603H20906(0.03571429)2Allthreadcalculationsaretobeperformedusing(P)roundedto8decimalplaces.Tdp0.0603H209060.001276).Tdp0.060(0.108463).Tdp0.006508ThisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofTd.Tdp0.0065.dmin.p0.49890.0065.dmin.p0.4924.4SCREW THREADS: STANDARD PRACTICE F
41、OR ASME B1.30-2002CALCULATING AND ROUNDING DIMENSIONSTable2ExampleofExternalInchScrewThreads,12-28UNEF-2A(Contd)ThreadSizep12-28or0.5000-28UNEF-2ACharacteristicDescriptionExampleofSizeCalculationAdditionalInformation(3)Maximumexternalpitchdiameter(d2max.)d2max.pdmax.2has.pMaximumexternalmajordiamete
42、r(dmax.)twicethe2hasp0.64951905P.externalthreadaddendum(2has)2hasp0.64951905(0.03571429)Allthreadcalculationsaretobeperformedusing(P)roundedto8decimalplaces.2hasp0.023197.d2max.p0.49890.023197.d2max.p0.475703Thisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofd2max.d2max.p0.4757.(4)Minimume
43、xternalpitchdiameter(d2min.)d2min.pd2max.Td2.pMaximumexternalpitchdiameter(d2max.)externalpitchdiametertolerance(Td2)Td2p0.00153H20906dbsc+0.0015H20906LE+0.0153H20906P2LE(lengthofengagement)requiredinthisexample,isequalto9P.SeeASMEB1.1forLEapplicationsforotherthreadseries.Td2p0.00153H209060.5000+0.0
44、015H209069(0.03571429)+0.0153H20906(0.03571429)2.Td2p0.00153H209060.5000+0.0015H209060.321429+0.0153H209060.001276.Td2p(0.0015)(0.793701)+(0.0015)(0.566947)+(0.015)(0.108463).Td2p0.001191+0.000850+0.001627.Td2p0.003668Thisfigureisroundedtosixdecimalplacestoobtainthefinalvalueoftheexternalpitchdiamet
45、ertoleranceTd2.d2min.p0.47570.003668.d2min.p0.472032Thisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofd2min.d2min.p0.4720.5ASME B1.30-2002 SCREW THREADS: STANDARD PRACTICE FORCALCULATING AND ROUNDING DIMENSIONSTable2ExampleofExternalInchScrewThreads,12-28UNEF-2A(Contd)ThreadSizep12-28or0.
46、5000-28UNEF-2ACharacteristicDescriptionExampleofSizeCalculationAdditionalInformation(5)MaximumexternalUNRminordiameter(d3max.)d3max.pdmax.2hs.pMaximumexternalmajordiameter(dmax.)doubleheight2hsp1.19078493P.ofexternalUNRthread(2hs)2hsp1.19078493(0.03571429)Allthreadcalculationsaretobeperformedusing(P
47、)roundedto8decimalplaces.2hsp0.042528.d3max.p0.49890.042528.d3max.p0.456372Thisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofd3max.d3max.p0.4564.(6)MaximumexternalUNminordiameter(d1max.)d1max.pdmax.2hs.pMaximumexternalmajordiameter(dmax.)doubleheight2hsp1.08253175PForUNthreads,2hsp2hnofex
48、ternalUNthread(2hs)2hsp1.08253175(0.03571429)Allthreadcalculationsaretobeperformedusing(P)roundedto8decimalplaces.2hsp0.038662.d1max.p0.49890.038662.d1max.p0.460238Thisfigureisroundedtofourdecimalplacestoobtainthefinalvalueofd1max.d1max.p0.4602.GENERALNOTES:(a)Alldimensionsexpressedininchesforcalcul
49、ationsinthistable.(b)Pp1/np1/28p0.03571429.6SCREW THREADS: STANDARD PRACTICE FOR ASME B1.30-2002CALCULATING AND ROUNDING DIMENSIONSTable3ExampleofInternalInchScrewThreads,12-28UNEF-2BThreadSizep12-28or0.5000-28UNEF-2BCharacteristicDescriptionExampleofSizeCalculationAdditionalInformation(1)Minimuminternalminordiameter(D1min.)D1min.pDbsc2hn.pBasicmajordiameter(Dbsc)doubleheightofinternal2hnp1.08253175P.thread(2hn)2hnp1.08253175(0.03571429)Allthreadcalculationsaretobeperformedusing(P)roundedto8decimalplaces.2hnp0.0386
