ASME_B1.1-2019.pdf

Unified Inch Screw Threads(UN,UNR,and UNJ Thread Forms)AN AM E R IC AN NAT IO NAL STANDARDASME B1.1-2019Revision of ASME B1.1-2003(R2018)ASME B1.1-2019Revision of ASME B1.1-2003(R2018)Unified Inch ScrewThreads(UN,UNR,andUNJ Thread Forms)AN AMERICAN NATIONAL STANDARDTwo Park Avenue New York,NY 10016 USAxDate of Issuance:June 30,2020ThenexteditionofthisStandardisscheduledforpublicationin2024.ThisStandardwillbecomeeffective1yearaftertheDateofIssuance.Periodically certain actions of the ASME B1 Committee may be published as Cases.Cases are published on the ASME websiteunder the B1 Committee Page at http:/go.asme.org/B1committee as they are issued.Errata to codes and standards may be posted on the ASME website under the Committee Pages to provide corrections toincorrectlypublisheditems,ortocorrecttypographicalorgrammaticalerrorsincodesandstandards.Sucherratashallbeusedon the date posted.TheB1CommitteePagecanbefoundathttp:/go.asme.org/B1committee.Thereisanoptionavailabletoautomaticallyreceivean e-mail notification when errata are posted to a particular code or standard.This option can be found on the appropriateCommittee Page after selecting“Errata”in the“Publication Information”section.ASME is the registered trademark of The American Society of Mechanical Engineers.ThiscodeorstandardwasdevelopedunderproceduresaccreditedasmeetingthecriteriaforAmericanNationalStandards.TheStandardsCommitteethatapprovedthecodeorstandardwasbalancedtoassurethatindividualsfromcompetentandconcernedinterestshavehadanopportunityto participate.The proposed codeorstandardwasmadeavailable forpublic reviewandcommentthatprovidesanopportunityfor additional public input from industry,academia,regulatory agencies,and the public-at-large.ASME does not“approve,”“rate,”or endorse any item,construction,proprietary device,or activity.ASMEdoes nottake anyposition with respectto thevalidity ofany patientrights assertedin connection with anyitemsmentioned inthisdocument,anddoesnotundertaketoinsureanyoneutilizingastandardagainstliabilityforinfringementofanyapplicableletterspatent,norassumeanysuchliability.Usersofacodeorstandardareexpresslyadvisedthatdeterminationofthevalidityofanysuchpatentrights,andtherisk of infringement of such rights,is entirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted as government or industryendorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the established ASME proceduresand policies,which precludes the issuance of interpretations by individuals.No part of 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 EngineersTwo Park Avenue,New York,NY 10016-5990Copyright 2020 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll Rights ReservedPrinted in U.S.A.CONTENTSForeword.vCommittee Roster.viiCorrespondence With the B1 Committee.viii1General.12Screw Thread Profile.33Screw Thread Series.54Screw Thread Classes.775Screw Thread Allowance and Tolerance.776Screw Thread Designation.1067Dimensional Accommodation of Coating or Plating for 60-Deg Threads.1108Limits of Size for Standard(UN,UNR,and UNJ)and Special(UNS,UNRS,and UNJS)Series ofThreads.1159Thread Form Tolerances.11710Formulas and Nomenclature for Thread Form.14211Tables of Basic Dimensions.142Nonmandatory AppendicesATerminology and Identification of Unified Inch Screw Threads.148BThread Strength Design Formulas.150CUnified Inch Screw Threads Metric Translation.151DSpecial Threads.152EChanges to ASME B1.1-1989,Tables 3A and 3B.161FSpecial Lengths of Engagement Specifications and Designations.180Figures1Illustration of Assembly Interference of UNJ-3A Thread and UN-3B Thread in the MaximumMaterial Condition.22Basic Profile for UN and UNR Screw Threads.33Basic Profile for UNJ Screw Threads.44Root Radius of UNJ External Thread.45DispositionofDiametralTolerances,Allowance,andCrestClearanceforUnifiedInchScrewThreadSeries UN,Classes 1A,2A,1B,and 2B.66DispositionofDiametralTolerancesandCrestClearanceforUnifiedInchScrewThreadSeriesUN,Classes 3A and 3B.77DispositionofDiametralTolerances,Allowance,andCrestClearanceforUnifiedInchScrewThreadSeries UNR,Classes 1A and 2A,and Series UN,Classes 1B and 2B.88DispositionofDiametralTolerancesandCrestClearanceforUnifiedInchScrewThreadSeriesUNR,Class 3A and Series UN,Class 3B.99External UNJ Thread Design Profile and Tolerances.10iii10DispositionofDiametralTolerances,Allowance,andCrestClearanceforUnifiedInchScrewThreadSeries UNJ,Classes 2A and 2B.1111DispositionofDiametralTolerancesandCrestClearanceforUnifiedInchScrewThreadSeriesUNJ,Classes 3A and 3B.1212Internal UNJ Thread Design Profile and Tolerances.7813Basic Method of Designating Screw Threads.10714Ratio of Pitch Diameter Change to Thickness of Coating on 60-deg Threads.11215Effect of Electrodeposited