ASME_B18.12-2020.pdf

Glossary of Terms for Mechanical FastenersAN AMERICAN NATIONAL STANDARDASME B18.12-2020(Revision of ASME B18.12-2012)ASME B18.12-2020(Revision of ASME B18.12-2012)Glossary of Termsfor MechanicalFastenersAN AMERICAN NATIONAL STANDARDTwo Park Avenue New York,NY 10016 USAxDate of Issuance:June 30,2020This Standard will be revised when the Society approves the issuance of a new edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of this Standard.Interpretations arepublishedontheCommitteewebpageandunderhttp:/go.asme.org/InterpsDatabase.PeriodicallycertainactionsoftheASMEB18 Committee may be published as Cases.Cases are published on the ASME website under the B18 Committee Page athttp:/go.asme.org/B18committee 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.The B18 Committee Page can be found at http:/go.asme.org/B18committee.There is an option available to automaticallyreceive an e-mail notification when errata are posted to a particular code or standard.This option can be found on theappropriate Committee 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.ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in thisdocument,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.ivCommittee Roster.vCorrespondence With the B18 Committee.vi1Introduction.12Terminology.13Product Families.39Tables2.3.1-1Common Applications of Threaded Fastener Head Styles.133.1.2.1-1Type Designations for Tapping Screws and Metallic Drive Screws.563.1.5-1Screw and Washer Assembly Combinations.68Index.94iiiFOREWORDSectional Committee B18 on Dimensional Standardization of Bolts,Nuts,Rivets,Screws,and Similar Fasteners wasorganized in March 1922 under the procedure of the American Engineering Standards Committee(AESC),with theSociety of Automotive Engineers and The American Society of Mechanical Engineers(ASME)as joint sponsors.Subcommittee10ontheGlossaryofTermsforMechanicalFastenerswasorganizedinFebruary1947.ThepurposeofthesubcommitteewastopromoteandcoordinatethestandardizationoffastenernomenclatureforthoseproductsfallingunderthescopeofthevariousothersubcommitteesoftheB18SectionalCommittee,thedefinitionsthemselvesbeingtheresponsibilityofthecognizantsubcommittee.Itwaslaterdecidedthattermsnotstrictlyintheabovecategorybutcloselyallied should be defined in the Glossary.Duringthedevelopmentperiod,Subcommittee10preparedandstudiedseveraldraftsoftheGlossarybeforeagreeingon a suitable format and content.Tocovercompletelythefield ofmechanical fasteners,ithasbeennecessarytoincludeinthisStandard illustrationsofcertain fastener features and types of fasteners that are of proprietary origin.Because it was impossible to include allvariationsofsuchproprietarydesigns,thisStandardincludesselectedillustrationsthatexemplifythetypeoffastenerorfeature described.This selection was made on an impartial basis.The inclusion of any one proprietary design in thisStandard does not constitute endorsement by the committee or the sponsors,nor is omission of certain styles to beconstrued as rejection of such styles by the committee and sponsors.