ASME B18.2.2-2022 pdf download

ASME B18.2.2-2022 pdf download.Nuts for General Applications: Machine Screw Nuts; and Hex, Square, Hex Flange, and Coupling Nuts (Inch Series).
3 GENERAL DATA 3.1 Width Across Flats The width across flats of nut shall be the overall distance measured, perpendicular to the axis of nut, between two opposite sides of the nut in accordance with the notes on respective dimensional tables. Maximum width across flats shall not be exceeded, except as stated below. No transverse section through the nut between 25% and 75% ofthe actual nutthickness as measured from the bearing surface shall be less than the minimum width across flats. NOTE: Nonferrousmilled-from-barhexnuts: Theminimumacrossflatsdimensionsofnonferrousmilled-from-barhexnutsshallnotbe less than the values tabulated in Tables 1.1.1-1 through 1.1.1-15. The maximum across flats size may be greater than the tabulated values in Tables 1.1.1-1 through 1.1.1-15 but shall not be equal to or greater than the minimum wrench opening shown in Nonmandatory Appendix B, Table B-1. 3.2 Corner Fill Aroundingorlackoffillatjunctionofhexcornerswithchamfershallbepermissible,providedthewidthacrosscorners is within specified limits at and beyond a distance equal to 17.5% ofthe basic thread diameter from the chamfered face. 3.3 Tops of Nuts and Chamfers Topsofnutsshallbeflatandchamfered,exceptcastlenutswherechamferis optional.Unlessotherwisespecifiedbythe purchaserorin this Standard, nuts ofnominal size 5 ∕ 8 in. and smallershall be double-chamfered. Largersize nuts shall be double-chamfered or have washer-faced bearing surface and chamfered top. 3.3.1 Single-Chamfered Nuts and Washer-Faced Nuts. Diameterofthe chamfercircle shall be equal to the maximum width across flats within a tolerance of−15%. The length ofchamfer athex corners shall be from 5% to 15% ofthe basic thread diameter. The surface of the chamfer may be slightly convex or rounded. 3.3.2 Double-Chamfered Nuts. Diameterofthechamfercircle shall be equal to themaximumwidth across flats witha −10% tolerance.
3.4 Countersink Unless otherwise specified in this Standard, tapped holes shall be countersunk on the bearing faces. The maximum countersink diameter shall be the thread basic (nominal) major diameter plus 0.030 in. for nuts of nominal size 3 ∕ 8 in. and smaller, and 1.08 times the basic major diameter for nuts larger than 3 ∕ 8 in. No part of the threaded portion shall project beyond the bearing surface. 3.5 Nut Thickness Thenutthicknessshallbetheoveralldistance,measuredparalleltotheaxisofnut,fromthetop ofthenuttothebearing surface and shall include the thickness of the washer face where provided. 3.6 Washer Face Diameter Unlessotherwisespecified,theoutsidediameterofwasherfaceshallbeequalto the maximumwidthacross flats witha −10% tolerance. 3.7 Slots Whenspecified in the respective dimensional table, slots shall be normal to nutflats. The contourofthe bottom ofslots shall be at manufacturer’s option. Requirements for gaging slots are specified in Mandatory Appendix I.
3.8 True Position of Tapped Hole 3.8.1 HexNuts. The axis oftapped hole in hexnuts shall be located attrue position with respectto the axis ofnutbody within a tolerance zone having a diameter equivalent to 4% ofthe maximum width across flats for nuts ofnominal size 1 1 ∕ 2 in. or smaller and 6% of the maximum width across flats for nuts larger than 1 1 ∕ 2 in., regardless of feature size. 3.8.2 SquareNuts. Theaxis oftappedholeinsquarenuts shallbelocatedattruepositionwithrespecttotheaxis ofnut body within a tolerance zone having a diameter equivalent to 10% of the maximum width across flats, regardless of feature size. 3.9 Bearing Surface Perpendicularity Bearing surface shall be flat and perpendicular to the axis of the threaded hole within the specified full indicator measurement (FIM) limit indicated in the tables. See Nonmandatory Appendix C for measurement procedure. 3.10 Threads 3.10.1 Thread Standard. Threads shall meet the requirements of ASME B1.1. 3.10.2 Thread Class. Unless otherwise specified, threads shall be Unified Standard, Class 2B. 3.10.3 Thread Series. Thread series on nuts may be coarse (UNC), fine (UNF), or 8 thread series (8UN). 3.10.4 Thread Gaging.Unlessotherwisespecifiedbythepurchaser,gagingforscrewthreaddimensionalacceptability shall be in accordance with Gaging System 21 as specified in ASME B1.3. 3.10.4.1 Thread Gaging ofJamNuts. Duetothethreeturnallowanceandlimitednumberofthreadsinjamnuts,NOT GO thread plug gages are not a reliable method for thread acceptance. Unless otherwise specified by the purchaser, jam nut thread acceptability shall be based on acceptance of the GO thread plug gage and nonacceptance of the NOT GO cylindrical plug gage to inspect minor diameter.