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)
Publisher:American Society for Testing and Materials (ASTM International),100 BarrHarbor Drive,P.O.Box C700,WestConshohocken.PA 19428-2959 (www.astm.orgJ
SAE J995, Mechanical and Material Requirements for Steel Nuts
Publisher: SAE International, 400 Commonwealth Drive, Warrendale, PA 15096(www.sae.org)
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 twoopposite 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 nutbetween 25% and 75% of the actual nut thickness as measured from the bearing surface shall be less than the minimumwidth across flats.
NOTE;Nonferrous milled-from-bar hexnutst:The minimum acrossflats dimensions ofnonferrous milled-from-bar hex nuts shallnot beless 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 tabulatedvalues 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 inNonmandatory Appendix B,Table B-1.
3.2 Corner Fill
Arounding or lack offill at junction of hexcorners with chamfer shall be permissible,provided the width across cornersis within specified limits at and beyond a distance equal to 17.5% of the basic thread diameter from the chamfered face.3.3 Tops of Nuts and Chamfers
Tops of nuts shall be flat and chamfered, exceptcastle nuts where chamfer is optional.Unless otherwise specified by thepurchaser or in this Standard, nuts of nominal size %/g in.and smaller shall be double-chamfered.Larger size nuts shall bedouble-chamfered or have washer-faced bearing surface and chamfered top.
3.3.1 Single-Chamfered Nuts and Washer-Faced Nuts. Diameter ofthe chamfer circle shall be equal to the maximumwidth across flats within a tolerance of-15%.The length of chamfer at hex corners shall be from 5% to 15% of the basicthread diameter. The surface of the chamfer may be slightly convex or rounded.
3.3.2 Double-Chamfered Nuts. Diameter of the chamfer circle shall be equal to the maximum width acrossflats with a-10% tolerance.
3.4 Countersink
Unless otherwise specified in this Standard, tapped holes shall be countersunk on the bearing faces.The maximumcountersink diameter shall be the thread basic (nominal) major diameter plus 0.030 in.for nuts of nominal sizein. and smaller, and 1.08 times the basic major diameter for nuts larger than % in. No part of the threadedportion shall project beyond the bearing surface.
3.5 Nut Thickness
The nut thickness shall be the overalldistance,measured parallelto the axis of nut,from the top of the nut to the bearingsurface and shall include the thickness of the washer face where provided.
3.6 Washer Face Diameter
Unless otherwise specified, the outside diameter of washer face shall be equal to the maximum width acrossflats with a-10% tolerance.
3.7 Slots
When specified in the respective dimensional table, slots shall be normal to nut flats.The contour of the bottom of slotsshall be at manufacturer’s option. Requirements for gaging slots are specified in Mandatory Appendix 1.
3.8 True Position of Tapped Hole
3.8.1 HexNuts.The axis of tapped hole in hex nuts shall be located at true position with respect to the axis of nut bodywithin a tolerance zone having a diameter equivalent to 4% of the maximum width across flats for nuts of nominal size11/ in. or smaller and 6% of the maximum width across flats for nuts larger than 11/z in., regardless of feature size.3.8.2 Square Nuts.The axis of tapped hole in square nutsshall be located at true position with respect to the axis of nutbody within a tolerance zone having a diameter equivalent to 10% of the maximum width across flats, regardless offeature size.
3.9 Bearing Surface Perpendicularity
Bearing surface shall be flat and perpendicular to the axis of the threaded hole within the specified full indicatormeasurement (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.Unless otherwise specified by the purchaser,gagingfor screwthreaddimensional acceptabilityshall be in accordance with Gaging System 21 as specified in ASME B1.3.
3.10.4.1 Thread Gaging of Jam Nuts.Due to the three turn allowance and limited number of threads injam nuts,NOTGO thread plug gages are not a reliable method for thread acceptance.Unless otherwise specified by the purchaser, jamnut thread acceptability shall be based on acceptance of the G0 thread plug gage and nonacceptance of the NOT GOcylindrical plug gage to inspect minor diameter.
3.11 Material
Unless otherwisespecified by the purchaser or elsewhere in this Standard, chemicaland mechanical properties of steelnuts shall conform to Grade A of ASTM A563 or Grade 2 (square nuts only) of SAE J995.Nuts of other materials such ascorrosion resistant (stainless)steel, brass, bronze, and aluminum alloys shall have properties as agreed upon between themanufacturer and purchaser. Refer to ASTM F594 for information on corrosion resistant alloy steel requirements andASTM F467 for information on nonferrous materials.
3.12 Finish
Unless otherwise specified, nuts shall be supplied with a natural (as-processed) finish, unplated or uncoated.Ilf elec-troplated finishes are required, reference ASTM F1941.Other finishes may be specified as indicated in the applicablemechanical and performance standards.
3.13 Designation
3.13.1 Nuts shall be designated by the following data in the sequence shown: product name; dimensional standard,nominal size (fraction or decimal); threads per inch; basic width across flats (when applicable); mechanical and perfor-mance standard; and grade protective finish (including specification and thickness), if required.
EXAMPLES:
(1) Square Nut, ASME B18.2.2，1-13,ASTM A563 Grade A,Zinc Plated per ASTM F1941 Fe/Zn 3A(2j Hex Nut,ASME B18.2.2,/4-16,SAE J995 Grade 5,Steel
(3) Hex Thick Slotted Nut, ASME B18.2.2,1.000-8,ASTM F594 (Alloy Group 1) Corrosion Resistant Steel(4)Small Pattern Hex Machine Screw Nut,ASME B18.2.2,#10-32,5i16 Across Flats, Steel, Plain
3.13.2 For part identification numbers (PIN), refer to ASME B18.24.
3.14 Grade and Manufacturer’s ldentification Marking
Grade and manufacturer’s markings shall be applied as required by the applicable mechanical and performance stan-dard except that markings are not required for the machine screw nuts per Tables 1.1.1-1 and 1.1.1-2.