ASME B18.2.2-2015 pdf free download.Nuts for General Applications: Machine Screw Nuts, 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 dis- tance 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% of the actual nut thickness as measured from the bearing surface shall be less than the minimum width across flats.
NOTE: Nonferrous milled-from-bar hex nuts: The minimum across flats dimensions of nonferrous milled-frombar hex nuts shall not be less than the values tabulated in Tables 1-1 through 13. The maximum across flats size may be greater than the tabu- lated values in Tables 1-1 through 13, but shall not be equal to or greater than the minimum wrench opening shown in Table B-1, Nonmandatory Appendix B.
3.2 Corner Fill A rounding or lack of fill at junction of hex corners with chamfer shall be permissible, provided the width across corners is 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. Unless other- wise specified by the purchaser or in this Standard, nuts in sizes 5 ⁄ 8 in. nominal size and smaller shall be double chamfered. Larger size nuts shall be double-chamfered or have washer-faced bearing surface and chamfered top.
3.3.1 Single-Chamfered Nuts and Washer-Faced Nuts. Diameter of the chamfer circle shall be equal to the maximum width across flats within a tolerance of −15%. The length of chamfer at hex corners shall be from 5% to 15% of the basic thread 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 across flats with a −10% tolerance.
3.4 Countersink Unless otherwise specified in this Standard, tapped holes shall be countersunk on the bearing faces. The maximumcountersinkdiametershall be the thread basic (nominal) majordiameter plus 0.030 in. for 3 ⁄ 8 in. nominal size nuts 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 The nut thickness shall be the overall distance, mea- sured parallel to the axis of nut, from the top of the nut to the bearing surface 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 across flats with a −10% tolerance.
3.7 Slots When specified in the respective dimensional table, slots shall be normal to nut flats. Contour of bottom of slots 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 Hex Nuts. The axis of tapped hole in hex nuts shall be located at true position with respect to the axis of nut body within a tolerance zone having a diameter equivalent to 4% of the maximum width across flats for 1 1 ⁄ 2 in. nominal size nuts 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. The axis oftapped hole insquare nuts shall be located at true position with respect to the axis of nut 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.ASME B18.2.2 pdf download.ASME B18.2.2-2015 pdf free download
