ASME B18.2.2:2015 pdf download

ASME B18.2.2:2015 pdf download.Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling Nuts (Inch Series)
1 INTRODUCTION
1.1 Scope 1.1.1 This Standard is intended to cover the com- plete general and dimensional data for the various types of inch series square and hex nuts, including machine screw nuts and coupling nuts, addressed by this Stan- dard. Also included are appendices covering gaging of slots in slotted nuts, wrench openings for nuts, formulas on which dimensional data are based, and measurement of bearing surface runout. It should be understood that where questions arise concerning acceptance ofproduct, the dimensions in the tables shall govern over recalcula- tion by formula. 1.1.2 The inclusion of dimensional data in this Standard is notintended to imply that all ofthe products described herein are stock production sizes. Consumers are requested to consult with manufacturers concerning lists of stock production sizes. 1.2 Comparison to ISO Standards There are no comparable ISO inch fastener standards. 1.3 Dimensions Unless otherwise indicated, units of measurement are expressed in inches. 1.4 Options Where options are allowed, they shall be selected at the manufacturer’s discretion unless otherwise specified by the purchaser. 1.5 Terminology References For definitions ofterminology not specifically defined in this Standard, refer to ASME B18.12.
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-from-bar 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.