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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. 2 REFERENCES Unless otherwise specified, the standards referenced shall be the latest edition at the time of order placement. ASME B1.1, Unified Inch Screw Threads (UN and UNR Thread Form) ASME B1.3, Screw Thread Gaging Systems for Acceptability: Inch and Metric Screw Threads (UN, UNR, UNJ, M, and MJ) 1 ASME B18.12, Glossary of Terms for Mechanical Fasteners ASME B18.18, Quality Assurance for Fasteners ASME B18.24, Part Identifying Number (PIN) Code System for B18 Fastener Products ASME B107 Series, Standards for Hand Tools Publisher: The American Society of Mechanical Engineers (ASME), Two Park Avenue, New York, NY 10016-5990 (www.asme.org) ASTM A563, Standard Specification for Carbon and Alloy Steel Nuts ASTM F467, Standard Specification for Nonferrous Nuts for General Use ASTM F594, Standard Specification for Stainless Steel Nuts ASTM F1941, Specification for Electrodeposited Coatings on Threaded Fasteners [Unified Inch Screw Threads (UN/UNR)] Publisher: American Society for Testing and Materials (ASTM International), 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959 (www.astm.org) SAE J995, Mechanical and Material Requirements for Steel Nuts Publisher: SAE International,400 CommonwealthDrive, Warrendale, PA 15096 (www.sae.org) 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.
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 2 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 indica- tor measurement (FIM) limit indicated in the tables. See Nonmandatory Appendix C for measurement procedure.

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