ASME B18.2.2-2010 pdf download

ASME B18.2.2-2010 pdf download.Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling Nuts (Inch Series).
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. 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 and Washer-Faced Nuts. The diameter of chamfer circle on double-chamfered nuts and washer-faced nuts shall be within the limits of the maximum width across flats and 95% of the minimum width-across-flats. 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 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 diameter of washer face shall be within the limits of the maximum width across flats and 95% of the minimum width across flats.
3.8.2 SquareNuts. The axis oftapped hole in square 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. 3.10 Threads 3.10.1 Thread Class. Threads shall be Unified Standard, Class 2B, of the series specified in the notes on respective dimensional tables, in accordance with ASME B1.1. Class 3B may be specified by the purchaser if designated at the time of inquiry and order. 3.10.2 Thread Gaging. Unless otherwise specified by the purchaser, gaging for screw thread dimensional acceptability shall be in accordance with Gaging System 21 as specified in ASME B1.3, Screw Thread Gaging Systems for Dimensional Acceptability. 3.11 Material Unless otherwise specified by the purchaser or else- where in this Standard, chemical and mechanical prop- erties of steel nuts shall conform to Grade A of ASTM A 563, Carbon and Alloy Steel Nuts or Grade 2 (square nuts only) of SAE J995. Nuts of other materials such as corrosion resistant(stainless) steel, brass, bronze, and aluminum alloys shall have properties as agreed upon between the manufacturer and purchaser. Refer to ASTM F 594 for information on corrosion resistant alloy steel requirements and ASTM F 467for information on nonferrous materials. 3.12 Finish Unless otherwise specified, nuts shall be supplied with a natural (as-processed) finish, unplated or uncoated. Ifelectroplated finishes are required, reference ASTM F 1941. Other finishes may be specified as indi- cated in the applicable mechanical and performance standards.