ASME B18.2.2:2015 pdf free download – Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling Nuts (Inch Series)
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.
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.
3.10.4 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 Acceptability.
3.10.4.1 Thread Gaging of Jam Nuts. Due to the three turn allowance and limited number of threads in jam nuts, NOT GO thread plug gages are not a reliable method for thread acceptance. Unless otherwise speci- fied by the purchaser, jam nut thread acceptablity shall be based on acceptance of the GO thread plug gage and nonacceptance of the NOT GO cylindrical plug gage to inspect minor diameter.
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 A563, Carbon and Alloy Steel Nuts or Grade 2 (square nuts only) of SAE J995. Nuts of other materials suchas corrosionresistant(stainless) steel, brass, bronze, and aluminum alloys shall have properties as agreed upon between the manufacturer and purchaser. Refer to ASTM F594 for information on corrosion resistant alloy steel requirements and ASTM F467 for information on nonferrous materials.