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  • Tops of Nuts. Tops of nuts shall be flat and chamfered, the length of chamfer at hex corners shall be from 5 to 15 percent of the basic thread size. The surface may be slightly convex or rounded.
  • Bearing Surface. Bearing surface shall be at right angle to axis of the threaded hole within a tolerance of 2 degrees; therefore, the maximum total angularity of bearing surface would equal the tangent of specified angle times the diameter of the flange.
  • Concentricity of Tapped Hole. Axis of tapped hole shall be concentric with axis of nut body within a tolerance equal to 3 percent (6 percent FIM) of the maximum width across flats.
  • Countersink. Tapped hole shall be countersunk on the bearing face and may be countersunk on the top. The maximum countersunk 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.
  • Threads. Threads shall be Unified coarse or fine thread series (UNC or UNF series), Class 2B, in accordance with ASME B1.1.
  • Material. Unless otherwise specified, chemical and mechanical properties of steel nuts shall conform with ASTM A563, Grade A, or SAE J995, Grade 2. Nuts of other materials such as corrosion resistant (stainless) steel, brass, bronze and aluminum alloys shall have properties as agreed between the manufacturer and purchaser. The properties for nuts of several grades of corrosion resistant steel alloys are covered in ASTM F594, and of several nonferrous materials in ASTM F467.
  • Nominal Size. Where specifying nominal size in decimals, zeros preceding the decimal and in the fourth decimal place shall be omitted.
Hex & Large Hex Flange Nuts
Unit of Measure
Items Hex & Large Hex Flange Nuts
item-3680
Large Hex Flange Nut, 0.2500" Nominal Dia.
Hex & Large Hex Flange Nuts
item-3681
Large Hex Flange Nut, 0.3125" Nominal Dia.
Hex & Large Hex Flange Nuts
item-3682
Large Hex Flange Nut, 0.3750" Nominal Dia.
Hex & Large Hex Flange Nuts
item-3683
Large Hex Flange Nut, 0.4375" Nominal Dia.
Hex & Large Hex Flange Nuts
item-3684
Large Hex Flange Nut, 0.5000" Nominal Dia.
Manufacturer N/A Industrial Fasteners Institute
Product N/A Hex Flange Nuts
Codes and Standards N/A IFI-145 2002
Unit of Measure N/A English
Nominal Size or Basic Major Dia. of Thread N/A 1/4 in N/A 5/16 in N/A 3/8 in N/A 7/16 in N/A 1/2 in
Nominal Size or Basic Major Dia. of Thread (Decimal) N/A 0.2500 in N/A 0.3125 in N/A 0.3750 in N/A 0.4375 in N/A 0.5000 in
Max. Width Across Flats (F) N/A 0.438 in N/A 0.500 in N/A 0.562 in N/A 0.688 in N/A 0.750 in
Min. Width Across Flats (F) N/A 0.428 in N/A 0.489 in N/A 0.551 in N/A 0.675 in N/A 0.736 in
Max. Width Across Corners (G) N/A 0.505 in N/A 0.577 in N/A 0.650 in N/A 0.794 in N/A 0.866 in
Min. Width Across Corners (G) N/A 0.488 in N/A 0.557 in N/A 0.628 in N/A 0.768 in N/A 0.840 in
Max. Flange Diameter (B) N/A 0.728 in N/A 0.820 in N/A 0.915 in N/A 1.131 in N/A 1.205 in
Min. Flange Diameter (B) N/A 0.700 in N/A 0.790 in N/A 0.885 in N/A 1.100 in N/A 1.175 in
Max. Nut Thickness (H) N/A 0.312 in N/A 0.375 in N/A 0.406 in N/A 0.468 in N/A 0.515 in
Min. Nut Thickness (H) N/A 0.281 in N/A 0.343 in N/A 0.390 in N/A 0.437 in N/A 0.485 in
Min. Wrenching Length (J) N/A 0.15 in N/A 0.20 in N/A 0.240 in N/A 0.26 in N/A 0.29 in
Min. Flange Thickness (K) N/A 0.04 in N/A 0.04 in N/A 0.04 in N/A 0.04 in N/A 0.06 in
Max. Angularity of Bearing Surface N/A 0.024 in N/A 0.028 in N/A 0.031 in N/A 0.038 in N/A 0.041 in