• Tops of Nuts. Tops of nuts shall be flat and chamfered or washer crowned. Diameter of the chamfer circle shall be equal to the maximum width across flats within a tolerance of minus 15 percent. The surface of chamfer may be slightly convex or rounded.
  • Width Across Flats. Maximum width across flats shall not be exceeded. No transverse section through the nut between 25 and 75 percent of the actual nut thickness as measured from the bearing surface shall be less than the minimum width across flats.
  • Bearing Surface. Bearing surface shall be perpendicular to the axis of the threaded hole within a tolerance of 3 deg for 1 in. nominal size nuts and smaller, and 2 deg for nuts larger than 1 in.
  • True Position of Tapped Hole. The axis of tapped hole shall be located at true position with respect to the axis of nut body within a tolerance zone having a diameter equivalent to 10 percent of the maximum width across flats, regardless of feature size.
  • Threads. Threads shall be Unified coarse thread series (UNC series), Class 2B, in accordance with ASME B1.1.
  • Material. Unless otherwise specified, chemical and mechanical properties of steel nuts shall conform with Grade A of ASTM A563. 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. 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.
Unit of Measure

Manufacturer

Manufacturer

N/A Industrial Fasteners Institute

Specifications

Product

N/A Nuts

Unit of Measure

N/A English

Nominal Size or Basic Major Dia. of Thread

N/A 1-1/2 in

Nominal Size or Basic Major Dia. of Thread (Decimal)

N/A 1.5000 in

Basic Width Across Flats (F)

N/A 2-3/8 in

Max. Width Across Flats (F)

N/A 2.375 in

Min. Width Across Flats (F)

N/A 2.300 in

Max. Width Across Corners (G)

N/A 3.359 in

Min. Width Across Corners (G)

N/A 3.128 in

Basic Thickness (H)

N/A 1-1/2 in

Max. Thickness (H)

N/A 1.536 in

Min. Thickness (H)

N/A 1.433 in

Codes and Standards

Codes and Standards

N/A ASME/ANSI B18.2.2 1987 (R 1999)
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