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Grade A Heavy Hex Nut

Selected A563 Grade A Heavy Hex Nut BlackGrade A Heavy Hex Nut, Galvanized
A563 Grade A Heavy Hex Nut BlackGrade A Heavy Hex Nut, Galvanized

ASTM A563 Grade A heavy hex nuts are made from carbon steel. Dimensional specifications are governed by ASME B18.2.2. Grade markings are not required for A563 Grade A heavy hex nuts, though in some cases Grade A nuts may be marked with the letter A. ASTM A563 covers standard specifications for carbon and alloy steel nuts. Heavy hex nuts provide increased bearing surface area over finished nuts.

Products

Mechanical Properties

Carbon & Alloy Steel Per ASTM A563-2015
Diameter Proof Load Stress (1) Core Hardness
ksi Rockwell
Non-Zinc-Coated   (2) Zinc-Coated (2) Min Max
1/4" thru 4" 100 75 B68 C32
  1. 1. To determine nut proof load in pounds, multiply the appropriate nut proof load stress by the tensile stress area of the thread.
  2. 2. Non-zinc-coated nuts are nuts intended for use with externally threaded fasteners which have a plain (nonplated or noncoated) finish or have a plating or coating of insufficient thickness to necessitate overtapping the nut thread to provide assemblability. Zinc-coated nuts are nuts intended for use with externally threaded fasteners which are hot-dip zinc-coated, mechanically zinc-coated, or have a plating or coating of sufficient thickness to necessitate overtapping the nut thread to provide assemblability.

Governing Standards

ASTM A563 Covers the chemical and mechanical requirements for eight grades of carbon and alloy steel nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts.
ASME B18.2.2 Covers the complete general and dimensional data for the various types of inch series square and hex nuts, including machine screw nuts and coupling nuts.
ASME B1.1 UNC & UNF Class 2B Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads.

Grade A Marking
Grade A requires no material marking

Chemical Properties

Per ASTM A563-2015
Grade Material Carbon Manganese Phosphorus Sulfur
% by weight % by weight % by weight % by weight
A Carbon & Alloy Steel 0.55 max - 0.12 0.15 (1)
  1. 1. For Grade A a sulfur content of 0.23 % max is acceptable with the purchasers approval.

Dimensional Specifications

Heavy hex nut dimensions
Per ASME B18.2.2-2015
Nominal Diameter UNC F G H
Width Across Flats Width Across Corners Thickness
Basic Max Min Max Min Basic Max Min
1/4 0.250 20 1/2 0.500 0.488 0.577 0.556 15/64 0.250 0.218
5/16 0.313 18 9/16 0.562 0.546 0.650 0.220 19/64 0.314 0.280
3/8 0.375 16 11/16 0.688 0.669 0.794 0.763 23/64 0.377 0.341
7/16 0.438 14 3/4 0.750 0.728 0.866 0.830 27/64 0.441 0.403
1/2 0.500 13 7/8 0.875 0.850 1.010 0.990 31/64 0.504 0.464
9/16 0.563 12 15/16 0.938 0.909 1.083 1.037 35/64 0.568 0.526
5/8 0.625 11 1 1/16 1.062 1.031 1.227 1.175 39/64 0.631 0.587
3/4 0.750 10 1 1/4 0.250 1.212 1.443 1.382 47/64 0.758 0.710
7/8 0.875 9 1 7/16 1.438 1.394 1.660 1.589 55/64 0.885 0.833
1 1.000 8 1 5/8 1.625 1.575 1.876 1.796 63/64 1.012 0.956
1 1/8 1.125 7 1 13/16 1.812 1.756 2.093 2.002 1 7/64 1.139 1.079
1 1/4 1.250 7 2 2.000 1.380 2.309 2.209 1 7/32 1.251 1.187
1 3/8 1.375 6 2 3/16 2.188 2.119 2.526 2.416 1 11/32 1.378 1.310
1 1/2 1.500 6 2 3/8 2.375 2.300 2.742 2.622 1 15/32 1.505 1.433
1 5/8 1.625 5 1/2 2 9/16 2.562 2.481 2.959 2.828 1 19/32 1.632 1.556
1 3/4 1.750 5 2 3/4 2.750 2.662 3.175 3.035 1 23/32 1.759 1.679
1 7/8 1.875 5 2 15/16 2.938 2.844 3.392 3.242 1 27/32 1.886 1.802
2 2.000 4 1/2 3 1/8 3.125 3.025 3.608 3.449 1 31/32 2.013 1.925
2 1/4 2.250 4 1/2 3 1/2 3.500 3.388 4.041 3.862 2 13/64 2.251 2.155
2 1/2 2.500 4 3 7/8 3.875 3.750 4.474 4.275 2 29/64 2.505 2.401
2 3/4 2.750 4 4 1/4 4.250 4.112 4.907 4.688 2 45/64 2.759 2.647
3 3.000 4 4 5/8 4.625 4.475 5.340 5.102 2 61/64 3.013 2.893
3 1/4 3.250 4 5 5.000 4.838 5.774 5.515 3 3/16 3.252 3.124
3 1/2 3.500 4 5 3/8 5.375 5.200 6.207 5.928 3 7/16 3.506 3.370
3 3/4 3.750 4 5 3/4 5.750 5.562 5.562 6.341 3 11/16 3.670 3.616
4 4.000 4 6 1/8 6.125 5.925 5.925 6.755 3 15/16 4.014 3.862
  1. All dimensions are in inches.