Heavy hex nuts are slightly larger and thicker than standard (finished) hex nuts. There are numerous grades and the heavy pattern is typically used for large diameter and high strength bolts. See our nut compatibility chart to determine the compatible heavy hex nut(s) for a specific grade of bolt. Since hot-dip galvanizing typically adds 2.2 to 5 mils of thickness to the threaded portion of a fastener, galvanized heavy hex nuts are tapped oversize to compensate for the corrosion-resistant coating on the bolts.

Stock

Diameters: 3/8″ – 2-3/4″
Origin: Domestic and import
Finish: Plain and hot-dip galvanized
Grades: A563 (grades A, C, and DH), A194 grade 2H

Dimensions

Click table to show drawingHeavy Hex Nut
Bolt Diam. F C H Weight
(lbs.)		 Part Numbers
Width Across Flats Width Across Corners Thickness A563A A1942H A563DH
Import Domestic Import Domestic
Basic Max Min Max Min Basic Max Min Plain Galv. Plain Galv. Plain Galv. Plain Galv.
1⁄2 7⁄8 0.875 0.850 1.010 0.969 31⁄64 0.504 0.464 0.07 11729 11730 - - 11761 11762 16356 18345
5⁄8 11⁄16 1.062 1.031 1.227 1.175 39⁄64 0.631 0.587 0.12 11731 11732 16358 16359 11763 11764 - 18346
3⁄4 11⁄4 1.250 1.212 1.443 1.382 47⁄64 0.758 0.710 0.20 11733 11734 16360 16361 11765 11766 - 18347
7⁄8 17⁄16 1.438 1.394 1.660 1.589 55⁄64 0.885 0.833 0.30 11735 11736 16362 16363 11767 11768 - 18348
1 15⁄8 1.625 1.575 1.876 1.796 63⁄64 1.012 0.956 0.43 11737 11738 16364 16365 11769 11770 - 18349
11⁄8 113⁄16 1.812 1.756 2.093 2.002 17⁄64 1.139 1.079 0.59 11739 11740 16366 - 11771 11772 - 16367
11⁄4 2 2.000 1.938 2.309 2.209 17⁄32 1.251 1.187 0.79 11741 11742 16370 - 11773 11774 - 16371
13⁄8 23⁄16 2.188 2.119 2.526 2.416 111⁄32 1.378 1.310 1.02 11743 11744 16374 - 11775 11776 - 16375
11⁄2 23⁄8 2.375 2.300 2.742 2.622 115⁄32 1.505 1.433 1.31 11745 11746 16378 - 11777 11778 - 16379
15⁄8 29⁄16 2.562 2.481 2.959 2.828 119⁄32 1.632 1.556 1.62 17750 17751 16380 16381 11779 11780 16380 16381
13⁄4 23⁄4 2.750 2.662 3.175 3.035 123⁄32 1.759 1.679 2.04 11747 11748 16384 16385 12549 12550 16384 16385
17⁄8 215⁄16 2.938 2.844 3.392 3.242 127⁄32 1.886 1.802 2.41 19433 19434 - - - - - -
2 31⁄8 3.125 3.025 3.608 3.449 131⁄32 2.013 1.925 2.99 11749 11750 16390 16391 11783 11784 16390 16391
21⁄4 31⁄2 3.500 3.388 4.041 3.862 213⁄64 2.251 2.155 4.19 11751 11752 16396 16397 12681 12682 16396 16397
21⁄2 37⁄8 3.875 3.750 4.474 4.275 229⁄64 2.505 2.401 5.64 11753 11754 16398 16399 12553 12554 16398 16399
23⁄4 41⁄4 4.250 4.112 4.907 4.688 245⁄64 2.759 2.647 7.38 15864  16041 16400 16401 12555 12556 16400 16401
3 45⁄8 4.625 4.475 5.340 5.102 261⁄64 3.013 2.893 9.50 15863 16042 16402 16403 12601 12602 16402 16403
31⁄4 5 5.000 4.838 5.774 5.515 33⁄16 3.252 3.124 11.94 18395 - - - - - - -
31⁄2 53⁄8 5.375 5.200 6.207 5.928 37⁄16 3.506 3.370 15.26 18495 - - - - - - -
33⁄4 53⁄4 5.750 5.562 6.640 6.341 311⁄16 3.760 3.616 18.12 - - - - - - - -
4 61⁄8 6.125 5.925 7.073 6.755 315⁄16 4.014 3.862 21.80 11755 11756 16404 16405 - - 16404 16405

Dimensions per ASME B18.2.2 1987 (1999)