Heavy hex jam nuts are thinner than a standard heavy hex nut but have the same dimension across the flats and corners. Heavy hex jam nuts have two common applications. A heavy hex jam nut can be threaded onto a bolt and run tight against the standard heavy hex nut which will lock the nut in place and prevent it from backing off. Heavy hex jam nuts are sometimes used for leveling purposes as well. Since hot-dip galvanizing typically adds 2.2 to 5 mils of thickness to the threaded portion of a fastener, galvanized heavy hex jam nuts are tapped oversize to compensate for the corrosion resistant coating on the bolts.

Available

Diameters: 1/2″ – 2″
Origin: Import
Finish: Plain and hot-dip galvanized

Dimensions

Click table to show drawingHeavy Hex Jam Nut
Nominal Size F C H Part Numbers
Width Across Flats Width Across Corners Thickness
Basic Max Min Max Min Basic Max Min Plain Galvanized
38 1116 0.688 0.669 0.794 0.763 1564 0.252 0.216 - -
12 78 0.875 0.850 1.010 0.969 1964 0.317 0.277 - -
58 1116 1.062 1.031 1.227 1.175 2364 0.381 0.337 - -
34 114 1.250 1.212 1.443 1.382 2764 0.446 0.398 - 18404
78 1716 1.438 1.394 1.660 1.589 3164 0.510 0.458 - -
1 158 1.625 1.575 1.876 1.796 3564 0.575 0.519 17112 17113
118 11316 1.812 1.756 2.093 2.002 3964 0.639 0.579 - -
114 2 2.000 1.938 2.309 2.209 2332 0.751 0.687 17114 17115
138 21316 2.188 2.119 2.526 2.416 2532 0.815 0.747 - -
112 238 2.375 2.300 2.742 2.622 2732 0.880 0.808 17116 17117
158 2916 2.562 2.481 2.959 2.828 2932 0.944 0.868 - -
134 234 2.750 2.662 3.175 3.035 3132 1.009 0.929 17118 17119
178 21516 2.938 2.844 3.392 3.242 1132 1.073 0.989 - -
2 318 3.125 3.025 3.608 3.449 1332 1.138 1.050 17120 17121
214 312 3.500 3.388 4.041 3.862 11364 1.251 1.155 19847 19846
212 378 3.875 3.750 4.474 4.275 12964 1.505 1.401 - -
234 414 4.250 4.112 4.907 4.688 13764 1.634 1.522 - -
3 458 4.625 4.475 5.340 5.102 14564 1.763 1.643 - -
314 5 5.000 4.838 5.774 5.515 11316 1.876 1.748 - -
312 538 5.375 5.200 6.207 5.928 11516 2.006 1.870 - -
334 534 5.750 5.562 6.640 6.341 2116 2.134 1.990 - -
4 618 6.125 5.925 7.073 6.755 2316 2.264 2.112 - -

Dimensions per ASME B18.2.2 1987 (R 1999)