Lock Nuts

Lock nuts are available in a lot of different styles, grades, and finishes. As the name indicates, lock nuts cannot be removed once they are fixed. In contrast, we can remove most locknuts and in fact some can be reused if they are correctly removed. Lock nuts come in ASTM A194 Grade 2H as well as ASTM A563 Grades A & DH.

At BBI, we manufacture lock nuts using standard hex or heavy hex pattern. Tri-Lok and Anco tend to be the most commonly used style of lock nuts. Anco style is a self-locking nut that comes with a stainless steel ratchet pin. Once the nut is spun onto the bolt, the pin slides along the threads, eventually preventing the nut from pulling back. Well, the key benefit of using Anco style nuts is that we can bend the ratchet pin in a way that it becomes easy to remove the nut if need arises. Tri-Lok style tends to be the “prevailing-torque” lock nut which acts frictionally resistant to rotation due to thread distortion on the top thread of the nut.
Contact us today for more details on various other types of lock nuts and discuss with our specialized estimators.

Finished Hex Dimensions

Click table to show drawingDimensioned Anco Lock Nut
Nominal Size F C H Weight Each (lbs.)
Width Across Flats Width Across Corners Thickness
Basic Max Min Max Min Basic Max Min
12 34 0.750 0.736 0.866 0.840 716 0.448 0.427 0.04
58 1516 0.938 0.922 1.083 1.051 3564 0.559 0.535 0.07
34 118 1.125 1.088 1.299 1.240 4164 0.665 0.617 0.12
78 1516 1.312 1.269 1.516 1.447 34 0.776 0.724 0.19
1 112 1.500 1.450 1.732 1.653 5564 0.887 0.831 0.28
118 11116 1.688 1.631 1.949 1.859 3132 0.999 0.939 0.40
114 178 1.875 1.812 2.165 2.066 1116 1.094 1.030 0.54
138 2116 2.062 1.994 2.382 2.273 11164 1.206 1.138 0.73
112 214 2.250 2.175 2.598 2.480 1932 1.317 1.245 0.94
Dimensions per ASME B18.2.2 1987 (1999)

Heavy Hex Dimensions

Click table to show drawingDimensioned Anco Lock Nut
Nominal Size F C H Weight Each (lbs.)
Width Across Flats Width Across Corners Thickness
Basic Max Min Max Min Basic Max Min
12 78 0.875 0.850 1.010 0.969 3164 0.504 0.464 0.07
58 1116 1.062 1.031 1.227 1.175 3964 0.631 0.587 0.12
34 114 1.250 1.212 1.443 1.382 4764 0.758 0.710 0.20
78 1716 1.438 1.394 1.660 1.589 5564 0.885 0.833 0.30
1 158 1.625 1.575 1.876 1.796 6364 1.012 0.956 0.43
118 11316 1.812 1.756 2.093 2.002 1764 1.139 1.079 0.59
114 2 2.000 1.938 2.309 2.209 1732 1.251 1.187 0.79
138 2316 2.188 2.119 2.526 2.416 11132 1.378 1.310 1.02
112 238 2.375 2.300 2.742 2.622 11532 1.505 1.433 1.31
158 2916 2.562 2.481 2.959 2.828 11932 1.632 1.556 1.62
134 234 2.750 2.662 3.175 3.035 12332 1.759 1.679 2.04
178 21516 2.938 2.844 3.392 3.242 12732 1.886 1.802 2.41
2 318 3.125 3.025 3.608 3.449 13132 2.013 1.925 2.99
214 312 3.500 3.388 4.041 3.862 21364 2.251 2.155 4.19
212 378 3.875 3.750 4.474 4.275 22964 2.505 2.401 5.64
234 414 4.250 4.112 4.907 4.688 24564 2.759 2.647 7.38
3 458 4.625 4.475 5.340 5.102 26164 3.013 2.893 9.50
314 5 5.000 4.838 5.774 5.515 3316 3.252 3.124 11.94
312 538 5.375 5.200 6.207 5.928 3716 3.506 3.370 15.26
334 534 5.750 5.562 6.640 6.341 31116 3.760 3.616 18.12
4 618 6.125 5.925 7.073 6.755 31516 4.014 3.862 21.80
Dimensions per ASME B18.2.2 1987 (1999)