ANSI (inch) Hex and Jam Nut Size Table Chart

Hardware ANSI Menu

The following tables provide Hex Nut and Jam Nut dimensions per ASME / ANSI B18.2.2.

American National Standard and Unified Standard Hex Nuts and Jam Nuts and Heavy Hex Nuts and Jam Nuts

ASME B18.2.2 Hex Nut
Hex Nut

Hex Jam Nut

Hex Jam Nut

Nominal Size
or
Basic Major
Dia. of Thread
Width Across
Flats F
Width Across
Corners G
Thickness,
Nuts H
Thickness,Jam
Nuts Hl
Basic
Max.
Min.
Max.
Min.
Basic
Max.
Min.
Basic
Max.
Min.
1/4
0.2500
7/16
0.438
0.428
0.505
0.488
7/32
0.226
0.212
5/32
0.163
0.150
5/16
0.3125
1/2
0.500
0.489
0.577
0.557
17/64
0.273
0.258
3/16
0.195
0.180
3/8
0.3750
9/16
0.562
0.551
0.650
0.628
21/64
0.337
0.320
7/32
0.227
0.210
7/16
0.4375
11/16
0.688
0.675
0.794
0.768
3/8
0.385
0.365
1/4
0.260
0.240
1/2
0.5000
3/4
0.750
0.736
0.866
0.840
7/16
0.448
0.427
5/16
0.323
0.302
9/16
0.5625
7/8
0.875
0.861
1.010
0.982
31/64
0.496
0.473
5/16
0.324
0.301
5/8
0.6250
15/16
0.938
0.922
1.083
1.051
35/64
0.559
0.535
3/8
0.387
0.363
3/4
0.7500
11/8
1.125
1.088
1.299
1.240
41/64
0.665
0.617
27/64
0.446
0.398
7/8
0.8750
15/16
1.312
1.269
1.516
1.447
3/4
0.776
0.724
31/64
0.510
0.458
1
1.0000
11/2
1.500
1.450
1.732
1.653
55/64
0.887
0.831
35/64
0.575
0.519
1 1/8
1.1250
1 11/16
1.688
1.631
1.949
1.859
31/32
0.999
0.939
39/64
0.639
0.579
1 1/4
1.2500
1 7/8
1.875
1.812
2.165
2.066
11/16
1.094
1.030
23/32
0.751
0.687
1 3/8
1.3750
2 1/16
2.062
1.994
2.382
2.273
1 11/64
1.206
1.138
25/32
0.815
0.747
1 1/2
1.5000
2 1/4
2.250
2.175
2.598
2.480
1 9/32
1.317
1.245
27/32
0.880
0.808
1/4
0.2500
1/2
0.500
0.488
0.577
0.556
15/64
0.250
0.218
11/64
0.188
0.156
5/ 16
0.3125
9/16
0.562
0.546
0.650
0.622
19/64
0.314
0.280
13/64
0.220
0.186
3/8
0.3750
11/16
0.688
0.669
0.794
0.763
23/64
0.377
0.341
15/64
0.252
0.216
7 /16
0.4375
3/4
0.750
0.728
0.866
0.830
27/64
0.441
0.403
17/64
0.285
0.247
1/2
0.5000
7/8
0.875
0.850
1.010
0.969
31/64
0.504
0.464
19/64
0.317
0.277
9 /16
0.5625
1 5/16
0.938
0.909
1.083
1.037
35/64
0.568
0.526
21/64
0.349
0.307
5/8
0.6250
1 1/16
1.062
1.031
1.227
1.1175
39/64
0.631
0.587
23/64
0.381
0.337
3/4
0.7500
1 1/4
1.250
1.212
1.443
1.382
47/64
0.758
0.710
27/64
0.446
0.398
7/8
0.8750
1 7/16
1.438
1.394
1660
1.589
55/64
0.885
0.833
31/64
0.510
0.458
1
1.0000
1 5/8
1.625
1.575
1.876
1.796
63/64
1.012
0.956
35/64
0.575
0.519
1 1/8
1.1250
1 13/16
1.812
1.756
2.093
2.002
1 7/64
1.139
1.079
39/64
0.639
0.579
1 1/4
1.2500
2
2.000
1.938
2.309
2.209
1 7/32
1.251
1.187
23/32
0.751
0.687
1 3/8
1.3750
2 3/16
2.188
2.119
2.526
2.416
1 11/32
1.378
1.310
25/32
0.815
0.747
1 1/2
1.5000
2 3/8
2.375
2.300
2.742
2.622
1 15/32
1.505
1.433
27/32
0.880
0.808
1 5/8
1.6250
2 9/16
2.562
2.481
2.959
2.828
1 19/32
1.632
1.556
29/32
0.944
0.868
1 3/4
1.7500
2 3/4
2.750
2.662
3.175
3.035
1 23/32
1.759
1.679
31/32
1.009
0.929
1 7/8
1.8750
2 15/16
2.938
2.844
3.392
3.242
1 27/32
1.886
1.802
11/32
1.073
0.989
2
2.0000
3 1/8
3.125
3.025
3.608
3.449
1 31/32
2.013
1.925
13/32
1.138
1.050
2 1/4
2.2500
3 1/2
3.500
3.388
4.041
3.862
2 13/64
2.251
2.155
1 13/64
1.251
1.155
2 1/2
2.5000
3 7/8
3.875
3.750
4.474
4.275
2 29/64
2.505
2.401
1 29/64
1.505
1.401
2 3/4
2.7500
4 1/4
4.250
4.112
4.907
4.688
2 45/64
2.759
2.647
1 37/64
1.634
1.522
3
3.0000
4 5/8
4.625
4.475
5.340
5.102
2 61/64
3.013
2.893
1 45/64
1.763
1.643
3 1/4
3.2500
5
5.000
4.838
5.774
5.515
3 3/16
3.252
3.124
1 13/16
1.876
1.748
3 1/2
3.5000
53/8
5.375
5.200
6.207
5.928
3 7/16
3.506
3.370
1 15/16
2.006
1.870
3 3/4
3.7500
53/4
5.750
5.562
6.640
6.341
3 11/16
3.760
3.616
2 1/16
2.134
1.990
4
4.0000
61/8
6.125
5.925
7.073
6.755
3 15/16
4.014
3.862
2 3/16
2.264
2.112

All dimensions are in inches.