HEX COUPLING NUT DIMENSIONS TABLE

Hex coupling nut dimensions sizes table according to ASME B18.2.2. All dimensions are given in inches.

Hex Coupling Nut Dimensions

Note 1: Nuts shall be furnished without a hole, unless specially ordered by the purchaser. In some applications it may be desirable to assure that the threaded parts joined by a coupling nut are each engaged to approximately one-half nut thickness. As a visual inspection aid, a hole drilled through one side of the nut is recommended. The hole should be located at mid-nut thickness, and have a diameter of 0.2 to 0.4 times nominal nut size for sizes 2 1⁄2 in. and smaller, and 1 in. for sizes 2 3⁄4 in. and larger.

Nominal
 Size		 Basic
Major
Diameter
of
Thread 		 F G H
Width
Across
Flats		 Width
Across
Corners		 Thickness
Hex
Nut
basic min max. min. max. basic min. max.
#6 0.138 5/16 0.302 0.312 0.344 0.361 1/2 0.470 0.510
#8 0.164 5/16 0.302 0.312 0.344 0.361 5/8 0.595 0.645
#10 0.190 5/16 0.302 0.312 0.344 0.361 3/4 0.711 0.760
1/4 0.250 7/16 0.428 0.438 0.488 0.505 1 3/4 1.690 1.760
5/16 0.312 1/2 0.489 0.500 0.557 0.577 1 3/4 1.690 1.760
3/8 0.375 9/16 0.551 0.562 0.628 0.650 1 3/4 1.690 1.760
7/16 0.437 5/8 0.607 0.625 0.692 0.722 1 3/4 1.690 1.760
1/2 0.500 11/16 0.663 0.688 0.756 0.794 1 3/4 1.690 1.760
9/16 0.562 13/16 0.782 0.813 0.891 0.939 2 1/8 2.067 2.135
5/8 0.625 13/16 0.782 0.813 0.891 0.939 2 1/8 2.067 2.135
3/4 0.750 1 0.963 1.000 1.097 1.155 2 1/4 2.190 2.260
7/8 0.875 1 1/4 1.212 1.250 1.382 1.443 2 1/2 2.440 2.510
1 1.000 1 3/8 1.325 1.375 1.511 1.588 2 3/4 2.690 2.760
Nominal
 Size		 Basic
Major
Diameter
of
Thread 		 F G H
Width
Across
Flats		 Width
Across
Corners		 Thickness
Hex
Nut
basic min max. min. max. basic min. max.
1 1/8 1.125 1 1/2 1.450 1.500 1.653 1.732 3 2.940 3.010
1 1/4 1.250  1 5/8 1.575 1.625 1.825 1.876 3 2.940 3.010
1 1/2 1.500 2 1.950 2.000 2.275 2.309 3 1/2 3.440 3.510
1 5/8 1.625 2 9/16 2.481 2.562 2.828 2.959 4 7/8 4.830 4.910
1 3/4 1.750 2 3/4 2.662 2.750 3.035 3.175 5 1/4 5.210 5.290
1 7/8 1.875 2 15/16 2.844 2.938 3.242 3.392 5 5/8 5.580 5.670
2 2.000 3 1/8 3.025 3.125 3.448 3.608 6 5.950 6.040
2 1/4 2.250 3 1/2 3.388 3.500 3.862 4.041 6 3/4 6.700 6.800
2 1/2 2.500 3 7/8 3.750 3.875 4.275 4.474 7 1/2 7.440 7.550
2 3/4 2.750 4 1/4 4.112 4.250 4.688 4.907 8 1/4 8.190 8.310
3 3.000 4.5/8 4.475 4.625 5.101 5.340 9 8.940 9.060
Nominal
 Size		 Basic
Major
Diameter
of
Thread 		 F G H
Width
Across
Flats		 Width
Across
Corners		 Thickness
Hex
Nut
basic min max. min. max. basic min. max.
3 1/4 3.250 5 4.838 5.000 5.515 5.773 9 3/4 9.680 9.810
3 1/2 3.500 5 3/8 5.200 5.375 5.928 6.206 10 1/2 10.430 10.570
3 3/4 3.750 5 3/4 5.562 5.750 6.340 6.639 11 1/4 11.170 11.320
4 4.000 6 1/8 5.925 6.125 6.754 7.072 12 11.920 12.080
4 1/4 4.250 6 1/2 6.288 6.500 7.168 7.506 12 3/4 12.670 12.830
4 1/2 4.500 6 7/8 6.650 6.875 7.581 7.939 13 1/2 13.420 13.580
4 3/4 4.750 7 1/4 7.012 7.250 7.994 8.372 14 1/4 14.160 14.340
5 5.000 7 5/8 7.375 7.625 8.408 8.805 15 14.910 15.090
5 1/4 5.250 8 7.738 8.000 8.821 9.238 15 3/4 15.650 15.850
5 1/2 5.500 8 3/8 8.100 8.375 9.234 9.671 16 1/2 16.400 16.600
5 3/4 5.750 8 3/4 8.462 8.750 9.647 10.104 17 1/4 17.150 17.350
6 6.000 9 1/8 8.825 9.125 10.060 10.537 18 17.890 18.110

Supplements:

Reference:

  • ASME B18.2.2-2010, Square and Hex Nuts (Inch Series)