Also known as hex couplers, hex coupling nuts are used to bridge two different pieces of threaded material. Both hex & heavy hex couplers seem to be threaded right hand. It is ideal to use a sleeve nut if there is need for a right hand-left hand coupler.

Stock

Diameters: 1/2″ – 1″
Origin: Domestic and import
Finish: Plain and hot-dip galvanized
Grades: A563 (grades A and DH)

Available

Diameters: 1/2″ – 6″
Origin: Domestic and import
Finish: Plain and hot-dip galvanized
Grades: A563 (grades A, C, and DH), A194 grade 2H

Dimensions

Finished Hex Coupler Pattern

Click table to show drawingHex Coupling Nut
Nominal Size F C H Part Numbers
Width Across Flats Width Across Corners Length/Thickness Import
Basic Max Min Max Min Basic Max Min Plain Galvanized
1⁄2 11⁄16 0.688 0.663 0.794 0.756 13⁄4 1.760 1.690 12338 17525
5⁄8 13⁄16 0.813 0.782 0.939 0.891 21⁄8 2.135 2.067 12559 18195
3⁄4 1 1.000 0.963 1.155 1.097 21⁄4 2.260 2.190 12557 17526
7⁄8 11⁄4 1.250 1.212 1.443 1.382 21⁄2 2.510 2.440 12558 19504
1 13⁄8 1.375 1.325 1.588 1.511 23⁄4 2.760 2.690 - 18494
11⁄8 11⁄2 1.500 1.450 1.732 1.653 3 3.010 2.940 18394 -
11⁄4 15⁄8 1.625 1.575 1.876 1.825 3 3.010 2.940 18994 17529
11⁄2 2 2.000 1.950 2.309 2.275 31⁄2 3.510 3.440 - -
Dimensions per ASME B18.2.2 2010
Some dimensions may vary by supplier

Heavy Hex Coupler Pattern

Click table to show drawingHex Coupling Nut
Nominal Size F C H Part Numbers
Width Across Flats Width Across Corners Thickness A563DH Domestic
Basic Max Min Max Min Basic Max Min Plain Galvanized
1⁄2 7⁄8 0.875 0.850 1.010 0.969 11⁄2 - - - -
5⁄8 11⁄16 1.062 1.031 1.227 1.175 17⁄8 - - 17543 17544
3⁄4 11⁄4 1.250 1.212 1.443 1.382 21⁄4 - - - 17527
7⁄8 17⁄16 1.438 1.394 1.660 1.589 25⁄8 - - - -
1 15⁄8 1.625 1.575 1.876 1.796 3 - - - 12343
11⁄8 113⁄16 1.812 1.756 2.093 2.002 33⁄8 - - - -
11⁄4 2 2.000 1.938 2.309 2.209 33⁄4 - - 17547 17548
11⁄2 23⁄8 2.375 2.300 2.742 2.622 41⁄2 - - 17551 17552
15⁄8 29⁄16 2.562 2.481 2.959 2.828 47⁄8 4.91 4.83 - -
13⁄4 23⁄4 2.750 2.662 3.175 3.035 51⁄4 5.29 5.21 17553 17554
17⁄8 215⁄16 2.938 2.844 3.392 3.242 55⁄8 5.67 5.58 - -
2 31⁄8 3.125 3.025 3.608 3.449 6 6.04 5.95 17555 17556
21⁄4 31⁄2 3.500 3.388 4.041 3.862 63⁄4 6.80 6.70 - -
21⁄2 37⁄8 3.875 3.750 4.474 4.275 71⁄2 7.55 7.44 - -
23⁄4 41⁄4 4.250 4.112 4.907 4.688 81⁄4 8.31 8.19 - -
3 45⁄8 4.625 4.475 5.340 5.102 9 9.06 8.94 - -
31⁄4 5 5.000 4.838 5.774 5.515 93⁄4 9.81 9.68 - -
31⁄2 53⁄8 5.375 5.200 6.207 5.928 101⁄2 10.57 10.43 - -
33⁄4 53⁄4 5.750 5.562 6.640 6.341 111⁄4 11.32 11.17 - -
4 61⁄8 6.125 5.925 7.073 6.755 12 12.08 11.92 - -
41⁄2 67⁄8 6.875 6.650 7.939 7.581 131⁄2 - - - -
5 75⁄8 7.625 7.375 8.805 8.408 15 - - - -
Heavy coupler dimensions are not defined by ASME 18.2.2. The width across the flats and corners match the dimensions of a heavy hex nut.