Frequently Asked Question
Can coupling nuts be made in custom lengths?
Hex and heavy hex coupling nuts can be made in custom lengths. Depending on the size and grade, however, there may be an extended lead time associated with doing that. Off-the-shelf coupling nut lengths have fairly few options for a given diameter. As long as the coupling nut is long enough to achieve the desired thread engagement, the lack of length options may not be an issue. However, there are certain applications where the coupling nut will need to be longer than standard. In this case, the coupling nut will need to be custom machined, and if made to a higher strength grade, such as A194 2H or A563 DH, will then need to go through a heat treating process.
Below are two charts detailing the standard dimensions of coupling nuts per ASME B18.2.2 2010, which should be readily available in the marketplace. If the coupling nut that you are looking for is longer than what is shown, it will likely need to be custom manufactured. Custom coupling nuts with larger or smaller hex dimensions as well as galvanized coatings can also be manufactured. Contact Portland Bolt for any of your coupling nut requirements and the fasteners that are being coupled together.
Finished Hex Coupler Dimensions
| 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 | ||||||||||
Heavy Hex Coupler Dimensions
| 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 | - | - | 17541 | 17542 |
| 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 | - | - | 17528 | 17527 |
| 7⁄8 | 17⁄16 | 1.438 | 1.394 | 1.660 | 1.589 | 25⁄8 | - | - | 19501 | 19502* |
| 1 | 15⁄8 | 1.625 | 1.575 | 1.876 | 1.796 | 3 | - | - | 12344 | 12343 |
| 11⁄8 | 113⁄16 | 1.812 | 1.756 | 2.093 | 2.002 | 33⁄8 | - | - | 12348 | 12349 |
| 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. * 7/8" Galvanized Couplers are 3" long. | ||||||||||
Hello –
I am looking for a specific pipe coupling that is female on both ends. If no such thing is available for sale – then I would be interested to have it custom manufactured.
I need: Pipe Fitting 1/4″ NPT to Metric Female M7 M7X1
The coupling (fitting) would be very short – just long enough for a male end to screw into each side. I am basically just trying to fix two different things together that have the two separate male end measurements.
Is this something you could help me with, or that we could discuss? Thank you very much!!
Willem
@Willem- Apologies, but this part doesn’t fall under the realm of fastener that we can help with.
Can you make CNs using square or rectangular bar stock?
@Tim- We could likely do that, yes. We would need drawing with your specific needs, and then, if it is a feasible part, we could provide you with a formal quote.
are you able to do coupling nuts with different thread pitch on each side of coupler ?
kinda of like a reducer idea.
@Ron- We are able to have couplers like that specially made, but they aren’t anything we inventory.