How it connects
A captive female swivel rotates onto the male thread without twisting the hose. Tightening compresses the internal gasket against the mating end; the straight threads provide retention rather than a tapered thread seal.
Male and female halves
This is the female, internally threaded swivel half; its mate is an externally threaded male NH/NST end. Both nominal size and thread designation must match.
Usually connects to
- Male NH/NST fire-hose connection of the same nominal size
Common sizes
- The sample is nominal 1-1/2 inch; 1-1/2 inch NH has 9 threads per inch. Other listed NH swivel sizes include 2, 2-1/2, 4 and 6 inches. Nominal hose size is not the measured thread diameter.
Where it is used
Fire-hose connectionsFire hydrantsPumps, valves and standpipes
Variations
- Pin-lug female swivel
- Double female swivel adapter
- Female NH swivel to another thread or hose termination
How to recognise it
Look for internal threads in a rotating collar, a gasket at the inner shoulder, and often external pin or rocker lugs. Confirm NH/NST markings and nominal size; swivel construction alone cannot identify the thread standard. For the sample size, verify 9 TPI.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| NPSH / IPT hose thread | Also straight and gasket-sealed, but has pipe-thread dimensions and pitch. NH/NST requires a matching NH/NST mate; check designation, diameter and pitch. |
| NPT pipe thread | NPT is tapered; NH/NST is straight and uses a female gasket. They are different interfaces. |
| Garden hose thread | Garden-hose ends mate with garden-hose threads, not NH/NST. Confirm markings and thread measurements instead of relying on the presence of a swivel. |
Also called
Female NH swivelFemale NST swivelFemale National Hose Thread coupling
Good to know
NH and NST are synonyms here. Pin lugs and the swivel describe coupling construction; the hose shank is a separate interface.
Related connections
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