Threads for Quick Couplings

Quick couplings can be used in hydraulic systems or liquid transmission lines and can be disconnected and connected at any time, so they are prevalent in various industries. In quick couplings, threads are often used to connect hoses, pipes, or tubes. Because it is often used to connect hoses, the most common threads are pipe threads, for example, NPT in North America and European imperial BSPP.

Female Pipe Threads

Most hydraulic quick couplings use female pipe thread threads, usually male threads on the hose end, and female threads on the quick coupling. For some special applications, metric threads with seals are also used.

female pipe thread ig 1
Thread Type Standard
NPT ANSI B1.20.3
BSP ISO 228/1
Rc(BSPT) ISO 7/1
Metric Threads ISO 6149-1
female pipe thread SAE ig 2
Thread Type Standard
UN/UNF SAE J1926-1

Male Threads

The use of external threads in quick connectors will be less, and there are also special external threads in some quick connectors, such as the HJP/HJB series, and high-pressure quick connectors for hydraulic tools. Customers will also require the use of external threads in some quick connectors, and we will produce threads according to customer needs.

Male UN 37˚ flared connectors long
Thread Type Standard
BSP Male Thread DIN 3852-2
Male UN 37˚ flared connectors long
Thread Type Standard
NPT ANSI B1.20.1
BSPT(R) EN 10226-2
Male UN 37˚ flared connectors long
Thread Type Standard
BSP Male Thread seal DIN 3852-2
male thread with o-ring
Thread Type Standard
UN/UNF 2A ISO 11926-3
Metric Threads ISO 6149-2
male 60˚ cone end DIN 7631
Thread Type Standard
60˚ Cone connector bulkhead ISO 8434-2
female pipe thread ig 1
Thread Type Standard
37˚ flared connector ISO 8434-2
Male UN 37˚ flared connectors long
Thread Type Standard
37˚ Flared connector bulkhead ISO 8434-2
Male UN 37˚ flared connectors long
Thread Type Standard
24° cone connectors ISO 8434-1
Male UN 37˚ flared connectors long
Thread Type Standard
24° cone connectors bulkhead ISO 8434-1
Male UN 37˚ flared connectors long
Thread Type Standard
O-ring face seal fitting ISO 8434-3
Male UN 37˚ flared connectors long
Thread Type Standard
O-ring face seal fitting bulkhead ISO 8434-3

Tapered threads

AG 7 50x50 1

Tapered threads are the most common type of thread available. As the name implies, they have a slight taper. When mated together and tightened, the threads compress to form a seal. The mating threads both hold the fitting in place and seal the connection. The most widely used pipe threads in North America are NPT (National Pipe Taper). And in other countries, they also use BSPT (British Standard Pipe Taper).

NPTF (Dryseal) threads are modified NPT threads, which are less likely to leak without a sealant. For a leak-free seal, we recommend using a sealant compound or PTFE tape. You can use NPTF threads with NPT threads, but you’ll lose some of the leak-free characteristics.

Straight threads

AG 5 50x50 1Straight (parallel) threads are used for mechanical joining. They serve one purpose – to hold a fitting in place. As a result, an O-ring (elastomer), hard metal seal, or a soft seat seal is required. When used together, the threads and sealing method provide a better overall seal than tapered threads. Straight pipe threads include NPSM (National Pipe Straight Mechanical), NPSL (National Pipe Straight Locknut) and NPSH (National Pipe Straight Hose) conform to SAE (Society of Automotive Engineers specifications. Sizing and pitches differ from the NPT threads