Fittings & Couplings
Adaptors, elbows, tees, bulkhead fittings, quick-release couplings and the seals that go with them, in BSP, NPT, JIC and SAE. The small parts that decide whether a circuit leaks.
Thread identification is the whole job here. BSP is 55 degrees and comes parallel (BSPP, sealing on a bonded washer or O-ring) or tapered (BSPT, sealing on the thread). NPT is 60 degrees and always tapered. JIC seals on a 37-degree flare and not on the thread at all, so its thread can be tightened hard without ever sealing if the flare face is damaged. SAE O-ring boss seals on an O-ring against a machined face. Four systems, four different sealing mechanisms, and several of them will start into each other.
The practical rule: identify the thread with a gauge or by counting threads per inch and measuring the crest diameter, not by eye. A pitch gauge costs less than one leaked hydraulic charge.
Sourced to order. Send the thread designation on both sides, or photograph the fitting against a rule.
Lines in this category
- BSPP and BSPT adaptors
- NPT adaptors
- JIC 37-degree flare
- SAE O-ring boss
- Elbows and tees
- Bulkhead fittings
- Quick-release couplings
- Bonded seals and O-rings
- Test points
Products
We source this line to order
We do not hold this category in stock, and we would rather say so than list parts we cannot ship. Send a part list, a specification or a photograph and we will quote it with a lead time — this is a line we supply regularly to order.
How to choose
Identify both threads before ordering anything — a pitch gauge and a caliper settle it in seconds and guessing costs a machine down. Then check the sealing mechanism matches on both sides: a parallel thread needs a face to seal against, a tapered thread does not, and putting a bonded washer on a tapered fitting achieves nothing. Then the pressure rating, which for adaptors is usually higher than the hose but not always at the larger sizes. Then the material — steel for hydraulics, brass for air and water, stainless where corrosion matters.
Frequently asked
A fitting starts but will not tighten — what is wrong?
Almost always BSP into NPT or the reverse. The two forms will engage for a couple of turns then bind. Stop and identify both threads properly; forcing it damages the female port, which is a much bigger repair.
Do I need thread tape on a BSPP fitting?
No. BSPP is parallel and seals on a bonded washer or O-ring at the face, not on the thread. Tape on a parallel thread does nothing useful and can shed into the circuit. Tape belongs on tapered threads only.
Can you supply stainless fittings for food or chemical use?
Available to order in 316. State the medium and temperature, since the seal material usually matters more than the body material for compatibility.