Fittings and Adapters

Which thread is in the pump, the filter or the sensor port – and which hose end does it need to connect to? Fittings and adapters create the transition between AN, NPT, ORB, banjo and metric threads in fuel, oil and cooling systems. This category is for you if you are building or modifying the plumbing in a project.

Thread types and what they are used for

AN fittings seal metal to metal on a 37-degree flare and are typically used on hoses. NPT fittings have tapered pipe threads that seal in the thread itself and normally require thread sealant. ORB fittings seal with an O-ring against a flat face. Banjo fittings provide a low-profile, rotatable connection where space is tight, while bulkhead fittings route a line through a panel or tank. On top of that there are quick-connect couplings and metric adapters.

How to choose the right fitting

Start by determining the connection at both ends, then choose based on several factors:

• Thread and size: find the specification on the component and the hose, e.g. 10AN ORB to 6AN male.
• Angle: straight, 45 or 90 degrees depends on hose routing and available space.
• Medium: check that the fitting and O-rings are designed for fuel, oil or coolant.
• Flow: the inner diameter should match the pump and line – bigger is not automatically better.

At Radium Engineering you will find, for example, adapters from 10AN male to 10AN ORB and banjo fittings in 13.5 and 18.0 mm, while Russell is available with adapter fittings and fuel adapters. Fragola, Vibrant and DeatschWerks are also represented in the category.

Installation and maintenance

Threads that look alike can have different pitches and sealing principles, and the wrong combination can cause leaks or damage the thread. Only use thread sealant where the thread type requires it, and keep it away from the flare and O-ring. Tighten according to the manufacturer's instructions, and check for leaks after the first drive. You will find more connection types under fittings and plugs.

Frequently asked questions

What is the difference between AN and ORB?

AN seals metal to metal on a 37-degree flare and is typically used on hose ends. ORB has straight threads and seals with an O-ring against a flat face, typically in ports on pumps, filters and regulators.

Do all fittings need thread sealant?

No. NPT seals in the thread and normally requires sealant. AN and ORB seal on the flare and O-ring respectively, so sealant is typically unnecessary and can contaminate the system if it comes loose.

How do I find the thread on my component?

Check the component's documentation, or measure the diameter and pitch with a caliper and thread gauge. The AN size indicates the tube diameter in sixteenths of an inch, while metric threads are specified by diameter and pitch in millimetres.

Can I reuse a fitting?

It depends on the type and condition. Check the flare and thread for scratches and deformation, and replace O-rings and seals, e.g. the washers on banjo fittings, once they have been tightened. If in doubt, use new parts.