JIC Fitting Types and What Each One Does

All JIC fittings seal on the same 37° flare; the shape only changes how the line is routed. Here is each type, plus cap and plug sizes.

Last updated October 30, 2026. Reference values; verify against manufacturer specifications.

JIC 37° fittings come in a standard set of shapes: unions, elbows, tees, crosses, bulkheads, swivel adapters, port adapters, caps and plugs. Every one of them uses the same 37° flare seal and the same threads for a given dash size, so the shape only changes how the line is routed. This guide explains each type and what it is used for, then gives a size table for JIC caps and plugs.

JIC fitting types at a glance

Fitting shapes as described in SAE J514 and in manufacturers' 37° flare catalogs. Part codes for each shape differ between manufacturers, so they are not listed here.

Male, female and swivel ends

Every JIC fitting end is one of three kinds. A male end has external threads and a 37° cone on the nose. A female swivel is a nut with internal threads that turns freely on the fitting body and has a 37° seat inside. A tube end is a flared tube held by a tube nut and sleeve; the flare sits against a male cone. A seal always forms between a male cone and either a female seat or a tube flare. For how to tell them apart, see male vs female JIC fittings.

Swivels make assembly easier, because the nut can be tightened without turning the hose or the fitting body. SAE J514 gives female swivels a lower working pressure than rigid ends from -4 upward; the values are on the JIC pressure rating page.

Unions and reducers

A straight union is the simplest JIC fitting: a short body with a male JIC thread and cone at each end. It joins two hoses with female swivels, or two flared tubes. A reducing union has a different dash size at each end, for example -8 to -6. "Reducer" and "expander" are also used for a male-to-female adapter that changes size; check which end is which before ordering, because naming varies.

Elbows, tees and crosses

Elbows are made in 90° and 45° versions. Some have two male ends, and some have one male end and one female swivel. Swivel elbows are often used directly on a hose end or a port adapter to turn the line without a separate union.

Tees come in three main layouts. A union tee has three male ends. A branch tee has a female swivel on the side branch, and a run tee has the swivel in line with one of the male ends. The swivel lets the tee attach directly to an existing male fitting. A cross has four male ends and is less common.

Bulkhead fittings

A bulkhead fitting has a long threaded body and a locknut, so it can be clamped through a hole in a panel, tank wall or frame. Bulkhead unions, elbows and tees exist. The panel hole and locknut size depend on the manufacturer, so take them from the maker's catalog rather than the JIC thread size.

Port adapters

A JIC line rarely connects straight into a component. Most pumps, valves and cylinders have ports with a different thread, so a port adapter goes between them:

• JIC × ORB: male JIC on one end and an SAE O-ring boss stud on the other. The ORB end seals on an O-ring, not the threads. Straight studs are rigid; adjustable studs have a locknut so an elbow or tee can be aimed. See JIC vs ORB.
• JIC × NPTF: the pipe end seals on its tapered thread with sealant; the JIC end must not get sealant. See JIC vs NPT.
• JIC × BSPP or metric: used on European and Asian equipment. The port end usually seals with a bonded washer or O-ring. See JIC vs BSP and the JIC metric conversion chart.
• JIC × ORFS: joins a JIC line to an O-ring face seal fitting. See JIC vs ORFS.

Each end of an adapter can have its own dash number. An adapter listed as "-8 JIC × -6 ORB" has a 3/4-16 JIC end and a 9/16-18 ORB end. The JIC dash size chart explains how dash numbers map to threads.

JIC caps and plugs

A JIC cap is a female nut with a 37° seat that screws onto a male JIC end. A JIC plug is a male cone that screws into a female JIC swivel. Both use the same thread as any other JIC fitting of that dash size. They are used to seal off unused ports and to keep dirt out of open lines during service.

Thread sizes per SAE J514. Male OD is the nominal major diameter; female ID is the approximate value from the Eaton and McGill identification guides. Real threads read slightly under these values.

Plastic dust caps and plugs are sold in the same dash sizes. They protect threads and keep contamination out, but they are not pressure-rated. Use a steel cap or plug on any line that will be pressurised.

A JIC plug is not an ORB plug. An ORB plug has an O-ring under its head and seals in an O-ring boss port, which shares the JIC thread at the same dash. A JIC plug in an ORB port, or an ORB plug in a JIC female, will thread in but will not seal.

Choosing a fitting type

• Use the fewest joints that will route the line. Every extra fitting is another possible leak point.
• Prefer a swivel where a hose would otherwise twist during tightening.
• Use an adjustable port adapter where an elbow must face a set direction.
• Check the material. Steel, stainless steel and brass versions of the same shape are rated differently.
• Confirm the port thread before buying an adapter. The JIC identification guide covers the checks.

The fitting shapes above are defined in SAE J514 (now J514/1); see SAE J514 explained.

References

SAE J514 (fitting shapes and threads); Parker Catalog 4300 Triple-Lok fitting shapes; Eaton Thread Identification Guide and McGill Hose thread identification guide (thread measurements); manufacturer 37° flare catalogs for shape names. Values are reference only.

Frequently asked questions

What are the main types of JIC fittings?

Unions, reducers, elbows (90° and 45°), tees, crosses, bulkheads, swivel adapters, port adapters (to ORB, NPT, BSP, metric and ORFS), caps and plugs.

What is the difference between a JIC cap and a JIC plug?

A cap is a female nut that closes a male JIC end. A plug is a male cone that closes a female JIC swivel.

What size cap fits a -6 JIC fitting?

A -6 JIC cap, which has a 9/16-18 thread and a 37° seat. It fits a male end measuring about 0.56 in (14.3 mm).

What is a branch tee in JIC fittings?

A tee with two male JIC ends and a female swivel on the side branch, so it can be attached directly to an existing male end.

Can I use an ORB plug in a JIC fitting?

No. The threads match at the same dash, but an ORB plug seals with an O-ring in a port and has no 37° cone, so it will not seal in a JIC female.