BSP and JIC hydraulic fittings are not directly interchangeable. They use different thread systems and, more importantly, do not share one universal sealing interface.
A JIC connection uses straight UN or UNF threads to pull a male and female 37-degree flare together. The threads provide the clamping force, while the two 37-degree surfaces create the seal.
BSP is a broader pipe-thread family rather than one fixed fitting design. BSPP uses a parallel 55-degree Whitworth thread and may seal with a bonded washer, O-ring, machined face, or 60-degree cone. BSPT uses tapered 55-degree threads and normally seals within the threaded joint with a suitable thread sealant.
JIC stands for Joint Industry Council. In modern hydraulic specifications, JIC fittings are associated with the SAE J514 37-degree flare connection.
A JIC male fitting has a 37-degree conical nose and a straight UN or UNF thread. The female side contains a matching 37-degree flare seat, often inside a swivel nut. When assembled correctly, the threads draw the two flare surfaces together and the metal-to-metal seat forms the pressure seal.
This distinction matters during identification. The straight thread is not the sealing surface, so applying PTFE tape to a JIC thread does not repair a damaged or mismatched flare. Leaks are more likely to come from scratches, contamination, deformation, misalignment, an incorrect seat angle, or insufficient engagement at the 37-degree interface.
JIC connections are widely used on hydraulic hoses, rigid tubing, adapters, valves, cylinders, agricultural machinery, construction equipment, and industrial systems. Their working pressure is not determined by the JIC name alone. The fitting size, material, wall section, manufacturing specification, mating component, and complete hose or tube assembly must all be considered.
JIC should also be distinguished from SAE 45-degree flare, JIS 30-degree flare, and other cone connections that may have similar-looking threads or seats.
Dash | Thread | Threads Pre | Female Thread | Male Thread |
-2 | 5/16 | 24 | 6.7 | 7.9 |
-3 | 3/8 | 24 | 8.3 | 9.5 |
-4 | 7/16 | 20 | 9.9 | 11.1 |
-5 | 12 | 20 | 11.5 | 12.7 |
-6 | 9/16 | 18 | 12.7 | 14.3 |
8 | 3/4 | 16 | 17.5 | 19.1 |
-10 | 7/8 | 14 | 20.6 | 22.2 |
-12 | 1-1/16 | 12 | 24.6 | 27.0 |
-14 | 1-3/16 | 12 | 28.2 | 30.2 |
-16 | 1-5/16 | 12 | 31.4 | 33.3 |
-20 | 1-5/8 | 12 | 39.3 | 41.3 |
-24 | 1-7/8 | 12 | 45.6 | 47.6 |
-32 | 2-1/2 | 12 | 61.5 | 63.5 |
JIC hydraulic fittings size chart
BSP stands for British Standard Pipe. Unlike JIC, the term BSP does not identify one universal sealing surface. It describes a family of pipe threads with a 55-degree Whitworth form and rounded crests and roots.
BSPP, commonly designated G, uses parallel threads. Under ISO 228, the threads hold the components together but are not intended to create pressure-tightness along the thread. The connection must seal at another surface. Depending on the fitting design, this may be a bonded washer, O-ring, flat port face, or 60-degree cone seat.
BSPT belongs to the ISO 7 pressure-tight thread system. An R tapered external thread may mate with a compatible Rp parallel internal thread or Rc tapered internal thread. In this connection, pressure-tightness is developed within the threaded joint, and a suitable thread sealant is normally required.
A BSP thread designation therefore needs supporting information. A description such as “G1/2 male with bonded seal” or “G1/2 female swivel with 60-degree cone” is more useful than “1/2 BSP.” Two fittings can have the same G thread and still be incompatible if their sealing faces do not match.
Thread | Threads | Pitch | Major diameter | |
Mm | Inch | |||
1/16 | 28 | 0.907 | 7.723 | 0.304 |
1/8 | 28 | 0.907 | 9.728 | 0.383 |
1/4 | 19 | 1.337 | 13.157 | 0.518 |
3/8 | 19 | 1.337 | 16.662 | 0.656 |
1/2 | 14 | 1.814 | 20.995 | 0.825 |
5/8 | 14 | 1.814 | 22.911 | 0.902 |
3/4 | 14 | 1.814 | 26.441 | 1.041 |
1 | 11 | 2.309 | 33.249 | 1.309 |
1 1/4 | 11 | 2.309 | 41.91 | 1.65 |
1 1/2 | 11 | 2.309 | 47.803 | 1.882 |
2 | 11 | 2.309 | 59.614 | 2.347 |
2 1/2 | 11 | 2.309 | 75.184 | 2.96 |
3 | 11 | 2.309 | 87.884 | 3.46 |
4 | 11 | 2.309 | 113.03 | 4.45 |
5 | 11 | 2.309 | 138.43 | 5.45 |
6 | 11 | 2.309 | 163.83 | 6.45 |
BSP hydraulic fittings size chart
Feature | JIC | BSP |
Main definition | 37° flare connection | Family of 55° pipe threads |
Common standard | SAE J514 | ISO 228-1 or ISO 7-1 |
Thread form | Straight UN/UNF | Parallel G or R/Rp/Rc jointing threads |
Thread angle | 60° UN thread form | 55° Whitworth thread form |
Primary seal | 37° metal-to-metal flare | Depends on BSP connection type |
Common BSPP seals | Not applicable | Washer, O-ring, face or 60° cone |
Common BSPT seal | Not applicable | Tapered threaded joint with sealant |
Thread sealant | Not used to seal the JIC flare | Used for conventional BSPT; not a substitute for BSPP face seals |
Direct interchangeability | No | No |
Pressure rating | Depends on exact part and assembly | Depends on exact part and assembly |
Start by locating the sealing surface. A JIC connection has a clearly defined 37-degree flare. A BSP fitting may have a bonded-seal shoulder, O-ring, flat face, 60-degree cone, or tapered pipe thread.
Next, determine whether the thread is parallel or tapered. JIC threads are straight. BSPP threads are also straight, while an R or Rc BSPT thread is tapered. Because both JIC and BSPP are parallel, thread shape alone cannot distinguish them.
Measure the male thread outside diameter with calipers and use a thread-pitch gauge to determine the threads per inch. Compare both measurements with the appropriate JIC and BSP reference tables. Never identify a thread from diameter alone; several nominal sizes can appear close when measured with a ruler.
Then inspect the thread profile and seat. JIC uses a 60-degree UN thread form but seals on a 37-degree flare. BSP uses a 55-degree Whitworth thread form with rounded crests and roots, while the sealing interface depends on the BSP connection design.
Follow this sequence:
1. Identify male or female thread.
2. Check whether the thread is parallel or tapered.
3. Measure the diameter.
4. Measure the threads per inch.
5. Inspect the sealing face or cone.
6. Compare the complete result with the drawing or thread chart.
7. Confirm the mating component before installation.
Manufacturer markings, hex grooves, equipment origin, and existing part numbers can support identification, but they should not replace dimensional verification.
Diameter
When it comes to measuring the diameter of JIC fittings, precision is key. Utilize calipers to measure the outer diameter of the male thread or the inner diameter of the female thread. This step is crucial for ensuring that the fitting will properly connect with its corresponding component, thereby preventing any potential leaks or system failures.
Thread Count
Thread count is another vital metric. To determine the thread pitch, count the number of threads within an inch. This information is essential for compatibility, especially when you’re dealing with high-pressure hydraulic systems where even a minor mismatch can lead to significant issues.
Flare Angle
The flare angle is a defining characteristic of JIC fittings. Use a specialized angle gauge to confirm the 37-degree flare angle. This is especially important in high-pressure applications where a secure, leak-proof connection is paramount.
Diameter
Just like with JIC fittings, the diameter is a critical measurement for BSP fittings. Use calipers to measure the major diameter of the male thread or the inner diameter of the female thread. Accurate measurement ensures that the fitting will seamlessly integrate into your hydraulic system.
Thread Count
BSP thread pitch is generally measured in threads per inch (TPI). To accurately determine this, use a thread gauge. Knowing the correct TPI is essential for ensuring that the BSP fitting will be compatible with other components in the system.
Thread Angle
BSP fittings have a unique 55-degree thread angle. Confirm this angle using an angle gauge to ensure you have the right type of fitting. This is particularly important in applications requiring a secure, leak-proof connection.
Type
BSP fittings come in two main types: BSPP (parallel) and BSPT (tapered). To determine which type you have, use a parallel or tapered gauge. This is crucial because each type has its own set of applications and compatibility requirements.
BSP and JIC should not be selected by asking which one is universally stronger, cheaper, or more reliable. The correct connection is the one that matches the existing equipment, mating component, sealing method, and verified operating requirements.
Use JIC when the mating component is specified for a 37-degree flare connection with the corresponding UN or UNF thread. Use BSP only after confirming whether the system requires BSPP or BSPT and identifying the exact sealing interface.
For imported equipment, the manufacturing region may provide a clue, but it is not proof. A European machine may contain SAE connections, while a North American assembly may use BSP adapters on imported components.
When transitioning between standards, use a purpose-designed adapter. The specification should identify both ends independently, for example:
– G1/2 male with bonded seal × -8 JIC male
– R1/2 male BSPT × -8 JIC male
– G3/4 female swivel with 60-degree cone × -12 JIC male
Before approval, verify working pressure, temperature, fluid compatibility, material, coating, orientation, available installation space, and the rating of the complete assembly.
A BSP-to-JIC request should identify both connection ends completely. A description such as “1/2 BSP to JIC adapter” does not provide enough information for production or cross-reference approval.
Provide:
– BSPP or BSPT designation
– G, R, Rp, or Rc callout
– BSP nominal size
– BSP sealing face or seal type
– JIC dash size
– JIC male or female configuration
– Fitting shape and orientation
– Material and surface finish
– Fluid, temperature, and working pressure
– Quantity by part number
– Drawing, sample, catalog reference, or clear photographs
– Packaging and identification requirements
Topa can review multi-SKU BSP, JIC, and transition-adapter lists for distributor replenishment, OEM applications, and recurring supply. Final interchangeability should be based on the complete connection dimensions and sealing surfaces, not on a similar part number or visual appearance.
Identify the complete connection before choosing a replacement or adapter. For BSP, confirm BSPP or BSPT and the actual seal design. For JIC, confirm the dash size, thread and 37-degree flare. Then verify the exact fitting’s material, dimensions, pressure rating and mating component.
BSP stands for British Standard Pipe, a type of thread commonly used in hydraulic and plumbing systems in the UK and other countries.
JIC stands for Joint Industry Council, a standard for hydraulic fittings primarily used in the United States with a 37-degree flare connection.
The main difference is that BSP fittings have a parallel or tapered thread, while JIC fittings have a 37-degree flare for sealing.
No. BSP and JIC use different thread forms and sealing interfaces. A purpose-designed adapter is required to connect the two systems.
JIC is a 37-degree flare connection using straight UN or UNF threads. BSP is a family of 55-degree pipe threads that may be parallel or tapered and may use several different sealing methods.
Yes, BSP fittings can be used in high-pressure systems, but proper sealing techniques must be applied to ensure leak-free connections.
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