1.1 Definition and core functions
Hydraulic adapter is used to convert different standard hydraulic interface precision connectors, the main solution:
Compatibility of different thread standards (such as NPT to BSPP)
Interface type conversion (such as flange to thread)
Pipe direction adjustment (e.g. right angle adapters)
1.2 Classification system
Classification by connection standard
| Types | Standards | Characteristics | Typical Applications |
| JIC | SAE J514 | 37° Taper Seal, High Pressure Resistant | Hydraulic Systems for Construction Machinery |
| NPT | ANSI B1.20.1 | Tapered threads, raw-band sealing required | AFSL Industrial Equipment |
| BSPP | ISO 228 | BSP parallel threads, gasket sealing required | European/Asian equipment |
| ORFS | SAE J1926 | Flat O-Ring Seal, Zero Leakage | High-Cleanliness Systems |
Classification by structure
Straight type: coaxial at both ends, used to extend the pipeline
Right-angle type: 90° steering, saving installation space
Three-way / four-way type: shunt hydraulic oil circuit
2.1 Size standard comparison
Nominal size comparison table
| Adapter Number | Corresponding Thread Size | Hose Orifice | Applicable Pressure |
| 4 (JIC4) | 7/16″20 UNF | 1/4″ | 3000 PSI |
| 6 (JIC6) | 9/16″18 UNF | 3/8″ | 4000 PSI |
| 8 (JIC8) | 3/4″16 UNF | 1/2″ | 6000 PSI |
Thread identification techniques
NPT: Tapered threads with decreasing teeth per inch (TPI).
BSPP: Parallel thread with 55° rounded teeth
Metric threads: labeled with “M” (e.g. M16 x 1.5)
2.2 Material Selection Guide
| Material | Pros | Cons | Recommended Scenarios |
| Carbon Steel | Low cost, high strength | Needs plating to prevent rust | General Industrial Equipment |
| Stainless Steel 316 | Corrosion Resistant, Long Life | High Cost | Marine/Food Environments |
| Brass | Conductive, Easy to Work With | Poor Pressure Resistance | Low-Pressure Pneumatic Systems |
3.1 Tools preparation list
1. Torque wrench: precise control of tightening force (recommended range 50200 Nm)
2. Thread sealant: Loctite 545 (resistant to hydraulic oil)
3. Cleaning kit: Lint-free cloth + precision cleaner
4. Anti-seize paste: prevents metal cold welding (e.g. Nickel AntiSeize)
3.2 Key parameters
Raw material tape winding: 2.5 turns clockwise (NPT thread)
Tightening torque (1/2” NPT as an example)
Carbon steel: 3540 Nm
Stainless steel: 3035 Nm (to avoid excessive deformation)
4.1 Corrosion treatment program
Preventive measures
Coastal area: use 316 stainless steel
Regular maintenance: apply antirust grease every 6 months
Storage requirements: Humidity <60% environment
Emergency treatment
1. Mild corrosion: use copper brush to clean and apply antirust paint
2. Severe corrosion:
Soak in penetrating agent (WD40) for 2 hours
Heat to 150℃ and disassemble
Replace damaged parts
Conclusion:
“Hydraulic adapters, though small, are critical to system reliability. It is recommended that an adapter usage file be established to record the model number, torque values and test results for each replacement, which will significantly reduce the risk of unplanned downtime.” — John Carter, Hydraulic System Safety Expert
With this guide, you have a complete body of knowledge from basic theory to real-world purchasing. Specific model selection charts are available upon request by contacting one of our engineers.
(Special customization available, free samples)
China Huiqi (Beijing) Technology Co., Ltd, with fifteen years of excellence, is a professional manufacturer of high quality hydraulic hose fittings, hydraulic hose couplings, hydraulic hose fittings, hydraulic adapters and hydraulic fittings. We offer a wide range of products, including thousands of unique types and sizes of hydraulic fittings, and our comprehensive solutions meet the needs of different industries, ensuring reliable performance and adaptability to a wide range of job requirements.
Our modern manufacturing facility is equipped with 16 automatic CNC lathes and supported by 75 experienced technicians to ensure high precision and consistency in every hydraulic fitting.
Our factory-professional sales team of more than 10 professionals is dedicated to providing exceptional customer service and support. From consultation to post-sale assistance, our team ensures seamless communication, customized solutions and timely responses to meet your unique needs.
What are the main types of our hydraulic fittings:
1, Rings, matching with many kinds of pipes, such as SAE, DIN, EN, GB, etc.
Flat seal fittings, multi-seal fittings, spherical seal fittings, 60°taper seal fittings, 74°taper seal fittings, 24°taper O-ring L.T. fittings, 24°taper O-ring H.T. fittings, JIS 60°taper seal fittings, riser fittings, Japanese metric fittings, etc.;3, British style pipe fittings
3，British style pipe fittings
JIS BSP 60°taper sealing fittings, BSPT fittings, BSP multi-seal fittings, BSP flat sealing fittings, BSP O-ring sealing fittings
4，U.S. Pipe Fitting
NPT nipple, JIC 74°taper sealing nipple, NPSM 60°taper sealing nipple, ORFS flat sealing nipple, SAE O-ring sealing nipple
5, One Piece Fittings
JIC, BSP, Metric, Flange
6, Flange
SAE Code 62 Flanges, SAE Code 61 Flanges, CAT Flanges
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