NPT Tapered Female x UNO O-Ring Boss Male Straight Adaptor

NPT tapered female one end, SAE O-ring boss male the other. Puts an NPT-ended fitting into a UNO port on an American pump, motor or valve bank.

Brand: Ayrtec – mild steel body with a plated finish, manufactured to the standards listed below.

Watch: 90 ° Hydraulic Adaptors How They Work and the Importance of O'Rings

Thread Standards

• NPT Tapered Female – ANSI/ASME B1.20.1 tapered pipe thread. It seals on the thread and needs tape or sealant every time.
• SAE O-Ring Boss Male (UNO/UNF) – SAE J1926 / ISO 11926 straight thread O-ring boss. It seals on an O-ring squeezed against the port spotface, not on the thread.

How to Choose

• The UNO male seals on its O-ring against the port spotface. The NPT female needs sealant on whatever male goes into it.
• A UNO male will start into a BSPP port and strip. Check the full callout, for example 7/8-14.
• Two different sealing methods on one part, so do not treat both ends the same.

Technicians Advice

Get the UNO end seated properly first, then work on the NPT female. Loading a tapered thread while the O-ring is still finding its seat is how both ends end up wrong, and the UNO leak is the one that is hard to spot.

Where You’ll Find It

• NPT Tapered Female – Female side of American pipework, adaptor blocks and gauge manifolds.
• SAE O-Ring Boss Male (UNO/UNF) – Cylinder end caps, pump and valve bosses on US-built plant. Common on Australian-assembled cylinders too, where it is usually called UNO.

Cross-Reference

• NPT Tapered Female – ANSI/ASME B1.20.1 tapered pipe thread.
• SAE O-Ring Boss Male (UNO/UNF) – SAE J1926 / ISO 11926 straight thread O-ring boss. Also written ORB, SAE ORB or UNO. Thread form is UN/UNF.

Parker, Gates, Aeroquip and Ryco all manufacture to these same standards under their own part numbering, so a fitting built to the standard above will mate with theirs.

Cross-references are given at series level as a guide to the standard, not as a part-for-part substitution. Always confirm the thread form, size and seal type against the port before ordering.

Downloads

📄 Thread Identification Chart (PDF)

Same Threads, Other Angles

🔗 90° Compact – same threads

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Need a hand? Call 1300 146 737 or email sales@mhfgc.com.au – real technicians, real answers.