NPT Tapered Male x SAE O-Ring Boss Male 90° Compact Elbow

O-ring boss into the port, NPT male out to pipework, turned 90°. Common on American plant where a boss port has to feed into older NPT plumbing.

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 Male – ANSI/ASME B1.20.1 tapered pipe thread. It seals on thread interference, so tape or sealant is a must.
• 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 ORB end needs a machined boss with a spotface. NPT ports are tapered and are not a substitute.
• Tape or sealant on the NPT end only.
• Take the O-ring size from the port - boss O-rings are consumable and often missing.

Technicians Advice

Wind the ORB end in until the O-ring just touches, then nip by feel. Overtightening extrudes it into the thread and it seeps within a shift. The NPT end is the opposite and wants real torque plus sealant.

Where You’ll Find It

• NPT Tapered Male – American-built gearboxes, pumps, compressors and older industrial pipework.
• 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 Male – ANSI/ASME B1.20.1 tapered pipe thread. The dryseal variant is written NPTF.
• 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.

📐Dimensions & thread sizes – every size in this range

← Swipe the table sideways to see every measurement →

Part code	A	B	H1	S1	Material	Finish
NTM-UNM-90C-0407	7/16" UNO	1/4" NPT	14.3mm	14.3mm	Mild steel	Plated finish
NTM-UNM-90C-1217	1.1/16" UNO	3/4" NPT	25.4mm	27.0mm	Mild steel	Plated finish

Key: H1 centre to face 2, S1 hex across flats 2. Measurements in millimetres unless shown otherwise. Thread columns show what each end mates with. Dimensions are nominal – check critical clearances against the part.

Downloads

📄 Thread Identification Chart (PDF)

Same Threads, Other Angles

🔗 Straight – same threads

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