NPT Tapered Male x ORFS Male Straight Adaptor

NPT tapered one end, O-ring face seal the other. The standard way to get a flat-face ORFS hose onto an American pipe-thread port and off a thread-sealed joint.

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

Watch: Exploring Hydraulic Adaptors Part 1: Difference Between Branch Tee & Run Tee, Elbows Short and Long

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.
• ORFS Male – SAE J1453 O-ring face seal. It seals on an O-ring sitting in the flat face groove, never on the thread.

How to Choose

• The ORFS end seals on the O-ring in the flat face. The NPT end seals on the thread and needs sealant.
• Check the face groove is clean and the ring is seated square before you offer it up.
• ORFS thread callout and line size are different numbers. A 13/16-16 face seal end runs a 1/2" line.

Technicians Advice

If the face seal weeps, look at the O-ring before you touch the spanner. Nine times out of ten it has been nicked going on or left out. Winding a flat face joint tighter just flattens the ring and makes the next attempt harder.

Where You’ll Find It

• NPT Tapered Male – American-built gearboxes, pumps, compressors and older industrial pipework.
• ORFS Male – High-pressure, high-vibration circuits on late-model excavators, drill rigs, crushers and forestry gear.

Cross-Reference

• NPT Tapered Male – ANSI/ASME B1.20.1 tapered pipe thread. The dryseal variant is written NPTF.
• ORFS Male – SAE J1453 / ISO 8434-3 O-ring face seal. Parker call this series Seal-Lok. Also written ORFS or flat face.

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-ORM-0411	11/16" UNO	1/4" NPT	19mm	34mm	Mild steel	Plated finish
NTM-ORM-0611	11/16" UNO	3/8" NPT	19mm	34mm	Mild steel	Plated finish
NTM-ORM-0613	13/16" UNO	3/8" NPT	23.8mm	37mm	Mild steel	Plated finish
NTM-ORM-0809	9/16" UNO	1/2" NPT	23.8mm	42mm	Mild steel	Plated finish
NTM-ORM-0811	11/16" UNO	1/2" NPT	23.8mm	39mm	Mild steel	Plated finish
NTM-ORM-0813	13/16" UNO	1/2" NPT	23.8mm	42mm	Mild steel	Plated finish
NTM-ORM-0816	1" UNO	1/2" NPT	27mm	46mm	Mild steel	Plated finish
NTM-ORM-1213	13/16" UNO	3/4" NPT	31.8mm	42mm	Mild steel	Plated finish
NTM-ORM-1219	1.3/16" UNO	3/4" NPT	31.8mm	49mm	Mild steel	Plated finish
NTM-ORM-1223	1.7/16" UNO	3/4" NPT	38.1mm	51mm	Mild steel	Plated finish
NTM-ORM-1623	1.7/16" UNO	1" NPT	38.1mm	56mm	Mild steel	Plated finish
NTM-ORM-2027	1.11/16" UNO	1.1/4" NPT	44.5mm	58mm	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

🔗 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.