BSP Tapered Male x UNO O-Ring Boss Male Straight Adaptor

BSP tapered one end, SAE O-ring boss the other. The standard way to get a BSPT line into the UNO ports on American pumps, valves and cylinders without cutting anything about.

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

• BSP Tapered Male – BSPT to ISO 7 / BS 21. It seals on the tapered thread itself, so it needs PTFE tape or a liquid thread sealant.
• 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 end seals on the O-ring against the port spotface, not on the thread. If the port face is burred or the ring is missing it will weep no matter how tight it is.
• Do not force a UNO male into a BSPP port. Both are straight threads and they will start, but the pitch is wrong and it will strip.
• The BSPT end still wants thread sealant. The UNO end does not, and sealant on that thread does nothing but make a mess.

Technicians Advice

Run the O-ring down to the shoulder before you start the fitting, then wind it in until the ring just touches the spotface and give it the specified turn from there. Cranking a UNO fitting past that point extrudes the ring out the side and you get a leak that looks like a thread fault but is not.

Where You’ll Find It

• BSP Tapered Male – Older Australian and British pipework, gauge ports, tank and return lines, and cast pump and gearbox housings.
• 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

• BSP Tapered Male – BSPT to ISO 7 / BS 21, written R for male. Sometimes labelled PT or BSP taper.
• 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	L	H1	Material	Finish
BTM-UNM-0407	1/4" BSPT	7/16" UNO	30mm	16mm	Mild steel	Plated finish
BTM-UNM-0408	1/4" BSPT	1/2" UNO	30mm	19mm	Mild steel	Plated finish
BTM-UNM-0409	1/4" BSPT	9/16" UNO	31mm	19mm	Mild steel	Plated finish
BTM-UNM-0412	1/4" BSPT	3/4" UNO	33mm	22mm	Mild steel	Plated finish
BTM-UNM-0414	1/4" BSPT	7/8" UNO	37mm	27mm	Mild steel	Plated finish
BTM-UNM-0607	3/8" BSPT	7/16" UNO	30mm	19mm	Mild steel	Plated finish
BTM-UNM-0609	3/8" BSPT	9/16" UNO	31mm	19mm	Mild steel	Plated finish
BTM-UNM-0612	3/8" BSPT	3/4" UNO	33mm	22mm	Mild steel	Plated finish
BTM-UNM-0614	3/8" BSPT	7/8" UNO	37mm	27mm	Mild steel	Plated finish
BTM-UNM-0809	1/2" BSPT	9/16" UNO	37mm	22mm	Mild steel	Plated finish
BTM-UNM-0812	1/2" BSPT	3/4" UNO	38mm	22mm	Mild steel	Plated finish
BTM-UNM-0814	1/2" BSPT	7/8" UNO	43mm	27mm	Mild steel	Plated finish
BTM-UNM-0817	1/2" BSPT	1.1/16" UNO	46mm	32mm	Mild steel	Plated finish
BTM-UNM-0821	1/2" BSPT	1.5/16" UNO	46mm	38mm	Mild steel	Plated finish
BTM-UNM-1212	3/4" BSPT	3/4" UNO	42mm	30mm	Mild steel	Plated finish
BTM-UNM-1214	3/4" BSPT	7/8" UNO	44mm	32mm	Mild steel	Plated finish
BTM-UNM-1217	3/4" BSPT	1.1/16" UNO	46mm	32mm	Mild steel	Plated finish
BTM-UNM-1221	3/4" BSPT	1.5/16" UNO	47mm	38mm	Mild steel	Plated finish
BTM-UNM-1617	1" BSPT	1.1/16" UNO	51mm	36mm	Mild steel	Plated finish
BTM-UNM-1621	1" BSPT	1.5/16" UNO	51mm	38mm	Mild steel	Plated finish
BTM-UNM-1626	1" BSPT	1.5/8" UNO	58mm	50mm	Mild steel	Plated finish
BTM-UNM-2021	1.1/4" BSPT	1.5/16" UNO	57mm	50mm	Mild steel	Plated finish
BTM-UNM-2026	1.1/4" BSPT	1.5/8" UNO	57mm	50mm	Mild steel	Plated finish
BTM-UNM-2030	1.1/4" BSPT	1.7/8" UNO	59mm	55mm	Mild steel	Plated finish
BTM-UNM-2426	1.1/2" BSPT	1.5/8" UNO	56mm	50mm	Mild steel	Plated finish
BTM-UNM-2430	1.1/2" BSPT	1.7/8" UNO	59mm	55mm	Mild steel	Plated finish

Key: L overall length, H1 centre to face 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

🔗 45° Compact – same threads🔗 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.