BSP Tapered Male x SAE O-Ring Boss Male 45° Compact Elbow

BSPT into an Australian or British port, SAE O-ring boss male into an American pump or valve – the crossover you hit whenever US-built hydraulics land on local plumbing. The compact 45° body pulls the hose clear of the casting without the reach of a full 90.

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

• 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

• Check the boss, not the hose. SAE ORB ports have a machined spotface and a lead-in chamfer for the O-ring; a plain tapped hole is not an ORB port.
• BSPT and NPT look alike at a glance. BSPT is a 55° thread form, NPT is 60°, and mixing them gives a joint that starts easily and weeps forever.
• Take the O-ring size from the port. ORB O-rings are consumable and are often missing or flattened on a fitting that has been out before.

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.

Technicians Advice

Wind the ORB end in until the O-ring just touches the spotface, then tighten by feel only. Overtightening extrudes the O-ring into the thread and it will seep within a shift. The BSPT end is the opposite: it needs tape or sealant and real torque, because it seals on thread interference rather than a soft seal.

📐Dimensions & thread sizes – every size in this range

← Swipe the table sideways to see every measurement →

Part code	A	B	H	S1	Material	Finish
BTM-UNM-45C-0409	1/4" BSPT	9/16" UNO	17.5mm	14mm	Mild steel	Plated finish
BTM-UNM-45C-0812	1/2" BSPT	3/4" UNO	22.2mm	22mm	Mild steel	Plated finish
BTM-UNM-45C-1217	3/4" BSPT	1.1/16" UNO	31.8mm	27mm	Mild steel	Plated finish

Key: H centre to face, 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🔗 90° Compact – same threads

Express shipping Australia-wide. We dispatch daily to New South Wales, Victoria, Queensland, Western Australia, South Australia, Tasmania, the Australian Capital Territory and the Northern Territory – Sydney, Melbourne, Brisbane, Perth, Adelaide, Hobart, Canberra and Darwin, plus regional and remote sites.

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