ORFS Thread Size Chart

What it is

ORFS (O-ring face seal) fittings, covered by SAE J1453 and ISO 8434-3, seal with an O-ring held in a groove on the flat face of the male fitting. The female swivel has a flat, smooth face that presses on the O-ring. Threads are UN straight threads. The dash number is the tube OD in sixteenths of an inch. ORFS is used where leak resistance and vibration resistance matter.

How to identify

• The male has a flat face with an O-ring in a groove. There is no cone or flare.
• The female has a flat face inside the swivel nut.
• Measure the male thread OD and pitch. ORFS threads are larger than JIC for the same dash size.

Thread size chart

Key points

• ORFS -4 and JIC -6 share 9/16-18. An ORFS -4 nut will thread onto a JIC -6 male, but it will not seal. Check for the flat face.
• The O-ring is a specific size for each dash number. Use the fitting maker's replacement O-ring, usually the same compound as original.
• Replace the face O-ring whenever the joint is taken apart.
• Lightly lubricate the O-ring with system fluid before assembly. Make sure it is seated in the groove.
• Tighten to the fitting maker's torque. Do not use thread sealant.

Common mistakes

• Reusing a flattened or nicked face O-ring.
• Losing the O-ring during assembly and not noticing.
• Ordering by dash number without confirming ORFS versus JIC.

Governing standards: SAE J1453 (O-ring face seal fittings); ISO 8434-3 (international equivalent); fitting manufacturer assembly and O-ring data.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.