Thread identification
Flat-Face & Metric Face-Seal Variants
Several equipment builders use flat-face O-ring fittings with metric threads — visually identical to ORFS but thread-incompatible. If a 'flat face' fitting won't start smoothly on an ORFS part, stop and measure the pitch before forcing it.
Identify it
Four checks at the bench.
- 01
Confirm a flat sealing face with O-ring groove, as with ORFS
- 02
Measure thread OD in millimeters and pitch with a metric gauge
- 03
Compare against ORFS inch sizes — close-but-not-equal numbers mean metric
- 04
Identify the equipment origin: Japanese and European machines are prime metric-face candidates
Don't confuse it with…
- ORFS inch threads are the classic mix-up — threads gall and the joint fails at pressure
- Komatsu-style 30° flare with metric threads is a different metric family again
Reference
Size chart.
| Size | Thread |
|---|---|
| M14×1.5 | common on compact equipment |
| M16×1.5 | common |
| M18×1.5 | common |
| M22×1.5 | common |
| M26×1.5 | larger circuits |
| M33×2 | larger circuits |
A1 stocks it.
Unsure even after the checks? Bring the fitting to the counter — gauging an unknown thread takes us about a minute. (817) 589-7101.
Flat-Face & Metric Face-Seal Variants — FAQs
My new ORFS fitting won't thread on — why?
You likely have a metric flat-face fitting. Measure pitch in millimeters; if it's 1.5 mm rather than an inch pitch, it's metric and needs the metric part.
Can A1 match metric flat-face fittings?
Yes — bring the fitting or the machine's port info and we'll match it from stock or source it quickly.