How to measure an RJT Coupler?
How to Measure RJT Ferrules (Step-by-Step)
1. Measure the Outside Diameter (OD)
The most important measurement is the outside diameter (OD) of the ferrule or pipe.
-Use a vernier caliper for best accuracy
-Measure across the widest part of the ferrule face
👉 This measurement is what determines your RJT size.
2. Avoid Measuring Threads
RJT threads can be misleading due to their rounded profile.
❌ Don’t rely on:
-Thread diameter
-Thread pitch
✅ Always prioritise:
-Ferrule OD
-Pipe OD
3. Inspect the Sealing Face
RJT fittings seal using a cone + gasket system, so condition matters.
Check for:
-Scratches
-Dents
-Wear on the sealing face
Even the correct size won’t seal properly if the ferrule is damaged.
RJT Ferrule Size Chart
Use the table below to match your measurement:
| Nominal Size | Outside Diameter (OD) |
|---|---|
| 1" | ~25 mm |
| 1.5" | ~38 mm |
| 2" | ~51 mm |
| 2.5" | ~63.5 mm |
| 3" | ~76 mm |
| 4" | ~102 mm |
👉 Tip: Measurements may vary slightly depending on manufacturing tolerances.
Common Mistakes to Avoid
❌ Confusing RJT with Tri-Clamp or DIN fittings
❌ Measuring threads instead of ferrule OD
❌ Ignoring worn sealing faces
❌ Guessing size without measuring
Need Help Identifying Your RJT Ferrule?
At Milky Fittings, we help customers identify the correct fittings every day.
-If you're unsure:
-Send us a photo
-Include a quick measurement
-We’ll confirm the correct size for you
-See video in the link below https://www.youtube.com/watch?v=r47acIbFF-M&ab_channel=TheMetalCompany