Account
Inquiry
Getting fittings that actually seal on the first tighten without crushing the tube is pretty much whole battle, and these double ferrule unions get it right. We’ve been using them across three different hydraulic lines and a gas test bench, and what it does is it grips the tubing with that front ferrule while the back one pushes it forward — no leaks even at 4000 PSI or so, usually we run them right up to the 6000 PSI rating but stay a touch under for safety. The stainles 316 versions hold up better in corrosive environments than the 304 if you’re pushing them near the top of the tempearture range, which is rated form -20°C to 200°C.
Thread standard vary wildly depending on what you’re connecting to, so having Metric, NPT, BSPP, BSPT, JIS, and SAE on the same union is actually handy. Most buyers in our shop go with NPT because that’s what our accumulators and valves use, but we’ve also ordered BSPP unions for a European water system — they’re all machined with the same tolerance, so mixing thread types on a job isn’t a headache. we found is that the satin finish doesn’t wipe down as clean as polished if you’ve got oil residue, but it doesn’t affect the seal.
And the double ferrule design means you don’t need thread sealant or tape on the union itself — just torque it to spec and it holds. We had one batch on high-vibration compressor line for about six months, and none of them backed off even a quarter turn, which is better than some cheaper threaded connectors we tested. Teh RoHS compliance is a bonus for any system that touches potable water, though these aren’t really suited for steam service above 180°C (check the lead time for 316L if that’s what you need).
For customization, we’ve ordered a batch with polished finish and a specific hex size (not standard across all sizes) for a tight manifold — the supplier usually has stock on standard 2-3 week lead times, but for custom ferrule lengths or mixed thread types, it can stretch to 4 weeks. 2 out of 3 orders we place are standard union connectors, so we keep a pallet of 1/4 inch NPT stainless unions on hand because most buyers go with that size. The MOQ for custom runs is typically 50 units or so, with the COA coming with every batch.
Basically, if you’re tired of chasing leaks on adapters or swapping fittings between systems, these are what you keep in the bin. We ship them in poly bags with individual labels, and the carbon steel versions (which are cheaper and fine for dry gas lines) come with a light oil coating to prevent rust during storage. The packaging is standard — heavy-duty carton with foam inserts for larger quantities, but smaller orders just get bubble-wrapped and boxed.
For standard sizes in 304/316, the MOQ is 50 pieces per size. If you need carbon steel or less common thread standards, the MOQ might go up to 100 pieces.
Yes, we can include mill test reports for the stainless steel and a certificate of conformance with the order. Just let us know when you place the order, and we'll add them at no extra cost.
Absolutely, we can do polished finish with NPT threads. The satin finish is standard, but polished is available on request—just keep in mind it might add a few days to the lead time.
The 1/4-inch 316 stainless version is rated up to 6000 PSI, same as the rest of the line. That holds for all connection types—male, female, or union—as long as the tube wall thickness matches the spec.
Yes, they work fine for water lines, with the temperature range from -20°C to 200°C. For packaging, we can do bulk boxes or individual polybags—just specify your preference when ordering.
