Brass Bulkhead Union
When a tube run must continue straight through a cabinet wall, tank shell, or machine frame, a bulkhead union does the job in one piece: compression ends grip the tube on both faces of the panel while a locknut clamps the threaded body in the drilled hole. It uses the same ferrule system as all our brass compression fittings. Definite Metal turns brass bulkhead unions from CW614N in Jamnagar, India, covering 4 mm to 25 mm and 1/8″ to 1″ tube, built for bulk purchase by OEMs, distributors, and exporters’ programmes. Pair with a male connector where the line ends at a tapped port.
Dimensions & Specifications
| Tube OD, both ends (mm) | Nearest inch OD | Panel hole diameter (mm) | Max panel thickness (mm) | Locknut across flats (mm) | Overall length, nut to nut (mm) | Typical max working pressure (bar) |
|---|---|---|---|---|---|---|
| 4 | 5/32" | 10.5 | 4 | 14 | 40 | 25 |
| 6 | 1/4" | 12.5 | 5 | 17 | 44 | 25 |
| 8 | 5/16" | 14.5 | 5 | 19 | 48 | 25 |
| 10 | 3/8" | 17.0 | 6 | 22 | 52 | 20 |
| 12 | 1/2" | 20.5 | 6 | 26 | 58 | 16 |
| 15 | 5/8" | 24.0 | 8 | 30 | 64 | 16 |
| 22 | 7/8" | 32.0 | 8 | 38 | 76 | 16 |
| 25 | 1" | 36.0 | 10 | 43 | 84 | 16 |
Nut-to-nut lengths are nominal with tube fully inserted; reduced or extended bodies are produced to customer drawings.
Materials — Brass Grades
Union bodies, locknuts, compression nuts, and ferrules come from one material family for consistent plating and corrosion behaviour:
| Grade | Standard | Role |
|---|---|---|
| CW614N (CuZn39Pb3) | EN 12164 | Standard grade for the through-body and all nuts |
| CW617N (CuZn40Pb2) | EN 12165 | Forging route for heavy-wall large-bore unions |
| IS 319 | Indian Standard | Substitutable free-cutting grade on IS-specified contracts |
Also available in MS and SS 303/304/316 on request.
Finish Options
- Natural brass (self colour)
- Nickel plated
- Tin plated
- Chrome plated
Manufacturing & Export Capability
Custom manufacturing from drawing/sample · Tolerance ±0.01 mm · MOQ: 500 pcs · Lead time 1–2 weeks · ISO 9001:2015 · Export packing · FOB Mundra / CIF worldwide · Brass specialist in Jamnagar, India’s brass city
18+ years of manufacturing experience · 19 skilled workers · Sales@definitemetal.com
Applications & Industries
Bulkhead unions are fitted in refrigeration and chiller cabinets, marine fuel and freshwater systems, CNG kit installations, and skid-mounted process equipment where copper or nylon lines cross enclosure walls. Because the joint can be broken on either face, service engineers in HVAC and beverage-equipment maintenance favour them at every serviceable panel crossing.
Frequently Asked Questions
Pick the union when tube continues on both sides of the panel; pick the female bulkhead when the far side connects to a threaded component rather than another tube. Both mount through the same style of drilled hole with a locknut.
The standard union is equal-ended, but reducing versions — say 10 mm on one face and 8 mm on the other — are a straightforward custom job from drawing since each end is machined independently.
Email the size list, finish, and target quantities to Sales@definitemetal.com for a quotation; as a bulk manufacturer we agree minimums per line item rather than a blanket figure. All lots trace to ISO 9001:2015 process records, and composition or RoHS documents accompany shipments when asked.
Consignments leave Mundra port under FOB or CIF Incoterms, in carton-and-pallet export packing with each size bagged and labelled separately for easy warehouse receiving.