Part block
Custom fittings, adapters, couplings and flanges
Fittings and couplings are judged by one thing: whether they seal. That makes the thread, the O-ring groove and the sealing face the three features that matter, and the rest of the part decoration.
What we make in this block
| Thread range | M5 – M64 metric; 1/8 in – 2 in BSP and NPT |
|---|---|
| Body sizes | Ø6 mm – Ø200 mm round; hex across flats 10 – 90 mm |
| O-ring groove tolerance | Groove width ±0.05 mm, depth ±0.02 mm, surface Ra 1.6 µm |
| Sealing face | Flatness 0.02 mm, Ra 0.8 µm |
| Pressure class | Quoted per drawing; parts machined to the wall thickness specified |
| Materials | Stainless 303 / 316 / 316L, brass H62, copper C110, aluminium 6061, titanium Gr2, POM, PTFE, PEEK |
| Finishes | Passivation, nickel plating, electropolishing, bead blasting, PTFE coating |
Thread type by material — common supply pairs
| Thread | Stainless 316 | Brass | Aluminium | POM / PTFE |
|---|---|---|---|---|
| M5 – M12 metric | Yes | Yes | Yes | Yes |
| 1/8 – 1/2 NPT | Yes | Yes | Yes | Yes |
| 1/8 – 1/2 BSP | Yes | Yes | Yes | Yes |
| M16 – M64 metric | Yes | Yes | Yes | Case by case |
| 1 in – 2 in NPT | Yes | Yes | Case by case | — |
Processes, materials and finishes
Processes
- CNC turning
- CNC milling (hex, ports)
- Thread milling
- Grooving
- Drilling and cross-porting
- Deburring
- Pressure testing (customer-specified)
Materials
- Stainless 303 / 316 / 316L
- Brass H62
- Copper C110
- Aluminium 6061
- Titanium Gr2
- POM
- PTFE
- PEEK
Finishes
- Passivation
- Electropolishing
- Nickel plating
- Bead blasting
- PTFE coating
- Pickling
How it is quoted
| Minimum order | 100 pieces per part number (prototype quantities from 1) |
|---|---|
| Sample lead time | 7–10 days after drawing approval |
| Production lead time | 25–35 days after sample approval |
| Quote turnaround | Within 24 hours, with DFM feedback |
Specific part pages in this block
- Fittings and adapters
- Flanges and couplings
- Hydraulic manifolds
- Bushings and sleeves
- Threaded inserts
Technical reading for this block
- CNC turning design rules
- Thread tap drill chart
- Fits and tolerances (H7/h6)
- Surface finish Ra chart
- Electropolishing
Questions
Can you machine NPT and BSP threads?
Yes, both, plus metric fine. The thread callout on the drawing must name the standard and the size — NPT and BSP are not interchangeable, and a bare 1/2 in leaves the choice to assumption.
How is an O-ring groove toleranced?
Groove width ±0.05 mm, depth ±0.02 mm, and Ra 1.6 µm on the groove surfaces. The depth is what sets the squeeze, so it is the tolerance that actually decides whether the part seals.
Do you pressure test fittings?
We machine to the drawing and can pressure test if the drawing specifies a test pressure and a method. The test is a separate line on the quote, and we report the result with the shipment.
Why does stainless gall when it is assembled?
Stainless-on-stainless threads cold-weld under load. The practical fixes are a molybdenum-free anti-seize, a different material pair (stainless into brass), or passivation plus a dry-film coating.
Send the drawing for fittings and couplings
Quotes come back within 24 hours with DFM feedback. Minimum order 100 pieces per part number; samples from one piece.