Thread & Size Identification Guide
Identify the thread of your fitting in a few steps and find the right product fast.
By: MCF Flex · Updated: 21.06.2026
Quick comparison
Thread Standards
| Standard | Angle | Form | Sealing | Use |
|---|---|---|---|---|
| BSP (BSPP / BSPT) | 55° | Parallel (G) / Taper (R) | O-ring/bonded (parallel) · thread (taper) | European hydraulics, most common |
| Metrik (DIN 2353) | 60° | Parallel | 24° cone or O-ring | Metric tube connections |
| UNF / JIC 37° | 60° | Parallel | 37° flare | US/JIC systems |
| ORFS | 60° | Parallel (UN) | O-ring on flat face | High vibration/pressure |
| NPT / NPTF | 60° | Taper | Taper thread + tape | US pipe thread |
| Komatsu | 30° | Metric cone | 30° flare | Construction (Komatsu) |
In 4 steps
How to Identify Your Thread
01
Parallel or taper?
Look from the side. Same diameter throughout = parallel; narrowing toward the tip = taper (NPT, BSPT).
02
Measure the diameter
With a caliper, measure the male thread outside diameter (O.D.) or female inside diameter in mm.
03
Determine the pitch
Use a thread gauge: threads per inch (TPI) for imperial, thread spacing (mm) for metric.
04
Check the seat angle
Seat angle: 37° (JIC), 24° (DIN), 30° (Komatsu), flat face + O-ring (ORFS).
BSP — Male Thread O.D.
| Size | O.D. | TPI |
|---|---|---|
| 1/8" | 9,7 mm | 28 |
| 1/4" | 13,2 mm | 19 |
| 3/8" | 16,7 mm | 19 |
| 1/2" | 21,0 mm | 14 |
| 3/4" | 26,4 mm | 14 |
| 1" | 33,2 mm | 11 |
| 1.1/4" | 41,9 mm | 11 |
| 1.1/2" | 47,8 mm | 11 |
| 2" | 59,6 mm | 11 |
Metric — Common Hydraulic Threads
| Thread | Dia. | Pitch |
|---|---|---|
| M12 × 1,5 | 12 mm | 1,5 |
| M14 × 1,5 | 14 mm | 1,5 |
| M16 × 1,5 | 16 mm | 1,5 |
| M18 × 1,5 | 18 mm | 1,5 |
| M22 × 1,5 | 22 mm | 1,5 |
| M27 × 2 | 27 mm | 2,0 |
| M30 × 2 | 30 mm | 2,0 |
| M33 × 2 | 33 mm | 2,0 |
| M42 × 2 | 42 mm | 2,0 |
Values are approximate references; nominal size differs from actual thread diameter (e.g. 1/2" BSP ≈ 21 mm O.D.).
Still not sure?
Match step by step with the Product Finder, or contact us with a sample/photo.