Fitting family
JIS 30° and Komatsu 30° flare fittings
Two Japanese cone-seat connections with a 30° seat: JIS uses BSP parallel threads, Komatsu uses metric fine threads.
What it is
Japanese equipment uses cone-seat fittings that look like JIC at a glance but have a 30° seat and different threads. JIS 30° fittings use the same parallel threads as BSPP. Komatsu 30° fittings use metric fine threads.
The 30° seat appears in two layouts depending on the fitting style: as a cone on the male nose, or as an inverted seat inside the male. In both cases the mating half carries the matching 30° surface.
- Thread
- JIS: BSP parallel (G). Komatsu: metric fine, 1.5 mm pitch
- Seal
- Metal-to-metal on a 30° seat
- Standard
- JIS B 8363 (JIS 30° flare); Komatsu factory standard
- Also called
- JIS flare, Japanese 30°, Komatsu style
What it looks like
How to recognise it
- A cone seat that measures 30° from the axis on a seat gauge, against 37° for JIC.
- JIS: the thread matches a BSP gauge, for example 19 TPI on 1/4 in and 3/8 in.
- Komatsu: the thread is metric with a 1.5 mm pitch, for example M18×1.5.
- The machine is Japanese or Korean in origin.
Where it is used
JIS 30° is found on Japanese and Korean machines such as Hitachi, Kobelco, Kubota, Doosan and Hyundai. The metric 30° style is specific to Komatsu. Newer machines from all of these brands also use O-ring face seal.
Size chart
| Size | Thread | Male thread OD (nominal) | Pitch |
|---|---|---|---|
| M14 | M14x1.5 | 14.00 mm / 0.551 in | 1.5 mm |
| M18 | M18x1.5 | 18.00 mm / 0.709 in | 1.5 mm |
| M22 | M22x1.5 | 22.00 mm / 0.866 in | 1.5 mm |
| M24 | M24x1.5 | 24.00 mm / 0.945 in | 1.5 mm |
| M30 | M30x1.5 | 30.00 mm / 1.181 in | 1.5 mm |
| M33 | M33x1.5 | 33.00 mm / 1.299 in | 1.5 mm |
| M36 | M36x1.5 | 36.00 mm / 1.417 in | 1.5 mm |
| M42 | M42x1.5 | 42.00 mm / 1.654 in | 1.5 mm |
Seal: 30° cone seat, metal to metal. Metric fine thread with a 30° flare seat. Found mainly on Komatsu machines; check the seat angle before matching to DIN.
| Size | Thread | Male thread OD (nominal) | Pitch |
|---|---|---|---|
| 1/8 in | G 1/8 | 9.73 mm / 0.383 in | 28 TPI |
| 1/4 in | G 1/4 | 13.16 mm / 0.518 in | 19 TPI |
| 3/8 in | G 3/8 | 16.66 mm / 0.656 in | 19 TPI |
| 1/2 in | G 1/2 | 20.96 mm / 0.825 in | 14 TPI |
| 5/8 in | G 5/8 | 22.91 mm / 0.902 in | 14 TPI |
| 3/4 in | G 3/4 | 26.44 mm / 1.041 in | 14 TPI |
| 1 in | G 1 | 33.25 mm / 1.309 in | 11 TPI |
| 1-1/4 in | G 1-1/4 | 41.91 mm / 1.650 in | 11 TPI |
| 1-1/2 in | G 1-1/2 | 47.80 mm / 1.882 in | 11 TPI |
| 2 in | G 2 | 59.61 mm / 2.347 in | 11 TPI |
JIS 30° flare uses these G threads with a 30° seat instead of a 60° cone.
Commonly confused with
- JIC 37°
- Similar appearance. JIC has UN threads and a 37° seat.
- BSPP 60° cone
- Same G thread as JIS. BSPP has a 60° cone.
- Metric DIN 24°
- Same metric threads as Komatsu. DIN has a 24° cone and a tube counterbore.
Interchangeability
JIS 30°, Komatsu 30°, BSPP 60° and JIC 37° do not interchange with one another, even where the threads match. Mixing them gives a line contact that leaks under pressure.
Frequently asked questions
What fittings does Komatsu use?
Older and many current Komatsu machines use Komatsu 30° flare fittings with metric fine threads such as M18×1.5 and M22×1.5. Newer models also use O-ring face seal. Always measure the fitting on the machine.
Is JIS the same as BSP?
JIS 30° flare fittings use the same parallel pipe thread as BSPP, but the seat is 30° rather than the 60° cone of a BSPP hose fitting, so they do not seal against each other.
How do I tell JIS from JIC?
Check the thread first: JIC is UN, JIS is BSP. Then check the seat angle with a gauge: JIC is 37°, JIS is 30°.
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Dimensions are nominal reference values. Confirm against the standard or the fitting manufacturer before ordering.