Thread identification
JIS 30° Cone (JIS B8363)
JIS hydraulic fittings pair a 30° inverted cone seat with BSPP or metric threads and are standard on Japanese equipment — Komatsu-pattern metric and BSP-thread variants both appear in US fleets.
Identify it
Four checks at the bench.
- 01
Female nose shows a 30° cone (shallower than JIC's 37°)
- 02
Thread is BSPP (19/14 TPI Whitworth) or metric fine
- 03
Common on Japanese excavators, cranes, and trucks
- 04
Check machine origin plus thread gauge before assuming BSP or metric
Don't confuse it with…
- BSPP 60° cone shares the thread but not the seat angle — they cross-thread happily and seal never
- JIC 37° on inch threads is a different animal entirely; don't force Japanese lines onto US cones
Reference
Size chart.
| Size | Thread |
|---|---|
| G1/4 × 30° cone | common |
| G3/8 × 30° cone | common |
| G1/2 × 30° cone | common |
| M14×1.5 Komatsu | common |
| M16×1.5 Komatsu | common |
| M18×1.5 Komatsu | common |
A1 stocks it.
Unsure even after the checks? Bring the fitting to the counter — gauging an unknown thread takes us about a minute. (817) 589-7101.
JIS 30° Cone (JIS B8363) — FAQs
Why won't a BSP fitting seal on my Komatsu line?
Komatsu-pattern ends are often metric-thread 30° cone, not BSP. Same look, different thread — measure the pitch in millimeters.
Can A1 build JIS-ended hoses?
Yes, both BSP-thread and metric Komatsu-pattern 30° cone ends are part of our import-equipment stock.