DIN vs JIS Fittings: European Metric vs Japanese Metric Compared

The key difference: DIN uses a 24-degree cone with a cutting ring (bite-type) that grips the tube OD. Full breakdown below.

DIN 2353 uses metric threads with a 24-degree cone and cutting ring for tube connections. JIS B 2351 uses metric threads with a 30-degree flare. Both use metric sizing, but the seal geometry, cone angles, and assembly methods are different.

Key Differences

DIN uses a 24-degree cone with a cutting ring (bite-type) that grips the tube OD.

JIS uses a 30-degree flare cone without a cutting ring.

DIN requires tube preparation and correct cutting ring pre-assembly.

JIS requires flared tube ends.

Both use metric thread pitches but the thread specifications may differ for the same nominal size.

DIN is the European industrial standard.

JIS is the Japanese standard.

DIN fittings are heavier-duty for high-pressure industrial systems.

JIS fittings are lighter and optimized for mobile equipment.

Practical Notes

DIN and JIS both use metric threads but are not interchangeable. The cone angles (24 vs 30 degrees) and assembly methods (cutting ring vs flare) are fundamentally different. The most common scenario where both appear is a Japanese machine in a European factory, or European attachments on Japanese base machines. Adapters are available from hydraulic suppliers that serve international equipment fleets.

Common Mistake

Assuming all metric hydraulic fittings are the same standard. DIN and JIS both use metric threads but the seal geometry is completely different. Thread pitch alone does not identify the standard. You must also check the cone angle and whether a cutting ring is present.