DIN 2353 Fitting Sizes: Metric Bite-Type Thread Data
DIN 2353 / ISO 8434-1 Thread Sizes
| Tube OD | Thread |
|---|---|
| 6 mm | M12x1.5 |
| 8 mm | M14x1.5 |
| 10 mm | M16x1.5 |
| 12 mm | M18x1.5 |
| 15 mm | M22x1.5 |
| 18 mm | M26x1.5 |
| 22 mm | M30x2 |
| 28 mm | M36x2 |
| 35 mm | M45x2 |
| 42 mm | M52x2 |
DIN metric fittings are the European standard for hydraulic tube connections. They use a bite-type ring (cutting ring or olive) that bites into the tube to create a seal against a 24-degree cone. The metric threads and 24-degree seat angle distinguish them from JIC (37-degree). Common on European-made machinery, especially from Germany, Sweden, and Italy.
When to Use DIN 2353 / ISO 8434-1
European industrial hydraulics, machine tools, injection molding.
If the machine came from Europe and uses metric tubing, it probably uses DIN fittings.
Reliable up to very high pressures (800 bar / 11,600 psi in heavy series).
DIN 2353 / ISO 8434-1 Limitations
The cutting ring must be pre-set properly or it will not seal.
Not interchangeable with JIC despite both being flare-type connections (24-degree vs 37-degree).
Requires metric tube sizes, which can be hard to source in North America.
How to Identify DIN 2353 / ISO 8434-1 Fittings
Metric threads (measure in mm). 24-degree cone angle. Look for a separate cutting ring on the tube. Body hex sizes are metric.
DIN 2353 / ISO 8434-1 Measurement Tips
DIN fittings use a cutting ring (also called a ferrule or olive) that bites into the tube when the nut is tightened. The tube must be properly prepared: square cut, deburred, and the correct wall thickness for the fitting size. If the tube is not prepped correctly, the cutting ring will not seat properly and the fitting will leak under pressure. Always use a pre-assembly tool to set the cutting ring before final assembly.
What DIN 2353 / ISO 8434-1 Is Confused With
DIN 2353 and ISO 8434-1 describe the same fitting system. DIN 2353 is the original German standard, and ISO 8434-1 is the international adoption of it. The dimensions are identical. Some catalogs list both numbers for the same fitting. If your spec calls for ISO 8434-1, you can use DIN 2353 fittings and vice versa.
Data sourced from DIN 2353, ISO 8434-1. Thread dimensions are nominal values. Always verify with a thread identification gauge before making connections.