Views: 0 Author: Lynn Liu Publish Time: 2026-09-22 Origin: Site
The 1EN is a straight hydraulic adapter that joins two different thread worlds. One end is a metric male with an O-ring. The other end is a male NPT tapered pipe thread. It is the standard part for connecting a metric ported block or cylinder to a hose or pipe laid out with NPT ends. This guide covers the thread pairs, pressure ratings, sealing rules and common uses for the 1EN series.
The 1EN is a forged straight adapter. The metric end uses a parallel thread with a soft O-ring seated in a groove on the boss. The O-ring compresses against a flat or recessed port face and carries the seal. The NPT end is a tapered male pipe thread. It seals through thread interference and needs thread sealant.
Ruihua hardware machines the 1EN from C45 carbon steel and ships every piece with a thread protect cap. Each adapter is pressure-tested before packing. The series is dimensionally matched to common North American catalog patterns, so it can replace worn or missing adapters on imported machines.
Forged C45 / AISI 1045 carbon steel body for high burst strength.
Color zinc or white zinc plating — passes 96 h neutral salt spray (ASTM B117).
Precision-machined metric parallel thread with captive O-ring groove on the metric end.
Tapered NPT male thread machined to ANSI/ASME B1.20.1.
Thread protect caps on both threads — no packing damage in transit.
100% pressure testing before delivery.
Item |
Specification |
|---|---|
Series code |
1EN |
Configuration |
Straight adapter, male / male |
Metric end |
Metric male parallel thread with O-ring boss, M14x1.5 to M42x2 |
NPT end |
NPT male tapered pipe thread, 1/8 to 1-1/4 inch |
Material |
C45 / AISI 1045 carbon steel |
Surface treatment |
Color zinc or white zinc, trivalent passivation |
Working pressure |
Up to 5000 PSI by size (see pressure table below) |
Temperature range |
-40 °C to +120 °C with standard NBR O-ring |
Sealing |
O-ring on metric end; sealant on NPT end |
Packing |
Thread protect cap + plastic bag + carton + pallet |
Reducing combinations, such as M22x1.5 to 3/4" NPT, can be produced on request. Confirm the metric pitch and the O-ring groove size before ordering a replacement.
Connect metric-port valve manifolds and cylinders to NPT pipe or hose runs on imported equipment.
Bridge metric OEM blocks and North American NPT plumbing in retrofit and rebuild projects.
Pump and power pack assemblies that mix metric and imperial ports.
Field repairs on construction and agricultural machinery where the original metric adapter is unavailable.
Industrial presses and injection machines with mixed-thread hydraulic circuits.
Check the O-ring before assembly. Replace it if it is cut, flat or swollen.
Oil the O-ring lightly. Slide the adapter straight into the metric port. Never cross-thread a parallel thread.
Torque the metric nut or body to the port maker's specification. Over-torque does not improve the seal. It only damages the O-ring.
Wrap PTFE tape on the NPT end in the direction of thread rotation, or use a rated pipe dope. Keep sealant off the first two threads.
Pressure-test the joint at working pressure before the line goes into service.
Ruihua hardware is a hydraulic fitting factory in Yuyao, Zhejiang, with more than a decade of export experience. The 1EN series is made on CNC machining lines with full in-process inspection. Every adapter passes a pressure test before it leaves the plant. Standard parts ship in 7 to 15 days. Custom thread pairs, stainless steel versions and OEM laser marking are welcome. You can browse the full product catalog or send a drawing for a same-week quotation.
A metric male O-ring adapter uses a parallel metric thread with a soft O-ring on the boss face. It seals against a flat or recessed port face. A metric 24-degree cone adapter has no O-ring. It seals metal to metal on a 24-degree internal cone. The two systems are not interchangeable without changing the port. See our metric fitting identification guide for measurement steps.
Standard pairs run from M14x1.5 with 1/8" NPT up to M42x2 with 1-1/4" NPT. Intermediate sizes include M16x2 with 1/4" NPT, M22x1.5 with 1/2" NPT, M27x2 with 3/4" NPT and M33x2 with 1" NPT. Mixed or reducing combinations can be made to order.
Yes. The NPT male thread is tapered and seals through thread interference. Apply PTFE tape or a rated pipe dope on the NPT side only. Keep sealant off the first two threads so it cannot enter the system. The metric O-ring end needs no sealant.
It depends on the size. Small sizes such as M14x1.5 with 1/8" NPT are rated near 5000 PSI. Mid sizes such as M22x1.5 with 1/2" NPT are rated near 4000 PSI. Large sizes above 1" NPT are rated around 2500 to 3000 PSI. Every adapter is pressure-tested before shipment.
Yes. Ruihua hardware supplies the 1EN in carbon steel with color or white zinc plating as standard. Stainless steel 316, special thread pairs, custom lengths, laser marking and OEM packaging are available on request.
1EZ metric male O-ring / BSP male straight — the same metric O-ring end paired with a BSP male thread.
BE metric male O-ring / metric female tee — metric O-ring tee for branching metric port lines.
6E metric male O-ring bulkhead — metric O-ring bulkhead adapter for panel pass-through.
Hydraulic fitting types explained — how JIC, ORFS, NPT, BSP and metric systems seal and where each one fits.
Send us your thread sizes and quantity. We reply with a quote within one working day. Standard 1EN adapters ship in 7 to 15 days. Custom thread pairs and stainless steel versions are available. Contact Ruihua hardware to start your inquiry.
