Hex Socket Plug for Hydraulic & Pneumatic Systems

Precision-Machined for Leak-Free Sealing and Reliable Installation

Designed for hydraulic and pneumatic applications, our hex socket plugs are manufactured entirely on Japanese high-speed precision drilling machines, delivering ±0.02 mm tolerance, stable sealing performance, and consistent installation quality in industrial systems.


  • High-Precision Machining:
  • Fully machined using Japanese high-speed precision drilling equipment, ensuring consistent hole geometry with tolerance controlled within ±0.02 mm.

  • No EDM Drilling Defects:
  • Eliminates irregular hole shapes and excessive deviation commonly caused by EDM drilling, improving sealing reliability and repeatability.

  • Clean & Magnet-Free Assembly:
  • All parts undergo ultrasonic cleaning and demagnetization to prevent contamination in hydraulic and pneumatic circuits.

  • 100% Gauge Pin Inspection:
  • Each plug is fully inspected with gauge pins to ensure dimensional accuracy and installation reliability.

Hex Socket Plug for Hydraulic & Pneumatic Systems

Internal Hex Screw Plug with ED Seal

Designed for hydraulic and pneumatic port sealing, the internal hex screw plug with ED elastic seal ensures reliable leak-free performance under high-pressure operating conditions.
Precision machining on high-speed Japanese drilling equipment guarantees consistent geometry and tolerance control within ±0.02 mm.


  • High-Precision Machining: Entirely processed using precision drilling machines, eliminating irregular hole geometry commonly caused by EDM processing.

  • ED Elastic Seal Design: Provides stable surface sealing according to DIN 3852 and ISO 9974-4 standards.

  • Ultrasonic Cleaning & Demagnetization: Ensures contamination-free installation in hydraulic and pneumatic circuits.

  • 100% Gauge Pin Inspection: Each part is individually inspected to guarantee dimensional accuracy and installation reliability.

  • Comprehensive Validation:Supported by 1,000,000 cycle pulse testing, burst pressure testing, over-torque testing, salt spray testing, and material spectral analysis reports.

Install using the recommended tightening torque to ensure optimal sealing performance.
Avoid excessive over-torque beyond specified limits to maintain thread and socket integrity.
hex socket plug for hydraulic & pneumatic systems
Technical Specifications
PART NO.THREADCAPTIVEl [mm]L [mm]D [mm]S [mm]Kg/100BAR
4BN-02WDG1/8″×28ED-108121450.7400
4BN-04WDG1/4″×19ED-1412171961.9
4BN-06WDG3/8″×19ED-1712172282.8
4BN-08WDG1/2″×14ED-21141927104.9
4BN-12WDG3/4″×14ED-27162132128.3315
4BN-16WDG1″×11ED-331622.5401713.4
4BN-20WDG1.1/4″×11ED-421622.5502220.5250
4BN-24WDG1.1/2″×11ED-481622.5552427.2
4MN-08WDM8×1ED-88121240.5400
4MN-10WDM10×1ED-108121450.7
4MN-12WDM12×1.5ED-1212171761.4
4MN-14WDM14×1.5ED-1412171961.9
4MN-16WDM16×1.5ED-1612172282.7
4MN-18WDM18×1.5ED-1812172483.2
4MN-20WDM20×1.5ED-20141926104.5
4MN-22WDM22×1.5ED-22141927105.3
4MN-26WDM26×1.5ED-27162132127.9315
4MN-27WDM27×2ED-27162132128.2
4MN-33WDM33×2ED-331622.5401713.3
4MN-42WDM42×2ED-421622.5502220.5250
4MN-48WDM48×2ED-481622.5552427.1

Quality & Supply Assurance FAQ

1. How do you ensure consistent sealing performance?

All screw plugs are manufactured under ±0.02 mm tolerance control using high-speed precision drilling machines.
Each batch undergoes ultrasonic cleaning, demagnetization, and full inspection with calibrated gauge pins to guarantee dimensional consistency and reliable ED elastic sealing performance.

2. What testing reports are available?

Products are validated by million-cycle pulse testing, burst pressure testing, over-torque testing, and salt spray corrosion testing. Material composition is verified through spectrographic analysis.
Relevant test reports are available upon request.

3. Do you comply with international standards?

The internal hex screw plugs comply with DIN 3852 and ISO 9974-4 standards.
Multiple metric thread sizes are available to ensure interchangeability with global hydraulic systems.

4. Can you support long-term and stable supply?

Yes. As a standardized high-volume component, this product is maintained under stable production scheduling and controlled raw material sourcing. Long-term supply agreements and safety stock arrangements can be supported.

5. How do you control batch-to-batch consistency?

Each production batch is traceable by material lot and machining record.
Key dimensions and sealing surfaces are fully inspected to minimize deviation risks and ensure repeatable performance across deliveries.

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