O-ring 3.4x0.9 NBR

Applications & Typical Use Cases

This O-ring 3.4x0.9 NBR 70 ShA is designed for general industrial sealing where oil resistance, medium temperature, and reliability are required. It is often used in bearing housings, bearing units, hydraulic/pneumatic valves, small pumps, fuel systems, gearboxes, and in assemblies involving ball bearings as a sealing interface. In many industrial and maintenance operations, such O-rings serve as cost-effective seals for static or low-movement joints, protecting components from oil leaks, dust ingress, and contamination.

Advantages & Technical Benefits

• Good oil / fuel resistance: The nitrile (NBR) composition offers robust compatibility with petroleum-based oils, greases, and many common industrial fluids, making it a preferred choice in industrial applications.

• Balanced hardness: At 70 ShA, the elastomer delivers solid sealing pressure without being too rigid, combining flexibility with durability.

• Compact cross-section: With a cross-section of just 0.9 mm and inner diameter 3.4 mm, it fits into tighter groove designs typical for compact assemblies in machinery.

• Bulk packaging for B2B use: Shipping in packs of 100 ensures efficient stock management, lower per-unit cost, and readiness for maintenance workflows.

• Dimensional consistency: Manufactured to tight tolerances, ensuring repeatable sealing performance in series parts or modular units.

• Wide availability & cost-effectiveness: NBR 70 ShA O-rings are a standard product range in the sealing industry, making them easy to source and integrate into supply chains.

Technical Specifications

Installation Tips & Use Guidelines

• In groove design, allow a light interference squeeze (typically 5-15 %) so that the O-ring contacts the sealing surfaces without excessive compression or extrusion risk.

• Use lubricants compatible with NBR (e.g. silicone or suitable grease) to ease installation, reduce friction, and minimize wear.

• Avoid exposure to aggressive chemicals, ozone, UV light, or high concentrations of solvents, which can degrade NBR over time.

• In assemblies with ball bearings or bearing units, ensure the O-ring is isolated from direct contact with shaft edges or sharp transitions to prevent cut or extrusion.

• Store rings in cool, dark, dry conditions, away from ozone sources or UV radiation, to maintain elasticity.

FAQ (Frequently Asked Questions)

Q1. Is this O-ring suitable for automotive fuel systems?
NBR offers good compatibility with many fuels and oils, but some modern fuels (ethanol blends, strong solvents) may reduce longevity. Always verify with the specific fluid.

Q2. How long will this O-ring last in service?
Under moderate temperature (<100 °C), clean oil media, and low dynamic stress, it can last for many years. In harsher environments, periodic inspection or replacement is recommended.

Q3. Can this O-ring be used in dynamic (moving) seals?
It can be used for light dynamic movements (reciprocating, slight oscillation), but in high-speed rotation or high friction jobs other elastomers (e.g. FKM) may perform better.

Q4. What does “70 ShA” mean for sealing performance?
It defines the hardness of the rubber: 70 Shore A is a balanced medium-firm hardness that gives a good trade-off between seal tightness and flexibility.

Q5. Why buy in packs of 100?
Bulk packs reduce per-unit cost, ensure stock for maintenance, and simplify ordering workflows in B2B and industrial settings.