O-ring NBR 34x3.5 mm 70 Shore A

Characteristics of the NBR 70 Shore A O-ring 34x3.5 mm

The NBR 34x3.5 mm O-ring is a circular elastomeric sealing element designed to prevent or reduce fluid and gas leakage between mating components.

Its round cross-section allows the material to deform under controlled compression, creating contact pressure against the sealing surfaces.

NBR is widely used in industrial sealing applications because of its compatibility with many mineral oil-based lubricants and greases.

The nominal hardness of 70 Shore A provides a commonly used balance between elastic deformation and resistance to mechanical loading.

Key product characteristics:

• Inner diameter: 34 mm - nominal internal diameter of the sealing ring.

• Cross-sectional diameter: 3.5 mm - nominal thickness of the circular elastomer profile.

• Nominal outer diameter: 41 mm - calculated from the inner diameter and cross-section.

• Material: NBR - nitrile butadiene rubber.

• Hardness: 70 Shore A - nominal elastomer hardness.

• Construction: Continuous circular ring with a round cross-section.

• Sealing function: Suitable for properly designed static sealing arrangements and selected dynamic applications.

• Packaging: 100 pieces per pack for industrial supply, maintenance, and repair operations.

Technical Specifications

The nominal outer diameter of 41 mm is calculated from the inner diameter and twice the cross-sectional diameter.

Actual dimensions are subject to manufacturing tolerances. A specific dimensional tolerance class has not been established for this product.

What Does NBR 70 Shore A 34x3.5 mm Mean?

NBR

NBR stands for nitrile butadiene rubber, a synthetic elastomer commonly used in seals exposed to compatible mineral oils, lubricating greases, and selected industrial fluids.

Its chemical resistance depends on the specific rubber compound, operating temperature, fluid composition, and duration of exposure.

70 Shore A

This designation specifies the nominal hardness of the elastomer on the Shore A scale.

Hardness influences the sealing ring's deformation, contact pressure, installation behavior, and resistance to extrusion under pressure.

34 mm

The nominal inner diameter of the O-ring measured in its free, uninstalled condition.

3.5 mm

The nominal diameter of the circular cross-section.

100 pieces

The number of individual O-rings supplied in one commercial package.

Construction and Operating Principle

The NBR 34x3.5 mm O-ring consists of a continuous elastomeric ring with a circular cross-section.

When installed in a correctly dimensioned groove, the O-ring is compressed between the mating surfaces.

This compression creates initial sealing contact pressure, helping prevent fluid or gas from passing through the connection.

When system pressure is applied, the O-ring may deform further toward the low-pressure side of the groove, increasing contact with the sealing surfaces.

Effective sealing depends on several factors, including groove dimensions, compression ratio, groove fill, extrusion gap, surface finish, operating pressure, temperature, and fluid compatibility.

The 70 Shore A hardness is commonly selected for general-purpose industrial sealing applications, but suitability must always be assessed against the requirements of the specific installation.

Chemical Compatibility of NBR

Nitrile butadiene rubber is commonly used in industrial sealing systems, particularly where mineral oil-based lubricants are present.

These characteristics describe the NBR elastomer family and do not represent laboratory test results for the specific rubber compound used in this product.

Compatibility with a particular fluid should be verified before installation.

NBR 70 Shore A Compared with Other O-ring Materials

O-rings with identical nominal dimensions but different elastomer materials or hardness values are not automatically interchangeable.

Material selection must account for fluid compatibility, temperature, pressure, installation geometry, and service conditions.

Selection and Interchangeability of the 34x3.5 mm O-ring

Before selecting a replacement O-ring, verify the technical requirements of the sealing assembly.

Important selection criteria include:

1. Inner diameter: 34 mm.

2. Cross-sectional diameter: 3.5 mm.

3. Material: NBR.

4. Nominal hardness: 70 Shore A.

5. Groove dimensions and installation geometry.

6. Operating pressure and extrusion clearance.

7. Operating temperature.

8. Fluid or gas compatibility.

9. Static or dynamic operating conditions.

10. Required dimensional tolerances and material specifications.

An O-ring with the same nominal dimensions but a different material or hardness may exhibit different compression behavior, chemical resistance, and service life.

Typical Applications of NBR 70 Shore A O-rings

NBR O-rings with a 70 Shore A hardness are commonly used in suitably designed industrial sealing systems.

Typical applications may include:

• Hydraulic connections and components.

• Pneumatic assemblies.

• Valve housings.

• Covers and mechanical enclosures.

• Industrial fittings and connectors.

• Lubrication systems.

• Flanged and threaded connections incorporating correctly designed O-ring grooves.

• Industrial equipment maintenance and repair.

These examples describe typical applications of NBR O-rings and do not establish compatibility with any specific machine, vehicle, or equipment model.

Installation and Storage Recommendations

Correct installation is important for achieving reliable sealing performance.

Before installation, clean the O-ring groove and mating surfaces. Remove dirt, metal particles, and other contaminants that could damage the elastomer.

Inspect the installation surfaces for burrs, sharp edges, and scratches.

Install the O-ring without twisting, cutting, or excessive stretching.

Where lubrication is required, use an installation lubricant compatible with NBR and the operating medium.

Avoid using sharp metal tools that may damage the sealing surface.

Store unused O-rings in clean, dry conditions away from direct sunlight, ozone-generating equipment, excessive heat, and chemicals that may degrade the elastomer.

Alternative Designations and Search References

The product may be identified using the following dimensional and material descriptions:

• O-ring NBR 34x3.5 mm 70 Shore A

• NBR 70 O-ring 34x3.5

• O-ring 34x3.5 NBR 70

• Nitrile rubber O-ring 34x3.5 mm

• 34 mm ID 3.5 mm CS NBR O-ring

• O-ring 34x3.5 mm NBR 70 - 100 pieces

• Metric O-ring 34x3.5 mm NBR

These are alternative identification formats, not independently verified manufacturer part numbers or OEM cross-references.

FAQ - NBR 70 Shore A O-ring 34x3.5 mm

1. What are the dimensions of the NBR 34x3.5 mm O-ring?

The nominal inner diameter is 34 mm, and the cross-sectional diameter is 3.5 mm. The calculated nominal outer diameter is 41 mm.

2. What does 70 Shore A mean?

70 Shore A indicates the nominal hardness of the rubber compound. It influences the O-ring's flexibility, compression characteristics, and resistance to deformation under mechanical loading.

3. Is the NBR 70 Shore A O-ring suitable for hydraulic systems?

It may be suitable for hydraulic applications using compatible fluids and correctly designed sealing grooves. Operating pressure, extrusion clearance, and temperature must be verified.

4. Is NBR resistant to engine oil?

NBR is generally compatible with many mineral oil-based lubricants. Compatibility with a particular engine oil formulation and its additives should be checked for the specific rubber compound.

5. Can a 34x3.5 mm O-ring be replaced with a 34x3 mm O-ring?

Not without verifying the groove design. Changing the cross-sectional diameter affects compression and groove filling, potentially resulting in leakage.

6. Is NBR 90 Shore A interchangeable with NBR 70 Shore A?

Not automatically. NBR 90 Shore A is harder and may require different installation conditions and sealing geometry.

7. Can this O-ring be used in dynamic sealing applications?

It may be used in selected dynamic applications when the groove design, lubrication, movement, friction, and operating conditions are appropriate. Static sealing is generally less demanding.

8. How many O-rings are included in one package?

Each package contains 100 NBR O-rings with nominal dimensions of 34x3.5 mm and hardness of 70 Shore A.

NBR 70 Shore A O-ring 34x3.5 mm - Key Technical Information

The NBR 70 Shore A O-ring 34x3.5 mm is an elastomeric sealing ring with a 34 mm inner diameter, 3.5 mm cross-section, and calculated 41 mm outer diameter. Made from nitrile butadiene rubber, it is suitable for properly designed sealing assemblies using compatible media. Each package contains 100 pieces for industrial maintenance, technical servicing, and B2B procurement.

The product is available from simmering.pl, a specialist supplier of industrial seals, O-rings, and bearings.

With stock operations in Lublin, Poland, simmering.pl supplies industrial customers, maintenance departments, repair workshops, and international B2B buyers, with worldwide shipping options.