O-ring NBR 117x3.5 mm 70 Shore A

O-ring NBR 117x3.5 mm 70 Shore A is an elastomeric sealing ring with a nominal inside diameter of 117 mm and a cross-section of 3.5 mm. It is made from nitrile rubber NBR with a nominal hardness of 70 Shore A. Its circular cross-section provides sealing when the O-ring is correctly installed and compressed in a properly designed groove. This size is sold individually, per piece.

Technical data

The nominal outside diameter of 124 mm is derived geometrically from the 117 mm inside diameter and twice the 3.5 mm cross-section.

What does 117x3.5 NBR 70 Shore A mean?

The designation identifies the essential characteristics of the O-ring:

• 117 mm - nominal inside diameter

• 3.5 mm - nominal cross-section diameter

• NBR - nitrile rubber

• 70 Shore A - nominal elastomer hardness on the Shore A scale

For this O-ring, 117x3.5 mm means inside diameter x cross-section. It does not indicate outside diameter x thickness.

NBR 70 Shore A material

NBR, or nitrile butadiene rubber, is one of the most widely used elastomers for technical O-rings. A characteristic property of NBR is its good resistance to many mineral oils and mineral oil-based greases.

The 70 Shore A value specifies the nominal hardness class of the elastomer. Hardness alone does not define all properties of a particular NBR compound.

Actual chemical, thermal and mechanical resistance depends on the specific compound formulation, operating medium, temperature, pressure and sealing system design. For this reason, a specific operating temperature range should not be assigned to this O-ring solely on the basis of the general NBR 70 Shore A designation.

Design and operating principle

The O-ring NBR 117x3.5 mm 70 Shore A is a closed elastomeric ring with a circular 3.5 mm cross-section. It has no additional sealing lip, spring or metal component.

Sealing is achieved through controlled deformation of the O-ring after installation in a correctly designed groove. Compression of the elastomer between mating surfaces creates the sealing effect.

O-rings are commonly used in static sealing arrangements and, with an appropriately engineered sealing system, can also be used in certain dynamic applications. Groove dimensions, compression, material and lubrication conditions must always be selected for the specific application.

Alternative designations and search references

Natural variants of this product designation include:

• O-ring NBR 117x3.5 mm 70 Shore A

• O-ring 117x3.5 NBR 70 Shore A

• NBR O-ring 117x3.5 mm 70 Shore A

• O-ring 117x3.5 NBR 70

• 117x3.5 NBR 70

• O-ring 117 x 3.5 NBR 70

Different forms of notation can describe the same basic combination of nominal dimensions, material and hardness. However, similar designations do not automatically confirm identical tolerances, elastomer compounds or other technical properties between products from different manufacturers.

O-ring NBR 117x3.5 mm 70 Shore A vs other variants

O-rings with nominal dimensions of 117x3.5 mm can be manufactured from different elastomers and in different hardness grades.

An NBR 70 Shore A O-ring should not automatically be replaced with an FKM, EPDM, VMQ or other elastomer O-ring simply because the nominal dimensions are also 117x3.5 mm.

Changing the elastomer can affect compatibility with the operating medium, temperature resistance, ozone resistance, ageing behaviour and environmental resistance. Changing hardness can also affect deformation and sealing behaviour inside the groove.

Identical nominal dimensions therefore do not necessarily mean full interchangeability.

How to select an O-ring NBR 117x3.5 mm 70 Shore A

Before installation, verify:

• 117 mm inside diameter

• 3.5 mm cross-section

• groove dimensions and geometry

• required O-ring compression

• NBR material

• required 70 Shore A hardness

• operating medium

• operating temperature

• pressure

• static or dynamic operating conditions

• compatibility of NBR with the operating medium

• required tolerances, standards and approvals

Two O-rings with nominal dimensions of 117x3.5 mm are not necessarily fully interchangeable. Dimensions, material, hardness and the requirements of the specific sealing system must all be considered.

Applications

NBR O-rings are widely used as sealing elements in appropriately designed technical sealing systems where the properties of the specific NBR compound are compatible with the operating medium and working conditions.

The 117x3.5 mm size alone does not confirm suitability for a specific machine, pump, cylinder, valve, gearbox or other equipment.

When selecting a replacement seal, use the equipment documentation, the specification of the removed O-ring or the engineering parameters of the sealing system.

Installation and handling

Before installation, clean the groove and mating surfaces. Protect the O-ring from cuts, scratches and damage caused by sharp edges, burrs or threads.

Avoid twisting or excessively stretching the O-ring during installation. If an assembly lubricant is required, it must be compatible with both the NBR material and the operating medium.

O-rings should be stored under conditions that limit exposure to light, ozone, excessive heat and other factors that may accelerate elastomer ageing.

FAQ

What are the dimensions of the O-ring NBR 117x3.5 mm 70 Shore A?

The nominal inside diameter is 117 mm and the cross-section is 3.5 mm. The resulting nominal outside diameter is 124 mm.

What does 117x3.5 mm mean?

117 mm is the nominal inside diameter of the O-ring, while 3.5 mm is the nominal diameter of its circular cross-section.

What does NBR mean?

NBR stands for nitrile butadiene rubber, commonly called nitrile rubber. It is an elastomer widely used for technical sealing components.

What does 70 Shore A mean?

70 Shore A specifies the nominal hardness of the elastomer on the Shore A hardness scale.

Is the O-ring NBR 117x3.5 mm 70 Shore A sold individually?

Yes. This O-ring size is sold individually, per piece.

Can an NBR 117x3.5 mm O-ring be replaced with an FKM 117x3.5 mm O-ring?

Not automatically. NBR and FKM are different elastomers with different operating characteristics. Material compatibility with the medium, temperature and other operating conditions must be verified before substitution.

Can NBR 90 Shore A replace NBR 70 Shore A?

Not automatically. A change in hardness affects deformation and sealing behaviour in the groove. The hardness grade should match the requirements of the sealing system unless the alternative has been technically verified.

Is the 117x3.5 mm size alone sufficient to select the correct O-ring?

No. Material, hardness, operating medium, temperature, pressure, groove design and static or dynamic operating conditions must also be considered.

O-ring NBR 117x3.5 mm 70 Shore A - key information

O-ring NBR 117x3.5 mm 70 Shore A is a nitrile rubber sealing ring with a nominal inside diameter of 117 mm and a 3.5 mm cross-section. The elastomer has a nominal hardness of 70 Shore A. Its circular cross-section provides sealing when correctly installed and compressed in a suitable groove. This size is sold individually.

The product is available from the specialist industrial supplier simmering.pl, with stock in Poland. Worldwide shipping is available, as well as assistance with the identification and selection of technical seals.