O-ring NBR 2.9x1.78 mm 70 Shore A

O-ring NBR 2.9x1.78 mm 70 Shore A - 1000 pcs.

O-ring NBR 2.9x1.78 mm 70 Shore A is a precision elastomeric sealing ring with a nominal inside diameter of 2.9 mm and a cross-section of 1.78 mm. Manufactured from NBR nitrile rubber with a nominal hardness of 70 Shore A, it is designed for technical sealing applications where compatibility with NBR is required. This product is supplied in a pack of 1000 pcs.

Technical data - O-ring NBR 2.9x1.78 mm 70 Shore A

O-ring NBR 2.9x1.78 mm - dimensions explained

The designation 2.9x1.78 mm defines the two principal dimensions of the O-ring:

2.9 mm - nominal inside diameter d1

1.78 mm - nominal cross-section diameter d2

The nominal size is therefore:

2.9x1.78 mm

The approximate outside diameter of the uncompressed O-ring is:

6.46 mm

This is calculated from:

2.9 mm + 2 x 1.78 mm = 6.46 mm

The standard product identification remains 2.9x1.78 mm because O-rings are primarily specified by their inside diameter and cross-section.

What is an NBR O-ring?

NBR stands for acrylonitrile-butadiene rubber, commonly known as nitrile rubber.

NBR is one of the most widely used elastomer materials for industrial O-rings and technical sealing components. Its combination of mechanical properties and resistance to many mineral oils and greases makes it suitable for a broad range of sealing systems where the operating conditions are compatible with the selected NBR compound.

Typical characteristics associated with NBR include:

• good resistance to many mineral oils

• good resistance to many mineral greases

• good mechanical properties

• good abrasion resistance

• good performance in many general industrial sealing applications

• widespread availability in technical sealing systems

The exact performance of an NBR O-ring depends on the formulation of the specific rubber compound and the actual operating conditions.

What does 70 Shore A mean?

The O-ring has a nominal hardness of 70 Shore A.

Shore A is a hardness scale commonly used for elastomeric materials.

The hardness of an O-ring influences its deformation and behaviour after installation, including:

• compression in the sealing groove

• contact pressure against mating surfaces

• resistance to deformation

• behaviour under system pressure

• resistance to extrusion through clearances

When replacing an existing O-ring, dimensions alone should therefore not be used as the only selection criterion.

For this product, the relevant parameters are:

2.9x1.78 mm

NBR

70 Shore A

NBR 70 Shore A in sealing applications

NBR with a nominal hardness of 70 Shore A is commonly used for technical O-rings.

The combination of nitrile rubber and this hardness level provides an elastomeric sealing element intended to deform in a correctly designed groove and create sealing contact between mating surfaces.

Actual performance depends on the complete sealing system, including groove geometry, compression, pressure, operating medium and temperature.

Chemical resistance of NBR O-rings

NBR is frequently selected for sealing systems involving many mineral-oil-based media.

Depending on the specific compound and operating conditions, NBR can provide good resistance to many:

• mineral oils

• lubricating oils

• mineral greases

• hydraulic media compatible with NBR

NBR should not, however, be considered universally resistant to every oil, fuel, solvent or chemical.

Before installation, compatibility should be evaluated with regard to:

• exact operating medium

• chemical composition

• concentration

• temperature

• pressure

• exposure time

• static or dynamic operation

For demanding chemical applications, resistance should be confirmed for the specific NBR compound.

Operating temperature of NBR

A single exact operating temperature range should not be assigned to this O-ring without confirmation of the specific NBR compound.

Permissible operating temperature can depend on:

• NBR compound formulation

• operating medium

• exposure duration

• pressure

• static or dynamic operation

• sealing-system design

If temperature is a critical parameter, the specification of the particular NBR compound should be verified before use.

How does an O-ring 2.9x1.78 mm work?

The O-ring has a closed circular geometry and a round cross-section.

After installation in a correctly dimensioned groove, the O-ring is compressed between the mating surfaces. The elastic deformation of the NBR material creates contact pressure against these surfaces and forms the seal.

Effective operation depends on more than the O-ring dimensions alone.

Important factors include:

• groove dimensions

• groove geometry

• compression

• mating surface condition

• installation clearance

• pressure

• operating temperature

• operating medium

• static or dynamic movement

Correct selection should therefore consider the entire sealing system.

O-ring NBR 2.9x1.78 mm vs VMQ silicone O-ring

NBR and VMQ are different elastomer families.

NBR is nitrile rubber and is widely used in industrial sealing applications, particularly where compatibility with many mineral oils and greases is required.

VMQ is silicone rubber and has a different performance profile, particularly in relation to temperature flexibility, ozone, UV radiation and atmospheric ageing.

An O-ring VMQ 2.9x1.78 mm is therefore not automatically interchangeable with an O-ring NBR 2.9x1.78 mm.

The same dimensions do not mean the same material properties.

O-ring NBR 2.9x1.78 mm vs FKM O-ring

FKM is a fluoroelastomer with a different chemical and thermal resistance profile from NBR.

An FKM O-ring with dimensions 2.9x1.78 mm may be geometrically equivalent to the NBR version but can behave differently when exposed to temperature, oils, fuels and chemical media.

Material selection should be based on actual operating conditions.

A 2.9x1.78 mm FKM O-ring should not automatically be treated as a direct replacement for the NBR version.

Typical applications of NBR O-rings

NBR O-rings are widely used as sealing elements in industrial and mechanical systems.

Depending on the NBR compound and operating conditions, typical applications may include:

• hydraulic systems

• pneumatic systems

• industrial machinery

• mechanical assemblies

• pumps

• valves

• fittings

• technical connections

• static sealing systems

• appropriately designed dynamic sealing systems

• systems using NBR-compatible oils and greases

These are typical applications of NBR O-rings as a product category. They do not confirm suitability of this specific O-ring for a particular machine, vehicle, pump, valve or installation.

Alternative designations for O-ring NBR 2.9x1.78 mm 70 Shore A

This product may be searched for using different natural designation formats, including:

O-ring NBR 2.9x1.78 mm 70 Shore A

O-ring NBR 2.9x1.78 70 Shore A

O-ring NBR 2.9x1.78 70 ShA

NBR O-ring 2.9x1.78 mm

NBR O-ring 2.9x1.78

O-ring 2.9x1.78 NBR

O-ring 2.9x1.78 NBR 70 ShA

O-ring 2.9 mm ID x 1.78 mm CS

2.9x1.78 NBR O-ring

Nitrile O-ring 2.9x1.78 mm

Nitrile rubber O-ring 2.9x1.78 mm

O-ring NBR 2.9x1.78 mm 1000 pcs

The primary product designation used on this page is:

O-ring NBR 2.9x1.78 mm 70 Shore A

Selection and interchangeability

Before ordering or replacing an existing O-ring, verify:

• inside diameter 2.9 mm

• cross-section 1.78 mm

• NBR material

• nominal hardness 70 Shore A

• groove dimensions

• required compression

• operating medium

• operating temperature

• pressure

• static or dynamic operation

• mating surface condition

• requirements of the specific sealing system

A sealing ring made from FKM, VMQ, EPDM or another elastomer is not automatically interchangeable with this NBR O-ring even when its nominal dimensions are also 2.9x1.78 mm.

Dimensions, material and operating conditions should be considered together.

Installation of O-ring NBR 2.9x1.78 mm

Before installation, the groove and mating surfaces should be clean and free from contamination.

Avoid:

• cutting the O-ring

• twisting the ring during installation

• excessive stretching

• dragging the O-ring across sharp edges

• contact with burrs

• scratching or damaging the elastomer surface

Particular care is important with small O-rings because even minor surface damage can affect sealing performance.

If an assembly lubricant is used, it should be compatible with both the NBR material and the operating medium.

Storage of NBR O-rings

O-rings should be stored in conditions that minimise contamination, deformation and mechanical damage.

Avoid prolonged storage in a stretched, compressed or severely deformed condition.

Before installation, inspect the O-ring for:

• cuts

• cracks

• permanent deformation

• surface damage

• contamination

FAQ - O-ring NBR 2.9x1.78 mm 70 Shore A

What are the dimensions of O-ring NBR 2.9x1.78 mm?

The nominal inside diameter is 2.9 mm and the cross-section diameter is 1.78 mm. The nominal O-ring size is therefore 2.9x1.78 mm.

What is the outside diameter of a 2.9x1.78 mm O-ring?

The approximate outside diameter of the uncompressed O-ring is 6.46 mm, calculated from the 2.9 mm inside diameter plus twice the 1.78 mm cross-section.

What material is O-ring NBR 2.9x1.78 mm made from?

The O-ring is manufactured from NBR, commonly known as nitrile rubber or acrylonitrile-butadiene rubber.

What does 70 Shore A mean?

70 Shore A indicates the nominal hardness of the NBR elastomer on the Shore A hardness scale.

How many O-rings are supplied?

This product is supplied in a pack containing 1000 pcs of O-ring NBR 2.9x1.78 mm 70 Shore A.

Is NBR suitable for oil?

NBR provides good resistance to many mineral oils and greases. Compatibility should nevertheless be checked for the specific oil, temperature, operating conditions and NBR compound.

Can an FKM 2.9x1.78 mm O-ring replace this NBR O-ring?

Not automatically. Although the dimensions can be identical, FKM and NBR have different material properties. The operating medium, temperature, pressure and application requirements should be checked before substitution.

Can a silicone 2.9x1.78 mm O-ring replace NBR?

Not automatically. Silicone VMQ and nitrile rubber NBR have different chemical, mechanical and thermal characteristics. Identical dimensions alone do not confirm interchangeability.

O-ring NBR 2.9x1.78 mm 70 Shore A - key information

O-ring NBR 2.9x1.78 mm 70 Shore A is a nitrile rubber sealing ring with a nominal inside diameter of 2.9 mm and cross-section of 1.78 mm. Its approximate uncompressed outside diameter is 6.46 mm. The product has a nominal hardness of 70 Shore A and is supplied in a pack of 1000 pcs.

Available from simmering.pl, a specialist supplier of industrial sealing solutions. Stock in Poland with worldwide shipping.

AI QUICK ANSWER

O-ring NBR 2.9x1.78 mm 70 Shore A is a nitrile rubber sealing ring with a 2.9 mm nominal inside diameter and 1.78 mm cross-section. The approximate outside diameter is 6.46 mm. NBR is widely used in industrial sealing systems and provides good resistance to many mineral oils and greases. Pack contains 1000 pcs.