O-Ring 18.77x1.78 NBR 70 Shore A

What Is the O-Ring 18.77x1.78 NBR 70 Shore A 100 pcs?

O-Ring 18.77x1.78 NBR 70 Shore A is a technical sealing ring manufactured from NBR (Nitrile Butadiene Rubber, Buna-N). The dimensions 18.77x1.78 mm indicate an inside diameter of 18.77 mm and a cross-section of 1.78 mm. With a hardness of 70 Shore A, the seal combines elasticity with good mechanical resistance. The 100-piece pack is intended for workshops, technical service, machinery maintenance, repairs and small assembly runs requiring a practical supply of identical seals.

Technical Specification

Product Type: O-Ring

Material: NBR (Nitrile Butadiene Rubber, Buna-N)

Hardness: 70 Shore A

Inside Diameter: 18.77 mm

Cross Section: 1.78 mm

Colour: Black

Operating Temperature: Approximately -30°C to +100°C

Chemical Resistance: Mineral oils, mineral-based hydraulic oils, lubricating greases, selected fuels and compatible industrial fluids

Package Quantity: 100 pcs

Applications in Service and Workshop Operations

The O-Ring 18.77x1.78 NBR 70 Shore A is suitable for regular servicing and repair of mechanical, hydraulic and pneumatic components.

Typical applications include:

• Hydraulic fittings
• Pneumatic components
• Valves
• Pumps
• Technical fittings
• Control valves
• Industrial automation
• Machinery components
• Workshop equipment
• Production machinery
• Maintenance and repair operations

Before installation, the groove dimensions, compression ratio and compatibility of NBR with the operating medium should always be verified.

Why Choose NBR 70 Shore A?

NBR 70 Shore A is one of the most commonly used elastomer materials in technical sealing applications. Its widespread use is primarily due to its resistance to mineral oils combined with good mechanical properties.

Important characteristics include:

• Very good resistance to mineral oils
• Good resistance to lubricating greases
• Good abrasion resistance
• Good mechanical strength
• Suitable elasticity
• Reliable sealing performance
• Wide use in hydraulic systems
• Wide use in pneumatic systems

The 70 Shore A hardness provides a practical balance between flexibility and resistance to mechanical deformation.

Hydraulic and Pneumatic Applications

The 18.77x1.78 NBR O-Ring can be used in hydraulic systems operating with compatible mineral oil-based hydraulic fluids.

Its 1.78 mm cross-section also makes it suitable for relatively compact sealing grooves found in pneumatic valves, fittings, distributors and control components.

Final selection should always consider pressure, temperature, operating medium, groove geometry and whether the application is static or dynamic.

Benefits of the 100-Piece Pack

The 100 pcs package is intended for customers who perform regular technical repairs without requiring quantities associated with large-scale manufacturing.

Benefits include:

• Practical quantity for workshop use
• Convenient stock for regular repairs
• Reduced frequency of ordering
• Immediate availability during servicing
• Suitable for repetitive maintenance tasks
• Appropriate quantity for small assembly runs

This package size is specifically targeted at workshops, technical service, maintenance and repair applications.

Repair and Maintenance Applications

For maintenance departments, the O-Ring 18.77x1.78 NBR 70 Shore A can form part of a technical spare-parts inventory for valves, fittings, pumps and other equipment.

Keeping 100 identical seals available allows technicians to replace worn O-rings during planned maintenance or unexpected repairs without having to order individual components each time.

Installation Recommendations

Before installing the O-ring:

• Clean the sealing groove thoroughly
• Inspect the mating surfaces
• Protect the seal from sharp edges
• Avoid excessive stretching
• Do not twist the O-ring during installation
• Use only assembly lubricants compatible with NBR
• Check that the seal is correctly seated in the groove

Particular care should be taken with the 1.78 mm cross-section, as cuts or scratches can significantly reduce sealing performance.

Frequently Asked Questions (FAQ)

What does the size 18.77x1.78 mm mean?
The O-ring has an inside diameter of 18.77 mm and a cross-section diameter of 1.78 mm.

Is the O-Ring 18.77x1.78 NBR suitable for hydraulic oil?
Yes. NBR is commonly used with compatible mineral oil-based hydraulic fluids.

Is the 100-piece pack suitable for machinery servicing?
Yes. It provides a convenient quantity for repetitive maintenance, repairs and replacement of worn seals.

Can this O-ring be used in pneumatic systems?
Yes, provided the groove dimensions, pressure, temperature and operating conditions are suitable for NBR.

Is NBR 70 Shore A resistant to grease?
Yes. NBR offers good resistance to many mineral oil-based lubricating greases.

Frequently Asked Questions from Service Technicians and Mechanics

Can a 1.78 mm cross-section be replaced with a 2 mm O-ring?
Not without checking the sealing groove. The difference in cross-section changes compression and may result in leakage or excessive deformation.

Can the 18.77x1.78 O-ring be used for static sealing?
Yes. With the correct groove design, it can be used in many static sealing applications.

Can the O-ring be lubricated before installation?
Yes. A compatible assembly lubricant can reduce friction and help prevent installation damage.

How can I identify a worn NBR O-ring?
Typical signs include flattening, hardening, cracking, cuts, surface damage and loss of elasticity.

How should NBR O-rings be stored?
Store them in a cool, dry location protected from direct sunlight, ozone, excessive heat and unnecessary mechanical deformation.