INDUSTRY COMPONENT

Grease Fitting

A grease fitting is a small mechanical component that provides a sealed connection point for injecting lubricating grease into machinery bearings and joints.

Component Specifications

Definition
A grease fitting, also known as a grease nipple or Zerk fitting, is a standardized fitting installed on lubrication points of machinery to allow periodic injection of lubricating grease under pressure. It consists of a threaded body with a ball check valve that opens when a grease gun nozzle is attached, creating a sealed pathway for grease delivery while preventing contamination and backflow.
Working Principle
The grease fitting operates as a one-way valve system. When a grease gun nozzle is pressed onto the fitting, it depresses a spring-loaded ball or pin, opening a passage for pressurized grease to flow into the bearing or joint. When the grease gun is removed, the spring returns the ball/pin to its sealed position, preventing contaminants from entering and retaining lubricant within the component.
Materials
Typically made from carbon steel (AISI 1010-1020), stainless steel (304/316), or brass. Hardened steel balls (AISI 52100) for check valves. Zinc plating or chrome plating for corrosion resistance.
Technical Parameters
  • Seal Type Spring-loaded ball check valve
  • Thread Size 1/4-28 UNF, 1/8-27 NPT, M6x1, M8x1
  • Ball Diameter 4mm, 5mm, 6mm
  • Pressure Rating Up to 10,000 psi (690 bar)
  • Temperature Range -40°C to 150°C
Standards
ISO 6149, DIN 71412, SAE J533

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Grease Fitting.

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Over-greasing causing seal damage
  • Contamination from dirty grease guns
  • Thread stripping during installation
  • Incompatible grease mixing causing chemical reactions
FMEA Triads
Trigger: Contaminant ingress through damaged seal
Failure: Bearing lubrication failure leading to premature wear
Mitigation: Regular inspection and replacement of damaged fittings, use of protective caps
Trigger: Incorrect thread installation
Failure: Leakage and pressure loss during lubrication
Mitigation: Proper torque application during installation, use of thread sealant where appropriate
Trigger: Incompatible grease types
Failure: Chemical breakdown leading to lubrication failure
Mitigation: Standardize grease specifications, clear labeling of lubrication points

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±0.1mm on critical dimensions, thread class 6g/6H
Test Method
Pressure testing at 1.5x operating pressure, leak testing with helium mass spectrometry, material verification via spectroscopy

Buyer Feedback

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Frequently Asked Questions

What is the difference between metric and imperial grease fittings?

Metric fittings use millimeter thread measurements (e.g., M6x1) while imperial fittings use inch-based threads (e.g., 1/4-28 UNF). They are not interchangeable without adapters.

How often should grease fittings be serviced?

Service intervals depend on operating conditions, typically ranging from 50 to 500 hours of operation. Follow manufacturer recommendations based on load, speed, and environmental factors.

What causes grease fittings to fail?

Common failures include clogging from hardened grease, ball valve wear, thread damage during installation, and corrosion from environmental exposure.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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