What is a bushing?

Bushings or plain bearings are mechanical components used to reduce friction between rotating shafts and stationary support members. Bushings are designed to slide over rods to ensure low-friction motion. 

A bushing will often rely on soft metal or plastic and an oil film to support the rotating shaft on a hardened shaft journal. Bushings are commonly made from several different materials including dry-running plastic, wood, babbitt, alloys of bronze such as aluminium nickel, phosphor silicon and more. 

Bushings are also known as journal bearings, sleeve bearings or sliding bearings and have no rolling elements. 

Benefits of bushings

Bushings are self-lubricating meaning that they are low-maintenance components. These components are excellent for minimising energy use, noise, wear and shock absorption. 

Common types of bushings

Bushings or plain bearings come in many different types and are used in various industrial operations. Some common types include:

• Journal bearings: These are used to support the linear motion of engine crankshafts in large turbomachines
• Spherical bearings: These are commonly used in linkages and other applications involving angular rotation
• Drill jig bushings: These are often used as guidance in precision metal drilling operations
• Hydrodynamic and babbitted journal bearings: Journal bearings are often used in large industrial turbomachines
• Sleeve bearings: These are generally used to support linear and rotary motion equally 

Typical bushing applications 

Plain bearings or bushings are critical in applications where bearing failure can have severe consequences. Some common applications of bushings include:

• Turbomachines
• Low-speed shafting applications (e.g. ship propeller shafts)
• Engines
• Intermittent motion applications 
• Linear motion applications