Oilless Bushing Metallurgy: Solid Lubricants, Bronze, and Composite Layers Under Load
The phrase “oilless bushing” is useful in search and procurement, but it can conceal important engineering differences. Some self-lubricating bushings rely on graphite plugs embedded in cast bronze. Others use a steel-backed, porous bronze interlayer with a PTFE-based sliding surface. A third category is a sintered bronze bearing whose connected porosity stores oil released during service. Each system reduces or eliminates routine external oiling in a defined operating window; none removes the need to control pressure, speed, heat, shaft finish, alignment, and contamination. The metallurgy determines how the bearing carries load, transfers lubricant, and survives wear.