circlips

Circlips, also known as snap rings or retaining rings, are a family of fasteners designed to be seated in a groove on a shaft or inside a bore to axially locate components. They come in two main forms: external circlips fitted on shafts and internal circlips fitted in bores.

They are typically made from heat-treated steel, stainless steel, or other alloys and may be coated for corrosion resistance. The ends of an external circlip are on the outer edge of the ring; for an internal circlip the ends are on the inner edge. They are installed and removed with specialized snap ring pliers or similar tools that spread or compress the ring to open and close.

Sizing is determined by the groove dimensions: groove diameter, width, and often the thickness of the ring. Manufacturer data and standards provide compatible combinations. Proper groove machining is essential to ensure retention and avoid stress concentrations.

Standards and usage: Snap rings are standardized in many regions, with specifications provided by international and regional standards. They are widely used in automotive, industrial machinery, gear assemblies, and consumer electronics to provide quick assembly and easy disassembly without additional fasteners.

Selection and limitations: When selecting, considerations include whether retention is axial in one direction, load direction and magnitude, expected service life, environment, temperature, lubrication, corrosion resistance, and whether the groove can tolerate potential deformation. Circlips are not ideal for very high-torque retention or applications with dynamic radial movement beyond intended limits.