When securing components inside a mechanical housing, you need a fastening solution that is reliable, space-saving, and capable of handling high rotational forces. Enter the internal circlip—also frequently called an internal retaining ring.
Though small and often hidden from view, these components are vital to the structural integrity of automotive transmissions, electric motors, and heavy machinery.
What is an Internal Circlip?
An internal circlip is a semi-flexible, engineered metal ring with an open end. Unlike external circlips, which stretch open to fit over a shaft, internal circlips are designed to be compressed inward. They are installed directly inside a cylinder, bore, or pipe housing.
Once fitted into a specially machined groove inside the bore, the ring snaps outward. This creates a strong, rigid shoulder that prevents bearings, pins, or gears from slipping out horizontally.
[Housing Wall]
_______________________
| __ [Groove] __ |
| | | | | |
| | |==[CLIP]==| | | <--- Fits tightly into internal groove
| |__| |__| |
|_______________________|
Key Mechanics and Design Features
- The Lug Holes: Look closely at an internal circlip, and you will notice two small tabs with holes at the open ends. These are lug holes. They allow specialized pliers to grip the ring securely during installation and removal.
- Sizing Rules: Internal circlips are always categorized and purchased by the nominal bore diameter (the inside diameter of the housing), not the diameter of the groove or the uncompressed ring itself.
- Tapered Design: The ring’s width decreases from the top center down to the tips. This specific geometry ensures that the circlip maintains a perfectly circular shape when compressed, distributing pressure evenly across the housing groove.
Our Internal Circlips are available to purchase directly online.
