Use the nominal diameter
The shaft or bore diameter normally gives the circlip designation directly: a 40 mm shaft usually uses A40; a 40 mm bore usually uses J40.
Interactive engineering tool
Circlip Identification Tool
Identify standard external shaft circlips to DIN 471 and internal bore circlips to DIN 472 using the measurements you can obtain from the application, the loose ring or its groove.
431 standard sizes
External A3-A650
Internal J8-J650
Metric dimensions
01
Application
Where does the ring fit?
02
Search method
What can you measure?
Identification results
Closest standard matches
Important: Results are dimensional matches, not final design approval. Verify the application, material, groove condition and load before ordering or installation.
How to measure accurately
Three reliable identification routes
Measure the loose ring
Free diameter and thickness are highly useful together. Do not force a distorted ring closed or open while measuring.
Measure the groove
Groove diameter and width can identify a missing ring. Measure at several points and account for wear, coating and chamfers.
Different retaining ring?
Not every retaining ring is DIN 471 or DIN 472
This tool covers conventional tapered-section circlips with plier holes. It will not positively identify E-clips, crescent rings, spiral retaining rings, round-wire snap rings, self-locking rings, heavy-duty AS/JS rings or custom stampings.
Send Bridge Engineering a photograph →- E-clip / DIN 6799Radially installed onto a shaft; no plier holes.
- Spiral ringTwo or more turns; uniform section; usually no lugs.
- Wire snap ringRound section rather than flat stamped strip.
- Heavy-duty circlipThicker than the normal DIN 471/472 version for the same nominal size.
Browse the complete included size table431 DIN 471 / DIN 472 sizes from 3 mm to 650 mm
| Designation | Application | Nominal | Thickness | Free diameter | Groove diameter | Groove width min. | Pliers group |
|---|
Selection and measurement guidance
Identify the ring and verify the groove
A close dimensional match is only the starting point. Ring family, groove geometry, material, finish and operating load must all be confirmed before a retaining ring is ordered or fitted.
Confirm the retaining-ring family
Establish whether the ring fits an external shaft or an internal bore. E-clips, spiral rings, constant-section rings and tapered-section circlips are not interchangeable simply because a diameter appears similar.
Measure the correct feature
Record the nominal shaft or bore, ring thickness, free diameter and lug or plier-hole details. If the original ring is distorted or missing, prioritise accurate groove measurements and the mating-component diameter.
Check material and finish
Note corrosion exposure, washdown, temperature and any food, marine or electrical requirements. Carbon steel, stainless grades and protective finishes can have different availability and performance.
Verify the groove and application
Confirm groove diameter, width, depth, edge distance and condition against current manufacturer data. Axial load, rotational speed, shock, fatigue and installation method also affect suitability.
Workshop checklist
Circlip identification checklist
Record these details and include photographs of the ring, groove and application where possible.
- External shaft or internal bore location
- Retaining-ring family or visual style
- Nominal shaft or bore diameter
- Ring thickness and free diameter
- Lug span and plier-hole details
- Groove diameter, width, depth and condition
- Material, finish and operating environment
- Axial load, speed, duty and quantity
Safety note: Do not reuse a ring that is distorted, cracked, heavily corroded or outside manufacturer limits. Safety-critical selections require current manufacturer data and competent engineering verification.
Technical basis
Reference data and limitations
Dimensional data is based on manufacturer-published standard-ring tables for DIN 471 shaft rings and DIN 472 bore rings. Standard dimensions can be revised and manufacturers may apply permitted tolerances differently.
Source references: Seeger-Orbis DIN 471/472 overview and Rotor Clip DIN-standard retaining rings. Always verify the latest manufacturer data for safety-critical applications.