Retaining Rings (Circlips) / Snap Rings for Shafts & Bores
In rotating equipment, “small axial movement” is rarely small: a bearing that walks, a gear that shifts, or a seal that loses its running position can turn into fretting, heat, and accelerated wear. Retaining rings (circlips / snap rings / C-clips) are designed to control axial location with a defined groove interface—so assembly stays serviceable, repeatable, and traceable on the drawing. When specified to the correct standard (DIN 471 / DIN 472 / DIN 6799) and matched to the right material temper, they help prevent ring pop-out, groove deformation, and fatigue cracking under vibration and cyclic thrust loads—common failure modes in motors, gearboxes, pumps, and sheet-metal subassemblies.
- Match DIN 471/472 groove geometry
- Offer external, internal, E-clip types
- Reduce axial walk-out risk
- Support radial or axial assembly
- Choose spring steel or PH stainless
- Provide MTR / CoC traceability
Technical Specifications
Product Name
Spiral / Wire Snap Rings (Optional variants)
Standards
Per customer spec / equivalent standards
Material
Spring steel; Stainless; Phosphor bronze; Beryllium copper (high-end electrical)
Grades
Spring temper; conductive alloys
Diameter Range
Application-specific
Surface Finish
Bright/oiled; Passivated
Certifications
MTR / CoC per request
1: Ring “pops out” during vibration or shock
Root causes (field reality): groove depth too shallow; groove diameter tolerance drift; wrong ring type (external used where internal is required); excessive installation over-expansion creates permanent set.
Engineering response: specify external vs internal by where the groove is located (shaft vs bore), then lock the groove geometry to the standard (DIN 471 / DIN 472). For high shock, consider designs with better seating and controlled chamfers; for assembly lines needing speed, consider E-clips where radial installation is preferred.
2: Groove damage and thrust-face fretting
What happens: repeated micro-motion under cyclic axial load causes fretting on the groove flank; the groove can “mushroom,” reducing effective retention.
Engineering response: add a hardened thrust washer / shim washer as a bearing surface when the retained component thrusts directly against the ring; control axial stack-up and surface hardness on the groove flank; use spiral rings when 360° contact is required (better load distribution than two-lug rings).
3: Corrosion + fatigue = cracked rings
What happens: spring steel rings in wet or salt environments corrode at the highest-stress region near the lugs/ends; cracks initiate under cyclic expansion/compression.
Engineering response: specify stainless (304/316) for corrosion, or PH stainless (17-7 PH / 15-7 Mo) when both corrosion resistance and higher spring strength retention are needed. For plated spring steel, evaluate hydrogen embrittlement risk and consider phosphate/oil or mechanical plating routes depending on the programme.
4: Assembly errors (wrong tooling, wrong deformation)
What happens: technicians use screwdrivers or over-open pliers, scoring the groove and plastically deforming the ring—then the ring “looks seated” but isn’t.
Engineering response: define the assembly method on the work instruction: axial assembly (DIN 471/472) using correct pliers; radial assembly (DIN 6799 E-clips) when access is limited. E-type circlips are pushed into a shaft groove and are commonly used on small shafts.
Note: Values below are examples for drawing/BOM clarity and “dimensions” search intent. For full selection, specify standard + nominal size + material + finish.
Example A — DIN 471 External Retaining Rings (for Shafts)
| Nominal Shaft d1 (mm) | Ring thickness s (mm) | Groove diameter d2 (mm) | Groove width m1 (mm) | Reference n (mm) |
|---|---|---|---|---|
| 10 | 1.0 | 9.4 | 1.1 | 0.5 |
| 20 | 1.2 | 19.2 | 1.3 | 0.7 |
| 30 | 1.5 | 29.0 | 1.6 | 0.9 |
| 40 | 1.75 | 38.7 | 1.9 | 1.1 |
Example B — DIN 472 Internal Retaining Rings (for Bores)
| Nominal Bore d1 (mm) | Ring thickness s (mm) | Groove diameter d2 (mm) | Groove width m (mm) | Groove depth t (mm) |
|---|---|---|---|---|
| 10 | 1.0 | 10.4 | 1.1 | 0.6 |
| 20 | 1.0 | 21.0 | 1.1 | 1.5 |
| 30 | 1.2 | 31.4 | 1.3 | 2.1 |
| 38 | 1.5 | 40.0 | 1.6 | 3.0 |
Example C — DIN 6799 E-Clips (E-Rings / Radial Assembly)
| Nominal size d1 (mm) | Ring thickness s (mm) | Groove diameter d2 (mm) | Overall d3 (mm) | Groove width m (mm) | Groove depth t (mm) |
|---|---|---|---|---|---|
| 10 | 1.2 | 11.5 | 20.0 | 1.3 | 1.7 |
| 20 | 1.75 | 23.0 | 38.0 | 1.9 | 2.7 |
| 30 | 2.0 | 33.5 | 54.0 | 2.2 | 4.0 |
1) Confirm selection before installation
External vs internal: External retaining rings (DIN 471) seat on a shaft groove; internal retaining rings (DIN 472) seat in a bore groove. Mixing them is a common cause of “looks installed” but fails in service.
E-clip vs circlip: Use DIN 6799 E-clips when you need radial assembly and fast installation on smaller shafts; use DIN 471/472 when axial assembly and defined lug seating are preferred.
2) Groove readiness checks (the real pass/fail)
Check groove width and depth against the standard table on the drawing; burrs or plating nodules at the groove edges prevent full seating.
Add a lead-in chamfer where appropriate; sharp edges can score the ring and initiate fatigue cracks.
If axial thrust is significant, consider a washer (thrust surface) between the component and ring to reduce fretting and groove flank wear.
3) Tooling and deformation control
Use correct retaining-ring pliers with matching tip diameter; avoid screwdrivers or over-spreading.
Do not over-expand external rings or over-compress internal rings—plastic set reduces retention force and can cause ring rotation or walk-out.
Apply light Lubrication (thin oil film) on the groove for stainless-on-stainless to reduce galling during installation; avoid heavy grease that masks incomplete seating.
4) System-level notes (Torque / Preload / Hole Clearance)
Retaining rings do not create preload; Torque and Preload are controlled by the fastener that generates clamp load elsewhere in the assembly.
If the retained part is bolted and requires Washers, check hole clearance (ISO 273) for the bolted joint separately; do not assume the retaining ring compensates for poor joint geometry.
5) Final verification
Visually confirm the ring is fully seated in the groove all around (no “high spot”).
For safety-critical assemblies, add a tactile check or go/no-go gauge for groove seating depth.
Related Products
FAQ
What is the difference between retaining rings, circlips, and snap rings?
They are commonly used names for the same class of groove-seated fasteners that prevent axial movement on shafts or in bores. “Circlips” is widely used in Europe/Asia, “snap rings” is common in MRO, and “retaining rings” is the standard B2B term used on drawings and purchasing specs.
How do I choose between DIN 471 and DIN 472?
Use DIN 471 for external retaining rings on shafts and DIN 472 for internal retaining rings in bores. The decision is defined by where the groove is machined—shaft groove vs bore groove—not by the assembly preference.
When should I use DIN 6799 E-clips instead of standard circlips?
Use DIN 6799 E-clips when you need radial installation and fast assembly, typically on smaller shafts. They are pushed into the groove rather than expanded over the shaft end, which can simplify assembly where axial access is limited.
What information should I put on the PO or drawing to avoid wrong parts?
Specify type (external/internal/E-clip), standard (DIN 471/472/6799), nominal size, material/grade, and finish. Also include groove dimensions or reference the standard groove table so the supplier can verify fit and seating.
Which material is recommended for corrosion resistance and fatigue life?
For corrosion, specify 304/316 stainless; for a higher strength spring response with corrosion resistance, specify PH stainless (17-7 PH / 15-7 Mo). For general industrial use where cost and spring performance dominate, carbon spring steel (65Mn/SK5) with phosphate/oil is common, but it must be protected from corrosive environments.