21 mm Internal Retaining Ring (Bore Circlip), DIN 472
For a 21 mm bore, grooved to 22 mm: the internal retaining ring (DIN 472), 1 mm thick. Download it as simplified STEP files.

How these parts are made, and what the levels mean: read the method
- Also searched as: 21 mm circlip
- Model id:
din472-d21
- Standard: DIN 472:2017 · size 21 mm
Files
| Part key | Simplified |
|---|
din472-d21 | STEP |
Dimensions

| Symbol | Name | min | nom | max | Modeled | Rule | Level |
|---|
| s | Ring thickness | | 1 | | 1 | nominal | L1 |
| s_lim | Ring thickness, limits | 0.94 | | 1 | 0.97 | midpoint of min–max | L0 (max: one source) |
| d3 | Free diameter | | 22.5 | | 22.5 | nominal | L1 |
| d3_lim | Free diameter, limits | 22.37 | | 22.92 | 22.645 | midpoint of min–max | L1 |
| a | Lug height | | | 4.2 | 4.2 | single limit (max), modeled at the limit | L1 |
| b | Radial width | | 2.4 ref | | 2.4 | reference value | L1 |
| d5 | Plier hole diameter | 2 | | | 2 | single limit (min), modeled at the limit | L1 |
| d2 | Groove diameter | | 22 | | 22 | nominal | L1 |
| m | Groove width | | 1.1 | | 1.1 | nominal | L1 |
| n | Groove edge margin | 1.5 | | | 1.5 | single limit (min), modeled at the limit | L1 |
Drawing

As a PDF: CC-DIN472-SZ-21.pdf.
The 21 mm internal retaining ring beside the 20 mm and the 22 mm
The 21 mm is number 14, counting from the smallest, of the 17 DIN 472 internal retaining rings published here, from 8 mm to 25 mm.
- Ring thickness (s): 1 mm on the 21 mm internal retaining ring, the same on the 20 mm and the 22 mm.
- Ring thickness, limits (s_lim): 0.94 to 1 mm on the 21 mm internal retaining ring, the same on the 20 mm and the 22 mm.
- Free diameter (d3): 22.5 mm on the 21 mm internal retaining ring, against 21.5 mm on the 20 mm and 23.5 mm on the 22 mm.
- Free diameter, limits (d3_lim): 22.37 to 22.92 mm on the 21 mm internal retaining ring, against 21.37 to 21.92 mm on the 20 mm and 23.37 to 23.92 mm on the 22 mm.
- Lug height (a): up to 4.2 mm on the 21 mm internal retaining ring, the same on the 20 mm and the 22 mm.
- Radial width (b): 2.4 mm (reference) on the 21 mm internal retaining ring, against 2.3 mm (reference) on the 20 mm and 2.5 mm (reference) on the 22 mm.
- Plier hole diameter (d5): at least 2 mm on the 21 mm internal retaining ring, the same on the 20 mm and the 22 mm.
- Groove diameter (d2): 22 mm on the 21 mm internal retaining ring, against 21 mm on the 20 mm and 23 mm on the 22 mm.
Other sizes
Documents
Sources
fasten-it-din472, fasteners-eu-din472, hc-maschinentechnik-din472, seeger-din472. Full citations: the method page and this size's datasheet.
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