Retention
Retaining rings: grooves in shafts and bores
DIN 471 and DIN 472 with the dimensions that go to the machine: groove bottom Ø with h11/H11 tolerance, width, minimum distance to the loaded face — and the check that usually decides the design, which is the shaft's shoulder of material, not the ring.
1. Standard and size
External ring: the groove is machined on the shaft and the ring goes on expanded, gripping the groove bottom.- Nominal
- 25
- Thickness s
- 1.20
- Bottom d2
- 23.90
- Width m
- 1.30
2. Groove as machined
Left blank, it uses the standard's value. Fill it in to check a groove that already exists, or a deliberate deviation.3. Load (optional)
The stress comes out as F/A, with no safety factor built in — yours goes on top. This checks the shaft or the bore, not the ring: the ring's capacity comes from the manufacturer's catalogue.Bottom Ø d2
23.90
mm h11
Width m
1.30
mm min.
Depth
0.55
mm on the radius
Shear area
128
mm² (π·d2·n)
- Note: Axial play of 0.1 mm. The standard is born with play — the groove width is the ring thickness plus 0.1 mm in this range. A retaining ring is not a precise axial locating element.
Groove dimensions
| Ø of the shaft d1 | 25.00 mm | |
|---|---|---|
| Groove bottom Ø d2 | 23.90 mm | h11 0 / −0.13 |
| Groove width m | 1.30 mm | +0.14 / 0 usual |
| Depth on the radius | 0.55 mm | |
| Minimum distance to the face n | 1.70 mm | standard |
| Ring thickness s | 1.20 mm | |
| Axial play | 0.10 mm | m − s |
| Ring grip on the bottom | 0.70 mm | on the diameter |
| Opening during assembly | 1.80 mm | on the diameter |
| Shear area of the shoulder | 128 mm² | π · d2 · n |
| Bearing area on the wall | 42 mm² | ring × wall |
The DXF carries the groove rectangle on layer RASGO and the centre line on EIXO, for a revolved cut. The corners come out sharp: the groove corner is the ring's bearing face, and rounding it lets the ring tilt under load.
What this calculation does — and what it doesn't
We don't give the ring's load capacity
The load a retaining ring takes comes from manufacturer testing: it depends on the compound, the heat treatment and the stamping process. No open formula reproduces that number honestly, so it doesn't appear here.
That value is in the manufacturer's catalogue, by size and by material, and that's where it should come from.
We do give the areas and the stresses
What follows from geometry alone: the cylindrical shear area of the shoulder of material (π · d2 · n), the ring's bearing area against the groove wall, and the stress your load produces in them — plain F/A, with no safety factor built in.
The factor is yours and goes on afterwards. Shear yield is taken as Re/√3, by the von Mises criterion.
What fails first is usually the shaft
In a badly sized assembly, the usual failure mode isn't the ring breaking: it's the shoulder of material between the groove and the shaft end shearing off like a washer, taking the ring with it.
That's why the standard's n distance is not a suggestion. It sizes exactly that area — and it's the first dimension lost when someone shortens the shaft.
A retaining ring doesn't locate
The standard is born with play: the groove width is the ring thickness plus 0.10 mm (up to 1.75 thick) or plus 0.15 mm. The retained assembly has that play to hammer with on every load reversal.
If the design can't take axial play, the answer is a wave washer, a selected spacer or another element — not a tighter groove, which would prevent assembly.
DIN 471 — external ring, for shafts
86 sizes, from Ø3 to Ø300 mm. The groove is machined into the shaft, so d2 < d1. The ring goes on expanded and seats gripping the bottom.
| Shaft Ø | s | d3 | d2 | m min. | n min. | Depth |
|---|---|---|---|---|---|---|
| 3 | 0.40 | 2.70 | 2.80 | 0.50 | 0.30 | 0.10 |
| 4 | 0.40 | 3.70 | 3.80 | 0.50 | 0.30 | 0.10 |
| 5 | 0.60 | 4.70 | 4.80 | 0.70 | 0.30 | 0.10 |
| 6 | 0.70 | 5.60 | 5.70 | 0.80 | 0.50 | 0.15 |
| 7 | 0.80 | 6.50 | 6.70 | 0.90 | 0.50 | 0.15 |
| 8 | 0.80 | 7.40 | 7.60 | 0.90 | 0.60 | 0.20 |
| 9 | 1.00 | 8.40 | 8.60 | 1.10 | 0.60 | 0.20 |
| 10 | 1.00 | 9.30 | 9.60 | 1.10 | 0.60 | 0.20 |
| 11 | 1.00 | 10.20 | 10.50 | 1.10 | 0.80 | 0.25 |
| 12 | 1.00 | 11.00 | 11.50 | 1.10 | 0.80 | 0.25 |
| 13 | 1.00 | 11.90 | 12.40 | 1.10 | 0.90 | 0.30 |
| 14 | 1.00 | 12.90 | 13.40 | 1.10 | 0.90 | 0.30 |
| 15 | 1.00 | 13.80 | 14.30 | 1.10 | 1.10 | 0.35 |
| 16 | 1.00 | 14.70 | 15.20 | 1.10 | 1.20 | 0.40 |
| 17 | 1.00 | 15.70 | 16.20 | 1.10 | 1.20 | 0.40 |
| 18 | 1.20 | 16.50 | 17.00 | 1.30 | 1.50 | 0.50 |
| 19 | 1.20 | 17.50 | 18.00 | 1.30 | 1.50 | 0.50 |
| 20 | 1.20 | 18.50 | 19.00 | 1.30 | 1.50 | 0.50 |
| 21 | 1.20 | 19.50 | 20.00 | 1.30 | 1.50 | 0.50 |
| 22 | 1.20 | 20.50 | 21.00 | 1.30 | 1.50 | 0.50 |
| 24 | 1.20 | 22.20 | 22.90 | 1.30 | 1.70 | 0.55 |
| 25 | 1.20 | 23.20 | 23.90 | 1.30 | 1.70 | 0.55 |
| 26 | 1.20 | 24.20 | 24.90 | 1.30 | 1.70 | 0.55 |
| 28 | 1.50 | 25.90 | 26.60 | 1.60 | 2.10 | 0.70 |
| 29 | 1.50 | 26.90 | 27.60 | 1.60 | 2.10 | 0.70 |
| 30 | 1.50 | 27.90 | 28.60 | 1.60 | 2.10 | 0.70 |
| 32 | 1.50 | 29.60 | 30.30 | 1.60 | 2.60 | 0.85 |
| 34check | 1.50 | 31.50 | 32.30 | 1.60 | 2.60 | 0.85 |
| 35 | 1.50 | 32.20 | 33.00 | 1.60 | 3.00 | 1.00 |
| 36 | 1.75 | 33.20 | 34.00 | 1.85 | 3.00 | 1.00 |
| 38 | 1.75 | 35.20 | 36.00 | 1.85 | 3.00 | 1.00 |
| 40 | 1.75 | 36.50 | 37.50 | 1.85 | 3.80 | 1.25 |
| 42 | 1.75 | 38.50 | 39.50 | 1.85 | 3.80 | 1.25 |
| 45 | 1.75 | 41.50 | 42.50 | 1.85 | 3.80 | 1.25 |
| 48check | 1.75 | 44.50 | 45.50 | 1.85 | 3.80 | 1.25 |
| 50 | 2.00 | 45.80 | 47.00 | 2.15 | 4.50 | 1.50 |
| 52 | 2.00 | 47.80 | 49.00 | 2.15 | 4.50 | 1.50 |
| 55 | 2.00 | 50.80 | 52.00 | 2.15 | 4.50 | 1.50 |
| 56 | 2.00 | 51.80 | 53.00 | 2.15 | 4.50 | 1.50 |
| 58 | 2.00 | 53.80 | 55.00 | 2.15 | 4.50 | 1.50 |
| 60 | 2.00 | 55.80 | 57.00 | 2.15 | 4.50 | 1.50 |
| 62 | 2.00 | 57.80 | 59.00 | 2.15 | 4.50 | 1.50 |
| 63 | 2.00 | 58.80 | 60.00 | 2.15 | 4.50 | 1.50 |
| 65 | 2.50 | 60.80 | 62.00 | 2.65 | 4.50 | 1.50 |
| 68 | 2.50 | 63.50 | 65.00 | 2.65 | 4.50 | 1.50 |
| 70 | 2.50 | 65.50 | 67.00 | 2.65 | 4.50 | 1.50 |
| 72 | 2.50 | 67.50 | 69.00 | 2.65 | 4.50 | 1.50 |
| 75 | 2.50 | 70.50 | 72.00 | 2.65 | 4.50 | 1.50 |
| 78 | 2.50 | 73.50 | 75.00 | 2.65 | 4.50 | 1.50 |
| 80 | 2.50 | 74.50 | 76.50 | 2.65 | 5.30 | 1.75 |
| 82 | 2.50 | 76.50 | 78.50 | 2.65 | 5.30 | 1.75 |
| 85 | 3.00 | 79.50 | 81.50 | 3.15 | 5.30 | 1.75 |
| 88 | 3.00 | 82.50 | 84.50 | 3.15 | 5.30 | 1.75 |
| 90 | 3.00 | 84.50 | 86.50 | 3.15 | 5.30 | 1.75 |
| 95 | 3.00 | 89.50 | 91.50 | 3.15 | 5.30 | 1.75 |
| 100 | 3.00 | 94.50 | 96.50 | 3.15 | 5.30 | 1.75 |
| 105 | 4.00 | 98.00 | 101.00 | 4.15 | 6.00 | 2.00 |
| 110 | 4.00 | 103.00 | 106.00 | 4.15 | 6.00 | 2.00 |
| 115 | 4.00 | 108.00 | 111.00 | 4.15 | 6.00 | 2.00 |
| 120 | 4.00 | 113.00 | 116.00 | 4.15 | 6.00 | 2.00 |
| 125 | 4.00 | 118.00 | 121.00 | 4.15 | 6.00 | 2.00 |
| 130 | 4.00 | 123.00 | 126.00 | 4.15 | 6.00 | 2.00 |
| 135 | 4.00 | 128.00 | 131.00 | 4.15 | 6.00 | 2.00 |
| 140check | 4.00 | 133.00 | 136.00 | 4.15 | 6.00 | 2.00 |
| 145 | 4.00 | 138.00 | 141.00 | 4.15 | 6.00 | 2.00 |
| 150 | 4.00 | 142.00 | 145.00 | 4.15 | 7.50 | 2.50 |
| 155 | 4.00 | 146.00 | 150.00 | 4.15 | 7.50 | 2.50 |
| 160 | 4.00 | 151.00 | 155.00 | 4.15 | 7.50 | 2.50 |
| 165 | 4.00 | 155.50 | 160.00 | 4.15 | 7.50 | 2.50 |
| 170check | 4.00 | 160.50 | 165.00 | 4.15 | 7.50 | 2.50 |
| 175 | 4.00 | 165.50 | 170.00 | 4.15 | 7.50 | 2.50 |
| 180check | 4.00 | 170.50 | 175.00 | 4.15 | 7.50 | 2.50 |
| 185 | 4.00 | 175.50 | 180.00 | 4.15 | 7.50 | 2.50 |
| 190 | 4.00 | 180.50 | 185.00 | 4.15 | 7.50 | 2.50 |
| 195 | 4.00 | 185.50 | 190.00 | 4.15 | 7.50 | 2.50 |
| 200 | 4.00 | 190.50 | 195.00 | 4.15 | 7.50 | 2.50 |
| 210 | 5.00 | 198.00 | 204.00 | 5.15 | 9.00 | 3.00 |
| 220 | 5.00 | 208.00 | 214.00 | 5.15 | 9.00 | 3.00 |
| 230 | 5.00 | 218.00 | 224.00 | 5.15 | 9.00 | 3.00 |
| 240 | 5.00 | 228.00 | 234.00 | 5.15 | 9.00 | 3.00 |
| 250 | 5.00 | 238.00 | 244.00 | 5.15 | 9.00 | 3.00 |
| 260 | 5.00 | 245.00 | 252.00 | 5.15 | 12.00 | 4.00 |
| 270 | 5.00 | 255.00 | 262.00 | 5.15 | 12.00 | 4.00 |
| 280 | 5.00 | 265.00 | 272.00 | 5.15 | 12.00 | 4.00 |
| 290 | 5.00 | 275.00 | 282.00 | 5.15 | 12.00 | 4.00 |
| 300 | 5.00 | 285.00 | 292.00 | 5.15 | 12.00 | 4.00 |
DIN 472 — internal ring, for bores
88 sizes, from Ø8 to Ø300 mm. The groove is machined outward from the bore, so d2 > d1. The ring goes in compressed and springs out against the bottom.
| Bore Ø | s | d3 | d2 | m min. | n min. | Depth |
|---|---|---|---|---|---|---|
| 8 | 0.80 | 8.70 | 8.40 | 0.90 | 0.60 | 0.20 |
| 9 | 0.80 | 9.80 | 9.40 | 0.90 | 0.60 | 0.20 |
| 10 | 1.00 | 10.80 | 10.40 | 1.10 | 0.60 | 0.20 |
| 11 | 1.00 | 11.80 | 11.40 | 1.10 | 0.60 | 0.20 |
| 12 | 1.00 | 13.00 | 12.50 | 1.10 | 0.80 | 0.25 |
| 13 | 1.00 | 14.10 | 13.60 | 1.10 | 0.90 | 0.30 |
| 14 | 1.00 | 15.10 | 14.60 | 1.10 | 0.90 | 0.30 |
| 15 | 1.00 | 16.20 | 15.70 | 1.10 | 1.10 | 0.35 |
| 16 | 1.00 | 17.30 | 16.80 | 1.10 | 1.20 | 0.40 |
| 17 | 1.00 | 18.30 | 17.80 | 1.10 | 1.20 | 0.40 |
| 18 | 1.00 | 19.50 | 19.00 | 1.10 | 1.50 | 0.50 |
| 19 | 1.00 | 20.50 | 20.00 | 1.10 | 1.50 | 0.50 |
| 20 | 1.00 | 21.50 | 21.00 | 1.10 | 1.50 | 0.50 |
| 21 | 1.00 | 22.50 | 22.00 | 1.10 | 1.50 | 0.50 |
| 22 | 1.00 | 23.50 | 23.00 | 1.10 | 1.50 | 0.50 |
| 24 | 1.20 | 25.90 | 25.20 | 1.30 | 1.80 | 0.60 |
| 25 | 1.20 | 26.90 | 26.20 | 1.30 | 1.80 | 0.60 |
| 26 | 1.20 | 27.90 | 27.20 | 1.30 | 1.80 | 0.60 |
| 28 | 1.20 | 30.10 | 29.40 | 1.30 | 2.10 | 0.70 |
| 30 | 1.20 | 32.10 | 31.40 | 1.30 | 2.10 | 0.70 |
| 31 | 1.20 | 33.40 | 32.70 | 1.30 | 2.60 | 0.85 |
| 32 | 1.20 | 34.40 | 33.70 | 1.30 | 2.60 | 0.85 |
| 34 | 1.50 | 36.50 | 35.70 | 1.60 | 2.60 | 0.85 |
| 35 | 1.50 | 37.80 | 37.00 | 1.60 | 3.00 | 1.00 |
| 36 | 1.50 | 38.80 | 38.00 | 1.60 | 3.00 | 1.00 |
| 37 | 1.50 | 39.80 | 39.00 | 1.60 | 3.00 | 1.00 |
| 38 | 1.50 | 40.80 | 40.00 | 1.60 | 3.00 | 1.00 |
| 40 | 1.75 | 43.50 | 42.50 | 1.85 | 3.80 | 1.25 |
| 42 | 1.75 | 45.50 | 44.50 | 1.85 | 3.80 | 1.25 |
| 45 | 1.75 | 48.50 | 47.50 | 1.85 | 3.80 | 1.25 |
| 47 | 1.75 | 50.50 | 49.50 | 1.85 | 3.80 | 1.25 |
| 48 | 1.75 | 51.50 | 50.50 | 1.85 | 3.80 | 1.25 |
| 50 | 2.00 | 54.20 | 53.00 | 2.15 | 4.50 | 1.50 |
| 52 | 2.00 | 56.20 | 55.00 | 2.15 | 4.50 | 1.50 |
| 55 | 2.00 | 59.20 | 58.00 | 2.15 | 4.50 | 1.50 |
| 56 | 2.00 | 60.20 | 59.00 | 2.15 | 4.50 | 1.50 |
| 58 | 2.00 | 62.20 | 61.00 | 2.15 | 4.50 | 1.50 |
| 60 | 2.00 | 64.20 | 63.00 | 2.15 | 4.50 | 1.50 |
| 62 | 2.00 | 66.20 | 65.00 | 2.15 | 4.50 | 1.50 |
| 63 | 2.00 | 67.20 | 66.00 | 2.15 | 4.50 | 1.50 |
| 65 | 2.50 | 69.20 | 68.00 | 2.65 | 4.50 | 1.50 |
| 68 | 2.50 | 72.50 | 71.00 | 2.65 | 4.50 | 1.50 |
| 70 | 2.50 | 74.50 | 73.00 | 2.65 | 4.50 | 1.50 |
| 72check | 2.50 | 76.50 | 75.00 | 2.65 | 4.50 | 1.50 |
| 75 | 2.50 | 79.50 | 78.00 | 2.65 | 4.50 | 1.50 |
| 78 | 2.50 | 82.50 | 81.00 | 2.65 | 4.50 | 1.50 |
| 80 | 2.50 | 85.50 | 83.50 | 2.65 | 5.30 | 1.75 |
| 82check | 2.50 | 87.50 | 85.50 | 2.65 | 5.30 | 1.75 |
| 85 | 3.00 | 90.50 | 88.50 | 3.15 | 5.30 | 1.75 |
| 88 | 3.00 | 93.50 | 91.50 | 3.15 | 5.30 | 1.75 |
| 90 | 3.00 | 95.50 | 93.50 | 3.15 | 5.30 | 1.75 |
| 92 | 3.00 | 97.50 | 95.50 | 3.15 | 5.30 | 1.75 |
| 95 | 3.00 | 100.50 | 98.50 | 3.15 | 5.30 | 1.75 |
| 98 | 3.00 | 103.50 | 101.50 | 3.15 | 5.30 | 1.75 |
| 100 | 3.00 | 105.50 | 103.50 | 3.15 | 5.30 | 1.75 |
| 102 | 4.00 | 108.00 | 106.00 | 4.15 | 6.00 | 2.00 |
| 105check | 4.00 | 112.00 | 109.00 | 4.15 | 6.00 | 2.00 |
| 108 | 4.00 | 115.00 | 112.00 | 4.15 | 6.00 | 2.00 |
| 110 | 4.00 | 117.00 | 114.00 | 4.15 | 6.00 | 2.00 |
| 112 | 4.00 | 119.00 | 116.00 | 4.15 | 6.00 | 2.00 |
| 115 | 4.00 | 122.00 | 119.00 | 4.15 | 6.00 | 2.00 |
| 120 | 4.00 | 127.00 | 124.00 | 4.15 | 6.00 | 2.00 |
| 125 | 4.00 | 132.00 | 129.00 | 4.15 | 6.00 | 2.00 |
| 130 | 4.00 | 137.00 | 134.00 | 4.15 | 6.00 | 2.00 |
| 135 | 4.00 | 142.00 | 139.00 | 4.15 | 6.00 | 2.00 |
| 140 | 4.00 | 147.00 | 144.00 | 4.15 | 6.00 | 2.00 |
| 145check | 4.00 | 152.00 | 149.00 | 4.15 | 6.00 | 2.00 |
| 150 | 4.00 | 158.00 | 155.00 | 4.15 | 7.50 | 2.50 |
| 155 | 4.00 | 164.00 | 160.00 | 4.15 | 7.50 | 2.50 |
| 160 | 4.00 | 169.00 | 165.00 | 4.15 | 7.50 | 2.50 |
| 165 | 4.00 | 174.50 | 170.00 | 4.15 | 7.50 | 2.50 |
| 170 | 4.00 | 179.50 | 175.00 | 4.15 | 7.50 | 2.50 |
| 175 | 4.00 | 184.50 | 180.00 | 4.15 | 7.50 | 2.50 |
| 180 | 4.00 | 189.50 | 185.00 | 4.15 | 7.50 | 2.50 |
| 185 | 4.00 | 194.50 | 190.00 | 4.15 | 7.50 | 2.50 |
| 190 | 4.00 | 199.50 | 195.00 | 4.15 | 7.50 | 2.50 |
| 195 | 4.00 | 204.50 | 200.00 | 4.15 | 7.50 | 2.50 |
| 200 | 4.00 | 209.50 | 205.00 | 4.15 | 7.50 | 2.50 |
| 210 | 5.00 | 222.00 | 216.00 | 5.15 | 9.00 | 3.00 |
| 220 | 5.00 | 232.00 | 226.00 | 5.15 | 9.00 | 3.00 |
| 230 | 5.00 | 242.00 | 236.00 | 5.15 | 9.00 | 3.00 |
| 240 | 5.00 | 252.00 | 246.00 | 5.15 | 9.00 | 3.00 |
| 250 | 5.00 | 262.00 | 256.00 | 5.15 | 9.00 | 3.00 |
| 260 | 5.00 | 275.00 | 268.00 | 5.15 | 12.00 | 4.00 |
| 270 | 5.00 | 285.00 | 278.00 | 5.15 | 12.00 | 4.00 |
| 280 | 5.00 | 295.00 | 288.00 | 5.15 | 12.00 | 4.00 |
| 290 | 5.00 | 305.00 | 298.00 | 5.15 | 12.00 | 4.00 |
| 300 | 5.00 | 315.00 | 308.00 | 5.15 | 12.00 | 4.00 |
Where this table comes from
Unlike a regular series, DIN 471/472 is irregular size by size: s, d2, m and n follow no closed progression, and an error here doesn't leak — it releases the ring under load. That's why the table was built by cross-checking two independent sources for each standard, rather than transcribing one.
The dimensions that go to the machine — d2 and m — matched on every common row of DIN 471. The cross-check also caught errors in both sources: sizes where the stated thickness didn't agree with the groove width, and a groove bottom diameter that broke the progression of its neighbours. The 9 rows where the sources disagreed are flagged check, and the tool explains the disagreement when you select one of them.
Even so: check against the manufacturer's catalogue before releasing a drawing. This is a starting point, not a certificate.