k6 table
| Diameter (mm) | Upper (µm) | Lower (µm) | Example: limit sizes |
|---|---|---|---|
| ≤ 3 | +6 | 0 | Ø3: 3.000 – 3.006 |
| 3–6 | +9 | +1 | Ø6: 6.001 – 6.009 |
| 6–10 | +10 | +1 | Ø10: 10.001 – 10.010 |
| 10–18 | +12 | +1 | Ø18: 18.001 – 18.012 |
| 18–30 | +15 | +2 | Ø30: 30.002 – 30.015 |
| 30–50 | +18 | +2 | Ø50: 50.002 – 50.018 |
| 50–80 | +21 | +2 | Ø80: 80.002 – 80.021 |
| 80–120 | +25 | +3 | Ø120: 120.003 – 120.025 |
| 120–180 | +28 | +3 | Ø180: 180.003 – 180.028 |
| 180–250 | +33 | +4 | Ø250: 250.004 – 250.033 |
| 250–315 | +36 | +4 | Ø315: 315.004 – 315.036 |
| 315–400 | +40 | +4 | Ø400: 400.004 – 400.040 |
| 400–500 | +45 | +5 | Ø500: 500.005 – 500.045 |
How to read it
The letter tells where the tolerance zone sits relative to the nominal size, the number how wide it is (grade IT6). Capitals are for holes, lower case for shafts. Letters before h give shafts smaller than nominal (clearance fits), letters after h larger shafts (transition or interference).
Fits using k6
Other classes
Values computed from the IT grades and fundamental deviations of ISO 286-1, checked against several published tables. For critical designs the standard itself is what counts.