F8/h7 fit — Close running fit (shaft basis)
ISO 286 shaft-basis clearance fit. Enter a nominal size to get the limits.
Unit
Result
Ø25.000 F8/h7Clearance fit
| Upper | Lower | Max | Min | Tol. | |
|---|---|---|---|---|---|
| Hole F8 | +0.053 | +0.020 | 25.053 | 25.020 | |
| Shaft h7 | 0 | −0.021 | 25.000 | 24.979 |
- Max clearance
- 0.074 mm
- Min clearance
- 0.020 mm
- Mean
- +0.047 mm
Fit diagram (µm · zero line = nominal)
Hole tolerance zoneShaft tolerance zoneClearance
About F8/h7
Shaft-basis equivalent of H8/f7 for bearings on a plain shaft.
At Ø25 mm the hole F8 measures +0.020 mm to +0.053 mm and the shaft h7 −0.021 mm to 0 mm, giving a clearance of 0.020 mm to 0.074 mm.
How the limits are calculated
Hole F8: fundamental deviation ES/EI per ISO 286-1 Table 2, standard tolerance IT8 = 33 µm for 18–30 mm. Shaft h7: fundamental deviation es = 0, IT7 = 21 µm. Clearance = hole − shaft, evaluated at both extremes. Values per ISO 286-1:2010.
F8/h7 limits by size range
| Size (mm) | Hole F8 | Shaft h7 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.020 / +0.006 | 0 / −0.010 | +0.006 | +0.030 |
| 3 – 6 | +0.028 / +0.010 | 0 / −0.012 | +0.010 | +0.040 |
| 6 – 10 | +0.035 / +0.013 | 0 / −0.015 | +0.013 | +0.050 |
| 10 – 18 | +0.043 / +0.016 | 0 / −0.018 | +0.016 | +0.061 |
| 18 – 30 | +0.053 / +0.020 | 0 / −0.021 | +0.020 | +0.074 |
| 30 – 50 | +0.064 / +0.025 | 0 / −0.025 | +0.025 | +0.089 |
| 50 – 80 | +0.076 / +0.030 | 0 / −0.030 | +0.030 | +0.106 |
| 80 – 120 | +0.090 / +0.036 | 0 / −0.035 | +0.036 | +0.125 |
| 120 – 180 | +0.106 / +0.043 | 0 / −0.040 | +0.043 | +0.146 |
| 180 – 250 | +0.122 / +0.050 | 0 / −0.046 | +0.050 | +0.168 |
| 250 – 315 | +0.137 / +0.056 | 0 / −0.052 | +0.056 | +0.189 |
| 315 – 400 | +0.151 / +0.062 | 0 / −0.057 | +0.062 | +0.208 |
| 400 – 500 | +0.165 / +0.068 | 0 / −0.063 | +0.068 | +0.228 |
Deviations in mm at the upper end of each range; negative clearance = interference. Clearance columns are shown on wider screens. Sub-ranges (e.g. 18–24 / 24–30) can differ for r, s, t, u, v, x, y, z — use the calculator for the exact size.