H8/s7 fit — Drive fit
ISO 286 hole-basis interference fit. Enter a nominal size to get the limits.
About H8/s7
Coarser permanent press fit for general machinery. See press fit tolerance for interference by size across the p6–u6 family.
At Ø25 mm the hole H8 measures 0 mm to +0.033 mm and the shaft s7 +0.035 mm to +0.056 mm, giving an interference of 0.002 mm to 0.056 mm.
How the limits are calculated
Hole H8: fundamental deviation EI = 0, standard tolerance IT8 = 33 µm for 18–30 mm. Shaft s7: fundamental deviation ei = 35 µm, IT7 = 21 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
H8/s7 limits by size range
| Size (mm) | Hole H8 | Shaft s7 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.014 / 0 | +0.024 / +0.014 | −0.024 | 0 |
| 3 – 6 | +0.018 / 0 | +0.031 / +0.019 | −0.031 | −0.001 |
| 6 – 10 | +0.022 / 0 | +0.038 / +0.023 | −0.038 | −0.001 |
| 10 – 18 | +0.027 / 0 | +0.046 / +0.028 | −0.046 | −0.001 |
| 18 – 30 | +0.033 / 0 | +0.056 / +0.035 | −0.056 | −0.002 |
| 30 – 50 | +0.039 / 0 | +0.068 / +0.043 | −0.068 | −0.004 |
| 50 – 80 | +0.046 / 0 | +0.089 / +0.059 | −0.089 | −0.013 |
| 80 – 120 | +0.054 / 0 | +0.114 / +0.079 | −0.114 | −0.025 |
| 120 – 180 | +0.063 / 0 | +0.148 / +0.108 | −0.148 | −0.045 |
| 180 – 250 | +0.072 / 0 | +0.186 / +0.140 | −0.186 | −0.068 |
| 250 – 315 | +0.081 / 0 | +0.222 / +0.170 | −0.222 | −0.089 |
| 315 – 400 | +0.089 / 0 | +0.265 / +0.208 | −0.265 | −0.119 |
| 400 – 500 | +0.097 / 0 | +0.315 / +0.252 | −0.315 | −0.155 |
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. “—” means ISO 286 doesn't define this class below that size (e.g. t only starts at 24 mm).
Is H8/s7 a clearance fit?
No — H8/s7 is an interference fit per ISO 286 (see types of fits). At Ø25 mm it gives an interference of 0.002 mm to 0.056 mm mm, depending which parts of the tolerance zones are paired.
What is the H8/s7 tolerance at 25 mm?
At a nominal size of Ø25 mm, H8 allows a hole diameter from 25.000 to 25.033 mm, and s7 allows a shaft diameter from 25.035 to 25.056 mm.