N6/h5 fit — Precision interference (shaft basis)
ISO 286 shaft-basis interference fit. Enter a nominal size to get the limits.
About N6/h5
Shaft-basis equivalent of H6/n5, for precision parts that must stay fixed on a shared ground shaft without a key.
At Ø25 mm the hole N6 measures −0.024 mm to −0.011 mm and the shaft h5 −0.009 mm to 0 mm, giving an interference of 0.002 mm to 0.024 mm.
How the limits are calculated
Hole N6: fundamental deviation ES/EI per ISO 286-1 Table 2, standard tolerance IT6 = 13 µm for 18–30 mm. Shaft h5: fundamental deviation es = 0, IT5 = 9 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
N6/h5 limits by size range
| Size (mm) | Hole N6 | Shaft h5 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | −0.004 / −0.010 | 0 / −0.004 | −0.010 | 0 |
| 3 – 6 | −0.005 / −0.013 | 0 / −0.005 | −0.013 | 0 |
| 6 – 10 | −0.007 / −0.016 | 0 / −0.006 | −0.016 | −0.001 |
| 10 – 18 | −0.009 / −0.020 | 0 / −0.008 | −0.020 | −0.001 |
| 18 – 30 | −0.011 / −0.024 | 0 / −0.009 | −0.024 | −0.002 |
| 30 – 50 | −0.012 / −0.028 | 0 / −0.011 | −0.028 | −0.001 |
| 50 – 80 | −0.014 / −0.033 | 0 / −0.013 | −0.033 | −0.001 |
| 80 – 120 | −0.016 / −0.038 | 0 / −0.015 | −0.038 | −0.001 |
| 120 – 180 | −0.020 / −0.045 | 0 / −0.018 | −0.045 | −0.002 |
| 180 – 250 | −0.022 / −0.051 | 0 / −0.020 | −0.051 | −0.002 |
| 250 – 315 | −0.025 / −0.057 | 0 / −0.023 | −0.057 | −0.002 |
| 315 – 400 | −0.026 / −0.062 | 0 / −0.025 | −0.062 | −0.001 |
| 400 – 500 | −0.027 / −0.067 | 0 / −0.027 | −0.067 | 0 |
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 N6/h5 a clearance fit?
No — N6/h5 is an interference fit per ISO 286 (see types of fits). At Ø25 mm it gives an interference of 0.002 mm to 0.024 mm mm, depending which parts of the tolerance zones are paired.
What is the N6/h5 tolerance at 25 mm?
At a nominal size of Ø25 mm, N6 allows a hole diameter from 24.976 to 24.989 mm, and h5 allows a shaft diameter from 24.991 to 25.000 mm.