N7/h6 fit — Locational transition (shaft basis)
ISO 286 shaft-basis transition fit. Enter a nominal size to get the limits.
About N7/h6
Shaft-basis equivalent of H7/n6; common for bearing outer rings under rotating outer-ring load.
At Ø25 mm the hole N7 measures −0.028 mm to −0.007 mm and the shaft h6 −0.013 mm to 0 mm, giving between 0.028 mm interference and 0.006 mm clearance.
How the limits are calculated
Hole N7: fundamental deviation ES/EI per ISO 286-1 Table 2, standard tolerance IT7 = 21 µm for 18–30 mm. Shaft h6: fundamental deviation es = 0, IT6 = 13 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
N7/h6 limits by size range
| Size (mm) | Hole N7 | Shaft h6 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | −0.004 / −0.014 | 0 / −0.006 | −0.014 | +0.002 |
| 3 – 6 | −0.004 / −0.016 | 0 / −0.008 | −0.016 | +0.004 |
| 6 – 10 | −0.004 / −0.019 | 0 / −0.009 | −0.019 | +0.005 |
| 10 – 18 | −0.005 / −0.023 | 0 / −0.011 | −0.023 | +0.006 |
| 18 – 30 | −0.007 / −0.028 | 0 / −0.013 | −0.028 | +0.006 |
| 30 – 50 | −0.008 / −0.033 | 0 / −0.016 | −0.033 | +0.008 |
| 50 – 80 | −0.009 / −0.039 | 0 / −0.019 | −0.039 | +0.010 |
| 80 – 120 | −0.010 / −0.045 | 0 / −0.022 | −0.045 | +0.012 |
| 120 – 180 | −0.012 / −0.052 | 0 / −0.025 | −0.052 | +0.013 |
| 180 – 250 | −0.014 / −0.060 | 0 / −0.029 | −0.060 | +0.015 |
| 250 – 315 | −0.014 / −0.066 | 0 / −0.032 | −0.066 | +0.018 |
| 315 – 400 | −0.016 / −0.073 | 0 / −0.036 | −0.073 | +0.020 |
| 400 – 500 | −0.017 / −0.080 | 0 / −0.040 | −0.080 | +0.023 |
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 N7/h6 a clearance fit?
Not always — N7/h6 is a transition fit per ISO 286 (see types of fits). At Ø25 mm it gives between 0.028 mm mm interference and 0.006 mm mm clearance, depending which parts of the tolerance zones are paired.
What is the N7/h6 tolerance at 25 mm?
At a nominal size of Ø25 mm, N7 allows a hole diameter from 24.972 to 24.993 mm, and h6 allows a shaft diameter from 24.987 to 25.000 mm.