U7/h6 fit — Force fit (shaft basis)
ISO 286 shaft-basis interference fit. Enter a nominal size to get the limits.
About U7/h6
Shaft-basis equivalent of H7/u6.
At Ø25 mm the hole U7 measures −0.061 mm to −0.040 mm and the shaft h6 −0.013 mm to 0 mm, giving an interference of 0.027 mm to 0.061 mm.
How the limits are calculated
Hole U7: 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.
U7/h6 limits by size range
| Size (mm) | Hole U7 | Shaft h6 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | −0.018 / −0.028 | 0 / −0.006 | −0.028 | −0.012 |
| 3 – 6 | −0.019 / −0.031 | 0 / −0.008 | −0.031 | −0.011 |
| 6 – 10 | −0.022 / −0.037 | 0 / −0.009 | −0.037 | −0.013 |
| 10 – 18 | −0.026 / −0.044 | 0 / −0.011 | −0.044 | −0.015 |
| 18 – 30 | −0.040 / −0.061 | 0 / −0.013 | −0.061 | −0.027 |
| 30 – 50 | −0.061 / −0.086 | 0 / −0.016 | −0.086 | −0.045 |
| 50 – 80 | −0.091 / −0.121 | 0 / −0.019 | −0.121 | −0.072 |
| 80 – 120 | −0.131 / −0.166 | 0 / −0.022 | −0.166 | −0.109 |
| 120 – 180 | −0.195 / −0.235 | 0 / −0.025 | −0.235 | −0.170 |
| 180 – 250 | −0.267 / −0.313 | 0 / −0.029 | −0.313 | −0.238 |
| 250 – 315 | −0.330 / −0.382 | 0 / −0.032 | −0.382 | −0.298 |
| 315 – 400 | −0.414 / −0.471 | 0 / −0.036 | −0.471 | −0.378 |
| 400 – 500 | −0.517 / −0.580 | 0 / −0.040 | −0.580 | −0.477 |
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 U7/h6 a clearance fit?
No — U7/h6 is an interference fit per ISO 286 (see types of fits). At Ø25 mm it gives an interference of 0.027 mm to 0.061 mm mm, depending which parts of the tolerance zones are paired.
What is the U7/h6 tolerance at 25 mm?
At a nominal size of Ø25 mm, U7 allows a hole diameter from 24.939 to 24.960 mm, and h6 allows a shaft diameter from 24.987 to 25.000 mm.