U7/h6 fit — Force fit (shaft basis)

ISO 286 shaft-basis interference fit. Enter a nominal size to get the limits.

Nominal size

Unit

Result

Ø25.000 U7/h6Interference fit

	Upper	Lower	Max	Min	Tol.
Hole U7	−0.040	−0.061	24.960	24.939	0.021
Shaft h6	0	−0.013	25.000	24.987	0.013

Max interference: 0.061 mm
Min interference: 0.027 mm
Mean: −0.044 mm

Fit diagram (µm · zero line = nominal)

Hole tolerance zoneShaft tolerance zoneInterference

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. 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.