H8/s7 fit — Drive fit

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

Nominal size

Unit

Result

Ø25.000 H8/s7Interference fit

	Upper	Lower	Max	Min	Tol.
Hole H8	+0.033	0	25.033	25.000	0.033
Shaft s7	+0.056	+0.035	25.056	25.035	0.021

Max interference: 0.056 mm
Min interference: 0.002 mm
Mean: −0.029 mm

Fit diagram (µm · zero line = nominal)

Hole tolerance zoneShaft tolerance zoneInterference

About H8/s7

Coarser permanent press fit for general machinery.

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. 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.