H8/g7 fit — Sliding fit
ISO 286 hole-basis clearance fit. Enter a nominal size to get the limits.
About H8/g7
Coarser than H7/g6 for guide pins, sliding sleeves and levers needing smooth, near-zero-play motion but made on general-purpose (not precision) machine tools.
At Ø25 mm the hole H8 measures 0 mm to +0.033 mm and the shaft g7 −0.028 mm to −0.007 mm, giving a clearance of 0.007 mm to 0.061 mm.
How the limits are calculated
Hole H8: fundamental deviation EI = 0, standard tolerance IT8 = 33 µm for 18–30 mm. Shaft g7: fundamental deviation es = -7 µm, IT7 = 21 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
H8/g7 limits by size range
| Size (mm) | Hole H8 | Shaft g7 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.014 / 0 | −0.002 / −0.012 | +0.002 | +0.026 |
| 3 – 6 | +0.018 / 0 | −0.004 / −0.016 | +0.004 | +0.034 |
| 6 – 10 | +0.022 / 0 | −0.005 / −0.020 | +0.005 | +0.042 |
| 10 – 18 | +0.027 / 0 | −0.006 / −0.024 | +0.006 | +0.051 |
| 18 – 30 | +0.033 / 0 | −0.007 / −0.028 | +0.007 | +0.061 |
| 30 – 50 | +0.039 / 0 | −0.009 / −0.034 | +0.009 | +0.073 |
| 50 – 80 | +0.046 / 0 | −0.010 / −0.040 | +0.010 | +0.086 |
| 80 – 120 | +0.054 / 0 | −0.012 / −0.047 | +0.012 | +0.101 |
| 120 – 180 | +0.063 / 0 | −0.014 / −0.054 | +0.014 | +0.117 |
| 180 – 250 | +0.072 / 0 | −0.015 / −0.061 | +0.015 | +0.133 |
| 250 – 315 | +0.081 / 0 | −0.017 / −0.069 | +0.017 | +0.150 |
| 315 – 400 | +0.089 / 0 | −0.018 / −0.075 | +0.018 | +0.164 |
| 400 – 500 | +0.097 / 0 | −0.020 / −0.083 | +0.020 | +0.180 |
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 H8/g7 a clearance fit?
Yes — H8/g7 is a clearance fit per ISO 286 (see types of fits). At Ø25 mm it gives a clearance of 0.007 mm to 0.061 mm mm, depending which parts of the tolerance zones are paired.
What is the H8/g7 tolerance at 25 mm?
At a nominal size of Ø25 mm, H8 allows a hole diameter from 25.000 to 25.033 mm, and g7 allows a shaft diameter from 24.972 to 24.993 mm.