H6/f6 fit — Precision running fit
ISO 286 hole-basis clearance fit. Enter a nominal size to get the limits.
About H6/f6
High-precision running clearance for ground shafts in instrument and machine-tool plain bearings where H7/f7-class play is too loose: spindle bearings, precision slides.
At Ø25 mm the hole H6 measures 0 mm to +0.013 mm and the shaft f6 −0.033 mm to −0.020 mm, giving a clearance of 0.020 mm to 0.046 mm.
How the limits are calculated
Hole H6: fundamental deviation EI = 0, standard tolerance IT6 = 13 µm for 18–30 mm. Shaft f6: fundamental deviation es = -20 µm, IT6 = 13 µm. Clearance = hole − shaft, evaluated at both extremes. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
H6/f6 limits by size range
| Size (mm) | Hole H6 | Shaft f6 | Clearance min | Clearance max |
|---|---|---|---|---|
| ≤ 3 | +0.006 / 0 | −0.006 / −0.012 | +0.006 | +0.018 |
| 3 – 6 | +0.008 / 0 | −0.010 / −0.018 | +0.010 | +0.026 |
| 6 – 10 | +0.009 / 0 | −0.013 / −0.022 | +0.013 | +0.031 |
| 10 – 18 | +0.011 / 0 | −0.016 / −0.027 | +0.016 | +0.038 |
| 18 – 30 | +0.013 / 0 | −0.020 / −0.033 | +0.020 | +0.046 |
| 30 – 50 | +0.016 / 0 | −0.025 / −0.041 | +0.025 | +0.057 |
| 50 – 80 | +0.019 / 0 | −0.030 / −0.049 | +0.030 | +0.068 |
| 80 – 120 | +0.022 / 0 | −0.036 / −0.058 | +0.036 | +0.080 |
| 120 – 180 | +0.025 / 0 | −0.043 / −0.068 | +0.043 | +0.093 |
| 180 – 250 | +0.029 / 0 | −0.050 / −0.079 | +0.050 | +0.108 |
| 250 – 315 | +0.032 / 0 | −0.056 / −0.088 | +0.056 | +0.120 |
| 315 – 400 | +0.036 / 0 | −0.062 / −0.098 | +0.062 | +0.134 |
| 400 – 500 | +0.040 / 0 | −0.068 / −0.108 | +0.068 | +0.148 |
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 H6/f6 a clearance fit?
Yes — H6/f6 is a clearance fit per ISO 286 (see types of fits). At Ø25 mm it gives a clearance of 0.020 mm to 0.046 mm mm, depending which parts of the tolerance zones are paired.
What is the H6/f6 tolerance at 25 mm?
At a nominal size of Ø25 mm, H6 allows a hole diameter from 25.000 to 25.013 mm, and f6 allows a shaft diameter from 24.967 to 24.980 mm.