H7/k6 fit — Locational transition

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

Nominal size

Unit

Result

Ø25.000 H7/k6Transition fit

	Upper	Lower	Max	Min	Tol.
Hole H7	+0.021	0	25.021	25.000	0.021
Shaft k6	+0.015	+0.002	25.015	25.002	0.013

Max clearance: 0.019 mm
Max interference: 0.015 mm
Mean: +0.002 mm

Fit diagram (µm · zero line = nominal)

Hole tolerance zoneShaft tolerance zoneClearanceInterference

About H7/k6

The standard "push fit" for gears, pulleys and ball-bearing inner rings on shafts; assembles with a light press or mallet, transmits torque only with a key.

At Ø25 mm the hole H7 measures 0 mm to +0.021 mm and the shaft k6 +0.002 mm to +0.015 mm, giving between 0.015 mm interference and 0.019 mm clearance.

How the limits are calculated

Hole H7: fundamental deviation EI = 0, standard tolerance IT7 = 21 µm for 18–30 mm. Shaft k6: fundamental deviation ei = 2 µm, IT6 = 13 µm. Clearance = hole − shaft, evaluated at both extremes. Values per ISO 286-1:2010.

H7/k6 limits by size range

Size (mm)	Hole H7	Shaft k6	Clearance min	Clearance max
≤ 3	+0.010 / 0	+0.006 / 0	−0.006	+0.010
3 – 6	+0.012 / 0	+0.009 / +0.001	−0.009	+0.011
6 – 10	+0.015 / 0	+0.010 / +0.001	−0.010	+0.014
10 – 18	+0.018 / 0	+0.012 / +0.001	−0.012	+0.017
18 – 30	+0.021 / 0	+0.015 / +0.002	−0.015	+0.019
30 – 50	+0.025 / 0	+0.018 / +0.002	−0.018	+0.023
50 – 80	+0.030 / 0	+0.021 / +0.002	−0.021	+0.028
80 – 120	+0.035 / 0	+0.025 / +0.003	−0.025	+0.032
120 – 180	+0.040 / 0	+0.028 / +0.003	−0.028	+0.037
180 – 250	+0.046 / 0	+0.033 / +0.004	−0.033	+0.042
250 – 315	+0.052 / 0	+0.036 / +0.004	−0.036	+0.048
315 – 400	+0.057 / 0	+0.040 / +0.004	−0.040	+0.053
400 – 500	+0.063 / 0	+0.045 / +0.005	−0.045	+0.058

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.