K7 tolerance (hole, IT7)
Hole tolerance class K7 per ISO 286-1:2010: fundamental deviation ES 0 … +18, grade IT7 (10 µm at ≤ 3 mm to 63 µm at 400–500 mm). For an exact size, open the calculator with K7 selected.
- Type
- Hole
- Grade
- IT7
- Tolerance
- 10 … 63 µm
- Fund. deviation
- ES 0 … +18 µm
K7 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | 0 | −10 | 3.000 | 2.990 | 0 | −0.010 | 0 / −0.00039 |
| 3 – 6 | +3 | −9 | 6.003 | 5.991 | +0.003 | −0.009 | +0.00012 / −0.00035 |
| 6 – 10 | +5 | −10 | 10.005 | 9.990 | +0.005 | −0.010 | +0.00020 / −0.00039 |
| 10 – 14 | +6 | −12 | 14.006 | 13.988 | +0.006 | −0.012 | +0.00024 / −0.00047 |
| 14 – 18 | +6 | −12 | 18.006 | 17.988 | +0.006 | −0.012 | +0.00024 / −0.00047 |
| 18 – 24 | +6 | −15 | 24.006 | 23.985 | +0.006 | −0.015 | +0.00024 / −0.00059 |
| 24 – 30 | +6 | −15 | 30.006 | 29.985 | +0.006 | −0.015 | +0.00024 / −0.00059 |
| 30 – 40 | +7 | −18 | 40.007 | 39.982 | +0.007 | −0.018 | +0.00028 / −0.00071 |
| 40 – 50 | +7 | −18 | 50.007 | 49.982 | +0.007 | −0.018 | +0.00028 / −0.00071 |
| 50 – 65 | +9 | −21 | 65.009 | 64.979 | +0.009 | −0.021 | +0.00035 / −0.00083 |
| 65 – 80 | +9 | −21 | 80.009 | 79.979 | +0.009 | −0.021 | +0.00035 / −0.00083 |
| 80 – 100 | +10 | −25 | 100.010 | 99.975 | +0.010 | −0.025 | +0.00039 / −0.00098 |
| 100 – 120 | +10 | −25 | 120.010 | 119.975 | +0.010 | −0.025 | +0.00039 / −0.00098 |
| 120 – 140 | +12 | −28 | 140.012 | 139.972 | +0.012 | −0.028 | +0.00047 / −0.00110 |
| 140 – 160 | +12 | −28 | 160.012 | 159.972 | +0.012 | −0.028 | +0.00047 / −0.00110 |
| 160 – 180 | +12 | −28 | 180.012 | 179.972 | +0.012 | −0.028 | +0.00047 / −0.00110 |
| 180 – 200 | +13 | −33 | 200.013 | 199.967 | +0.013 | −0.033 | +0.00051 / −0.00130 |
| 200 – 225 | +13 | −33 | 225.013 | 224.967 | +0.013 | −0.033 | +0.00051 / −0.00130 |
| 225 – 250 | +13 | −33 | 250.013 | 249.967 | +0.013 | −0.033 | +0.00051 / −0.00130 |
| 250 – 280 | +16 | −36 | 280.016 | 279.964 | +0.016 | −0.036 | +0.00063 / −0.00142 |
| 280 – 315 | +16 | −36 | 315.016 | 314.964 | +0.016 | −0.036 | +0.00063 / −0.00142 |
| 315 – 355 | +17 | −40 | 355.017 | 354.960 | +0.017 | −0.040 | +0.00067 / −0.00157 |
| 355 – 400 | +17 | −40 | 400.017 | 399.960 | +0.017 | −0.040 | +0.00067 / −0.00157 |
| 400 – 450 | +18 | −45 | 450.018 | 449.955 | +0.018 | −0.045 | +0.00071 / −0.00177 |
| 450 – 500 | +18 | −45 | 500.018 | 499.955 | +0.018 | −0.045 | +0.00071 / −0.00177 |
Deviations at the upper end of each range (Ø columns use that size); use the calculator for the exact size. — : not defined by ISO 286 for that size. Upper/Lower (mm) and inch columns are shown on wider screens.
About K7
K7 denotes a hole tolerance zone with transition deviation in the ISO 286 system. It is used in K7/h6 (Shaft-basis equivalent of H7/k6, e.g. ball-bearing outer rings in housings.).
At Ø25 mm K7 is +0.006 / −0.015 mm, i.e. 24.985 to 25.006 mm.
How the limits are calculated
K7 uses grade IT7 (a standard tolerance of 21 µm at 18–30 mm). Fundamental deviation: ES = −ei + Δ (Δ = ITn − IT(n−1), applied up to IT8 for K/M/N and IT7 otherwise); IT7 sets the width below ES. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.