j6 shaft tolerance (IT6)
Lower-case j6 is an ISO 286 shaft tolerance class (IT6, ei −2 … −20 µm): at Ø10 mm the deviations are +0.007/−0.002 mm, at Ø25 mm +0.009/−0.004 mm (upper/lower).
Shaft tolerance class j6 per ISO 286-1:2010: fundamental deviation ei −2 … −20, grade IT6 (6 µm at ≤ 3 mm to 40 µm at 400–500 mm). For an exact size, open the calculator with j6 selected.
- Type
- Shaft
- Grade
- IT6
- Tolerance
- 6 … 40 µm
- Fund. deviation
- ei −2 … −20 µm
j6 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +4 | −2 | 3.004 | 2.998 | +0.004 | −0.002 | +0.00016 / −0.00008 |
| 3 – 6 | +6 | −2 | 6.006 | 5.998 | +0.006 | −0.002 | +0.00024 / −0.00008 |
| 6 – 10 | +7 | −2 | 10.007 | 9.998 | +0.007 | −0.002 | +0.00028 / −0.00008 |
| 10 – 14 | +8 | −3 | 14.008 | 13.997 | +0.008 | −0.003 | +0.00031 / −0.00012 |
| 14 – 18 | +8 | −3 | 18.008 | 17.997 | +0.008 | −0.003 | +0.00031 / −0.00012 |
| 18 – 24 | +9 | −4 | 24.009 | 23.996 | +0.009 | −0.004 | +0.00035 / −0.00016 |
| 24 – 30 | +9 | −4 | 30.009 | 29.996 | +0.009 | −0.004 | +0.00035 / −0.00016 |
| 30 – 40 | +11 | −5 | 40.011 | 39.995 | +0.011 | −0.005 | +0.00043 / −0.00020 |
| 40 – 50 | +11 | −5 | 50.011 | 49.995 | +0.011 | −0.005 | +0.00043 / −0.00020 |
| 50 – 65 | +12 | −7 | 65.012 | 64.993 | +0.012 | −0.007 | +0.00047 / −0.00028 |
| 65 – 80 | +12 | −7 | 80.012 | 79.993 | +0.012 | −0.007 | +0.00047 / −0.00028 |
| 80 – 100 | +13 | −9 | 100.013 | 99.991 | +0.013 | −0.009 | +0.00051 / −0.00035 |
| 100 – 120 | +13 | −9 | 120.013 | 119.991 | +0.013 | −0.009 | +0.00051 / −0.00035 |
| 120 – 140 | +14 | −11 | 140.014 | 139.989 | +0.014 | −0.011 | +0.00055 / −0.00043 |
| 140 – 160 | +14 | −11 | 160.014 | 159.989 | +0.014 | −0.011 | +0.00055 / −0.00043 |
| 160 – 180 | +14 | −11 | 180.014 | 179.989 | +0.014 | −0.011 | +0.00055 / −0.00043 |
| 180 – 200 | +16 | −13 | 200.016 | 199.987 | +0.016 | −0.013 | +0.00063 / −0.00051 |
| 200 – 225 | +16 | −13 | 225.016 | 224.987 | +0.016 | −0.013 | +0.00063 / −0.00051 |
| 225 – 250 | +16 | −13 | 250.016 | 249.987 | +0.016 | −0.013 | +0.00063 / −0.00051 |
| 250 – 280 | +16 | −16 | 280.016 | 279.984 | +0.016 | −0.016 | +0.00063 / −0.00063 |
| 280 – 315 | +16 | −16 | 315.016 | 314.984 | +0.016 | −0.016 | +0.00063 / −0.00063 |
| 315 – 355 | +18 | −18 | 355.018 | 354.982 | +0.018 | −0.018 | +0.00071 / −0.00071 |
| 355 – 400 | +18 | −18 | 400.018 | 399.982 | +0.018 | −0.018 | +0.00071 / −0.00071 |
| 400 – 450 | +20 | −20 | 450.020 | 449.980 | +0.020 | −0.020 | +0.00079 / −0.00079 |
| 450 – 500 | +20 | −20 | 500.020 | 499.980 | +0.020 | −0.020 | +0.00079 / −0.00079 |
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 j6
j6 denotes a shaft tolerance zone with transition deviation in the ISO 286 system. It is used in H7/j6 (A lighter transition than js6/k6, still seen on older (pre-ISO 286) drawings for ball-bearing inner rings under light, steady load; locates the part but allows hand assembly with only an occasional tap.).
At Ø25 mm j6 is +0.009 / −0.004 mm, i.e. 24.996 to 25.009 mm.
How the limits are calculated
j6 uses grade IT6 (a standard tolerance of 13 µm at 18–30 mm). Fundamental deviation: ei is tabulated directly by ISO 286-1 Table 2; es = ei + IT6. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.
j6 in practice
Where it's used
j6 is a light transition shaft: its zone straddles the nominal size, reaching further above it than below. Its main use is bearing seats under light, steady load, where the inner ring should sit firmly but go on by hand or with a light tap. It also appears on older drawings for hubs that must locate without a press. ISO 286 defines j for only a few grades, and newer designs often use js6, k5 or k6 instead.
How to check it
Because the zone crosses the nominal size, both limits matter: snap gauge GO at the upper limit, NO-GO at the lower. On a bearing seat, record the actual size with a micrometer rather than just pass/fail, because the resulting fit depends on where in the band the shaft lands. Check roundness too: an oval seat distorts a thin inner ring.
Easily confused with
js6 is the symmetric class (±IT6/2); j6 is asymmetric and sits slightly higher. J6 in capitals is the hole class. And a rolling-bearing bore is not an H hole: ISO 492 tolerances it entirely below the nominal size, so a j6 seat is tighter in service than the textbook H7/j6 suggests.
Worked example
A 6205 ball bearing has a 25 mm bore toleranced 0/−10 µm (ISO 492, Normal class). On a Ø25 j6 seat (24.996–25.009 mm, +0.009/−0.004 mm) the fit runs from 0.004 mm clearance to 0.019 mm interference, mostly a light press fit.