JS8 tolerance (hole, IT8)
Hole tolerance class JS8 per ISO 286-1:2010: fundamental deviation ±IT/2, grade IT8 (14 µm at ≤ 3 mm to 97 µm at 400–500 mm). For an exact size, open the calculator with JS8 selected.
- Type
- Hole
- Grade
- IT8
- Tolerance
- 14 … 97 µm
- Fund. deviation
- ±IT/2
JS8 limits by size range
| Size (mm) | Upper (µm) | Lower (µm) | Ø max (mm) | Ø min (mm) | Upper (mm) | Lower (mm) | Dev. (in) |
|---|---|---|---|---|---|---|---|
| ≤ 3 | +7 | −7 | 3.007 | 2.993 | +0.0070 | −0.0070 | +0.00028 / −0.00028 |
| 3 – 6 | +9 | −9 | 6.009 | 5.991 | +0.0090 | −0.0090 | +0.00035 / −0.00035 |
| 6 – 10 | +11 | −11 | 10.011 | 9.989 | +0.0110 | −0.0110 | +0.00043 / −0.00043 |
| 10 – 14 | +13.5 | −13.5 | 14.0135 | 13.9865 | +0.0135 | −0.0135 | +0.00053 / −0.00053 |
| 14 – 18 | +13.5 | −13.5 | 18.0135 | 17.9865 | +0.0135 | −0.0135 | +0.00053 / −0.00053 |
| 18 – 24 | +16.5 | −16.5 | 24.0165 | 23.9835 | +0.0165 | −0.0165 | +0.00065 / −0.00065 |
| 24 – 30 | +16.5 | −16.5 | 30.0165 | 29.9835 | +0.0165 | −0.0165 | +0.00065 / −0.00065 |
| 30 – 40 | +19.5 | −19.5 | 40.0195 | 39.9805 | +0.0195 | −0.0195 | +0.00077 / −0.00077 |
| 40 – 50 | +19.5 | −19.5 | 50.0195 | 49.9805 | +0.0195 | −0.0195 | +0.00077 / −0.00077 |
| 50 – 65 | +23 | −23 | 65.023 | 64.977 | +0.0230 | −0.0230 | +0.00091 / −0.00091 |
| 65 – 80 | +23 | −23 | 80.023 | 79.977 | +0.0230 | −0.0230 | +0.00091 / −0.00091 |
| 80 – 100 | +27 | −27 | 100.027 | 99.973 | +0.0270 | −0.0270 | +0.00106 / −0.00106 |
| 100 – 120 | +27 | −27 | 120.027 | 119.973 | +0.0270 | −0.0270 | +0.00106 / −0.00106 |
| 120 – 140 | +31.5 | −31.5 | 140.0315 | 139.9685 | +0.0315 | −0.0315 | +0.00124 / −0.00124 |
| 140 – 160 | +31.5 | −31.5 | 160.0315 | 159.9685 | +0.0315 | −0.0315 | +0.00124 / −0.00124 |
| 160 – 180 | +31.5 | −31.5 | 180.0315 | 179.9685 | +0.0315 | −0.0315 | +0.00124 / −0.00124 |
| 180 – 200 | +36 | −36 | 200.036 | 199.964 | +0.0360 | −0.0360 | +0.00142 / −0.00142 |
| 200 – 225 | +36 | −36 | 225.036 | 224.964 | +0.0360 | −0.0360 | +0.00142 / −0.00142 |
| 225 – 250 | +36 | −36 | 250.036 | 249.964 | +0.0360 | −0.0360 | +0.00142 / −0.00142 |
| 250 – 280 | +40.5 | −40.5 | 280.0405 | 279.9595 | +0.0405 | −0.0405 | +0.00159 / −0.00159 |
| 280 – 315 | +40.5 | −40.5 | 315.0405 | 314.9595 | +0.0405 | −0.0405 | +0.00159 / −0.00159 |
| 315 – 355 | +44.5 | −44.5 | 355.0445 | 354.9555 | +0.0445 | −0.0445 | +0.00175 / −0.00175 |
| 355 – 400 | +44.5 | −44.5 | 400.0445 | 399.9555 | +0.0445 | −0.0445 | +0.00175 / −0.00175 |
| 400 – 450 | +48.5 | −48.5 | 450.0485 | 449.9515 | +0.0485 | −0.0485 | +0.00191 / −0.00191 |
| 450 – 500 | +48.5 | −48.5 | 500.0485 | 499.9515 | +0.0485 | −0.0485 | +0.00191 / −0.00191 |
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 JS8
JS8 denotes a hole tolerance zone with symmetric ±IT/2 deviation in the ISO 286 system.
At Ø25 mm JS8 is +0.0165 / −0.0165 mm, i.e. 24.9835 to 25.0165 mm.
How the limits are calculated
JS8 uses grade IT8 (a standard tolerance of 33 µm at 18–30 mm). Fundamental deviation: ±IT8/2: the tolerance zone is centred on the nominal size. See the fundamental deviation table for every letter. Values per ISO 286-1:2010.