Tolerance chart
f7 tolerance (shaft): ISO 286 chart up to 500 mm
f7 is an ISO tolerance class for shafts (external features) under ISO 286. At Ø25 mm it means −20 / −41 µm: the size may lie between 24.959 and 24.980 mm. Below are the deviations for every nominal size up to 500 mm and the fits that use f7.
f7 chart: deviations for all nominal sizes up to 500 mm
Deviations in µm (1 µm = 0.001 mm). A nominal size belongs to the row »over … up to and including …«: exactly 30 mm is in the row ending at 30, 30.1 mm in the next one.
| Nominal size over – to (mm) | Upper deviation | Lower deviation | Tolerance |
|---|---|---|---|
| 0 – 3 | −6 | −16 | 10 |
| 3 – 6 | −10 | −22 | 12 |
| 6 – 10 | −13 | −28 | 15 |
| 10 – 18 | −16 | −34 | 18 |
| 18 – 30 | −20 | −41 | 21 |
| 30 – 50 | −25 | −50 | 25 |
| 50 – 80 | −30 | −60 | 30 |
| 80 – 120 | −36 | −71 | 35 |
| 120 – 180 | −43 | −83 | 40 |
| 180 – 250 | −50 | −96 | 46 |
| 250 – 315 | −56 | −108 | 52 |
| 315 – 400 | −62 | −119 | 57 |
| 400 – 500 | −68 | −131 | 63 |
f7 for your nominal size
How f7 is built
An ISO tolerance class is a letter and a number. Capital letters stand for holes, small letters for shafts. The letter f sets the position of the tolerance zone; at Ø25 mm it lies entirely below the nominal size: the shaft is always smaller than nominal. The number 7 is the standard tolerance grade IT7: it sets how wide the zone is – 21 µm at Ø25 mm.
The tolerance grows with the nominal size: 10 µm in the smallest row (0 – 3 mm), 63 µm in the largest (400 – 500 mm). On a drawing the class follows the dimension, as in »Ø25 f7«; the inspection plan turns that into the limits 24.959 and 24.980 mm.
Fits with f7 at Ø25 mm
Hole-basis system: the hole is H, the shaft f7. Clearance in µm; a minus means interference. Sorted from the largest minimum clearance to the largest interference.
Frequently asked questions about f7
What does f7 mean?
f7 is an ISO tolerance class for shafts (external features): the letter f sets the position of the tolerance zone, the number 7 the standard tolerance grade IT7. At Ø25 mm that gives −20 / −41 µm, i.e. 24.959 to 24.980 mm.
What are the f7 limits at Ø10 and Ø50 mm?
Ø10 f7: −13 / −28 µm (9.972 to 9.987 mm). Ø50 f7: −25 / −50 µm (49.950 to 49.975 mm).
Is f7 a clearance fit?
A tolerance class on its own is not a fit – only together with its mating part. H8/f7 at Ø25 mm is a clearance fit (maximum clearance 74 µm, minimum clearance 20 µm; a minus means interference).
More tolerance classes
Same letter f, other grades: f6
All classes at a glance: ISO 286 tolerance charts. The same chart in German: f7 Toleranz.