Tolerance chart
n5 tolerance (shaft): ISO 286 chart up to 500 mm
n5 is an ISO tolerance class for shafts (external features) under ISO 286. At Ø25 mm it means +24 / +15 µm: the size may lie between 25.015 and 25.024 mm. Below are the deviations for every nominal size up to 500 mm and the fits that use n5.
n5 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 | +8 | +4 | 4 |
| 3 – 6 | +13 | +8 | 5 |
| 6 – 10 | +16 | +10 | 6 |
| 10 – 18 | +20 | +12 | 8 |
| 18 – 30 | +24 | +15 | 9 |
| 30 – 50 | +28 | +17 | 11 |
| 50 – 80 | +33 | +20 | 13 |
| 80 – 120 | +38 | +23 | 15 |
| 120 – 180 | +45 | +27 | 18 |
| 180 – 250 | +51 | +31 | 20 |
| 250 – 315 | +57 | +34 | 23 |
| 315 – 400 | +62 | +37 | 25 |
| 400 – 500 | +67 | +40 | 27 |
n5 for your nominal size
How n5 is built
An ISO tolerance class is a letter and a number. Capital letters stand for holes, small letters for shafts. The letter n sets the position of the tolerance zone; at Ø25 mm it lies entirely above the nominal size: the shaft is always larger than nominal. The number 5 is the standard tolerance grade IT5: it sets how wide the zone is – 9 µm at Ø25 mm.
The tolerance grows with the nominal size: 4 µm in the smallest row (0 – 3 mm), 27 µm in the largest (400 – 500 mm). On a drawing the class follows the dimension, as in »Ø25 n5«; the inspection plan turns that into the limits 25.015 and 25.024 mm.
Fits with n5 at Ø25 mm
Hole-basis system: the hole is H, the shaft n5. Clearance in µm; a minus means interference. Sorted from the largest minimum clearance to the largest interference.
| Fit | Type | Max. clearance | Min. clearance |
|---|---|---|---|
| H6/n5 | interference fit | −2 | −24 |
Frequently asked questions about n5
What does n5 mean?
n5 is an ISO tolerance class for shafts (external features): the letter n sets the position of the tolerance zone, the number 5 the standard tolerance grade IT5. At Ø25 mm that gives +24 / +15 µm, i.e. 25.015 to 25.024 mm.
What are the n5 limits at Ø10 and Ø50 mm?
Ø10 n5: +16 / +10 µm (10.010 to 10.016 mm). Ø50 n5: +28 / +17 µm (50.017 to 50.028 mm).
Is n5 a clearance fit?
A tolerance class on its own is not a fit – only together with its mating part. H6/n5 at Ø25 mm is a interference fit (maximum clearance −2 µm, minimum clearance −24 µm; a minus means interference).
More tolerance classes
Same letter n, other grades: n6
Shafts in grade 5: h5 · g5 · js5 · k5 · m5
All classes at a glance: ISO 286 tolerance charts. The same chart in German: n5 Toleranz.