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n6 Tolerance Chart (Shaft n6)

Upper and lower deviations of shaft n6 for nominal sizes 0–500 mm, per ISO 286-1. Values in mm; "+" means larger than nominal, "-" smaller. Calculate other sizes →

Nominal size (mm)Upper deviationLower deviationTolerance (IT)
0 ~ 3+0.010+0.0040.006
>3 ~ 6+0.016+0.0080.008
>6 ~ 10+0.019+0.0100.009
>10 ~ 18+0.023+0.0120.011
>18 ~ 30+0.028+0.0150.013
>30 ~ 50+0.033+0.0170.016
>50 ~ 80+0.039+0.0200.019
>80 ~ 120+0.045+0.0230.022
>120 ~ 180+0.052+0.0270.025
>180 ~ 250+0.060+0.0310.029
>250 ~ 315+0.066+0.0340.032
>315 ~ 400+0.073+0.0370.036
>400 ~ 500+0.080+0.0400.040

Each row applies to the whole size range shown. Ranges are "over the first value, up to and including the second".

How to read n6

n6 is an ISO 286 tolerance class. The lowercase letter n is the fundamental deviation (which side of the nominal size the tolerance zone lies on), and the number 6 is the tolerance grade IT6 (how wide the zone is). Transition (tight): The tightest transition class, almost always an interference. Needs a press and is not normally dismantled: fixed pins, bushings, gear rims. Typical processes for IT6: fine grinding, fine turning, fine boring: shafts for ordinary precision fits (g6, h6, k6, m6 dowel pins).

On a drawing or in a specification, Ø6 n6 and 6(+0.016/+0.008) mean the same thing — the second form writes the deviations out, so nobody has to look them up. SFP product specifications always use the second form.

Quick lookup for common sizes

Click "Calc" in the last column to open the calculator, where the written-out form can be copied with one click.

SizeUpper deviationLower deviationActual limits (mm)
Ø1+0.010+0.0041.004 ~ 1.010Calc
Ø1.5+0.010+0.0041.504 ~ 1.510Calc
Ø2+0.010+0.0042.004 ~ 2.010Calc
Ø2.5+0.010+0.0042.504 ~ 2.510Calc
Ø3+0.010+0.0043.004 ~ 3.010Calc
Ø4+0.016+0.0084.008 ~ 4.016Calc
Ø5+0.016+0.0085.008 ~ 5.016Calc
Ø6+0.016+0.0086.008 ~ 6.016Calc
Ø8+0.019+0.0108.010 ~ 8.019Calc
Ø10+0.019+0.01010.010 ~ 10.019Calc
Ø12+0.023+0.01212.012 ~ 12.023Calc
Ø13+0.023+0.01213.012 ~ 13.023Calc
Ø16+0.023+0.01216.012 ~ 16.023Calc
Ø20+0.028+0.01520.015 ~ 20.028Calc
Ø25+0.028+0.01525.015 ~ 25.028Calc
Ø30+0.028+0.01530.015 ~ 30.028Calc
Ø35+0.033+0.01735.017 ~ 35.033Calc
Ø40+0.033+0.01740.017 ~ 40.033Calc
Ø50+0.033+0.01750.017 ~ 50.033Calc
Ø60+0.039+0.02060.020 ~ 60.039Calc
Ø80+0.039+0.02080.020 ~ 80.039Calc
Ø100+0.045+0.023100.023 ~ 100.045Calc

Common fits

FitTypeTypical use
H7/n6TransitionThe tightest transition fit, almost always an interference. Needs a press and is not normally dismantled: fixed pins, bushings, gear rims.

Alternative classes (tighter)

The tolerance zones of the classes below lie entirely inside n6 (true for every size range from 0 to 500 mm), so they also satisfy a drawing that calls for n6. Those listed first are closest to n6; price and lead time still depend on material, size and stock.

Related tolerance charts

FAQ

How big is n6 exactly?

It depends on the diameter. For Ø6, n6 means the part must measure between 6.008 and 6.016 mm, written 6(+0.016/+0.008). For other diameters see the chart above; every size range is listed.

Is n6 a shaft tolerance or a hole tolerance?

Letters in lowercase denote a shaft (outside diameter). In uppercase, N6 is a hole tolerance, lying on the opposite side of the nominal size.

The drawing calls for n6 but the parts I have are n5. Can I use them?

Yes. n5 is tighter than n6: at every diameter its limits fall inside the range n6 allows. The precision is simply higher than required, so the price may be a little higher.

Tell us the tolerance on your drawing and we will match it to stock. Write the size as 8(0/-0.015) or 8h7 and e-mail it with material, length and quantity to sfp@sfp-tw.com, or check availability directly in the online catalog. Stock dowel pins come in h6 / h7 / m6 as well as minus and plus tolerance; whenever the tolerance zone of a stock part lies entirely within the acceptance range on your drawing, it can ship straight away with no wait for custom production.

Values follow ISO 286-1; the table was cross-checked cell by cell against three independent sources on 2026-08-26 (6,674 cells agree, 0 errors). Coverage: shafts a–z and the corresponding uppercase holes, IT1–IT13, nominal sizes 0–500 mm. cd/ef/fg/za/zb/zc, sizes above 500 mm and grades above IT13 are not included: the tool reports "not found" and never extrapolates. Data sources and verification →

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