Hole and shaft classes
ISO 286 fits
Inputs
Hole classH9
- ES
- 0.087
- mm
- EI
- 0
- mm
Shaft classn8
- es
- 0.077
- mm
- ei
- 0.023
- mm
Results
Fit
Transition fit
H9/n8
Loosest — clearance
0.064
mmES − ei = 87 − 23 = 64 µm
Tightest — interference
0.077
mmes − EI = 77 − 0 = 77 µm
Hole width IT9 87 µm
Shaft width IT8 54 µm
Hole max 100.087 mm
Shaft max 100.077 mm
Hole min 100.000 mm
Shaft min 100.023 mm
cmax = ES − ei imax = es − EI
Nearby: Tolerance stack · Position deviation · MMC bonus & virtual condition · Process capability Cp/Cpk
Method
Formula, when it applies, and when it does not
Hole and shaft limit deviations, clearance and interference from ISO 286:2010 classes.
cmax = ES − ei imax = es − EI
When
- ISO 286-1/2:2010 tables, nominal sizes above 0 mm up to 500 mm.
- Hole-letter deviations are the inverse of the matching shaft letter.
- IT grades 5–12. js/JS is symmetric ±IT/2.
Don’t
- Not a gauge-design or inspection plan. K/M/N hole values that ISO makes IT-grade dependent are the common inverse approximation. Not valid above 500 mm.