Tired of PDF tables, I keep a computed subset of ISO 286-2 in code — limits & fits for the hole-basis combinations that actually show up on drawings: IT5–IT8, shafts f/g/h/k/p, all 13 size bands to 500 mm. Plus ISO 2768-1 general tolerances.
Now it's a standalone MIT repo. Three ways to use it:
python iso286.py 25 H7/p6
# H7/p6 @ 25 mm [interference]
# hole 0 / +0.021 mm
# shaft +0.022 / +0.035 mm
# clearance -0.035 … -0.001 mm
Or the same module in TypeScript, or just fits.json as raw data.
https://github.com/chenzefeng09/iso-286-fits
Honest scope note: this is the common-design subset — shafts outside f/g/h/k/p, grades outside IT5–IT8, and shaft-basis fits aren't in it. For those you still need the full ISO 286-2 tables or an interactive lookup. The free browser version of this calculator lives at https://nxtolerance.com/standards if you want numbers without code.
Where it came from: I built this for a tolerance-analysis tool on NX .prt models, and realized the table itself was worth more released than locked inside one app. Corrections welcome — tabulated values match the standard, but a second pair of eyes never hurt.
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