MechPilotISO 286 fits: limit deviations and clearances
A fit is a hole and a shaft of the same nominal size with their tolerance classes, written hole first: H7/g6. These are common hole-basis fits; each page lists the limit deviations and the resulting clearances for every size step up to 500 mm.
Values are computed from MechPilot’s ISO 286 data by the rules of ISO 286-1, the same way the app computes them. A negative clearance is an interference. ISO fits explained · ISO 286 standard tolerance grades IT01 to IT18
| Fit | Kind (over the size range) | Max. clearance at 25 mm (µm) | Min. clearance at 25 mm (µm) |
|---|---|---|---|
| H11/c11 | Clearance | +370 | +110 |
| H9/d9 | Clearance | +169 | +65 |
| H8/f7 | Clearance | +74 | +20 |
| H7/g6 | Clearance | +41 | +7 |
| H7/h6 | Clearance | +34 | 0 |
| H7/js6 | Transition | +27.5 | −6.5 |
| H7/k6 | Transition | +19 | −15 |
| H7/n6 | Transition | +6 | −28 |
| H7/p6 | Transition, Interference | −1 | −35 |
| H7/s6 | Interference | −14 | −48 |
| H7/u6 | Interference | −27 | −61 |
At 25 mm: the size step over 24 up to 30 mm.
Source and verification
- Standard
- ISO 286-1:2010 Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 1: Basis of tolerances, deviations and fits; ISO 286-2:2010 Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts
- Verification
primary(the standard’s own text was seen)- Verified from
- https://cdn.standards.iteh.ai/samples/54915/7d6147c29fed4e31af36b60561e88752/ISO-286-2-2010.pdf (ISO 286-2:2010 preview: Table 1; Tables 2 and 3 for holes A to E)
- https://law.resource.org/pub/in/bis/S01/is.919.1.1993.pdf (IS 919 (Part 1):1993, identical with ISO 286-1:1988: clause 9, Tables 2 and 3, Annex A)
- https://cdn.standards.iteh.ai/samples/45975/c0a5df14167f48eebc6c17dc4da5f9c4/ISO-286-1-2010.pdf (ISO 286-1:2010 preview: terms and definitions only, no tables)
- Verification notes
- itGrades: ISO 286-2:2010 Table 1 (reproduced there from ISO 286-1:2010), read from the standard's own preview on 2026-10-22. IT01 and IT0 are not given above 500 mm (null).
- fundamentalDeviations: read from ISO 286-1:1988 Tables 2 (shafts) and 3 (holes) in the identical Indian adoption IS 919 (Part 1):1993. The 2010 edition's Tables 2 and 3 were not seen. Holes A, B, C, D and E were cross-checked against ISO 286-2:2010 Tables 2 and 3 (lower limit deviations EI) and agree for every size step up to 500 mm. The other letters come from the 1988 edition only (see docs/to-verify.md).
- The Delta values equal IT(n) - IT(n-1) of itGrades for every step above 3 mm; scripts/check-library.mjs checks this.
- Data file
library/fits/iso-286.json
Values that could not be checked against the standard are left out and listed in docs/to-verify.md. Check the standard itself before you rely on a value for production, and report any mistake on GitHub. to-verify.md · Issues