An evidence-backed width example
At nominal 25 mm, the cited H7 limits are 25.000–25.021 mm, a width of 21 µm. The h6 limits are 24.987–25.000 mm, a width of 13 µm. These are KHK’s published legacy JIS table examples, not a full current ISO 286 table reproduction.
Why the grade alone is insufficient
The same grade number has different widths across nominal-size intervals. The width also does not say whether a zone is above, below or touching the nominal size. Read the letter and relevant table row separately.
Which document supplies what?
ISO 286-1 describes the code system and terminology; Part 2 supplies the standard tolerance grades and limit deviations. The public abstracts do not substantiate an entire numeric table. Open the linked source for your actual size and edition.
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Sources and review scope
Reviewed 23 October 2026. Arithmetic examples are labelled separately from source-table facts and standard scope.
ISO 286-1:2010
Public catalogue: terminology, code system and scope. Full clauses not reviewed.
Open the original source ↗ISO 286-2:2010
Public catalogue: limit-deviation tables are in Part 2; abstract does not verify numeric rows.
Open the original source ↗KHK hole tolerance table
Manufacturer table explicitly excerpting JIS B 0401-2:1998. H7 row for 25 mm: 0 / +21 µm.
Open the original source ↗KHK shaft tolerance table
Manufacturer table excerpting JIS B 0401-2:1998. At 25 mm: h6 −13 / 0 µm; g6 −20 / −7 µm. These are scoped examples, not a full ISO table audit.
Open the original source ↗