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Fits & size limits

Tolerance width versus allowance between mating parts

A tolerance width belongs to one size interval. A clearance or interference value compares two mating sizes. Keep the sign convention visible.

Sources and scope ↓

One part: width

For a hole from 25.000 to 25.021 mm, the tolerance width is 0.021 mm. That number alone says nothing about the shaft.

Two parts: signed difference

This page uses Hmin − Smax as the signed minimum diametral clearance at the maximum-material size limits. With the 25 H7/g6 example it is +0.007 mm; negative means interference. This explicit arithmetic convention is not a reproduction of an unreviewed standards definition of allowance.

Continue your task

Calculate clearance from hole and shaft limits →MMC and LMC: identify the material-size boundary →Start with the fit you need to understand →

All tolerance and surface references →

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.

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KHK hole tolerance table

Manufacturer table explicitly excerpting JIS B 0401-2:1998. H7 row for 25 mm: 0 / +21 µm.

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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.

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