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Fits & size limits

Interference fit: distinguish size overlap from capacity

If the entire signed clearance interval is negative, the size limits imply interference. That does not calculate contact pressure, transmitted torque or a safe assembly method.

Sources and scope ↓

Keep the signs

Hole 20.000–20.010 mm and shaft 20.020–20.030 mm give signed diametral clearance −0.030 to −0.010 mm. Expressed positively, the interference is 0.010–0.030 mm. These are assumed limits for an arithmetic example.

What to establish next

Confirm material properties, hub/shaft geometry, form and finish, stress limits, temperatures and mounting method. A thermal-expansion estimate addresses only one part of assembly; it cannot prove joint strength.

Continue your task

Calculate clearance from hole and shaft limits →Estimate free thermal expansion of a bore →Bearing fit is different from internal clearance →

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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NIST — Uncertainty and Dimensional Calibrations

Printed p. 650, equation (1): linear temperature correction and coefficient/temperature uncertainty. Heating model here is an algebraic estimate, not a mounting procedure.

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