Engineering lab · Interactive tool

Thermal Fit + Clearance Calculator.

Track how independent temperatures and material expansion rates shift the diametral relationship between a shaft and bore.

Thermal fit screening / independent component temperatures

Live calculation

01Diameters + materials

02Temperature states

Thermal fit between a shaft and boreConcentric shaft and bore diameters change independently with temperature.SHAFTBOREDIAMETRAL FIT
Uniform linear expansionΔD = D · α · ΔT
Initial clearance0.02 mmbore minus shaft
Final clearance0.04204 mmClearance
Clearance change0.02204 mmthermal shift
Final conditionClearanceBore 25.066 · Shaft 25.024 mm

Temperature can reverse a nominal fit

This first-order model applies uniform linear expansion to the bore and shaft independently, making it useful for quick assembly, operating-temperature, or material-pair screening.

For critical fits, apply the full manufacturing tolerance limits and evaluate contact pressure, gradients, transient states, coatings, and constrained deformation.

Before releasing a thermal fit

  • Evaluate hot, cold, startup, shutdown, and assembly states
  • Use temperature-dependent material properties where needed
  • Include full shaft and bore tolerance limits
  • Check interference pressure and material yield
  • Account for gradients, constraint, coatings, wear, and surface finish

Direct senior involvement

Turn the product decision into a clear next step.

Share a non-confidential summary, the current stage, and the outcome the team needs.

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