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 calculationΔD = D · α · ΔTThermal fit results updated. Final clearance 0.04204 millimeters. Final condition Clearance.
Model, assumptions, and a reproducible reference case
D_final = D_initial(1 + αΔT); clearance = bore − shaft
Reference inputs
Bore 10 mm, α = 23 µm/m·K; shaft 9.98 mm, α = 12 µm/m·K; both change from 20°C to 120°C.
- Expected final diametral clearance
- 0.031024 mm
- Calculated by this tool
- 0.031024 mm
Uniform temperatures and constant CTE are assumed. Contact pressure, restraint, gradients, tolerances, and material transitions are excluded.
Check the material basis, load cases, and applicable design criteria before using a result. Warning thresholds are prompts for review, not acceptance criteria.
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
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