Shaft, bore, and seal dimensional change with temperature. Linear growth, combined fit (clearance vs interference) across T₁→T₂, and multi-material CTE comparison. Treat results as an engineering starting point — verify against OEM fits and materials data.
Published method (linear thermal expansion)Last reviewed
Carbon steel (0.22% C), stainless 316 and brass / bronze (red brass, 85% Cu) coefficients match Agilent Table 17-1. The other coefficients are typical values; verify them for your materials.
Calculator
Dimension
Temperature
Component inputs
CTE: —
Shaft OD, bore ID, length, etc.
Results
Temperature delta
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Expansion / contraction
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Final dimension
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CTE applied
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Temperature conditions
Shaft
CTE: —
Measured at assembly temperature
Housing / bore
CTE: —
Measured at assembly temperature
Seal / third element (optional)
CTE: — (not selected)
Bore / OD reference at T₁
Shaft — linear expansion
OD at T₁
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OD at T₂
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Radial growth
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Diametral growth
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Housing / bore — linear expansion
Bore ID at T₁
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Bore ID at T₂
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Radial growth
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Diametral growth
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Seal — linear expansion
Dim at T₁
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Dim at T₂
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Growth
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CTE
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Fit analysis
Fit at T₁ (assembly)
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Fit at T₂ (operating)
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Fit change
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Differential CTE
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Rule of thumb: with a steel shaft or bearing in a steel or cast-iron housing, the parts grow at nearly the same rate, and a shaft running warmer than its housing grows faster than the bore, so fits tend to tighten. That is not always true. When the housing has the higher expansion coefficient, the bore grows faster and a press fit can become loose. Example: a 100 mm steel bearing (3.9370 in OD) in a 3.9365 in aluminum bore, heated from 70 to 200 °F, goes from a 0.0005 in press fit to about 0.0029 in clearance (0.00288 in with the coefficients on this page). The note above follows the numbers for your inputs.