Press Fit & Interference Fit Pressure Calculator

Inputs

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Diameter at the shaft/hub interface (the nominal mating diameter).
mm
Outside diameter of the hub (outer member). Must exceed the interface diameter.
mm
Diametral interference: shaft diameter minus hole diameter (the total, not the radial, value).
mm
Axial length over which the shaft and hub are in contact.
mm
Coefficient of friction at the interface; dry steel-on-steel is typically 0.1–0.2.
Both parts, same material; steel ≈ 200,000 MPa.
MPa
Hub material linear expansion coefficient used for the shrink-fit temperature estimate. Carbon steel is about 12 µm/m·°C.
µm/m·°C

Results

Default result
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Contact pressure(p)
48.75MPa

Interface pressure between shaft and hub.

Also computed

Assembly force(F)45,950N

45.95 kN · 4.69 t

Axial force to press the shaft in (F = π·μ·p·d·L).

Torque capacity(T)1,149N·m

Torque the friction joint can transmit before slipping.

Hub hoop stress(σ)Pass111.3MPa

Peak tangential stress at the hub bore.

Shrink-fit temp rise(ΔT)66.67°C

Temperature rise above the shaft temperature, before extra handling/heat-loss margin.

Hub-only temperature rise to expand the bore by the entered interference.

Method notes 4 notes
  • Lamé thick-cylinder result for a solid shaft pressed into a same-material hub; contact pressure p = (E·δ)/(2·d) · (d₀²−d²)/d₀².
  • Press-in force and torque capacity use the friction coefficient μ — pick it conservatively, as it is the largest source of uncertainty.
  • Shrink-fit temperature rise uses ΔT = δ/(α·d) for hub expansion only; add shop margin for transfer time and heat loss.
  • Ignores surface-roughness flattening (which reduces the effective interference), service temperature and centrifugal effects; check the hub hoop stress against its yield strength.

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