Free Press Fit Calculator
Calculate the interface pressure and required assembly force for a cylindrical press fit joint.
Interface Pressure
150.0 MPa
Interface Pressure vs Diametral Interference (delta)
Press Fit (Interference Fit) Analysis
A press fit creates a joint by assembling a slightly oversized shaft into a slightly undersized hole.
Simplified Formula (solid shaft, same material)
p = delta E (1 - (d/D)^2) / d
where delta is the radial interference (diametral/2), d is shaft diameter, D is hub OD, and E is the elastic modulus.
Assembly Force
F = pi d L p mu
where L is the engagement length and mu is the friction coefficient.
Example Calculation
A 50 mm shaft pressed into a hub (OD=100 mm) with 0.05 mm diametral interference, 40 mm long, steel.
- 01k = (50/100)^2 = 0.25
- 021/(1-0.25) = 1.333
- 03p = 0.05 x 200,000 / (50 x 1.333) = 10,000 / 66.67 = 150 MPa
- 04F = pi x 50 x 40 x 150 x 0.15 / 1000 = 141.4 kN
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