Press Fit Calculator
Calculate contact pressure and estimated assembly force for interference (press) fits using simplified Lamé equations.
How to Use the Press Fit Calculator
- Enter the interference (difference between shaft and hole diameter) in mm.
- Enter the shaft diameter in mm.
- Enter the elastic modulus of the shaft material in GPa.
Use Cases
- •Designing press-fit bearing seats.
- •Estimating press forces for manufacturing.
- •Verifying interference fit designs in shafts and hubs.
Formula
P = δ × E / (2r), where δ is interference (mm), E is elastic modulus (MPa), r is shaft radius (mm). Assembly force estimated with friction coefficient μ = 0.12.
Frequently Asked Questions
What is an interference fit?
An interference fit (press fit) is a joint where the shaft diameter is slightly larger than the hole, creating a friction-based connection without fasteners.
What elastic modulus should I use for steel?
For steel, use approximately 200–210 GPa. For aluminum, use ~70 GPa. For cast iron, use ~100–170 GPa.
Is this calculator free?
Yes, all OhMyCalc calculators are completely free to use.