Calculate press fit force from fit diameter, hub size, length and interference using typical material presets, or find the interference for a target force.

Nominal diameter of the joint: the shaft or pin outside diameter, which equals the hub bore.

Outside diameter of the housing, gear or hub around the bore.

Axial length of the pressed contact.

Shaft diameter minus bore diameter (total, not per side).

Typical room-temperature properties. Choose Custom to enter your own.

0.15 is a typical value for dry steel on steel. Lubricated fits are often 0.08–0.12.

Optional settings
For a hollow shaft or bushing. Leave blank for a solid shaft.

Optional. Adds a hoop-stress yield factor; leave blank to skip.

Press Fit Force Formula

The following equation is used to calculate the Press Fit Force.

Fₚ = p × A × u
  • Where Fp is the press fit force (N)
  • p is the contact surface interference pressure (N/m^2)
    • The contact surface interference pressure is dependent on the size, elasticity, interference fit, and Poisson’s ratios of the housing and sleeve.
  • A is the contact surface area (m^2)
  • u is the coefficient of friction between the bearing and housing

To calculate a press fit force, multiply the contact interference pressure by the contact surface area, then again by the coefficient of friction.

What is a Press Fit Force?

Definition:

A press-fit force is a required force needed to press a bearing, or similar object, into a housing.

How to Calculate Press Fit Force?

Example Problem:

The following example outlines the steps and information needed to calculate the Press Fit Force.

First, determine the contact surface interference pressure. In this example, the pressure is calculated to be 500 N/m^2.

Next, determine the contact surface area. This is measured to be .125 m^2.

Next, determine the coefficient of friction. For this example, the coefficient of friction is .56.

Finally, calculate the press fit force using the formula above:

Fp = p * A * u

Fp = 500 * .125 * .56

Fp = 35 N