Press Fit Calculator

Calculates elastic cylindrical co-axial pressure connections for compact or hollow shafts in either hot or cold state. The program calculates geometric parameters of the joint, minimal fit, standard or actual fit, and pressed-on parts material selection.

The calculation is only valid for press fits in which permanent deformations will not occur after the connection. The deformations do not include trueing of peaks and ridges on the surface texture.

This calculation is only valid for connections that are not loaded by outside pressure or are made from tubular parts with unlimited length. The parts are made from materials that behave according to Hooke's law.

The calculation does not consider the influence of centrifugal forces, ribs, or other reinforcement parts or in parts where the temperature is distributed unevenly.

A press fit joint with unlimited length is a joint with the length that equals the diameter or greater. If it is shorter, the real contact pressure is greater than calculated. This calculation provides more safety against the press fit loosing.

General information

Minimal interference is determined when securing the least required loading capacity of the press fits, together with other factors.

The maximum interference is determined without existing plastic deformation, according to the HMH plasticity condition (Huber, Misses, Hencky) together with other factors.

Pressing speed must be slow (about 3 mm/s ~ 0.12 in/s) while making the press fit. High speed reduces load capacity of the fit.

Calculated temperatures must be considered as minimum, because they do not consider temperature averaging during the pressing process, nor the hub cooling time after pulling it from the furnace, for example.

Tip: See the Engineer's Handbook for formulas, materials, and other instructions used for designing elastic press fits.