Press fit in the context of Fit (manufacturing)

A train wheel or rail wheel is a type of wheel specially designed for use on railway tracks. The wheel acts as a rolling component, typically press fitted on to an axle and mounted directly on a railway carriage or locomotive, or indirectly on a bogie (CwthE) or truck (NAmE). The powered wheels under the locomotive are called driving wheels. Wheels are initially cast or forged and then heat-treated to have a specific hardness. New wheels are machined using a lathe to a standardised shape, called a profile. All wheel profiles are regularly checked to ensure proper interaction between the wheel and the rail. Incorrectly profiled wheels and worn wheels can increase rolling resistance, reduce energy efficiency and may even cause a derailment. The International Union of Railways has defined a standard wheel diameter of 920 mm (36 in), although smaller sizes are used in some rapid transit railway systems and on ro-ro carriages.

An arbor press is a small hand-operated press. It is typically used to perform smaller jobs, such as staking, riveting, installing, configuring and removing bearings, and other press fit work. Punches, inserters, or other tools/dies may be added to the end of the ram depending on the desired task. Arbor presses are usually rated by the ideal force that the leverage bar can apply. Typically common are presses with a leverage of one to five tons. This leverage is achieved when a force is applied to the lever arm or wheel.

Arbor presses can be mounted on a work bench, wall, or pedestal. The base is usually constructed of cast metal. A ram provides the force; it may be square or round. The ram is usually driven by a rack and pinion. Higher force arbor presses have a further gear reduction. Forces are usually generated by manual or hydraulic input.