Shrink-fitting

Shrink-fitting is a technique in which an interference fit is achieved by a relative size change after assembly.

Other examples are the fitting of a wrought iron tyre around the rim of a wooden cart wheel by a wheelwright, or of a steel tyre to the wheel of a railway engine or rolling stock.

In both cases the tyre will be heated and expands to slightly greater than the wheel's diameter, and is fitted around it.

[1] A common method used in industry is the use of induction shrink fitting which refers to the use of induction heating technology to pre-heat metal components between 150˚C and 300˚C thereby causing them to expand and allow for the insertion or removal of another component.

Other methods of shrink-fitting include compression shrink fitting, which uses a cryogen such as liquid nitrogen to cool the insert, and shape memory coupling, which is achieved by means of a phase transition.