An effective and versatile alternative now attracting attention is to use a special type of spring fastener called a tolerance ring.
Explains Roger Cornwell of tolerance ring market leader Rencol: “These high-precision fasteners are specifically designed for jointing annular components. The fasteners take the form of an engineered ring which has wave forms around the circumference. These wave forms locate against the two surfaces to be joined to create a high-performance interference fit. The rings are simply press-fit into position, a process which can be carried out manually or automatically, depending on the production environment.”
The ring specification can be precisely tailored to the application, through material selection and by modifying the pitch of the wave forms. Rings can be made from as small as 3 or 4mm in diameter up to and beyond 1000mm. This type of joint readily accommodates differential thermal expansion and can be specified to withstand extreme temperature ranges without loss of performance. Because the rings are made from metal they can also conduct heat, when required.