The bearings are comprised of two rings, each of which contains a precision raceway that is induction hardened on the surface to a specified depth. Each ring is made from a medium carbon steel forging. Silverthin™ SK and ST Series bearings have raceways constructed in Slewing Ring Turntable a four-point contact configuration, with 45° contact angles as standard. Other raceway configurations are available, such as crossed roller and eight-point contact. These other options are often considered in cases where very high loads or special stiffness requirements are needed.
Precision rolling elements (specifically hardened chrome alloy steel balls for Silverthin™ SK and ST Series bearings) facilitate relative ring rotation between the inner and outer rings. Rollers as rolling elements are also often used.
Spacers, typically made from a SKF 22222 Bearing plastic material, are commonly used to separate balls to prevent them from rubbing directly against each other. Sometimes spacer balls are utilized instead of spacers. In this case these are balls that are slightly smaller than the load carrying balls, placed between each load carrying ball. Occasionally, application parameters warrant the use of a separator.