Deadweight: A fixed weight is set against the bearing ring while
            adhesive cures to retain the bearings. This system is used in many
            applications, and gives well-controlled torque values as well as 
            maximum stiffness. Disadvantages are cure time and special handling
            of adhesive in mass-production. Care must be taken to allow for
            relative thermal expansion effects if different materials are used
            in mating parts (see Thermal Expansion chart.)
            Spring: Spring (typically belleville-type) is used to press inner
            rings together, or a wavy-washer/spiral spring is used to push outer
            rings apart. This system is easy to assemble, but has minimum
            stiffness since the spring can move after assembly so that the
            stiffness of the assembly is controlled by the spring rate rather
            than bearing raceway/ball elasticity. Thermal effects from relative
            expansions of mating parts are minimized. Spring preload is often
            used in high speed applications.  
            Solid clamping: Component parts are machined to precise dimensions
            to remove axial play when races are clamped together. In theory,
            this system is easy to assemble, has few components and good
            stiffness. However, due to the wide range of axial play, it is
            almost impossible to achieve in practice. Unless components and
            bearings are matched to a high precision the resulting assembly may
            be damaged through raceway brinelling or may not have adequate
            preload. (Note: precision matched bearings are available as Duplex
            Pairs).