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198 Making Things Move

FIGURE 7-8 Linear ball bearing configurations (credit: McMaster-Carr)

Combination and Specialty Bearings
General-purpose radial ball and roller bearings are not designed to handle axial loads
or torques, and thrust bearings are not designed to handle radial loads or torques (see
Figure 7-9).

Ball bearings also tend to take up a lot of radial space, so they may not be feasible for
use in smaller projects. It can also be hard to align everything in your system perfectly
so the bearing functions as intended. Here are a few common bearing alternatives
that address these problems:

• Angular contact bearings If you try to put an axial load on a radial
bearing, it probably won’t work well, and the inner or outer race will likely get
damaged. However, in the real world, you rarely have pure axial or radial
loads. Angular contact bearings have angled races, so they can handle radial
loads as well as axial loads in one direction. Figure 7-10 shows a cross section
and the direction of the applied load.