non-metallic, will operate against most metals, but better performance
is obtained with the hardest available mating surfaces. Hardened steel,
hard anodized aluminum, hard chrome or nickel plate are recommended.
A surface hardness of 45-50 Rc is desirable, but satisfactory
performance can also be obtained with softer materials. Generally, a
surface finish on the mating components of 16-32µ inch should be provided.
Shaft materials or surface treatments should be selected that will effectively
resist corrosion. Transport Dynamics recommends a max surface finish
of 32 Rms and minimum hardness of 40Rc.
To determine the
approximate reduction in life for different values of shaft finish and
hardness, see below.