Obtaining Meaningful Surface Roughness Measurements on Gear Teeth

Surface roughness measuring of gear teeth can be a very frustrating experience. Measuring results often do not correlate with any functional characteristic, and many users think that they need not bother measuring surface roughness, since the teeth are burnished in operation. They mistakenly believe that the roughness disappears in a short amount of time. This is a myth! The surface indeed is shiny, but it still has considerable roughness. In fact, tests indicate that burnishing only reduces the initial roughness by approximately 25%.