Fretting?

I have seen evidence of fretting on both ends of a shaker motor shaft. (Eccentric counterweight wheels) This was on the surfaces under taperlock bushings that were apparently tight. There was a salt atmosphere. what causes this phenomena?
Ron Jacobson

 

[gbent]

I believe the cause is very minute movement between the two mating parts. Even though the joint may be tight, some movement can occur, such as twisting in the driving shaft. I don't know how to solve it, but if the joint stays tight between rebuilds, I would ignore it.

 

[boo1]

Agree, suspect the fit was not tight. If remachining taper is not in the plan, try a structural shimming compound like "Dynamold M-26", make shure to use a release film on one surface.