I recall seeing a post where someone has rebuilt their roller timer, replacing the steel roller with a ball bearing. Sounds like a good idea, however doesn't the roller have to conduct current? Wouldn't a bearing be somewhat non conductive?
I did that once a long time ago. I believe it is a R4 Bearing. I think they are about the smallest general purpose bearing you can get that thew auto parts store.
I ran one for a couple years. A bearing is not made to conduct electricity. After two years the outer ring of the bearing was eroded away from constant sparking.
Other than that it worked well.
I had Bob's experience with wear on the outside of the bearing. That surface is meant to be stationary in the correct application, the wear being within the bearing. I had not considered the sparking contributing to the erosion.
As an aside, in a presentation to our local car club, a representative of a bearing company related a tale of woe regarding driveshaft bearings in a particular truck. It would regularly chew our driveshaft bearings every 30,000 mile or so. It took them 5 or 6 replacements before they discovered the wear was caused by electrical erosion. The answer was to switch the battery earth cables to the opposite chassis rail.
Allan from down under.
I had the same experience with electrical erosion on the one I modified to ball bearings. Roller bearings are not a good thing in this application.
If you're seeing it on the outside, imagine what it must look like on the balls and the inside of the races.