There is a ring that keeps the knob (swivel / don't swivel) from being turned too far in either direction. For the early models, it was possible to turn the knob too far back and bend the ring or ride over top of the ring. Then it would no longer tighten down properly.
That issue has been corrected with all manufactured since May 1. But there are some older units in the store with the smaller ring. They should have been repaired or sent back for replacement.
There are ball bearings in the swivel. They are not the standard bearings. I have forgotten what the engineer called them.
No lubrication needed. As Rob noted earlier, these bearings are not subjected to a lot of stress since the speed of rotation is not like a piece of machinery at several hundred RPMs but rather an occassion slow twist.
