The most common problems are out-of-time (the hands don't correspond
to the right positions -- internal gear slippage), stripped rack or
pinion gear, or jammed due to dirt. The Starrett indicators are
pretty good, Ames are more rugged, and CDI are pretty but not as
well made. I have less experience with the imports. Since you
really can't get sperm whale oil anymore, you have to use a good
synthetic lubricant. Get some watchmaker's oil.

Dave wrote:
I recently picked up two nice older indicators on Ebay; one analog, one
digital. It seems that older indicators tend to go fairly cheaply
(especially true if they are not Starrett or Mitutoyo or another big
name). My question is this -- what common problems might be found with
such older units and what cautions should apply to cleaning them up?
Thanks!