In article ,
granpaw wrote:

I do not advocate the use of electric sharpening stones, I have used
them and found them IMHO to do more harm to a chain than good, as it is
near impossible to reliably do each tooth exactly the same.

Clearly, opinions differ. Grinding setups may differ - sounds like you
have used something with no jig or stop mechanism. With a proper chain
grinding setup, it's quite trivial (in my experience) to do all the
teeth essentially the same, and that is why I have that done after
several cycles of filing, or hitting something that makes filing a major
chore. My chains develop a "handedness" drift over time (it's difficult
to file each tooth the same when half of them point the other direction
- the left and right hands do not file the same, nor does the right hand
when asked to go backwards - same strokes and trying to use the same
pressure notwithstanding). A jigged grind job clears this right up,
which means it's more consistent than I can manage with a file.

--
Cats, coffee, chocolate...vices to live by