Going to repost some info here from a old site I helped run.
Ive seen some racechains with the outside of the tooth lightly grinded, i suppose its for a more square tooth and a narrower cut. I was wondering how to do this? I have heard or putting it backwards on a saw and the use of a stone,but sounds dangerous to me
Are you talking about stoning the cutters or actually thinning the cutters from the outside?
Stoning the cutters
I was told long ago to use about a 8" flat diamond sharping stone.
A cheap 8" whetstone will do it for you.