I've made the chain link by bending and mirroring a cylinder (without end caps). I did it this way because the object is oval rather than circular. Also, I find it easier to control the polygon number.

This is the smallest practical one I could make ... from an 8 sided cylinder ... 18KB. 6,5,4,& 3 sided cylinders tended to look a little "clunky" !

I'll use it to make a ball and chain !