Should Child Support cover class rings? I think this expense should be shared 50%? How can I enforce the x to pay?

I class ring is usually not an appropriate educational expense unless you have an agreement to the contrary.  A non-residential father has a problem when children become teenagers as they do have their own activities.  A good parent, at that time, remembers this and accomodates the teenager's activities as part of his time with the child.  Failure to do that will result in the child spending less time with the parent.  Whether he contributes towards the ring is between him and his daughter(or perhaps, input from you, done in a way to encourage it).