Thanks for the reply.
My class and I had so much trouble with the foldover crimps last Thursday that I've finally given up on them. I have been using the same crimping pliers since last fall 2007. I'm wondering for how long they work well as I didn't have any trouble making foldover crimps when we first starting using these pliers. The 2x2 reinforced sterling silver crimp tubes were from Artbeads.
I'm going to start using the twisted crimps from Artbeads for the classes and sell the twisted crimps to my students and that should take care of the problem.
I will try the scrimps to see how they hold up.