centerforce clutch problem

There's..........lots...........of.........causes........of..........clutch..........chatter..............

"Several" don't involve the clutch at all.................

Not arguing that point, this is not the first clutch ive done......... been in this biz a long time.......... this is VIOLENT chatter, worst chatter I have ever experienced ever! Got suggestion as to what you think it is? Try me, I'm not perfect and am looking for answers, it is out and on its way back to them, I find nothing other then their product at fault.