double wrist cock?
 

could a double wrist cock cause a casting of the club?

could someone give me a defintion of swivel as it relates to the golfing machine?

I can try
 

I'd say possibly yes to the first question. If you double cock then you need to uncock your right wrist. If you did this at the top of your swing it could prematurely send the clubhead into orbit. That said, I believe for a swinger a double cock can prevent throwaway - this is referenced somewhere in the yellow book.

As to swivel, I think it is a roll of your wrists - generally associated with the left wrist I guess. With standard wrist action a swinger will swivel at the start of their back stroke, will then swivel back to impact (but not through impact - for this you hinge) and then swivel back to plane after follow through. A hitter with single wrist action will lose the start up swivel, won't therefore need to swivel back to impact, but will retain the swivel from followthrough back to plane.

As I understand hinge action, and I may be wrong here, if there is any rolling type action asides from the contribution of the pivot or non-rolling arms, it is contributed by the whole arm turning, not just the wrist.

Hope this is correct and that it helps!

Chris