When Do I Start Rolling My Hands?

First off you actually should be rolling your forearms. Using your hands or wrists cold promote more of a "flip" rather than a solid roll. "Flipping" will also add loft to your golf club causing you to hit the ball higher and shorter.

The back of your left wrist, (for right handers) needs to be bulged slightly in order to create that solid feel at impact. The bulging will also help you reduce the club face loft adding distance and a lower more boring ball flight.

Here's how to get it done. First off let's consider impact at 12 o'clock. Hold the golf club in only your left hand, (again for right handers) and swing a very short back swing let's say to about two o'clock. Then while swinging the golf club back to impact begin "rolling" your left forearm BEFORE you get to impact. You should finish at about ten o'clock with your left palm facing upward.

I would do this drill with just your left hand a lot before attempting to add the right hand. Once you do add the right hand you should see the back of your right hand when finishing at the ten o'clock position.

I can show you a good drill for this by clicking here