[Yoda]

I would say Finish Swivel begins somewhere around when the left arm passes the left shoulder socket thingie.

Hinge Action -- holding the Left Wrist Vertical (or perpendicular) to one of the three Basic Planes (Horizontal, Vertical or Angled) -- is in operation from Impact to the end of the Follow-Through (Both Arms Straight position) per 7-10. The Arms will be well-extended past the Left Shoulder and the Clubshaft will be about 45 degrees to the ground. Then, Swivel Action -- "Snap Rolling the Hands into their On Plane Condition" (2-G; 4-0; 4-D-0) -- takes over as the Left Wrist Rolls from its Vertical alignment and creates the bridge to the Finish (12-3 #41).

In essence, Hinge Action is an Arm Motion (for Clubface Control) whereas Swivel Action is a Wrist Motion (for Clubhead Control).