[okie]

Hey Driver

That question covers a lot of different topics. I think much of this can be researched best by using the search function. Here are some suggestions for key words :

-"hinge action"

- "swivel"

-"release triggers"

-"geometry of the circle"

In regard to hitting it fat; I would say that with a Level Left Wrist at Fix, Extensor Action and a steady left shoulder (achieved via a steady non bobbing or swaying Head) hitting it fat should be near impossible.

To draw a perfect circle you must have a fixed center and a properly extended radius. Like a string line from nail to pencil used by a carpenter to draw a curve, the left arm and club (Primary Lever Assembly, the radius) must be held taut via extensor action at fix to properly measure the correct distance from the Left Shoulder (center) to the ball. Once measured, nail the Left Shoulder or the Head into position.

If the Left Wrist is cocked slightly at Fix (slack in the string, bad measurement) and then stretched to a fuller extension dynamically during the swing OR if your Left Shoulder moves closer to the ball during the swing (not nailed).......you'll hit it fat. If you measure properly and nail it down but then let your string (Primary Lever Assembly) go slack during the swing you'll hit it thin. Most people encountering this latter situation develop a head bob or lowering as a compensation. This works to the extent that they can maintain a consistent radius with an un stretched Primary Lever Assembly.........which is hightly doubtful........... for that reason the carpenter uses a taut string line and so should we.

The added benefit to Extensor Action is increased velocity via a wider arc, increased structure and mass which adds to the blow to the ball. Velocity and mass, every golfer has to like that.

Hope this helps.

Nice primer, OB!