Another cool way to look at hinge action is via spherical circles.
Imagine that globe I described on the left shoulder. For the left arm to be lifted (circle 1). The positioning of the second circle (circle 2) however is dependant on the clubface motion you desire through impact - horizontal hinge action produces a circle horizontal to the ground - vertical will be vertical - angled will be angled ...etc but all referenced to the ground.
Homer used hinges as an alternative way to more easily communicate these ideas.
I believe that these circles or axis are positioned globally around the left shoulder rather than locally with so that these circles don't chance in regards to what the moving left shoulder does during the stroke....
There is something im missing though with regards to the orientation of the pin relative to the ground and/or inclined plane...just got a feeling about it.... With 1-L and its angled and vertical equivalents, the pin is flat against a plane that goes 90 degrees through the ground and inclined plane. What im wondering is what would happen if you changed this....
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