[O.B.Left]

Hinging is much easier and vastly more reliable than Swiveling. I think people misunderstand the Hinge because they don't align the Wedges at 90 degrees.

You raise an interesting question. The "vertical" of Hinge Action's left hand to the associated Basic Plane alignment. D, do you thinks it's a "geometrically" vertical thing again as opposed to literally vertical? Sorta like geometrically flat ? I think it must be to encompass the turned left hand grip types. From not turned all the way to the fully turned 10-2-D.

How can I describe this better? Say you had a turned left hand grip , turned any amount and you held a ping pong paddle like wise, with the paddles face vertical to the ground . To Hinge properly the paddle would maintain the vertical to the basic plane alignment despite the fact the hand is turned. The hands condition thus being considered "geometrically" vertical though not literally vertical.

Uh maybe I just made it worse with that attempt.