[bray]

Mine doesn't for putting, chipping (angled hinge for both) and pitching (vertical hinge).

Calling Annikan Skywalker,

I believe the left arm connects to the shoulder by a "ball in socket" joint because of this any motion of the left arm back and through will have external and internal rotation (not always in that order) whether you are tracing a straight line or not. The amount of rotation may be very small but there will be some.

I will wait for someone with a much better understanding of biomechanics than I to post and confirm or deny my conclusion above.

Sorting Through the Golf Nut's Catalog.

B-Ray