Hello Michael,

Maybe an image (attached) will show you better what i'm trying to say : )

This will place the rotation axis to the 'right' place, where i draw a construction line, and the Extrusion will begin from there.

EDIT: If the rotation of a face must be 'settle' in one single edge, this edge (axix) needs to be offset back by half of the distance between the 2 paralel edges.

Carlos