Definitions for "Helix Angle"
The angle of a screw flight at its periphery relative to a plane perpendicular to the screw axis. It is calculated as: Helix Angle = Arctangent ( Lead) Pi x D)
On a straight thread, the helix angle is the angle made by the helix of the thread and its relation to the thread axis. On a taper thread, the helix angle at a given axial position is the angle made by the conical spiral of the thread with the axis of the thread. The helix angle is the complement of the lead angle. (See also page 1717 for diagram.)
the constant angle at which a helix cuts the elements of a cylinder or cone