Lead is the axial advance of a helix or screw during one complete turn (360°). The lead for a screw thread is the axial travel for a single revolution. Pitch is defined as the axial distance between adjacent threads on a helix or screw.
Lead angle is the angle between the helix and a plane of rotation.
|La||Lead angle (rad)|
|l||Lead of the helix (cm)|
|dm||Mean diameter of the helix (cm)|