When creating helical gears:
It may not be necessary to understand the relationship between transverse and normal pressure angle but understanding how those values are displayed in GearTrax may be useful. The transverse pressure angle is measured in the plane of rotation and is always greater than the normal pressure angle. The pressure angle displayed in GearTrax is the normal pressure angle. The transverse pressure angle may be displayed by clicking on the More information button in the upper right hand corner of the Pressure angle text box.
The transverse pressure angle is effectively the real pressure angle.
The normal pressure angle is defined as normal to the cutter.
Transverse pressure angle = ATN(TAN(normal pressure angle) / COS(helix angle))